JP2015100855A - Method for production of abrasive pad, and abrasive pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abrasive pad production method capable of maintaining the opening of oblong cells inside a groove and capable of preventing hardening of the groove inside even when forming a sufficiently deep groove on an abrasive pad produced by a wet type film formation method, and to provide the abrasive pad.SOLUTION: There is provided a method of producing an abrasive pad on the surface of which grooves 21 are formed by a wet type film formation method. The method comprises the processes of: forming an abrasive sheet having multiple oblong cells 23 inside by the wet type film formation method; opening the tear type bubbles 23 on the abrasive surface of the abrasive sheet by grinding or slicing the face on a side where the bubble of the abrasive sheet is reduced in diameter; disposing a protective sheet for preventing temperature elevation on the opened abrasive surface; and forming the groove on the protective sheet-disposed surface by pressing a heated die having a prescribed-shape protrusion.

Description

  The present invention relates to a method for manufacturing a polishing pad and a polishing pad, and more particularly to a polishing pad used in a chemical mechanical polishing method and a method for manufacturing the same.

  Conventionally, a chemical mechanical polishing method (CMP method) has been used as a method for polishing and flattening the surface of an object to be polished such as a semiconductor wafer, a liquid crystal display substrate, a photomask substrate, a magnetic disk substrate or the like. ing. When polishing an object to be polished using the CMP method, the polishing pad is pressed against the object to be polished, and the polishing pad and the object to be polished are rotated while supplying the polishing slurry between them. The polishing slurry flows from the center side toward the outside by centrifugal force accompanying the rotation of the polishing pad, and is finally discharged to the outside of the polishing pad.

  A wet film forming method is known as a method for manufacturing such a polishing pad. When manufacturing a polishing sheet using a wet film forming method, a polyurethane resin solution containing dimethylformamide (DMF) is applied on a flat substrate, and the substrate on which the polyurethane resin solution is applied is washed with water. Immerse in the coagulation liquid as the main component. When the substrate coated with the polyurethane resin solution is immersed in the coagulation liquid, first, the surface of the polyurethane resin solution in contact with the coagulation liquid is coagulated to form a skin layer. When the skin layer is formed, DMF in the resin solution diffuses into the coagulating liquid through the skin layer film due to the osmotic pressure of DMF. At substantially the same time, the coagulation liquid flows into the resin solution through the skin layer film, and the coagulation of the resin solution starts gradually from the vicinity of the skin layer. And since the skin layer forms a hydrophobic field in the resin solution, the coagulating liquid gathers in the direction away from the skin layer, and the resin density at the position away from the skin layer decreases, while the resin density near the skin layer increases. . Thereby, a vertically long space extending substantially perpendicular to the skin layer is formed in the resin. Then, the substrate coated with the polyurethane resin solution is immersed in the coagulation liquid (coagulation regeneration), and the DMF in the remaining polyurethane resin solution is removed. Next, drying is performed by evaporating the water contained in the urethane resin using a dryer. And if the water | moisture content in the space of resin evaporates, many vertically long bubbles are formed in the resin in the thickness direction. Due to the formation of the bubbles, when the object to be polished is polished, a cushioning property can be exerted on the object to be polished, an excessive increase in pressure due to polishing scraps can be suppressed, and scratches can be suppressed.

  By the way, in recent years, the polishing slurry is evenly and sufficiently spread over the surface of the object to be polished, thereby flattening the object to be polished uniformly and with high accuracy, suppressing consumption of expensive polishing slurry, and causing scratches. In order to achieve efficient discharge of the resulting polishing debris, it is a common practice to control the flow of polishing slurry by forming grooves of various shapes on the surface of the polishing pad. By controlling the flow of the polishing slurry in the groove, the polishing slurry can be evenly and sufficiently distributed over the surface of the object to be polished, consumption of the polishing slurry can be suppressed, and polishing debris can be efficiently removed from the polishing surface and the surface to be polished. It can be discharged from between the polished objects. As such a technique, for example, one described in Patent Document 1 is known.

