JP2013082035A - Laminated polishing pad and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a laminated polishing pad allowing a light transmitting region to be easily stuck and not causing deformation of the pad.SOLUTION: A method of manufacturing a laminated polishing pad includes: a step of preparing a polishing layer by temporarily fixing a light transmitting region in an opening A of a polishing region; a step of providing a bonding member including a hot-melt adhesive which is heated and melted between the polishing layer and a support layer; and a step of laminating the polishing layer and the support layer by curing the hot-melt adhesive.

Description

  The present invention relates to a laminated polishing pad used when planarizing unevenness on a surface of an object to be polished such as a semiconductor wafer by chemical mechanical polishing (CMP) and a manufacturing method thereof. The present invention relates to a laminated polishing pad having a window (light transmission region) for detection and a manufacturing method thereof.

  When manufacturing a semiconductor device, a conductive film is formed on the surface of a semiconductor wafer (hereinafter also referred to as a wafer), and a wiring layer is formed by photolithography, etching, or the like. A process for forming an interlayer insulating film is performed on the surface of the wafer, and these processes cause irregularities made of a conductor such as metal or an insulator on the wafer surface. In recent years, miniaturization of wiring and multilayer wiring have been advanced for the purpose of increasing the density of semiconductor integrated circuits, and along with this, technology for flattening the irregularities on the wafer surface has become important.

  As a method for flattening the irregularities on the wafer surface, a CMP method is generally employed. CMP is a technique of polishing using a slurry-like abrasive (hereinafter referred to as slurry) in which abrasive grains are dispersed in a state where the surface to be polished of a wafer is pressed against the polishing surface of a polishing pad.

  As shown in FIG. 1, for example, a polishing apparatus generally used in CMP includes a polishing surface plate 2 that supports a polishing pad 1 and a support base (polishing head) 5 that supports a material to be polished (wafer or the like) 4. And a backing material for uniformly pressing the wafer and a supply mechanism for the abrasive 3. The polishing pad 1 is attached to the polishing surface plate 2 by attaching it with a double-sided tape, for example. The polishing surface plate 2 and the support base 5 are disposed so that the polishing pad 1 and the material to be polished 4 supported by each of the polishing surface plate 2 and the support base 5 are opposed to each other, and are provided with rotating shafts 6 and 7 respectively. Further, a pressurizing mechanism for pressing the workpiece 4 against the polishing pad 1 is provided on the support base 5 side.

  In performing such CMP, there is a problem in determining the wafer surface flatness. In other words, it is necessary to detect when the desired surface characteristics or planar state is reached. Conventionally, with regard to the thickness of the oxide film, the polishing rate, and the like, a test wafer is periodically processed, and after confirming the result, a product wafer is polished.

  However, in this method, the time and cost for processing the test wafer are wasted, and the polishing result differs between the test wafer and the product wafer that have not been processed in advance due to the loading effect peculiar to CMP. If it is not actually processed, it is difficult to accurately predict the processing result.

  Therefore, recently, in order to solve the above-mentioned problems, there is a demand for a method capable of detecting a point in time when desired surface characteristics and thickness are obtained in the CMP process. Various methods are used for such detection, but optical detection means are becoming mainstream in terms of measurement accuracy and spatial resolution in non-contact measurement.

  Specifically, the optical detection means is a method of detecting an end point of polishing by irradiating a wafer with a light beam through a window (light transmission region) through a polishing pad and monitoring an interference signal generated by the reflection. It is.

  Various methods for detecting the end point of polishing using such optical means and polishing pads used in the method have been proposed.

  In addition, as a polishing pad used for high-precision polishing, a polyurethane resin foam sheet is generally used. However, although the polyurethane resin foam sheet is excellent in local flattening ability, it is difficult to apply a uniform pressure to the entire wafer surface because of insufficient cushioning properties. For this reason, usually, a soft cushion layer is separately provided on the back surface of the polyurethane resin foam sheet, and is used for polishing as a laminated polishing pad.

  However, conventional laminated polishing pads generally have a polishing layer and a cushion layer bonded to each other with a double-sided tape, but the slurry enters between the polishing layer and the cushion layer during polishing, reducing the durability of the double-sided tape. However, there is a problem that the polishing layer and the cushion layer are easily peeled off.

  As a method for solving the above problem, for example, the following techniques have been proposed.

  Patent Document 1 discloses that a plastic film and a polishing pad are bonded using a reactive hot melt adhesive.

  Patent Document 2 discloses a polishing pad in which a base layer and a polishing layer are bonded by a hot melt adhesive layer.

  Patent Document 3 discloses a polishing pad in which a polishing layer and a base layer are bonded by a double-sided tape, and is composed of a hot-melt adhesive between the back surface of the polishing layer and the double-sided tape, and blocks polishing slurry. A technique for providing a water blocking layer is disclosed.

  Patent Document 4 discloses a polishing pad in which a polishing layer and a lower layer are bonded with a hot melt adhesive containing EVA.

  In Patent Document 5, a step of laminating a cushion layer on a polishing layer having a polishing region and an opening A, a part of the cushion layer in the opening A is removed, and an opening smaller than the opening A is formed in the cushion layer. Forming a portion B, providing a hot melt adhesive on the cushion layer around the opening B, installing a light transmission region in the opening A and on the hot melt adhesive, and laser light. Irradiating from above the light transmitting region to melt the hot melt adhesive, and curing the melted hot melt adhesive to bond the light transmitting region to the cushion layer via the hot melt adhesive. A method of manufacturing a polishing pad is disclosed.

  In the manufacturing method of the polishing pad described in Patent Document 5, the light transmission region is bonded to the cushion layer by irradiating laser light from above the light transmission region to melt and cure the hot melt adhesive. There is a problem that the manufacturing method is complicated due to the use of Further, when the hot melt adhesive is melted and cured by heating instead of laser light, there is a problem that the previously laminated polishing layer and cushion layer are easily deformed by heat.

