WO2018168403A1

WO2018168403A1 - Base material for back grinding tape

Info

Publication number: WO2018168403A1
Application number: PCT/JP2018/006742
Authority: WO
Inventors: 洋佑高麗
Original assignee: リンテック株式会社
Priority date: 2017-03-14
Filing date: 2018-02-23
Publication date: 2018-09-20
Also published as: TWI822670B; JPWO2018168403A1; TW201839081A; JP7069116B2

Abstract

[Problem] To provide a base material for a back grinding tape, which cannot be adhered onto an adsorption table excessively when a semiconductor wafer is heated on the adsorption table and can be removed easily from the adsorption table during the attachment of an adhesive sheet onto the semiconductor wafer after a back surface polishing process. [Solution] The base material for a back grinding tape according to the present invention is a cured product of a base material layer forming composition containing urethane (meth)acrylate and a polymerizable compound having an energy-ray-polymerizable group, and has a tensile storage modulus of 8 MPa or more at 80ºC.

Description

Back grinding tape substrate

The present invention relates to an adhesive tape substrate used when backgrinding an adherend such as a semiconductor wafer, that is, a backgrind tape substrate.

Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state. After a circuit is formed on the front surface of the semiconductor wafer, the semiconductor wafer is ground to a predetermined thickness by back surface grinding, and is cut and separated (diced) into element pieces (semiconductor chips), and then transferred to the next bonding step. .

In the back grinding process, an adhesive tape called a back grind tape is used to hold the wafer during grinding and to protect the circuit surface from grinding debris. Further, following the back surface grinding process, circuit formation or the like may be performed on the ground surface, and also in this case, the wafer is protected and fixed with an adhesive tape for processing. The pressure-sensitive adhesive tape used for back surface processing such as a back grind tape is composed of a base material and a pressure-sensitive adhesive layer having pressure-sensitive adhesiveness. In particular, an adhesive tape using a base material that is relatively soft and has high stress relaxation properties may be used in order to reliably protect the circuit surface having irregularities on the surface.

As an example of such a pressure-sensitive adhesive tape, Patent Document 1 (WO2013 / 141251A1) proposes a back grind tape having a pressure-sensitive adhesive layer on at least one side of a substrate. Patent Document 1 discloses a substrate formed by forming and curing an energy ray curable composition containing a urethane acrylate oligomer, an energy ray polymerizable monomer, and a polymerizable silicone compound.

In the back grinding process, the semiconductor wafer is fixed to the suction table via the back grind tape in the wafer back grinding machine. And after the back surface grinding process, as shown in FIG.1 and FIG.2, the adhesive sheet 2 is affixed on the grinding surface of the wafer 1. FIG. The adhesive sheet 2 may be pre-cut according to the outer diameter of the ring frame 3, or may be cut according to the shape of the ring frame 3 after being attached. After adhering the adhesive sheet 2, as shown in FIG. 3, the wafer 1 is lifted from the suction table 20 together with the back grind tape 10 by the transfer mechanism (transfer arm 4) built in the wafer back grinding apparatus and transferred to the next process. To do. The back grind tape 10 includes a base material 6 and an adhesive layer 5. In addition, the adhesive sheet has the functions of a single layer film adhesive, a laminate of film adhesive and release sheet, a laminate of dicing tape and film adhesive, and both dicing tape and die bonding tape. Examples thereof include a dicing die bonding tape composed of an adhesive layer having a release sheet and a release sheet.

Since the adhesive sheet generally has a low tack at room temperature, the adhesive sheet is often applied while heating the semiconductor wafer. In such a process, the adhesive sheet is softened by heating to improve the adhesion between the adhesive sheet and the wafer. Heating the wafer may be performed by heating the wafer pasting area on the suction table to 60 to 80 ° C. Also, the heating time for the wafer may be over 30 minutes. For this reason, in such a heating process to the wafer, heat is transmitted to the back grind tape (particularly the base material) in contact with the suction table, and the back grind tape (particularly the base material) is also heated. The substrate of the back grind tape is softened by heating and may be in close contact with the suction table, and even if a transfer arm is used, the wafer may not be lifted from the suction table. Such a process failure occurs more significantly when the surface of the suction table has a porous structure. When such a process failure occurs, the wafer cannot be transferred to the next process, so that the production efficiency of the semiconductor device decreases.

WO2013 / 141251A1

The present invention has been made in view of the above-described prior art, and when a bonding sheet is pasted on a semiconductor wafer after a back surface grinding step, the substrate remains on the suction table even if the semiconductor wafer is heated on the suction table. It is an object of the present invention to provide a base material for back grind tape that does not excessively adhere to the surface and can be easily peeled off from the adsorption table.

The gist of the present invention aimed at solving such problems is as follows.
[1] A cured product of a composition for forming a base layer comprising a urethane (meth) acrylate and a polymerizable compound having an energy ray polymerizable group,
A substrate for back grind tape having a tensile storage elastic modulus at 80 ° C of 8 MPa or more.

[2] Adsorption pressure on the adsorbing table heated to 80 ° C. on the substrate side of the laminate obtained by laminating a 75 μm thick PET film, a 20 μm thick adhesive layer, and a 50 μm thick backgrind tape substrate After adsorbing and holding at 85 kPa for 30 minutes, the adhesion between the substrate and the adsorption table is 1 N or less when the laminate is peeled from the adsorption table at a peeling angle of 30 ° and a peeling speed of 300 mm / min. [1 ] The base material for back grind tapes as described in above.

[3] The substrate for back grind tape according to [1] or [2], wherein the number of energy ray polymerizable groups in the polymerizable compound having the energy ray polymerizable group is 3 or more.

[4] The content of the polymerizable compound having an energy beam polymerizable group is 5 to 10% by mass with respect to the total amount of the composition for forming a base material layer, according to any one of [1] to [3] Back grinding tape base material.

[5] The back grind according to any one of [1] to [4], wherein the composition for forming a base material layer includes a polymerizable compound having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms. Tape base material.

[6] The backgrind tape group according to [5], wherein the composition for forming a base material layer contains two or more polymerizable compounds having the heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms. Wood.

[7] A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer on at least one surface of the backgrind tape substrate according to any one of [1] to [6].

The substrate for back grind tape according to the present invention has heat resistance and is not easily deformed by heating. Therefore, even if the semiconductor wafer is heated on the suction table in the wafer back grinding apparatus, the substrate does not excessively adhere to the suction table, and the peelability from the suction table is excellent. As a result, the wafer can be transferred without any trouble by the transfer mechanism built in the wafer back grinding apparatus, and the production efficiency of the semiconductor device can be improved.

FIG. 1 is a schematic diagram illustrating a process of attaching an adhesive sheet to a ground surface of a wafer after a back surface grinding process. FIG. 2 is a schematic diagram illustrating a wafer transfer process. FIG. 3 is a schematic diagram illustrating a wafer transfer process. FIG. 4 is a perspective view of a state in which a peeling tape is attached to the outer edge portion of the sample for measuring the adhesion force. 5 is a cross-sectional view taken along line AA in FIG. FIG. 6 is a schematic diagram showing a method for measuring the adhesion force. FIG. 7 is a schematic diagram showing the peeling behavior at the interface between the back grind tape and the suction table.

The present invention will be specifically described below. First, main terms used in this specification will be described.
In this specification, for example, “(meth) acrylate” is used as a term indicating both “acrylate” and “methacrylate”, and the same applies to other similar terms.

