JP7176839B2 - polishing pad - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polishing pad for polishing an object to be polished.

A polishing pad is used for polishing optical materials, semiconductor devices, hard disk substrates, or the like. The polishing pad has a polishing layer made of synthetic resin, and voids are formed in the polishing layer. During polishing, the voids are opened on the surface of the polishing layer, and polishing of the object to be polished proceeds by retaining the polishing slurry in these openings.

The polishing pad includes a polishing layer, a substrate, and an adhesive layer provided between the substrate and the polishing layer. In such a laminated structure type polishing pad, when slurry permeates from the polishing layer or the side surface of the polishing pad to the adhesive layer or the cushion layer during polishing, separation may occur between the polishing layer and the cushion layer. .

On the other hand, there is a technique for preventing slurry from penetrating into the cushion layer by providing a layer called a waterproof layer between the polishing layer and the adhesive layer (see, for example, Patent Document 1). Alternatively, there is a technique in which the surface roughness of the back surface of the polishing layer is controlled to 1 μm or less to eliminate gaps at the interface between the polishing layer and the adhesive layer, thereby suppressing penetration of the slurry into the interface (see, for example, Patent Document 2). ).

JP 2009-095945 A Japanese Patent Application Laid-Open No. 2007-038372

However, providing a water stop layer in addition to the polishing layer, the base material and the adhesive layer, or performing surface treatment on the back surface of the polishing layer increases the number of parts and manufacturing man-hours, resulting in an increase in the manufacturing cost of the polishing pad. becomes higher.

In view of the circumstances as described above, it is an object of the present invention to provide a polishing pad that prevents a decrease in peel strength due to penetration of slurry during polishing while suppressing an increase in manufacturing cost.

To achieve the above object, a polishing pad according to one aspect of the present invention includes a substrate, a polishing layer, and a double-sided tape. The polishing layer is a layer containing a polyurethane resin and microspheres dispersed in the polyurethane resin and having an outer shell and an average particle diameter of 20 μm or less. The polishing layer has a first main surface on the substrate side and a second main surface forming a polishing surface on the side opposite to the substrate. The first main surface is composed of the surface of the polyurethane resin and the inner wall surfaces of the microspheres cut along the surface of the polyurethane resin. The double-sided tape includes 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.
With such a polishing pad, the pores in the polishing layer are closed cells composed of microspheres having outer shells, so that the slurry hardly permeates into the polishing layer. Furthermore, since the hot-melt adhesive layer of the double-sided tape is in contact with the surface of the polyurethane resin of the polishing layer and the inner wall surface of the microspheres, the substrate and the polishing layer are firmly adhered by an anchor effect.

In the above polishing pad, the microspheres may be heat-expandable spheres and have an average particle diameter of 5 μm or more and less than 20 μm before heating.
In such a polishing pad, heat-expandable spheres having an average particle diameter of 5 μm or more and less than 20 μm before heating are used as the microspheres, so that the inner wall surfaces of the microspheres, which are in contact with the hot-melt adhesive of the double-sided tape, are provided abundantly. The hot-melt adhesive adheres more firmly to the polishing layer.

In the above polishing pad, the microspheres dispersed in the polyurethane resin may have an average particle size of 10 to 20 μm.
With such a polishing pad, since the average particle diameter of the microspheres is 10 μm or more and 20 μm or less, it is possible to provide a large inner wall surface of the microspheres with which the hot melt adhesive of the double-sided tape is in contact. adheres more firmly to the polishing layer.

In the above polishing pad, the hot melt adhesive layer may be acrylic resin.
With such a polishing pad, since the hot-melt adhesive layer is made of acrylic resin, the hot-melt adhesive layer firmly adheres to the polishing layer.

In the polishing pad, the substrate may be a nonwoven fabric material, and the adhesive layer on the substrate side of the double-sided tape may be a pressure-sensitive adhesive layer.
With such a polishing pad, the substrate firmly adheres to the double-sided tape.

As described above, according to the present invention, it is possible to prevent a decrease in peel strength due to penetration of slurry during polishing while suppressing an increase in the manufacturing cost of the polishing pad.

