JP7193221B2 - Polishing pad, method for producing same, and method for producing abrasive product - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polishing pad, a method for manufacturing the same, and a method for manufacturing a polished article.

In recent years, materials such as silicon carbide (SiC), gallium nitride (GaN), diamond, sapphire (Al ₂ O ₃ ), and aluminum nitride (AlN), which are wide bandgap semiconductors, have attracted attention as materials for next-generation power semiconductor devices. there is For example, silicon carbide (SiC) has excellent physical properties such as a bandgap three times that of Si semiconductors and a dielectric breakdown field strength approximately seven times that of Si semiconductors. It is superior in that it is highly efficient, compact, and has a high energy-saving effect. In addition, sapphire wafers are used for electronic devices with optical elements, such as high-performance overheads, due to their chemical stability, optical properties (transparency), mechanical strength, and thermal properties (good thermal conductivity). Its importance as a component for projectors is increasing. Toward the full-scale popularization of these next-generation power devices, substrate diameters are being increased and mass production is being promoted, and along with this, the importance of substrate processing technology is also increasing. In such a substrate processing process, similarly to Si, a columnar single crystal (ingot) used for a wafer is first sliced into discs. Next, the surface of the sliced disk-shaped single crystal is flattened. First, lapping is performed using a lapping platen in order to roughly flatten the surface. After that, polishing is performed in order to further improve the flatness of the surface of the disk-shaped single crystal and to remove fine scratches on the surface to make it a mirror finish.

In a general lapping process, polishing is performed using a metal surface plate in the presence of slurry containing diamond abrasive grains. As a result, diamond abrasive grains, which are loose abrasive grains, are embedded in the surface of the metal-based surface plate, and lapping can be performed. In particular, as a lapping process for high-hardness materials such as SiC, which is much harder than Si, a metallic surface plate such as copper and tin is used, and the surface plate and diamond abrasive grains, which are free abrasive grains, are used. (hereinafter also referred to as “diamond lapping”) is known (see, for example, Patent Document 1). Further, in the polishing step, which is a step after lapping, a plurality of polishing structures in which abrasive particles (fixed abrasive grains) having a primary particle diameter of less than 3 μm are dispersed in a saturated copolyester resin are formed. A method of polishing using a sheet without using loose abrasive grains is known (see, for example, Patent Document 2).

JP-A-2007-61961 JP 2009-72832 A

However, since the metal surface plate as described in Patent Document 1 is heavy, it is difficult to handle, and maintenance after use, such as cleaning the surface of the surface plate in which diamond abrasive grains, which are free abrasive grains, are embedded, requires labor. There is a problem.

The polishing sheet described in Patent Document 2 is used for general polishing of glass, ceramics, plastics, metals, and the like. If such a polishing sheet used for general polishing is used for processing SiC or the like, there is a problem that the polishing rate is low and it is not practical. In particular, in the polishing sheet described in Patent Document 2, only the abrasive particles exposed on the surface of the polishing structure function as fixed abrasive grains, and the abrasive particles embedded in the polishing structure do not function as abrasive grains. There is room for further improvement in the polishing rate.

In addition to SiC, sapphire also has a modified Mohs hardness second only to that of diamond and SiC, is highly resistant to chemicals, and is extremely difficult to process. Therefore, in addition to general Si semiconductor wafers, materials expected as next-generation power semiconductor device materials, particularly difficult-to-process materials with high hardness, excellent handling and excellent polishing rate. A pad is desired.

The present invention has been made in view of the above circumstances, and provides a polishing pad that is excellent in handleability and maintainability, and is particularly excellent in polishing rate in polishing difficult-to-cut materials, a method for manufacturing the same, and a polishing pad using the same. It is an object of the present invention to provide a method for manufacturing a polished product.

The present inventors have made intensive studies to solve the above problems. As a result, the present inventors have found that a polishing pad having a polishing surface with a predetermined concave-convex pattern can solve the above problems, and have completed the present invention.

That is, the present invention is as follows.
[1]
comprising a base material and a resin part (excluding a structure comprising a fibrous substance and an adhesive) that serves as a convex part arranged separately on the base material,
The surface of the convex portion has a polishing surface for polishing an object to be polished,
The number of protrusions is 5 to 80 per unit area (1 cm ² ) of the surface,
an effective polishing area of the polishing surface is 0.15 to 0.70 cm ² per unit area (1 cm ² ) of the surface;
The polishing surface does not substantially contain fixed abrasive grains,
Shore D hardness of the resin portion is 60 to 95 ,
wherein the substrate comprises a polyester-based film ;
polishing pad.
[2]
The convex portion has a dot shape,
The polishing pad according to [1].
[3]
The area A of the dot-shaped protrusions is 0.15 to 0.70 cm ² per unit area (1 cm ² ) of the surface.
The polishing pad according to [2].
[4]
The resin part contains polyurethane acrylate,
[1] The polishing pad according to any one of [3] .
[5]
An adhesive layer is further provided on the side opposite to the resin portion of the base material,
[1] The polishing pad according to any one of [4] .
[6]
an application step of applying a curable composition (excluding one containing a fibrous substance and an adhesive) onto a substrate;
a curing step of curing the adhered curable composition to obtain a cured layer;
The cured layer constitutes an uneven pattern alone or together with the base material,
The surface of the uneven pattern has a polishing surface for polishing an object to be polished,
an effective polishing area of the polishing surface is 0.15 to 0.70 cm ² per unit area (1 cm ² ) of the surface;
The polishing surface does not substantially contain fixed abrasive grains,
The Shore D hardness of the resin portion constituted by the cured layer is 60 to 95.
A method for manufacturing a polishing pad.
[7]
A polishing step of polishing an object to be polished using the polishing pad according to any one of [1] to [5] in the presence of abrasive grains,
A method for producing an abrasive product.