An adhesive tape means the laminated body containing a base material and the adhesive layer provided in the one surface side of the base material, and does not prevent containing other structural layers other than these. For example, a primer layer may be formed on the surface of the base material on the pressure-sensitive adhesive layer side, and a release sheet for protecting the pressure-sensitive adhesive layer may be laminated on the surface of the pressure-sensitive adhesive layer until use. . Further, the substrate may be a single layer or a multilayer. The same applies to the pressure-sensitive adhesive layer.
The “front surface” of the semiconductor wafer refers to the surface on which the circuit is formed, and the “back surface” refers to the surface on which the circuit is not formed.

[Background tape base material]
The base material for back grind tape which concerns on this invention is a hardened | cured material of the composition for base material layer formation containing urethane (meth) acrylate (a1) and the polymeric compound (a2) which has an energy-beam polymeric group. , the tensile storage modulus at ₈₀ ℃ (E '80) is not less than 8 MPa. In the following, “back grinding tape substrate” may be simply referred to as “substrate”.
When the semiconductor wafer is heated in the wafer back grinding apparatus, the suction table may be heated to about 60 to 80 ° C. to propagate the heat to the semiconductor wafer. Since the semiconductor wafer is placed on the suction table via the back grind tape, the back grind tape (particularly the base material) is easily affected by the heat of the suction table. When the tensile storage elastic modulus (E ′ ₈₀ ) at 80 ° C. of the substrate is less than ₈ MPa, the substrate adheres to the adsorption table when the adsorption table is heated to about 60 to 80 ° C., and the back from the adsorption table. The grind tape cannot be peeled off, and it becomes difficult to carry it to the next process by the built-in carrying mechanism.

From such a viewpoint, the tensile storage elastic modulus (E ′ ₈₀ ) of the substrate at 80 ° C. is preferably 8 to 200 MPa, more preferably 9 to 30 MPa. The tensile storage modulus (E ′ ₆₀ ) at 60 ° C. of the substrate is preferably 10 MPa or more, more preferably 20 to 150 MPa, and further preferably 30 to 110 MPa.

The tensile storage elastic modulus (E ′ ₈₀ ) of the substrate at ₈₀ ° C. and the tensile storage elastic modulus (E ′ ₆₀ ) of the substrate at 60 ° C. satisfy the relationship of (E ′ ₆₀ ) / (E ′ ₈₀ ) ≧ 2. It is preferable. The ratio of the tensile storage elastic modulus (E ′ ₈₀ ) to the tensile storage elastic modulus (E ′ ₆₀ ) [(E ′ ₆₀ ) / (E ′ ₈₀ )] is the tensile storage elastic modulus of the substrate from 60 ° C. to 80 ° C. It is an indicator of rate change. The tensile storage elastic modulus (E ′ ₈₀ ) of the substrate at ₈₀ ° C. and the tensile storage elastic modulus (E ′ ₆₀ ) of the substrate at 60 ° C. are in the relationship of 2 ≦ (E ′ ₆₀ ) / (E ′ ₈₀ ) ≦ 5. It is more preferable that the relationship 3 ≦ (E ′ ₆₀ ) / (E ′ ₈₀ ) ≦ 4.5 is satisfied, and 3.5 ≦ (E ′ ₆₀ ) / (E ′ ₈₀ ) ≦ 4. It is particularly preferable to satisfy the relationship .5.

By setting the ratio of the tensile storage elastic modulus (E ′ ₈₀ ) and the tensile storage elastic modulus (E ′ ₆₀ ) within the above range, the physical property change of the base material with respect to the temperature change due to heating of the adsorption table in the wafer back grinding apparatus can be achieved. Be controlled. As a result, the base material is prevented from being deformed in the temperature range and the close contact of the base material with the suction table is suppressed.

The substrate side of the laminate in which a PET film having a thickness of 75 μm, an adhesive layer having a thickness of 20 μm, and a substrate for a back grind tape having a thickness of 50 μm is laminated is placed on an adsorption table heated to 80 ° C. at an adsorption pressure of 85 kPa. After adsorbing and holding for a minute, the adhesive force between the substrate and the adsorption table when peeling the laminate at a peeling angle of 30 ° and a peeling speed of 300 mm / min with respect to the adsorption table is preferably 1 N or less, more preferably 0.2 to 0.8N, more preferably 0.3 to 0.5N. By making the adhesive force of the base material within the above range, the base material is excellent in peelability from the adsorption table.
The measurement method of the adhesion strength of the substrate is derived from the peeling behavior at the interface between the back grind tape 10 and the suction table 20 shown in FIG. As shown in FIG. 7, when the adhesive sheet 2 is adsorbed by the transfer arm 4 and the laminated body of the back grind tape 10 and the wafer 1 is lifted from the adsorption table 20, the laminated body bends, and the back grind tape 10 and the adsorption table. The angle of the peeling surface with respect to 20 (peeling angle α) is an acute angle. The inventors pay attention to the fact that the peeling angle of the back grind tape with respect to the suction table is about 30 °, and set pseudo conditions for the peeling behavior shown in FIG. It was measured. Although a specific measuring method will be described later, the “semiconductor wafer 1” shown in FIG. 7 is replaced with a “PET film”, and the suction table is subjected to predetermined conditions (heating temperature, suction pressure, suction time, peeling speed). The adhesion of the substrate was measured. The present inventors have found that the peelability of the substrate from the suction table is further improved by setting the adhesion of the substrate to a predetermined range.

The thickness of the substrate is not particularly limited, but is preferably 100 μm or less, more preferably 30 to 80 μm, and further preferably 40 to 60 μm. By setting the thickness of the base material within the above range, the stress during back grinding can be moderated appropriately.

Further, at least one surface of the base material may be subjected to an adhesion treatment such as a corona treatment in order to improve the adhesion with the pressure-sensitive adhesive layer described later. Moreover, you may laminate | stack an easily bonding layer on the base-material surface of the side which laminates | stacks an adhesive layer.

Although it does not specifically limit as a composition for easy-adhesion layer formation which forms an easy-adhesion layer, For example, the composition containing a polyester-type resin, a urethane-type resin, a polyester urethane-type resin, an acrylic resin etc. is mentioned. The easy-adhesion layer forming composition may contain a crosslinking agent, a photopolymerization initiator, an antioxidant, a softening agent (plasticizer), a filler, an antirust agent, a pigment, a dye, and the like, if necessary. Good.
The thickness of the easy adhesion layer is preferably 0.01 to 10 μm, more preferably 0.03 to 5 μm. In addition, since the thickness of an easily bonding layer is small with respect to the thickness of a base material, and a material is also soft, the influence which it has on the said physical properties, such as a tensile storage elastic modulus ( _E'80 ), is small. The storage elastic modulus (E ′ ₈₀ ) is substantially the same as the tensile storage elastic modulus (E ′ ₈₀ ) of the base material alone even when the easy-adhesion layer is provided.

