Manufacturing method for polishing pads

Abstract

To provide a method for manufacturing a polishing pad with an endpoint detection window (window member) that exhibits excellent adhesion between the back surface of the window member and the adhesive surface of the second sheet. [Solution] A polishing pad comprising a first sheet having a first through-hole, a second sheet having a second through-hole, and a window member, wherein the first sheet has a polishing surface for polishing an object to be polished, the second sheet is bonded to the surface of the first sheet opposite to the polishing surface, the outer periphery of the second through-hole is formed to cover the outer periphery of the first through-hole, and the window member is positioned inside the first through-hole and on the second sheet such that the uppermost part of the window member is lower than the polishing surface; and a method for manufacturing a polishing pad comprising the steps of: preparing the polishing pad, and placing a spacer of a predetermined thickness on a press platen under the polishing pad around the polishing pad, and pressing the polishing pad with a press machine.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a polishing pad, and more particularly to a method for manufacturing a polishing pad for chemical mechanical polishing (CMP) having a light transmission region.

Background Art

[0002] In semiconductor manufacturing processes (particularly, planarization of an interlayer insulating film, formation of a metal plug, or formation of an embedded wiring in a multilayer wiring formation process), a chemical mechanical polishing (hereinafter referred to as "CMP") method is used. CMP is applied to semiconductor manufacturing processes (particularly, planarization of an interlayer insulating film, formation of a metal plug, formation of an embedded wiring, etc.) in a multilayer wiring formation process.

[0003] In recent years, the multilayer and high-definition of semiconductor devices have advanced rapidly, and further improvement in the yield and throughput (production volume) of semiconductor devices is required. For a polishing pad, defect-free and high planarization characteristics without dishing are desired. In order to achieve these requirements, it is necessary to detect the time when the desired surface characteristics and planar state are reached, and an optical method is widely used as a detection method because it can accurately detect. In this method, for example, a window portion having light transmissivity for polishing end point detection is formed in at least a part of a polishing layer constituting a polishing pad, light is irradiated onto a processed surface through this window portion, and the reflection state of light from the processed surface is observed to determine the polishing state. Therefore, the polishing end point can be detected in situ, and deterioration of the yield due to over-polishing can be suppressed.

[0004] As a pad having a window for end point detection, a polishing pad of a type (insertion type) in which through holes are opened in a plurality of layers and a window member is fitted into the through holes is known (Patent Documents 1 to 5). Further, as a method for manufacturing a polishing pad with a window member, a method of punching holes in an adhesive layer or a cushion layer so as to match the position of the window member of a polishing layer obtained by a method of inserting and integrating the window member at the stage of forming the polishing layer (integral type) and bonding them is known (Patent Document 6). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2004-260156 [Patent Document 2] Japanese Patent Publication No. 2021-136288 [Patent Document 3] Special Publication No. 2020-516474 [Patent Document 4] Japanese Patent Publication No. 2023-105842 [Patent Document 5] Japanese Patent Publication No. 2019-93543 [Patent Document 6] Japanese Patent Publication No. 2022-149504 [Overview of the project] [Problems that the invention aims to solve]