INDUSTRIAL APPLICABILITY According to the present invention, there are provided a polishing pad which is excellent in handleability and maintainability, and particularly excellent in polishing rate in polishing difficult-to-cut materials, a method for producing the same, and a method for producing a polished product using the polishing pad. can do.

It is a schematic perspective view showing an example of the polishing pad of this embodiment. 4 is a schematic perspective view showing another example of the polishing pad of the present embodiment; FIG. It is a schematic diagram showing a method of measuring an effective polishing area. It is a schematic diagram showing a method for measuring the effective polishing area using a coloring liquid. FIG. 4 is a top view showing the pressure-sensitive paper 4 to which the coloring liquid is transferred in the method of measuring the effective polishing area using the coloring liquid. It is a schematic diagram which shows an example of the uneven|corrugated pattern of this embodiment. FIG. 4 is a cross-sectional view showing an example of the uneven pattern of the present embodiment; 4 is a photograph of the polishing surfaces of the polishing pads of Examples 1 and 5. FIG.

EMBODIMENT OF THE INVENTION Hereinafter, the form (only henceforth "this embodiment") for implementing this invention is demonstrated in detail, referring drawings as needed. In the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to the illustrated ratios.

[Polishing pad]
The polishing pad of the present embodiment comprises a base material and a resin part disposed on the base material, the resin part constitutes a concavo-convex pattern alone or together with the base material, and the surface of the concavo-convex pattern is , a polishing surface for polishing an object to be polished, the concave-convex pattern having 5 to 80 convex portions or concave portions per unit area (1 cm ² ) of the surface, and effective polishing on the polishing surface; The surface area is 0.15 to 0.7 cm ² per unit area (1 cm ² ) of the surface, and the polishing surface does not substantially contain fixed abrasive grains.

FIG. 1 shows a schematic perspective view showing an example of the polishing pad of this embodiment. As shown in FIG. 1, this polishing pad 10 includes a substrate 12 and a resin portion 11 disposed on the substrate 12. The resin portion 11 forms an uneven pattern together with the substrate 12. . The concave-convex pattern is a pattern (positive pattern) in which a plurality of semispherical dots formed by the resin portion 11 are arranged on the surface of the base material 12 . Moreover, FIG. 2 shows a schematic perspective view showing another example of the polishing pad of the present embodiment. As shown in FIG. 2, this polishing pad 20 includes a substrate 22 and a resin portion 21 disposed on the substrate 22. The resin portion 21 forms an uneven pattern together with the substrate 22. . In this polishing pad 20, a sheet-like resin portion 21 is arranged on the surface of a substrate 22, and the resin portion 21 is punched out in dots to form an uneven pattern (negative pattern). Moreover, the polishing pad of the present embodiment may have adhesive layers 13 and 23 as necessary.

Since the polishing pad of the present embodiment has a base material and a resin part arranged on the base material, it is lighter than a metal-based surface plate, and can be disposed after a predetermined number of times of polishing. and excellent maintainability. In addition, this polishing pad has an uneven pattern, and has an effective polishing area within the above numerical range on the polishing surface of the uneven pattern surface, so that it has an excellent polishing rate and exhibits a polishing rate comparable to that of a metal surface plate. can do. This is because (1) during polishing, free abrasive grains such as diamond abrasive grains are interposed between the object to be polished and the convex portions that are in close contact with the object to be polished, so that the convex portions and the free abrasive grains are effectively separated. (2) the provision of recesses increases the pressing force per unit area on the surface in close contact with the object to be polished; and (3) the above numerical range. It is considered that the above (1) and (2) are well balanced by having an effective polishing area within. However, the factor is not limited to this. Further, when the uneven pattern is regular, more uniform polishing becomes possible, and polishing with excellent surface quality can be achieved.

〔Base material〕
The base material is not particularly limited, but for example, polyester films such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate; polyolefin films such as polyethylene (PE) film, polypropylene (PP) film, and ethylene-propylene copolymer film; Film; polyether ether ketone (PEEK) film, polyphenylene sulfide (PPS) film. As the base material, any material can be used as long as the resin to be described later can be printed on the upper surface, but a polyester film is preferable from the viewpoint of chemical resistance, heat resistance, economy, and the like.

[Resin part]
The resin part is arranged on the base material and constitutes the concave-convex pattern alone or together with the base material. The surface of the resin portion on the side opposite to the substrate serves as a polishing surface for polishing the object to be polished. In addition, in the polishing pad of this embodiment, the polishing surface does not substantially contain fixed abrasive grains. The phrase "substantially free of fixed abrasive grains" means that no abrasive grains appear on the polishing surface, which is the surface of the resin portion. Since the polishing surface does not substantially contain abrasive grains, it is possible to increase the area of the polishing surface on which free abrasive grains remain.