The composition for forming a base layer containing the urethane (meth) acrylate (a1) and the polymerizable compound (a2) having an energy ray polymerizable group is cured by irradiation with energy rays. “Energy rays” refer to ultraviolet rays, electron beams, and the like, and preferably ultraviolet rays are used.
The base material which consists of the hardened | cured material of the said composition for base material layer formation is excellent in stress relaxation property and expandability. Further, the composition for forming a base material layer contains the above components (a1) and (a2), thereby controlling the above physical properties such as the tensile storage elastic modulus (E ′ ₈₀ ) of the base material within the above-described range. It becomes easy. In addition to the above components (a1) and (a2), the composition for forming a base layer is a polymerizable compound (a3) having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms. ) Is preferably contained. In addition to the above components (a1) and (a2), the composition for forming a base layer preferably contains a photopolymerization initiator, and has a functional group as long as the effects of the present invention are not impaired. You may contain a polymeric compound (a4), another additive, a resin component, etc.
Hereinafter, each component contained in the composition for base material layer formation is demonstrated in detail.

(Urethane (meth) acrylate (a1))
The urethane (meth) acrylate (a1) is a compound having at least a (meth) acryloyl group and a urethane bond, and has a property of being polymerized and cured by irradiation with energy rays. Urethane (meth) acrylate (a1) is an oligomer or a polymer.

The weight average molecular weight (Mw) of the component (a1) is preferably 1,000 to 100,000, more preferably 2,000 to 60,000, still more preferably 3,000 to 20,000. Further, the number of (meth) acryloyl groups (hereinafter also referred to as “functional group number”) in the component (a1) may be monofunctional, bifunctional, or trifunctional or more, but bifunctional is preferable.
The component (a1) can be obtained, for example, by reacting a (meth) acrylate having a hydroxyl group with a terminal isocyanate urethane prepolymer obtained by reacting a polyol compound and a polyvalent isocyanate compound. In addition, you may use a component (a1) individually or in combination of 2 or more types.

The polyol compound used as a raw material for the component (a1) is not particularly limited as long as it is a compound having two or more hydroxy groups. Specific examples of the polyol compound include alkylene diol, polyether type polyol, polyester type polyol, and polycarbonate type polyol. Among these, a polyester type polyol or a polycarbonate type polyol is preferable.
The polyol compound may be a bifunctional diol, a trifunctional triol, or a tetrafunctional or higher polyol, but is preferably a bifunctional diol, more preferably a polyester type diol or a polycarbonate type diol.

Examples of the polyvalent isocyanate compound include aliphatic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; isophorone diisocyanate, norbornane diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, dicyclohexylmethane-2 , 4'-diisocyanate, ω, ω'-diisocyanate dimethylcyclohexane, etc .; 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, tolidine diisocyanate, tetramethylene xylylene diisocyanate, naphthalene- And aromatic diisocyanates such as 1,5-diisocyanate.
Among these, isophorone diisocyanate, hexamethylene diisocyanate, and xylylene diisocyanate are preferable.

A urethane (meth) acrylate (a1) can be obtained by reacting a (meth) acrylate having a hydroxy group with a terminal isocyanate urethane prepolymer obtained by reacting the above-described polyol compound with a polyvalent isocyanate compound. The (meth) acrylate having a hydroxy group is not particularly limited as long as it is a compound having a hydroxy group and a (meth) acryloyl group in at least one molecule.

Examples of the (meth) acrylate having a hydroxy group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 5 -Hydroxyalkyl such as hydroxycyclooctyl (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate (Meth) acrylate; hydroxy group-containing (meth) acrylamide such as N-methylol (meth) acrylamide; vinyl alcohol, vinylphenol, bisphenol Reaction was of the diglycidyl ester of (meth) acrylic acid reaction is obtained; and the like.
Among these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

The conditions for reacting the terminal isocyanate urethane prepolymer and the (meth) acrylate having a hydroxy group are preferably the conditions of reacting at 60 to 100 ° C. for 1 to 4 hours in the presence of a solvent and a catalyst added as necessary. .
The content of the component (a1) in the base layer forming composition is preferably 10 to 70% by weight, more preferably 20 to 60%, based on the total amount (100% by weight) of the base layer forming composition. The mass is more preferably 25 to 55 mass%, particularly preferably 30 to 50 mass%.

(Polymerizable compound having energy ray polymerizable group (a2))
The polymerizable compound having an energy beam polymerizable group refers to a compound having three or more energy beam polymerizable groups. The energy beam polymerizable group is a functional group containing a carbon-carbon double bond, and examples thereof include a (meth) acryloyl group, a vinyl group, an allyl group, and a vinylbenzyl group. Two or more energy beam polymerizable groups may be combined. The energy ray polymerizable group in the polymerizable compound having an energy ray polymerizable group reacts with the (meth) acryloyl group in the component (a1), or the energy ray polymerizable groups in the component (a2) react with each other. Thus, a three-dimensional network structure (crosslinked structure) is formed. When the polymerizable compound (a2) having an energy beam polymerizable group is used, the cross-linked structure formed by energy beam irradiation is increased as compared with the case of using a compound containing one or two energy beam polymerizable groups. Therefore, the base material exhibits unique viscoelasticity, and it becomes easy to control the physical properties such as the tensile storage elastic modulus (E ′ ₈₀ ) within the above range.

From the above viewpoint, the number of energy ray polymerizable groups (the number of functional groups) in the polymerizable compound (a2) having an energy ray polymerizable group is preferably 3 to 10.

The weight average molecular weight of the component (a2) is preferably 200 to 3000, more preferably 300 to 800, and still more preferably 400 to 600.

Examples of the trifunctional component (a2) include trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate.
Examples of the tetrafunctional component (a2) include pentaerythritol tetra (meth) acrylate.
Examples of the pentafunctional component (a2) include dipentaerythritol penta (meth) acrylate.
Examples of the hexafunctional component (a2) include dipentaerythritol hexa (meth) acrylate.
In addition, you may use a component (a2) individually or in combination of 2 or more types.
Among these, dipentaerythritol hexa (meth) acrylate is preferable.

The content of the component (a2) in the base layer forming composition is preferably 1 to 50% by weight, more preferably 5 to 30%, based on the total amount (100% by weight) of the base layer forming composition. % By weight, more preferably 5 to 10% by weight.

(Polymerizable compound (a3) having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms)
Component (a3) is a polymerizable compound having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms, and is preferably a compound having at least one (meth) acryloyl group. By using the component (a3), the film formability of the obtained base layer forming composition can be improved. The number of (meth) acryloyl groups in component (a3) is more preferably 1 or 2.

The number of ring-forming atoms of the heterocyclic group contained in component (a3) is not particularly limited, but is preferably 3-6. Examples of the atoms forming the ring structure of the heterocyclic group include a carbon atom, a nitrogen atom, an oxygen atom, and a sulfur atom. In addition, the number of ring-forming atoms of the alicyclic group which component (a3) has is 6 to 20, preferably 6 to 18, more preferably 6 to 16, and still more preferably 7 to 12.
The number of ring-forming atoms means the number of atoms constituting the ring itself of a compound having a structure in which atoms are bonded in a ring, and atoms that do not form a ring (for example, hydrogen atoms bonded to atoms forming the ring) In addition, an atom included in a substituent when the ring is substituted with a substituent is not included in the number of ring-forming atoms.

Specific examples of the component (a3) include, for example, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate, cyclohexyl (meth) acrylate, Alicyclic group-containing (meth) acrylates such as adamantane (meth) acrylate; heterocyclic group-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, morpholine (meth) acrylate, and glycidyl (meth) acrylate; .