[0006] The manufacturing methods described in Patent Documents 1 to 5 are so-called insert-type manufacturing methods, in which the window member is adhesively fixed onto a support layer that is joined to the polishing layer. In this case, there is a problem that slurry leakage is likely to occur during the CMP process due to the gap between the polishing layer and the window member. For example, in Patent Document 1, a hole for fitting the window member is punched out in the polishing layer, double-sided tape is attached to the cushion layer, the polishing layer and the cushion layer are bonded together via the double-sided tape, and a portion of the cushion layer in the area where the window member is to be fitted is punched out to penetrate the hole and fit the window member in. However, if it is simply fitted in, air may remain between the window member and the double-sided tape, and slurry may seep into the areas that are not bonded, potentially causing the window member to peel off. To address this problem, Patent Document 3 describes preventing leakage by applying hot-melt adhesive to the back surface of the window member, and also using hot-melt adhesive for the support layer and polishing layer to heat-seal the window member and support layer. In this case, although leakage can be prevented, there is a risk that the light-transmitting portion will have two layers, reducing light transmittance, and that foreign matter may adhere to the exposed adhesive surface, further reducing light transmittance. In Patent Document 4, in order to prevent the window member from peeling off the polishing layer, the back surface of the polishing layer around the window member is ground to create a recessed flange portion, and this flange portion is bonded and fixed to the polishing layer and the cushion layer, respectively, via adhesive. In this case, if the polishing layer is soft, the surface of the polishing layer where the flange portion is located will be harder than other polished surfaces, increasing the rigidity only around the window portion, which may cause uneven wear and damage to the workpiece. Similarly, Patent Document 5 discloses that water leakage can be suppressed by providing a compression region in the support layer around the window member. In this case, however, the rigidity increases only around the window portion, which may cause uneven wear and damage to the workpiece. Furthermore, in conventional polishing pads such as those described in Patent Documents 1 to 5, through holes are formed using a die or the like. For example, Patent Document 3 describes cutting out second and third through holes within a first through hole using a guide member. Patent Document 2 describes forming through holes using a die. In this way, conventional methods involve manually aligning the through holes and then cutting them out, which leads to problems such as human error and the time required for alignment, resulting in low processing efficiency and unstable quality. On the other hand, the method described in Patent Document 6 is a so-called integrated type, in which an adhesive layer or cushion layer with through holes provided at positions corresponding to the window member's position on the first sheet is bonded to a first sheet in which a window member is embedded (a window member is integrally formed in a part of the first sheet), so that the positions of the window member and the through holes are the same. As a result, the pad and the window member exist on the same plane as the ground, so that the window member may reflect light, and the acquisition of the window member's position information may fail. If the ambient brightness is reduced to prevent reflection, it may become difficult to identify the position of the window member. Furthermore, in the method described in Patent Document 6, errors may occur when reading position information including information about the contour of the endpoint detection window and its center position, or when reading the center position of the endpoint detection window and the center position of the formed hole. If the positions of the window member and the through hole are misaligned during bonding due to these errors, the product cannot be commercialized.

[0007] The present invention has been made in view of the above points, and its first objective is to provide a method for manufacturing a polishing pad with an endpoint detection window (with a window member) that improves the adhesion between the window member and the polishing pad and reduces uneven wear. Furthermore, a second objective of the present invention is to provide a method for manufacturing polishing pads that reduces the effort required for manual operation and allows for simple and efficient production. [Means for solving the problem]

[0008] As a result of diligent study on the above first problem, the present inventors have found that by pressing the polishing pad, which includes a first sheet having a first through-hole, a second sheet having a second through-hole, and a window member, the first sheet has a polishing surface for polishing an object to be polished, the second sheet is bonded to the surface of the first sheet opposite to the polishing surface, the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole, and the window member is positioned inside the first through-hole and on the second sheet such that when the polishing surface is the upper surface and the surface of the second sheet opposite to the surface bonded to the first sheet is the lower surface, the uppermost part of the window member is lower than the polishing surface, and by pressing the polishing pad with a press machine using a spacer of a predetermined thickness, the adhesion between the back surface of the window member and the adhesive surface of the second sheet is improved and uneven wear is less likely to occur, thus completing the present invention. Furthermore, after diligently investigating the second problem, the inventors discovered that by using a colored film to identify the position of the first through-hole, they could efficiently manufacture a polishing pad with an endpoint detection window, thus completing the present invention. In other words, the present invention provides the following:

[0009] [1] A polishing pad comprising a first sheet having a first through hole, a second sheet having a second through hole, and a window member, The first sheet has a polishing surface for polishing the object to be polished, The second sheet is bonded to the side of the first sheet opposite to the polished surface. The second through-hole is formed such that, when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. When the polished surface is considered the upper surface and the side of the second sheet opposite to the side bonded to the first sheet is considered the lower surface, the window member is positioned within the first through-hole and on the second sheet such that the uppermost part of the window member is lower than the polished surface. The process of preparing the polishing pad, and A process of pressing the polishing pad with a press machine, which has an upper press machine and a lower press machine, by placing the polishing pad on the lower press machine, placing a spacer of a predetermined thickness around the polishing pad on the lower press machine, and pressing the polishing pad with the press machine. A method for manufacturing an abrasive pad, including, The thickness S of the spacer is within the range of the thickness of the second sheet ≤ S ≤ (H-Tave1), and the press pressure is 0.8 MPa or less. The aforementioned manufacturing method. (Here, S is the thickness of the spacer, H is the thickness of the polishing pad before pressing, and Tave1 is the average depth from the polishing surface to the top surface of the window member before pressing.) [2] The manufacturing method according to [1], comprising pressing the polishing pad with a press machine so that |Tave1-Tave2| ≤ 40 μm. (Here, Tave1 is the average depth from the polished surface before pressing to the top surface of the window member, and Tave2 is the average depth from the polished surface after pressing to the top surface of the window member.) [3] The process of preparing the polishing pad is as follows: A step of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet, A step of forming a first through hole that penetrates the first sheet in the thickness direction from the polished surface to the opposite surface, A step of bonding a first sheet and a second sheet such that the opposite surface of the first sheet faces the surface of the second sheet having an adhesive; A step of disposing a film in the first through-hole of the first sheet to which the second sheet is bonded, where the film is a colored film and has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side; A step of acquiring position information of the first through-hole; A step of forming a second through-hole penetrating the second sheet in the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side based on the acquired position information, where the second through-hole is formed such that the outer peripheral portion of the second through-hole is covered by the outer peripheral portion of the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side; A step of removing the film after forming the second through-hole and disposing a window member on the surface of the first through-hole having the adhesive of the second sheet; The manufacturing method according to [1] or [2], including the above steps. 〔4〕 The film has a color different from the color of the polished surface of the first sheet, The manufacturing method according to [3], where the step of acquiring the position information includes specifying the position of the first through-hole by utilizing the color difference between the film and the polished surface. 〔5〕 When the polished surface of the first sheet is on the upper side, a photographing unit for photographing the first sheet from above the polished surface of the first sheet; A control unit for specifying the position of the first through-hole from the image photographed by the photographing unit and instructing to form a second through-hole penetrating the second sheet in the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side based on the information of the specified position of the first through-hole; A hole forming unit for forming the second through-hole according to the instruction of the control unit; The method further includes a step of preparing a cutting device including the above components, and The step of obtaining the position information includes the control unit identifying the position of the first through hole from the image captured by the imaging unit, and the manufacturing method according to [3] or [4]. 〔6〕 The step of obtaining the position information includes the control unit identifying the position of the film by identifying the color difference between the film and the polished surface in the image captured by the imaging unit, and the manufacturing method according to [5]. 〔7〕 The step of forming the second through hole includes the hole forming unit forming a second through hole that penetrates the second sheet into the first through hole when viewing the first sheet from the polished surface side in the thickness direction based on the obtained position information of the first through hole, and the manufacturing method according to [5] or [6]. 〔8〕 The step of forming the second through hole includes forming the second through hole such that the center of the first through hole and the center of the second through hole are substantially the same when viewing the first sheet from the polished surface side in the thickness direction based on the position information of the first through hole, and the manufacturing method according to any one of [3] to [7]. 〔9〕 The step of obtaining information on a position (equidistant position) that is at an equal distance from the centers of all the first through holes when viewing the first sheet from the polished surface side in the thickness direction based on the position information of the first through hole, and the step of circularly cutting the first sheet with the second sheet bonded thereto so as to include the first through hole with an arbitrary radius centered on the equidistant position based on the equidistant position information are further included, and the manufacturing method according to any one of [3] to [8]. 〔10〕 The manufacturing method according to any one of [3] to [9], wherein the shapes of the first through hole and the second through hole when viewed from the polished surface side of the polishing pad in the thickness direction are both circular. 〔11〕 The manufacturing method according to any one of [3] to

[10] , wherein the equivalent circle diameter of the first through hole is 5 to 30 mm larger than the equivalent circle diameter of the second through hole. 〔12〕 The manufacturing method according to any one of [3] to

[11] further includes the step of providing grooves (for example, embossed grooves) on the polished surface of the first sheet.