JP 2002-224944 A JP-A-2005-167200 JP 2009-95945 A JP 2010-525956 A JP 2009-45694 A

  An object of the present invention is to provide a method for manufacturing a laminated polishing pad in which a light transmission region can be easily attached and the pad is not deformed.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by a method for producing a laminated polishing pad described below, and have completed the present invention.

  That is, the present invention provides a process for preparing a polishing layer by temporarily fixing a light transmission region in the opening A of the polishing region, and an adhesive member containing a hot-melt adhesive that is heated and melted between the polishing layer and the support layer. The present invention relates to a method for producing a laminated polishing pad, comprising a step of providing between and a step of curing the hot melt adhesive to bond the polishing layer and a support layer.

  By preliminarily fixing the light transmission region in the opening A of the polishing region, the polishing layer and the support layer are bonded to the adhesive member, and at the same time, the temporarily fixed light transmission region is bonded to the adhesive member. Can do.

  The temporary fixing is preferably performed by fitting a light transmission region having the same shape as the opening A into the opening A that is narrowed from the polishing surface side toward the polishing back surface side.

  The temporary fixing may be performed by fitting a light transmission region in the opening A and bonding the surface of the polishing region and the surface of the light transmission region with a removable adhesive tape.

  The adhesive member is an adhesive layer containing a polyester-based hot melt adhesive, or a double-sided tape having the adhesive layer on both sides of a substrate, and the polyester-based hot melt adhesive is a polyester resin 100 that is a base polymer. It is preferable to contain 2 to 10 parts by weight of an epoxy resin having two or more glycidyl groups in one molecule with respect to parts by weight.

  2 to 10 parts by weight of an epoxy resin having two or more glycidyl groups in one molecule is added to 100 parts by weight of a polyester resin as a base polymer to a polyester hot melt adhesive that is an adhesive layer forming material. By cross-linking the polyester resin, the durability of the adhesive member against “slipping” that occurs during polishing is improved even when the temperature is high due to long-time polishing, and peeling occurs between the polishing layer and the support layer. A laminated polishing pad that is difficult to perform is obtained.

  When the addition amount of the epoxy resin is less than 2 parts by weight, the durability of the adhesive member against “slipping” generated during polishing becomes insufficient when the temperature becomes high due to long-time polishing. It becomes easy to peel between layers. On the other hand, when it exceeds 10 parts by weight, the hardness of the adhesive layer becomes too high and the adhesiveness is lowered, so that it is easy to peel between the polishing layer and the support layer.

  The polyester resin as the base polymer is preferably a crystalline polyester resin. By using the crystalline polyester resin, the chemical resistance to the slurry is improved, and the adhesive force of the adhesive layer is hardly lowered.

  The present invention also relates to a laminated polishing pad obtained by the production method, and a method for producing a semiconductor device including a step of polishing a surface of a semiconductor wafer using the laminated polishing pad.

  According to the method for manufacturing a laminated polishing pad of the present invention, the light transmission region can be bonded and fixed to the polishing pad by a simple method. In addition, when the polishing layer and the support layer are bonded to the adhesive member, since the light transmission region is simultaneously bonded to the adhesive member, the laminated polishing pad is not deformed by heat unlike the conventional manufacturing method.

Schematic configuration diagram showing an example of a polishing apparatus used in CMP polishing Schematic sectional view showing a state where a light transmission region is temporarily fixed in the opening A of the polishing region Schematic sectional view showing a state where a light transmission region is temporarily fixed in the opening A of the polishing region Schematic sectional view showing a state where a light transmission region is temporarily fixed in the opening A of the polishing region Schematic sectional view showing an example of the laminated polishing pad of the present invention

  The method for producing a laminated polishing pad according to the present invention includes a step of temporarily fixing a light transmission region in an opening A of a polishing region to produce a polishing layer, and an adhesive member containing a hot melt adhesive heated and melted. And a step of providing between the polishing layer and the support layer, and a step of curing the hot melt adhesive to bond the polishing layer and the support layer together.

  The polishing region may be a foam or a non-foam, but is preferably a foam having fine bubbles. Examples of materials for the polishing region include polyurethane resins, polyester resins, polyamide resins, acrylic resins, polycarbonate resins, halogen resins (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, olefin resins (polyethylene). , Polypropylene, etc.), epoxy resins, photosensitive resins and the like, or a mixture of two or more. Polyurethane resin is particularly preferable as a material for forming a polishing region because it has excellent wear resistance and a polymer having desired physical properties can be easily obtained by variously changing the raw material composition. Hereinafter, a polishing region made of a polyurethane resin foam will be described.

  The polyurethane resin comprises an isocyanate component, a polyol component (high molecular weight polyol, low molecular weight polyol), and a chain extender.

  As the isocyanate component, a known compound in the field of polyurethane can be used without particular limitation. As the isocyanate component, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, Aromatic diisocyanates such as p-phenylene diisocyanate, m-phenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate; ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, etc. Aliphatic diisocyanate; 1,4-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isophorone diisocyanate Isocyanate, alicyclic diisocyanates such as norbornane diisocyanate. These may be used alone or in combination of two or more.

  Examples of the high molecular weight polyol include those usually used in the technical field of polyurethane. Examples include polyether polyols typified by polytetramethylene ether glycol, polyethylene glycol, etc., polyester polyols typified by polybutylene adipate, polycaprolactone polyols, reactants of polyester glycols such as polycaprolactone and alkylene carbonate, etc. Polyester polycarbonate polyol obtained by reacting ethylene carbonate with polyhydric alcohol and then reacting the obtained reaction mixture with organic dicarboxylic acid, polycarbonate polyol obtained by transesterification of polyhydroxyl compound and aryl carbonate Etc. These may be used alone or in combination of two or more.

