WO2013039181A1

WO2013039181A1 - Polishing pad

Info

Publication number: WO2013039181A1
Application number: PCT/JP2012/073538
Authority: WO
Inventors: 陽平野呂; 奥田　良治; 誠司福田
Original assignee: 東レ株式会社
Priority date: 2011-09-15
Filing date: 2012-09-13
Publication date: 2013-03-21
Also published as: EP2757578A1; KR20140062095A; EP2757578A4; SG11201400614RA; TW201318766A; JPWO2013039181A1; US20140378035A1; CN103782372A

Abstract

A polishing pad for chemical mechanical polishing having at least a polishing layer, wherein the polishing surface of the polishing layer has a first groove and a second groove, and the first and the second grooves have side surfaces that are continuous with the polishing surface at the widthwise edges of each of the grooves. In the first groove, the angle between the polishing surface and the side surface continuous with the polishing surface is 105-150°on at least one widthwise edge of the groove. In the second groove, the angle between the polishing surface and the side surface continuous with the polishing surface is 60-105°on both widthwise edges of the groove.

Description

Polishing pad

The present invention relates to a polishing pad. More specifically, the present invention relates to a polishing pad that is preferably used for forming a flat surface in semiconductors, dielectric / metal composites, integrated circuits, and the like.

As the density of semiconductor devices increases, the importance of multilayer wiring and the accompanying interlayer insulation film formation, electrode formation of plugs, damascene, etc. is increasing. Accordingly, the importance of the flattening process of the interlayer insulating film and the metal film of the electrode is increasing. As an efficient technique for this flattening process, a polishing technique called CMP (Chemical Mechanical Polishing) is widely used.

Generally, a CMP apparatus includes a polishing head that holds a semiconductor wafer that is an object to be processed, a polishing pad for polishing the object to be processed, and a polishing surface plate that holds the polishing pad. A polishing technique called CMP is a technique for polishing a material to be polished while supplying slurry using a polishing pad having a polishing layer. Specifically, CMP polishing of a semiconductor wafer is performed by using a slurry to move a semiconductor wafer (hereinafter simply referred to as a wafer) and a polishing pad relative to each other to remove a protruding portion of a layer on the wafer surface. The surface layer is flattened.

CMP polishing has required characteristics such as local flatness of wafer, global flatness, prevention of defects, and high polishing rate. Therefore, in order to achieve these required characteristics, various ingenuity has been made with respect to the polishing pad groove configuration (groove pattern, groove cross-sectional shape, etc.), which is one of the major factors affecting polishing characteristics. Has been made.

For example, a technique is known in which the cross-sectional shape of a groove formed on the surface of the polishing layer is V-shaped or U-shaped, and the groove pattern is spiral or stitched to stabilize the polishing characteristics (Patent Document 1). reference).

In this technique, the corners in the cross-sectional shape of the grooves generate scratches on the surface of the wafer, or burr-like objects are formed in the corners due to dressing performed before and after polishing or during polishing in the cross-sectional shape. May cause scratches. As a technique for solving this problem, a technique of providing an inclined surface at the boundary between the polishing surface and the groove is also known (see Patent Documents 2 and 3).

JP 2001-212752 A JP 2010-45306 A JP 2004-186392 A

Here, the present inventors provide an inclined surface at a specific angle at the boundary between the polishing surface and the groove, so that a suction force acts between the wafer and the polishing pad, the polishing rate is increased, and in-plane uniformity is achieved. Found to be good. Since it is important to provide an inclined surface at the boundary between the polishing surface and the groove, this also applies to a groove having a V-shaped cross section, for example. In consideration of the manufacturing process, the cross-sectional shape of the groove is preferable because it is a simple figure.

However, when the cross-sectional shape of the groove is V-shaped, the present inventors have the functions of supplying and discharging the slurry at the end of the life of the polishing pad when the polishing pad is worn and the cross-sectional area of the groove is reduced. We have found a problem that polishing defects increase due to insufficientness.

In view of the problems of the prior art, the present invention reduces the function of supplying and discharging slurry even if the polishing pad wears according to the use of the polishing pad while maintaining a high polishing rate and good in-plane uniformity. It is an object of the present invention to provide a polishing pad in which polishing defects caused by this do not increase.

The present inventors use a polishing pad (for example, a V shape) having an inclined surface at a specific angle at the boundary between the polishing surface and the groove for increasing the polishing rate and improving in-plane uniformity, and a polishing pad. Accordingly, even if the polishing pad was worn out, it was thought that it could be eliminated by combining grooves for maintaining the slurry supply and discharge functions (for example, I-shaped or trapezoids close to I-shaped grooves).

Therefore, the present invention employs the following means in order to solve the above problems. That is, the polishing pad of the present invention is a polishing pad for chemical mechanical polishing having at least a polishing layer, and has a first groove and a second groove on a polishing surface of the polishing layer. Each of the two grooves has a side surface continuous with the polishing surface at an edge portion in each groove width direction, and the first groove has at least one of the edge surfaces in the groove width direction and the polishing surface. The angle formed by the side surface continuous with the polishing surface is greater than 105 degrees and 150 degrees or less, and the second groove is continuous with the polishing surface and the polishing surface at both of two edge portions in the groove width direction. The angle formed with the side surface is 60 degrees or more and 105 degrees or less.

According to the present invention, while maintaining a high polishing rate and good in-plane uniformity, the polishing pad wears as the polishing pad is used, and polishing without increasing polishing defects even if the slurry supply and discharge functions are reduced. A pad can be provided.

