JP6990993B2 - Polishing pad and its manufacturing method, and manufacturing method of polished products - Google Patents

Description

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

In recent years, as next-generation power semiconductor device materials, materials such as silicon carbide (SiC), gallium nitride (GaN), diamond (C), sapphire (Al2O3), and aluminum nitride (AlN), which are wide bandgap semiconductors, have attracted attention. There is. For example, silicon carbide (SiC) has excellent physical properties such as a band gap three times that of silicon (Si) and a dielectric breakdown electric field strength of about seven times, which is higher than that of current silicon semiconductors. It has excellent high-temperature operability, is compact, and has a high energy-saving effect. In addition, sapphire wafers are used for electronic devices with optical elements, such as high-performance projectors, because of their chemical stability, optical properties (transparency), mechanical strength, thermal properties (thermal conductivity), etc. It is becoming more important as a component. Toward the full-scale spread of these next-generation power devices, the diameter and mass production of substrates are being promoted, and along with this, the importance of substrate processing technology is increasing. In the processing process, similar to Si, a columnar single crystal (ingot) used for a wafer is sliced and cut into a disk shape. Next, the surface of the sliced disk-shaped single crystal is flattened. First, in order to roughly remove the roughness of the surface, a lapping process is performed using a lapping surface plate. After that, a polishing process is performed 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 surface. Then, 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 surface, a polishing process is performed. Therefore, it is important to improve the flatness of the disk-shaped single crystal surface by lapping and reduce fine scratches in order to affect the subsequent polishing process.

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

Japanese Unexamined Patent Publication No. 2007-61961 Japanese Unexamined Patent Publication No. 2009-72832

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

Further, the polishing sheet described in Patent Document 2 is used for general polishing processing of glass, ceramics, plastics, metals and the like. When a polishing sheet used for such a general polishing process 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 particles, and the abrasive particles buried in the polishing structure do not act as abrasive grains. There is room for further improvement in the polishing rate.

In addition to SiC, sapphire also has a modified Mohs hardness next to diamond and SiC, has high resistance to chemicals, and is extremely difficult to process. Therefore, in addition to general Si semiconductor wafers, polishing of materials expected as next-generation power semiconductor device materials, especially difficult-to-process materials with high hardness, is excellent in handleability and polishing rate. Pads are desired.

In response to the above problem, the present inventors set the area of the upper surface of the convex portion (effective polishing area) which has a convex portion pattern composed of resin at a predetermined density and contributes to polishing within a predetermined range. As a result, it has been found that it is possible to achieve a polishing pad which is excellent in handleability and maintenance manageability as compared with the above-mentioned metal surface plate, and which is particularly excellent in polishing rate in polishing difficult-to-cut materials.

Now, the present inventors have studied to further improve the product life in order to achieve further improvement in the product value of the polishing pad. Generally, in a polishing pad whose convex portion is made of resin, the convex portion gradually decreases as it is used for polishing, and the polishing rate decreases as the convex portion decreases. If the polishing rate decreases by more than a certain level, the polishing processing efficiency will decrease, so it will be replaced with a new polishing pad. From the viewpoint of improving the product life of the polishing pad, it is conceivable to increase the height of the convex portion and lengthen the time until the polishing rate decreases by a certain amount or more. However, as a result of the study by the present inventors, when the height of the convex portion is increased from the viewpoint of product life, in other words, when the groove between the convex portions is deeply formed, the abrasive grains become the groove between the convex portions. It has been found that the polishing rate is rather lowered due to being trapped.

The present invention has been made in view of the above circumstances, and is excellent in handleability and maintenance, a polishing pad which is particularly excellent in polishing rate in polishing difficult-to-cut materials and can achieve further improvement in product life. And a method for manufacturing the same, and a method for manufacturing a polished product using the polishing pad.

The present inventors have diligently studied to solve the above problems. As a result, they have found that the above-mentioned problems can be solved by a polishing pad having a polishing surface having a predetermined uneven pattern, and have completed the present invention.

That is, the present invention is as follows.
[1]
A polishing pad including a base material and a resin portion arranged on the base material.
The resin portion forms a concavo-convex pattern alone or together with the base material.
The uneven pattern is a pattern in which a plurality of convex portions having a polished surface are arranged.
The total area of the polished surface when the polishing pressure of 500 g / cm ² is applied to the convex portion is 0.05 to 0.8 cm ² per unit area (1 cm ² ) of the substrate surface.
The surface roughness Rz is 0.75 or less based on the average particle size of 1 to 18 μm of the free abrasive grains used for polishing as a reference 1.0.
The θ satisfying the following equation (1) is 5 to 60 °.
tan θ = t / ((L1-M1) / 2) ... (1)
t: Average height of the convex portion when a polishing pressure of 500 g / cm ² is applied to the convex portion L1: Average circle-equivalent diameter of the bottom surface of the convex portion M1: Polishing pressure of 500 g / cm ² is applied to the convex portion. A polishing pad having a diameter equivalent to an average circle on the upper surface of the convex portion when the protrusion is formed.
[2]
The average height t of the convex portion is 0.06 to 1 mm.
The polishing pad according to [1].
[3]
The average circle-equivalent diameter L1 of the convex portion is 1 to 5 mm.
The polishing pad according to any one of [1] and [2].
[4]
The closest contact distance L2 of the adjacent convex portions is 0.1 to 3 mm.
The polishing pad according to any one of [1] to [3].
[5]
The resin portion contains at least one selected from the group consisting of an epoxy resin, an acrylic resin, a polyester resin, an unsaturated polyester resin, a polyamide resin, and a polyurethane resin.
The polishing pad according to any one of [1] to [4].
[6]
An adhesive layer is further provided on the side of the base material opposite to the resin portion.
The polishing pad according to any one of [1] to [5].
[7]
The polished surface is substantially free of fixed abrasive grains.
The polishing pad according to any one of [1] to [6].
[8]
The method for manufacturing a polishing pad according to any one of [1] to [7].
The present invention comprises a step of forming a resin portion having a concavo-convex pattern in which a plurality of convex portions having a polished surface are arranged on a substrate by a screen printing method, an exposure plate making method, or a molding method.
How to make a polishing pad.
[9]
A polishing step of polishing an object to be polished using the polishing pad according to any one of [1] to [7] in the presence of free abrasive grains.
Manufacturing method of polished products.
[10]
The average particle size of the free abrasive grains is 0.25 to 18 μm.
[9] The method for manufacturing a polished product according to [9].