JP-A-8-197434

  As a technique for forming the groove described above, a method of forming a groove on the surface with a cutting tool and embossing in which a mold having a convex portion complementary to the groove is pressed while applying heat to the polishing pad are known. . When forming a groove by cutting, prepare a polishing sheet having vertically elongated bubbles in the thickness direction, use the surface on which the skin layer is formed as a polishing surface, and subject the polishing surface to grinding or slicing to create bubbles Open. Then, grooves are formed on the polished surface in a shape designed by a cutting tool. When grooves are formed by embossing, prepare a polishing sheet having vertically elongated bubbles in the thickness direction, use the surface on which the skin layer is formed as a polishing surface, and subject the polishing surface to grinding or slicing to create bubbles. Open. Then, the heated mold is pressed against the polishing surface with the polishing pad opened, the polishing surface of the polishing pad in contact with the mold is melted, deformed into a shape complementary to the mold, and then cooled to room temperature again. As a result, the polishing surface of the polishing pad is deformed to form a groove.

  However, when a groove is formed using a cutting tool on an abrasive sheet made by a wet film-forming method, chips and chips are always generated inside the groove formed by the cutting tool, and this is released during polishing. And cause defects such as scratches. On the other hand, when the groove is formed using embossing, the opening on the polished surface against which the mold is pressed is blocked or reduced in diameter by welding. This makes it easier for the polishing slurry in the groove to be discharged, causing problems such as wasting the polishing slurry, which is discharged without being used for polishing, or becoming harder due to higher density due to blockage and reduced diameter. -Decrease in cushioning properties, which could cause scratches. By reducing the processing temperature during embossing, clogging and shrinkage can be suppressed and the waste of polishing slurry and scratching associated with this can be reduced. In this case, grooves with sufficient depth can be formed. In addition, the ability to spread the polishing slurry over the polishing surface was poor, which was not preferable.

  Therefore, the present invention can maintain the opening of bubbles inside the groove even when a groove having a sufficient depth is formed on a polishing pad made by a wet film formation method, and suppresses the hardening in the groove. An object of the present invention is to provide a method for manufacturing a polishing pad and a polishing pad.

  In order to solve the above-mentioned problems, the present invention is a method of manufacturing a polishing pad made by using a wet film formation method and having a groove formed on the polishing surface. Forming a polishing sheet having a large number of vertically elongated bubbles, opening the bubbles on the polishing surface of the polishing sheet by grinding or slicing the surface of the polishing sheet on which the skin layer is formed, and A step of disposing a protective sheet for suppressing temperature rise on the opened polished surface; and a surface having the predetermined shape on the surface on which the protective sheet is disposed, and pressing the heated mold to form grooves. And a forming step.

  According to the present invention configured as described above, before embossing with a mold, embossing is performed by applying a grinding process or a slicing process to cover a surface on which bubbles are opened, and a sheet that suppresses temperature rise. Sometimes, it is possible to suppress an increase in the temperature of the polished surface opened by the abrasive sheet subjected to grinding or slicing. And by covering such a protective sheet and suppressing the temperature rise of the polishing surface, the heated mold can be pressed to suppress the temperature rise of the polishing surface during thermal processing. And by suppressing the temperature rise of the polishing surface, it is possible to prevent the periphery of the opening of the opened bubble from rapidly melting and closing the opening.

  In the present invention, preferably, the surface of the protective sheet to be attached to the polishing sheet is subjected to a mold release treatment.

  According to the present invention configured as described above, the protective sheet can be prevented from sticking to the polishing sheet when the mold is pressed to form the groove.

  In order to solve the above-described problems, the present invention provides a polishing pad manufactured by a wet film formation method and having grooves formed on the polishing surface, and a plurality of vertically long bubbles in the thickness direction inside the polishing pad. And the bubbles are open on the surface of the groove, and the average opening diameter is 5 to 20 μm.

  According to the present invention configured as described above, since the opening in the groove is maintained and formed, there are unevenness derived from the opening in the groove, and the waste of the polishing slurry can be suppressed by the unevenness. Thereby, the polishing slurry is effectively used for polishing. Furthermore, in the present invention, since the heat history is small and the hardening in the groove can be suppressed, it contributes to the reduction of scratches.

  As described above, according to the present invention, even when a groove having a sufficient depth is formed on a polishing pad manufactured by a wet film formation method, the groove has an opening inside the groove, and the unevenness derived from the opening causes the polishing slurry to be formed. Waste can be suppressed. Thereby, the polishing slurry is effectively used for polishing. Moreover, since hardening in a groove | channel can be suppressed, it contributes to a scratch reduction.

1 is a cross-sectional view showing a polishing apparatus to which a polishing pad according to an embodiment of the present invention is applied. It is a top view of the polishing pad by the embodiment of the present invention. It is sectional drawing to which the principal part of the polishing pad by embodiment of this invention was expanded. It is sectional drawing to which the principal part of the polishing pad by embodiment of this invention was expanded, and is a figure for demonstrating the manufacturing method of a polishing pad.

