JP5315678B2 - Polishing pad manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method capable of preventing cambering of an obtained polishing pad, preventing air catch between a polishing layer and a cushion layer, obtaining sufficient adhesion force between the polishing layer and the cushion layer and further obtaining dust-proof effect during manufacturing in the manufacturing method for the polishing pad. <P>SOLUTION: In the manufacturing method for the polishing pad, the polishing layer is adhered to the cushion layer through an adhesive. The cushion layer comprises an elastomer and after a step for pressurizing/adhering the polishing layer onto an opposite surface of the cushion layer in which a peelable resin film is laminated/integrated on one surface through the adhesive, a step for peeling off/removing the resin film from the cushion layer is provided. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method of manufacturing a polishing pad that can be used in a process of planarizing a semiconductor substrate, a surface of an insulating layer formed on the semiconductor substrate, and a surface of a metal wiring.

  Large scale integrated circuits (LSIs) typified by semiconductor memories have been integrated year by year, and accordingly, the manufacturing technology of large scale integrated circuits has also been increased in density. Furthermore, with this increase in density, the number of stacked semiconductor device manufacturing locations has also increased. Due to the increase in the number of stacked layers, unevenness of the main surface of the semiconductor substrate caused by stacking, which has not been a problem in the past, has become a problem. For this reason, chemical mechanical polishing (CMP) technology is used to compensate for insufficient depth of focus at the time of exposure due to unevenness caused by lamination or to improve wiring density by flattening the through-hole portion. Planarization of the used semiconductor substrate has been studied (for example, Non-Patent Document 1).

  In general, a CMP apparatus includes a polishing head that holds a semiconductor substrate that is an object to be polished, a polishing pad that performs polishing of the object to be polished, and a polishing surface plate that holds the polishing pad. Then, the polishing process of the semiconductor substrate is performed by using a polishing slurry composed of an abrasive (abrasive grains) and a chemical solution to move the semiconductor substrate and the polishing pad relative to each other, thereby removing the protruding portion of the semiconductor substrate surface layer. The layer on the substrate surface is smoothed.

  As a typical polishing pad currently used in CMP, a polyurethane-impregnated nonwoven fabric, a soft foamed polyurethane, etc., which is a cushion layer, are bonded to a hard polyurethane having a fine foam structure (bubble diameter: about 30-50 μm), which is a polishing layer. Examples thereof include a combined two-layer polishing pad (for example, Patent Document 1, Non-Patent Document 2) and a polishing pad (for example, Patent Document 2) using a non-foamed elastomer for the cushion layer.

  When manufacturing these two-layer structure polishing pads, it is common to bond the polishing layer and the cushion layer via a double-sided tape or adhesive, using a laminator or roll press as the method. It is common to apply pressure while removing air at the interface between the polishing layer, the cushion layer and the adhesive. However, in the case of using a soft elastomer for the cushion layer, there is a problem that if the pressure applied during bonding is strong, the cushion layer is deformed and the pad after manufacturing is warped. A polishing pad for a semiconductor substrate has a large adverse effect on polishing characteristics such as polishing rate and in-plane uniformity, and therefore, it is necessary to prevent the occurrence of minute warpage. For this reason, measures such as reducing the pressure applied during bonding to such an extent that warpage does not occur are taken, but minute air remains on the interface between the polishing layer, cushion layer and adhesive (air biting). There was a problem that the adhesive force between the polishing layer and the cushion layer was lowered.

That is, the conventional manufacturing method of a polishing pad using an elastomer for the cushion layer is insufficient to satisfy all of the points of warping of the resulting polishing pad, prevention of air biting between the polishing layer and the cushion layer, and strengthening of the adhesive force. Met.
Nikkei Microdevices July 1994, pages 50-57 JP-A-6-21028 CMP Technology Group, Global Net Co., Ltd. (2006), pp. 478-481 Japanese Patent No. 3685066

Accordingly, as a result of intensive investigations to solve these problems, the present inventors have made a cushion in which a resin film that can be peeled off on one side of an elastomer is laminated and integrated by melting and extruding an elastomer material on the resin film. By applying a method of pressure-bonding the polishing layer to the opposite side of the layer with an adhesive and finally peeling off the resin film from the cushion layer, the rigidity of the resin film can It has been found that the deformation of the cushion layer is suppressed, and that it is possible to satisfy all of the warping of the polishing pad, the prevention of air biting between the polishing layer and the cushion layer, and the enhancement of adhesion. Furthermore, since one side of the cushion layer is in a state in which the peelable resin film is laminated and integrated until the end of the adhesion, it has been found that a dustproof effect can be obtained for the cushion layer being manufactured, and the present invention has been completed.