FIG. 1A is a diagram showing a cross-sectional shape (first example) of a first groove of a polishing pad according to an embodiment of the present invention. FIG. 1B is a diagram showing a cross-sectional shape (second example) of the first groove of the polishing pad according to the embodiment of the present invention. FIG. 1C is a diagram showing a cross-sectional shape (third example) of the first groove of the polishing pad according to the embodiment of the present invention. FIG. 1D is a diagram showing a cross-sectional shape (fourth example) of the first groove of the polishing pad according to the embodiment of the present invention. FIG. 2A is a diagram showing a cross-sectional shape (first example) of a second groove of the polishing pad according to the embodiment of the present invention. FIG. 2B is a diagram showing a cross-sectional shape (second example) of the second groove of the polishing pad according to the embodiment of the present invention. FIG. 2C is a diagram showing a cross-sectional shape (third example) of the second groove of the polishing pad according to the embodiment of the present invention. FIG. 2D is a diagram showing a cross-sectional shape (fourth example) of the second groove of the polishing pad according to the embodiment of the present invention. FIG. 2E is a diagram showing a cross-sectional shape (fifth example) of the second groove of the polishing pad according to the embodiment of the present invention. FIG. 2F is a diagram showing a cross-sectional shape (sixth example) of the second groove of the polishing pad according to the embodiment of the present invention. FIG. 3A is a cross-sectional view illustrating a configuration example (first example) of a unit unit including first and second grooves. FIG. 3B is a cross-sectional view illustrating a configuration example (second example) of a unit unit including first and second grooves. FIG. 3C is a cross-sectional view illustrating a configuration example (third example) of the unit unit including the first and second grooves. FIG. 3D is a cross-sectional view illustrating a configuration example (fourth example) of a unit unit including first and second grooves. FIG. 3E is a cross-sectional view illustrating a configuration example (fifth example) of a unit unit including first and second grooves. FIG. 3F is a cross-sectional view illustrating a configuration example (sixth example) of the unit unit including the first and second grooves. FIG. 3G is a cross-sectional view illustrating a configuration example (seventh example) of the unit unit including the first and second grooves. FIG. 3H is a cross-sectional view illustrating a configuration example (eighth example) of the unit unit including the first and second grooves. FIG. 3I is a cross-sectional view illustrating a configuration example (ninth example) of a unit unit including the first and second grooves. FIG. 4 is a diagram schematically showing an arrangement example of the first grooves on the polishing surface of the polishing pad according to the embodiment of the present invention.

Hereinafter, modes for carrying out the present invention will be described.
The polishing pad of the present invention is a polishing pad having at least a polishing layer, and has a groove A (first groove) and a groove B (second groove) on the polishing surface of the polishing layer. The groove A and the groove B have side surfaces that are continuous with the polishing surface at the edge portions in the groove width direction. In the groove A, at least one edge in the groove width direction, the angle formed by the polishing surface and the side surface continuous with the polishing surface is greater than 105 degrees and 150 degrees or less. In the groove B, the angle formed between the polishing surface and the side surface continuous with the polishing surface is 60 degrees or more and 105 degrees or less at both edge portions in the two groove width directions.

At least one edge of the groove A in the groove width direction has an angle between the polishing surface and the side surface continuous with the polishing surface that is greater than 105 degrees and less than or equal to 150 degrees, so that suction is performed between the wafer and the polishing pad. It is thought that the power works and the polishing rate increases. Further, it is considered that the suction force acts to bring the polishing pad into uniform contact with the wafer surface, thereby providing high in-plane uniformity to the wafer polishing rate.

If the angle formed between the polishing surface and the side surface continuous with the polishing surface is too large, the surface area of the polishing pad is reduced, and the cross-sectional area of the groove is too large, so that the slurry is excessively discharged and the polishing rate is reduced. Invite. On the other hand, if it is too small, the suction effect of the inclined groove side surface does not appear. For this reason, the angle formed between the polishing surface and the side surface continuous with the polishing surface must be greater than 105 degrees and 150 degrees or less, preferably 110 degrees or more, and preferably 115 degrees or more. More preferably, it is 120 degrees or more.

The groove A may have a bottom surface. The bottom surface is a surface continuous to the side opposite to the polishing surface with respect to the side surface continuous to the polishing surface, and is a surface connected to the opposite side surface. Note that the shape of the bottom surface is not particularly limited.

1A to 1D are diagrams showing specific examples of the cross-sectional shape of the groove A. FIG.
A groove A101 shown in FIG. 1A has a V-shaped cross-sectional shape. The groove A101 has two side surfaces 2 each continuous with the polishing surface 1 at the edge in the groove width direction. In the case shown in FIG. 1A, the angle θ _A formed by the polishing surface and the side surface continuous with the polishing surface is equal to each other at the two edge portions in the groove width direction, and the value is larger than 105 degrees and not larger than 150 degrees as described above. It is.
The groove A102 shown in FIG. 1B has a substantially U-shaped bottom surface 3 between two side surfaces 2.
A groove A103 shown in FIG. 1C has a trapezoidal cross-sectional shape, and has a bottom surface 4 parallel to the polishing surface 1 between two side surfaces 2.
A groove A104 shown in FIG. 1D has a recess 5 formed between two side surfaces 2 in a direction perpendicular to the polishing surface 1, and the bottom surface thereof is parallel to the polishing surface 1.

In addition, as for the side surface that is continuous with the polishing surface in the groove A, not only a straight line but also a curved line can be maintained if the angle formed with the polishing surface at the edge portion is greater than 105 degrees and 150 degrees or less even when the polishing pad is worn. A broken line, a wavy line, or a combination thereof may be used.

Here, the groove A constituting the polishing pad is not necessarily one type. For example, at least one of the edge portions in the groove width direction has a plurality of different cross-sectional shapes such that at least one of the angle formed between the polishing surface and the side surface continuous with the polishing surface is greater than 105 degrees and less than 150 degrees. It is also possible to constitute a polishing pad by combining grooves. From the viewpoint of in-plane uniformity, it is more preferable to configure the polishing pad with one type of groove A.

When polishing a polishing pad, it is essential to condition the pad surface using a conditioner with diamonds on a metal or ceramic base. By performing conditioning, the surface of the polishing pad can be maintained in a concavo-convex shape suitable for polishing, and stable polishing can be performed. However, the polishing layer is ground by conditioning, and the number of grooves decreases as the polishing progresses. When the cross-sectional area of the groove is reduced, the supply / discharge balance of the slurry is deteriorated, which may have adverse effects such as a decrease in polishing rate and an increase in defects.

For example, when the groove cross-sectional shape is only V-shaped, it has a sufficient slurry supply and discharge function at the initial stage of polishing. In some cases, the discharge is not performed sufficiently, and defects such as an increase in defects and a wafer adsorbing to the polishing pad may occur.

When only the groove A having the above-mentioned side surface is disposed on the entire pad surface, the cross-sectional area may decrease at the end of the polishing pad life, resulting in problems such as a decrease in polishing rate and an increase in defects. By providing the groove B for supplying and discharging the slurry, it is considered that a high polishing rate and in-plane uniformity can be maintained and stable polishing can be performed until the end of the polishing pad life.

