JP2012061559A - Tool for machining fine hole, method of producing the same, and method of processing polymer film - Google Patents

Abstract

The present invention provides a machining tool, a production method thereof, and a polymer film machining method for realizing high-efficiency and high-quality fine hole machining.
A hollow hollow needle made of metal by forming a fine through hole formed on a single crystal silicon substrate by a dry etching technique and laminating at least one or more kinds of metal films on the inner wall of the fine through hole. In addition, by using the fine hole drilling tool, a fine through hole having a minimum dimension of several μm to several tens of μm can be formed on the polymer film with high accuracy and high accuracy. Provide a method of processing with high quality and high efficiency.
[Selection] Figure 1

Description

  The present invention relates to a tool for drilling fine holes, a method for manufacturing the tool, and a method for processing a polymer film.

  As processing methods for forming fine through holes (through holes) in a polymer film, there are cutting processing, press processing (punching processing), chemical etching, and laser processing (for example, see Non-Patent Document 1). Cutting using a drill is an excellent method in that it can perform through-hole processing with a high aspect ratio (ratio of hole diameter to hole depth). However, in general, burrs are easily generated on the inlet side and the outlet side of the through hole, and the inner wall of the hole is also likely to be rough. In addition, there is a problem that the inner wall of the through hole is thermally altered by cutting heat generated during processing. Furthermore, since the processing is performed sequentially for each hole, there is a disadvantage that the productivity is low when a large number of holes need to be processed. In general, the minimum hole size of a through hole that can be processed is about 100 μm, and the cross-sectional shape of the through hole is limited to a circle.

  Punching using a punch (upper die) and a die (lower die) is an excellent productivity method capable of simultaneously forming a large number of through holes in a single process. However, it is necessary to align the punch and the die with high accuracy (generally, accuracy of about 1/100 mm), and it is necessary to manage the gap (clearance) between them to about several μm. For this reason, when the processing dimension becomes fine, it becomes difficult to manufacture punches and dies. In addition, there is a problem in quality that burrs and chips are generated on the outlet side of the through hole and that the inner wall of the hole tends to become rough. Generally, the minimum dimension of a through hole that can be processed is about several tens of μm.

  Chemical etching allows fine processing because the size of the through hole can be managed using a photolithographic method. However, in this construction method, corrosion (side etching) generally occurs in the lateral direction as well as in the depth direction with respect to the substrate surface, so that the inlet side of the hole is wider than the outlet side, resulting in a tapered hole cross section. Moreover, since a large amount of chemicals are used, it is not preferable from the viewpoint of protecting the global environment. Generally, it is used for processing through holes of about several tens of μm to several hundreds of μm.

  Laser machining is a method with the highest productivity among the hole machining methods currently in practical use when a large number of fine through holes with a diameter of 100 μm or less are machined (see Patent Document 1). However, there is a big problem that a resin residue (smear) is generated when a part of the processed material is generally reattached around the processed hole. For this reason, the process for removing a smear is needed separately, and the fall of productivity is caused. In general, the inner wall of the processed hole tends to be rough, and heat effects are unavoidable. Furthermore, the cross-sectional shape of the through hole is likely to be a tapered shape that tapers toward the outlet side. Generally, the minimum dimension of a through hole that can be processed is slightly less than 100 μm.

JP 2002-170905 A

Toshiro Higuchi et al., Micromechanical System Practical Technology Overview, Fuji Techno System, 1992

The present invention solves the above-mentioned problems of the prior art and provides a working tool, a method for producing the same, and a method for processing a polymer film for realizing high-efficiency and high-quality fine hole machining. The problems to be solved by the present invention are shown below.
1) To provide a through hole processing method capable of processing a fine through hole having a minimum dimension of several μm to several tens of μm in a polymer film with high efficiency. Also, simplify the manufacturing process that does not require post-processing after drilling.
2) Providing a high-quality through-hole machining method that suppresses the generation of burrs on the inlet and outlet sides of the through hole, improves the surface roughness of the inner wall of the machined hole, and reduces the thermal effect of the machined hole. To do.
3) To provide a through hole processing method having a cross-sectional shape substantially perpendicular to the surface of a substrate.
4) To provide a method of processing through-holes having not only a circular cross-sectional shape but also an arbitrary geometric shape and regularly arranged in an arbitrary size in a single process.
5) To provide a machining tool for realizing the above machining method. And a method for manufacturing the same.

  In order to solve the above-described problems, a micro-hole drilling tool according to the present invention forms a fine through-hole by a dry etching technique on a single crystal silicon substrate, and at least one or two or more kinds are formed on the inner wall of the fine through-hole. A metal hollow needle is formed by laminating metal films, and a part or all of the single crystal silicon is removed to expose the metal hollow needle.