  An object of the present invention is to provide a polishing pad warpage obtained in a method for manufacturing a polishing pad that can be used in a process for planarizing a semiconductor substrate, a surface of an insulating layer formed on the semiconductor substrate, or a surface of a metal wiring. It is an object of the present invention to provide a manufacturing method that can prevent air biting between the polishing layer and the cushion layer, obtain a sufficient adhesive force between the polishing layer and the cushion layer, and obtain a dustproof effect during manufacturing.

In order to solve the above problems, the present invention has the following configuration.
“In the manufacturing method of the polishing pad that adheres the polishing layer to the cushion layer via an adhesive, the cushion layer is made of elastomer, and the resin film that can be peeled off on one side by melting and extruding the elastomer material on the resin film is laminated and integrated A method for producing a polishing pad, comprising a step of peeling and removing a resin film from a cushion layer after a step of pressure-bonding the polishing layer with an adhesive on the opposite surface of the cushion layer.

  INDUSTRIAL APPLICABILITY According to the present invention, in a method of manufacturing a polishing pad that can be used in a process of flattening a semiconductor substrate, a surface of an insulating layer formed on the semiconductor substrate, or a surface of a metal wiring, warping of the polishing pad and air biting obtained. Thus, it is possible to provide a production method in which sufficient adhesion between the polishing layer and the cushion layer can be obtained, and further, a dustproof effect during production can be obtained.

The manufacturing method of the polishing pad of the invention is a resin film for preventing warpage and air biting of the obtained polishing pad, ensuring sufficient adhesion between the polishing layer and the cushion layer, and obtaining a dustproof effect during manufacture. After the elastomer material is melt-extruded on the opposite side of the cushion layer made of an elastomer that is laminated and integrated with a resin film that can be peeled on one side, an abrasive layer is pressed and bonded via an adhesive, It is essential to include a step of peeling and removing the resin film.

  The resin film used in the present invention is not particularly limited as long as it can be laminated and integrated with an elastomer described later. Examples of the material include, but are not limited to, polyethylene, polypropylene, polyethylene terephthalate, polyamide, and laminates thereof. The thickness is not particularly limited, but is preferably 20 to 200 μm. If the thickness is less than 20 μm, the rigidity of the cushion layer tends to be poor due to low rigidity. If the thickness exceeds 200 μm, the rigidity is so high that it is difficult to handle the cushion layer with a roll (roll). Tends to decrease. The thickness is more preferably 50 to 150 μm. Moreover, there is no problem even if the surface of the film is subjected to a surface roughening treatment such as corona or plasma discharge treatment, sand blasting or embossing.

  In the present invention, a cushion layer made of an elastomer in which a peelable resin film is laminated and integrated means that a resin film and a cushion layer made of an elastomer are laminated, and a peeling force must be applied to the cushion layer made of a resin film or an elastomer. If they are not peeled off. For this reason, the one in which a cushion layer made of a resin film and an elastomer is simply overlapped is not included here. Further, the case where the resin film and the cushion layer made of elastomer are in close contact by static electricity is not included here.

  The peeling force between the cushion layer and the resin film is not particularly limited, but the 90 ° peeling force is preferably 50 to 1000 gf / 25 mm. If the 90 ° peeling force is less than 50 gf / 25 mm, the resin film is peeled off during pressure bonding, and the cushion layer deformation suppressing effect tends to be poor, and the cushion layer dustproof effect tends to decrease, and 1000 gf / 25 mm. Exceeding the thickness tends to make it difficult to remove the resin film from the cushion layer, and is not preferable because it may damage the polishing pad after bonding. It is more preferable that it is 70-700 gf / 25mm. The 90 ° peeling force is a value measured by the method described in JIS K6854-1.

  The cushion layer made of an elastomer in the present invention is not particularly limited. Examples of the material include, but are not limited to, natural rubber, nitrile rubber, neoprene (registered trademark) rubber, polybutadiene rubber, chloroprene rubber, thermoplastic polyurethane rubber, thermosetting polyurethane rubber, silicone rubber, and fluorine rubber. It is not a thing. Among these, the thermoplastic polyurethane rubber is preferably used because it can obtain a product having excellent thickness accuracy and can be molded without using a release agent and has excellent adhesiveness. The thermoplastic polyurethane is composed of a soft segment exhibiting rubber-like elasticity and a hard segment serving as a knot of a three-dimensional rope. The thermoplastic polyurethane exhibits rubber elasticity at room temperature and is plasticized at high temperature, so that it can be extruded. Specifically, it is an elastomer in which the hard segment is a polyurethane block polymer having a urethane bond, and the soft segment is polyester or polyether. These cushion layer materials may contain various additives such as antistatic agents, lubricants, stabilizers, dyes, and other resins in order to obtain necessary properties.

  The structure of the cushion layer of the present invention may be either foamed or non-foamed, but is preferably non-foamed because of good in-plane uniformity in the initial stage of polishing.