The uneven pattern has 5 to 80 protrusions or recesses per unit area (1 cm ² ) of the surface, preferably 15 to 75, more preferably 30 to 70. When the number of uneven patterns per unit area is 5 or more, the ability to supply and discharge slurry containing free abrasive grains is excellent, and the polishing rate is improved. As the number of uneven patterns per unit area is increased, the polishing rate is improved. If the number per unit area is 80 or more, the height of each concave-convex pattern becomes low, and there is a possibility that the durability during polishing may be lowered. The number of uneven patterns per unit area can be calculated by visually confirming the number of uneven patterns in a predetermined area, for example, 4 cm ² (2 cm square), and converting it into the number per unit area.

The effective polishing area of the polishing surface is 0.15 to 0.7 cm ² , preferably 0.2 to 0.65 cm ² , more preferably 0.25 to 0.25 cm 2 per unit area (1 cm ² ) of the surface. .6 cm ² . When the effective polishing area per unit area is 0.15 cm ² or more, the area that can contribute to polishing is increased, and the polishing rate is further improved. Although the effective polishing area per unit area is preferably as large as possible, if the number of uneven patterns per unit area is small, the supply and discharge of the slurry containing loose abrasive grains becomes insufficient. ^When the number of uneven patterns per unit area is large, it is difficult to form a printed pattern as described above.

Here, the term "effective polishing area on the polishing surface" refers to the area of the protrusions contributing to polishing in the uneven pattern per unit area (1 cm ² ). FIG. 3 shows a method for measuring the effective polishing area. First, the polishing surface of the polishing pad 10 (the surface of the resin portion 11) and the flat surface of the pressure-sensitive paper 4 for measuring the effective polishing area (4LW for low pressure, two-sheet type manufactured by Fuji Film) are superposed so as to be in direct contact. Then, they are pressed by a roller or the like having a sufficiently large area against the uneven pattern so that a load is not applied to one point. At that time, the area of the polishing surface 5 in contact with the pressure-sensitive paper 4 (coloring area) is measured, and this is defined as the area of the protrusions contributing to polishing in the uneven pattern. Then, by photographing the coloring area of the pressure-sensitive paper 4 with a microscope and performing binarization processing, the area of the polishing surface 5 in contact (the area 6 transferred onto the pressure-sensitive paper 4) per unit area (1 cm ² ) (Colored portion of pressure-sensitive paper)) is calculated and taken as the effective polishing area on the polishing surface per unit area (1 cm ² ). The binarization processing can be calculated using general binarization processing software.

The area of the abrasive surface 5 in contact can also be derived, for example, using a pressure-sensitive paper coloring liquid. FIG. 4 shows the method of measuring the effective polishing area when using the coloring liquid for the pressure-sensitive paper. Before the polishing pad 10 and the pressure-sensitive paper 4 are placed on top of each other, the polishing surface of the polishing pad 10 (the surface of the resin portion 11) is manually coated with an appropriate amount of coloring liquid of the pressure-sensitive paper for measuring the area, and after applying pressure, By separating the polishing pad 10 and the pressure-sensitive paper 4 and measuring the area 6 transferred onto the pressure-sensitive paper 4 (the colored portion of the pressure-sensitive paper), the area of the polishing surface 5 in contact with the pressure-sensitive paper 4 can be derived. can. FIG. 5 is a top view showing the transferred pressure-sensitive paper 4 in the case of a pattern having dot-like convex portions, where the transferred area 6 is the area of the contact polishing surface 5 (that is, the effective polishing area). be the same.

The concave-convex pattern is not particularly limited as long as it is a pattern having a portion (convex portion) that contacts the object to be polished and a portion (concave portion) that does not contact the object to be polished. For example, as shown in FIG. A positive pattern (a pattern having dot-shaped convex portions) in which the resin portions 11 and 21 are independently formed on the substrates 21 and 22; Negative patterns (patterns with dot-shaped depressions) continuously formed on 21 and 22; patterns with doughnut-shaped projections; patterns with substantially C-shaped projections; A pattern having a portion that contacts and a portion that does not contact the object to be polished; a pattern that has a portion that contacts the object and a portion that does not contact the object in a grid pattern; and a portion that does not contact the object to be polished; a pattern that spirally has a portion that contacts the object to be polished and a portion that does not contact the object to be polished; or a pattern configured by combining these. Among them, a pattern having dot-shaped convex portions or a pattern having dot-shaped concave portions is preferable. By having such an uneven pattern, the polishing rate tends to be further improved. In the case of a pattern having dot-shaped protrusions, the three-dimensional shape of the dots is not particularly limited. Body shape, approximately semi-ellipsoidal shape, columnar shape (cylindrical shape, approximately cylindrical shape, elliptical columnar shape, approximately elliptical columnar shape, polygonal columnar shape), truncated cone shape (truncated cone shape, approximately truncated cone shape, truncated elliptical cone shape, approximately elliptical cone shape trapezoidal, polypyramidal truncated). Among the above, the truncated cone shape may be a truncated cone shape that expands from the substrate side toward the polishing surface side, or may be a truncated cone shape that expands from the polishing surface side toward the substrate side. Among these, a hemispherical shape or a substantially hemispherical shape is preferable from the viewpoint of more effectively and reliably exhibiting the effects of the present invention. Further, the three-dimensional shape of the spaces in the recesses in the case of the pattern having dot-shaped recesses can also be exemplified by the same three-dimensional shape as the three-dimensional shape in the case of the pattern having dot-shaped protrusions.