  Hereinafter, a polishing pad and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a polishing apparatus to which a polishing pad according to an embodiment of the present invention is applied.

  First, as shown in FIG. 1, a polishing apparatus 1 is for flattening a surface of an object to be polished 3 by a CMP method. The polishing apparatus 1 includes a polishing surface plate 5 that rotates about a rotation axis, a polishing pad 7 that is fixed to the upper surface of the polishing surface plate 5, and a holding surface plate 9 that holds the workpiece 3. . A polishing pad 7 is set on one surface of the polishing surface plate 5, and the workpiece 3 is disposed on the polishing pad 7.

  Such a polishing apparatus 1 rotates the polishing surface plate 5 around the shaft 15 and rotates the holding surface plate 9 around the center while supplying the polishing slurry from the polishing slurry supply device 11 to the polishing surface 13 of the polishing pad 7. By doing so, the surface of the workpiece 3 held by the holding surface plate 9 that is in contact with the polishing surface 13 of the polishing pad 7 is flattened.

  The polishing surface plate 5 is made of metal and has a disk shape. One surface of the polishing surface plate 5 constitutes an affixing surface to which the polishing pad 7 is affixed, and this affixing surface is substantially flat. The polishing surface plate 5 is fixed to a single shaft 15 passing through the center thereof, and rotates around the shaft 15 by rotating the shaft 15.

  The holding surface plate 9 has a diameter larger than that of the workpiece 3 and is configured by attaching a holding pad 17 made of, for example, soft plastic to a hard surface plate. During polishing, a predetermined polishing pressure is applied from the holding surface plate 9 to the workpiece 3.

  Further, the polishing apparatus 1 includes a dresser 19 for conspicuous the polishing surface 13 of the polishing pad 7. The dresser 19 is arranged at a position to be pointed with the holding surface plate 9 with respect to the center of the polishing pad 7, and sharpens the surface of the polishing pad 7.

  FIG. 2 is a plan view of the polishing pad. The polishing pad 7 is made of polyurethane foam formed by a wet film formation method, and has a large number of vertically long bubbles in the thickness direction. Further, the polishing pad 7 includes a large number of grooves 21 formed in the polishing surface 13. The groove 21 is formed by recessing the polishing surface 13, and is used to uniformly distribute the polishing slurry on the polishing surface and the surface to be polished, thereby increasing the circulation of the polishing slurry and suppressing consumption. is there. The grooves 21 are arranged in a lattice pattern on the polishing surface 13. In the present embodiment, the polishing pad having the grid-like grooves 21 will be described in detail. However, the groove 21 may have any shape as long as it can be formed by embossing. It may extend radially from the center or spirally.

  FIG. 3 is an enlarged cross-sectional view of a main part of the polishing pad. A large number of bubbles 23 are formed inside the polishing pad 7, and each has a vertically long bubble that hangs down from the polishing surface 13. Each bubble 23 is opened to the polishing surface 13 and the surface of the groove 21 by removing the skin layer by buffing. Since the opening of the polished surface remains on the groove side surface and the groove bottom after embossing, the number of bubbles per unit area in the groove is the same as the number of bubbles per unit area of the polished surface. ing.

  The average opening diameter in the groove is preferably about 5 to 20 μm. If it is 5 μm or less, the polishing slurry flows out smoothly, so that the polishing slurry is wasted. In addition, if the diameter is 20 μm or more, the opening diameter is too large, so that large polishing debris generated in the polishing process is accommodated in the groove, and the stored polishing debris is released as the polishing process continues. , Will cause scratches. The depth of the groove is preferably about 40% to 60% of the thickness of the polishing sheet. If it is 40% or less, the groove volume is small, and the effect of spreading the slurry uniformly on the polished surface is poor. On the other hand, if it is 60% or more, the thermal history increases and the hardening in the groove progresses. It becomes a factor of.

  Moreover, the double-sided tape (not shown) for mounting | wearing a polishing pad with the polishing pad is bonded to the polishing pad on the surface opposite to the polishing surface of the resin sheet. The double-sided tape has, for example, a base material of a flexible film such as a film made of polyethylene terephthalate (hereinafter abbreviated as PET). Are respectively formed. In the double-sided tape, a pressure-sensitive adhesive layer on one side of a substrate and a resin sheet are bonded together, and the pressure-sensitive adhesive layer on the other side (the side opposite to the resin sheet) is covered with release paper. In addition, the base material of this double-sided tape also serves as the base material of the polishing pad.