According to the present invention, a polishing pad having excellent handleability and maintainability, particularly having an excellent polishing rate in polishing difficult-to-cut materials, and being able to further improve the product life, and a method for manufacturing the polishing pad, and a method thereof. It is possible to provide a method for manufacturing a polished product using a polishing pad.

It is a schematic perspective view which shows an example of the polishing pad of this embodiment. It is a perspective view and sectional drawing of the convex part of this embodiment. It is a schematic diagram which shows the measuring method of the area (polishing effective area) of a polishing surface when a polishing pressure is applied to a convex part. It is a schematic diagram which shows an example of the unevenness pattern of this embodiment.

Hereinafter, embodiments for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. In addition, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown.

[Polishing pad]
The polishing pad of the present embodiment is a polishing pad including a base material and a resin portion arranged on the base material, and the resin portion constitutes an uneven pattern alone or together with the base material. The uneven pattern is a pattern in which a plurality of convex portions having a polished surface are arranged, and the total area of the polished surface when a polishing pressure of 500 g / cm ² is applied to the convex portions is the sum of the areas of the base material surface. It is 0.05 to 0.8 cm ² per unit area (1 cm ² ), and θ that satisfies the following formula (1) is 5 to 60 °.
tan θ = t / ((L1-M1) / 2) ... (1)
t: Average height of the convex portion when a polishing pressure of 500 g / cm ² is applied to the convex portion L1: Average circle-equivalent diameter of the bottom surface of the convex portion M1: Polishing pressure of 500 g / cm ² is applied to the convex portion. Average circle-equivalent diameter of the upper surface of the convex portion when

In the present embodiment, the total area of the polished surface when a polishing pressure of 500 g / cm ² is applied to the convex portion per unit area (1 cm ² ) of the surface of the base material is also simply referred to as "effective polishing area". .. Further, θ satisfying the above equation (1) is also simply referred to as “average angle θ”.

FIG. 1 shows a schematic perspective view showing an example of the polishing pad of the present embodiment. As shown in FIG. 1, the polishing pad 10 includes a base material 12 and a resin portion 11 arranged on the base material 12, and the resin portion 11 constitutes an uneven pattern together with the base material 12. .. The uneven pattern is a pattern in which a plurality of cone-shaped dots formed by the resin portion 11 are arranged on the surface of the base material 12. Further, the polishing pad of the present embodiment may have an adhesive layer 13 if necessary.

Since the polishing pad of the present embodiment has a base material and a resin portion arranged on the base material, it is lighter than a metal-based surface plate and can be disposable after a predetermined number of polishing times. And excellent in maintainability. Further, this polishing pad has a concavo-convex pattern, and has an effective polishing area within the above numerical range on the polished surface of the concavo-convex pattern surface, so that the polishing rate is excellent and the polishing rate is comparable to that of a metal surface plate. can do. This is done by (1) interposing free abrasive grains such as diamond abrasive grains between the object to be polished and the convex portion in close contact with the object to be polished, thereby effectively forming the convex portion and the free abrasive grains. It can act on (polish) the object to be polished, (2) by providing a recess, the pressing force per unit area on the surface in close contact with the object to be polished increases, and (3) the above numerical range. It is considered that this is because the balance between (1) and (2) can be made excellent by having the polishing effective area inside. However, the factors are not limited to this. Further, when the uneven pattern is regular, more uniform polishing is possible, and polishing with excellent surface quality can be achieved.

Further, as shown in FIG. 2, the centrifugal force F1 due to the rotation of the polishing pad and the gravity F2 of the abrasive grains themselves are applied to the abrasive grains AG released in the polishing step. In order for the abrasive grains to reach the upper surface of the convex portion 11a, the force for climbing the slope determined by the centrifugal force F1 acting in the surface direction of the polishing pad and the average angle θ is larger than the gravity F2 for descending the slope. , Need to grow. From such a viewpoint, in the present embodiment, the convex portion 11a of the polishing pad is polished so that the abrasive grain AG polishes the object to be polished by setting the average angle θ of the convex portion 11a within a predetermined range. It is possible to reach the upper surface of the convex portion 11a constituting the surface.

〔Base material〕
The base material is not particularly limited, but is, for example, a polyester-based film such as polyethylene terephthalate, polypropylene terephthalate, or polybutylene terephthalate; a polyolefin-based film such as polyethylene (PE) film, polypropylene (PP) film, or ethylene-propylene copolymer film. Films: Polyetheretherketone (PEEK) films, polyphenylene sulfide (PPS) films, and the like. The base material may be any as long as it can print a resin described later 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 portion is arranged on the base material and constitutes an uneven pattern alone or together with the base material. The surface of the resin portion on the opposite side of the base material serves as a polishing surface for polishing the object to be polished. In the polishing pad of the present embodiment, it is preferable that the polishing surface does not substantially contain fixed abrasive grains. "Substantially free of fixed abrasive grains" means that the abrasive grains do not appear on the polished surface which is the surface of the resin portion. Since the polished surface does not substantially contain abrasive grains, it is possible to increase the area of the polished surface on which the free abrasive grains stay.

(Effective polishing area)
The effective polishing area is 0.05 to 0.8 cm ² per unit area (1 cm ² ) of the surface, preferably 0.1 to 0.8 cm ² , and more preferably 0.15 to 0.75 cm ² . It is more preferably 0.2 to 0.7 cm ² , and particularly preferably 0.25 to 0.7 cm ² . When the effective polishing area is 0.05 cm ² or more, the area that can contribute to polishing increases, and the polishing rate is further improved. Further, when the effective polishing area is 0.8 cm ² or less, the recesses are relatively increased, and the efficiency of supply / discharge of the slurry containing the free abrasive grains is further improved.

Here, the "effective polishing area" is the area of the upper surface of the convex portion that contributes to polishing in the uneven pattern when a polishing pressure of 500 g / cm ² is applied per unit area (1 cm ² ). The method for measuring the effective polishing area is not particularly limited as long as it is a method for measuring by applying a polishing pressure of 500 g / cm ² per unit area (1 cm ² ).

For example, the glass plates are superposed on the polished surface of the polishing pad 10 (the surface of the resin portion 11) so as to be in contact with each other, and a weight having a polishing pressure of 500 gf / cm ² is placed on them so that a uniform load is applied to them. The area of the upper surface (polished surface) per convex part that comes into contact with the glass plate can be measured with a microscope, and this can be used as the polishing area per convex part that contributes to polishing in the uneven pattern. can.