Therefore, in order to stabilize the shape of the groove in the groove B, it is necessary that both the angle formed by the polishing surface and the “side surface continuous with the polishing surface of the groove B” be 60 degrees or more and 105 degrees or less. Yes, more preferably 80 degrees or more, and still more preferably 85 degrees or more. Further, it is more preferably 100 degrees or less, and further preferably 95 degrees or less.

The groove B preferably has a bottom surface. Note that the shape of the bottom surface of the groove B is not particularly limited.

2A to 2F are diagrams showing specific examples of the cross-sectional shape of the groove B. FIG.
A groove B201 shown in FIG. 2A has a rectangular cross-sectional shape. The groove B201 has two side surfaces 2 that are respectively continuous with the polishing surface 1 at the edge in the groove width direction. In the case shown in FIG. 2A, the angle θ _B formed between the polishing surface and the side surface continuous to the polishing surface is equal to each other at the two edge portions in the groove width direction, and the value is 90 degrees. Thus, the groove B201 has a rectangular cross-sectional shape, and the bottom surface 6 is parallel to the polishing surface 1.
A groove B202 shown in FIG. 2B has a substantially U-shaped bottom surface 7 between two side surfaces 2.
A groove B203 shown in FIG. 2C has a concave portion 8 formed with a narrow width between two side surfaces 2, and the bottom surface thereof is parallel to the polishing surface 1.
A groove B204 shown in FIG. 2D is formed continuously on each of the two side surfaces 2, and has a tapered inclined surface 9 inclined to the inner peripheral side, and a substantially U-shaped bottom surface 10 formed between the two inclined surfaces 9. Have
A groove B205 shown in FIG. 2E is formed continuously on each of the two side surfaces 2, and includes a tapered inclined surface 11 inclined to the inner peripheral side and a V-shaped bottom surface 12 formed between the two inclined surfaces 11. Have.
The groove B206 shown in FIG. 2F has a bottom surface 14 parallel to the polishing surface 1 between the two side surfaces 13. In the groove B206, the angle θ _B ′ between the polishing surface 1 and the side surface 2 continuous to the polishing surface 1 is an acute angle.

In addition, as for the side surface continuous with the polishing surface in the groove B, not only a straight line but also a curve, as long as the angle between the polishing pad and the polishing surface at the edge can be maintained at 60 ° or more and 105 ° or less. A broken line, a straight line having a plurality of bending points, a wavy line, or a combination thereof may be used.

Here, the groove B constituting the polishing pad does not have to be a single type of groove, and the polishing pad can be constituted by combining grooves having a plurality of different cross-sectional shapes. From the viewpoint of in-plane uniformity, one type of groove is preferable.

The groove formed on the polished surface is defined by the area ratio of the groove formed per area of the polished surface. The groove formed on the polished surface preferably has a groove area ratio per unit unit of 5% to 50%. In particular, the lower limit of the groove area ratio per unit unit is preferably 10% or more, and more preferably 15% or more. Further, the upper limit of the groove area ratio per unit unit is more preferably 45% or less, and further preferably 40% or less.

The unit unit is a unit formed by a combination of the groove A and the groove B arranged in parallel to each other, and the unit unit is repeatedly formed on the polishing surface, whereby a groove is formed on the entire polishing surface.

3A to 3I are diagrams showing a configuration example of a typical unit unit including the groove A and the groove B. FIG.
The unit unit 301 shown in FIG. 3A is composed of a combination of one groove A and three adjacent grooves B (array pattern: ABBB).
The unit unit 302 shown in FIG. 3B is a combination of one groove A and two adjacent grooves B (array pattern: ABB).
The unit unit 303 shown in FIG. 3C is a combination of two adjacent grooves A and three adjacent grooves B (array pattern: AABBBB).
The unit unit 304 shown in FIG. 3D includes one groove A and one groove B (array pattern: AB) adjacent to each other.
A unit unit 305 shown in FIG. 3E is formed by a combination of two adjacent grooves A and two adjacent grooves B (array pattern: AABB).
A unit 306 shown in FIG. 3F is formed by a combination of three adjacent grooves A and three adjacent grooves B (array pattern: AAABBB).
The unit 307 shown in FIG. 3G is a combination of three adjacent grooves A and two adjacent grooves B (array pattern: AAAB).
A unit unit 308 shown in FIG. 3H is a combination of two adjacent grooves A and one groove B (array pattern: AAB).
The unit unit 309 shown in FIG. 3I is composed of a combination of three adjacent grooves A and one groove B (array pattern: AAAB).

On the other hand, the area occupation ratio of the groove A per groove area is a ratio of the area of the groove A per area of the groove formed on the polishing surface, and the groove A per area of the groove formed on the polishing surface. Is preferably 30% or more and 90% or less, more preferably 40% or more, and further preferably 50% or more. Further, the area occupation ratio of the groove A per groove area is more preferably 80% or less, and further preferably 70% or less.

On the polishing layer surface of the polishing pad, grooves that can be taken by normal polishing pads such as lattice shape, dimple shape, spiral shape, concentric circle shape, etc. to suppress hydroplane phenomenon and to prevent the wafer and pad from sticking ( Grooves) may be provided, and combinations thereof are also preferably used, but a lattice shape is particularly preferable. The lattice shape is a shape in which lines are combined at right angles to a grid. In the lattice shape, when the vertical and horizontal grooves are equally spaced, when the vertical groove interval is narrower than the horizontal groove interval, or when the horizontal groove interval is narrower than the vertical groove interval Multiple cases are possible.

The groove A formed on the polishing surface of the polishing pad provides a high polishing rate and good in-plane uniformity as described above, but the balance between supply and discharge of slurry accompanying the reduction of the cross-sectional area at the end of life deteriorates. Lead to an increase in defects. Therefore, of the grooves formed on the polishing surface, the total length of the grooves A formed on the entire polishing surface is 10% or more and 90% or less of the total groove length of the grooves formed on the polishing surface. Preferably, it is 20% or more, more preferably 25% or more, still more preferably 30% or more, and particularly preferably 35% or more. Further, the total length of the grooves A among the grooves formed on the polished surface is more preferably 80% or less, further preferably 70% or less, and further preferably 60% or less. Is particularly preferably 55% or less.