  According to a second invention of a tool for drilling a fine hole, a metal plate-like base portion and the base portion are formed by laminating the metal film continuous to the inner wall of the fine through hole on either the front surface or the back surface of the substrate. It is characterized by forming a hollow needle standing upright.

According to a third invention of the micro-hole machining tool, the metal film is laminated after forming a silicon oxide film on the surface of single crystal silicon, so that the hollow needle has a silicon oxide film and a metal It is formed by the laminated structure of.

According to a fourth invention of the micro-hole machining tool, an amorphous carbon film containing only carbon as a main constituent element on the surface of the exposed portion of the hollow needle, or hydrogen, nitrogen, fluorine on the amorphous carbon film An additive-containing amorphous carbon film containing at least one of silicon and chromium is laminated.

The micro-hole drilling tool according to the present invention has a structure in which the hollow needle has a single or a plurality of standing on the single crystal silicon substrate or the plate-like base. It is a feature.

According to the present invention, there is provided a method for producing a micro-hole drilling tool comprising: a mold forming step of forming a micro-through hole mold on a single-crystal silicon substrate by a dry etching technique using plasma; and an inner wall of the micro-through hole. Including a needle forming step of forming one or more types of metal hollow needles by electrolytic plating, and a silicon removing step of removing a part or all of the single crystal silicon to expose the hollow needles. It is characterized by.

According to a second aspect of the method for producing a micro-hole drilling tool according to the present invention, the needle forming step is performed by performing electroless plating of metal on either the front surface or the back surface of the substrate. It comprises a step of forming a plate-like base and a hollow needle standing on the base.

According to a third aspect of the present invention, the needle forming step further includes a step of forming a silicon oxide film on the surface of the single crystal silicon and then performing electroless plating of metal. It is characterized by including.

According to a fourth aspect of the present invention, the needle forming step electroplats the same or different metal film on the metal film formed by electroless plating on the inner wall of the micro through hole. It is characterized by comprising the process of performing the process of laminating at least once.

According to a fifth invention of a method for producing a micro-hole drilling tool according to the present invention, an amorphous carbon film containing only carbon as a main constituent element on a surface of a portion where the hollow needle is exposed by the silicon removal step, or The method further includes a carbon film laminating step of laminating an amorphous carbon film containing an additive containing at least one of hydrogen, nitrogen, fluorine, silicon, and chromium on the amorphous carbon film.

Furthermore, in the processing method of the polymer film according to the present invention, one or both of the fine hole machining tool and the polymer film are heated to room temperature or higher, and the opening tip of the hollow needle of the fine hole machining tool is formed. A minute through hole is formed in the polymer film by applying a predetermined load to the tool for fine hole machining while abutting on the surface of the polymer film.

  The present invention relating to a micro-hole machining tool forms a micro through hole of several μm to several tens μm in single crystal silicon by MEMS (Micro Electro Mechanical Systems) technology, and the micro through hole By forming the hollow needle with the metal film laminated on the inner wall, a processing tool including a hollow needle having a minimum dimension of about several μm to several tens of μm can be obtained. In addition, the cross-sectional shape of the fine through-hole formed in the single crystal silicon is not limited to a circular shape, but the cross-sectional shape of the hollow needle formed of the metal film is an arbitrary shape.

  Moreover, according to this invention concerning the manufacturing method of the tool for fine hole processing, the tool for processing which has the hollow needle of the said fine diameter can be produced. At this time, since the hollow needle is composed of a metal film laminated on the inner wall of the fine through hole provided in the single crystal silicon, the cross sectional shape of the hollow needle can be changed by appropriately changing the cross sectional shape of the fine through hole. Can be in any shape.

Furthermore, in this invention concerning the processing method of a polymer film, the highly efficient and high-quality fine hole processing to the polymer film which has the following characteristics is realizable by using the said fine hole processing tool.
1) A fine through hole having a minimum dimension of several μm to several tens of μm can be processed in a polymer film with high efficiency, and a manufacturing process that does not require a post-process after drilling can be simplified.
2) High quality that suppresses the occurrence of processing defects (burrs, chips, etc.) on the inlet and outlet sides of the through hole, improves the surface roughness of the inner wall of the hole, and reduces the thermal effect of the hole. Through hole processing becomes possible.
3) A through hole having a cross-sectional shape substantially perpendicular to the surface of the substrate can be formed.
4) It is possible to process through-holes having not only a circular cross-sectional shape but also an arbitrary geometric shape and regularly arranged in an arbitrary size in a single process.