Further, as another method, as shown in FIG. 3, the pressing plate 4 for measuring the effective polishing area and the flat surface of the pressure sensitive paper 5 are brought into direct contact with the polished surface (surface of the resin portion 11) of the polishing pad 10. The convex pattern is transferred to the pressure sensitive paper 5 by superimposing them and applying a transfer pressure corresponding to a polishing pressure of 500 gf / cm ² with a roller or the like having a sufficiently large area with respect to the uneven pattern so that the load is uniformly applied. After that, the area of the upper surface (polished surface 6) per convex portion transferred to the pressure-sensitive paper 5 can be measured, and this can be used as the polishing area per convex portion that contributes to polishing in the uneven pattern. .. If the transfer is not sufficient, apply the color-developing liquid of pressure-sensitive paper directly to the polished surface of the polishing pad 10 (the surface of the resin portion 11), and perform the above measurement on the polished surface (resin portion surface) of the applied polishing pad. You can also do it.

Next, 10 points of the polished surface per convex portion obtained as described above are arbitrarily extracted, the circle-equivalent diameter of the polished surface per convex portion is obtained, and the obtained circle-equivalent diameter is weighted average. By doing so, the average circle-equivalent diameter M1 of the upper surface of the convex portion is calculated. The equivalent circle area per convex portion can be obtained from the average circle equivalent diameter M1 and the effective polishing area can be calculated by multiplying the number of convex portions per unit area (1 cm ² ) of the substrate surface by the equivalent circle area. can.
Effective polishing area = (average circle equivalent diameter M1) x (number of convex portions per unit area (1 cm ² ) of the substrate surface)

In the calculation of the average circle equivalent diameter M1, the transferred convex portion pattern is converted into image data by a flatbed scanner or a digital camera, and the obtained image data is binarized and binarized. From the part pattern, 10 convex parts are arbitrarily extracted, the circle-equivalent diameter of each convex part is obtained, and the obtained circle-equivalent diameter is weighted and averaged to calculate the average circle-equivalent diameter M1 of the upper surface of the convex part. You may. The binarization process can be calculated using general binarization processing software, but it can be calculated by setting the threshold value to 220 using, for example, "Pick Map Version 2.4". can.

The effective polishing area (cm ² ) can be adjusted by dressing or buffing, which will be described later. Specifically, the effective polishing area (cm ² ) of the polished surface is preferably 0.2 to 0.8 cm ² , more preferably 0.3 to 0.75 cm ² , and further preferably 0.4 to 0.7 cm. Can be adjusted to ² .

[Convex part]
In the present embodiment, the upper surface of the convex portion is a polishing surface that comes into contact with the object to be polished. From the viewpoint of improving the polishing rate, it is desirable to adjust the shape of the convex portion so that free abrasive grains are likely to be present on the upper surface of the convex portion, and from the viewpoint of improving the product life, the height of the convex portion is increased. High is desired. Therefore, in the present embodiment, the convex portion is configured so that θ satisfying the following equation (1) is 5 to 60 °.
tan θ = t / ((L1-M1) / 2) ... (1)
t: Average height of the convex portion when a polishing pressure of 500 g / cm ² is applied to the convex portion L1: Average circle-equivalent diameter of the bottom surface of the convex portion M1: Polishing pressure of 500 g / cm ² is applied to the convex portion. Average circle-equivalent diameter of the upper surface of the convex portion when

In the present embodiment, examples of the shape of the cross section of the convex portion include a trapezoidal shape, a triangular shape, a semicircular shape, and a substantially semicircular shape. In a trapezoidal shape or a triangular shape, in addition to a shape composed of straight lines in a strict sense, if the vertices of each shape are defined, the sides may be composed of distorted straight lines (curves). ..

The shape of such a convex portion is not particularly limited, and examples thereof include a frustum shape such as a frustum shape, a substantially frustum shape, an elliptical frustum shape, a substantially elliptical frustum shape, and a polygonal frustum shape. .. The protrusions in contact with the object to be polished preferably form a regular pattern. By having a regular pattern, uniform polishing is possible, and polishing with excellent surface quality can be achieved. The "regular pattern" refers to a pattern obtained by arranging a plurality of small patterns as units. Specifically, the regular pattern shown in FIG. 4 is composed of a plurality of small patterns P. The small pattern as a unit may be one type or two or more types may be used in combination.

(Average angle θ)
The average angle θ is 5 to 60 °, preferably 10 to 55 °, and more preferably 15 to 50 °. When the average angle θ is 5 ° or more, the effective polishing area is not reduced more than necessary, and the polishing rate is further improved. Further, when the average angle θ is 60 ° or less, the abrasive grains can easily climb the hypotenuse of the convex portion, so that more free abrasive grains can be present on the upper surface of the convex portion. As a result, the polishing rate is further improved.

If the convex portion has a truncated cone shape or a conical shape, the upper surface and the bottom surface of the convex portion have a substantially uniform circular shape when a polishing pressure of 500 g / cm ² is applied, and the slope of the convex portion is formed from any direction. Even if the abrasive grains rise, the way they rise is almost uniform. On the other hand, when the convex portion has a polygonal pyramid shape or a polygonal pyramid shape, the upper surface and the bottom surface of the convex portion have a polygonal shape, and there may be a steep slope depending on the direction in which the abrasive grains rise on the slope of the convex portion. There is also a gentle slope. In such a polygonal frustum or polygonal pyramid, there are comparatively gentle hypotenuses where free abrasive grains easily rise and steep hypotenuses where it is difficult to climb, but from a macroscopic point of view, the average angle formed by each hypotenuse exists. Can be used as an index to evaluate the ease of climbing of free abrasive grains. Therefore, in the calculation of the "average angle θ" in the present embodiment, the diameters of circles having a circle area equal to the areas of the upper surface and the bottom surface of the convex portion, that is, the average circle equivalent diameters L1 and M1 are used.