  In addition to the high molecular weight polyols described above as the polyol component, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, 1,4-bis (2 -Hydroxyethoxy) benzene, trimethylolpropane, glycerin, 1,2,6-hexanetriol, pentaerythritol, tetramethylolcyclohexane, methylglucoside, sorbitol, mannitol, dulcitol, sucrose, 2,2,6,6-tetrakis (Hydroxymethyl) cyclohexanol, diethanolamine, N- methyldiethanolamine, and can be used in combination of low molecular weight polyols such as triethanolamine. Moreover, low molecular weight polyamines, such as ethylenediamine, tolylenediamine, diphenylmethanediamine, and diethylenetriamine, can also be used in combination. Also, alcohol amines such as monoethanolamine, 2- (2-aminoethylamino) ethanol, and monopropanolamine can be used in combination. These low molecular weight polyols and low molecular weight polyamines may be used alone or in combination of two or more. The blending amount of the low molecular weight polyol, the low molecular weight polyamine or the like is not particularly limited, and is appropriately determined depending on the properties required for the polishing pad (polishing layer) to be produced.

  When a polyurethane resin foam is produced by a prepolymer method, a chain extender is used for curing the prepolymer. The chain extender is an organic compound having at least two active hydrogen groups, and examples of the active hydrogen group include a hydroxyl group, a primary or secondary amino group, and a thiol group (SH). Specifically, 4,4′-methylenebis (o-chloroaniline) (MOCA), 2,6-dichloro-p-phenylenediamine, 4,4′-methylenebis (2,3-dichloroaniline), 3,5 -Bis (methylthio) -2,4-toluenediamine, 3,5-bis (methylthio) -2,6-toluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2 , 6-diamine, trimethylene glycol-di-p-aminobenzoate, polytetramethylene oxide-di-p-aminobenzoate, 4,4′-diamino-3,3 ′, 5,5′-tetraethyldiphenylmethane, 4, 4'-diamino-3,3'-diisopropyl-5,5'-dimethyldiphenylmethane, 4,4'-diamino-3,3 ', 5,5'-tetra Sopropyldiphenylmethane, 1,2-bis (2-aminophenylthio) ethane, 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphenylmethane, N, N′-di-sec-butyl -4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, m-xylylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, m-phenylenediamine And polyamines exemplified by p-xylylenediamine and the like, or the low molecular weight polyols and low molecular weight polyamines mentioned above. These may be used alone or in combination of two or more.

  The polyurethane resin foam can be produced by applying a known urethanization technique such as a melting method or a solution method, but is preferably produced by a melting method in consideration of cost, work environment, and the like.

  The polyurethane resin foam can be produced by either the prepolymer method or the one-shot method. However, an isocyanate-terminated prepolymer is synthesized beforehand from an isocyanate component and a polyol component, and this is reacted with a chain extender. The polymer method is preferred because the resulting polyurethane resin has excellent physical properties.

  Examples of the method for producing a polyurethane resin foam include a method of adding hollow beads, a mechanical foaming method, and a chemical foaming method.

  In particular, a mechanical foaming method using a silicone surfactant which is a copolymer of polyalkylsiloxane and polyether and does not have an active hydrogen group is preferable.

  In addition, you may add stabilizers, such as antioxidant, a lubricant, a pigment, a filler, an antistatic agent, and another additive as needed.

  The polyurethane resin foam may be a closed cell type or an open cell type.

  Polyurethane resin foam can be manufactured by batch feeding each component into a container and stirring, or by continuously supplying each component and non-reactive gas to the stirring device and stirring, It may be a continuous production method in which a dispersion is sent out to produce a molded product.

  In addition, the prepolymer that is the raw material of the polyurethane resin foam is placed in a reaction vessel, and then a chain extender is added and stirred, and then poured into a casting mold of a predetermined size to produce a block, and the block is shaped like a bowl or a band saw. In the method of slicing using a slicer, or in the above-described casting step, a thin sheet may be used. Alternatively, a raw material resin may be dissolved and extruded from a T-die to directly obtain a sheet-like polyurethane resin foam.

  The polishing surface that comes into contact with the material to be polished in the polishing region preferably has a concavo-convex structure for holding and renewing the slurry. The polishing area made of foam has many openings on the polishing surface and has the function of holding and updating the slurry. By forming a concavo-convex structure on the polishing surface, the slurry can be held and updated more efficiently. It can be performed well, and destruction of the material to be polished due to adsorption with the material to be polished can be prevented. The concavo-convex structure is not particularly limited as long as it is a shape that holds and renews the slurry. For example, an XY lattice groove, a concentric circular groove, a through hole, a hole that does not penetrate, a polygonal column, a cylinder, a spiral groove, Examples include eccentric circular grooves, radial grooves, and combinations of these grooves. In addition, these uneven structures are generally regular, but in order to make the slurry retention and renewability desirable, the groove pitch, groove width, groove depth, etc. should be changed for each range. Is also possible.

  The shape of the polishing region is not particularly limited, and may be circular or long. The size of the polishing region can be appropriately adjusted according to the polishing apparatus to be used. In the case of a circular shape, the diameter is about 30 to 150 cm, and in the case of a long shape, the length is about 5 to 15 m. The width is about 60 to 250 cm.

  Although the thickness of a grinding | polishing area | region is not specifically limited, Usually, it is about 0.8-4 mm, and it is preferable that it is 1.2-2.5 mm.

  The means for forming the opening A in the polishing region is not particularly limited. For example, a method of pressing or grinding with a cutting tool, a method of using a laser such as a carbonic acid laser, a gold having the shape of the opening A Examples include a method in which a raw material is poured into a mold and cured. The size of the opening A is not particularly limited.

  The planar shape of the opening A is not particularly limited, and examples thereof include a circle, an ellipse, a square, a rectangle, and a polygon. Further, the cross-sectional shape of the opening A is not particularly limited, but in order to make it easy to temporarily fix the light transmission region in the opening A, it is preferably a shape that becomes narrower from the polishing surface side toward the polishing back surface side, Specifically, a trapezoid as shown in FIG.

  The material for forming the light transmission region is not particularly limited, but it is possible to detect the optical end point with high accuracy while polishing and use a material having a light transmittance of 20% or more over the entire wavelength range of 400 to 700 nm. It is preferable that the material has a light transmittance of 50% or more. Examples of such materials include polyurethane resins, polyester resins, phenol resins, urea resins, melamine resins, epoxy resins, and acrylic resins, and other thermosetting resins, polyurethane resins, polyester resins, polyamide resins, cellulose resins, Acrylic resins, polycarbonate resins, halogen resins (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene, olefin resins (polyethylene, polypropylene, etc.), thermoplastic resins, butadiene rubber, isoprene rubber, etc. Examples thereof include rubber, photo-curing resin that is cured by light such as ultraviolet rays and electron beams, and photosensitive resin. These resins may be used alone or in combination of two or more.

  The material used for the light transmission region preferably has the same or greater grindability than the material used for the polishing region. Grindability refers to the degree to which a material to be polished is ground during polishing. In such a case, the light transmission region does not protrude from the polishing region, and scratches on the material to be polished and dechucking errors during polishing can be prevented.

  In addition, it is preferable to use a material similar to the material used for the polishing region and the physical properties of the polishing region. In particular, a highly abrasion-resistant polyurethane resin that can suppress light scattering in the light transmission region due to dressing marks during polishing is desirable.

  The method for producing the light transmission region is not particularly limited, and can be produced by a known method. For example, a polyurethane resin block can be made with a band saw type or canna type slicer to a predetermined thickness, a resin can be poured into a mold with a cavity with a predetermined thickness and cured, and coating or sheet molding techniques can be used. The method that was used is used.

  The size of the light transmission region is not particularly limited, but is preferably the same size as the opening A of the polishing region. The planar shape of the light transmission region is preferably the same shape as the opening A. The cross-sectional shape of the light transmission region is preferably the same as that of the opening A, and in order to make it easier to temporarily fix the light transmission region in the opening A, the cross-sectional shape is narrowed from the polishing surface side to the polishing back surface side. The shape is preferably a trapezoid as shown in FIG.

  The thickness of the light transmission region is not particularly limited, but is preferably equal to or less than the thickness of the polishing region. When the light transmission region is thicker than the polishing region, the material to be polished may be damaged by the protruding portion during polishing. Further, the light transmission region is deformed by the stress applied during polishing, and is greatly distorted optically, so that there is a possibility that the optical end point detection accuracy of polishing is lowered. On the other hand, if the thickness is too thin, the durability may be insufficient, or a large recess may be formed on the upper surface of the light transmission region, and a large amount of slurry may accumulate, resulting in a decrease in optical end point detection accuracy.

  In the method for producing a laminated polishing pad according to the present invention, first, a light transmission region is temporarily fixed in the opening A of the polishing region to produce a polishing layer.

  The method of temporarily fixing is not particularly limited. For example, (1) a light transmission region having the same shape as the opening A is fitted into the opening A that is narrowed from the polishing surface side toward the polishing back surface side. (2) A method in which a light transmission region is fitted in the opening A, and a surface of the polishing region and a surface of the light transmission region are bonded with a removable adhesive tape (see FIG. 3). , (1) and (2) are used together (see FIG. 4). As the removable pressure-sensitive adhesive tape, known ones can be used without particular limitation.

  Thereafter, an adhesive member containing a hot-melt adhesive heated and melted is provided between the polishing layer and the support layer.

  As an adhesive member, the adhesive bond layer containing a hot-melt-adhesive is mentioned, for example.

  The thickness of the adhesive layer is preferably 10 to 200 μm, more preferably 30 to 100 μm.

  Instead of the adhesive layer, a double-sided tape having the adhesive layer on both sides of the substrate may be used. The base material can prevent the slurry from penetrating to the support layer side, and can prevent peeling between the support layer and the adhesive layer.

  Examples of the substrate include polyester films such as polyethylene terephthalate film and polyethylene naphthalate film; polyolefin films such as polyethylene film and polypropylene film; nylon film and the like. Among these, it is preferable to use a polyester film having excellent properties for preventing water permeation.

  The surface of the substrate may be subjected to easy adhesion treatment such as corona treatment or plasma treatment.

  Although the thickness in particular of a base material is not restrict | limited, It is preferable that it is 10-180 micrometers from viewpoints, such as transparency, a softness | flexibility, and rigidity.

  When a double-sided tape is used, the thickness of the adhesive layer is preferably 10 to 200 μm, more preferably 30 to 100 μm.

  A known hot melt adhesive can be used without any particular limitation, but a polyester hot melt adhesive is preferably used.

  The polyester-based hot melt adhesive preferably contains at least a polyester resin as a base polymer and an epoxy resin having two or more glycidyl groups in one molecule as a crosslinking component.

  As the polyester resin, a known resin obtained by condensation polymerization of an acid component and a polyol component can be used, and it is particularly preferable to use a crystalline polyester resin.

  Examples of the acid component include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. These may be used alone or in combination of two or more.

  Specific examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic anhydride, α-naphthalenedicarboxylic acid, β-naphthalenedicarboxylic acid, and ester formers thereof.

  Specific examples of the aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecylenic acid, dodecanedioic acid, and ester formers thereof.

  Specific examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and the like.

  As the acid component, unsaturated acids such as maleic acid, fumaric acid and dimer acid, polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid may be used in combination.

  Examples of the polyol component include dihydric alcohols and polyhydric alcohols such as aliphatic glycols and alicyclic glycols. These may be used alone or in combination of two or more.

  Specific examples of the aliphatic glycol include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Hexanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, 3-methylpentanediol, 2,2,3-trimethylpentanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc. It is done.

  Specific examples of the alicyclic glycol include 1,4-cyclohexanedimethanol and hydrogenated bisphenol A.

  Examples of the polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.

  The crystalline polyester resin can be synthesized by a known method. For example, there are a melt polymerization method in which raw materials and a catalyst are charged and heated at a temperature equal to or higher than the melting point of the product, a solid phase polymerization method in which polymerization is performed at a temperature lower than the melting point of the product, a solution polymerization method using a solvent, It may be adopted.

  The melting point of the crystalline polyester resin is preferably 100 to 200 ° C. When the melting point is less than 100 ° C., the adhesive force of the hot melt adhesive is reduced due to heat generated during polishing, and when it exceeds 200 ° C., the temperature at which the hot melt adhesive is melted increases, The pad is warped and tends to adversely affect the polishing characteristics.

  The number average molecular weight of the crystalline polyester resin is preferably 5,000 to 50,000. When the number average molecular weight is less than 5,000, the mechanical properties of the hot melt adhesive deteriorate, so that sufficient adhesion and durability cannot be obtained. When the number average molecular weight exceeds 50,000, the crystalline polyester resin is synthesized. There is a tendency for production problems such as gelation to occur, and the performance as a hot melt adhesive tends to deteriorate.

  Examples of the epoxy resin include bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, stilbene type epoxy resin, biphenyl type epoxy resin, and bisphenol A novolak type epoxy resin. , Cresol novolac type epoxy resin, diaminodiphenylmethane type epoxy resin, and polyphenyl base epoxy resin such as tetrakis (hydroxyphenyl) ethane base, fluorene-containing epoxy resin, triglycidyl isocyanurate, heteroaromatic ring (for example, triazine ring) Aromatic epoxy resins such as epoxy resins contained; aliphatic glycidyl ether type epoxy resins, aliphatic glycidyl ester type epoxy resins, alicyclic glycidies Ether type epoxy resin, aromatic epoxy resins such as alicyclic glycidyl ester type epoxy resins. These may be used alone or in combination of two or more.

  Among these, it is preferable to use a cresol novolac type epoxy resin from the viewpoint of adhesion to the polishing layer during polishing.

  The epoxy resin is preferably added in an amount of 2 to 10 parts by weight, more preferably 3 to 7 parts by weight, based on 100 parts by weight of the polyester resin as the base polymer.

  The polyester hot melt adhesive may contain known additives such as softeners such as olefin resins, tackifiers, fillers, stabilizers, and coupling agents. Moreover, you may contain well-known inorganic fillers, such as a talc.

  The polyester hot melt adhesive is prepared by mixing at least the polyester resin, the epoxy resin, and the like by an arbitrary method. For example, single-screw extruder, meshing same-direction parallel-shaft twin-screw extruder, mesh-type different-direction parallel-shaft twin-screw extruder, mesh-type different-direction oblique-shaft twin-screw extruder, non-meshing-type twin-screw extrusion Each raw material is mixed by an extruder, a kneader, etc. such as a machine, an incomplete meshing twin screw extruder, a kneader type extruder, a planetary gear type extruder, a transfer mix extruder, a ram extruder, a roller extruder, etc. Prepare.

  The melting point of the polyester hot melt adhesive is preferably 100 to 200 ° C.

  Moreover, it is preferable that the specific gravity of a polyester-type hot-melt-adhesive is 1.1-1.3.

  The melt flow index (MI) of the polyester hot melt adhesive is preferably 16 to 26 g / 10 min under conditions of 150 ° C. and a load of 2.16 kg.

  The polyester hot melt adhesive can be used in any form such as pellet form, powder form, sheet form, film form, solution form dissolved in a solvent, etc. It is preferable to use one.

  The support layer supplements the characteristics of the polishing layer. As the support layer, a layer having a lower elastic modulus than the polishing layer (cushion layer) may be used, or a layer having a higher elastic modulus than the polishing layer (high elastic layer) may be used. The cushion layer is necessary in order to achieve both planarity and uniformity in a trade-off relationship in CMP. Planarity refers to the flatness of a pattern portion when a material having fine irregularities generated during pattern formation is polished, and uniformity refers to the uniformity of the entire material to be polished. The planarity is improved by the characteristics of the polishing layer, and the uniformity is improved by the characteristics of the cushion layer. The high elastic layer is used for improving the planarization characteristics of the laminated polishing pad when a soft polishing layer is used in CMP to suppress the occurrence of scratches. In addition, by using a highly elastic layer, it is possible to suppress excessive cutting of the edge portion of the material to be polished.

  Examples of the cushion layer include fiber nonwoven fabrics such as polyester nonwoven fabric, nylon nonwoven fabric, and acrylic nonwoven fabric; resin-impregnated nonwoven fabrics such as polyester nonwoven fabric impregnated with polyurethane; polymer resin foams such as polyurethane foam and polyethylene foam; butadiene rubber And rubber resins such as isoprene rubber; and photosensitive resins.

  Examples of the highly elastic layer include polyester films such as polyethylene terephthalate films and polyethylene naphthalate films; polyolefin films such as polyethylene films and polypropylene films; nylon films and the like.

  When the support layer is opaque, it is preferable to provide an opening B for transmitting light, as shown in FIG.

  There is no particular limitation on the method of providing the adhesive member containing the hot-melt adhesive that is heated and melted between the polishing layer and the support layer. For example, (1) the adhesive member containing the hot-melt adhesive is used as the support layer (or the polishing layer). ), The hot melt adhesive is heated and melted with a heater, and then the polishing layer (or support layer) is stacked on the molten adhesive layer. (2) On the support layer (or polishing layer) A method of applying a hot-melt adhesive hot melt and then laminating an abrasive layer (or support layer) on the melted hot-melt adhesive, (3) an adhesive member containing the abrasive layer, hot-melt adhesive, and support Examples include a method of laminating layers and heating the obtained laminate to melt the hot melt adhesive. Each member may be laminated and pressed to adhere. From the viewpoint of preventing deformation of the laminated polishing pad due to heat, the method (1) or (2) is preferable.

  Thereafter, the hot melt adhesive is cured and the polishing layer and the support layer are bonded together to produce a laminated polishing pad. Since the light transmission region is temporarily fixed to the polishing layer in advance, the polishing layer and the support layer are bonded together by the adhesive member, and at the same time, the temporarily fixed light transmission region is bonded to the adhesive member and completely fixed. Is done.

  The laminated polishing pad of the present invention may be provided with a double-sided tape on the surface to be bonded to the platen.

  The semiconductor device is manufactured through a step of polishing the surface of the semiconductor wafer using the polishing pad. A semiconductor wafer is generally a laminate of a wiring metal and an oxide film on a silicon wafer. The method and apparatus for polishing the semiconductor wafer are not particularly limited. For example, as shown in FIG. 1, a polishing surface plate 2 that supports the laminated polishing pad 1, a support table (polishing head) 5 that supports the semiconductor wafer 4, and the wafer. This is carried out using a backing material for performing uniform pressurization and a polishing apparatus equipped with a polishing agent 3 supply mechanism. The laminated polishing pad 1 is attached to the polishing surface plate 2 by attaching it with a double-sided tape, for example. The polishing surface plate 2 and the support base 5 are arranged so that the laminated polishing pad 1 and the semiconductor wafer 4 supported on each of the polishing surface plate 2 and the support table 5 face each other, and are provided with rotating shafts 6 and 7 respectively. Further, a pressure mechanism for pressing the semiconductor wafer 4 against the laminated polishing pad 1 is provided on the support base 5 side. In polishing, the semiconductor wafer 4 is pressed against the laminated polishing pad 1 while rotating the polishing surface plate 2 and the support base 5, and polishing is performed while supplying slurry. The flow rate of the slurry, the polishing load, the polishing platen rotation speed, and the wafer rotation speed are not particularly limited and are appropriately adjusted.

  As a result, the protruding portion of the surface of the semiconductor wafer 4 is removed and polished flat. Thereafter, a semiconductor device is manufactured by dicing, bonding, packaging, or the like. The semiconductor device is used for an arithmetic processing device, a memory, and the like.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to these Examples.

[Measurement and evaluation methods]
(Measurement of melting point)
The melting point of the polyester hot melt adhesive was measured using TOLEDO DSC822 (manufactured by METTLER) at a temperature elevation rate of 20 ° C./min.

(Measurement of specific gravity)
This was performed according to JIS Z8807-1976. An adhesive layer made of a polyester-based hot melt adhesive is cut into a 4 cm × 8.5 cm strip (thickness: arbitrary), and a specific gravity measurement sample is used. The temperature is 23 ° C. ± 2 ° C. and the humidity is 50% ± 5%. It was left in the environment for 16 hours. The specific gravity was measured using a hydrometer (manufactured by Sartorius).

(Measurement of melt flow index (MI))
The melt flow index of the polyester hot melt adhesive was measured under conditions of 150 ° C. and 2.16 kg according to ASTM-D-1238.

(Measurement of shear stress)
Three samples of 25 mm × 25 mm were cut from the produced laminated polishing pad, the polishing layer and the support layer of each sample were pulled at a pulling rate of 300 mm / min, and the shear stress (N / 25 mm ² ) at this time was measured. Table 1 shows the average value of three samples. Moreover, the peeling state of the sample at that time was confirmed. Further, after polishing for 60 hours under the following conditions using the produced laminated polishing pad, the shear stress was measured by the same method as described above, and the peeled state was confirmed.

(Evaluation of polishing rate uniformity)
Using SPP600S (manufactured by Okamoto Machine Tool Co., Ltd.) as a polishing apparatus, the uniformity of the polishing rate was evaluated using the produced laminated polishing pad. The polishing rate was calculated from the polishing amount at this time by polishing a wafer obtained by forming a 10,000-mm tungsten film on an 8-inch silicon wafer for 60 seconds. Polishing was performed for 60 hours while changing the wafer. A non-contact resistance measuring system (manufactured by Napson, Model-NC-80M) was used for measuring the film thickness of the tungsten film. The uniformity (%) of the initial polishing rate was calculated by the following formula using the maximum polishing rate, the minimum polishing rate, and the average polishing rate in the fifth wafer surface (121 points) from the start of polishing. The uniformity (%) of the polishing rate of the wafer after 60 hours was calculated in the same manner.
Uniformity (%) = {(maximum polishing rate−minimum polishing rate) / 2} × average polishing rate × 100
As polishing conditions, a slurry obtained by adding 2% by weight of aqueous hydrogen peroxide to a diluted solution obtained by diluting W2000 (manufactured by Cabot) twice with ultrapure water was added at a flow rate of 150 ml / min during polishing, and a polishing load of 5 psi. The rotation speed of the polishing platen was 120 rpm, and the rotation speed of the wafer was 120 rpm. Before polishing, the surface of the polishing pad was dressed for 20 seconds using a dresser (Asahi Diamond Co., Ltd., M100 type). The dressing conditions were a dress load of 10 g / cm ² , a polishing platen rotation speed of 30 rpm, and a dresser rotation speed of 15 rpm.

Example 1
[Production of light transmission region]
A polyester polyol (number average molecular weight 2400) 128 parts by weight composed of adipic acid, hexanediol and ethylene glycol and 30 parts by weight of 1,4-butanediol were mixed, and the temperature was adjusted to 70 ° C. To this mixed solution, 100 parts by weight of 4,4′-diphenylmethane diisocyanate previously adjusted to 70 ° C. was added and stirred for about 1 minute. Then, the mixed solution was poured into a container kept at 100 ° C. and post-cured at 100 ° C. for 8 hours to produce a polyurethane resin. Using the produced polyurethane resin, a light transmission region (polished surface side: 56 mm × 20 mm, polished back side: 55 mm × 19 mm, cross-sectional shape: trapezoid, thickness 1.25 mm) was produced by injection molding.

[Production of polishing area]
In a reaction vessel, 100 parts by weight of a polyether-based prepolymer (manufactured by Uniroyal Corporation, adiprene L-325, NCO concentration: 2.22 meq / g), and a silicon-based surfactant (manufactured by Toray Dow Corning Silicone, SH- 192) 3 parts by weight were mixed and the temperature was adjusted to 80 ° C. Using a stirring blade, the mixture was vigorously stirred for about 4 minutes so that bubbles were taken into the reaction system at 900 rpm. 26 parts by weight of 4,4′-methylenebis (o-chloroaniline) (Ihara Chemical amine, manufactured by Ihara Chemical Co.) previously melted at 120 ° C. was added thereto. Thereafter, stirring was continued for about 1 minute, and the reaction solution was poured into a pan-shaped open mold. When the fluidity of this reaction solution disappeared, it was put in an oven and post-cured at 110 ° C. for 6 hours to obtain a polyurethane foam block. This polyurethane foam block was sliced using a band saw type slicer (manufactured by Fecken) to obtain a polyurethane foam sheet (specific gravity: 0.86, D hardness: 52 degrees). Next, this sheet was subjected to surface buffing to a predetermined thickness using a buffing machine (Amitech Co., Ltd.) to obtain a sheet with adjusted thickness accuracy (sheet thickness: 1.27 mm). Concentric groove processing (groove width: 0.25 mm, groove depth: 0.45 mm, groove pitch: 1.5 mm) on the surface of the buffed sheet using a groove processing machine (manufactured by Toho Steel Machine Co., Ltd.) ) This sheet is punched to a size of 60 cm in diameter, and then the opening A is located about 12 cm from the center of the punched sheet (polished surface side: 56 mm × 20 mm, polished back side: 55 mm × 19 mm, cross-sectional shape: trapezoid) To form a polished region.

[Production of laminated polishing pad]
As shown in FIG. 2, a polishing layer was produced by temporarily fixing the light transmission region by fitting it into the opening A of the polishing region. On a support layer made of urethane foam (made by Nippon Hojo Co., Ltd., Nipplay EXT), 100 parts by weight of a crystalline polyester resin (manufactured by Toyobo Co., Ltd., Byron GM420), and two or more glycidyl groups in one molecule An o-cresol novolak-type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN4400) is laminated with an adhesive layer (thickness 50 μm) made of a polyester hot melt adhesive, and an infrared heater is used. The surface of the adhesive layer was heated to 150 ° C. to melt the adhesive layer. After that, the polishing layer is laminated on the melted adhesive layer using a laminating machine and pressed, the hot melt adhesive is cured and the polishing layer and the support layer are bonded together, and at the same time temporarily fixed light The transmission area was bonded to the adhesive layer and completely fixed. Thereafter, the support layer was cut to the size of the polishing layer. Then, a pressure sensitive double-sided tape (manufactured by 3M, 442JA) is attached to the other surface of the support layer using a laminating machine, and the support layer and the pressure sensitive double-sided tape in the region corresponding to the light transmission region are removed (opening A laminated polishing pad was prepared (by forming part B). No deformation occurred in the produced laminated polishing pad. The polyester hot melt adhesive had a melting point of 142 ° C., a specific gravity of 1.22, and a melt flow index of 21 g / 10 min.

Example 2
[Production of light transmission region]
Using the polyurethane resin produced in Example 1, a light transmission region (polished surface side: 56 mm × 20 mm, polished back side: 56 mm × 20 mm, cross-sectional shape: rectangular, thickness 1.25 mm) was produced by injection molding.

[Production of polishing area]
A polishing region was produced in the same manner as in Example 1 except that the opening A (polishing surface side: 56 mm × 20 mm, polishing back surface side: 56 mm × 20 mm, cross-sectional shape: rectangular) was formed in Example 1.

[Production of laminated polishing pad]
As shown in FIG. 3, the light transmission region is temporarily fixed by fitting the light transmission region into the opening A of the polishing region and bonding the surface of the polishing region and the surface of the light transmission region with a removable adhesive tape. A polishing layer was prepared. Thereafter, a laminated polishing pad was produced in the same manner as in Example 1. No deformation occurred in the produced laminated polishing pad.

Example 3
[Production of laminated polishing pad]
As shown in FIG. 4, the light transmission region prepared in Example 1 is fitted into the opening A of the polishing region manufactured in Example 1, and the surface of the polishing region and the surface of the light transmission region are separated with a releasable adhesive tape. By bonding, the light transmission region was temporarily fixed to produce a polishing layer. Thereafter, a laminated polishing pad was produced in the same manner as in Example 1. No deformation occurred in the produced laminated polishing pad.

Example 4
In Example 1, 100 parts by weight of a crystalline polyester resin (byron GM420, manufactured by Toyobo Co., Ltd.) and an o-cresol novolac type epoxy resin having two or more glycidyl groups in one molecule (Nippon Kayaku Co., Ltd.) EOCN4400), a laminated polishing pad was prepared in the same manner as in Example 1 except that a polyester hot melt adhesive containing 2 parts by weight was used. No deformation occurred in the produced laminated polishing pad. The polyester hot melt adhesive had a melting point of 140 ° C., a specific gravity of 1.24, and a melt flow index of 26 g / 10 min.

Example 5
In Example 1, 100 parts by weight of a crystalline polyester resin (byron GM420, manufactured by Toyobo Co., Ltd.) and an o-cresol novolac type epoxy resin having two or more glycidyl groups in one molecule (Nippon Kayaku Co., Ltd.) EOCN4400), a laminated polishing pad was produced in the same manner as in Example 1 except that a polyester hot melt adhesive containing 10 parts by weight was used. No deformation occurred in the produced laminated polishing pad. The polyester hot melt adhesive had a melting point of 145 ° C., a specific gravity of 1.19, and a melt flow index of 16 g / 10 min.