It is the figure which showed one Embodiment of this invention concerning the tool for fine hole processing which consists of metal hollow needles, and its manufacturing process. FIG. 5 is a view showing a second embodiment of the present invention relating to a micro-hole drilling tool composed of a hollow needle having a laminated structure of a silicon oxide film and a metal, and a method for producing the tool. It is the photograph which showed the experimental example of the fine hole processing to a polymer film (polyimide film). (A) is a photograph of the inlet side of the through hole, and (b) is a photograph of the outlet side of the through hole. It is the photograph which showed the experiment example of the fine hole processing to a polymer film (polypropylene film). (A) is a photograph of the inlet side of the through hole, and (b) is a photograph of the outlet side of the through hole. It is the photograph which showed the experimental example of the fine hole processing to a polymer film (polypropylene film), and is a photograph of the chip formed by hole processing.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. For convenience of explanation, an embodiment related to a manufacturing method will be mainly described. However, what is manufactured by the manufacturing method is an embodiment of a tool for drilling fine holes.

FIG. 1 is a cross-sectional view showing a first embodiment according to a method for producing a fine hole drilling tool. First, silicon oxide films 12a and 12b are formed on both surfaces of a single crystal silicon substrate 11 (for example, a thickness of about several tens of μm to several hundreds of μm). As a method for forming the silicon oxide film, for example, thermal oxidation can be used. Next, by using the pattern of the photoresist 13 formed by photolithography as a mask, the silicon oxide film 12a on the upper surface is patterned by reactive ion etching (RIE), thereby forming a minute opening 14 (FIG. 1). (See (a)). For the patterning of the silicon oxide film 12a, for example, RIE using trifluoromethane (CHF ₃ ) gas can be used.

Next, deep etching (DRIE) of the single crystal silicon substrate 11 is performed using the two-layer structure of the photoresist 13 / silicon oxide film 12a as a mask, and is perpendicular to the substrate surface as shown in FIG. Thus, the fine through hole 15 having a high aspect ratio (ratio of hole diameter to hole depth) is formed. This is the mold forming process. The DRIE is one of dry etching techniques, in which a protective film formation (passivation) process using perfluorocyclobutane (C ₄ F ₈ ) gas and an etching process using sulfur hexafluoride (SF ₆ ) gas are alternately performed. It is a technique that can form a fine hole with a high aspect ratio in silicon by repeating the above. In the DRIE process, the photoresist 13 can usually be completely removed during etching, so that the photoresist 13 removal process is not necessary. However, when the photoresist 13 remains, dry etching using oxygen gas (O ₂ ashing), cleaning using a mixed solution of sulfuric acid and hydrogen peroxide (SPM cleaning), and an organic solvent such as acetone are used. A process for removing the resist by any one of the resist stripping methods may be added separately.

Thus, under the preferable conditions of the DRIE process, as shown in FIG. 1B, the silicon oxide film 12b formed on the lower surface can be simultaneously opened in the process, thereby forming the micro through hole 15. By doing so, the minute through-hole 15 can function as a mold. Depending on the size (hole diameter and hole depth) and shape of the minute through hole 15, the silicon oxide film 12a formed on the upper surface may be completely removed before the silicon oxide film 12b on the lower surface is opened. obtain. In such a case, a structure in which only the bottom surface silicon oxide film 12b is separately removed is added to form a structure in which the bottom surface portion of the fine hole of the single crystal silicon substrate 11 is penetrated. As a method for removing the silicon oxide film 12b, for example, RIE using CHF ₃ gas or wet etching using buffered hydrofluoric acid (BHF) or dilute hydrofluoric acid (DHF) can be applied. At this time, the silicon oxide film 12b on the lower surface may be either removed entirely or removed partially from the silicon oxide film located on the extension line of the fine hole.

  Next, a palladium (Pd) catalyst nucleus 16 necessary for performing electroless plating is applied to the single crystal silicon substrate 11 in which the minute through holes 15 are formed (see FIG. 1C). In this step, Pd catalyst nuclei 16 are imparted to the front surface (upper surface in the drawing) and back surface (lower surface in the drawing) of the single crystal silicon substrate 11 simultaneously with the inner wall surface of the micro through-hole 15 formed in the single crystal silicon substrate 11. The In the present embodiment, since the silicon oxide films 12a and 12b are laminated on the single crystal silicon on the front and back surfaces of the single crystal silicon substrate 11, Pd is accurately formed on the surfaces of the silicon oxide films 12a and 12b. The catalyst nucleus 16 is provided. In addition, when the adhesion between the metal film formed by electroless plating performed in the subsequent process and silicon becomes a problem, the single crystal silicon substrate 11 is formed before the step of applying the Pd catalyst nucleus 16 as necessary. Add a surface roughening process. When the hole diameter is large or the aspect ratio is small, a method such as sputtering is used to form the inner wall of the minute through-hole 15 and the surface on either the upper surface side or the lower surface side of the single crystal silicon substrate 11. There is also a method of forming a metal thin film such as titanium (Ti) or copper (Cu) as an adhesion layer. In particular, when a metal film is formed on one surface of the single crystal silicon substrate 11 by electroless plating, adhesion may be a problem and peeling may occur. In this case, the formation of the adhesion layer is effective.