Further, if the convex portion has a truncated cone shape, a conical shape, a polygonal pyramid shape, or a polygonal pyramid shape, the slope on which the abrasive grains rise is a substantially uniform surface. On the other hand, when the convex portion is hemispherical or substantially hemispherical, the slope on which the abrasive grains rise may be steep or gentle depending on the position of the abrasive grains. In such a hemispherical or substantially hemispherical shape, there are comparatively gentle points where free abrasive grains easily rise and steep points where it is difficult to climb, but from a macroscopic point of view, the average angle formed by the hypotenuse is used as an index. , The ease of climbing of free abrasive grains can be evaluated. Therefore, in the calculation of the "average angle θ" in the present embodiment, the tan θ calculated by the average circle equivalent diameters L1 and M1 and the height t is used.

(Diameter equivalent to average circle L1)
The average circle-equivalent diameter L1 is preferably 1 to 5 mm, more preferably 1.5 to 4.5 mm, and even more preferably 2 to 4 mm. Since the diameter L1 corresponding to the average circle is 1 mm or more, the height t can be designed higher while maintaining a predetermined average angle θ, so that the product life tends to be further improved. Further, when the diameter L1 corresponding to the average circle is 5 mm or less, the convex portion becomes smaller, the concave portion relatively increases, and the efficiency of supply / discharge of the slurry containing the free abrasive grains tends to be further improved.

The average circle-equivalent diameter L1 can be measured from a micrograph of the surface of the polishing pad. Further, since the change in the average circle-equivalent diameter L1 before and after the pressurization of the polishing pressure of 500 g / cm ² is negligible, the one before the pressurization of the polishing pressure of 500 g / cm ² may be adopted. The calculation of the average circle-equivalent diameter L1 is the same as the calculation of the average circle-equivalent diameter M1 of the upper surface of the convex portion. It can be calculated by weighted averaging the obtained circle-equivalent diameters.

(Diameter equivalent to average circle M1)
The average circle-equivalent diameter M1 is preferably 0.2 to 3.5 mm, more preferably 0.3 to 3 mm, and even more preferably 0.4 to 2.5 mm. Since the diameter M1 corresponding to the average circle is 0.2 mm or more, the height t can be designed higher while maintaining the predetermined average angle θ, so that the product life tends to be further improved. Further, when the diameter M1 corresponding to the average circle is 3.5 mm or less, the convex portion becomes smaller, the concave portion relatively increases, and the efficiency of supply / discharge of the slurry containing the free abrasive grains tends to be further improved. .. The method for calculating the average circle-equivalent diameter M1 is as described above.

(Height t)
Further, the force applied to the abrasive grains AG changes in a complicated manner in the polishing process, and a constant amount of centrifugal force F1 is not always applied to the abrasive grains AG, and the centrifugal force F1 always causes the abrasive grains to be on the slope of the convex portion. It is not always the case that you are participating in the direction of climbing. In order for the abrasive grain AG placed in such a complicated force field to reach the upper surface of the convex portion 11a, it is also important to balance the average angle θ with the height t of the convex portion 11a, which is related to the length of product life. It becomes. From this point of view, the average height t of the convex portion when a polishing pressure of 500 g / cm ² is applied is preferably 0.06 to 1 mm, more preferably 0.1 to 0.9 mm, and further. It is preferably 0.2 to 0.8 mm. When the average height t of the convex portion is 0.06 mm or more, the product life tends to be further improved. Further, when the average height t of the convex portion is 1 mm or less, the free abrasive grains easily reach the upper surface of the convex portion, so that the polishing rate tends to be further improved.

The method for measuring the average height t is not particularly limited as long as it is a method in which a polishing pressure of 500 g / cm ² is applied per unit area (1 cm ² ). For example, in the method of measuring the area of the polished surface in contact with the glass plate, the average height t can be obtained by measuring the average distance between the base material and the glass plate. Further, when the pressure-sensitive paper is used, the average distance between the base material 12 and the pressure-sensitive paper 5 can be measured and obtained.

The surface roughness Rz of the polished surface shall be the roughness of the maximum height defined by JIS B0633: 2001 (ISO4288: 1996).

The surface roughness Rz of the polished surface is preferably 0.1 to 20 μm, more preferably 0.15 to 18 μm, and further preferably 0.2 to 16 μm.

As one embodiment, when the resin portion is composed of a photocurable resin or a photosensitive resin, more specifically, an acrylic resin, a polyester resin, an unsaturated polyester resin, a polyamide resin, and a polyurethane resin, the resin portion is composed of a photocurable resin or a photosensitive resin. The surface roughness Rz of the polished surface is preferably 0.1 to 3 μm, more preferably 0.15 to 2 μm, still more preferably 0.2 to 1 μm, depending on the relationship with the physical properties such as the hardness of the resin. be. When the surface roughness Rz of the polished surface is 0.1 μm or more, the free abrasive grains that have reached the upper surface of the convex portion tend to stay on the upper surface of the convex portion, so that the polishing rate tends to be further improved. Further, since the surface roughness Rz of the polished surface is 3 μm or less, the waviness of the surface is suppressed, the abrasive grains tend to stay on the polished surface, and the homogeneity and flatness of the polished surface are maintained. The surface quality of the polished material tends to be improved.

As another embodiment, when the resin portion is composed of a thermosetting resin, more specifically, an epoxy resin or a phenol resin, the surface of the polished surface may be affected by the relationship with the physical properties such as the hardness of the resin. The roughness Rz is preferably 1 to 20 μm, more preferably 2 to 18 μm, and even more preferably 3 to 16 μm. When the surface roughness Rz of the polished surface is 1 μm or more, the free abrasive grains that have reached the upper surface of the convex portion tend to stay on the upper surface of the convex portion, so that the polishing rate tends to be further improved. Further, since the surface roughness Rz of the polished surface is 20 μm or less, the waviness of the surface is suppressed, the abrasive grains tend to stay on the polished surface, and the homogeneity and flatness of the polished surface are maintained. The surface quality of the polished material tends to be improved. The surface roughness Rz of the polished surface can be adjusted by a dressing treatment, a buffing treatment, or the like, which will be described later. Specifically, the surface roughness Rz of the convex portion (polished surface) can be adjusted to preferably 1 to 7 μm, more preferably 2 to 6 μm, and further preferably 3 to 5 μm.

Further, the surface roughness Rz is preferably 0.75 or less, more preferably 0.65 or less, still more preferably 0.65 or less, with the average particle size of the free abrasive grains used being 0.25 to 18 μm as a reference 1.0. It is 0.6 or less. When the surface roughness Rz satisfies the above range in relation to the free abrasive grains used, the free abrasive grains that have reached the upper surface of the convex portion tend not to be buried in the grooves of the polished surface and tend to stay easily.