[13] The step of arranging the window member is: A manufacturing method according to any one of [3] to

[12] , comprising arranging the window member such that, when the polished surface is the upper surface and the side of the second sheet opposite to the side adhering to the first sheet is the lower surface, the uppermost part of the window member is higher than the lowermost part of the groove.

[14] A method for manufacturing an abrasive pad, comprising the following steps: A step of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet, A step of forming a first through hole that penetrates the first sheet in the thickness direction from the polished surface to the opposite surface, A step of bonding the first sheet and the second sheet together such that the opposite side of the first sheet and the side of the second sheet having adhesive face each other. A step of placing a film in the first through-hole of the first sheet to which the second sheet has been bonded, wherein the film is a colored film and has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side. A step of acquiring positional information of the first through hole, A step of forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction, based on the acquired position information, wherein the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. The steps of removing the film after the formation of the second through-hole and placing the window member inside the first through-hole and on the surface of the second sheet having adhesive, A manufacturing method that includes this.

[15] When the polishing surface of the first sheet is facing upwards, a camera unit that photographs the first sheet from above the polishing surface of the first sheet, A control unit identifies the position of the first through-hole from the image captured by the imaging unit, and based on the information of the identified position of the first through-hole, commands the first sheet to form a second through-hole that penetrates the second sheet within the first through-hole when viewed from the polishing surface side in the thickness direction, A hole forming unit that forms the second through hole in accordance with the command of the control unit, The process further includes a step of preparing a cutting machine equipped with, The manufacturing method according to

[14] , wherein the step of acquiring the position information includes the control unit identifying the position of the first through hole from the image captured by the imaging unit.

[16] The manufacturing method according to

[15] , wherein the step of acquiring the position information includes the control unit identifying the position of the film by identifying the difference in color between the film and the polished surface in the image captured by the imaging unit. [Effects of the Invention]

[0010] Regarding the first problem, the present invention makes it possible to improve the adhesion between the back surface of the window member of a polishing pad with an endpoint detection window (window member) and the adhesive surface of the second sheet. As a result, it is possible to manufacture a polishing pad in which the window member is less likely to peel off from the polishing pad. In addition, since the window member is fixed in close contact with the adhesive surface, the seepage of slurry can also be suppressed. Furthermore, uneven wear is less likely to occur during polishing. Regarding the second issue, according to the present invention, a polishing pad with an endpoint detection window can be manufactured simply and efficiently while reducing the effort required for manual operation by a person. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a substantially cross-sectional view (cut end view) in the thickness direction of a polishing pad obtained by the method of the present invention. [Figure 2] Figure 2 shows a view of a polishing pad obtained by the method of the present invention, as seen from the polishing surface in the thickness direction. [Figure 3A]Figure 3A is a schematic cross-sectional view (cut end view) of an object being polished using a polishing pad according to one embodiment of the method of the present invention. [Figure 3B] Figure 3B is a schematic cross-sectional view (cut end view) along line AA in Figure 2 when polishing an object to be polished using a polishing pad according to one embodiment of the method of the present invention. [Figure 4] Figure 4 shows an example of the placement of spacers used in the pressing process in the method of the present invention. [Figure 5] Figure 5 shows a polishing pad manufactured by the method of the present invention (before the pressing process). [Figure 6] Figure 6 shows a polishing pad (during pressing) manufactured by the method of the present invention. [Figure 7] Figure 7 is a diagram illustrating each step of the method of the present invention. [Figure 8] Figure 8 shows the total pad thickness of the pad in Example 1. [Figure 9] Figure 9 shows the pad thickness around the first of the three window members in Example 1. [Figure 10] Figure 10 shows the pad thickness around the second of the three window members in Example 1. [Figure 11] Figure 11 shows the pad thickness around the third of the three window members in Example 1. [Modes for carrying out the invention]

[0012] The following describes embodiments for carrying out the present invention.