Next, the Pd catalyst nuclei on at least one side of the Pd catalyst nuclei 16 formed on the front surface (upper surface in the drawing) and the back surface (lower surface in the drawing) of the single crystal silicon substrate 11 are completely removed. In this embodiment, an example in which only the Pd catalyst nucleus on the surface side of the single crystal silicon substrate 11 is removed is shown. As the Pd catalyst nucleus removal step, for example, RIE using CHF ₃ gas can be used. In the RIE process, the Pd catalyst nucleus can be removed simultaneously by etching the surface layer of the silicon oxide film 12a. On the other hand, the reason why the Pd catalyst nucleus applied to the side wall of the minute through hole 15 remains without being removed is because the etching rate is overwhelmingly higher on the upper surface side of the single crystal silicon substrate 11 irradiated with ions vertically. It is.

  Next, the metal film 17 is formed by electroless plating (see FIG. 1D). In the electroless plating step, the metal film 17 is not formed on the surface side of the single crystal silicon substrate 11 from which the Pd catalyst nuclei have been removed. Therefore, in the present embodiment, the metal film 17 can be selectively formed only on the inner wall of the minute through hole 15 and the back surface side of the single crystal silicon substrate 11. This is the needle forming process. Thus, by removing the Pd catalyst nucleus 16 applied to the surface of the single crystal silicon substrate 11, it is possible to selectively form the metal film 17 in the electroless plating process. This is the first feature of the present invention relating to the manufacturing method. For example, when a metal film is also formed on the surface side of the single crystal silicon substrate 11, a step of removing only the metal film is necessary, but removing only the metal film by dry etching There are problems such as low processing speed, which is very difficult. Further, in order to selectively remove the metal film by wet etching, there is a technical problem that it is difficult to mask the inner wall of the minute through hole 15.

Finally, after completely removing the silicon oxide film 12a formed on the upper surface, only the silicon is selectively removed from the surface (upper surface) side of the single crystal silicon substrate 11, thereby making the metal hollow needle 20 (hereinafter referred to as " (Abbreviated as “hollow needle”) (see FIG. 1 (e)). The process so far is referred to as a silicon removal process. As a method for removing silicon, wet etching using a tetramethylammonium hydroxide (TMAH) aqueous solution or dry etching using xenon difluoride (XeF ₂ ) gas can be used. However, although the former TMAH etching is preferable because a smooth silicon etching surface can be obtained, depending on the material of the metal film 17 to be formed, the metal film itself may be etched and may not be used. The latter XeF ₂ gas etching has a feature of hardly etching materials other than silicon, and can be applied to almost all cases regardless of the material of the metal film 17.

  As described above, according to the present embodiment of the method for manufacturing a tool for drilling fine holes, a laminated structure of a silicon plate-like base portion 18 and a metal plate-like base portion 19 (as will be described later, either one may be used. ) Can be provided with a fine hole machining tool 1 composed of a hollow needle 20 in which a single or a plurality are erected. The fine hole drilling tool 1 produced in this way is an embodiment of the present invention relating to a fine hole drilling tool. Here, in the present embodiment, the silicon oxide film 12b is laminated between the silicon plate-like base portion 18 and the metal plate-like base portion 19, but the silicon oxide film 12b is removed in the middle of the process. It is good also as a structure. Further, the silicon plate-like base portion 18 and the metal plate-like base portion 19 may serve as a base portion for holding the hollow needle 20 and do not necessarily have a laminated structure. For example, the hollow needle 20 may be supported only by the metal plate-like base portion 19, and if only the silicon plate-like base portion 18 has a mechanical strength that can withstand the drilling of the polymer film. It is not necessary to form the metal plate base 19. Alternatively, the metal plate-like base portion 19 is not necessarily required if a separately prepared holding jig is attached to reinforce the mechanical strength as the base portion that holds the hollow needle 20. On the contrary, if the holding jig separately produced is attached to the lower surface side (metal plate-like base portion 19) of the fine hole machining tool 1, the silicon plate-like base portion 18 is not necessarily required. The holding jig may be made of any material such as single crystal silicon, quartz, glass, metal, ceramics, and plastic. However, the holding jig may have a structure in which a hollow portion communicating with the hollow needle 20 is provided inside, and at least one outlet portion to the outside communicating with the hollow portion is provided. It is essential. That is, the hollow portion and the outlet are structures necessary for collecting chips formed when drilling a polymer film.