The closest contact distance between adjacent convex portions (for example, the distance between the convex portions represented by the reference numeral L2 in FIG. 4) is preferably 0.1 to 3 mm, more preferably 0.5 to 0.5 mm. It is 2.5 mm, more preferably 1.0 to 2.0 mm. When the closest contact distance between adjacent convex portions is within the above range, an uneven pattern in which relatively small convex portions are arranged at a relatively high density can be obtained, so that the polishing rate tends to be further improved. ..

The number of convex portions per unit area (1 cm ² ) is preferably 4 to 80, more preferably 6 to 75, and even more preferably 9 to 70. When the number of convex portions per unit area is 4 or more, the slurry supply / discharge capacity containing free abrasive grains is excellent, and the polishing rate tends to be improved. When the number of convex portions per unit area is 80 or less, the height per convex portion can be made higher, and the product life tends to be further improved. The number of convex portions per unit area can be calculated by visually checking the number of convex portions having a predetermined area, for example, 4 cm ² (2 cm square), and converting the number into the number per unit area.

The resin constituting the resin portion is not particularly limited, and is, for example, an epoxy resin such as a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a phenol novolac type epoxy resin, and a cresol novolac type epoxy resin. Polyester resin such as polyethylene terephthalate and polybutylene terephthalate; unsaturated polyester resin; polyamide resin such as polyether amide, polyether ester amide, ammonium salt type tertiary nitrogen atom-containing polyamide; ether or ester in the molecule Polyurethane-based resins such as polyurethanes, polyurethane polyureas, polyurethane acrylates, and addition polymers of amide compounds and isocyanate compounds with bonds; acrylic resins such as polyacrylates and polyacrylonitriles; polyvinyl chlorides, polyvinylacetates, polyvinylidene fluorides, etc. Examples thereof include vinyl-based resins; polysulfone-based resins such as polysulfone and polyether sulfone; acylated cellulose-based resins such as acetylated cellulose and butyrylated cellulose; and polystyrene-based resins. Of these, epoxy resins, unsaturated polyester resins, polyamide resins, and polyurethane resins are preferable. By using such a resin, the polishing rate tends to be further improved. The resin constituting the resin portion may be used alone or in combination of two or more.

[Adhesive layer]
The polishing pad of the present embodiment may further include an adhesive layer for attaching the polishing pad to the polishing surface plate of the polishing machine on the side opposite to the resin portion of the base material. The adhesive layer may contain an adhesive or an adhesive used in conventionally known polishing pads. Examples of the material of 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. The agent is mentioned. The adhesive layer may be, for example, double-sided tape.

[Anchor layer]
The polishing pad of the present embodiment may have an anchor layer between the base material and the resin portion. By having the anchor layer, the adhesion between the base material and the resin portion tends to be further improved. The material constituting the anchor layer is not particularly limited, and examples thereof include an acrylic resin coating agent.

[Manufacturing method of polishing pad]
The method for manufacturing a polishing pad of the present embodiment is a step of forming a resin portion having a concavo-convex pattern in which a plurality of convex portions having a polished surface are arranged on a substrate by a screen printing method, an exposure plate making method, or a molding method. Has.

[Screen printing method]
In the screen printing method (stencil printing), a screen mask made so as to be able to form a pattern of convex portions is prepared, and the curable composition is printed on a substrate using the screen mask and cured. From the viewpoint of forming a fine uneven pattern, the viscosity of the resin liquid is preferably low, and from this viewpoint, the resin type can be selected. According to the screen printing method, it is possible to form a convex portion having a relatively small average angle θ. Further, in relative comparison with the exposure plate making method, it is possible to use a thermosetting resin, a photocurable resin, etc. in the screen printing method, and there is an advantage that a wide range of resin types can be selected. be.

Further, when a photocurable resin is used, the surface roughness Rz of the obtained convex portion (polished surface) is preferably 0.1 to 3 μm, more preferably 0.15 to 2 μm, still more preferably 0. It tends to be easy to adjust to 2 to 1 μm.

On the other hand, when a thermosetting resin is used, the surface roughness Rz of the obtained convex portion (polished surface) is preferably adjusted to 1 to 20 μm, more preferably 2 to 18 μm, and further preferably 3 to 16 μm. It tends to be easy to do. Further, the surface roughness Rz of the convex portion (polished surface) may be adjusted to preferably 1 to 7 μm, more preferably 2 to 6 μm, and further preferably 3 to 5 μm by a dressing treatment described later.

In the screen printing method, the method for increasing the height t is not particularly limited, and for example, a method for increasing the height t relatively by increasing the diameter L1 corresponding to the average circle on the bottom surface of the convex portion can be mentioned. Be done.

(Curable composition)
The curable composition is not particularly limited, and is, 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, and a thermosetting resin. , UV curable resin, a curable composition containing a two-component mixed type curable resin, and the like. Further, the curable composition may contain a cross-linking agent or the like having two or more polymerizable functional groups, if necessary.

The polymerizable compound is not particularly limited, and examples thereof include (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate.

The photopolymerization initiator is not particularly limited, and examples thereof include benzophenone-based compounds, acetophenone-based compounds, and thiothysanton-based compounds. The thermal polymerizable initiator is not particularly limited, and examples thereof include azo compounds such as 2,2'-azobisbutyronitrile and peroxides such as benzoyl peroxide (BPO).

The thermosetting resin is not particularly limited, and examples thereof include a phenol resin, an epoxy resin, an acrylic resin, a urea resin, and a formaldehyde resin.

The UV curable resin is not particularly limited, but for example, a prepolymer having a number average molecular weight of about 1000 to 10000 is preferable, and examples of the material include an acrylic (methacrylic) ester resin, a urethane modified resin thereof, and a thiocol resin. A reactive diluent or an organic solvent can be appropriately used depending on the intended use.

The two-component mixed type curing resin is not particularly limited, but for example, prepolymers having different physical properties can be used, and examples thereof include epoxy resins, unsaturated polyester resins, and polyamide resins.

(Curing process)
In addition to the screen printing step, the method for manufacturing a polishing pad of the present embodiment may include a curing step of curing the curable resin. The curing step is a step of curing the adhered curable composition to obtain a cured layer. The curing method is not particularly limited, and examples thereof include photocuring and thermosetting. The cured layer has an uneven pattern on the surface opposite to the base material, and the surface has a polished surface for polishing the object to be polished.