FIG. (a) is a schematic perspective view showing the polishing pad 100 according to this embodiment. FIG. (b) is a schematic cross-sectional view of the polishing pad 100 according to this embodiment. 1 is a schematic diagram of a manufacturing apparatus 200 that manufactures a polishing pad 100 according to this embodiment; FIG. FIG. 4 is a schematic diagram showing a step of bonding the polishing layer 101 and the cushion layer 103 together; 4 is a graph showing the peel strength between the polishing layer 101 and the cushion layer 103. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. XYZ axis coordinates may be introduced in each drawing.

[Overview of Polishing Pad]
FIG. 1(a) is a schematic perspective view showing a polishing pad 100 according to this embodiment.

A polishing pad 100 comprises a polishing layer 101 , a double-sided tape 102 and a cushion layer 103 .

The polishing layer 101 is a layer that contacts and polishes an object to be polished. Hereinafter, the surface of the polishing layer 101 is referred to as a polishing surface 101a. Grooves and holes (not shown) may be formed in the polishing surface 101a to improve the flow of the slurry liquid.

The double-sided tape 102 is a layer that adheres the polishing layer 101 and the cushion layer 103 together.

The cushion layer 103 is a base material of the polishing pad 100, and is a layer that makes contact of the polishing layer 101 with the object to be polished more uniform. The cushion layer 103 can be made of a flexible material such as a nonwoven fabric material or a synthetic resin.

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

The polishing pad 100 is rotationally driven while being pressed against the object to be polished by the polishing device, and polishes the object to be polished. At that time, a slurry liquid is supplied between the polishing pad 100 and the object to be polished. The slurry liquid is supplied to and discharged from the polishing surface 101a through the grooves or holes.

[Structure of Polishing Layer]
FIG. 1(b) is a schematic cross-sectional view of the polishing pad 100 according to this embodiment. FIG. 1B shows 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 together.

In polishing pad 100 , polishing layer 101 includes polymer 110 and microspheres 111 . The abrasive layer 101 is provided on the cushion layer 103 via the double-sided tape 102 . In the polishing layer 101, the surface on the cushion layer 103 side is referred to as a first main surface 101d, and the surface opposite to the cushion layer 103 and constituting the polishing surface 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 the surface 110s of the polymer 110 and the inner wall surface 111w of the microsphere 111. As shown in FIG. Note that the microsphere in this embodiment is not limited to a sphere whose outer peripheral surface is a true spherical surface, and includes a sphere whose outer peripheral surface has a slightly distorted spherical surface.

Polymer 110 is the main constituent material of the abrasive material. Polymer 110 can be a polymer produced by a polymerization reaction of a prepolymer and a curing agent. Examples of such polymers include polyurethane resins and the like. Polyurethane is a preferred polymer 110 because it is readily available, easy to process, and has suitable abrasive properties.

The prepolymer can be a compound having an isocyanate group terminal (hereinafter referred to as an isocyanate compound), and is a compound obtained by reacting a polyisocyanate compound and a polyol compound under commonly used conditions. It contains a group in the molecule. Further, other components may be contained in the polyurethane bond-containing isocyanate compound within a range that does not impair the effects of the present invention.

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

In addition, polyisocyanate compounds include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1 ,4-diisocyanate, 4,4′-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate (HDI), isophorone diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1, 2-diisocyanate, cyclohexylene-1,4-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate and ethylidine diisothiocyanate is mentioned. These 1 type(s) or 2 or more types can be used.

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

In addition, polyol compounds include diol compounds such as ethylene glycol and butylene glycol, triol compounds, etc.; polyether polyol compounds such as PTMG; reaction products of ethylene glycol and adipic acid; and reaction products of butylene glycol and adipic acid. and polyester polyol compounds; polycarbonate polyol compounds, polycaprolactone polyol compounds, and the like. These 1 type(s) or 2 or more types can be used.

A polyamine-based curing agent can be used as the curing agent. Polyamine-based curing agents are substances having two or more amino groups, and include alkylenediamines such as ethylenediamine, propylenediamine and hexamethylenediamine; Diamine; diamine having an aromatic ring such as MOCA (3,3-dichloro-4,4-diaminodiphenylmethane); 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2 - diamines having a hydroxyl group such as hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, especially hydroxyalkylalkylenediamine; Tri-functional triamine compounds and tetra- or higher-functional polyamine compounds can also be used.

A polyol-based curing agent can also be used as the curing agent. A polyol-based curing agent is a substance having two or more hydroxyl groups and can be, for example, ethylene glycol or polyether polyols.

In addition, as polyol-based curing agents, low-molecular-weight polyol compounds such as butylene glycol and hexanediol, as well as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol (PTMG), reaction products of bisphenol A and propylene oxide Polyether polyol compounds such as polyether polyol compounds, reaction products of ethylene glycol and adipic acid, polyester polyol compounds such as reaction products of butylene glycol and adipic acid, polycarbonate polyol compounds and high molecular weight polyol compounds such as polycaprolactone polyol compounds .

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

Here, each component is added so that the R value, which is the equivalent ratio of the amino group or hydroxyl active hydrogen group present in the curing agent to the isocyanate group present at the end of the prepolymer, is 0.7 to 1.2. Mix. The R value is preferably 0.7 to 1.2, more preferably 0.8 to 1, still more preferably 0.85 to 0.95. By setting the R value to 1 or less, excess isocyanate groups are used for the crosslinking reaction described below.

The double-sided tape 102 has a base material 125 and adhesive layers 120 and 121 provided on both sides of the base material 125 . Adhesive layer 120 is provided between substrate 125 and polishing layer 101 . The adhesive layer 121 is provided between the base material 125 and the cushion layer 103 . Adhesive layer 120 is a hot-melt adhesive layer, and adhesive layer 121 may be a hot-melt adhesive layer or another type (eg, pressure-sensitive) adhesive layer. When a non-woven fabric material is used as the cushion layer 103, if the adhesive layer 121 is a hot-melt adhesive layer, the adhesive strength will be extremely reduced when the slurry liquid permeates the cushion layer. is preferred.

The hot-melt adhesive layer contains thermoplastic resins such as acrylic resins, ethylene vinyl acetate resins, olefin resins, synthetic rubber resins, polyamide resins, and polyester resins. The component of the adhesive layer 120 is not limited to one component, and may be of a mixed type containing two or more liquids. The adhesive layer 121 on the cushion layer 103 side is not limited to a hot-melt adhesive layer. A pressure-sensitive adhesive layer such as a polymer-based adhesive may also be used.

The base material 125 is the base of the double-sided tape 102 . The base material 125 is made of, for example, polyimide-based resin, polyester-based resin, polyurethane-based resin, polyethylene-based resin, polypropylene-based resin, cellulose-based resin, polyvinyl chloride-based resin, polyvinylidene chloride-based resin, polyvinyl alcohol-based resin, ethylene- It includes vinyl acetate copolymer-based resins, polystyrene-based resins, polycarbonate-based resins, acrylic-based resins, laminate resins of two or more of these, and the like.

Microspheres 111 are dispersed in polymer 110 . A microsphere 111 is a spherical object having an outer shell. The microspheres 111 are hemispherical on the first major surface 101d and the second major surface 101u (polishing surface 101a) of the polishing layer 101, and the inner walls thereof are exposed. The hemispherical microspheres 111 are cut along the surface of the polymer 110 together with the polymer 110 after the block-shaped polishing layer 101 is formed.

In polishing pad 100 , adhesive layer 120 is in close contact with base material 125 and in close contact with first major surface 101 d of polishing layer 101 . For example, adhesive layer 120 is in contact with surface 110 s of polymer 110 and inner wall surface 111 w of microsphere 111 . That is, the adhesive layer 120 is not only in contact with the surface 110s of the polymer 110 on the first main surface 101d, but also penetrates inside the microspheres 111. As shown in FIG.

The microsphere 111 has a spherical outer shell 111a made of thermoplastic resin and an inner space 111b surrounded by the outer shell 111a. Vinylidene chloride and acrylonitrile, for example, are used as the thermoplastic resin. The microspheres 111 are low-boiling hydrocarbons wrapped in thermoplastic resin shells. The microspheres 111 are heat-expandable spheres, and heat-expandable spheres having an average particle diameter of 5 μm or more and 20 μm or less before heating are used.

Expansion of the microspheres 111 is suppressed by adjusting the reaction conditions in the polymerization reaction of the prepolymer. For example, the reaction heat generated by the polymerization reaction can be rapidly cooled, or the polymerization reaction of the prepolymer can be rapidly accelerated so that the expansion is forcibly suppressed by the polymer present around the microspheres 111 . Alternatively, the microspheres 111 may slightly expand due to the heat of formation accompanying the polyurethane formation reaction.

However, the average particle size of the microspheres 111 contained in the polishing layer 101 is adjusted to 10 μm or more and 20 μm or less. For example, the average particle size of microspheres 111 dispersed in polymer 110 is 15 μm. The particle size of the microspheres 111 is calculated from, for example, a laser diffraction particle size distribution measuring device, X-ray CT (Computed Tomography), electron microscope image, and the like.

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

A commercially available product can also be used for the microsphere 111 . For example, the Matsumoto Microsphere series (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) and the Expancel series (manufactured by AkzoNobel) can be used as the microspheres 111 .

In this embodiment, two or more types of microspheres 111 having different diameters may be used. The content of the microspheres 111 in the abrasive 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 15% by volume or more. 30% by volume or less is more preferable. The microspheres 111 are exposed on the polishing surface 101a when the polishing layer 101 is worn by polishing, and affect the polishing characteristics of the polishing surface 101a.

[Method for producing polishing pad]

FIG. 2 is a schematic diagram of a manufacturing apparatus 200 that manufactures the polishing pad 100 according to this embodiment.

The manufacturing apparatus 200 includes a first storage tank 201, a second storage tank 202, a stirring tank 203 (mixing container), a mold 204, a container 212, a pump 401, a pump 402, a switching valve 410, a switching valve 420, a channel 501a, a channel 501b. , a channel 501c, a channel 502a, a channel 502b, a channel 502c and a channel 503. FIG. The manufacturing apparatus 200 is an example, and is not limited to this example.

The first reservoir 201 can contain contents (liquid) including microspheres 111 and prepolymer. The microspheres 111 are stored in advance in a container 212 provided above the first reservoir 201 . The microspheres 111 are put into the first storage tank 201 from the container 212 via the channel 503 . By introducing the microspheres 111 from the container 212 into the first storage tank 201 via the channel 503, scattering of the microspheres 111 to the outside of the first storage tank 201 is suppressed. A second reservoir 202 can contain a curing agent that cures the prepolymer. Agitation tank 203 mixes a liquid containing microspheres 111 and prepolymer with a curing agent to form 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. Furthermore, the polishing characteristics of the polishing pad 100 can be adjusted by adjusting the amount of the microspheres 111 charged.

A pump 401 can supply a liquid containing microspheres 111 and prepolymer from the first reservoir 201 to the agitation reservoir 203 . Pump 401 is provided in the middle of channel 501a. When the flow path 501a and the flow path 501b are communicated by the switching valve 410 and the pump 401 is operated, the liquid containing the microspheres 111 and the prepolymer flows from the first storage tank 201 to the stirring tank 203 through the flow paths 501a and 501b. supplied to

A pump 402 can supply hardener from the second reservoir 202 to the agitation tank 203 . Pump 402 is provided in the middle of channel 502a. When the channel 502a and the channel 502b are connected by the switching valve 420 and the pump 402 is operated, the curing agent is supplied from the second storage tank 202 to the stirring tank 203 through the channels 502a and 502b.