  Further, in the above-described embodiment relating to the method for manufacturing the tool for processing a fine hole, the hollow needle 20 is constituted by the metal film 17 laminated on the inner wall of the fine through hole 15 provided in the single crystal silicon substrate 11. By appropriately changing the pattern of the openings 14 and changing the cross-sectional shape of the micro through-hole 15, the cross-sectional shape of the hollow needle 20 can be changed to an arbitrary shape. This is the second feature of the present invention according to the method for producing the tool for drilling fine holes. Further, since the minimum dimension (the dimension of the cross section) of the hollow needle 20 is determined by the resolution of photolithography, the shape of the hollow needle 20 of several μm to several tens μm can be manufactured with high accuracy. Furthermore, the length of the hollow needle 20 can be appropriately changed to an arbitrary length depending on the thickness of the single crystal silicon substrate 11 to be used. However, the maximum length of the hollow needle 20 depends on the aspect ratio of the through hole that can be processed by DRIE. Since the aspect ratio of DRIE is usually about 30, for example, if the diameter of a hollow needle to be produced is 10 μm, the maximum length is about 300 μm. However, technological development of the DRIE technology is progressing steadily, and the hollow needle 20 having a higher aspect ratio can be produced in the future. Furthermore, if the micro-opening 14 is patterned using the electron beam lithography technique, the minimum dimension (cross-sectional dimension) of the hollow needle 20 can be made as small as about several hundred nm to 1 μm.

  Furthermore, in the present embodiment according to the method for manufacturing the tool for drilling fine holes, the material of the metal film 17 formed by electroless plating is nickel (Ni), cobalt (Co), copper (Cu), palladium (Pd), There is no limitation on the type of the metal as long as it is a metal that undergoes a plating reaction in an autocatalytic manner, such as tin (Sn), gold (Au), silver (Ag), or platinum (Pt). Further, not only the simple metal (single composition) but also an alloy may be used. Furthermore, metals that can be co-deposited with the metal simple substance or alloy, such as phosphorus (P), boron (B), tungsten (W), zinc (Zn), manganese (Mn), iron (Fe), sulfur (S), An alloy containing at least one of elements such as chromium (Cr) may be used. In particular, among the metal films, Ni-based alloy films or Ni films that are excellent in high hardness, corrosion resistance, wear resistance, fatigue strength, and the like are preferable from the viewpoint of durability as a tool for drilling a polymer film. For the purpose of reducing the friction coefficient and improving the wear resistance, a composite plating film obtained by eutecting the fine particles of polytetrafluoroethylene (PTFE) or fine particles of graphite on the Ni-based alloy film is also used as the metal film 17. it can.

  Furthermore, as a modification of the embodiment according to the method for producing a tool for drilling a fine hole, in the electroless plating step, not only one type of metal film 17 but also electroless plating of different types of metal films may be sequentially performed. It is also possible to produce a metal hollow needle having a laminated structure of different metals. For example, by forming a metal film with high chemical stability (such as a metal with low chemical affinity with the polymer film to be drilled), and then stacking different metal films with excellent mechanical strength Thus, it is possible to produce a hollow needle having improved surface chemical stability while maintaining the mechanical strength of the hollow needle. Furthermore, if necessary, in order to improve the adhesion between the two kinds of metal films and suppress the generation of thermal stress, one or more kinds of different metals can be separately laminated as an intermediate layer. As described above, the advantage that the hollow needle 20 can be formed into a laminated structure of two or more types of metal films by sequentially repeating electroless plating is the third feature of the present invention according to the method for manufacturing a microhole drilling tool. It has become.

  Furthermore, as another modified example, following the electroless plating step, it is possible to stack the same or different metal films by electroplating. For example, the thickness of the hollow needle can be increased in a short time by laminating the Ni film by electroplating with a high deposition rate after performing electroless Ni plating. Furthermore, an advantage of performing electroplating after electroless plating is that electroplating is selectively performed only on the surface of the metal film (conductor) formed in the electroless plating step. That is, no special masking process or unnecessary metal film removal process after electroplating is required, and the production method is excellent in productivity. The type of metal to be laminated is not limited as long as it can be deposited by electroplating. For example, metals such as Ni, Cr, Cu, Zn, Sn, Au, Ag, and Pt and alloys thereof can be used. Further, it is possible to form a laminated film of different metals by sequentially repeating electroplating. In the case of performing electroplating, a PR (Periodic Reverse) plating method (forward / reverse plating method) excellent in forming a uniform plating film in the fine holes is preferable. As described above, the advantage of being able to have a laminated structure of two or more kinds of metal films by repeating the step of electroplating the hollow needle 20 after electroless plating at least once is the method for producing a microhole drilling tool. This is the fourth feature of the present invention.