(Other processes)
The polishing pad manufacturing method of the present embodiment may include other steps and the like, if necessary. For example, it may have a step of volatilizing and removing at least a part of the volatile components in the curable composition after the screen printing step and before the curing step. Further, there is a step of removing a part of the curable composition or the cured layer in order to form a desired uneven pattern after the screen printing step and before the curing step and / or after the curing step. You may be doing it. As a method of removing, for example, cutting may be mentioned.

[Exposure plate making method]
In the method for manufacturing a polishing pad of the present embodiment, a plate-making method for letterpress can be applied as a method for molding the convex portion. In the exposure plate making method, first, a step of joining a base material and a photosensitive resin plate (solid state at room temperature) and a negative or positive film capable of recording a convex pattern on the surface of the photosensitive resin plate are formed. A method having a step of bringing them into close contact, a step of exposing a photosensitive resin plate via a negative or a positive film, and a step of peeling off the negative or the positive film to wash away an unexposed portion and developing the exposed portion as a convex portion. can give. Further, in the method, as other steps, a step of drying the convex portion pattern by hot air drying, or post-exposure for the purpose of improving the adhesion between the base material and the convex portion and improving the hardness of the convex portion may be performed. good.

In the method of manufacturing a polishing pad applying such a plate making method for a relief plate, in order to obtain a predetermined average angle θ and the like, the exposure light can easily wrap under the negative or positive film not only directly above but also diagonally. It may be exposed or the holes in the negative or positive film may be tapered. With such a method, unlike the screen printing method in which it is difficult to form a high convex portion, the height t can be easily increased only by using a thicker photosensitive resin plate. Further, as described above, it is also possible to enable an average angle θ.

The resin constituting the photosensitive resin plate is not particularly limited, and is, for example, a polyether amide, a polyether ester amide, an ammonium salt type tertiary nitrogen atom-containing polyamide, an amide compound having one or more amide bonds, and an organic diisocyanate. Examples thereof include an addition polymer of a compound, an addition polymer of a diamine having no amide bond and an organic diisocyanate compound, and the like. Further, it is more preferable that the above-mentioned photopolymerization initiator is contained.

[Molding method]
In the method for manufacturing a polishing pad of the present embodiment, a convex pattern can be transferred and formed on a polishing layer by using a molding plate (mold). A process of producing a plate consisting of an uneven pattern in which a plurality of recesses are arranged, a process of pouring a curable resin into the recesses of the plate, a process of joining a base material to a curable resin and a plate, and a process of curing the curable resin. It is also possible to transfer and form the convex pattern on the polishing layer by a step of peeling the curable resin from the plate. A rubber plate, a resin plate, or the like can be used as the plate. Examples of the curable resin include the above-mentioned thermosetting resin, photocurable resin, and two-component curable resin. Examples of the molding method include a gravity casting method in which the mold and the resin are poured into a mold by the weight of the resin itself at normal temperature and pressure, and a vacuum casting method in which the mold and the resin are placed in a vacuum container, depressurized and pushed in at atmospheric pressure.

Further, after the screen printing method, the exposure plate making method, or the molding method, the surface of the uneven pattern may be prepared by dressing or buffing.

[Manufacturing method of polished products]
The method for producing the polished product of the present embodiment is not particularly limited as long as it has a polishing step of polishing the object to be polished using the above-mentioned polishing pad in the presence of free abrasive grains. The polishing step may be primary wrapping polishing (coarse wrapping), secondary wrapping (finish wrapping), or polishing polishing, and of these, a plurality of of these may be combined. You may.

The object to be polished is not particularly limited, but is, for example, a material such as a semiconductor device or an electronic component, particularly a Si substrate (silicon wafer), a SiC (silicon carbide) substrate, a GaAs (gallium arsenide) substrate, glass, a hard disk, or an LCD. Examples thereof include thin substrates (objects to be polished) such as substrates for (liquid crystal displays). Among these, the method for manufacturing a polished product of the present embodiment is a method for manufacturing a difficult-to-polish material such as sapphire, SiC, GaN, and diamond, which can be applied to power devices, LEDs, and the like. Can be suitably used as. Among these, a semiconductor wafer is preferable, and a SiC substrate, a sapphire substrate, or a GaN substrate is preferable from the viewpoint that the action and effect of the polishing pad of the present embodiment can be more effectively utilized. As the material, a difficult-to-cut material such as a SiC single crystal or a GaN single crystal is preferable, but a single crystal of sapphire, silicon nitride, aluminum nitride or the like may be used.

[Polishing process]
The polishing step is a step of polishing the object to be polished using the above-mentioned polishing pad in the presence of free abrasive grains. As the polishing method, a conventionally known method can be used and is not particularly limited.

In the polishing method, first, a polishing pad is attached to a predetermined position of the polishing device. At the time of this mounting, the polishing pad is mounted so as to be fixed to the polishing device via the above-mentioned adhesive layer. Then, the object to be polished held on the holding surface plate arranged so as to face the polishing pad as the polishing surface plate is pressed against the polishing surface side, and polishing is performed while supplying the polishing slurry containing diamond abrasive grains from the outside. Rotate the pad and / or holding platen. As a result, the machined surface (polished surface) 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 the diamond abrasive grains. The content ratio 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-altered layer in the object to be polished, it is 0 with respect to the total amount of the polishing slurry. It is preferably 0.01 to 1.0% by weight.

The free abrasive grains used in polishing are not limited to diamond abrasive grains, and may be, for example, silica or alumina. The average particle size of the free abrasive grains is preferably 0.25 to 18 μm, more preferably 0.5 to 18 μm, still more preferably 1 to 15 μm, and particularly preferably 2 to 13 μm. The larger the average particle size of the abrasive grains, the easier it is for the abrasive grains to run up the slope of the convex portion and reach the polished surface, and the polishing rate tends to be further improved. Further, the smaller the average particle size of the abrasive grains, the more the generation of scratches on the work surface tends to be suppressed.

The average particle size of the free abrasive grains is preferably 1.35 times or more, more preferably 1.5 times or more, still more preferably 1.65 times or more the surface roughness Rz. When the free abrasive grains and the surface roughness Rz satisfy the above relationship, the free abrasive grains that have reached the upper surface of the convex portion tend to stay easily without being buried in the grooves on the polished surface.