When the ratio of the total groove length of the grooves A formed on the polishing surface to the total groove length of all the grooves is within the above range, a suction force acts between the wafer and the polishing pad, and the polishing rate Expresses the effect of rising. Further, in the method for forming a groove formed on the polishing surface of the polishing pad, it is possible to form the groove A so as to be concentrated at the center of the polishing pad and form the groove B in the remaining portion. In the case of a polishing pad having a circular polishing surface, the groove A is a region including two straight lines that pass through the center of the polishing pad and are orthogonal to each other, and the distance from at least one of the two straight lines is that of the polishing pad. It is preferably formed in a region that is 70% or less of the radius, more preferably if it is formed in a region that is 60% or less, further preferably if formed in a region that is 50% or less, and 40% or less. It is particularly preferable if it is formed in a region.

FIG. 4 is a diagram schematically showing an arrangement example of the grooves A on the polishing surface of the polishing pad. In the polishing pad 401 shown in FIG. 4, the groove A403 (indicated by a thick line) is an area including _two straight lines L ₁ and L ₂ passing through the center O of the polishing surface 402 on the circular polishing surface 402. The minimum distance from at least one of the two straight lines is 1/3 (about 33%) or less of the radius r. In addition, the broken line shown in FIG. 4 has shown groove | channel B404. Thus, when the XY lattice shape is applied as the groove shape, it is more preferable to disperse the grooves A403 in two orthogonal directions (X direction and Y direction) than to concentrate the grooves A403 in only one direction. .

When the grooves A and B are regularly arranged, for example, a polishing pad can be configured based on a unit unit as shown in any of FIGS. 3A to 3H. However, the ratio of the number of grooves A to the total number of grooves as a combination of grooves is not limited to the example.

The groove widths of the groove A and the groove B are preferably 0.1 mm or more and 10 mm or less, and more preferably 0.3 mm or more, because it is necessary to have a cross-sectional area capable of supplying and discharging the slurry. More preferably, it is 0.5 mm or more. Further, the groove width of the groove A and the groove B is more preferably 8 mm or less, and further preferably 5 mm or less.

The groove depths of the groove A and the groove B are preferably 0.2 mm or more and 4 mm or less, more preferably 0.3 mm or more, because it is necessary to ensure supply and discharge of slurry and a sufficient life. More preferably, it is 0.4 mm or more. Further, the groove depths of the groove A and the groove B are more preferably 3 mm or less, and further preferably 2 mm or less.

The thickness of the polishing layer is preferably 4.0 mm or less, more preferably 3.5 mm or less, as long as it is smaller than the distance from the upper surface of the surface plate of the polishing apparatus to the lower surface of the polishing head. It is more preferably 0 mm or less, and particularly preferably 2.5 mm or less.

In the present invention, the polishing layer constituting the polishing pad has a micro rubber A hardness of 70 degrees or more and a structure having closed cells to form a flat surface in a semiconductor, a dielectric / metal composite, an integrated circuit, or the like. Therefore, it is preferable. Although not particularly limited, materials for forming such a structure include polyethylene, polypropylene, polyester, polyurethane, polyurea, polyamide, polyvinyl chloride, polyacetal, polycarbonate, polymethyl methacrylate, polytetrafluoroethylene, epoxy resin, ABS resin, AS resin, phenol resin, melamine resin, “neoprene (registered trademark)” rubber, butadiene rubber, styrene butadiene rubber, ethylene propylene rubber, silicon rubber, fluororubber, and resins mainly composed of these. Two or more of these may be used. Even in such a resin, a material mainly composed of polyurethane is more preferable in that the closed cell diameter can be controlled relatively easily.

Polyurethane is a polymer synthesized by polyaddition reaction or polymerization reaction of polyisocyanate. Examples of the polyisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. However, the polyisocyanate is not limited thereto, and two or more of these may be used. The compound used as the reaction partner of the polyisocyanate is an active hydrogen-containing compound, that is, a compound containing two or more polyhydroxy groups or amino groups. The polyhydroxy group-containing compound is typically a polyol, and examples thereof include polyether polyol, polytetramethylene ether glycol, epoxy resin-modified polyol, polyester polyol, acrylic polyol, polybutadiene polyol, and silicone polyol. It may be used. It is preferable to determine the combination and optimum amount of polyisocyanate and polyol, catalyst, foaming agent, and foam stabilizer depending on the hardness, the cell diameter and the expansion ratio.

As a method of forming closed cells in these polyurethanes, the chemical foaming method is generally used by blending various foaming agents into the resin during polyurethane production, but it is cured after foaming the resin by mechanical stirring. The method of making it can also be used preferably.

The average cell diameter of the closed cells is preferably 20 μm or more, more preferably 30 μm or more from the viewpoint of holding the slurry on the pad surface. On the other hand, the average cell diameter of closed cells is preferably 150 μm or less, more preferably 140 μm or less, and still more preferably 130 μm or less, from the viewpoint of ensuring the flatness of local irregularities of the semiconductor substrate. The average bubble diameter is observed in a circular shape that is missing at the edge of the field among the bubbles observed in one field of view when the sample cross section is observed at 400 times magnification with a VK-8500 ultra-deep microscope manufactured by Keyence. For the circular bubbles excluding the generated bubbles, the equivalent circle diameter is measured from the cross-sectional area by an image processing apparatus, and the number average value is calculated.

A preferred embodiment of the polishing pad according to the present invention is a pad containing a polymer of a vinyl compound and polyurethane and having closed cells. Although the toughness and hardness can be increased only with the polymer from the vinyl compound, it is difficult to obtain a uniform polishing pad having closed cells. Polyurethane becomes brittle when its hardness is increased. By impregnating a polyurethane with a vinyl compound, a polishing pad containing closed cells and having high toughness and hardness can be obtained.

A vinyl compound is a compound having a polymerizable carbon-carbon double bond. Specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, isobutyl methacrylate, n-lauryl methacrylate, 2-hydroxyethyl methacrylate, 2 -Hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, ethylene glycol dimethacrylate, acrylic acid, methacrylic acid, fumaric acid, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, malein Acid, dimethyl maleate, diethyl maleate, dipropyl maleate Phenylmaleimide, cyclohexylmaleimide, isopropylmaleimide, acrylonitrile, acrylamide, vinyl chloride, vinylidene chloride, styrene, alpha-methyl styrene, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and the like. In addition, you may use 2 or more types of these as a vinyl compound.