In the polishing pad of the present embodiment, it is preferable that the portions (convex portions) in contact with the object to be polished and the portions (concave portions) not in contact with the object to be polished form a regular pattern. By having a regular pattern, uniform polishing can be achieved, and polishing with excellent surface quality can be achieved. The term "regular pattern" refers to a pattern obtained by arranging a plurality of small patterns as a unit. Specifically, the regular pattern shown in FIG. 6A is composed of a plurality of small patterns P. In FIG. The small pattern used as a unit may be of one type or two or more types in combination.

When an arbitrary square region having a plane area of 4 cm ² is selected on the surface of the concave-convex pattern, the effective polishing area on the polishing surface per unit area (1 cm ² ) in that region (hereinafter referred to as “effective polishing area of the predetermined region”) ) is preferably 0.05 to 0.6 cm ² , more preferably 0.1 to 0.55 cm ² , still more preferably 0.15 to 0.5 cm ² . When the effective polishing area of the predetermined region is 0.05 cm ² or more, the area that can contribute to polishing is increased, the polishing rate is further improved, and the surface of the polished product is made more uniform. Further, when the effective polishing area of the predetermined region is 0.6 cm ² or less, the surface of the polished product is made more uniform and the polishing rate is further improved. The reason for this is to enable the supply and discharge of slurry containing free abrasive grains. Specifically, in the polishing pad of the present embodiment, as shown in regions S1 and S2 in FIG. obtain. Even in such a case, for example, the effective polishing area (gray portion) per unit area (1 cm ² ) in the 4 cm ² regions S1 and S2 is within a predetermined range, so that the polishing rate tends to be further improved. It is in.

When the uneven pattern is a pattern having dot-shaped protrusions or recesses, the number of uneven patterns is counted by the number of dot-shaped protrusions or recesses, and is preferably 5 to 5 per unit area (1 cm ² ) of the surface. The number is 80, preferably 15 to 75, even more preferably 30 to 70. The effective polishing area is calculated from the area A of the dot-shaped convex portions or the area B of the convex portions other than the dot-shaped concave portions, and is preferably 0.15 to 0.0 per unit area (1 cm ² ) of the surface. 0.7 cm ² , more preferably 0.2 to 0.65 cm ² , still more preferably 0.25 to 0.6 cm ² . When the area A of the dot-shaped protrusions or the area B of the protrusions other than the dot-shaped recesses is within the above range, the polishing rate tends to be further improved. Here, the "area A of the dot-shaped protrusions" refers to the area of the polishing surface 5 per unit area of the dot-shaped protrusions in contact with the pressure-sensitive paper 4 in the method for measuring the effective polishing area. The "area B of the protrusions other than the dot-shaped recesses" refers to the area of the polishing surface 5 per unit area of the protrusions in contact with the pressure-sensitive paper 4 in the method for measuring the effective polishing area.

When the uneven pattern has dot-shaped protrusions or recesses, the diameter of the dots (for example, the diameter represented by symbol L1 in FIG. 6(b)) is preferably 0.1 to 3 mm, more preferably 0. 0.5 to 2.5 mm, more preferably 1.0 to 2.0 mm. In addition, the closest distance between arbitrarily selected adjacent dots (for example, the distance between dots represented by symbol L2 in FIG. 6B) is preferably 0.1 to 3 mm, more preferably 0 0.5 to 2.5 mm, more preferably 1.0 to 2.0 mm. When the dot diameter and the closest distance between adjacent dots are within the above range, a concavo-convex pattern in which relatively small dots (convex portions or concave portions) are arranged at a relatively high density can be obtained. Rates tend to improve. When the planar shape of the dots is not circular, the diameter of the dots means the average value of the diameters connecting the center of gravity of the dots and the contour line.

The resin constituting the resin portion is not particularly limited. vinyl resins such as vinyl chloride, polyvinyl acetate and polyvinylidene fluoride; polysulfone resins such as polysulfone and polyethersulfone; acylated cellulose resins such as acetylated cellulose and butyrylated cellulose; polyamide resin; resin. Among these, polyurethane-based resins and acrylic-based resins are preferable, and polyurethane acrylate is more preferable. The use of such a resin tends to improve the polishing rate. In addition, resin which comprises a resin part may be used individually by 1 type, or may use 2 or more types together.

The Shore D hardness of the resin portion is preferably 60-95, more preferably 70-92.5, still more preferably 80-90. A Shore D hardness of 60 or more tends to further improve the polishing rate. Further, when the Shore D hardness is 95 or less, the adhesion to the object to be polished tends to be further improved. The Shore D hardness can be measured by the method described in Examples. Also, the Shore D hardness can be adjusted, for example, by selecting the type of resin to be used.