Examples of the dispersion medium include water and an organic solvent, and an organic solvent is 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. As the type of organic solvent, commercially available organic solvents such as aliphatic and aromatic, cyclic hydrocarbons, esters, ethers, amines, amides, and ketones can be appropriately selected according to the resin and workability. The solvent may be used alone or in combination of two or more. Further, the solvent may contain other additives, if necessary. Examples of such additives include polar compounds, and specific examples thereof include nonionic surfactants, anionic surfactants, carboxylic acid esters, carboxylic acid amides and carboxylic acids. Further, various silicones and inorganic fine powders can be added as a defoaming agent, a dispersant, a leveling agent, and a viscosity improving material.

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

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. The present invention is not limited to the following examples.

[Effective polishing area]
A pressure-sensitive paper coloring liquid is applied to the polishing surface of the polishing pad, and the polishing surface (resin portion surface) of the polishing pad coated with the color-developing liquid is superposed on the pressing plate 4 for measuring the effective polishing area and the pressure-sensitive paper 5. A transfer pressure corresponding to a polishing pressure of 500 gf / cm ² was applied by a roller having a sufficiently large area to the uneven pattern, and the convex pattern was transferred to the pressure sensitive paper. Moreover, the average height t of the convex portion at the time of pressurization was measured. Then, the polishing pad and the pressure-sensitive paper were separated from each other, and the area of the polished surface transferred onto the pressure-sensitive paper was measured. The area of the transferred polished surface per unit area (1 cm ² ) of the pressure-sensitive paper surface was defined as the effective polishing area of the polishing pad.

For Examples 1 to 3 shown below, after evaluating the effective polishing area (cm ² ) of the polishing pad before dressing, the dressing process is performed under the dressing conditions shown below, and the polishing pad of the polishing pad after dressing is polished. The effective area (cm ² ) was evaluated. In Examples 4 to 5 and Comparative Examples 1 to 3 shown below, only the effective polishing area (cm ² ) of the polishing pad before dressing was evaluated.

[Average angle θ]
From the binarized convex part patterns obtained by measuring the effective polishing area, three convex parts are arbitrarily extracted, the circle-equivalent diameter of the convex part is obtained, and the obtained circle-equivalent diameter is weighted and averaged. The average circle-equivalent diameter M1 of the upper surface of the convex portion was calculated. At this time, the average distance between the base material 12 and the pressure-sensitive paper 5 was measured, and the average height t was also calculated. Furthermore, the surface of the polishing pad was photographed with a laser microscope (LASER MICROSCOPE VH-5500 manufactured by KEYENCE), the contour of the bottom surface of the convex portion was identified from the obtained image, and the average of the bottom surface of the convex portion from the specified contour. The diameter equivalent to a circle was calculated. Finally, θ was calculated from the value of tan θ calculated by the following equation (1).
tan θ = t / ((L1-M1) / 2) ... (1)
t: Average height of the convex portion when a polishing pressure of 500 g / cm ² is applied to the convex portion L1: Average circle-equivalent diameter of the bottom surface of the convex portion M1: Convex when a polishing pressure of 500 g / cm ² is applied to the convex portion Average circle equivalent diameter of the upper surface of the part

[Surface roughness Rz of polished surface]
According to JIS B0633: 2001 (ISO4288: 1996), the surface roughness Rz of the polished surface was measured using a stylus type surface roughness meter (Taylor Hobson Foam Talisurf PGI1240). The surface of the convex portion of the object to be measured was installed so that the measuring needle passed in the measuring direction in which the parameter (Rz) in the height direction was maximized from the center of the apex to the center of the adjacent apex, and the measurement was performed by a stylus at 20.1 mm. Select the top of the convex surface from the measured cross-sectional image, cut off at 0.25 mm when Rz is 0.5 mm or less, cut off at 0.8 mm when Rz exceeds 0.5 mm, and convex. The surface roughness Rz was determined by using the length of the top of the surface of the portion as the evaluation length.

For Examples 1 to 3 shown below, the surface roughness Rz of the polishing pad before dressing was evaluated, and then the dressing process was performed under the dressing conditions shown below, and the surface roughness Rz of the polishing pad after dressing was evaluated. .. In Examples 4 to 5 and Comparative Examples 1 to 3 shown below, only the surface roughness Rz of the polishing pad before dressing was evaluated.

[Polishing test]
A polishing pad was placed at a predetermined position of the polishing device via 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 Examples 1 to 3 shown below, in the polishing test, the polishing pad was first dressed under the conditions shown in the following dressing conditions, and the polishing was performed under the conditions shown in the following polishing conditions. ..
In Examples 4 to 5 and Comparative Examples 1 to 3 shown below, polishing was carried out under the conditions shown in the following polishing conditions without performing the following dressing process.
(Dress condition)
Dress count: # 270 (equivalent to 65 μm)
Dress rotation speed: 70 rpm
Dress pressure: 311gf / cm ²
Dress time: 5min
(Polishing conditions)
Surface plate rotation speed: 100 rpm
Surface pressure: 495 gf / cm ²
Lubricant High Viscosity: V600
Polishing time:
Polishing rate: 20min
Continuous polishing: Up to 15 hours or more Abrasive grain: Polycrystalline diamond (abrasive particle size 7 μm)

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

(Product life)
The product life was evaluated in the following three stages as the time for the polishing rate to decrease to 60% when the initial polishing rate was 100%.
◯: Cleared over 15 hours.
Δ: Stayed for 7 to 15 hours.
X: Less than 7 hours.

[Example 1]
51 parts by mass of epoxy resin (manufactured by DIC, trade name "EPICLON850-S", epoxy equivalent: 183 to 193 g / eq) and tetrahydrophthalic anhydride (manufactured by DIC, trade name "EPICLONB-570-H", acid) Anhydrous equivalent: 166 g / eq) 45 parts by mass, fumed silica (manufactured by Nippon Aerosil Co., Ltd .: Aerosil RY200S) by 3 parts by mass, and imidazole (2E4MZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.) by 1 part by mass. A curable composition was prepared. It should be noted that the polishing effect of the fumed silica as abrasive grains is not present, or even if it is present, it is extremely low.

On the polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name Cosmo Shine A4300 250 μm), which is the base material, the dot-shaped protrusions are regularly arranged in the uneven pattern shown in FIG. 1 by screen printing. The curable composition was applied using a screen mask having a dot diameter of 2 mm and a close contact distance between adjacent dots of 0.5 mm.