Among the vinyl compounds described above, CH ₂ = CR ¹ COOR ² (R ¹ : methyl group or ethyl group, R ² : methyl group, ethyl group, propyl group or butyl group) is preferable. Among them, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and isobutyl methacrylate are easy to form closed cells in polyurethane, good in impregnation of monomers, easy to cure by polymerization, and vinyl compounds that have been cured by polymerization. The foamed structure containing the polymer and polyurethane is preferred because of its high hardness and good flattening characteristics.

Polymerization initiators preferably used for obtaining polymers of these vinyl compounds include azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), azobiscyclohexanecarbonitrile, benzoyl peroxide, lauroyl peroxide. Examples thereof include radical initiators such as oxide and isopropyl peroxydicarbonate. Two or more of these may be used. A redox polymerization initiator, for example, a combination of a peroxide and an amine can also be used.

As a method for impregnating a polyurethane with a vinyl compound, a method of immersing the polyurethane in a container containing a vinyl compound can be mentioned. In this case, it is also preferable to perform treatments such as heating, pressurization, decompression, stirring, shaking, and ultrasonic vibration for the purpose of increasing the impregnation rate.

The amount of vinyl compound impregnated in polyurethane should be determined by the type of vinyl compound and polyurethane used and the characteristics of the polishing pad to be produced. The content ratio of the polymer obtained from the vinyl compound in the body and the polyurethane is preferably 30/70 to 80/20 by weight. If the content ratio of the polymer obtained from the vinyl compound is 30/70 or more by weight, the hardness of the polishing pad can be sufficiently increased. Further, if the content ratio is 80/20 or less, the elasticity of the polishing layer can be sufficiently increased.

In addition, the polymer and polyurethane content obtained from the polymerized and cured vinyl compound in polyurethane can be measured by a pyrolysis gas chromatography / mass spectrometry method. As an apparatus that can be used in this method, a double shot pyrolyzer “PY-2010D” (manufactured by Frontier Laboratories) is used as a thermal decomposition apparatus, and “TRIO-1” (manufactured by VG) is used as a gas chromatograph / mass spectrometer. Can be mentioned.

In the present invention, from the viewpoint of flatness of local irregularities of the semiconductor substrate, it is preferable that the polymer phase obtained from the vinyl compound and the polyurethane phase are contained without being separated. This can be expressed quantitatively as follows: “The infrared spectrum when the polishing pad is observed with a micro-infrared spectrometer having a spot size of 50 μm is an infrared absorption peak of a polymer polymerized from a vinyl compound and polyurethane. And the infrared spectra at various locations are almost the same. " As a micro infrared spectroscope used here, IRμs manufactured by SPECTRA-TEC can be mentioned.

The polishing pad may contain various additives such as an abrasive, an antistatic agent, a lubricant, a stabilizer, and a dye for the purpose of improving characteristics.

In the present invention, the micro rubber A hardness of the polishing layer is a value evaluated by a micro rubber hardness meter MD-1 manufactured by Kobunshi Keiki Co., Ltd. The micro rubber A hardness meter MD-1 makes it possible to measure the hardness of thin and small objects, which are difficult to measure with a conventional hardness meter. The micro rubber A hardness tester MD-1 is designed and manufactured as a reduced model of about 1/5 of the spring type rubber hardness tester (durometer) A type. Therefore, the measurement conforms to the hardness of the spring type hardness tester A type. A value is obtained. A normal polishing pad cannot be evaluated with a spring type rubber hardness tester A type because the thickness of the polishing layer or hard layer is less than 5 mm. Therefore, in the present invention, the micro rubber A hardness of the polishing layer is evaluated by the micro rubber MD-1.

In the present invention, the hardness of the polishing layer is preferably 70 degrees or more, more preferably 80 degrees or more in terms of micro rubber A hardness, from the viewpoint of the flatness of local irregularities of the semiconductor substrate.

In the present invention, the density of the polishing layer is preferably 0.3 g / cm ³ or more, more preferably 0.6 g / cm ³ or more, and 0.65 g / cm ³ from the viewpoint of reducing local flatness defects and global steps. More preferably, it is cm ³ or more. On the other hand, the density of the polishing layer, from the viewpoint of reducing scratches, preferably 1.1 g / cm ³ or less, more preferably ^{0.9g / cm 3, 0.85g / cm} 3 or less is more preferred. The density of the polishing layer in the present invention is a value measured using a Harvard pycnometer (JIS R-3503 standard) and water as a medium.

The polishing pad in the present invention preferably has a cushion layer having a bulk modulus of 40 MPa or more and a tensile modulus of 1 MPa or more and 20 MPa or less from the viewpoint of improving in-plane uniformity. The volume elastic modulus is measured by applying an isotropic applied pressure to an object whose volume has been measured in advance and measuring the volume change. Based on the measurement result, the volume elastic modulus = applied pressure / (volume change / original Volume). In the present invention, it means the bulk modulus when a pressure of 0.04 to 0.14 MPa is applied to a sample at 23 ° C.

The bulk modulus in the present invention is measured by the following method. A sample piece and water at 23 ° C. are placed in a stainless steel measuring cell having an internal volume of about 40 mL, and a 0.5 mL borosilicate glass pipette (minimum scale 0.005 mL) is attached. Separately, a tube made of polyvinyl chloride resin (inner diameter 90 mmφ × 2000 mm, wall thickness 5 mm) is used as a pressure vessel, and the measurement cell in which the above sample piece is placed is placed therein. V1 is measured. Subsequently, without putting the sample piece into the measurement cell, nitrogen is pressurized with the pressure P and the volume change V0 is measured. A value obtained by dividing the pressure P by ΔV / Vi = (V1−V0) / Vi is calculated as the bulk modulus of the sample.

In the present invention, the volume elastic modulus of the cushion layer is preferably 40 MPa or more. By setting the bulk modulus to 40 MPa or more, the in-plane uniformity of the entire surface of the semiconductor substrate can be improved. Moreover, it is difficult to impregnate the cushion layer with slurry or water that flows into the holes penetrating the front and back surfaces of the polishing pad, and cushion characteristics can be maintained.

In the present invention, the tensile modulus is measured by applying a tensile stress in a dumbbell shape and measuring the tensile stress in a range of tensile strain (= change in tensile length / original length) from 0.01 to 0.03. Based on the measurement results, the tensile elastic modulus = ((tensile stress when the tensile strain is 0.03) − (tensile stress when the tensile strain is 0.01)) / 0.02. An example of a tensile stress measuring device is Tensilon Universal Tester RTM-100 manufactured by Orientec. The measurement conditions of the tensile stress are a dumbbell shape in which the test speed is 5 cm / min, the test piece shape is 5 mm wide, and the sample length is 50 mm.