Although a component (a3) may be used independently, it is preferable to use in combination of 2 or more type. By using a combination of two or more components (a3), the tensile storage modulus (E _'80) to control the above properties such as easier, also, the film forming property of the base material layer-forming composition improves To do.
From such a viewpoint, it is more preferable to use a combination of two to three components (a3), and it is more preferable to use a combination of two components (a3). By using a component (a3) by said combination, the composition for base material layer formation becomes a simple structure, it is excellent in the productivity of the said composition, and can reduce cost.

Among the alicyclic group-containing (meth) acrylates, isobornyl (meth) acrylate is preferable, and among the heterocyclic group-containing (meth) acrylates, tetrahydrofurfuryl (meth) acrylate is preferable.

When the component (a3) is contained in the base layer forming composition, the content thereof is preferably 10 to 70% by weight, more preferably 10 to 70% by weight with respect to the total amount (100% by weight) of the base layer forming composition. The amount is preferably 20 to 60% by mass, more preferably 25 to 55% by mass.
Further, the content ratio [(a2) / (a3)] of the component (a2) and the component (a3) in the composition for forming a base layer is preferably 0.05 to 3.0, more preferably 0. 0.07 to 2.0, more preferably 0.08 to 1.0, and particularly preferably 0.1 to 0.5.

(Polymerizable compound having functional group (a4))
The composition for forming a base layer may contain a polymerizable compound (a4) having a functional group in addition to the components (a1) to (a3) as long as the effects of the present invention are not impaired.
Component (a4) is a polymerizable compound containing a functional group such as a hydroxyl group, an epoxy group, an amide group or an amino group, and more preferably a compound having at least one (meth) acryloyl group. The number of (meth) acryloyl groups in component (a4) is more preferably 1 or 2. The component (a4) is more preferably a compound having no alicyclic group or heterocyclic group having 6 to 20 ring atoms.
Component (a4) has good compatibility with component (a1), and it becomes easy to adjust the viscosity of the composition for forming a base layer to an appropriate range. Examples of the component (a4) include a hydroxyl group-containing (meth) acrylate, an epoxy group-containing compound, an amide group-containing compound, and an amino group-containing (meth) acrylate.

Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxy Examples include butyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, phenylhydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and the like.
Examples of the epoxy group-containing compound include methyl glycidyl (meth) acrylate and allyl glycidyl ether. Among these, epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate are exemplified. Is preferred.
Examples of amide group-containing compounds include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, N -Methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide and the like.
Examples of amino group-containing (meth) acrylates include primary amino group-containing (meth) acrylates, secondary amino group-containing (meth) acrylates, and tertiary amino group-containing (meth) acrylates.

Among these, a hydroxyl group-containing (meth) acrylate is preferable, and a hydroxyl group-containing (meth) acrylate having an aromatic ring such as phenylhydroxypropyl (meth) acrylate is more preferable.
In addition, you may use a component (a4) individually or in combination of 2 or more types.

The content of the component (a4) in the composition for forming a base layer is the total amount (100% by mass) of the composition for forming a base layer in order to improve the film formability of the composition for forming a base layer. On the other hand, it is preferably 0 to 40% by mass, more preferably 0 to 35% by mass, still more preferably 0 to 30% by mass, and particularly preferably 0 to 25% by mass.
Further, the content ratio [(a3) / (a4)] of the component (a3) and the component (a4) in the composition for forming a base layer is preferably 0.5 to 3.0, more preferably 1 It is 0.0 to 3.0, more preferably 1.3 to 3.0, and particularly preferably 1.5 to 2.8.

(Polymerizable compound (a5) other than components (a1) to (a4))
The composition for forming a base layer may contain other polymerizable compound (a5) other than the components (a1) to (a4) as long as the effects of the present invention are not impaired.
Examples of the component (a5) include alkyl (meth) acrylates having an alkyl group having 1 to 20 carbon atoms; styrene, hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, N-vinylformamide, N-vinylpyrrolidone, N-vinylcaprolactam, etc. Vinyl compounds: and the like. In addition, you may use a component (a5) individually or in combination of 2 or more types.

The content of the component (a5) in the composition for forming a base layer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, further preferably 0 to 5% by mass, and particularly preferably 0 to 2%. % By mass.

(Photopolymerization initiator)
In forming the base material, the base material layer-forming composition preferably further contains a photopolymerization initiator from the viewpoint of shortening the polymerization time by light irradiation and reducing the amount of light irradiation.
Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl phenyl sulfide, Tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloranthraquinone, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, eta Emissions, 1- [9-ethyl-6- (2-methylbenzoyl) -9H- carbazol-3-yl] -, 1- (o-acetyloxime) and the like.
These photopolymerization initiators can be used alone or in combination of two or more.
The content of the photopolymerization initiator in the composition for forming a base layer is preferably 0.05 to 15 masses with respect to 100 mass parts of the total amount of the components (a1) to (a5) having energy ray polymerizability. Part, more preferably 0.1 to 10 parts by weight, still more preferably 0.2 to 5 parts by weight.

(Other additives)
The composition for forming a base layer may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, and dyes. When these additives are blended, the content of each additive in the composition for forming a base layer is based on 100 parts by mass of the total amount of the components (a1) to (a5) having energy ray polymerizability. The amount is preferably 0.01 to 6 parts by mass, more preferably 0.1 to 3 parts by mass.

(Resin component)
The composition for forming a base layer may contain a resin component as long as the effects of the present invention are not impaired. Examples of the resin component include polyene / thiol resins, polyolefin resins such as polybutene, polybutadiene, and polymethylpentene, and thermoplastic resins such as styrene copolymers.
The content of these resin components in the composition for forming a base layer is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, still more preferably 0 to 5% by mass, and particularly preferably 0 to 2%. % By mass.

The base material of the present invention is obtained by polymerizing and curing a base material layer forming composition having the above composition by irradiation with energy rays. Therefore, the base material of this invention contains the polymerization unit derived from a component (a1) and the polymerization unit derived from a component (a2). Moreover, it is preferable that the base material of this invention contains the polymerization unit derived from a component (a3), and may contain the polymerization unit derived from a component (a4) and the polymerization unit derived from a component (a5). The content ratio of each polymerization unit in the substrate usually matches the ratio (preparation ratio) of each component constituting the substrate layer forming composition. For example, when the content of the component (a1) in the composition for forming a base layer is 10 to 70% by weight with respect to the total amount (100% by weight) of the composition for forming a base layer, the base is composed of the component (a1). 10) to 70% by mass of polymerized units derived from (1). In addition, when the content of the component (a2) in the composition for forming a base layer is 1 to 50% by weight with respect to the total amount (100% by weight) of the composition for forming a base layer, the base is composed of the component (a1). 1) to 50% by mass of polymerized units derived from (1).

The tensile storage elastic modulus (E ′ ₈₀ ), (E ′ ₆₀ ), the ratio of the tensile storage elastic modulus [(E ′ ₆₀ ) / (E ′ ₈₀ )] and the adhesive strength of the base material are, for example, those of component (a2) It can be controlled by the number of energy beam polymerizable groups and the content (% by mass) thereof.

[Manufacturing method of substrate]
There is no restriction | limiting in particular as a manufacturing method of the base material of this invention, It can manufacture by a well-known method. For example, a base material can be produced by applying and curing a composition for forming a base material layer on a release sheet, and removing the release sheet.

As a method of forming a substrate on a release sheet, a base layer forming composition is directly applied on a release sheet by a known coating method to form a coating film, and energy rays are applied to the coating film. A substrate can be formed by irradiation.