  The hardness of the cushion layer is not particularly limited, but a micro rubber A hardness of 50 to 80 is preferable because of excellent in-plane uniformity of polishing. When the micro rubber A hardness is less than 50, the planarization property tends to deteriorate during polishing, and when it exceeds 80, the in-plane uniformity deteriorates during polishing. In addition, the micro rubber A hardness in the present invention refers to a value measured with a micro rubber hardness meter MD-1 manufactured by Kobunshi Keiki Co., Ltd. The micro rubber hardness tester MD-1 is capable of measuring the hardness of thin and small samples, which are difficult to measure with a conventional hardness tester, and is approximately 1 / of the spring type rubber hardness tester (durometer) A type. Since it is designed and manufactured as a reduced model of 5, the measured value can be considered to be the same as the measured value in the spring type rubber hardness tester A type. In addition, since the thickness of a normal polishing pad or a hard layer is too thin at 5 mm or less, a spring type rubber hardness meter cannot be evaluated, but it can be evaluated with the micro rubber hardness meter MD-1.

  The thickness of the cushion layer is not particularly limited, but is preferably 0.1 to 5 mm. Since the cushioning property of the polishing pad obtained is less than 0.1 mm, the in-plane uniformity at the time of polishing tends to deteriorate, and a cushion layer exceeding 5 mm is unnecessary due to the necessary characteristics of the polishing pad. More preferably, it is 0.5-3 mm.

In the present invention, a method for producing a cushion layer made of an elastomer in which a peelable resin film is laminated and integrated is obtained by melt-extruding the above-described elastomer material on a resin film, and then rolling the sheet from a roll press or a flat plate press. The method of shaping | molding is mentioned.

  The polishing layer in the present invention is not particularly limited. Specific examples of the material include polyethylene, polypropylene, polyester, polyurethane, polyurea, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polymethyl methacrylate, polycarbonate, polyamide, polyacetal, polyimide, epoxy resin, unsaturated polyester resin, melamine resin, Various laminates such as phenol resin, ABS resin, bakelite, epoxy resin / paper, epoxy resin / fiber, FRP, natural rubber, neoprene (registered trademark) rubber, chloroprene rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, ethylene Various rubbers such as propylene rubber, silicone rubber, and fluorine rubber can be used.

  The structure of the polishing layer of the present invention may be either foamed or non-foamed, but is preferably a foamed structure in terms of good polishing characteristics such as polishing speed and in-plane uniformity, and few defects such as dust and scratches. .

  A known method can be used as a method for forming the foam structure on the polishing layer. For example, various foaming agents are blended in the monomer or polymer, followed by foaming by heating or the like, hollow microbeads are dispersed and cured in the monomer or polymer, and the microbead portion is closed cell A method in which a molten polymer is mechanically stirred and foamed, and then cooled and cured, and a solution in which the polymer is dissolved in a solvent is formed into a sheet, and then in a poor solvent for the polymer. Examples include a method of immersing and extracting only a solvent, a method of impregnating a monomer into a sheet-like polymer having a foamed structure, and then curing by polymerization. Among these, the formation of the foam structure of the polishing layer and the control of the bubble diameter are relatively simple, and the monomer is impregnated into the sheet-like polymer having the foam structure in that the preparation of the polishing layer is also simple. Thereafter, a polymerization and curing method is preferred.

  The material of the sheet-like polymer having a foam structure is not particularly limited as long as it can be impregnated with a monomer. Specifically, polyurethane, polyurea, soft vinyl chloride, natural rubber, neoprene rubber, chloroprene rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, ethylene propylene rubber, silicone rubber, fluoro rubber, etc. Resin sheet, cloth, nonwoven fabric, paper and the like. In addition, these sheet-like polymers may contain various additives such as abrasives, lubricants, antistatic agents, antioxidants, stabilizers and the like for the purpose of improving the characteristics of the polishing pads to be produced. good. Among these, a material mainly composed of polyurethane is preferable in that the bubble diameter can be controlled relatively easily.

  The monomer is not particularly limited as long as it undergoes a polymerization reaction such as addition polymerization, polycondensation, polyaddition, addition condensation, and ring-opening polymerization. Specific examples include vinyl compounds, epoxy compounds, isocyanate compounds, dicarboxylic acids and the like. Among these, a vinyl compound is preferable because it is easy to impregnate and polymerize a sheet-like polymer. The vinyl compound in the present invention is not particularly limited, but a vinyl compound is preferable from the viewpoint of easy impregnation and polymerization in polyurethane. Specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isodecyl 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, maleic acid, maleic Dimethyl acid, diethyl maleate, dipropyl maleate, phenylmaleimide, Hexyl maleimide, isopropyl maleimide, acrylonitrile, acrylamide, vinyl chloride, vinylidene chloride, styrene, alpha-methyl styrene, divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, and the like. These monomers can be used alone or in combination of two or more.