[Adhesive layer]
The polishing pad of the present embodiment may further include an adhesive layer on the side opposite to the resin portion of the base material for attaching the polishing pad to the polishing platen of the polishing machine. The adhesive layer may contain an adhesive or pressure-sensitive adhesive that is used in conventionally known polishing pads. Examples of materials for the adhesive layer include various thermoplastic adhesives such as acrylic adhesives, nitrile adhesives, nitrile rubber adhesives, polyamide adhesives, polyurethane adhesives, polyester adhesives, and silicone adhesives. agents. The adhesive layer may be, for example, double-sided tape.

[Anchor layer]
The polishing pad of this embodiment may have an anchor layer between the base material and the resin portion. Having the anchor layer tends to further improve the adhesion between the substrate and the resin portion. Although the material constituting the anchor layer is not particularly limited, for example, an acrylic resin coating agent can be used.

[Method for producing polishing pad]
The method for producing a polishing pad of the present embodiment includes an attaching step of attaching a curable composition onto a substrate, and a curing step of curing the attached curable composition to obtain a cured layer. The cured layer constitutes an uneven pattern alone or together with the base material, the surface of the uneven pattern has a polishing surface for polishing an object to be polished, and the polishing effective area on the polishing surface is the same as that of the surface. It is 0.05 to 0.60 cm ² per unit area (1 cm ² ), and the polishing surface does not substantially contain fixed abrasive grains.

[Adhesion process]
In the application step, the curable composition is applied onto the substrate so as to form a desired uneven pattern. The method of applying the curable composition onto the substrate is not particularly limited, but examples include gravure coater method, small diameter gravure coater method, reverse roll coater method, transfer roll coater method, kiss coater method, die coater method, and screen. Examples include a printing method and a spray coating method. Among these, the screen printing method is preferable from the viewpoint of easiness of forming a complicated concave-convex pattern.

(Curable composition)
The curable composition is not particularly limited, but for example, a photocurable composition containing a photopolymerization initiator and a polymerizable compound, a thermosetting composition containing a thermal polymerization initiator and a polymerizable compound, a thermosetting resin , a UV curable resin, and a curable composition containing a two-liquid mixed type curable resin. The curable composition may also contain a cross-linking agent having two or more polymerizable functional groups, if necessary.

Examples of polymerizable compounds include, but are not limited to, (meth)acrylates, epoxy (meth)acrylates, urethane (meth)acrylates, and polyester (meth)acrylates.

Examples of photopolymerization initiators include, but are not particularly limited to, benzophenone-based compounds, acetophenone-based compounds, and thiotisanthone-based compounds. Moreover, the thermal polymerization initiator is not particularly limited, and examples thereof include azo compounds such as 2,2'-azobisbutyronitrile and peroxides such as benzoyl peroxide (BPO).

Examples of thermosetting resins include, but are not limited to, phenol resins, epoxy resins, acrylic resins, urea resins, formaldehyde resins, and the like.

The UV curable resin is not particularly limited, but for example, a prepolymer having a number average molecular weight of about 1,000 to 10,000 is preferable. Reactive diluents and organic solvents can be used depending on the conditions. The two-liquid mixed type curable resin is not particularly limited, but prepolymers having different physical properties can be used, for example.

[Curing process]
The curing step is a step of curing the deposited curable composition to obtain a cured layer. The curing method is not particularly limited, but includes, for example, photocuring, heat curing, and the like.

The hardening layer has an uneven pattern on the surface opposite to the substrate, and the surface has a polishing surface for polishing the object to be polished. The effective polishing area of the polishing surface is 0.05 to 0.6 cm ² , preferably 0.1 to 0.55 cm ² , more preferably 0.15 to 0.1 cm 2 per unit area (1 cm ² ) of the surface. .5 cm ² . When the polishing effective area of the polishing surface is 0.05 cm ² or more, the polishing rate is further improved by increasing the area that can contribute to polishing. Also, the effective polishing area on the polishing surface is 0.6 cm ² or less, which further improves the polishing rate. The reason for this is to enable the supply and discharge of slurry containing free abrasive grains.

[Other processes]
The method for manufacturing the polishing pad of the present embodiment may have other steps, etc., if necessary. For example, after the adhesion step, there may be a step of volatilizing and removing at least part of the volatile components in the curable composition before the curing step. In addition, after the adhesion step and before the curing step and / or after the curing step, a step of removing a part of the curable composition or the cured layer in order to form a desired uneven pattern. may be Examples of the method of removal include cutting.

[Method for producing polished product]
The method for producing a polished product of the present embodiment is not particularly limited as long as it has a polishing step of polishing an object to be polished using the polishing pad in the presence of free abrasive grains. The polishing step may be a primary lapping polishing (rough lapping), a secondary lapping (finish lapping), or a polishing polishing. may

The object to be polished is not particularly limited, but for example, materials such as semiconductor devices and electronic parts, particularly Si substrates (silicon wafers), SiC (silicon carbide) substrates, GaAs (gallium arsenide) substrates, glass, hard disks and LCDs. Thin substrates (objects to be polished) such as substrates for (liquid crystal displays) can be mentioned. Among these, the method for producing a polished processed product of the present embodiment is a method for producing difficult-to-process materials that are difficult to polish, such as materials that can be applied to power devices, LEDs, and the like, such as sapphire, SiC, GaN, and diamond. It can be preferably used as. Among these, a semiconductor wafer is preferred, and a SiC substrate, a sapphire substrate, or a GaN substrate is preferred from the viewpoint of being able to more effectively utilize the effects of the polishing pad of the present embodiment. As the material, difficult-to-cut materials such as SiC single crystal and GaN single crystal are preferable, but single crystals such as sapphire, silicon nitride, and aluminum nitride may also be used.

[Polishing process]
The polishing step is a step of polishing an object to be polished using the polishing pad in the presence of loose abrasive grains. A conventionally known method can be used as the polishing method, and is not particularly limited.

In the polishing method, first, a polishing pad is attached to a predetermined position of the polishing apparatus. During this attachment, the polishing pad is attached so as to be fixed to the polishing apparatus via the adhesive layer described above. Then, the object to be polished, which is held on a holding surface plate arranged so as to face a polishing pad as a polishing surface plate, is pressed against the polishing surface side, and while polishing slurry containing diamond abrasive grains is supplied from the outside, polishing is performed. Rotate the pad and/or holding platen. As a result, the surface to be processed (surface to be polished) of the object to be polished is polished by the action of the abrasive grains supplied between the polishing pad and the object to be polished.

The polishing slurry preferably contains diamond abrasive grains and a dispersion medium for dispersing them. The content of diamond abrasive grains in the polishing slurry is not particularly limited, but from the viewpoint of more effectively performing the polishing process and suppressing the thickening of the work-affected layer on the object to be polished, the content of the diamond abrasive grains is 0 with respect to the total amount of the polishing slurry. 0.01 to 1.0% by weight is preferred.

The loose abrasive grains used in polishing are not limited to diamond abrasive grains, and may be, for example, silica or alumina. The average grain size of free abrasive grains is preferably 0.5 to 20 μm, more preferably 1 to 18 μm, still more preferably 2 to 15 μm, and particularly preferably 5 to 13 μm. When the average particle size of the diamond abrasive grains is within the above range, the polishing rate can be further improved and the occurrence of scratches on the work surface can be further suppressed.

Examples of the dispersion medium include water and organic solvents, and organic solvents are preferable from the viewpoint of further suppressing deterioration of the object to be polished. As the organic solvent, an organic solvent having a boiling point of about 110 to 300° C. is generally suitable. Commercially available organic solvents such as aliphatic and aromatic, cyclic hydrocarbons, esters, ethers, amines, amides, and ketones can be appropriately selected depending on the resin and workability. A solvent is used individually by 1 type or in combination of 2 or more types. In addition, the solvent may contain other additives as necessary. Such additives include, for example, polar compounds, specifically nonionic surfactants, anionic surfactants, carboxylic acid esters, carboxylic acid amides and carboxylic acids. Furthermore, various silicones and inorganic fine powders can be added as antifoaming agents, dispersants, leveling agents and viscosity improvers.

From the viewpoint of suppressing the temperature rise due to the friction between the polishing pad and the object to be polished during polishing, a solvent that does not contain abrasive grains and may contain additives is appropriately supplied to the polishing surface of the polishing pad. good too. Examples of such solvents and additives include those described above.

Although the present embodiment has been described above, the present invention is not limited to the above-described present embodiment. For example, as shown in the schematic cross-sectional view of FIG. 7, the resin portion may be formed by integrally and inseparably providing a convex portion having a polishing surface on a sheet-like portion. FIG. 7(a) shows, as an example, a polishing pad 30 having a resin portion 31 in which dot-shaped projections having a polishing surface are integrally and inseparably provided on a sheet-like portion. Also, the resin portion may be formed by cutting a part of the sheet-like portion to form an uneven pattern. FIG. 7(b) shows, as an example, a polishing pad 40 having a resin portion 41 in which the upper portion of the sheet-like portion is cut into dots to form dot-like concave portions.

Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is by no means limited by the following examples.

[Shore D hardness]
Shore D hardness was measured according to JIS (JIS K7311). In the measurement, a metal plate was laid under the polishing pad, and the measurement was performed under the same conditions as in the actual polishing process (the polishing pad was attached to the metal surface plate of the polishing apparatus).

[Effective Polishing Area and Effective Polishing Area of Predetermined Area]
The polishing surface (resin part surface) of the polishing pad is coated with the color-developing liquid of the pressure-sensitive paper, the polishing surface of the polishing pad coated with the color-developing liquid and the pressure-sensitive paper are superimposed, and the roller has a sufficiently large area for the uneven pattern. pressurized with After that, the polishing pad and the pressure-sensitive paper were separated, and the area transferred onto the pressure-sensitive paper was measured. The area of the transferred polishing surface per unit area (1 cm ² ) of the surface of the pressure-sensitive paper was defined as the effective polishing area of the polishing pad. In addition, an arbitrary square region of 2 cm square (4 cm ² ) is selected on the substrate surface, and the effective polishing area on the polishing surface per unit area (1 cm ² ) of the concave-convex pattern surface in that region is calculated, and the predetermined region is polished. Effective area is obtained.

[Area A and B when Concavo-convex Pattern Has Dot-Shaped Protrusions or Dot-Shaped Concavities]
A pressure-sensitive paper on which the polishing surface of the polishing pad was transferred was prepared in the same manner as in the method for measuring the effective polishing area. At this time, the pattern transferred to the pressure-sensitive paper corresponds to the convex portions of the concave-convex pattern, and the non-transferred portion in the projected area of the polishing pad onto the pressure-sensitive paper corresponds to the concave portion of the concave-convex pattern. Therefore, the area A of the dot-shaped convex portions or the area B of the convex portions other than the dot-shaped concave portions were obtained by measuring the transfer area to the pressure-sensitive paper.

[Polishing test]
A polishing pad was set at a predetermined position of a polishing apparatus via a double-sided tape, and a polishing test was conducted in which a 2-inch sapphire C wafer as an object to be polished was polished under the following conditions. In the polishing test, first, the polishing pad was dressed under the following dressing conditions, and polishing was performed under the following polishing conditions.
(dress condition)
Dress rotation speed: 70 rpm
Dressing pressure: 236gf/ ^cm2
Dressing time: 5min
(polishing conditions)
Surface plate rotation speed: 80 rpm
Surface pressure: 330 gf/cm ²
Lubricant high viscosity: V600
Polishing time: 30min
Abrasive grain: polycrystalline diamond (abrasive grain size 9 μm)

(polishing rate)
The polishing rate (unit: μm/h) is obtained by calculating the thickness removed by polishing from the amount of polishing obtained from the reduction in the mass of the object to be polished before and after the above polishing, the polishing area and the specific gravity of the object to be polished, and calculating the thickness per hour. was evaluated as the removed thickness of The thickness was calculated from the amount of polishing obtained from the reduction in mass of the object to be polished before and after processing, the area to be polished and the specific gravity of the object to be polished. The polishing test was performed on three sapphire C wafers, and the weighted average was taken as the polishing rate.

[Example 1]
UV coating agent (manufactured by Teikoku Ink Mfg. Co., Ltd., product name UV BOP) 100 parts by weight, photocurable monomer (manufactured by Shin-Nakamura Chemical Co., Ltd., product name TMM-360) 20 parts by weight, photocurable monomer (new Nakamura Chemical Co., Ltd., product name LMA) was mixed with 10 parts by weight to prepare a curable composition. On a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name Cosmoshine A4300 250 μm), which is a base material, hemispherical dots, which are dot-shaped convex portions, are screen-printed to form an uneven pattern shown in FIG. 6(a). The curable composition was applied in a regular array at . Thereafter, the curable composition was cured by UV irradiation with a UV device (manufactured by igraphics, product name: metal halide lamp, 120 W/cm) to form a resin portion. Finally, a double-sided tape (manufactured by 3M Company, product name: film-based double-sided adhesive tape 442JS) was attached as an adhesive layer to the opposite side of the base material from the resin portion to obtain a polishing pad of Example 1. The resulting polishing pad had a dot diameter of 1 mm, a closest distance between adjacent dots of 0.5 mm, a concavo-convex pattern per unit area of 69.8/cm ² , and an effective polishing area of 0.38 cm ² . , and the effective polishing area of the predetermined region was 0.38 cm ² .

[Example 2]
Except that 100 parts by weight of a softer material (manufactured by Teikoku Ink Mfg. Co., Ltd., product name UV FIL) was used instead of 100 parts by weight of the UV coating agent (manufactured by Teikoku Ink Mfg. Co., Ltd., product name UV BOP). A polishing pad of Example 2 was obtained in the same manner as in Example 1. The resulting polishing pad had a dot diameter of 1 mm, a closest distance between adjacent dots of 0.5 mm, a concavo-convex pattern per unit area of 69.8/cm ² , and an effective polishing area of 0.38 cm ² . , and the effective polishing area of the predetermined region was 0.38 cm ² .

[Example 3]
A polishing pad of Example 3 was obtained in the same manner as in Example 1, except that the dot diameter was 1.5 mm and the closest distance between adjacent dots was 0.5 mm. The obtained polishing pad had a concavo-convex pattern per unit area of 37 pieces/cm ² , an effective polishing area of 0.27 cm ² , and an effective polishing area of a predetermined region of 0.27 cm ² .

[Example 4]
A polishing pad of Example 4 was obtained in the same manner as in Example 1, except that the dot diameter was 1.0 mm and the closest distance between adjacent dots was 1.0 mm. The obtained polishing pad had a concavo-convex pattern per unit area of 37.2/cm ² , an effective polishing area of 0.16 cm ² , and an effective polishing area of a predetermined region of 0.16 cm ² .

[Example 5]
Instead of the concave-convex pattern shown in FIG. 6(a), dot-shaped concave portions in which the shape of the space in the concave portion is cylindrical are regularly arranged in the concave-convex pattern shown in FIG. 6(b). A polishing pad of Example 5 was obtained in the same manner as in Example 1, except that the curable composition was applied to the surface. The resulting polishing pad had a dot diameter of 0.5 mm, a closest distance between adjacent dots of 1.0 mm, a concave-convex pattern per unit area of 65.2/cm ² , and an effective polishing area of 0.55 cm. ² , and the effective polishing area of the predetermined region was 0.55 cm ² .