In the present invention, the tensile elastic modulus of the cushion layer is preferably 1 MPa or more, and more preferably 1.2 MPa or more, from the viewpoint of in-plane uniformity over the entire surface of the semiconductor substrate. Further, the tensile elastic modulus of the cushion layer is preferably 20 MPa or less, and more preferably 10 MPa or less.

Examples of such a cushion layer include non-foamed elastomers such as natural rubber, nitrile rubber, “neoprene (registered trademark)” rubber, polybutadiene rubber, thermosetting polyurethane rubber, thermoplastic polyurethane rubber, and silicon rubber. However, it is not limited to these. The thickness of the cushion layer is preferably in the range of 0.1 to 2 mm. The thickness of the cushion layer is preferably 0.2 mm or more and more preferably 0.3 mm or more from the viewpoint of in-plane uniformity over the entire surface of the semiconductor substrate. In addition, the thickness of the cushion layer is preferably 2 mm or less, more preferably 1.75 mm or less from the viewpoint of local flatness.

Examples of means for attaching the polishing layer and the cushion layer include a double-sided tape or an adhesive.

The double-sided tape has a general configuration in which an adhesive layer is provided on both sides of a base material such as a nonwoven fabric or a film. Moreover, the polishing pad of this invention may be provided with the double-sided tape on the surface which adhere | attaches the platen of a cushion sheet. As such a double-sided tape, a tape having a general configuration in which an adhesive layer is provided on both surfaces of a substrate as described above can be used. As a base material, a nonwoven fabric, a film, etc. are mentioned, for example. In consideration of peeling from the platen after use of the polishing pad, it is preferable to use a film for the substrate.

Also, examples of the composition of the adhesive layer include rubber adhesives and acrylic adhesives. Considering the content of metal ions, an acrylic adhesive is preferable because the metal ion content is low. Also, the cushion sheet and the platen often have different compositions, and the composition of each adhesive layer of the double-sided tape can be made different to optimize the adhesive force to the cushion sheet and the platen.

Examples of the material to be polished in the present invention include the surface of an insulating layer or metal wiring formed on a semiconductor wafer. Examples of the insulating layer include an interlayer insulating film of metal wiring, a lower insulating film of metal wiring, and shallow trench isolation used for element isolation. Examples of the metal wiring include aluminum, tungsten, and copper, and structurally include damascene, dual damascene, and plug. When copper is used as the metal wiring, a barrier metal such as silicon nitride is also subject to polishing. As the insulating film, silicon oxide is currently mainstream, but a low dielectric constant insulating film is also used. The material to be polished can be used for polishing a magnetic head, hard disk, sapphire, etc. in addition to a semiconductor wafer.

The polishing method of the present invention is suitably used for forming a flat surface on glass, semiconductors, dielectric / metal composites, integrated circuits and the like.

Hereinafter, the details of the present invention will be described by way of examples. However, the present invention is not limited to the examples. The measurement was performed as follows.

<Inclination angle measurement>
A polishing pad with grooves formed on the polishing layer surface is sliced in the groove depth direction, and the cross section of the grooves is observed with an ultra-deep microscope of Keyence VK-8500 to determine the angle between the polishing surface and the side surface continuous with the polishing surface. It was measured. When the polishing pad was circular, the groove closest to the position of 50 mm, 150 mm and 250 mm from the center of the polishing pad was measured, and the average of these three points was taken as the inclination angle. When the polishing pad was not circular, the groove closest to the 50 mm, 150 mm, and 250 mm positions was measured from the intersection of the diagonal lines of the sheet toward one end, and the average of these three points was taken as the inclination angle.

<Average polishing rate measurement and in-plane uniformity>
Polishing was performed while detecting the end point under predetermined polishing conditions using a Mirror 3400 manufactured by Applied Materials. As the average polishing rate as the polishing characteristics, the polishing rate (nm / min) excluding the outermost periphery 10 mm of the 8-inch wafer was measured. The value obtained by dividing the standard deviation of the polishing rate by the difference between the maximum value and the minimum value of the polishing rate was defined as in-plane uniformity.

<Defect evaluation>
As an enhancement treatment, the polished wafer is immersed in 0.5 wt% hydrofluoric acid for 10 minutes, washed with water, and then washed with a mixed solution of 1.0 wt% ammonia solution and 1.0 wt% hydrogen peroxide solution. And washed with water and dried. For the cleaned wafer, the number of defects of 0.155 μm or more was counted using SP-1 manufactured by KLA-Tencor.

<Pad grinding speed>
The groove depth before and after polishing was measured by using a depth gauge (Digimatic type) manufactured by Mitutoyo Corporation, and the value obtained by dividing the groove reduction value by the disk usage time during evaluation was taken as the pad grinding speed.

<Ratio of the number of grooves A>
A polishing pad having grooves formed on the surface of the polishing surface was sliced in parallel with the grooves, and the number of grooves A and grooves B was measured. Furthermore, from the arrangement of the grooves A and B (cross-sectional view: FIG. 3) and the arrangement example of the grooves A and B (pattern diagram: FIG. 4), the total number of the grooves A and B is the number of the grooves A. Was taken as the ratio of the number of grooves A. The calculation formula is described below.
Ratio of number of grooves A = number of grooves A / (number of grooves A + number of grooves B) × 100 (%)

Hereinafter, Examples 1 to 11 and Comparative Examples 1 to 3 will be described.

Example 1
30 parts by weight of polypropylene glycol, 40 parts by weight of diphenylmethane diisocyanate, 0.5 parts by weight of water, 0.3 parts by weight of triethylamine, 1.7 parts by weight of a silicon foam stabilizer, and 0.09 parts by weight of tin octylate Mixing with a RIM molding machine, discharging into a mold and performing pressure molding, a foamed polyurethane sheet having a thickness of 2.6 mm (micro rubber A hardness: 42 degrees, density: 0.76 g / cm ³ , independent An average bubble diameter of bubbles was 34 μm).

The foamed polyurethane sheet was immersed in methyl methacrylate to which 0.2 part by weight of azobisisobutyronitrile was added for 60 minutes. Next, 15 parts by weight of polyvinyl alcohol “CP” (degree of polymerization: about 500, manufactured by Nacalai Tesque), 35 parts by weight of ethyl alcohol (special grade reagent, manufactured by Katayama Chemical), water 50 The foamed polyurethane sheet surface layer was coated with polyvinyl alcohol by being immersed in a solution consisting of parts by weight and then dried.

Next, the foamed polyurethane sheet was sandwiched between two glass plates via a vinyl chloride gasket and polymerized and cured by heating at 65 ° C. for 6 hours and at 120 ° C. for 3 hours. After releasing from between the glass plates and washing with water, vacuum drying was performed at 50 ° C. A polishing layer was prepared by slicing the hard foam sheet thus obtained to a thickness of 2.00 mm. The methyl methacrylate content in the polishing layer was 66% by weight. The D hardness of the polishing layer was 54 degrees, the density was 0.81 g / cm ³ , and the average cell diameter of closed cells was 45 μm.

The obtained hard foam sheet was ground on both sides to prepare a polishing layer having a thickness of 2 mm.

To the polishing layer obtained by the above method, a 0.3 mm product (volume elastic modulus = 65 MPa, tensile elastic modulus = 4 MPa) of 90 degree hardness of micro rubber A of thermoplastic polyurethane manufactured by Nippon Matai Co., Ltd. as a cushion layer, Using a roll coater, lamination was performed through an MA-6203 adhesive layer manufactured by Mitsui Chemicals Polyurethane Co., Ltd., and a double-sided tape 5604TDM manufactured by Sekisui Chemical Co., Ltd. was bonded to the back surface as a back tape.

Groove A with a groove width of 3.0 mm, a groove pitch of 15 mm, a cross-sectional shape V-shaped with a tilt angle θ _A of 135 degrees, a groove depth of 1.5 mm, a groove width of 1.5 mm, a groove pitch of 15 mm, and a groove depth of 1.5 mm The groove B having a rectangular cross section (inclination angle θ _B = 90 degrees) was alternately repeated (hereinafter referred to as pattern A), and formed into an XY lattice shape to obtain a polishing pad. The groove area ratio per unit unit of the groove A was 24.9%, and the area occupation ratio of the groove A per groove area was 73.7%.

The polishing pad obtained by the above method was attached to a surface plate of a polishing machine (“Mirra 3400” manufactured by Applied Materials Co., Ltd.). An 8-inch wafer of oxide film is set to retainer ring pressure = 41 kPa (6 psi), inner tube pressure = 28 kPa (4 psi), membrane pressure = 28 kPa (4 psi), platen rotation speed = 76 rpm, polishing head rotation speed = 75 rpm, and slurry (cabot SS-25) was supplied at a flow rate of 150 mL / min, and 100 sheets were polished with a Saesol dresser with a load of 17.6 N (4 lbf), a polishing time of 1 minute, and in-situ dressing for 30 seconds from the start of polishing. The average polishing rate of the 100th oxide film was 202 nm / min, and the in-plane uniformity was 11.8%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was very good at 331. The pad grinding rate during polishing was 1.01 μm / min.

(Example 2)
A groove on the polished surface is a V-shaped cross section having a groove width of 3.0 mm, a groove pitch of 15 mm, an inclination angle θ _A of 135 degrees, a groove depth of 1.5 mm, a groove width of 1.5 mm, a groove pitch of 15 mm, and a groove. It is composed of a rectangular cross-section groove B having a depth of 1.5 mm, and a combination of one groove A and two grooves B (hereinafter referred to as pattern B) is repeated over the entire area of the pad radius from the center of the polishing surface of the polishing pad. Polishing was carried out in the same manner as in Example 1 except that a lattice shape was formed. The groove area ratio per unit unit of the groove A was 20.7%, and the area occupation ratio of the groove A per groove area was 60.9%. The average polishing rate was 197 nm / min, and the in-plane uniformity was 9.0%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was as good as 211. The pad grinding rate during polishing was 1.21 μm / min.

(Example 3)
Two grooves _A having a groove width of 3.0 mm, a groove pitch of 15 mm, an inclination angle θ _A of 135 degrees and a groove depth of 1.5 mm on the surface of the polishing layer passing through the center of the polishing surface and perpendicular to each other. Are formed in an XY lattice shape in a region where the distance from at least one of the straight lines is 32% or less of the radius of the polished surface, and the groove width is 1.5 mm, the groove pitch is 15 mm, and the groove depth is 1. A groove B having a rectangular cross section of 5 mm was formed in an XY lattice shape in a region where the distance from the diameter exceeded 32% of the radius to form a polishing pad (hereinafter referred to as pattern C), and was the same as in Example 1. And polished. The groove area ratio per unit unit of the groove A was 23.1%, and the area occupation ratio of the groove A per groove area was 67.7%. The layout of the grooves is shown in FIG. The average polishing rate was 196 nm / min, and the in-plane uniformity was 10.9%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was 142, which was very good. The pad grinding rate during polishing was 1.34 μm / min.

(Example 4)
Polishing was performed in the same manner as in Example 1 except that the trapezoidal cross section with the inclination angle θ _A of the groove A on the polishing layer surface being 120 degrees. The groove area ratio per unit unit of the groove A was 16.5%, and the area occupation ratio of the groove A per groove area was 54.8%. The average polishing rate was 199 nm / min, and the in-plane uniformity was 6.0%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was very good at 155. The pad grinding rate during polishing was 1.14 μm / min.

(Example 5)
Polishing was performed in the same manner as in Example 4 except that the trapezoidal cross section with the inclination angle θ _A of the groove A on the polishing layer surface being 123 degrees was used. The groove area ratio per unit unit of the groove A was 28.3%, and the area occupation ratio of the groove A per groove area was 73.6%. The average polishing rate was 203 nm / min, and the in-plane uniformity was 8.4%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, 141 defects were found to be very good. The pad grinding rate during polishing was 1.32 μm / min.

(Example 6)
Polishing was performed in the same manner as in Example 4 except that the trapezoidal cross section with the inclination angle θ _B of the groove B on the surface of the polishing layer was 85 degrees. The groove area ratio per unit unit of the groove A was 30.2%, and the area occupation ratio of the groove A per groove area was 68.9%. The average polishing rate was 201 nm / min, and the in-plane uniformity was 9.1%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was very good at 139. The pad grinding rate during polishing was 1.11 μm / min.