  As described above, according to the above-described embodiment, a single metal hollow needle formed by laminating one or two or more kinds of metal films is formed on a single crystal silicon plate base or metal plate base. Alternatively, it is possible to provide a tool for drilling a fine hole in which a plurality are erected and a method for manufacturing the tool. Furthermore, the size of the micro-hole drilling tool itself (corresponding to the area of a polymer film that can be processed in a lump) is the size of a single crystal silicon wafer that can be handled by a semiconductor manufacturing apparatus (such as a photolithography apparatus or dry etching apparatus). Limited. However, since the diameter of 12 inches (300 mm) is the mainstream in the semiconductor manufacturing process even at present, it is possible to provide the fine hole machining tool having a sufficient size for machining applications.

  Furthermore, in the above-described embodiment, the surface of the metal hollow needle has an amorphous carbon film containing only carbon as a main constituent element, or hydrogen, nitrogen, fluorine, silicon or chromium is added to the amorphous carbon film. An additive-containing amorphous carbon film containing at least one of them can be laminated. Providing a fine hole drilling tool comprising the metal hollow needle provided with excellent wear resistance and a low friction coefficient by including the carbon film (commonly called diamond-like carbon: DLC) lamination step, and a method for producing the same Can be provided.

  Next, a second embodiment of the invention relating to a method for producing a fine hole drilling tool will be described. In addition, since the same process as 1st embodiment is included, only a different process is demonstrated. FIG. 2 is a cross-sectional view of the present embodiment. The only difference from the first embodiment is that it includes a step of forming a silicon oxide film 30 on the surface of the micro through hole 15 by thermal oxidation after the micro through hole 15 is formed by DRIE (FIG. 2 ( b)). Note that, after the DRIE process, the thermal oxidation may be performed after the silicon oxide films 12a and 12b are completely removed (BHF etching or DHF etching) once.

  In the second embodiment described above, after one or more kinds of metal films 17 are stacked on the surface of the silicon oxide film 30 formed on at least the inner wall of the micro through-hole 15 (see FIG. 2D). Further, only silicon is selectively removed from the upper surface side of the single crystal silicon substrate 11. Palladium catalyst nuclei 16 are applied as a pre-process to the portion where the metal film 17 is laminated (see FIG. 2C), but at least leaving the palladium catalyst nuclei 16 of the minute through holes 15 to remove others, A metal film 17 can be laminated in the minute through hole 15. Through the above process, a hollow needle 31 having a laminated structure of the silicon oxide film 30 and the metal film 17 can be formed (see FIG. 2E). A hollow needle having a higher strength and a higher bending strength (an index of ease of folding) is obtained by forming the laminated structure of the metal film 17 having a high fracture toughness and the silicon oxide film 30 having a high compressive fracture strength by the manufacturing method. 31 can be formed.

  As described above, according to the invention of the second embodiment, the provision of the fine hole machining tool 40 composed of a single or a plurality of hollow needles having a laminated structure of a silicon oxide film and a metal, and a method for producing the tool are provided. can do.

  Furthermore, providing the DLC film laminating step on the surface of the hollow needle composed of a laminated structure of the silicon oxide film and metal, thereby providing a tool for drilling fine holes with excellent wear resistance and a low friction coefficient, And a manufacturing method thereof.

  Next, an embodiment of the present invention relating to a method for processing a polymer film will be described. In this embodiment, any one of the embodiments of the fine hole machining tool described above is used. Then, either one or both of the fine hole machining tool or the polymer film is heated to room temperature or higher, and the tip of the hollow needle of the fine hole machining tool is in contact with the surface of the polymer film, By applying a predetermined load to the fine hole machining tool, fine through holes can be formed in the polymer film. In addition, as the heating temperature at the time of processing, it is preferable that the temperature is higher than the glass transition point of the polymer film to be processed and not higher than the melting point. In the hole processing, a plurality of polymer films are laminated (a number of polymer films whose total thickness is equal to or greater than the length of the hollow needle) is pasted on the silicon substrate surface, and the fine hole processing tool is attached. The contact was made.

  FIG. 3 shows an experimental example in which micro-hole processing is performed on a polymer film (polyimide film: thickness of about 38 μm) using a micro-hole processing tool composed of a hollow needle. Through holes (16 holes, pitch 80 μm) with a diameter of about 30 μm were processed under the conditions of a heating temperature of 350 ° C., a load of 6 N, and a processing time of 60 s. As a result, no processing defects (burrs, chips, etc.) are observed on the inlet side and the outlet side of the through hole, the inner wall of the through hole is extremely smooth, and high-quality fine hole processing is realized. The average diameter of the through holes is 34.9 μm (standard deviation: 0.4 μm) on the inlet side and 34.1 μm (standard deviation: 0.5 μm) on the outlet side. The value is only 0.8 μm (at most 2 μm or less), and it can be seen that the cross-sectional shape of the through hole is substantially perpendicular to the surface of the polymer film. Further, the variation in the diameter of the processed hole is small, and the difference between the outer diameter of the hollow needle and the diameter of the through hole is 1.5 μm at the maximum, and extremely fine hole processing is realized.