  Next, the manufacturing method of the polishing pad according to the present embodiment will be described in detail. When manufacturing the polishing pad 7, first, a flat polishing sheet is manufactured by a wet film forming method.

  When manufacturing a polishing sheet using a wet film forming method, a polyurethane resin solution having a viscosity of 3 to 50 Pa · s and containing dimethylformamide (DMF) on a flat substrate has a thickness of 0.5 to 1.5 mm. Apply to the extent. And the base | substrate with which the polyurethane resin solution was apply | coated is immersed in the coagulation liquid which has water as a main component. When the substrate coated with the polyurethane resin solution is immersed in the coagulation liquid, first, the surface of the polyurethane resin solution in contact with the coagulation liquid is coagulated to form a skin layer. When the skin layer is formed, DMF in the resin solution diffuses into the coagulating liquid through the skin layer film due to the osmotic pressure of DMF. At substantially the same time, the coagulation liquid penetrates into the resin solution through the skin layer, and the resin solution gradually begins to coagulate from the vicinity of the skin layer. And since the skin layer forms a hydrophobic field in the resin solution, the coagulating liquid gathers in the direction away from the skin layer, and the resin density at the position away from the skin layer decreases, while the resin density near the skin layer increases. . Thereby, a vertically long space extending substantially perpendicular to the skin layer is formed in the resin. Then, the substrate coated with the polyurethane resin solution is immersed in the coagulation liquid (coagulation regeneration), and the DMF in the remaining polyurethane resin solution is removed. Next, drying is performed by evaporating moisture contained in the urethane resin using a dryer. And if the water | moisture content in the space of resin evaporates, a vertically long bubble will be formed in resin in many thickness directions. Thus, a polishing sheet having a large number of bubbles can be made using a wet film formation method.

  Next, the skin layer of the polishing sheet is buffed to remove the skin layer, and bubbles on the surface where the skin layer was present are opened. Subsequently, a double-sided tape is bonded to the side opposite to the opening surface. At this time, the pressure-sensitive adhesive layer on one side of the double-sided tape is bonded to the opposite side of the opening surface of the polishing sheet. Next, bubbles form grooves 21 on the opening surface, cut into shapes and sizes such as circles and squares, and then inspected to confirm that there are no scratches, dirt, foreign matter, etc., and polishing Complete the pad.

  FIG. 4 is an enlarged cross-sectional view of a main part of the polishing pad, and is a diagram for explaining a method for manufacturing the polishing pad.

  When forming the groove 21, as shown in FIG. 4, first, protection for suppressing the temperature rise of the surface on which the groove 21 is to be formed when the mold is applied to the surface on which the groove 21 is to be formed. Cover the sheet 25. As such a protective sheet, it is preferable to use a material that has a certain degree of thermal resistance, does not stick to the polishing pad when heated, and has a cushioning property that absorbs an impact when pressed against a mold. . In addition, as for the thickness of a protection sheet, 10-300 micrometers is preferable. Moreover, it is preferable that the protective sheet surface on the side in contact with the polishing sheet is subjected to a grinding process or a mold release treatment with a mold release agent so that the protective sheet does not stick to the polishing pad when the mold is pressed. As a specific example of the protective sheet, for example, a flexible polyurethane sheet is suitable, and the surface of the flexible polyurethane sheet that is opened by buffing is preferably used facing the polishing sheet.

  Next, a mold 27 having a convex portion complementary to the groove to be formed is prepared, and the abrasive sheet is thermally compressed from above the protective sheet 25 by the mold 27. When the mold 27 is pressed against the polishing sheet, the surface of the polishing sheet sinks into a shape complementary to the mold 27. At this time, by providing the protective sheet 25 between the mold 27 and the polishing sheet, the heat of the mold 27 is gently transmitted to the polishing sheet, and the temperature rise of the polishing sheet is moderated. Then, by moderately increasing the temperature of the polishing sheet during embossing, melting of the resin around the opening of the bubble is inhibited, and the bubble shape can be prevented from collapsing. By embossing so that the shape of the resin around the opening of the bubble does not collapse, the groove 21 can be formed while maintaining the opening of the bubble in the groove formed by the embossing.