Examples of the method for applying the composition for forming a base layer include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure coating. Moreover, in order to improve applicability | paintability, you may mix | blend an organic solvent with respect to the composition for base material layer formation, and it may apply | coat on a peeling sheet as a solution form.

The curing of the coating film of the composition for forming a base layer by irradiation with energy rays may be performed by a single curing process or may be performed in a plurality of times. As an energy ray irradiated by the said hardening process, an ultraviolet-ray is preferable. When curing, the coating film of the composition for forming a base layer may be cured in an exposed state, but the exposed surface of the coating film is covered with another release sheet, and the coating film is not exposed. It is preferable to cure by irradiating energy rays.

[Adhesive tape]
The pressure-sensitive adhesive tape according to the present invention has a pressure-sensitive adhesive layer on at least one surface of the above-described substrate for back grind tape.
The pressure-sensitive adhesive layer is not particularly limited as long as it has an appropriate pressure-sensitive adhesive property at room temperature.

The thickness of the pressure-sensitive adhesive layer is preferably less than 40 μm, more preferably 5 to 35 μm, and even more preferably 10 to 30 μm. When the pressure-sensitive adhesive layer is made thin in this manner, the ratio of the low-rigidity portion in the pressure-sensitive adhesive tape can be reduced, so that chipping of the semiconductor chip that occurs during back surface grinding can be easily prevented.

The pressure-sensitive adhesive layer is formed of, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, etc., and an acrylic pressure-sensitive adhesive is preferable.
Moreover, an adhesive layer may be formed from an energy-beam curable adhesive. When the pressure-sensitive adhesive layer is formed of an energy ray-curable pressure-sensitive adhesive, it is possible to maintain a sufficient adhesiveness before curing by irradiation with energy rays and to set the peeling force to 1000 mN / 50 mm or less after curing. It becomes possible.

Hereinafter, although the specific example of an adhesive is explained in full detail, these are non-limiting illustrations, The adhesive layer in this invention should not be limitedly limited to these.
Examples of the energy ray curable adhesive include an energy ray curable adhesive containing an energy ray curable compound other than an adhesive resin in addition to a non-energy ray curable adhesive resin (also referred to as “adhesive resin I”). An agent composition (hereinafter also referred to as “X-type pressure-sensitive adhesive composition”) can be used. In addition, as an energy ray curable adhesive, an energy ray curable adhesive resin having an unsaturated group introduced into the side chain of a non-energy ray curable adhesive resin (hereinafter also referred to as “adhesive resin II”). An adhesive composition that is contained as a main component and does not contain an energy ray curable compound other than an adhesive resin (hereinafter also referred to as “Y-type adhesive composition”) may be used.

Furthermore, as the energy ray curable pressure sensitive adhesive, an X ray and Y type combined type, that is, an energy ray curable compound containing an energy ray curable compound other than the adhesive resin in addition to the energy ray curable adhesive resin II. An adhesive composition (hereinafter, also referred to as “XY-type adhesive composition”) may be used.

Further, as the pressure-sensitive adhesive, a non-energy ray-curable pressure-sensitive adhesive composition that does not cure even when irradiated with energy rays may be used. The non-energy ray curable adhesive composition contains at least the non-energy ray curable adhesive resin I, but does not contain the energy ray curable adhesive resin II and the energy ray curable compound described above. is there.

In the following description, “adhesive resin” is used as a term indicating one or both of the above-described adhesive resin I and adhesive resin II. Specific examples of the adhesive resin include acrylic resins, urethane resins, rubber resins, and silicone resins. Acrylic resins are preferable.
Hereinafter, the acrylic adhesive in which an acrylic resin is used as the adhesive resin will be described in more detail.

(Acrylic resin)
An acrylic polymer (b) is used for the acrylic resin. The acrylic polymer (b) is obtained by polymerizing a monomer containing at least an alkyl (meth) acrylate, and includes a structural unit derived from an alkyl (meth) acrylate. Examples of the alkyl (meth) acrylate include those having 1 to 20 carbon atoms in the alkyl group, and the alkyl group may be linear or branched. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) methacrylate, 2-ethylhexyl (meth) ) Acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate and the like. Alkyl (meth) acrylates may be used alone or in combination of two or more.

The acrylic polymer (b) preferably contains a structural unit derived from an alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer. The alkyl (meth) acrylate preferably has 4 to 12 carbon atoms, more preferably 4 to 6 carbon atoms. Moreover, it is preferable that the alkyl (meth) acrylate whose carbon number of an alkyl group is 4 or more is an alkyl acrylate.

In the acrylic polymer (b), the alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms is based on the total amount of monomers constituting the acrylic polymer (b) (hereinafter also simply referred to as “monomer total amount”). Thus, it is preferably 40 to 98% by mass, more preferably 45 to 95% by mass, and still more preferably 50 to 90% by mass.

In order to adjust the elastic modulus and adhesive properties of the pressure-sensitive adhesive layer in addition to the structural unit derived from alkyl (meth) acrylate having an alkyl group with 4 or more carbon atoms, the acrylic polymer (b) A copolymer containing a structural unit derived from an alkyl (meth) acrylate having 1 to 3 carbon atoms is preferred. The alkyl (meth) acrylate is preferably an alkyl (meth) acrylate having 1 or 2 carbon atoms, more preferably methyl (meth) acrylate, and most preferably methyl methacrylate. In the acrylic polymer (b), the alkyl (meth) acrylate having an alkyl group having 1 to 3 carbon atoms is preferably 1 to 30% by mass, more preferably 3 to 26% by mass, based on the total amount of monomers. More preferably, it is 6 to 22% by mass.

The acrylic polymer (b) preferably has a structural unit derived from a functional group-containing monomer in addition to the structural unit derived from the alkyl (meth) acrylate. Examples of the functional group of the functional group-containing monomer include a hydroxyl group, a carboxy group, an amino group, and an epoxy group. The functional group-containing monomer reacts with a crosslinking agent described later to become a crosslinking starting point, or reacts with an unsaturated group-containing compound to introduce an unsaturated group into the side chain of the acrylic polymer (b). Is possible.

Examples of the functional group-containing monomer include a hydroxyl group-containing monomer, a carboxy group-containing monomer, an amino group-containing monomer, and an epoxy group-containing monomer. These monomers may be used alone or in combination of two or more. Among these, a hydroxyl group-containing monomer and a carboxy group-containing monomer are preferable, and a hydroxyl group-containing monomer is more preferable.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 3-hydroxybutyl (meth) ) Acrylates, hydroxyalkyl (meth) acrylates such as 4-hydroxybutyl (meth) acrylate, and unsaturated alcohols such as vinyl alcohol and allyl alcohol.

Examples of the carboxy group-containing monomer include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid; ethylenically unsaturated dicarboxylic acids such as fumaric acid, itaconic acid, maleic acid and citraconic acid, and anhydrides thereof. , 2-carboxyethyl methacrylate and the like.

The functional group-containing monomer is preferably 1 to 35% by mass, more preferably 3 to 32% by mass, and still more preferably 6 to 30% by mass with respect to the total amount of monomers constituting the acrylic polymer (b).
In addition to the above, the acrylic polymer (b) is derived from a monomer copolymerizable with the above acrylic monomers such as styrene, α-methylstyrene, vinyl toluene, vinyl formate, vinyl acetate, acrylonitrile, acrylamide and the like. A structural unit may be included.