Further, in the manufacturing apparatus 200, the channel 501a and the channel 501c are communicated by the switching valve 410, and when the pump 401 is operated, the liquid containing the microspheres 111 and the prepolymer flows through the channels 501a and 501c. It circulates between the first storage tank 201 and the pump 401 . Further, when the channel 502a and the channel 502c are connected by the switching valve 420 and the pump 402 is operated, the curing agent circulates between the second storage tank 202 and the pump 402 via the channels 502a and 502c. The mold 204 receives the abrasive material 301 from the agitation tank 203 and forms the abrasive 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. As shown in FIG. The average particle diameter of the microspheres 111 before being put into the first storage tank 201 is 5 μm or more and less than 20 μm, more preferably 5 μm or more and 10 μm or less. The prepolymer can be an isocyanate compound. A curing agent is put 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 to a predetermined temperature. However, expansion of the microspheres 111 is suppressed as much as possible.

Next, the contents in the first storage tank 201 (hereinafter referred to as the first solution) are delivered from the first storage tank 201 to the stirring tank 203 through the channel 501a, the pump 401, the switching valve 410 and the channel 501b. From the second storage tank 202, the contents of the second storage tank 202 (hereinafter referred to as second solution) pass through the channel 502a, the pump 402, the switching valve 420 and the channel 502b, and are delivered to the stirring tank 203. As a result, a fluid polishing material 301 in which the first solution and the second solution are mixed in the stirring tank 203 is formed.

Abrasive material 301 is then poured into mold 204 for casting. In the abrasive material 301 in the mold 204, the prepolymer and the curing agent are polymerized. Here, as the polymerization reaction progresses, the mixture is cured to form a block-like substance made of the polymer. At this time, the reaction conditions are controlled to adjust the average particle size of the microspheres 111 after the polymerization reaction while the polishing material 301 is cured.

For example, in the present embodiment, the pot life (the time it takes for the polymerization reaction to progress and harden) is less than 150 seconds and the polymerization reaction of the prepolymer is rapidly accelerated, so that the microspheres 111 are polymerized faster than the expansion speed of the microspheres 111. The viscosity of the mixture is increased by accelerating the reaction, and the average particle size of the microspheres 111 after the polymerization reaction is at least 1 times the average particle size of the microspheres 111 before the microspheres 111 are introduced into the first storage tank 201. The polishing layer 101 is formed so as to be less than twice as large. However, the average particle size of the microspheres 111 is adjusted to 20 μm or less. In consideration of controlling the expansion of the microspheres 111, the pot life is preferably 60 seconds or more and 150 seconds or less.

Note that the microspheres 111 are fine particles, and when the microspheres 111 are put into the first storage tank 201 from above the first storage tank 201 , they rise up in the first storage tank 201 and adhere to the inner wall of the first storage tank 201 . may adhere to As a result, the microspheres 111 may not be efficiently dispersed in the prepolymer. Therefore, the microspheres 111 may be introduced from the lower side of the first reservoir 201 through the channel. As a result, the microspheres 111 are directly mixed with the prepolymer accumulated at the bottom of the first storage tank 201 immediately after being put into the first storage tank 201 .

Microspheres 111 may be introduced into second reservoir 202 . In this case as well, the microspheres 111 can be introduced into the second storage tank 202 using the channel from the lower side of the second storage tank 202 in the same manner as the method of charging the first storage tank 201 .

Thereafter, by slicing the block-shaped polishing layer 101, a sheet-shaped polishing layer 101 is obtained. At this time, the microspheres 111 exposed on the main surfaces 101u and 101d of the polishing layer 101 are cut, and the inner wall surfaces 111w of the microspheres 111 are exposed on the main surfaces 101u and 101d of the polishing layer 101 . The inner wall surfaces 111w are exposed from the cut microspheres 111 by evaporating or releasing low boiling point hydrocarbons into the air.

3(a) and 3(b) are schematic diagrams showing the process of bonding the polishing layer 101 and the cushion layer 103 together.

As shown in FIG. 3A, after preparing the abrasive layer 101, the double-sided tape 102, and the cushion layer 103 sliced into sheets, the abrasive layer 101 and the cushion layer 103 are opposed to each other. A double-faced tape 102 is interposed between the cushion layer 103 and the cushion layer 103 . 3A and 3B, the adhesive layer 120 is assumed to be a hot-melt adhesive layer, and the adhesive layer 121 is assumed to be a pressure-sensitive adhesive layer.