[0013] <<Manufacturing method for polishing pads>> <First aspect> A method for manufacturing an abrasive pad according to a first aspect of the present invention is: A polishing pad comprising a first sheet having a first through hole, a second sheet having a second through hole, and a window member, The first sheet has a polishing surface for polishing the object to be polished, The second sheet is bonded to the side of the first sheet opposite to the polished surface. The second through-hole is formed such that, when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. When the polished surface is considered the upper surface and the side of the second sheet opposite to the side bonded to the first sheet is considered the lower surface, the window member is positioned within the first through-hole and on the second sheet such that the uppermost part of the window member is lower than the polished surface. The process of preparing the polishing pad, and A process of pressing the polishing pad with a press machine, which has an upper press machine and a lower press machine, by placing the polishing pad on the lower press machine, placing a spacer of a predetermined thickness around the polishing pad on the lower press machine, and pressing the polishing pad with the press machine. A method for manufacturing an abrasive pad, including, The thickness S of the spacer is within the range of the thickness of the second sheet ≤ S ≤ (H-Tave1), and the press pressure is 0.8 MPa or less. The manufacturing method is as described above. (Here, S is the thickness of the spacer, H is the thickness of the polishing pad before pressing, and Tave1 is the average depth from the polishing surface to the top surface of the window member before pressing.) The following describes each step.

[0014] <1. Steps to prepare the polishing pad> The step of preparing a polishing pad includes preparing a polishing pad comprising a first sheet having a first through-hole, a second sheet having a second through-hole, and a window member, wherein the first sheet has a polishing surface for polishing an object to be polished, the second sheet is bonded to the surface of the first sheet opposite to the polishing surface, the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole, and the window member is positioned inside the first through-hole and on the second sheet such that when the polishing surface is the upper surface and the surface of the second sheet opposite to the surface bonded to the first sheet is the lower surface, the uppermost part of the window member is lower than the polishing surface. As long as the polishing pad has the above configuration, there are no particular restrictions, and a commercially available polishing pad may be used, or a polishing pad that has been manufactured may be used. Furthermore, the polishing pad may be manufactured by the method described in the second embodiment. The polishing pad may be buffed and may have grooves. The following describes each configuration.

[0015] (First sheet) The first sheet is a sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface). The first sheet may consist of one layer or two or more layers. However, if the first sheet consists of two or more layers, all of the two or more layers must be penetrated by the first through-hole. If it consists of two or more layers, it is preferable that at least the layer having the polishing surface (polishing layer) is made of resin (resin sheet). Examples of resins include polyurethane resin, polyester resin, and polyethylene resin. Among these, polyurethane resin is more preferable considering compression characteristics and flexibility. The first sheet may consist of one type of resin or two or more types of resin. When the first sheet consists of multiple layers, the layer having the polishing surface is called the polishing layer, and the other layers below the polishing layer when viewed in the thickness direction with the polishing surface facing upwards are sometimes called the base layer. When the first sheet consists of multiple layers, even if the layer on the polishing surface side (polishing layer) is made of a soft resin, a certain degree of hardness can be ensured, making it easy to handle and thus easy to bond with the second sheet. When the first sheet consists of a polishing layer and a base layer, it is preferable that at least the polishing layer is made of resin. The base layer may be composed of a resin, a resin-containing nonwoven fabric, a resin-free nonwoven fabric, or a combination of two or more of these layers. In particular, the base layer is preferably composed of a resin or a resin-containing nonwoven fabric, and more preferably a flexible sheet or nonwoven fabric base made of polyethylene terephthalate resin (preferably a polyurethane resin-containing nonwoven fabric base made by impregnating a nonwoven fabric with polyurethane resin). The first sheet may be a commercially available one or a manufactured one. When manufacturing the first sheet, for example, a first sheet having an abrasive layer and a base layer can be manufactured by wet-forming a polyurethane resin film and laminating it with a flexible sheet base or nonwoven fabric base made of polyethylene terephthalate resin. The abrasive layer may be used alone as the first sheet without laminating the abrasive layer and the base layer, or the abrasive layer may be laminated with another sheet to form a first sheet consisting of two or more layers. Furthermore, when manufacturing the first sheet, for example, a first sheet having an abrasive layer and a base layer can be manufactured by wet-forming a polyurethane resin film and laminating it with a flexible sheet made of polyethylene terephthalate resin, referring to Japanese Patent No. 5421635 and Japanese Patent No. 5844189.