The acrylic polymer (b) can be used as a non-energy ray curable adhesive resin I (acrylic resin). In addition, as the energy ray-curable acrylic resin, a resin obtained by reacting a functional group of the acrylic polymer (b) with a compound having a photopolymerizable unsaturated group (also referred to as an unsaturated group-containing compound). Can be mentioned.

An unsaturated group containing compound is a compound which has both the substituent which can be couple | bonded with the functional group of an acrylic polymer (b), and a photopolymerizable unsaturated group. Examples of the photopolymerizable unsaturated group include a (meth) acryloyl group, a vinyl group, an allyl group, and a vinylbenzyl group, and a (meth) acryloyl group is preferable. Examples of the substituent that the unsaturated group-containing compound can bind to the functional group include an isocyanate group and a glycidyl group.
Therefore, examples of the unsaturated group-containing compound include (meth) acryloyloxyethyl isocyanate, (meth) acryloyl isocyanate, glycidyl (meth) acrylate, and the like.

In addition, the unsaturated group-containing compound preferably reacts with a part of the functional group of the acrylic polymer (b), specifically, 50 to 98 mol of the functional group of the acrylic polymer (b). % Is preferably reacted with an unsaturated group-containing compound, more preferably 55 to 93 mol%. As described above, in the energy ray-curable acrylic resin, a part of the functional group remains without reacting with the unsaturated group-containing compound, so that it is easily cross-linked by the cross-linking agent.
The weight average molecular weight (Mw) of the acrylic resin is preferably 300,000 to 1,600,000, more preferably 300,000 to 1,400,000, and still more preferably 300,000 to 1,200,000.

(Energy ray curable compound)
The energy ray-curable compound contained in the X-type or XY-type pressure-sensitive adhesive composition is preferably a monomer or oligomer having an unsaturated group in the molecule and capable of being polymerized and cured by irradiation with energy rays.
Examples of such energy ray curable compounds include trimethylolpropane tri (meth) acrylate, pentaerythritol (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4- Polyvalent (meth) acrylate monomers such as butylene glycol di (meth) acrylate, 1,6-hexanediol (meth) acrylate, urethane (meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, epoxy ( And oligomers such as (meth) acrylate.

Among these, urethane (meth) acrylate oligomers are preferable from the viewpoint of relatively high molecular weight and difficulty in reducing the tensile elastic modulus of the pressure-sensitive adhesive layer.
The molecular weight of the energy ray curable compound (weight average molecular weight in the case of an oligomer) is preferably 100 to 12000, more preferably 200 to 10,000, still more preferably 400 to 8000, and particularly preferably 600 to 6000.

The content of the energy ray-curable compound in the X-type pressure-sensitive adhesive composition is preferably 40 to 200 parts by mass, more preferably 50 to 150 parts by mass, and still more preferably 60 to 100 parts by mass with respect to 100 parts by mass of the adhesive resin. 90 parts by mass.
On the other hand, the content of the energy ray-curable compound in the XY type pressure-sensitive adhesive composition is preferably 1 to 30 parts by mass, more preferably 2 to 20 parts by mass, and still more preferably with respect to 100 parts by mass of the adhesive resin. Is 3 to 15 parts by mass. In the XY-type pressure-sensitive adhesive composition, the adhesive resin is energy ray curable, so even if the content of the energy ray curable compound is small, it is possible to sufficiently reduce the peeling force after irradiation with energy rays. It is.

(Crosslinking agent)
The pressure-sensitive adhesive composition preferably further contains a crosslinking agent. A crosslinking agent reacts with the functional group derived from the functional group monomer which adhesive resin has, for example, and bridge | crosslinks adhesive resins. Examples of the crosslinking agent include: tolylene diisocyanate, hexamethylene diisocyanate, and the like, and isocyanate-based crosslinking agents such as adducts thereof; epoxy-based crosslinking agents such as ethylene glycol glycidyl ether; hexa [1- (2-methyl) -aziridinyl ] Aziridine type crosslinking agents such as triphosphatriazine; Chelate type crosslinking agents such as aluminum chelate; These crosslinking agents may be used alone or in combination of two or more.

Among these, an isocyanate-based crosslinking agent is preferable from the viewpoints of increasing cohesive force and improving adhesive force, and availability.
The blending amount of the crosslinking agent is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 9 parts by mass, and still more preferably 0 with respect to 100 parts by mass of the adhesive resin from the viewpoint of promoting the crosslinking reaction. .05 to 8 parts by mass.

(Photopolymerization initiator)
Moreover, when an adhesive composition is energy-beam curable, it is preferable that an adhesive composition contains a photoinitiator further. By containing the photopolymerization initiator, the curing reaction of the pressure-sensitive adhesive composition can sufficiently proceed even with relatively low energy energy rays such as ultraviolet rays.

Examples of the photopolymerization initiator include benzoin compounds, acetophenone compounds, acylphosphinoxide compounds, titanocene compounds, thioxanthone compounds, peroxide compounds, and photosensitizers such as amines and quinones. Specifically, for example, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzylphenyl Such as sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, 8-chloroanthraquinone, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, etc. It is below.

These photopolymerization initiators may be used alone or in combination of two or more.
The blending amount of the photopolymerization initiator is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and further preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the adhesive resin. It is.

(Other additives)
The pressure-sensitive adhesive composition may contain other additives as long as the effects of the present invention are not impaired. Examples of other additives include antistatic agents, antioxidants, softeners (plasticizers), fillers, rust inhibitors, pigments, and dyes. When these additives are blended, the amount of the additives is preferably 0.01 to 6 parts by mass with respect to 100 parts by mass of the adhesive resin.

In addition, the pressure-sensitive adhesive composition may be further diluted with an organic solvent from the viewpoint of improving applicability to the substrate and a release sheet described later, and may be in the form of a solution of the pressure-sensitive adhesive composition.
Examples of the organic solvent include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, isopropanol and the like.
As these organic solvents, the organic solvent used at the time of the synthesis of the adhesive resin may be used as it is, or other than the organic solvent used at the time of synthesis so that the solution of the pressure-sensitive adhesive composition can be uniformly applied. One or more organic solvents may be added.

(Peeling sheet)
A release sheet may be attached to the surface of the adhesive tape. Specifically, the release sheet is attached to the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape. The release sheet is attached to the surface of the pressure-sensitive adhesive layer to protect the pressure-sensitive adhesive layer during transportation and storage. The release sheet is detachably attached to the adhesive tape, and is peeled off and removed from the adhesive tape before the adhesive tape is used (that is, before grinding the wafer back surface).
As the release sheet, a release sheet having at least one surface subjected to a release treatment is used, and specifically, a release sheet coated on the surface of the release sheet substrate may be used.

As the base for the release sheet, a resin film is preferable, and examples of the resin constituting the resin film include polyester resin films such as polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene naphthalate resin, polypropylene resin, polyethylene resin, and the like. Polyolefin resin and the like. Examples of the release agent include rubber elastomers such as silicone resins, olefin resins, isoprene resins, and butadiene resins, long chain alkyl resins, alkyd resins, and fluorine resins.
The thickness of the release sheet is not particularly limited, but is preferably 10 to 200 μm, more preferably 20 to 150 μm.