  FIG. 4 shows another experimental example in which micro-hole processing is performed on a polymer film (polypropylene film: thickness of about 35 μm) using a micro-hole processing tool composed of a hollow needle. In the case of a polypropylene film having lower mechanical strength and thermal stability than the polyimide film, high-precision and high-quality through-hole processing can be realized even under a low temperature condition of 120 ° C. (load 6N, processing time 60s). It was. In the two experimental examples, a hollow needle having a single-layer structure of a silicon oxide film prepared for an experiment is used in order to confirm the processed state of the through hole in the polymer film. Since this silicon oxide film is a brittle material, it may be damaged during processing. In particular, the hollow needle sometimes breaks when the fine hole machining tool is pulled out from the polymer film after the through hole is formed. As is clear from these experimental results, the single layer structure of the silicon oxide film is not sufficient in terms of strength as a hollow needle used for a fine hole drilling tool. Therefore, according to the embodiment of the fine hole machining tool as already described, a fine hole machining tool composed of a metal hollow needle having high fracture toughness, or a high structure having a laminated structure of a metal film and a silicon oxide film. It is possible to provide a tool for drilling fine holes made of a hollow needle having high strength and high bending strength.

  FIG. 5 shows an example of chips obtained when fine holes are processed in a polypropylene film. It is the photograph which removed the outermost layer polypropylene film and observed the surface of the 2nd layer polypropylene film, after laminating | stacking three said polypropylene films and performing hole processing. Chips formed by through-hole processing of the outermost polypropylene film have a cylindrical shape as shown in the photograph. The chips (9 pieces) have a shape with dimensions almost the same as the inner diameter of the hollow needles (9 pieces) used. This means that the processing of the polymer film (plastic deformation and shear deformation) is the hollow shape. This means that the process is relatively easily performed in a limited area at the tip of the needle opening.

  As described above, the cross-sectional shape of the through-hole formed in the polymer film is substantially the same as the cross-sectional shape (outer diameter or outer dimension) of the hollow needle of the fine hole machining tool. It is done. Further, under suitable heating conditions and load conditions, almost no processing defects (burrs, burrs, etc.) are observed on both the inlet side and the outlet side of the through hole, and the surface properties of the inner wall of the processed hole are extremely smooth. High quality fine drilling can be realized. Moreover, the cross-sectional shape of the processed hole is also substantially perpendicular to the polymer film surface. The above features are superior to conventional cutting (drilling), pressing (punching), chemical etching, and laser processing. Furthermore, since the processing time does not depend on the number of holes, highly efficient processing can be realized. In addition, compared with cutting (drilling) or laser processing, the thermal effect of the processed hole can be greatly reduced.

  As described above, the micro-hole drilling tool used here is composed of a hollow needle, so the contact area at the machining point is smaller than that of a simple solid structure (cylindrical structure) tool, and the workpiece is machined. It is possible to cause shear deformation to an object efficiently. Moreover, the plastic deformation and the shear deformation of the polymer film are facilitated by processing under a suitable temperature condition of room temperature or higher. Furthermore, in the case of the solid structure, the chips are pushed downward and the escape place is lost, but in the case of the hollow structure, the chips rise inside the hollow needle, and from the root portion of the hollow needle. It can be recovered efficiently. That is, it is not necessary to release chips downward by a combination of a punch and a die as in the conventional press working (punching). For this reason, the process similar to the highly accurate alignment of the punch and die, which is a major problem in press working (punching), is not required by using the fine hole drilling tool. Further, if the pressure on the base side of the hollow needle is reduced by a vacuum pump or the like, chips can be recovered to the outside more efficiently. Furthermore, there is an advantage that strong adhesion between the tip of the hollow needle and the surface of the polymer film can be secured at the same time.

  In addition, according to this invention concerning the processing method of a polymer film, there is almost no restriction | limiting in the polymer film which can be processed. For example, as a thermoplastic polymer film, polyethylene, polypropylene, polystyrene, polyacrylate ester, polymethacrylate ester, polyacrylonitrile, cellulose acetate, polyethylene terephthalate (PET), polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride , Nylon, polymethylpentene, polyurethane and the like. Examples of the thermosetting polymer film include polyimide, epoxy resin, phenol resin, and urea resin. In addition, as the fluororesin film, polytetrafluoroethylene (PTFE), fluorinated ethylene propylene resin (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), polychlorotrifluoroethylene (PCTFE), ethylene -Tetrafluoroethylene copolymer (PETFE).