[0016] If the first sheet has a multilayer structure, the multiple layers can be bonded and fixed together using an adhesive, applying pressure as needed. There are no particular restrictions on the adhesive used, and any adhesive known in the art can be arbitrarily selected and used. Alternatively, the multiple layers can be directly bonded and fixed together by applying pressure and / or heating.

[0017] Furthermore, the first sheet is preferably one that has open cells. Here, open cells refer to foaming in which adjacent cells are connected to each other by interconnecting pores. Specifically, it may be a resin produced by a wet film deposition method, or a foam produced by dry molding or injection molding. Preferably, it is produced by a wet film deposition method, as it is soft and can be expected to have good bending motion (compression recovery characteristics). If the first sheet consists of two or more layers, it is preferable that at least the layer closest to the polishing surface (polishing layer) has open cells. All layers constituting the first sheet may also have open cells. From the viewpoint of handling, a configuration in which a resin layer having open cells (polishing layer) is laminated with a flexible sheet or nonwoven fabric substrate made of polyethylene terephthalate resin (preferably a polyurethane resin-containing nonwoven fabric substrate manufactured by impregnating a nonwoven fabric with polyurethane resin) is preferred. In this specification, the term "resin formed by the wet film-forming method" refers to a resin formed by the wet film-forming method (preferably a polyurethane resin). The wet film-forming method is a method in which the resin to be formed is dissolved in an organic solvent, the resin solution is applied to a sheet-like substrate, and then the substrate is passed through a coagulation solution (water) to solidify the resin. Resins formed by the wet film-forming method generally have a plurality of teardrop-shaped bubbles (which are anisotropic and have a structure in which the diameter increases from the polishing surface downwards on the polishing pad) formed by desolvating the organic solvent. Therefore, a resin formed by the wet film-forming method can also be described as a resin having a plurality of teardrop-shaped bubbles. It is preferable that the plurality of teardrop-shaped bubbles are in the form of open bubbles. Furthermore, it is preferable that the first sheet or the polishing layer constituting the first sheet is made of a wet film-forming sheet (preferably a polyurethane sheet), more preferably a polyurethane sheet containing a plurality of teardrop-shaped bubbles, and even more preferably a polyurethane sheet containing a plurality of teardrop-shaped bubbles and having open bubbles in which some or all of the bubbles are connected by connecting holes. If the first sheet or polishing layer has open bubbles with connecting holes, open bubbles also open on the sides of the first through-holes provided in the first sheet or polishing layer, and a portion of them communicate with the polishing surface or groove area. As a result, slurry and polishing debris that enter the first through-holes during polishing are moved to the sides of the first through-holes by the centrifugal force generated during polishing and discharged to the polishing surface or groove area through the open bubbles with connecting holes. This prevents a decrease in light transmittance over time due to the accumulation of polishing debris in the first through-holes, leading to a longer lifespan for the polishing pad. The first sheet may be transparent, semi-transparent, or opaque, but it is preferable that it be opaque.

[0018] The first sheet has a polishing surface for polishing the workpiece. The polishing surface refers to the surface that comes into contact with the workpiece when polishing it using a polishing pad. There are no particular limitations on the workpiece, and examples include product substrates (e.g., including multiple memory dies or processor dies), test substrates, bare substrates, and semiconductor substrates. The substrate can be from various stages of integrated circuit manufacturing; for example, the substrate can be a bare wafer or one or more deposited layers and / or pattern-forming layers. The first sheet may also be called a polishing layer. The side opposite the polishing surface (opposite side) is the side of the first sheet opposite the polishing surface, and is the side that comes into contact with the second sheet.