[Production method of adhesive tape]
There is no restriction | limiting in particular as a manufacturing method of the adhesive tape of this invention, It can manufacture by a well-known method.
For example, the adhesive sheet provided on the release sheet is bonded to the substrate provided by coating and curing the substrate layer forming composition on the release sheet, and the release sheet attached to the surface of the substrate is applied. By removing, an adhesive tape having a release sheet attached to the surface of the adhesive layer can be produced. The release sheet attached to the surface of the pressure-sensitive adhesive layer may be appropriately peeled off and removed before using the pressure-sensitive adhesive tape.

As a method of forming the pressure-sensitive adhesive layer on the release sheet, the pressure-sensitive adhesive (pressure-sensitive adhesive composition) is directly applied on the release sheet by a known application method, and the coating film is heated and dried, whereby the pressure-sensitive adhesive is obtained. A layer can be formed.

Alternatively, an adhesive (adhesive composition) may be directly applied to one side of the substrate to form an adhesive layer. Examples of the method for applying the pressure-sensitive adhesive include the spin coating method shown in the substrate manufacturing method.

[Method for Manufacturing Semiconductor Device]
The pressure-sensitive adhesive tape according to the present invention is preferably used in a method for manufacturing a semiconductor device including a step of heating a semiconductor wafer on a suction table.
As a non-limiting use example of the adhesive tape, a method for manufacturing a semiconductor device will be described more specifically below.

Specifically, the semiconductor device manufacturing method includes at least the following steps 1 to 3.
Step 1: Step of applying the above-mentioned adhesive tape to the surface of the semiconductor wafer Step 2: Step of grinding the semiconductor wafer having the adhesive tape attached to the surface from the back side Step 3: On the suction table, the semiconductor wafer after grinding The process of heating with

Hereafter, each process of the manufacturing method of the said semiconductor device is demonstrated in detail.
(Process 1)
In step 1, the adhesive tape according to the present invention is attached to the surface of the semiconductor wafer. The semiconductor wafer may be a silicon wafer, a gallium / arsenic wafer, or a glass wafer. The thickness of the semiconductor wafer before grinding is not particularly limited, but is usually about 500 to 1000 μm. A semiconductor wafer usually has a circuit formed on the surface thereof. Formation of the circuit on the wafer surface can be performed by various methods including conventionally used methods such as an etching method and a lift-off method.
The sticking of the adhesive tape to the semiconductor wafer surface is generally performed by an apparatus called a mounter, but is not particularly limited. The semiconductor wafer to which the adhesive tape is affixed is placed on the adsorption table via the adhesive tape, and is adsorbed and held. That is, the base material of the adhesive tape is in contact with the suction table.

(Process 2)
After step 1, the back surface of the semiconductor wafer is ground on the suction table to obtain a wafer having a predetermined thickness. The back surface grinding is performed by a known method using a grinder. After the back grinding process, a process of removing the crushed layer generated by grinding may be performed. The thickness of the semiconductor wafer after back grinding is not particularly limited, but is preferably about 10 to 400 μm, more preferably about 25 to 300 μm.
After the back grinding process, a ring frame concentric with the semiconductor wafer is arranged on the suction table.

(Process 3)
After step 2, the semiconductor wafer is heated on the suction table. More specifically, an adhesive sheet is attached to the back surface of the wafer while heating the semiconductor wafer on the suction table. Heat is propagated to the semiconductor wafer via the adhesive tape by heating the wafer pasting area on the suction table to about 60 to 80 ° C.
The method for attaching the adhesive sheet to the back surface of the semiconductor wafer is not particularly limited, and for example, the adhesive sheet is attached using a mounter. After attaching the long adhesive sheet to the semiconductor wafer and the ring frame, the long adhesive sheet may be cut into a ring frame shape, or an adhesive sheet having the same shape as the ring frame may be attached. “Adhesive sheet” refers to a film-like adhesive, a laminate of a film-like adhesive and a release sheet, a dicing tape and a film-like adhesive, which are used for adhering a semiconductor chip to a substrate or another chip. Or a dicing die bonding tape composed of an adhesive layer having both functions of a dicing tape and a die bonding tape and a release sheet. When using a film adhesive, a film adhesive having the same shape as the wafer is used.

Thereafter, the adhesive sheet is sucked by the transport arm and peeled off at the interface between the adhesive tape and the suction table. Then, a semiconductor device is manufactured through an adhesive tape peeling process, a dicing process, a die bonding process, and the like.
Since the base material of the present invention has heat resistance and does not adhere to the suction table even if the suction table is heated, it can be used effectively in a method for manufacturing a semiconductor device having this step. According to the pressure-sensitive adhesive tape of the present invention, since the adhesion of the base material to the suction table is prevented, the peelability of the pressure-sensitive adhesive tape from the suction table is excellent, and the wafer can be efficiently conveyed to the subsequent process.

As mentioned above, although the example which uses the adhesive tape of this invention for the back surface grinding process of a semiconductor wafer was demonstrated, the adhesive tape of this invention can also be used for the tip dicing method. The pre-dicing method refers to a method in which a groove having a predetermined depth is formed by a dicing blade from the front side of the wafer, and then grinding is performed from the back side of the wafer, and the wafer is separated into pieces by grinding. The pressure-sensitive adhesive tape of the present invention can also be used in a modification of the previous dicing method, in which a modified region is provided inside the wafer with a laser, and the wafer is separated into pieces by stress during grinding of the wafer back surface. Is possible. Furthermore, it can also be used to temporarily fix the workpiece during processing of glass, ceramics, or the like. It can also be used as various re-peeling adhesive tapes.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

The measurement method and evaluation method in the present invention are as follows.
[Tensile storage modulus]
For the base material produced in the examples or comparative examples, a dynamic viscoelasticity measuring device (manufactured by A & D, RHEOVIBRON DDV-01FP) was used according to ISO 6721-4 1994 (JIS K7244-4 1999). The tensile storage elastic modulus at 60 ° C. or 80 ° C. was determined at mode: tension, frequency: 1 Hz.

[Adhesion]
An acrylic pressure-sensitive adhesive (PK (manufactured by Lintec)) was applied to a PET film (trade name “SP-PET381031” manufactured by Lintec) and dried to form a pressure-sensitive adhesive layer having a thickness of 20 μm. The base material produced by the Example or the comparative example was laminated | stacked on the adhesive layer side of the said PET film, and it punched out to diameter 8 inches, and produced the sample for adhesive force measurement.

Next, a product name “Adwill D-210” manufactured by Lintec Corporation was cut into a width of 25 mm and a length of 100 mm to obtain a peeling tape.

Then, a peeling tape was attached to a 10 mm region from the outer edge of the sample toward the center of the sample. FIG. 4 is a perspective view of a state in which a peeling tape is attached to the outer edge portion of the sample for measuring the adhesion force. In FIG. 4, reference numeral 6 denotes a base material, reference numeral 5 denotes an adhesive layer, reference numeral 11 denotes a PET film, and reference numeral 30 denotes a peeling tape. FIG. 5 is a sectional view taken along line AA in FIG.

Then, the sample was placed on the suction table and sucked at a suction pressure of 85 kPa. In addition, the temperature of the sample sticking area | region in an adsorption table was 80 degreeC. Also, as a suction table, a ceramic suction table having a porous structure attached to RAD-2510 was mounted on a mounter “RAD-2510F / 12” manufactured by Lintec.
In this state, the sample was held by adsorption for 30 minutes.

Thereafter, a push-pull gauge is attached to the tip of the peeling tape, and as shown in FIG. 6, the push-pull gauge (not shown) is pulled against the suction table at a peeling angle of 30 ° and a peeling speed of 300 mm / min to suck the sample. Peeled from the table. The maximum peel force was measured for three samples, and the average value was defined as “adhesion strength”.

[Transportability]
The adhesive tapes produced in Examples and Comparative Examples were attached to the mirror side of a mirror wafer (diameter 8 inches, thickness 720 μm) using a laminator (product name: RAD-3510F / 12, manufactured by Lintec Corporation). The wafer to which the adhesive tape was attached was fixed so that the substrate of the adhesive tape was in contact with the suction table of a wafer back grinding machine (manufactured by DISCO, product name: DFP8760), and the wafer was ground to a thickness of 50 μm. Next, a ring frame was placed on the suction table concentrically with the wafer.

Then, the wafer pasting area on the suction table is heated to set the temperature of the wafer pasting area to 80 ° C., and then mounted on the ground surface and ring frame of the wafer using a mounter (product name: RAD-2700F / 12, manufactured by Lintec Corporation). Dicing die bonding tape was attached. The suction pressure of the suction table was 85 kPa.
In this state, the wafer on the adhesive tape was sucked and held for 30 minutes.

After that, the dicing / die bonding tape was sucked by the transfer arm, peeled off at the interface between the suction table and the adhesive tape, and the wafer was transferred. The case where peeling was satisfactorily carried out at the interface between the suction table and the adhesive tape and it could be conveyed was evaluated as “good”. On the other hand, the case where the base material of the adhesive tape was in close contact with the suction table and could not be conveyed was evaluated as “bad”.

In addition, all the mass parts of the following examples and comparative examples are solid content conversion.

[Example 1]
(1) Preparation of composition for forming substrate layer The terminal isocyanate urethane prepolymer obtained by reacting polycarbonate diol and isophorone diisocyanate is reacted with 2-hydroxyethyl acrylate to obtain a weight average molecular weight (Mw). About 5000 urethane acrylate oligomers were obtained.

50 parts by mass of the urethane acrylate oligomer synthesized above, 30 parts by mass of isobornyl acrylate (IBXA), 20 parts by mass of tetrahydrofurfuryl acrylate (THFA), and 10 parts by mass of dipentaerythritol hexaacrylate (DPHA) are blended. Furthermore, 0.3 part by mass of 2-hydroxy-2-methyl-1-phenyl-propan-1-one (product name “Irgacure 1173” manufactured by BASF Japan Ltd.) as a photopolymerization initiator, and ethanone, 1- [ 0.03 parts by mass of 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (o-acetyloxime) (product name “Irgacure OXE02” manufactured by BASF Japan Ltd.) It mix | blended and the composition for base material layer formation was prepared.

(2) Preparation of pressure-sensitive adhesive composition 84 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), 1 part by mass of acrylic acid (AA), and 5 parts by mass of 2-hydroxyethyl acrylate (2HEA) Was copolymerized to obtain an acrylic polymer (b) having a weight average molecular weight of about 300,000. 100 parts by mass of this acrylic polymer (b) is dissolved in an organic solvent (ethyl acetate: toluene = 1: 1) to obtain a 40% by mass solution, and a polyisocyanate compound (product name, manufactured by Nippon Polyurethane Industry Co., Ltd.) is used as a crosslinking agent. "Coronate L") 8 parts by mass (solid ratio) was added and mixed to prepare an adhesive composition.

(3) Preparation of base material The base layer-forming composition obtained above was applied to the release-treated surface of a release sheet (trade name “SP-PET 381031” manufactured by Lintec Corporation) to form a coating film. . Next, the coating film was irradiated with ultraviolet rays, and the coating film was semi-cured to form a substrate layer forming film having a thickness of 50 μm.
The above-mentioned ultraviolet irradiation uses a belt conveyor type ultraviolet irradiation device (manufactured by Eye Graphics, device name “US2-0801”) and a high-pressure mercury lamp (manufactured by Eye Graphics, device name “H08-L41”). The measurement was performed under irradiation conditions of a lamp height of 210 mm, an output of 80 W / cm, a light wavelength of 365 nm, an illuminance of 110 mW / cm ² and an irradiation amount of 50 mJ / cm ² .

Then, another release sheet is bonded to the surface of the formed base material layer forming film, and ultraviolet light is irradiated again to completely cure the base material layer forming film, and the release sheet laminated on both sides is removed. Thus, a substrate having a thickness of 50 μm was obtained. The above-mentioned ultraviolet irradiation uses the above-described ultraviolet irradiation apparatus and high-pressure mercury lamp, and the irradiation is performed at a lamp height of 175 mm, a converted output of 160 mW / cm, a light wavelength of 365 nm, an illuminance of 310 mW / cm ² , and an irradiation amount of 420 mJ / cm ² . Performed under conditions.

(4) Preparation of pressure-sensitive adhesive tape The pressure-sensitive adhesive composition is applied to the release-treated surface of a release sheet (trade name “SP-PET381031”, manufactured by Lintec Corporation), and heated and dried to give a pressure-sensitive adhesive having a thickness of 20 μm. An agent layer was formed. Then, the said adhesive layer was bonded together to one side of the said base material, and the adhesive tape was produced by removing the peeling sheet on an adhesive layer.

[Example 2]
A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that in the preparation of the composition for forming a base material layer, the DPHA content was changed to 6 parts by mass.

[Comparative Example 1]
A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that in the preparation of the composition for forming a base material layer, the DPHA content was changed to 0 parts by mass.

[Comparative Example 2]
A pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the amount of DPHA blended was changed to 2 parts by mass in the preparation of the base layer forming composition.

DESCRIPTION OF SYMBOLS 1 ... Wafer 2 ... Adhesive sheet 3 ... Ring frame 4 ... Transfer arm 10 ... Back grind tape 20 ... Suction table

Claims

A cured product of a composition for forming a base layer comprising a urethane (meth) acrylate and a polymerizable compound having an energy ray polymerizable group,
A substrate for back grind tape having a tensile storage elastic modulus at 80 ° C of 8 MPa or more.
The substrate side of the laminate in which a PET film having a thickness of 75 μm, an adhesive layer having a thickness of 20 μm, and a substrate for a back grind tape having a thickness of 50 μm is laminated is placed on an adsorption table heated to 80 ° C. at an adsorption pressure of 85 kPa. The adhesion force between the base material and the suction table when peeling the laminate at a peeling angle of 30 ° and a peeling speed of 300 mm / min with respect to the suction table is 1 N or less. Back grinding tape base material.
The substrate for back grind tape according to claim 1 or 2, wherein the number of energy ray polymerizable groups in the polymerizable compound having the energy ray polymerizable group is 3 or more.
4. The back grind tape according to claim 1, wherein the content of the polymerizable compound having an energy ray polymerizable group is 5 to 10% by mass with respect to the total amount of the base layer forming composition. Base material.
The substrate for back grind tape according to any one of claims 1 to 4, wherein the composition for forming a base layer contains a polymerizable compound having a heterocyclic group or an alicyclic group having 6 to 20 ring-forming atoms.
6. The substrate for back grind tape according to claim 5, wherein the composition for forming a substrate layer contains two or more polymerizable compounds having the heterocyclic group or an alicyclic group having 6 to 20 ring forming atoms.
7. An adhesive tape having an adhesive layer on at least one side of the substrate for back grind tape according to any one of claims 1 to 6.