As described above, in this embodiment according to the method for processing a polymer film, by using any one type of micro-hole drilling tool provided in the present invention, high efficiency and High quality fine hole machining can be realized.
1) A fine through hole having a minimum dimension of several μm to several tens of μm can be efficiently processed in a polymer film, and a manufacturing process that does not require a post-process after the hole processing can be simplified.
2) High quality that suppresses the occurrence of processing defects (burrs, chips, etc.) on the inlet and outlet sides of the through hole, improves the surface roughness of the inner wall of the hole, and reduces the thermal effect of the hole. Through hole processing becomes possible.
3) A through hole having a cross-sectional shape substantially perpendicular to the surface of the substrate can be formed.
4) It is possible to process through-holes having not only a circular cross-sectional shape but also an arbitrary geometric shape and regularly arranged in an arbitrary size in a single process.

  Application examples of through-hole processing of the polymer film include a package, an inkjet head nozzle, and various filters. In addition, production of a porous film in which the hole shape and size are artificially controlled, and a through hole portion of the polymer film is filled with at least one of a polymer, metal, or ceramics that is different from the polymer film. It can also be applied as a new functional polymer film creation technology. Furthermore, since micro-hole processing can be performed on a polyimide film, a flexible wiring board (FPC) having a copper wiring pattern formed on both sides of a flexible polyimide film (FPC) or high density mounting (HDI) It can be applied to the formation of ultra-fine through-holes required for high definition and high density of multilayer printed wiring boards.

  As mentioned above, although embodiment of this invention was described, each said embodiment shows an example of this invention and is not limited to these.

DESCRIPTION OF SYMBOLS 1 Tool for fine hole processing 11 Single crystal silicon substrate 12a Silicon oxide film 12b Silicon oxide film 13 Photoresist 14 Micro opening 15 Micro through hole 16 Palladium catalyst nucleus 17 Metal film 18 Silicon plate base 19 Metal plate base 20 Metal Hollow needle 30 Silicon oxide film 31 Silicon oxide film / Metal hollow needle 40 Fine hole machining tool

Claims (11)

A fine through hole is formed on a single crystal silicon substrate by a dry etching technique, and at least one or two or more kinds of metal films are laminated on the inner wall of the fine through hole to form a metal hollow needle, A tool for drilling fine holes, wherein a part or all of single crystal silicon is removed to expose the metal hollow needle. The metal film continuous to the inner wall of the minute through hole is laminated on either the front surface or the back surface of the substrate to form a metal plate-like base portion and a hollow needle standing on the base portion. The fine hole drilling tool according to claim 1. 3. The metal film is formed by stacking a metal film after forming a silicon oxide film on a surface of single crystal silicon, and the hollow needle is formed by a stacked structure of a silicon oxide film and a metal. Tool for drilling fine holes. The surface of the exposed portion of the hollow needle is an amorphous carbon film containing only carbon as a main constituent element, or the amorphous carbon film is added with at least one of hydrogen, nitrogen, fluorine, silicon or chromium The tool for fine hole drilling according to any one of claims 1 to 3, wherein an object-containing amorphous carbon film is laminated. 5. The micro-hole drilling tool according to claim 1, wherein a single or a plurality of the hollow needles are erected on the single crystal silicon substrate or the plate-like base portion. A mold forming process for forming a micro-through hole mold on a single crystal silicon substrate by dry etching technology using plasma,
A needle forming step of forming one or more kinds of metal hollow needles on the inner wall of the micro through-hole by electroless plating of metal;
And a silicon removing step of removing a part or all of the single crystal silicon to expose the hollow needle. The needle forming step is a step of forming a metal plate-like base portion and a hollow needle standing on the base portion by performing electroless plating of metal on either the front surface or the back surface of the substrate. The method for producing a fine hole drilling tool according to claim 6. The method for producing a micro-hole drilling tool according to claim 6 or 7, wherein the needle forming step is a step in which a silicon oxide film is formed on the surface of the single crystal silicon and then electroless plating of metal is performed. The needle forming step further includes a step of performing at least one or more steps of laminating the same kind or different kind of metal film by electroplating on the metal film formed by electroless plating on the inner wall of the minute through hole. A method for producing a tool for drilling fine holes according to any one of claims 6 to 8. On the surface of the portion where the hollow needle is exposed by the silicon removal step, an amorphous carbon film containing only carbon as a main constituent element, or at least hydrogen, nitrogen, fluorine, silicon or chromium in the amorphous carbon film 10. The method for producing a fine hole drilling tool according to claim 6, further comprising a carbon film laminating step of laminating an additive-containing amorphous carbon film containing any one of them. 6. A method of processing a polymer film using the fine hole drilling tool according to claim 1, wherein one or both of the fine hole drill tool and the polymer film are heated to room temperature or higher. By applying a predetermined load to the fine hole processing tool while abutting the opening end of the hollow needle of the fine hole processing tool on the surface of the polymer film, fine through holes are formed in the polymer film. A method for processing a polymer film, comprising: