TW201922502A - Polishing pad and method for manufacturing polishing pad capable of realizing more precise polishing - Google Patents

Abstract

The present invention provides a polishing pad for realizing more precise polishing. The polishing pad according to an embodiment of the present invention comprises a substrate and a polishing layer. The polishing layer is disposed on the substrate. The polishing layer has a polyurethane resin and microspheres. The microspheres are dispersed in the polyurethane resin, and each of the microspheres has an outer casing made of a thermoplastic resin and has an average particle diameter of 20 [mu]m or less. With such polishing pad, since the average particle diameter of the microspheres included in the polishing layer is 20 [mu]m or less, the object to be polished can be more precisely polished by the polishing layer, and thereby the reliability is higher.

Description

Method for manufacturing polishing pad and polishing pad

The present invention relates to a polishing pad for polishing an object, and a method of manufacturing the polishing pad.

A polishing pad is used for polishing an optical material, a semiconductor device, or a substrate for a hard disk. The polishing pad has a synthetic resin such as a polyurethane, and a void is formed in the synthetic resin. At the time of polishing, the void is opened on the surface of the polishing pad, and the polishing object is polished by holding the polishing slurry in the opening.

As a method of forming the voids, there is a method of expanding the unexpanded heat-expandable microspheres which are mixed in the resin in the resin (for example, refer to Patent Documents 1 and 2). For example, Patent Document 1 discloses that a heat-expandable microsphere having a particle diameter of 20 μm or more is used, and the heat-expandable microsphere is expanded in a resin to a gap of about 150 μm to form a void to obtain a low-density polishing pad. . On the other hand, in Patent Document 2, it is disclosed that an unexpanded liquid-filled polymer microsphere (heat-expandable microsphere) is mixed with pre-expanded liquid-filled polymer microspheres to cause an unexpanded liquid to be filled and polymerized. The microspheres are expanded to 1000 to 10000% (average diameter of 20 to 150 μm) in the resin to obtain a low-density, high-voiding polishing pad.

Further, the polishing pad further includes a substrate and an adhesive layer provided between the substrate and the polishing layer in addition to the polishing layer. When the polishing pad of the laminated structure type is infiltrated during polishing, the slurry penetrates from the side of the polishing layer or the polishing pad to the adhesive layer or the buffer layer, and peeling occurs between the polishing layer and the buffer layer.

In view of this, there is a technique in which a layer called a water stop layer is provided between the polishing layer and the adhesive layer to prevent penetration of the slurry into the buffer layer (for example, refer to Patent Document 3). Alternatively, the surface roughness of the back surface of the polishing layer is controlled to be 1 μm or less, and the interface between the polishing layer and the adhesive layer is eliminated, and the penetration of the slurry into the interface is suppressed (for example, refer to Patent Document 4).
[Previous Technical Literature]
[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2010-274362. Patent Document 2: Japanese Patent Laid-Open No. Hei. No. Hei. No. Hei. No. Hei. Bulletin

[The problem that the invention wants to solve]

In the above Patent Documents 1 and 2, the heat-expandable microspheres are largely expanded to obtain a low-density polishing pad. In the polishing pad, there is a demand for high density and small bubble diameter (20 μm or less) in accordance with the diversification and high precision of the object to be polished. However, the expanded microspheres are only commercially available products of 20 μm or more, and the heat-expandable microspheres are easily expanded to 20 μm or more by the reaction heat of the mixed resin, and it is difficult to manufacture a polishing pad having a bubble diameter of 20 μm or less. .

Further, as described in the above Patent Documents 3 and 4, if a water stopping layer is provided in addition to the polishing layer, the substrate, and the adhesive layer, or the back surface of the polishing layer is subjected to surface treatment, the number of parts or the number of manufacturing steps is increased and the polishing pad is Manufacturing costs become higher.

In view of the above circumstances, an object of the present invention is to provide a highly reliable polishing pad and polishing pad which achieves more precise polishing and suppresses an increase in manufacturing cost and prevents a decrease in peel strength caused by penetration of a slurry during polishing. Production method.
[Technical means to solve the problem]

In order to achieve the above object, a polishing pad according to an aspect of the present invention includes a substrate and a polishing layer. The polishing layer is provided on the substrate. The polishing layer has a polyurethane resin and a microsphere which is dispersed in the above-mentioned polyurethane resin and has an outer shell made of a thermoplastic resin. The above microspheres have an average particle diameter of 20 μm or less.
In the case of such a polishing pad, since the average particle diameter of the microspheres included in the polishing layer is 20 μm or less, the polishing object can be more precisely polished by the polishing layer, thereby providing a polishing pad having higher reliability.

In the above polishing pad, the polishing layer may have a density of 0.6 g/cm ³ or more and 0.9 g/cm ³ or less.
In the case of such a polishing pad, since the density of the microspheres contained in the polishing layer is 0.6 g/cm ³ or more and 0.9 g/cm ³ or less, the polishing object can be more precisely polished by the polishing layer.

In the above polishing pad, the microspheres are heated and expandable spheres, and the average particle diameter before heating may be 5 μm or more and 20 μm or less.
In the case of such a polishing pad, the average particle diameter of the microspheres contained in the polishing layer can be suppressed to 20 μm or less even if the heat-expandable sphere is expanded, and the object to be polished can be more precisely polished by the polishing layer.

In the polishing pad, the microspheres dispersed in the polyurethane resin may have an average particle diameter of 10 or more and 20 μm or less.
In the case of such a polishing pad, since the average particle diameter of the microspheres included in the polishing layer is 10 μm or more and 20 μm or less, the polishing target can be more precisely polished by the polishing layer.

In the polishing pad, the microspheres present per unit volume of the polishing layer may be 50,000 or more. The volume fraction of the microspheres in the polishing layer may be 20% or less.
In the case of such a polishing pad, since the number of microspheres per unit volume of the polishing pad is 50,000 or more, and the volume fraction of the microspheres in the polishing pad is 20% or less, the polishing layer can be more precisely ground by the polishing layer. The object is ground.

In the polishing pad, the polishing layer may have a first main surface on the substrate side and a second main surface that forms a polishing surface on the opposite side of the substrate. The first main surface is composed of a surface of the urethane resin and an inner wall surface of the microspheres which are cut along the surface of the urethane resin. The double-sided tape may include a hot-melt adhesive layer provided between the substrate and the polishing layer and in contact with the surface of the polyurethane resin and the inner wall surface of the microsphere.
In the case of such a polishing pad, since the void of the polishing layer is an independent bubble composed of a microsphere having a casing, it is difficult for the slurry to penetrate into the polishing layer. Further, since the hot-melt adhesive layer of the double-sided tape is in contact with the surface of the urethane resin of the polishing layer and the inner wall surface of the microsphere, the substrate and the polishing layer are firmly adhered by the anchoring effect.

In the above polishing pad, the hot-melt adhesive layer may be an acrylic resin.
In the case of such a polishing pad, since the hot-melt adhesive layer is an acrylic resin, the hot-melt adhesive layer is firmly adhered to the polishing layer.

In the above polishing pad, the substrate may be a non-woven material, and the adhesive layer on the substrate side of the double-sided tape may be a pressure-sensitive adhesive layer.
In the case of such a polishing pad, the substrate is firmly adhered to the double-sided tape.

In order to achieve the above object, a method for producing a polishing pad according to an aspect of the present invention includes preparing a liquid containing microspheres and a prepolymer having an outer diameter of 5 μm or more and 20 μm or less and having an outer shell made of a thermoplastic resin. The hardener is mixed in the above liquid to form an abrasive. The polishing layer is formed by adjusting the average particle diameter so that the average particle diameter of the microspheres is one time or more and less than four times.
In the method of producing such a polishing pad, even if the heat-expandable sphere is expanded, the polishing layer is formed while suppressing the expansion of the microspheres so that the average particle diameter of the microspheres is doubled or more and less than 4 times. Therefore, the average particle diameter of the microspheres contained in the polishing layer can be suppressed to 20 μm or less, and the object to be polished can be more precisely polished by the polishing layer.

In the method for producing a polishing pad, in the step of preparing the liquid, the microspheres and the prepolymer may be mixed at 80 ° C or lower. In the step of forming the polishing layer, the temperature of the mold used for curing the abrasive material may be 100 ° C or less, and the time required for curing the abrasive material may be less than 150 seconds.
In the method of producing such a polishing pad, even if the heat-expandable sphere is expanded, the average particle diameter of the microspheres contained in the polishing layer can be reliably suppressed to 20 μm or less, and the polishing layer can be more precisely ground by the polishing layer. The object is ground.
[Effects of the Invention]

As described above, according to the present invention, it is possible to provide a polishing pad and a method of manufacturing the polishing pad which are more reliable.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings, the XYZ axis coordinates are sometimes introduced.

(First embodiment)

[Summary of polishing pad]
Fig. 1(a) is a schematic perspective view showing a polishing pad 100A of the first embodiment.

The polishing pad 100A includes a polishing layer 101, an adhesion layer 102, and a buffer layer 103.

The polishing layer 101 is a layer that is in contact with the object to be polished and polished. Hereinafter, the surface of the polishing layer 101 is referred to as a polishing surface 101a. Grooves and holes (not shown) for making the flow of the slurry liquid good may be formed on the polishing surface 101a.

Next, layer 102 is a layer that follows polishing layer 101 and buffer layer 103, such as an adhesive tape.

The buffer layer 103 is a base material of the polishing pad 100A, and is a layer in which the polishing layer 101 is more uniformly abutted against the object to be polished. The buffer layer 103 can be made of a flexible material such as a nonwoven fabric or a synthetic resin.

The polishing pad 100A is attached to the polishing apparatus by an adhesive tape or the like disposed on the buffer layer 103. The size (diameter) of the polishing pad 100A can be determined according to the size of the polishing apparatus, etc., and can be, for example, about 10 cm to 1 m in diameter. Further, the shape of the polishing pad 100A is not limited to a disk shape, and may be a belt shape or the like.

The polishing pad 100A is rotationally driven while being pressed against the object to be polished by the polishing device, and the object to be polished is polished. At this time, a slurry liquid is supplied between the polishing pad 100A and the object to be polished. The slurry liquid is supplied to the polishing surface 101a via a groove or a hole and discharged.

[Composition of the polishing layer]
Fig. 1(b) is a schematic cross-sectional view of the polishing pad 100A of the first embodiment.

In the polishing pad 100A, the polishing layer 101 includes a polymer 110 and microspheres 111. The polishing layer 101 is provided on the buffer layer 103 via the adhesion layer 102. The density of the polishing layer 101 is 0.6 g/cm ³ or more and 0.9 g/cm ³ or less. Further, the microspheres in the present embodiment are not limited to spheres whose outer peripheral surface is a true spherical surface, and also include a sphere having a spherical surface whose outer peripheral surface is slightly deformed. The number of microspheres 111 present per unit volume of the polishing layer 101 is 50,000 or more. The volume fraction of the microspheres 111 in the polishing layer 101 is 20% or less.

The polymer 110 is the main constituent material of the abrasive material. The polymer 110 can be a polymer formed by polymerization of a prepolymer and a hardener. Examples of such a polymer include a polyurethane resin and the like. The polyurethane is preferably used as the polymer 110 because it has good availability and processability and has preferable polishing characteristics.

The prepolymer may be a compound having an isocyanate group terminal (hereinafter referred to as an isocyanate compound) which is obtained by reacting a polyisocyanate compound with a polyol compound under normal use conditions, and is contained in the molecule. Polyurethane bond and isocyanate group. Further, the isocyanate compound containing a polyurethane bond may contain other components insofar as the effects of the present invention are not impaired.

The polyisocyanate compound means a compound having two or more isocyanate groups in the molecule, and for example, methylphenyl diisocyanate, diphenylmethane diisocyanate or the like can be used.

Further, examples of the polyisocyanate compound include: m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-methylphenylene diisocyanate (2,6-TDI), and 2,4-methylphenylene diisocyanate (2). , 4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyldiisocyanate, 3, 3'-Dimethyldiphenylmethane-4,4'-diisocyanate, benzodimethyl-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, six Methylene diisocyanate (HDI), isophorone diisocyanate, propyl-1,2-diisocyanate, butyl-1,2-diisocyanate, cyclohexyl-1,2-diisocyanate, extens Cyclohexyl-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), p-phenylene isothiocyanate, benzodimethyl-1,4-diisothiocyanate Ester and hypoethyl diisothiocyanate. One type or two or more types may be used.

Further, the polyol compound means a compound having two or more alcoholic hydroxyl groups (OH) in the molecule, and for example, poly(oxytetramethylene) glycol (or polytetramethylene ether glycol) (PTMG) can be used. ), polypropylene glycol (PPG), diethylene glycol (DEG), and the like.

Further, examples of the polyol compound include a diol compound such as ethylene glycol or butylene glycol, a triol compound, and the like; a polyether polyol compound such as PTMG; a reaction product of ethylene glycol with adipic acid or butanediol; A polyester polyol compound such as a reactant of adipic acid; a polycarbonate polyol compound, a polycaprolactone polyol compound, or the like. One type or two or more types may be used.

A polyamine-based hardener can be used as the hardener. The polyamine-based curing agent is a substance having two or more amine groups, and an alkylenediamine such as ethylenediamine, propylenediamine or hexamethylenediamine; isophorone diamine and dicyclohexyl can be used. a diamine having an aliphatic ring such as methane-4,4'-diamine; a diamine having an aromatic ring such as MOCA (3,3-dichloro-4,4-diaminodiphenylmethane); Hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2 a diamine having a hydroxyl group such as hydroxypropylethylenediamine, particularly a hydroxyalkylalkylene diamine; and the like. Further, a trifunctional triamine compound or a tetrafunctional or higher polyamine compound can also be used.

Further, a polyhydric alcohol-based curing agent can also be used as the curing agent. The polyol-based curing agent is a material having two or more hydroxyl groups, and may be, for example, ethylene glycol or a polyether polyol.

Further, examples of the polyol-based curing agent include low molecular weight polyol compounds such as butanediol and hexanediol, and polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol (PTMG), and bisphenol. a polyether polyol compound such as a reaction product of A with propylene oxide, a reaction product of ethylene glycol with adipic acid, a polyester polyol compound such as a reaction product of butanediol and adipic acid, a polycarbonate polyol compound, and A high molecular weight polyol compound such as a polycaprolactone polyol compound.

As the curing agent, one or more of a polyamine-based curing agent and a polyol-based curing agent can be used.

Here, the components are mixed such that the equivalent ratio of the amine group or the hydroxyl group active hydrogen group present in the curing agent to the isocyanate group present at the terminal of the prepolymer is 0.70 to 1.20. The R value is preferably from 0.70 to 1.20, more preferably from 0.80 to 1.00, still more preferably from 0.85 to 0.95. An excess of the isocyanate group is used for the crosslinking reaction described later by setting the R value to 1 or less.

The microspheres 111 are dispersed in the polymer 110. The microspheres 111 are spherical objects having a shell shape. The hemispherical microspheres 111 exposed on the polishing surface 101a are exposed by the cutting process after forming the polishing layer 101. The average particle diameter of the microspheres 111 is 10 μm or more and 20 μm or less. More preferably, the average particle diameter of the microspheres 111 can be set to be 10 μm or more and less than 20 μm. The particle diameter or the number of the microspheres 111 are calculated based on, for example, a laser diffraction type particle size distribution measuring apparatus, X-ray CT (Computed Tomography), an electron microscope image, or the like.

Fig. 1 (c) is a schematic cross-sectional view of the microsphere 111 of the first embodiment.

The microsphere 111 has a spherical shell-shaped outer casing 111a containing a thermoplastic resin and an inner space 111b surrounded by the outer casing 111a. As the thermoplastic resin, for example, vinylidene chloride or acrylonitrile can be used. The microspheres 111 are coated with a low boiling hydrocarbon by a shell of a thermoplastic resin. The microspheres 111 are heated and expandable spheres, and a heat-expandable sphere having an average particle diameter before heating of 5 μm or more and 20 μm or less is used.

The microspheres 111 inhibit swelling by adjustment of reaction conditions in the polymerization of the prepolymer. For example, the heat of reaction generated by the polymerization reaction is rapidly cooled, or the polymerization of the prepolymer is rapidly promoted to forcibly suppress the expansion by the polymer existing around the microspheres 111. Alternatively, the microspheres 111 may be slightly expanded by the heat of generation accompanying the formation reaction of the polyurethane. However, the average particle diameter of the microspheres 111 included in the polishing layer 101 is adjusted to be 10 μm or more and 20 μm or less. For example, the microspheres 111 dispersed in the polymer 110 have an average particle diameter of 15 μm.

In the microsphere 111, the outer casing 111a is filled with a low boiling point hydrocarbon or the like. For example, the low boiling hydrocarbon is isobutane, pentane or the like.

Commercially available products can also be used for the microspheres 111. For example, a Matsumoto Microsphere series (manufactured by Matsumoto Oil & Fat Pharmaceutical Co., Ltd.) and an EXPANCEL series (manufactured by Akzo Nobel Co., Ltd.) can be used as the microspheres 111.

In the present embodiment, two or more kinds of microspheres 111 having different diameters can be used. The content ratio of the microspheres 111 in the polishing material is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 45% by volume or less, and still more preferably 15% by volume or more and 30% or more based on the polishing material. Below volume%. When the polishing layer 101 is worn by polishing, the microspheres 111 are exposed on the polishing surface 101a, which affects the polishing properties of the polishing surface 101a.

[Method of Manufacturing Polishing Pad]

Fig. 2 is a schematic view showing a manufacturing apparatus 200 for manufacturing the polishing pad 100A of the present embodiment.

The manufacturing apparatus 200 includes a first storage tank 201, a second storage tank 202, a stirring tank 203 (mixing container), a die 204, a container 212, a pump 401, a pump 402, a switching valve 410, a switching valve 420, a flow path 501a, and a flow path. 501b, flow path 501c, flow path 502a, flow path 502b, flow path 502c, and flow path 503.

The first storage tank 201 can accommodate the contents (liquid) including the microspheres 111 and the prepolymer. The microspheres 111 are previously housed in a container 212 provided above the first storage tank 201. The microspheres 111 are introduced into the first storage tank 201 from the container 212 via the flow path 503. By the microspheres 111 being introduced into the first storage tank 201 from the container 212 via the flow path 503, scattering of the microspheres 111 to the outside of the first storage tank 201 can be suppressed. The second storage tank 202 can accommodate a curing agent that hardens the prepolymer. The stirring tank 203 mixes the liquid containing the microspheres 111 and the prepolymer with the hardener to form the abrasive material 301.

By dispersing such resin-made microspheres 111 in the polishing layer 101, the size of the voids in the polishing layer 101 can be made uniform. Further, the polishing property of the polishing pad 100A can be adjusted by the amount of input of the microspheres 111.

The pump 401 can supply the liquid containing the microspheres 111 and the prepolymer from the first storage tank 201 to the stirring tank 203. The pump 401 is disposed in the middle of the flow path 501a. When the flow path 501a and the flow path 501b are communicated by the switching valve 410 and the pump 401 is actuated, the liquid containing the microspheres 111 and the prepolymer is supplied from the first storage tank 201 to the stirring tank 203 via the flow paths 501a and 501b.

The pump 402 can supply the hardener from the second storage tank 202 to the agitation tank 203. The pump 402 is disposed in the middle of the flow path 502a. When the flow path 502a is communicated with the flow path 502b by the switching valve 420 and the pump 402 is actuated, the hardener is supplied from the second storage tank 202 to the stirring tank 203 via the flow paths 502a and 502b.

Further, in the manufacturing apparatus 200, when the flow path 501a and the flow path 501c are communicated by the switching valve 410 and the pump 401 is actuated, the liquid containing the microspheres 111 and the prepolymer is stored in the first storage via the flow paths 501a and 501c. The tank 201 circulates with the pump 401. When the flow path 502a and the flow path 502c are communicated by the switching valve 420 and the pump 402 is actuated, the hardener circulates between the second storage tank 202 and the pump 402 via the flow paths 502a and 502c. The mold 204 receives the abrasive material 301 from the agitation tank 203, and forms the polishing layer 101 from the abrasive material 301.

Using such a manufacturing apparatus 200, for example, the prepolymer and the microspheres 111 are put into the first storage tank 201. The average particle diameter of the microspheres 111 before being introduced into the first storage tank 201 is 5 μm or more and 20 μm or less, and more preferably 5 μm or more and 15 μm or less. The prepolymer can be set as an isocyanate compound. The hardener is introduced into the second storage tank 202. The curing agent is either or both of a polyol-based curing agent and a polyamine-based curing agent. In order to stabilize the fluidity of each raw material, the first storage tank 201 and the second storage tank 202 are heated at a specific temperature. In order to suppress the expansion of the microspheres 111 as much as possible, the temperature of the first storage tank 201 is preferably 50° C. or higher and 80° C. or lower. If it is set to a temperature higher than 80 ° C, there is a possibility that the microspheres 111 expand.

Next, the contents of the first storage tank 201 (hereinafter referred to as the first solution) are sent from the first storage tank 201 to the stirring tank 203 through the flow path 501a, the pump 401, the switching valve 410, and the flow path 501b. The contents of the second storage tank 202 (hereinafter referred to as the second solution) are sent from the second storage tank 202 to the stirring tank 203 through the flow path 502a, the pump 402, the switching valve 420, and the flow path 502b. Thereby, a fluid-like abrasive 301 in which the first solution and the second solution are mixed is formed in the stirring tank 203.

Next, the abrasive 301 is poured into the mold 204 to be cast. In the abrasive material 301 in the mold 204, the prepolymer is polymerized with the hardener. Here, as the polymerization proceeds, the mixture hardens to form a mass comprising the polymer. At this time, the reaction conditions were controlled, and the average particle diameter of the microspheres 111 after the polymerization reaction was adjusted while the polishing material 301 was hardened. Further, since the microspheres 111 may expand due to the temperature of the mold 204, the temperature of the mold 204 is preferably 60 ° C or more and 100 ° C or less. When the temperature is 60 ° C or lower, the progress of the polymerization reaction is hindered, and if the temperature is higher than 100 ° C, the microspheres 111 may expand.

For example, in the present embodiment, the polymerization reaction of the prepolymer is rapidly promoted by the application period (the time until the curing is performed until the polymerization is carried out) within 150 seconds, so that the expansion speed of the microspheres 111 is faster. The viscosity of the mixture is increased by the polymerization reaction, and the average particle diameter of the microspheres 111 after the polymerization reaction is equal to or more than 1 times the average particle diameter of the microspheres 111 before the microspheres 111 are introduced into the first storage tank 201. The polishing layer 101 is formed in a manner of up to 4 times. The average particle diameter of the microspheres 111 is adjusted to be 10 μm or more and 20 μm or less. Thereby, the density of the polishing layer 101 is adjusted to 0.6 g/cm ³ or more and 0.9 g/cm ³ or less. In view of controlling the expansion of the microspheres 111, the pot life is preferably 60 seconds or more and 150 seconds or less.

Further, the polishing layer 101 is obtained by slicing a block. The polishing layer 101 is laminated with the layer 102 and the buffer layer 103 and cut into a desired shape to form a polishing pad 100A. A groove or the like may be formed in the polishing layer 101 as needed.

Further, the microspheres 111 are fine particles. When the microspheres 111 are introduced into the first storage tank 201 from above the first storage tank 201, the microspheres 111 fly in the first storage tank 201 and adhere to the first 1 The possibility of the inner wall of the storage tank 201. As a result, there is a possibility that the microspheres 111 cannot be efficiently dispersed in the prepolymer. Therefore, the microspheres 111 can also be introduced through the flow path from the lower side of the first storage tank 201. Thereby, the microspheres 111 are directly introduced into the first storage tank 201, and are directly mixed into the prepolymer accumulated in the bottom of the first storage tank 201.

The microspheres 111 can also be introduced into the second storage tank 202. In this case as well, the microspheres 111 can be introduced into the second storage tank 202 by the flow path from the lower side of the second storage tank 202, similarly to the method of inputting to the first storage tank 201.

In the case of the polishing pad 100A manufactured by such a method, the average particle diameter of the microspheres 111 included in the polishing layer 101 is controlled to be 10 μm or more and 20 μm or less, and the density of the polishing layer 101 is adjusted to 0.6 g/cm ^{3 .} The above is 0.9 g/cm ³ or less, whereby the object to be polished can be polished more precisely than the polishing layer in which the microspheres 111 having an average particle diameter of more than 20 μm are dispersed. Further, the polishing rate by the polishing pad 100A is also improved.

Further, in the present embodiment, since the average particle diameter of the microspheres 111 included in the first solution is 5 μm or more and 20 μm or less, the first solution passes through the flow path 501a, the pump 401, the switching valve 410, and the flow path. The fluidity of the first solution at 501b is improved. Thereby, clogging of the first solution in each of the flow path 501a, the pump 401, the switching valve 410, and the flow path 501b can be suppressed. As a result, foreign matter does not easily remain in the abrasive material 310.

(Second embodiment)

[Composition of polishing pad]
Fig. 3 is a schematic cross-sectional view showing the polishing pad 100B of the second embodiment. In Fig. 3, an enlarged view of the interface between the polishing layer 101 and the double-sided tape 102 and an enlarged view of the microspheres 111 are shown.

The polishing pad 100B includes a polishing layer 101, a double-sided tape 102 as an adhesive layer, and a buffer layer 103.

The double-sided tape 102 is a layer in which the polishing layer 101 and the buffer layer 103 are followed.

In the polishing pad 100B, the polishing layer 101 includes a polymer 110 and microspheres 111. The polishing layer 101 is provided on the buffer layer 103 via the double-sided tape 102. In the polishing layer 101, the surface on the buffer layer 103 side is referred to as a first main surface 101d, and the surface on which the polishing surface is formed on the side opposite to the buffer layer 103 is referred to as a second main surface 101u. Each of the first main surface 101d and the second main surface 101u is composed of a surface 110s of the polymer 110 and an inner wall surface 111w of the microsphere 111. Further, the microspheres in the present embodiment are not limited to spheres whose outer peripheral surface is a true spherical surface, and also include a sphere having a spherical surface whose outer peripheral surface is slightly deformed.

The double-sided tape 102 has a substrate 125 and adhesive layers 120 and 121 provided on both sides of the substrate 125. The adhesive layer 120 is disposed between the substrate 125 and the polishing layer 101. The adhesive layer 121 is disposed between the substrate 125 and the buffer layer 103. The adhesive layer 120 is a hot-melt adhesive layer, and the adhesive layer 121 may be a hot-melt adhesive layer or an adhesive layer of another kind (for example, a pressure sensitive type). In the case where a non-woven fabric material is used as the buffer layer 103, if the adhesive layer 121 is a hot-melt adhesive layer, when the slurry liquid penetrates into the buffer layer, the force is extremely lowered, so that it is preferable to use the pressure-sensitive type. Followers and so on.

The hot-melt adhesive layer contains a thermoplastic resin, and includes, for example, an acrylic resin, an ethylene-vinyl acetate resin, an olefin resin, a synthetic rubber resin, a polyamide resin, and a polyester resin. The component of the subsequent agent layer 120 is not limited to one component, and may be a mixed type containing two or more liquids. Further, the adhesive layer 121 on the side of the buffer layer 103 is not limited to the hot-melt adhesive layer, and may be a rubber-based adhesive, an anthrone-based adhesive, an urethane-based adhesive, or an epoxy-based adhesive. And an adhesive layer such as a styrene-diene block copolymer-based adhesive.

The substrate 125 is a substrate of the double-sided tape 102. The base material 125 includes, for example, a polyimide resin, a polyester resin, a polyurethane resin, a polyethylene resin, a polypropylene resin, a cellulose resin, a polyvinyl chloride resin, and a polyvinylidene second. A vinyl chloride resin, a polyvinyl alcohol resin, an ethylene-vinyl acetate copolymer resin, a polystyrene resin, a polycarbonate resin, an acrylic resin, or a laminate resin of two or more kinds thereof.

The microspheres 111 are dispersed in the polymer 110. The microspheres 111 are spherical objects having a shell shape. The microsphere 111 has a hemispherical shape on the first main surface 101d and the second main surface 101u (polishing surface 101a) of the polishing layer 101, and the inner wall thereof is exposed. The hemispherical microspheres 111 are formed by cutting the surface of the polymer 110 together with the polymer 110 after the block-shaped polishing layer 101 is formed.

In the polishing pad 100B, the adhesive layer 120 is in close contact with the substrate 125 and is in close contact with the first main surface 101d of the polishing layer 101. For example, the adhesive layer 120 is in contact with the surface 110s of the polymer 110 and the inner wall surface 111w of the microsphere 111. That is, the adhesive layer 120 is in contact with the surface 110s of the polymer 110 in the first main surface 101d, and also enters the inside of the microsphere 111.

[Method of Manufacturing Polishing Pad]

The sheet-shaped polishing layer 101 is obtained by slicing the block-shaped polishing layer 101 formed by the manufacturing apparatus 200 shown in FIG. At this time, the microspheres 111 exposed on the main faces 101u and 101d of the polishing layer 101 are cut, and the inner wall faces 111w of the microspheres 111 are exposed on the main faces 101u and 101d of the polishing layer 101. The inner wall surface 111w is exposed by evaporation from the cut microspheres 111 or release of low boiling hydrocarbons into the air.

4(a) and 4(b) are schematic views showing a step of bonding the polishing layer 101 and the buffer layer 103.

As shown in FIG. 4(a), after the polishing layer 101, the double-sided tape 102, and the buffer layer 103 which are sliced into a sheet shape are prepared, the polishing layer 101 and the buffer layer 103 are opposed to each other, and the double-sided tape 102 is placed in the polishing. Between the layer 101 and the buffer layer 103. Further, in the examples of FIGS. 4(a) and 4(b), the adhesive layer 120 is a hot-melt adhesive layer, and the adhesive layer 121 is a pressure-sensitive adhesive layer.

First, by pressing the double-sided tape 102 and the buffer layer 103, the adhesive layer 120 of the double-sided tape 102 and the polishing layer 101 are subsequently heated, and then a laminate (hot melt type) is formed.

At this time, by heating, the fluidity and adhesiveness of the adhesive layer 120 increase, the adhesive layer 120 is in close contact with the polishing layer 101, and the adhesive layer 121 is in close contact with the buffer layer 103. At this time, on the first main surface 101d, the adhesive layer 120 is bonded to the surface 110s of the polymer 110, and enters into the microsphere 111, and is also connected to the inner wall surface 111w of the microsphere 111 (see FIG. 3).

The heating temperature is set, for example, to 80 ° C or more and 110 ° C or less. Further, at the time of heating, pressure may be applied from the direction in which the polishing layer 101 faces the double-sided tape 102 and from the buffer layer 103 toward the double-sided tape 102 as needed. At this time, since the microspheres 111 are surrounded by the polymer 110 due to the outer periphery thereof, thermal expansion or deformation is less likely to occur.

After the polishing layer 101 and the buffer layer 103 are followed by the double-sided tape 102, the laminated body is cut into a desired shape (for example, a disk shape) to form a polishing pad 100B as shown in FIG.

In the case of such a polishing pad 100B, since the void of the polishing layer 101 is an independent bubble composed of the microspheres 111 having the outer casing 111a, the slurry cannot enter the inside of the polishing layer 101 through the microspheres 111. Thereby, the slurry cannot penetrate from the second main surface 101u of the polishing layer 101 to the first main surface 101d. That is, the slurry cannot reach the double-sided tape 102 from the second main surface 101u of the polishing layer 101.

Further, in the case of the polishing pad 100B, the inner wall surface of the plurality of microspheres 111 to which the hot-melt adhesive of the double-sided tape 102 is attached can be provided, and the double-sided tape 102 can be more closely adhered to the polishing layer 101. For example, since the adhesive layer 120 of the double-sided tape 102 is in contact with the surface 110s of the polymer 110 of the polishing layer 101 and the inner wall surface 111w of the microsphere 111, an anchoring effect acts between the polishing layer 101 and the double-sided tape 102. The polishing layer 101 is firmly adhered to the double-sided tape 102. Thereby, the polishing layer 101 is less likely to be peeled off from the double-sided tape 102.

In particular, in the polishing layer 101 of the present embodiment, the adhesive layer 120 enters into the fine microspheres 111 having an average particle diameter of 20 μm or less (for example, 15 μm) in the first main surface 101d. Thereby, the anchoring effect is further promoted, and the peeling strength of the polishing layer and the adhesive layer becomes large.

Further, since the first main surface 101d of the polishing layer 101 is composed of the surface 110s of the polymer 110 and the inner wall surface 111w of the microsphere 111, the surface area of the first main surface 101d and the surface 110s of only the polymer 110 are formed. It is bigger than it is. Thereby, the contact area of the adhesive layer 120 with respect to the first main surface 101d is increased, and the adhesion of the adhesive layer 120 to the polishing layer 101 is improved.

Further, in the present embodiment, it is not necessary to provide a water stop layer between the polishing layer 101 and the double-sided tape 102. Thereby, the manufacturing cost of the polishing pad is suppressed from increasing. Further, even if a water stop layer is provided between the polishing layer 101 and the double-sided tape 102, when the gap of the polishing layer is not constituted by the microspheres 111, there is a penetration of the slurry from the polishing layer between the polishing layer and the double-sided tape. There is a possibility that the adhesion between the polishing layer and the water stop layer may decrease.

Further, in the present embodiment, the surface roughness (Ra) of the first main surface 101d of the polishing layer 101 need not be prepared to be 1 μm or less. Thereby, it is possible to suppress an increase in the manufacturing cost of the polishing pad. In the present embodiment, in order to make the adhesive layer 120 firmly adhere to the polishing layer 101 by the anchoring effect, there is almost no gap between the polishing layer 101 and the double-sided tape 102, so that the slurry can be effectively prevented from being applied to the interface. Infiltration.

Further, in the polishing pad 100B, the average particle diameter of the microspheres 111 included in the polishing layer 101 is controlled to 20 μm or less (for example, 15 μm), and the density of the polishing layer 101 is adjusted to 0.6 g/cm ³ or more and 0.9 g. /cm ³ or less. Thereby, the object to be polished can be polished more precisely than the polishing layer in which the microspheres 111 having an average particle diameter of 20 μm or more are dispersed. Further, the polishing rate by the polishing pad 100B is also increased.

Further, in the present embodiment, since the average particle diameter of the microspheres 111 included in the first solution is 5 μm or more and less than 20 μm, the first solution passes through the flow path 501a, the pump 401, the switching valve 410, and the flow path. The fluidity of the first solution at 501b is improved. Thereby, clogging of the first solution in each of the flow path 501a, the pump 401, the switching valve 410, and the flow path 501b can be suppressed. As a result, foreign matter does not easily remain in the abrasive 301.
[Examples]

[Example 1]

Hereinafter, the microspheres 111 having different average particle diameters are formed on the polishing layer 101 made of the same polyurethane resin, and comparative studies are carried out. The average particle diameter of the microspheres 111 of the examples and comparative examples is shown in Table 1. The average particle diameter is calculated by an X-ray CT apparatus to be described later.

[Table 1]

In the examples and comparative examples, the polishing layer 101 was formed under the same conditions except for the average particle diameter of the microspheres 111. The method of measuring the average particle diameter, the number, the occupied volume ratio, and the like of the microspheres 111 per unit volume measured by X-ray CT and the polishing rate are as follows.

<X-ray CT device>
Measuring device: three-dimensional measuring X-ray CT device TDM1000H-II (2K) (manufactured by Yamato Scientific Co., Ltd.)
・Analysis software: VGStudio MAX3.0 (made by VG ACADEMY)
・Magnification axis: 10 mm

An X-ray CT image (measurement volume of about 1 mm ³ ) was obtained by taking an X-ray CT apparatus and cutting the polishing pad by 3 mm square and fixing it by an adhesive tape. The captured X-ray CT image is read into the analysis software, and the porous structure is analyzed for a portion corresponding to a volume of about 0.5 mm ^{3 to} obtain the total volume and number of the cavity portions of the microspheres 111 in the sample. . The diameter of each microsphere 111 was calculated as the average particle diameter based on the total volume and number of the obtained microspheres 111, and the number of microspheres per unit volume in the polishing pad and the occupied volume ratio were calculated.

In addition, there is a method of measuring the average particle diameter of the microspheres 111 by surface observation using a scanning electron microscope or the like, but it is possible to measure only the size of the cut surface of the microspheres 111 in the surface observation. It is smaller than the diameter of the actual microsphere 111, so it is difficult to determine the correct value. Moreover, in such surface observation, it is difficult to measure in the state in which the cut surface is crushed or the surface is ground. Therefore, in the present embodiment and the comparative example, the diameter of the cavity portion obtained by using the X-ray CT apparatus is set to be the average particle diameter of the microspheres 111, and the diameter of the microspheres 111 is closer to the actual diameter of the microspheres 111. value.

<grinding test>
Using a grinder: manufactured by Ebara Seisakusho Co., Ltd., F-REX300
Grinding disc: manufactured by Asahi Diamond Industry Co., Ltd., C100
Number of rotations: (platen) 70 rpm, (top ring) 71 rpm
Grinding pressure: 3.5 psi
Abrasive temperature: 20 ° C
Abrasive spray volume: 200 ml/min

<Abrased material and abrasive>
(TEOS (tetraethoxysilane) film grinding)
Use workpiece (abrasive): at 12 inches Substrate polishing by plasmon CVD (Plasma Enhanced-Chemical Vapor Deposition) to form tetraethoxy decane by a thickness of 1 μm. Agent: Cabot company, product number: SS25 (using stock solution: pure water = 1:1 mixture)
(Cu film grinding)
Workpiece (abrasive): Cu-plated substrate abrasive: Cu slurry manufactured by Cabot

The results are shown in Table 2. The polishing rate is expressed by the thickness (nm) of the amount of grinding per minute. The thickness of the TEOS film or the Cu film on the wafer after the polishing was measured at 121 locations, and the average value of the thickness to be polished was determined. The polishing rate (nm/min) was determined by dividing the average value of the thickness to be polished by the polishing time. On the TEOS film substrate and the Cu film substrate, 50 substrates were polished, and the average value from the 10th sheet to the 50th sheet was obtained in consideration of the rise. Further, the thickness measurement was carried out by a DBS (Dual Beam Spectrometry) mode of an optical film thickness film measuring instrument (manufactured by KLA-Tencor Co., model "ASET-F5x").

[Table 2]

As shown in Table 2, in the examples, the number of microspheres 111 present per unit volume of the polishing layer 101 is 50,000 or more, for example, 71,250. On the other hand, in the comparative example, it was 32,750. Further, in the examples, the volume fraction of the microspheres 111 in the polishing layer 101 is 20% or less, for example, 18.1%. On the other hand, the comparative example was 22.9%. In the examples, the polishing rate of the insulating film (TEOS film) and the polishing rate of the metal film (Cu film) were increased as compared with the comparative example.
[Embodiment 2]

The difference in peel strength between the polishing layer 101 and the buffer layer 103 when the materials of the subsequent material layers 120 and 121 are changed will be described below. Here, the polishing layer 101 is a polyurethane resin. The average particle diameter of the microspheres 111 contained in the polishing layer 101 was 15 μm. The material of the buffer layer 103 is a non-woven material.

Table 3 shows the materials of the binder layers 120 and 120 of Examples A and B and Comparative Examples 1 and 2, and the subsequent methods. In the examples A and B and the comparative examples 1 and 2, the polishing pad 100B was produced under the same conditions except for the material of the adhesive layer and the subsequent method.

[table 3]

In each of Examples A and B and Comparative Examples 1 and 2, at least three or more polishing pads 100B were produced, and one of the three or more sheets was dried, and one of the sheets was immersed in water for 24 hours, and one of the sheets was immersed in 24 hours in 10% aqueous hydrogen peroxide (pH = 2.5). Thereafter, the peel strength between the polishing layer 101 and the buffer layer 103 in each of the polishing pads 100B was measured.

FIG. 5 is a graph showing the peel strength between the polishing layer 101 and the buffer layer 103.

As the adhesive, any of a hot melt adhesive (acrylic resin) and a pressure sensitive adhesive (acrylic resin or rubber resin) can be used. In the case of using a hot melt adhesive, the subsequent method is a hot melt type, and in the case of using a pressure sensitive type adhesive, the next method is pressure sensitive.

5, the examples A and B in which the adhesive layer 120 is a hot-melt adhesive are compared with the comparative examples 1 and 2 in which the adhesive layer 120 is a pressure-sensitive adhesive, and are immersed in a dry state or in water. In any of the 24 hours and the immersion in an aqueous hydrogen peroxide solution for 24 hours, the peel strength became large.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can of course be made. Each embodiment is not limited to an independent form, and may be combined as long as it is technically possible.

100A‧‧‧ polishing pad

100B‧‧‧ polishing pad

101‧‧‧Abrasive layer

101a‧‧‧ Grinding surface

101d‧‧‧1st main face

101u‧‧‧2nd main face

102‧‧‧Next layer (double-sided tape)

103‧‧‧buffer layer

110‧‧‧ polymer

110s‧‧‧ surface

111‧‧‧microspheres

111a‧‧‧ Shell

111b‧‧‧Internal space

111w‧‧‧ inner wall

120‧‧‧ adhesive layer

121‧‧‧ adhesive layer

125‧‧‧Substrate

200‧‧‧ manufacturing equipment

201‧‧‧1st storage tank

202‧‧‧2nd storage tank

203‧‧‧Stirring tank

204‧‧‧Mold

212‧‧‧ container

301‧‧‧Abrasive materials

401‧‧‧ pump

402‧‧‧ pump

410‧‧‧Switching valve

420‧‧‧Switching valve

501a‧‧‧Flow

501b‧‧‧Flow

501c‧‧‧flow path

502a‧‧‧Flow

502b‧‧‧Flow

502c‧‧‧Flow

503‧‧‧Flow

Fig. 1(a) is a schematic perspective view showing the polishing pad 100A of the first embodiment. Fig. (b) is a schematic cross-sectional view of the polishing pad 100A of the first embodiment. Figure (c) is a schematic cross-sectional view of the microsphere 111 of the first embodiment.

Fig. 2 is a schematic view showing a manufacturing apparatus 200 for manufacturing the polishing pad 100A of the present embodiment.

Fig. 3 is a schematic cross-sectional view showing a polishing pad 100B according to a second embodiment.

4(a) and 4(b) are schematic views showing the steps of bonding the polishing layer 101 and the buffer layer 103.

FIG. 5 is a graph showing the peel strength between the polishing layer 101 and the buffer layer 103.

Claims (10)

A polishing pad having: Substrate; and An abrasive layer disposed on the substrate and having Polyurethane resin, and a microsphere dispersed in the above-mentioned polyurethane resin and having an outer shell composed of a thermoplastic resin; The above microspheres have an average particle diameter of 20 μm or less. The polishing pad of claim 1, wherein the polishing layer has a density of 0.6 g/cm ³ or more and 0.9 g/cm ³ or less. A polishing pad according to claim 1 or 2, wherein The microsphere system heats the expandable spheres, and the average particle diameter before heating is 5 μm or more and 20 μm or less. A polishing pad according to claim 1 or 2, wherein The above microspheres dispersed in the above-mentioned polyurethane resin have an average particle diameter of 10 μm or more and 20 μm or less. A polishing pad according to claim 1 or 2, wherein The above-mentioned microspheres per unit volume of the polishing layer are 50,000 or more, and The volume fraction of the microspheres in the polishing layer is 20% or less. A polishing pad according to claim 1 or 2, wherein The polishing layer has a first main surface on the substrate side and a second main surface that forms a polishing surface on the opposite side of the substrate, and the first main surface is formed on the surface and the edge of the polyurethane resin. An inner wall surface of the microspheres on which the surface of the polyurethane resin is cut, and The polishing pad further includes a double-sided tape, and the double-sided tape is disposed between the substrate and the polishing layer, and is in contact with the surface of the polyurethane resin and the inner wall surface of the microsphere Hot melt adhesive layer. The polishing pad of claim 6, wherein The hot-melt adhesive layer is an acrylic resin. The polishing pad of claim 6, wherein The above substrate is a non-woven material, and The adhesive layer on the substrate side of the double-sided tape is a pressure-sensitive adhesive layer. A method of manufacturing a polishing pad, comprising the steps of: Preparing a liquid comprising microspheres and prepolymers having an average particle diameter of 5 μm or more and 20 μm or less and having an outer shell composed of a thermoplastic resin; Adding a hardener to the liquid to form an abrasive; and The polishing layer is formed by adjusting the average particle diameter so that the average particle diameter of the microspheres is one time or more and less than four times. A method of manufacturing a polishing pad according to claim 9, wherein In the step of preparing the liquid, the microspheres and the prepolymer are mixed at 80 ° C or lower, and In the step of forming the polishing layer, the temperature of the mold used for curing the polishing material is 100 ° C or less, and the time required for curing the polishing material is less than 150 seconds.