  Among the vinyl compounds mentioned above, methyl methacrylate has good impregnation into polyurethane, is easy to polymerize and cure, polymer polymerized from polymer-cured polyurethane and vinyl compound has high hardness and flatness during polishing It is preferable in terms of good crystallization characteristics.

  The average cell diameter of the polishing layer is not particularly limited, but is preferably 20 to 300 μm. If it is less than 20 μm, the polishing rate during polishing tends to be reduced, or scratches and dust tend to be generated on the surface of the semiconductor substrate after polishing. If it exceeds 300 μm, the rigidity of the polishing layer decreases, resulting in flattening characteristics. This is not preferable because the polishing characteristics such as the above deteriorate or the life of the polishing pad using the polishing layer tends to be shortened. The average cell diameter is more preferably 30 to 250 μm. The average bubble diameter refers to a value measured by observing the cross section of the polishing layer with a SEM at a magnification of 200 times, then measuring the bubble diameter of the recorded SEM photograph with an image processing apparatus, and taking the average value.

The density of the polishing layer is not particularly limited, but is preferably 0.5 to 1.0 g / cm ³ . If it is lower than 0.5 g / cm ^3, the flattening characteristics at the time of polishing will tend to deteriorate, and if it is higher than 1.0 g / cm ³ , the in-plane uniformity at the time of polishing will be deteriorated or polished. Since there is a tendency that scratches and dust are likely to be generated on the surface of the subsequent semiconductor substrate, it is not so preferable. More preferably, it is 0.6 to 0.9 g / cm ³ . The density means a value measured by the method described in Japanese Industrial Standard (JIS) K7222.

  The surface of the polishing layer in the present invention is preferably subjected to processing such as grooves and holes for the purpose of improving the retention and fluidity of the polishing slurry and improving the removal efficiency of polishing debris from the polishing layer surface. The method for forming grooves and holes on the surface of the polishing layer is not particularly limited. Specifically, the method of forming grooves by cutting the surface of the polishing layer using a device such as a router, the heated layer surface is contacted with a heated mold, heat rays, etc., and the contact portion is dissolved. The method of forming a groove | channel by the method, The method of forming the grinding | polishing layer which formed the groove | channel from the beginning using the metal mold | die etc. in which the groove | channel was formed, the method of forming a hole with a drill, a Thomson blade, etc. are mentioned. Further, the shape and diameter of the groove and hole are not particularly limited. Specific examples include a grid shape, a dimple shape, a spiral shape, and a concentric shape.

  The adhesive in the present invention is not particularly limited. Specific examples include various adhesives such as urethane, epoxy, acrylic, and rubber, and various double-sided tapes that are manufactured by applying these adhesives to both surfaces of a substrate such as a film or nonwoven fabric.

    Among various adhesives, as a specific product name of urethane-based adhesives, “Rubilon (registered trademark) 602”, “Rubilon (registered trademark) 603”, “Rubicoat (registered trademark)” manufactured by Toyo Polymer Co., Ltd. are registered as one-pack type. Trademark) F-7 "," Rubilac (Registered Trademark) 603 "," Rubilac (Registered Trademark) 645E "," Rubilon (Registered Trademark) 101 "," Rubilon Ace (Registered Trademark) "," Rubilon (Registered Trademark) 202 " "Rubilon (registered trademark) AAA", "Rubilon (registered trademark) R", "Rubilon (registered trademark) 101SP", "Rubilon (registered trademark) Floor 503", "Lubilon (registered trademark) 302", "Lubilon ( (Registered trademark) 155 ”, manufactured by Toagosei Co., Ltd.“ PU-3030D ”,“ PU-7000D ”, manufactured by Cemedine Co., Ltd.“ UM700 ”,“ UM700S ”, “UM750”, “UM100”, “UM300HK”, “UM550”, “UM600”, “UM600V”, “UM600VL”, “Takelac (registered trademark) A367H”, “Takelac (registered trademark) A369” manufactured by Mitsui Chemicals Polyurethanes, Inc. "Takenate (registered trademark) A7", "Takenate (registered trademark) A19" and the like, and in the two-pack type, "Rubilon (registered trademark) KA-28, KB-28" manufactured by Toyo Polymer Co., Ltd., “RUBILON (registered trademark) KA-38, KB48”, “RUBILON (registered trademark) KA-42, KB-33”, “RUBILON (registered trademark) KA-10, KB-33ME”, “NA-21, NB-” 29 ”, manufactured by Toagosei Co., Ltd.“ PU-62 A agent, PU-62 B agent ”,“ PU-9000, PU-171 ”, etc. But it is not limited to.