First, the double-sided tape 102 and the cushion layer 103 are pressurized and adhered, and then the adhesive layer 120 of the double-sided tape 102 and the polishing layer 101 are heated and adhered to form a laminate (hot-melt adhesion). .

At this time, the fluidity and adhesiveness of the adhesive layer 120 are increased by heating, so that the adhesive layer 120 adheres to the polishing layer 101 and the adhesive layer 121 adheres to the cushion layer 103 . At this time, on the first main surface 101d, the adhesive layer 120 contacts the surface 110s of the polymer 110, enters the microspheres 111, and contacts the inner wall surfaces 111w of the microspheres 111 (see FIG. 1B).

The heating temperature is set to, for example, 80° C. or higher and 110° C. or lower. During heating, pressure may be applied from the polishing layer 101 to the double-sided tape 102 and from the cushion layer 103 to the double-sided tape 102 as necessary. At this time, since the periphery of the microsphere 111 is surrounded by the polymer 110, thermal expansion or deformation hardly occurs.

After the polishing layer 101 and the cushion layer 103 are adhered with the double-sided tape 102, the laminate is cut into a desired shape (for example, disc shape) to form a polishing pad 100 as shown in FIG. 1(a). be done.

With such a polishing pad 100, since the voids in the polishing layer 101 are closed cells composed of the microspheres 111 having the outer shells 111a, the slurry penetrates into the polishing layer 101 through the microspheres 111. Can not. As a result, the slurry does not penetrate from the second main surface 101u of the polishing layer 101 to the first main surface 101d. That is, the slurry does not reach the double-sided tape 102 from the second main surface 101u of the polishing layer 101 .

Further, with the polishing pad 100 , more inner wall surfaces of the microspheres 111 with which the hot-melt adhesive of the double-sided tape 102 contacts can be provided, so that the double-sided tape 102 adheres more firmly 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 anchor effect works between the polishing layer 101 and the double-sided tape 102. The polishing layer 101 and the double-sided tape 102 are firmly adhered to each other. This makes it difficult for the polishing layer 101 to peel off from the double-sided tape 102 .

In particular, in the polishing layer 101 according to this embodiment, the adhesive layer 120 penetrates into the fine microspheres 111 having an average particle size of 20 μm or less (eg, 15 μm) on the first main surface 101d. This further promotes the anchor effect and increases the peel strength between the polishing layer and the adhesive layer.

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 surfaces 111w of the microspheres 111, the surface area of the first main surface 101d is only the surface 110s of the polymer 110. It is larger than when it is composed of As a result, the contact area of the adhesive layer 120 with the first main surface 101d is increased, and the adhesion of the adhesive layer 120 to the polishing layer 101 is improved.

In addition, in this embodiment, it is not necessary to provide a waterproof layer between the polishing layer 101 and the double-sided tape 102 . As a result, an increase in manufacturing cost of the polishing pad can be suppressed. Further, even if a waterproof layer is provided between the polishing layer 101 and the double-sided tape 102, if the voids in the polishing layer are not composed of the microspheres 111, the slurry will flow through the polishing layer and both sides of the polishing layer. There is a possibility that it will permeate between the tape and the adhesion between the abrasive layer and the waterproof layer.

Moreover, in the present embodiment, it is not necessary to adjust the surface roughness (Ra) of the first main surface 101d of the polishing layer 101 to 1 μm or less. As a result, an increase in manufacturing cost of the polishing pad can be suppressed. In the present embodiment, since the adhesive layer 120 is firmly adhered to the polishing layer 101 by the anchor effect, there is almost no gap at the interface between the polishing layer 101 and the double-sided tape 102, so that slurry does not enter the interface. Intrusion can be effectively prevented.

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

In addition, in the present embodiment, since the average particle size of the microspheres 111 contained in the first solution is 5 μm or more and less than 20 μm, the first solution flows through the channel 501a, the pump 401, the switching valve 410, and the channel 501b. The fluidity of the first solution during passage is improved. This suppresses clogging of the first solution in each of the channel 501a, the pump 401, the switching valve 410, and the channel 501b. As a result, foreign matter is less likely to remain in the polishing material 301 .