  As described above, by using the polishing pad 7 in which bubbles are opened on the surface of the groove 21, there are unevenness derived from the opening in the groove, and waste of the polishing slurry can be suppressed by the unevenness. Thereby, the polishing slurry is effectively used for polishing. Furthermore, in the present invention, since the heat history is small and the hardening in the groove can be suppressed, it contributes to the reduction of scratches.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
First, with respect to 100 parts by mass of a 30% DMF solution of an ester-based polyurethane resin having a 100% modulus of 8.5 MPa, which is a raw material resin as a matrix resin, 60 parts by mass of DMF for viscosity adjustment and 15 carbon black as a pigment are used. 16 parts by mass of a DMF dispersion containing 5% by mass was mixed and stirred to prepare a resin solution. Next, a PET film was prepared as a substrate, and the resin solution was applied thereto using a knife coater to obtain a coating film having a thickness of 1.0 mm.

  Subsequently, the obtained coating film was immersed in a coagulation bath made of water as a coagulation liquid together with the base material, and the resin was coagulated and regenerated to obtain a precursor sheet. The precursor sheet was taken out from the coagulation bath, and the precursor sheet was immersed in a room temperature cleaning solution (desolvent bath) made of water, and DMF as a solvent was removed to obtain a resin sheet. Thereafter, the surface of the resin sheet (the surface that was not in contact with the substrate) was buffed to a thickness of 0.8 mm. The obtained resin sheet having a thickness of 0.8 mm and a double-sided tape having a PET base material were bonded together.

  Next, a protective sheet was placed on the surface of the resin sheet that had been buffed. A soft polyurethane sheet (thickness: 20 μm) whose surface was opened by buffing was used as a protective sheet, and the opening surface was covered with the polishing sheet. Next, this laminate was embossed at a processing pressure of 4.5 MPa, a processing temperature of 145 ° C., and a processing time of 60 seconds. After embossing, the protective sheet was peeled from the laminate to obtain a polishing pad.

(Measurement of average opening diameter)
The opening diameter of the obtained polishing pad was measured. The measurement method was as follows. First, the groove inner surface and the polishing surface of the polishing pad were photographed at a magnification of 100 times with an optical microscope “VHX-550, manufactured by KEYENCE”. Subsequently, the photographed image was taken into image processing software “NanoHunter NS2K-Pro, manufactured by Nanosystem Corporation”, and binarized to obtain a dark and light image. For a shaded image, a portion showing a hole (in this case, a dark portion) was set as an opening, and the concentration range (threshold) of the opening was set so that an image that could be recognized as an opening was captured. Subsequently, the opening area was calculated by integrating the openings, and the equivalent circle diameter and the average value (average opening diameter) were calculated from the opening area.

(Measurement of thickness and groove depth)
Subsequently, the thickness of the polishing pad and the groove depth were measured. As a measuring method, first, a cross section of the polishing pad was photographed at a magnification of 100 times using an optical microscope “VHX-550, manufactured by KEYENCE”. Subsequently, the captured image was taken into an image processing software “NanoHunter NS2K-Pro, manufactured by Nano System Co., Ltd.”, and the thickness and groove depth were measured by a distance measurement process between two lines. The thickness was measured at three points selected at random with respect to the thickness of the resin sheet on the polished surface part that directly contributes to the polishing process, and the arithmetic average was taken as the thickness of the product of the present invention. Similarly, for the groove depth, the thickness of the resin sheet in the groove portion selected at random was measured at three points, and the groove depth was determined from the difference between the arithmetic average and the thickness of the polished surface portion.

(Polishing test)
A polishing test was performed using the polishing pad, and the polishing uniformity and the presence or absence of defects were evaluated. The polishing conditions were as follows. As an object to be polished, a substrate (uniformity (CV%) of 13%) in which an insulating film was formed to a thickness of 1 μm by CVD of tetraethoxysilane on a 12-inch silicon wafer was used.
(Polishing conditions)
-Polishing machine: Product name “F-REX300” manufactured by Ebara Corporation
Polishing head: manufactured by Ebara Manufacturing Co., Ltd., model number “GII”
Polishing slurry: Planar, model number “ER8176C”, 2-fold dilution, hydrogen peroxide concentration 0.8 mass%
・ Polishing pad diameter: 740mmφ
・ Dresser: 3M diamond dresser, model number “A188”
・ Pad break-in conditions: 9 N × 30 minutes, dresser rotation speed 54 rpm, surface plate rotation speed 80 rpm, ultrapure water supply amount 200 mL / min ・ Conditioning: Ex-situ, 30 N, 4 scans, 16 seconds ・ Polishing conditions: constant Plate rotation speed 70 rpm, polishing head rotation speed 71 rpm, polishing slurry flow rate 200 mL / min, polishing time 1 minute (per wafer), polishing pressure 2.5 psi (1.7 × 10 ⁴ Pa)