    Specific product names of epoxy adhesives include "Aronmighty (registered trademark) AP-0786", "Alonmighty (registered trademark) AP-3510", and "Aronmighty (registered)" manufactured by Toagosei Co., Ltd. Trademark) AP-3513 ", Cemedine Co., Ltd." EP-138 "," EP-170 "," EP-160NL "Two-pack type" Aronmighty (registered trademark) AP-205 "manufactured by Toagosei Co., Ltd. "," Aronmighty (registered trademark) AP-209 "," Aronmighty (registered trademark) AP-317 "," EP-001 "," EP-007 "," EP-330 ", manufactured by Cemedine Co., Ltd., solution Examples of the dilution type include “Aronmighty (registered trademark) AS-60” and “Aronmighty (registered trademark) AS-310” manufactured by Toagosei Co., Ltd., but are not limited thereto. .

    Specific names of acrylic adhesives include “Aronmite (registered trademark) X-2100T” manufactured by Toagosei Co., Ltd., “Y-610”, “Y-620” manufactured by Cemedine Co., Ltd., and the like. However, it is not limited to these.

    Examples of the rubber-based adhesive include “521” and “575” manufactured by Cemedine Co., Ltd. and “Hybon (registered trademark) 1420” manufactured by Hitachi Chemical Co., Ltd., but are not limited thereto.

    In addition to the above-described ordinary adhesives, solvent-free heat-melt adhesives are also preferably used as the adhesive from the viewpoint of environment and workability. Depending on the type of heat-melt adhesive, the adhesive is melted at a temperature of about 70 to 130 ° C., applied to one or both of the adherends with a roll coater, etc., and bonded and pressed while sticky. After the treatment or the like, the adhesive is bonded by cooling and solidifying. In some cases, after bonding, the resin is cured by crosslinking reaction in the air or by moisture or moisture of the adherend, thereby increasing the adhesive strength. Specific examples of heat-melt-type adhesives include polyester-based, modified olefin-based, urethane-based adhesives, etc., as described above, types that are cooled and cured after melt bonding, and after melt-bonding / cooling-curing, and further in the air There are two types that crosslink by reacting with moisture.

    Specific product names of polyester-based heat-melt adhesives include “Aronmelt (registered trademark) PES series” manufactured by Toagosei Co., Ltd., and specific product names of modified olefin-based heat-melt adhesives include Toagosei ( Specific product names of “Aronmelt (registered trademark) PPET series” manufactured by Co., Ltd. and urethane-based heat-melt adhesives are “Aronmelt (registered trademark) R series” manufactured by Toagosei Co., Ltd., and “QR4663” manufactured by Henkel. , “QR4635”, “ARX-1288C2”, “ARX-1288H”, “ARX-1311D”, “ARX-1270”, “ARX1255C1”, “ARX-1308A”, manufactured by Nitta Gelatin Co., Ltd., Hitachi Chemical ( "Hibon (registered trademark) 4812", "Hibon (registered trademark) 4820", "Hibon (registered trademark)" 830 "," Hibon (registered trademark) 4832 "," Hibon (registered trademark) YR713-1W "," Hibon (registered trademark) 4820 "," Hibon (registered trademark) YR346-1 ", manufactured by Mitsui Chemicals Polyurethanes, Inc. “MA-1102W”, “MA-1102S”, “MA-3002T”, “MA-3229”, “MA-1001”, “MA-0110S”, “MA-4008”, “MA-4013”, “MA -4100 "," MA-4014 "," MA-4015 "," MA-5002 "," MA-5203 "," MA-5214 "," MA-5215 "," MA-5310 ", Konishi Co., Ltd. Examples thereof include “KUM3150”, “KUM3150S”, “KUM3200” and the like, but are not limited thereto.

Specific product names of the double-sided adhesive tape include “442JS” manufactured by Sumitomo 3M Co., Ltd., “535A” manufactured by Nitto Denko Corporation, “5782W” manufactured by Sekisui Chemical Co., Ltd., “5604TDM”, Teraoka Co., Ltd. “751”, “758”, “777”, “782”, “761”, “7021”, and the like manufactured by Seisakusho are listed, but not limited thereto.

Adhesives in the present invention, specifically, various adhesives such as urethane, epoxy, acrylic and rubber, and various double-sided tapes produced by applying these adhesives to both surfaces of a substrate such as a film or nonwoven fabric The method of pressure bonding such as is not particularly limited. Specifically, after the adhesive layer described above is formed between the polishing layer and the cushion layer by a method such as laminating a pressure-sensitive adhesive tape to the polishing layer, and applying an adhesive to the polishing layer with various coaters, a flat plate press, The method of pressurizing with a roll press etc. is mentioned. In this case, it is also preferable to heat the press itself within a range that does not adversely affect the polishing layer and the cushion layer. Among these, pressurization by a roll press is preferable from the viewpoint of productivity.

  The applied pressure is not particularly limited, but the linear pressure is preferably 0.5 to 15 kg / cm. When the linear pressure is less than 0.5 kg / cm, there is a tendency that minute air remains at the interface between the polishing layer and the cushion layer and the adhesive (air engagement), and the adhesive force between the polishing layer and the cushion layer decreases. Yes, if it exceeds 15 kg / cm, there is a tendency that the resin film laminated and integrated with the cushion layer peels off and the cushion layer's deformation suppressing effect becomes poor, and the dustproof effect of the cushion layer is lowered. This is not preferable because it deviates from warping of a polishing pad, prevention of air biting, and enhancement of adhesion between the polishing layer and the cushion layer. More preferably, it is 1-10 kg / cm.

  The adhesive force between the polishing layer and the cushion layer in the present invention is not particularly limited, but is preferably higher from the viewpoint of stability of polishing characteristics. Specifically, when a double-sided pressure-sensitive adhesive tape is used for bonding the polishing layer and the cushion layer, the 180 ° peeling force between the polishing layer and the double-sided pressure-sensitive adhesive tape and the cushion layer and the double-sided pressure-sensitive adhesive tape are 900 gf, respectively. / 25 mm or more, and when an adhesive is used for bonding the polishing layer and the cushion layer, the T peel force between the polishing layer and the cushion layer is preferably 2000 gf / 25 mm or more. The 180 ° peel force is a value measured by the method described in JIS K6854-2, and the T peel force is a value measured by the method described in JIS K6854-3.

  Even if the polishing layer and the cushion layer in the present invention are in the form of a single sheet or a roll in which the sheet is continuously wound, there is no particular problem. However, since the cushion layer is made of an elastomer in which a resin film that can be peeled on one side is laminated and integrated, the cushion layer has an effect of suppressing elongation and deformation, so that a roll-shaped one can be used. This is preferable in terms of production efficiency. In particular, when a roll press is used for pressure bonding with the polishing layer, it is very preferable in terms of production efficiency to use a roll-shaped cushion layer.

    In the present invention, the resin film is peeled off from the cushion layer after the polishing layer is pressure-bonded via an adhesive. The peeling method is not particularly limited. The cushion layer after the resin film is peeled is preferably subjected to a treatment such as application of an adhesive tape or application of an adhesive for application to the polishing apparatus surface plate. In this case, it is preferable that the resin film is peeled and removed from the cushion layer immediately before the treatment because dust, dirt, and dirt can be prevented from adhering to the cushion layer.

  The polishing object of the polishing pad manufactured in the present invention is not particularly limited. Specific examples include semiconductor substrates, optical glass, optical lenses, magnetic heads, hard disks, color filters for liquid crystal displays, optical members such as a back plate for plasma displays, ceramics, sapphire, and the like. Among these, application to a semiconductor substrate is particularly preferable. Furthermore, it is provided on a semiconductor wafer that requires very precise polishing characteristics from the effect of the present invention that can produce a polishing pad that is free of warpage and air biting and has sufficient adhesion between the polishing layer and the cushion layer. Further, the surface of the wiring made of an insulating layer, metal and / or metal compound is preferable as an object to be polished. Specifically, the insulating layer includes an interlayer insulating film or lower insulating film of metal wiring, shallow trench isolation (STI) used for element isolation, and the metal wiring includes aluminum, tungsten, copper, and the like. Structurally, there are damascene, dual damascene, plug, etc. Currently, silicon dioxide is mainly used as the insulating film, but due to the problem of delay time, the use of a low dielectric constant insulating film is being studied, and any of them can be polished in the polishing method of the present invention. In addition, when copper is used for the metal wiring, a barrier metal such as silicon nitride is also subject to polishing. Among these, it can apply preferably, when a to-be-polished object is the metal and / or metal compound which were provided on the semiconductor substrate.

  INDUSTRIAL APPLICABILITY According to the present invention, in a method of manufacturing a polishing pad that can be used in a process of flattening a semiconductor substrate, a surface of an insulating layer formed on the semiconductor substrate, or a surface of a metal wiring, warping of the polishing pad and air biting obtained. Thus, it is possible to provide a production method in which sufficient adhesion between the polishing layer and the cushion layer can be obtained, and further, a dustproof effect during production can be obtained.

  Hereinafter, the details of the present invention will be described with reference to examples. Various evaluations of the polishing pad were performed as follows.

  The micro rubber A hardness of the polishing layer and the cushion layer was measured with a micro rubber A hardness meter “MD-1” (manufactured by Kobunshi Keiki Co., Ltd.).

  The density of the polishing layer was measured by the method described in JIS K7222.

  The average bubble diameter of the polishing layer was determined by analyzing a photograph obtained by observing the pad cross section at a magnification of 200 times with an image processing apparatus using a scanning electron microscope “SEM2400” (manufactured by Hitachi, Ltd.). All the bubble diameters present were measured, and the average value was taken as the average bubble diameter.