[Example 6]
A polishing pad of Example 6 was obtained in the same manner as in Example 5, except that the dot diameter was 2.0 mm and the closest distance between adjacent dots was 1.0 mm. The obtained polishing pad had a concavo-convex pattern per unit area of 16.8/cm ² , an effective polishing area of 0.48 cm ² , and an effective polishing area of a predetermined region of 0.48 cm ² .

[Comparative Example 1]
Polishing of Comparative Example 1 was performed in the same manner as in Example 1, except that a curable composition further containing 252 parts by weight of diamond abrasive grains (trade name: Diamond Powder TMD-S 8-16, manufactured by Trustwell Co.) was used. got a pad.

[Comparative Example 2]
(Primary impregnation step)
45.7 parts by mass of ester-based urethane resin (manufactured by DIC, trade name “Crisbon 7667”), 1.4 parts by mass of urethane prepolymer (manufactured by DIC, trade name “Barnock DN950”) as a cross-linking agent, N, 52.9 parts by mass of N-dimethylformamide was mixed to prepare a resin solution. The nonwoven fabric B was immersed in the obtained resin solution, and excess resin solution was squeezed off using a mangle roller, so that the nonwoven fabric B was substantially uniformly impregnated with the resin solution. Then, the nonwoven fabric B was immersed in a coagulating liquid consisting of water at 18° C. to coagulate and regenerate the primary impregnated resin to obtain a resin-impregnated nonwoven fabric. Thereafter, the resin-impregnated nonwoven fabric was taken out from the coagulating liquid and dried to obtain a resin-impregnated woven fabric from which the surface skin layer was removed by buffing.

(Immersion process)
Next, the resin-impregnated nonwoven fabric obtained above was immersed in an immersion solvent in which N,N-dimethylformamide and pure water were mixed at a ratio of 65:35. Thereafter, washing and drying were performed to obtain a resin-impregnated nonwoven fabric after the immersion step.

(Secondary impregnation step)
Further, 31.15 parts by mass of urethane prepolymer (manufactured by Mitsubishi Plastics, trade name "Novaretane UP121", NCO equivalent 440) and 7.85 parts by mass of curing agent (manufactured by DIC, trade name "Pandex E") , and 57.24 parts by mass of N,N-dimethylformamide to prepare a resin solution. The resin-impregnated nonwoven fabric after the immersion step was immersed in the obtained resin solution. After that, the polishing pad of Comparative Example 2 was obtained by washing and drying. The non-woven fabric content was 33% by mass based on the entire polishing pad.

[Comparative Example 3]
A polishing pad of Comparative Example 3 was obtained in the same manner as in Example 1, except that the dot diameter was 3 mm and the closest distance between adjacent dots was 5.5 mm. The resulting polishing pad had a concavo-convex pattern per unit area of 3.8/cm ² , an effective polishing area of 0.10 cm ² , and an effective polishing area of a predetermined region of 0.10 cm ² .

The polishing pad of the present invention has industrial applicability as a polishing pad for lapping and polishing glass substrates for optical materials, semiconductor devices, hard disks, and the like, particularly for lapping and polishing sapphire and SiC.

DESCRIPTION OF SYMBOLS 11,21,31...Resin part 12,22,32...Base material, 13,23...Adhesive layer, 4...Pressure-sensitive paper, 5...Abrasive surface, 6...Transferred coloring liquid, 10,20...Polishing pad

Claims (7)

comprising a base material and a resin part (excluding a structure comprising a fibrous substance and an adhesive) that serves as a convex part arranged separately on the base material,
The surface of the convex portion has a polishing surface for polishing an object to be polished,
The number of protrusions is 5 to 80 per unit area (1 cm ² ) of the surface,
an effective polishing area of the polishing surface is 0.15 to 0.70 cm ² per unit area (1 cm ² ) of the surface;
The polishing surface does not substantially contain fixed abrasive grains,
Shore D hardness of the resin portion is 60 to 95,
the substrate comprises a polyester-based film,
A polishing pad used for dressing . The convex portion has a dot shape,
The polishing pad according to claim 1. The area A of the dot-shaped protrusions is 0.15 to 0.70 cm ² per unit area (1 cm ² ) of the surface.
The polishing pad according to claim 2. The resin part contains polyurethane acrylate,
The polishing pad according to any one of claims 1-3. An adhesive layer is further provided on the side opposite to the resin portion of the base material,
The polishing pad according to any one of claims 1-4. an application step of applying a curable composition (excluding one containing a fibrous substance and an adhesive) onto a substrate;
a curing step of curing the adhered curable composition to obtain a cured layer;
The cured layer constitutes an uneven pattern alone or together with the base material,
The surface of the uneven pattern has a polishing surface for polishing an object to be polished,
an effective polishing area of the polishing surface is 0.15 to 0.70 cm ² per unit area (1 cm ² ) of the surface;
The polishing surface does not substantially contain fixed abrasive grains,
The Shore D hardness of the resin portion constituted by the cured layer is 60 to 95.
A method for manufacturing a polishing pad. A polishing step of polishing an object to be polished using the polishing pad according to any one of claims 1 to 5 in the presence of abrasive grains,
A method for producing an abrasive product.

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