Differences in peel strength between the abrasive layer 101 and the cushion layer 103 when the materials of the adhesive layers 120 and 121 are changed are shown below. Here, the polishing layer 101 is polyurethane resin. The average particle diameter of the microspheres 111 contained in the polishing layer 101 is 15 μm. The material of the cushion layer 103 is a non-woven material.

Table 1 shows the materials of the adhesive layers 120 and 120 in Examples 1 and 2 and Comparative Examples 1 and 2 and their bonding methods. The polishing pad 100 was produced under the same conditions as in Examples 1 and 2 and Comparative Examples 1 and 2 except for the material of the adhesive layer and the bonding method.

In each of Examples 1 and 2 and Comparative Examples 1 and 2, at least three polishing pads 100 were prepared. % hydrogen peroxide aqueous solution (pH=2.5) for 24 hours. After that, the peel strength between the polishing layer 101 and the cushion layer 103 in each polishing pad 100 was measured.

FIG. 4 is a graph showing the peel strength between the abrasive layer 101 and the cushion layer 103. As shown in FIG.

As the adhesive, either a hot-melt adhesive (acrylic resin) or a pressure-sensitive adhesive (acrylic resin, rubber resin) is used. When a hot-melt adhesive is used, the bonding method is hot-melt, and when a pressure-sensitive adhesive is used, it is pressure-sensitive.

As is clear from FIG. 4, in Examples 1 and 2 in which the adhesive layer 120 is a hot-melt adhesive, compared to Comparative Examples 1 and 2 in which the adhesive layer 120 is a pressure-sensitive adhesive, the dry state and water It was found that the peel strength increased in both cases of immersion for 24 hours and immersion in an aqueous hydrogen peroxide solution for 24 hours.

Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments and can be modified in various ways. Each embodiment is not limited to an independent form, and can be combined as much as technically possible.

DESCRIPTION OF SYMBOLS 100... Polishing pad 101... Polishing layer 101a... Polishing surface 101d... 1st main surface 101u... 2nd main surface 102... Double-sided tape 103... Cushion layer 110... Polymer 110s... Surface 111... Microsphere 111a... Outer shell 111b... Internal space DESCRIPTION OF SYMBOLS 111w... Inner wall surface 120, 121... Adhesive bond layer 125... Base material 200... Manufacturing apparatus 201... 1st storage tank 202... 2nd storage tank 203... Stirring tank 204... Mold 212... Container 301... Polishing material 401, 402... Pump 410, 420... Switching valve 501a, 501b, 501c, 502a, 502b, 502c, 503... Flow path

Claims (4)

a substrate;
A polyurethane resin formed by a polymerization reaction of a prepolymer having a pot life of less than 150 seconds and a curing agent, an outer shell dispersed in the polyurethane resin and softer than the polyurethane resin, and an inner space surrounded by the outer shell. and microspheres having an average particle diameter of 20 μm or less, the layer having a first main surface on the substrate side and a second main surface constituting a polishing surface on the side opposite to the substrate. a polishing layer in which the first main surface is composed of the surface of the polyurethane resin and inner wall surfaces of the microspheres cut along the surface of the polyurethane resin;
a double-sided tape provided between the base material and the polishing layer and including a hot-melt adhesive layer in contact with the surface of the polyurethane resin and the inner wall surface of the microspheres ,
The microspheres are heat-expandable spheres, and have an average particle diameter of 5 μm or more and less than 20 μm before heating.
polishing pad. The polishing pad according to claim 1 ,
The polishing pad, wherein the microspheres dispersed in the polyurethane resin have an average particle size of 10 μm or more and 20 μm or less. The polishing pad according to claim 1 or 2 ,
A polishing pad, wherein the hot-melt adhesive layer is an acrylic resin. The polishing pad according to any one of claims 1 to 3 ,
the substrate is a nonwoven material,
A polishing pad, wherein the adhesive layer on the substrate side of the double-sided tape is a pressure-sensitive adhesive layer.

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