(Polishing uniformity)
The polishing uniformity of the object to be polished was evaluated by the variation (standard deviation ÷ average value) (%) of (thickness) obtained from the thickness measurement results of 121 locations on the insulating film of the substrate before and after polishing.
The thickness was measured in the DBS mode of an optical film thickness chamber measuring device (ASES-F5x, manufactured by KLA Tencor). The case where the thickness variation was less than 3% was evaluated as “◯”, and the case where 3% or more was confirmed was evaluated as “x”.

(scratch)
For scratches, 25 substrates are repeatedly and sequentially polished three times, and the high sensitivity of the patternless wafer surface inspection apparatus (KLA Tencor), Surfscan SP1DL) on the 21st to 25th substrates after polishing. The measurement was performed in the measurement mode, and the number of scratches on the substrate surface was observed. As a result of observation, a case where only less than 50 scratches were confirmed was evaluated as “◯”, and a case where 50 or more scratches were confirmed was evaluated as “x”.
The results are shown in Table 1.

(Example 2)
A polishing pad was obtained in the same manner as in Example 1 except that the processing time was changed to 120 seconds. The obtained polishing pad was subjected to various measurements and polishing tests in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
A polishing pad was obtained in the same manner as in Example 1 except that the protective sheet was not used. The obtained polishing pad was subjected to various measurements and polishing tests in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
A polishing pad was obtained in the same manner as in Example 2 except that the holding sheet was not used. The obtained polishing pad was subjected to various measurements and polishing tests in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3)
A polishing pad was obtained in the same manner as in Comparative Example 2 except that the processing temperature was changed to 60 degrees. The obtained polishing pad was subjected to various measurements and polishing tests in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
A polishing pad was obtained in the same manner as in Comparative Example 2 except that the processing temperature was changed to 100 degrees. The obtained polishing pad was subjected to various measurements and polishing tests in the same manner as in Example 1. The results are shown in Table 1.

(result)
As shown in the table, in Example 1 and Example 2 in which embossing was performed using a protective sheet, both the polishing uniformity and scratch results were good. On the other hand, in Comparative Examples 1 and 2 in which embossing was performed without using a protective sheet, good results were not obtained in both polishing uniformity and scratch. The reason for the deterioration of the polishing uniformity is considered to be that the opening in the groove is very small and the inside of the groove is smooth, so that the polishing slurry is easily discharged during polishing, and there is insufficient polishing slurry on the entire polishing surface. . The other cause of the scratch is considered to be that the protective sheet was not used, so that heat was directly applied to the polished surface from the mold, the polished surface was melted, and the hardening in the grooves progressed. In Comparative Examples 3 and 4 in which embossing was performed at a lower temperature than Example 2 without using a protective sheet, the polishing uniformity deteriorated. This is probably because the groove could not be formed deeply at low temperature, and the ability to spread the polishing slurry over the entire polishing surface was low.

DESCRIPTION OF SYMBOLS 1 Polishing apparatus 3 Object 7 Polishing pad 13 Polishing surface 21 Groove 23 Bubble 25 Protective sheet

Claims (4)

A method of manufacturing a polishing pad manufactured by a wet film formation method and having a groove formed on a polishing surface,
Forming a polishing sheet having a large number of vertically long bubbles in the thickness direction by a wet film formation method;
The surface of the polishing sheet on which the skin layer is formed is a polishing surface, the polishing surface side is ground or sliced to open the bubbles, and
A step of arranging a protective sheet for suppressing temperature rise on the opened polished surface;
And a step of forming a groove by pressing a heated mold on the surface on which the protective sheet is disposed and pressing a heated mold.   The manufacturing method of the polishing pad according to claim 1, wherein a surface of the protective sheet attached to the polishing sheet is subjected to a mold release process. A polishing pad manufactured by a wet film formation method and having a groove formed on the polishing surface,
A polishing pad having a large number of vertically long bubbles in the thickness direction inside the polishing pad, an opening on the surface of the groove, and an average opening diameter of 5 μm to 20 μm.   The polishing pad according to claim 3, wherein the groove depth is in the range of 40% to 60% with respect to the thickness of the polishing sheet.

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