  The 90 ° peeling force between the cushion layer and the resin film was measured by the method described in JIS K6854-1.

  The thickness of the adhesive after solidification was measured using a scanning electron microscope, “SEM2400” (manufactured by Hitachi, Ltd.), a cross section of the polishing pad cut with a sharp blade like a razor, and the adhesive layer portion at a magnification of 30. It observed in the range of -400 times, and measured with the gauge displayed in an image.

  Polishing evaluation was performed as follows.

  The prepared polishing pad is attached to a polishing machine ("MIRRA (registered trademark)" manufactured by Applied Materials), and a wafer with an oxide film is added while flowing a slurry "SS-25" (manufactured by Cabot) at a rate of 150 mm / min. 100 were continuously polished. The result of polishing the 50th sheet was used as an evaluation result of polishing characteristics. The polishing rate and in-plane uniformity of the wafer after polishing were determined as follows.

  198 points determined using “Lambda Ace (registered trademark)” VM-2000 (Dainippon Screen Mfg. Co., Ltd.) were measured, and the polishing rate at each point was calculated by the following equation (1). Moreover, the in-plane uniformity was calculated by the following equation (2).

  Polishing rate = (thickness of oxide film before polishing−thickness of oxide film after polishing) / polishing time (1).

  In-plane uniformity (%) = (maximum polishing rate−minimum polishing rate) / (maximum polishing rate + minimum polishing rate) × 100 (2).

Example 1
Polyether polyol maintained at a liquid temperature of 40 ° C .: “Sanix (registered trademark) FA-909” (manufactured by Sanyo Chemical Industries, Ltd.) 100 parts by weight, chain extender: 8 parts by weight of ethylene glycol, amine catalyst: 1 part by weight of “Dabco (registered trademark) 33LV” (produced by Air Products Japan), amine catalyst: 0.1 part by weight of “Toyocat (registered trademark) ET” (produced by Tosoh Corporation), silicone foam stabilizer: "TEGOSTAB (registered trademark) B8462" (manufactured by Th. Goldschmidt AG) 0.5 part by weight, foaming agent: A liquid obtained by mixing 0.2 part by weight of water, and isocyanate maintaining the liquid temperature at 40 ° C: "Sunform (registered trademark) NC-703" 95 parts by weight of B liquid was collided with a RIM molding machine at a discharge pressure of 15 MPa, and then kept at 60 ° C. Discharging a discharge rate 500 g / sec within, by standing for 10 minutes, size 700 × 700 mm, foamed polyurethane block thickness 10 mm (micro rubber A hardness: 47 degrees, a density: 0.77 g / cm ^3, average cell Diameter: 37 μm). Thereafter, the foamed polyurethane block was sliced with a slicer to a thickness of 3 mm.

Next, the foamed polyurethane sheet was immersed in methyl methacrylate to which 0.1 part by weight of azobisisobutyronitrile was added for 45 minutes. Next, the foamed polyurethane sheet impregnated with methyl methacrylate was sandwiched between two glass plates via a vinyl chloride gasket, and polymerized and cured by heating at 60 ° C. for 10 hours and at 120 ° C. for 3 hours. After releasing from between the glass plates, vacuum drying was performed at 50 ° C. A polishing layer was prepared by grinding both surfaces of the hard foam sheet thus obtained to a thickness of 2 mm. The obtained polishing layer had a micro rubber A hardness of 92 degrees, a density of 0.77 g / cm ³ , an average cell diameter of 45 μm, and a polymethyl methacrylate content of 55 wt% in the polishing layer. The polishing layer was cut into a circle having a diameter of 508 mm, and a lattice-shaped groove with a width of 1 mm, a depth of 0.8 mm, and a pitch width of 25 mm was formed on the surface.

  Next, a double-sided pressure-sensitive adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) was bonded to the polishing layer at a linear pressure of 2 kg / cm using a laminator, and then the release paper was peeled off. The polyethylene terephthalate film (100 μm thick) Line pressure using a laminator on a cushion layer made of 2 mm thick thermoplastic urethane rubber sheet (micro rubber A hardness: 69 degrees, 90 ° peeling force: 550 gf / 25 mm) melt-extruded on both sides matte finish) Bonding was performed at 2 kg / cm. Thereafter, the polyethylene terephthalate film was peeled off from the opposite surface of the cushion layer. The laminated body of the polishing layer and the cushion layer after bonding did not warp. Further, no air biting was observed on the bonded surface. Further, a double-sided polishing pad was prepared by laminating a double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) under a cushion layer at a linear pressure of 2 kg / cm using a laminator. The polishing pad did not warp. Thereafter, polishing evaluation was performed at a polishing pressure of 4 psi. The polishing rate was 2250 angstroms / minute. The in-plane uniformity was 10.2%.