(Example 7)
Polishing was performed in the same manner as in Example 3 except that the groove A on the surface of the polishing layer had a V-shaped cross section with an inclination angle θ _A of 120 degrees and the groove B had a trapezoidal cross section with an inclination angle θ _B of 85 degrees. The groove area ratio per unit unit of the groove A was 16.5%, and the area occupation ratio of the groove A per groove area was 54.8%. The average polishing rate was 200 nm / min, and the in-plane uniformity was 9.8%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, 211 defects were found to be very good. The pad grinding rate during polishing was 1.33 μm / min.

(Example 8)
Polishing was performed in the same manner as in Example 3 except that the groove A on the surface of the polishing layer had a V-shaped cross section with an inclination angle θ _A of 120 degrees, and the groove B had a trapezoidal cross section with an inclination angle θ _B of 95 degrees. The groove area ratio per unit unit of the groove A was 18.4%, and the area occupation ratio of the groove A per groove area was 49.0%. The average polishing rate was 209 nm / min, and the in-plane uniformity was 10.1%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, 109 defects were found to be very good. The pad grinding rate during polishing was 1.30 μm / min.

Example 9
Polishing was performed in the same manner as in Example 3 except that the groove A on the surface of the polishing layer had a V-shaped cross section with an inclination angle θ _A of 150 degrees. The groove area ratio per unit unit of the groove A was 34.6%, and the area occupation ratio of the groove A per groove area was 78.4%. The average polishing rate was 200 nm / min, and the in-plane uniformity was 9.9%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was 111, which was very good. The pad grinding rate during polishing was 1.41 μm / min.

(Example 10)
Polishing was performed in the same manner as in Example 3 except that the groove A on the surface of the polishing layer had a V-shaped cross section with an inclination angle θ _A of 150 degrees, and the groove B had a trapezoidal cross section with an inclination angle θ _B of 85 degrees. The groove area ratio per unit unit of the groove A was 34.6%, and the area occupation ratio of the groove A per groove area was 78.4%. The average polishing rate was 206 nm / min, and the in-plane uniformity was 10.0%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was very good at 153. The pad grinding rate during polishing was 1.44 μm / min.

(Example 11)
Polishing was performed in the same manner as in Example 3 except that the groove A on the surface of the polishing layer had a V-shaped cross section with an inclination angle θ _A of 150 degrees and the groove B had a trapezoidal cross section with an inclination angle θ _B of 95 degrees. The groove area ratio per unit unit of the groove A was 36.5%, and the area occupation ratio of the groove A per groove area was 74.3%. The average polishing rate was 200 nm / min, and the in-plane uniformity was 10.1%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, 134 defects were found to be very good. The pad grinding rate during polishing was 1.40 μm / min.

(Comparative Example 1)
Polishing was performed in the same manner as in Example 1 except that the groove on the surface of the polishing layer had only a rectangular cross section having a groove width of 1.5 mm, a groove pitch of 15 mm, and a groove depth of 1.5 mm. The average polishing rate was 180 nm / min, and the in-plane uniformity was 12.2%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was as good as 583. The pad grinding rate during polishing was 1.13 μm / min.

(Comparative Example 2)
The groove on the surface of the polishing layer was polished in the same manner as in Example 1 except that only the V-shaped cross section having a groove width of 3.0 mm, a groove pitch of 15 mm, a groove depth of 1.5 mm, and an inclination angle of 135 degrees was used. The average polishing rate was 217 nm / min, and the in-plane uniformity was 21.1%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, the number of defects was very good at 297. The pad grinding rate during polishing was 1.73 μm / min.

(Comparative Example 3)
Polishing was performed in the same manner as in Example 1 except that the polishing layer was 1.0 mm, and the grooves on the surface were only a V-shaped cross section having a groove width of 1.0 mm, a groove pitch of 15 mm, a groove depth of 0.5 mm, and an inclination angle of 135 degrees. did. The average polishing rate was 205 nm / min, and the in-plane uniformity was 18.3%.

When the polished wafer was counted for defects of 0.155 μm or more by the defect evaluation method, there were as many as 1521 defects. The pad grinding rate during polishing was 1.68 μm / min.

Table 1 shows the results obtained in Examples 1 to 11 and Comparative Examples 1 to 3 described above.

1, 402

Polishing surface

2, 13

Side surface

3, 4, 6, 7, 8, 10, 12, 14 Bottom surface 5 Recessed

portion

9, 11, 13

Slope

101, 102, 103, 104, 403 Groove A
201, 202, 203, 204, 205, 206, 404 Groove B
301, 302, 303, 304, 305, 306, 307, 308, 309 Unit unit 401 Polishing pad

Claims

A polishing pad for chemical mechanical polishing having at least a polishing layer,
Having a first groove and a second groove on the polishing surface of the polishing layer;
The first and second grooves have side surfaces that are continuous with the polishing surface at edge portions in the respective groove width directions,
In the first groove, at least one edge in the groove width direction, an angle formed by the polishing surface and a side surface continuous with the polishing surface is greater than 105 degrees and 150 degrees or less.
The polishing is characterized in that the second groove has an angle formed by the polishing surface and a side surface continuous to the polishing surface in both of two edge portions in the groove width direction of 60 degrees or more and 105 degrees or less. pad.
The polishing pad according to claim 1, wherein the second groove has a bottom surface.
The groove area ratio per unit unit is 5% or more and 50% or less, and the area occupation ratio of the first groove per groove area is 30% or more and 90% or less. Polishing pad.
The polishing pad according to any one of claims 1 to 3, wherein the first and second grooves are formed in a lattice shape.
The total groove length of the first groove formed on the polishing surface is 10% or more and 90% or less of the total groove length of the groove formed on the polishing surface. 5. The polishing pad according to 4.
The polishing surface is circular, and the first groove formed in the polishing surface is a region including two straight lines that pass through the center of the polishing surface and are orthogonal to each other, and the two straight lines 6. The polishing pad according to claim 4, wherein the polishing pad is formed in a region whose distance from at least one of the polishing surfaces is 70% or less of a radius of the polishing surface.
The first groove is characterized in that an angle formed by the polishing surface and a side surface continuous to the polishing surface is greater than 105 degrees and 150 degrees or less at both of the two edge portions in the groove width direction. The polishing pad according to any one of claims 4 to 6.