Then, by heating to 130 degrees, the curable composition was cured and a resin portion was formed. Finally, a double-sided tape (manufactured by 3M, product name film base material double-sided adhesive tape 442JS) was attached as an adhesive layer on the side opposite to the resin portion of the base material to obtain the polishing pad of Example 1.

[Example 2]
The polishing pad of Example 2 was obtained by the same method as in Example 1 except that a screen mask having a dot diameter of 3 mm and a close contact distance between adjacent dots of 0.5 mm was used.

[Example 3]
The polishing pad of Example 3 was obtained by the same method as in Example 1 except that a screen mask having a dot diameter of 4 mm and a close contact distance between adjacent dots of 0.5 mm was used.

[Example 4]
100 parts by mass of UV coating agent (Teikoku Printing Inks, product name UV BOP), 20 parts by mass of photocurable monomer (Shin Nakamura Chemical Industry Co., Ltd., product name TMM-360), and photocurable monomer (new) A curable composition was prepared by mixing with 10 parts by mass of Nakamura Chemical Industry Co., Ltd., product name LMA).

On the polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name Cosmo Shine A4300 250 μm), which is the base material, the dot-shaped protrusions are regularly arranged in the uneven pattern shown in FIG. 1 by screen printing. The curable composition was applied using a screen mask having a dot diameter of 2 mm and a close contact distance between adjacent dots of 0.5 mm.

Then, the curable composition was cured by UV irradiation with a UV device (manufactured by Eye Graphics Co., Ltd., product name: metal halide lamp 120 W / cm) to form a resin portion. Finally, a double-sided tape (manufactured by 3M, product name film base material double-sided adhesive tape 442JS) was attached as an adhesive layer on the side opposite to the resin portion of the base material to obtain the polishing pad of Example 4.

[Example 5]
The polishing pad of Example 5 was obtained by the same method as in Example 4 except that a screen mask having a dot diameter of 1 mm and a closest contact distance between adjacent dots of 1 mm was used.

[Comparative Example 1]
The polishing pad of Comparative Example 1 was obtained by the same method as in Example 4 except that a screen mask having a dot diameter of 1 mm and a closest contact distance between adjacent dots of 2 mm was used.

[Comparative Example 2]
The polishing pad of Comparative Example 2 was obtained by the same method as in Example 4 except that a screen mask having a dot diameter of 0.5 mm and a closest contact distance between adjacent dots of 0.33 mm was used.

[Comparative Example 3]
A mold having a truncated cone-shaped recess having a diameter of 8 mm, a close contact distance between adjacent recesses of 3 mm, a height of 1.6 mm, and a taper angle of 83 degrees was prepared.
Next, 100 parts by mass of UV coating agent (manufactured by Teikoku Printing Co., Ltd., product name UV BOP), 20 parts by mass of photocurable monomer (manufactured by Shin Nakamura Chemical Industry Co., Ltd., product name TMM-360), and photocurability. A curable composition was prepared by mixing with 10 parts by mass of a monomer (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., product name LMA).

Next, the curable composition is cast into the concave portion of the mold, and a polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., product name Cosmo Shine A4300 250 μm) as a base material is applied on the mold while applying pressure with a roller. It was laid so that the curable composition and the base film were adhered to each other. Further, by irradiating UV through the base film with a UV device (manufactured by Eye Graphics Co., Ltd., product name: metal halide lamp 120 W / cm), the curable composition is cured and the base film is released from the mold. A resin part was formed. Finally, a double-sided tape (manufactured by 3M, product name film base material double-sided adhesive tape 442JS) was attached as an adhesive layer on the side opposite to the resin portion of the base material to obtain a polishing pad of Comparative Example 3.

（）:カッコ内はドレス後

(): After dressing in parentheses

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

10 ... Polishing pad, 11 ... Resin part, 11a ... Convex part, 11b ... Cross section, 12 ... Base material, 13 ... Adhesive layer, 4 ... Pressing plate, 5 ... Pressure sensitive paper, 6 ... Polished surface

Claims (10)

A polishing pad including a base material and a resin portion arranged on the base material.
The resin portion forms a concavo-convex pattern alone or together with the base material.
The uneven pattern is a pattern in which a plurality of convex portions having a polished surface are arranged.
The total area of the polished surface when the polishing pressure of 500 g / cm ² is applied to the convex portion is 0.05 to 0.8 cm ² per unit area (1 cm ² ) of the substrate surface.
The surface roughness Rz is 0.75 or less based on the average particle size of 1 to 18 μm of the free abrasive grains used for polishing as a reference 1.0.
The θ satisfying the following equation (1) is 5 to 60 °.
tan θ = t / ((L1-M1) / 2) ... (1)
t: Average height of the convex portion when a polishing pressure of 500 g / cm ² is applied to the convex portion L1: Average circle-equivalent diameter of the bottom surface of the convex portion M1: Polishing pressure of 500 g / cm ² is applied to the convex portion. A polishing pad having a diameter equivalent to an average circle on the upper surface of the convex portion when the protrusion is formed. The average height t of the convex portion is 0.06 to 1 mm.
The polishing pad according to claim 1. The average circle-equivalent diameter L1 of the convex portion is 1 to 5 mm.
The polishing pad according to claim 1 or 2. The closest contact distance L2 of the adjacent convex portions is 0.1 to 3 mm.
The polishing pad according to any one of claims 1 to 3. The resin portion contains at least one selected from the group consisting of an epoxy resin, an acrylic resin, a polyester resin, an unsaturated polyester resin, a polyamide resin, and a polyurethane resin.
The polishing pad according to any one of claims 1 to 4. An adhesive layer is further provided on the side of the base material opposite to the resin portion.
The polishing pad according to any one of claims 1 to 5. The polished surface is substantially free of fixed abrasive grains.
The polishing pad according to any one of claims 1 to 6. The method for manufacturing a polishing pad according to any one of claims 1 to 7.
The present invention comprises a step of forming a resin portion having a concavo-convex pattern in which a plurality of convex portions having a polished surface are arranged on a substrate by a screen printing method, an exposure plate making method, or a molding method.
How to make 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 7 in the presence of free abrasive grains.
Manufacturing method of polished products. The average particle size of the free abrasive grains is 0.25 to 18 μm.
The method for manufacturing a polished product according to claim 9.

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