Example 2
A double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) was bonded to the polishing layer produced in the same manner as in Example 1 at a linear pressure of 2 kg / cm using a laminator, and then the release paper was peeled off to obtain a thickness. A 1 mm thick thermoplastic urethane rubber sheet (micro rubber A hardness: melt-extruded on a polypropylene surface of a 115 μm dry laminate film of polypropylene and polyethylene terephthalate (polypropylene thickness 40 μm, polyethylene terephthalate thickness 75 μm, double-sided matte finish). A laminator was used on a cushion layer composed of 67 °, 90 ° peeling force (190 gf / 25 mm) and bonded at a linear pressure of 2 kg / cm. Thereafter, the dry laminate film of polypropylene and polyethylene terephthalate was peeled off from the opposite surface of the cushion layer. The laminated body of the polishing layer and the cushion layer after bonding did not warp. Further, no air biting was observed on the bonded surface. Further, a double-sided polishing pad was prepared by laminating a double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) under a cushion layer at a linear pressure of 2 kg / cm using a laminator. The polishing pad did not warp. Thereafter, polishing evaluation was performed at a polishing pressure of 4 psi. The polishing rate was 2200 angstroms / minute. The in-plane uniformity was 10.4%.

Comparative Example 1
A double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) was bonded to the polishing layer produced in the same manner as in Example 1 at a linear pressure of 2 kg / cm using a laminator, and then the release paper was peeled off to obtain a thickness. Polyethylene terephthalate from a cushion layer made of a 2 mm thick thermoplastic urethane rubber sheet (micro rubber A hardness: 69 degrees, 90 ° peeling force: 550 gf / 25 mm) melt-extruded on a 100 μm polyethylene terephthalate film (double-sided matte finish) After peeling off and removing the film, a laminator was used on the surface opposite to the surface from which the polyethylene terephthalate film had been removed, and the film was bonded at a linear pressure of 2 kg / cm. Warpage was observed in the laminate of the polishing layer and the cushion layer after bonding. Further, no air biting was observed on the bonded surface.

  Further, a double-sided polishing pad was prepared by laminating a double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) under a cushion layer at a linear pressure of 2 kg / cm using a laminator. Adhesion of dust was observed on the cushion layer before bonding, and a removal operation was necessary. Further, the polishing pad after bonding was warped. Thereafter, polishing evaluation was performed at a polishing pressure of 4 psi. The polishing rate was 2300 angstroms / minute. The in-plane uniformity was 18.9%.

Comparative Example 2
A double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) was bonded to the polishing layer produced in the same manner as in Example 1 at a linear pressure of 2 kg / cm using a laminator, and then the release paper was peeled off to obtain a thickness. Polyethylene terephthalate from a cushion layer made of a 2 mm thick thermoplastic urethane rubber sheet (micro rubber A hardness: 69 degrees, 90 ° peeling force: 550 gf / 25 mm) melt-extruded on a 100 μm polyethylene terephthalate film (double-sided matte finish) After the film was peeled and removed, a laminator was used on the surface opposite to the surface from which the polyethylene terephthalate film had been removed, and the film was bonded at a linear pressure of 0.3 kg / cm. No warpage was observed in the laminate of the polishing layer and the cushion layer after bonding. Moreover, many minute air bites were seen on the bonding surface.

  Further, a double-sided polishing pad was prepared by laminating a double-sided adhesive tape “442JS” (manufactured by Sumitomo 3M Co., Ltd.) under a cushion layer at a linear pressure of 2 kg / cm using a laminator. Adhesion of dust was observed on the cushion layer before bonding, and a removal operation was necessary. Further, no warping was observed on the polishing pad after bonding. Moreover, many minute air bites were seen on the bonding surface. Thereafter, polishing evaluation was performed at a polishing pressure of 4 psi. The polishing rate was 2300 angstroms / minute. In-plane uniformity was 17.3%.

Claims (5)

In the manufacturing method of the polishing pad that adheres the polishing layer to the cushion layer via an adhesive, the cushion layer is made of elastomer, and the resin film that can be peeled off on one side by melting and extruding the elastomer material on the resin film is laminated and integrated A method for producing a polishing pad, comprising: a step of peeling and removing a resin film from a cushion layer after a step of pressure-bonding the polishing layer with an adhesive on the opposite surface of the cushion layer. The method for producing a polishing pad according to claim 1, wherein the elastomer is non-foamed. The manufacturing method of the polishing pad of Claim 1 or 2 which performs pressurization adhesion by roll press pressurization. The method for producing a polishing pad according to any one of claims 1 to 3, wherein the 90 ° peeling force between the cushion layer and the resin film is 50 to 1000 gf / 25 mm. The method for producing a polishing pad according to any one of claims 1 to 4, wherein the cushion layer has a thickness of 0.1 to 5 mm.