Comparative Example 1
[Production of light transmission region]
Using the polyurethane resin produced in Example 1, a light transmission region (polished surface side: 56 mm × 20 mm, polished back side: 56 mm × 20 mm, cross-sectional shape: rectangular, thickness 1.25 mm) was produced by injection molding.

[Production of polishing area]
A polishing region was produced in the same manner as in Example 1 except that the opening A (polishing surface side: 56 mm × 20 mm, polishing back surface side: 56 mm × 20 mm, cross-sectional shape: rectangular) was formed in Example 1.

[Production of laminated polishing pad]
On a support layer made of urethane foam (made by Nippon Hojo Co., Ltd., Nipplay EXT), 100 parts by weight of a crystalline polyester resin (manufactured by Toyobo Co., Ltd., Byron GM420), and two or more glycidyl groups in one molecule An o-cresol novolak-type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EOCN4400) is laminated with an adhesive layer (thickness 50 μm) made of a polyester hot melt adhesive, and an infrared heater is used. The surface of the adhesive layer was heated to 150 ° C. to melt the adhesive layer. Thereafter, the polishing layer was laminated on the melted adhesive layer using a laminating machine and pressed, the polishing layer and the support layer were bonded together, and the support layer was cut to the size of the polishing layer. Then, before the hot-melt adhesive is completely cured, the adhesive layer in the opening A is reheated to 150 ° C., and the light transmission region is fitted into the opening A and pasted on the adhesive layer. The hot melt adhesive was completely cured and fixed. Then, a pressure sensitive double-sided tape (manufactured by 3M, 442JA) is attached to the other surface of the support layer using a laminating machine, and the support layer and the pressure sensitive double-sided tape in the region corresponding to the light transmission region are removed (opening A laminated polishing pad was prepared (by forming part B). The produced laminated polishing pad was deformed. The polyester hot melt adhesive had a melting point of 142 ° C., a specific gravity of 1.22, and a melt flow index of 21 g / 10 min.

Reference example 1
In Example 1, 100 parts by weight of a crystalline polyester resin (byron GM420, manufactured by Toyobo Co., Ltd.) and an o-cresol novolac type epoxy resin having two or more glycidyl groups in one molecule (Nippon Kayaku Co., Ltd.) A laminated polishing pad was produced in the same manner as in Example 1 except that a polyester hot melt adhesive containing 1 part by weight was used. No deformation occurred in the produced laminated polishing pad. The polyester hot melt adhesive had a melting point of 139 ° C., a specific gravity of 1.25, and a melt flow index of 29 g / 10 min.

Reference example 2
In Example 1, 100 parts by weight of a crystalline polyester resin (byron GM420, manufactured by Toyobo Co., Ltd.) and an o-cresol novolac type epoxy resin having two or more glycidyl groups in one molecule (Nippon Kayaku Co., Ltd.) EOCN4400), a laminated polishing pad was prepared in the same manner as in Example 1 except that a polyester hot melt adhesive containing 18 parts by weight was used. No deformation occurred in the produced laminated polishing pad. The polyester hot melt adhesive had a melting point of 147 ° C., a specific gravity of 1.18, and a melt flow index of 15 g / 10 min.

  In the laminated polishing pads of Examples 1 to 5, the pad did not float even after polishing for 60 hours, the shear stress was as high as 800 N or more, and no interfacial peeling occurred in the adhesive layer. The uniformity of the polishing rate after 60 hours was also maintained at 20% or less, and the polishing rate was stable even after long-time polishing. On the other hand, the laminated polishing pad of Comparative Example 1 was deformed by reheating during production, and the uniformity of the polishing rate was poor from the beginning. In Reference Example 1, the pad floated after polishing for 5 hours, the initial shear stress was low, and the shear stress significantly decreased after 60 hours of polishing. Also, the uniformity of the polishing rate after 60 hours is very poor. In Reference Example 2, the pad was lifted after polishing for 1 hour, and the polishing was interrupted after 3 hours of polishing because the pad was lifted and the wafer was cracked. Also, the initial shear stress was considerably low, and the shear stress decreased greatly after 3 hours of polishing.

1: Laminated polishing pad 2: Polishing surface plate 3: Abrasive (slurry)
4: Material to be polished (semiconductor wafer)
5: Support base (polishing head)
6, 7: Rotating shaft 8: Polishing region 9: Opening A
10: Light transmission region 11: Removable adhesive tape 12: Adhesive member 13: Support layer 14: Double-sided tape 15: Opening B

Claims (7)

A step of temporarily fixing a light transmission region in the opening A of the polishing region to produce a polishing layer, a step of providing an adhesive member containing a hot-melt adhesive heated and melted between the polishing layer and the support layer, and A method for producing a laminated polishing pad, comprising a step of curing the hot melt adhesive to bond the polishing layer and a support layer. The laminated polishing pad according to claim 1, wherein the temporary fixing is performed by fitting a light transmission region having the same shape as the opening A into an opening A that is narrowed from the polishing surface side toward the polishing back surface side. Manufacturing method. The method for manufacturing a laminated polishing pad according to claim 1 or 2, wherein the temporary fixing is performed by fitting a light transmission region in the opening A and bonding the surface of the polishing region and the surface of the light transmission region with a removable adhesive tape. . The adhesive member is an adhesive layer containing a polyester-based hot melt adhesive, or a double-sided tape having the adhesive layer on both sides of a substrate, and the polyester-based hot melt adhesive is a polyester resin 100 that is a base polymer. The manufacturing method of the laminated polishing pad in any one of Claims 1-3 which contain 2-10 weight part of epoxy resins which have two or more glycidyl groups in 1 molecule with respect to a weight part. The method for producing a laminated polishing pad according to claim 4, wherein the polyester resin is a crystalline polyester resin. A laminated polishing pad obtained by the production method according to claim 1. A method for manufacturing a semiconductor device, comprising a step of polishing a surface of a semiconductor wafer using the laminated polishing pad according to claim 6.