[0019] The thickness of the first sheet or polishing pad can be determined in accordance with the Japanese Industrial Standard (JIS K 6505) using a Shopper-type thickness measuring instrument (pressure surface: circular with a diameter of 1 cm). Specifically, it is as follows: Prepare a sample measuring 10 cm x 10 cm. Place the sample on the measuring instrument with the surface facing upwards. Apply a load of 100 g / cm². 2 Place the pressured surface onto the sample and measure the thickness after 5 seconds. Measure at 5 points per sample and use the average value as the thickness. If a 10cm square sample cannot be obtained, use the average of 5 points. There are no particular restrictions on the thickness of the first sheet, but it is preferably 0.5 to 3 mm, more preferably 0.6 to 2.8 mm, even more preferably 0.7 to 2.6 mm, even more preferably 0.8 to 2.5 mm, even more preferably 0.8 to 2.3 mm, and even more preferably 1.0 to 2.2 mm. There are no particular restrictions on the thickness of the polishing pad, but the thickness of the polishing pad before the pressing process is preferably 0.5 to 5 mm, more preferably 0.6 to 4 mm, even more preferably 0.7 to 3.5 mm, even more preferably 0.8 to 3.3 mm, even more preferably 1.0 to 3.0 mm, even more preferably 1.1 to 2.8 mm, even more preferably 1.2 to 2.6 mm, and even more preferably 1.2 to 2.4 mm.

[0020] (Compressibility and compressive modulus) In this specification, compressibility is an indicator of softness, and compressive modulus is an indicator of how easily a material returns to its original shape after compression deformation. The compressibility can be determined according to the Japanese Industrial Standard (JIS L 1021) using a Shopper-type thickness gauge (pressure surface: circular with a diameter of 1 cm). Specifically, it is as follows: The thickness t0 is measured after applying an initial load for 30 seconds from a no-load state. Next, the thickness t1 is measured after applying a final load for 5 minutes from the state of thickness t0. Then, all loads are removed from the state of thickness t1, and after leaving it for 5 minutes (to a no-load state), the thickness t0' is measured again after applying the initial load for 30 seconds. The compressibility can be calculated using the formula: Compressibility (%) = 100 × (t0 - t1) / t0 (Note that the initial load is 100 g / cm²). 2 The final load was 1120g / cm². 2 The compressive modulus can be calculated using the formula: Compressive modulus (%) = 100 × (t0'-t1) / (t0-t1) (Note that the initial load is 100 g / cm²). 2 The final load was 1120g / cm². 2 (That is.) The compression ratio of the first sheet is preferably 1-60%, more preferably 2-55%, and even more preferably 3-50%. The compression modulus of the first sheet is preferably 50-100%, more preferably 60-99%, and even more preferably 85-99%. When the compression modulus is within the upper range, the pad compresses during the pressing process, causing the press platen on the press machine to press against the window member, ensuring sufficient adhesion between the window member and the adhesive layer, and then allowing it to return to its original shape. Furthermore, because the compressibility and / or compressive modulus are within the above range, the polishing pad is more easily pushed in by the workpiece as it passes over the first through-hole, and its recovery properties are excellent. As a result, the bending and stretching motion when the first sheet is compressed and released makes it easier to suppress the adhesion of polishing debris that accumulates on the opening wall. Moreover, a slurry flow is created inside the first through-hole, and the polishing debris that has accumulated on the outer circumference of the first through-hole is easily carried by the slurry flow and discharged from the groove. This makes it easier to prevent slurry from remaining inside the opening.

[0021] (Buffing) If a skin layer exists on the polishing surface after the first sheet is manufactured, the skin layer may be buffed. Therefore, the polishing surface of the first sheet of the polishing pad may be buffed. When buffing (grinding), the polishing surface should be ground to a thickness of 50 to 300 μm, preferably 80 to 250 μm, using sandpaper or the like. Buffing (grinding) removes the skin layer and creates openings on the polishing surface that originate from bubbles formed during wet film formation. This improves the slurry retention. Also, if the first sheet or its polishing layer has continuous bubbles, buffing makes it easier for slurry and polishing debris to be discharged from the first through-holes through the connecting holes to the polishing surface.

[0022] (groove) The polishing pad may have grooves on the polishing surface of the first sheet. Since the grooves do not penetrate the first sheet in the thickness direction, they can be distinguished from the first through-holes. Examples of grooves include embossed grooves obtained by embossing the polishing surface, and cut grooves obtained by cutting with a cutting tool. Among these, embossed grooves are preferred. By providing grooves such as embossed grooves, burrs are less likely to form on the polishing surface, and a polishing pad suitable for finish polishing can be obtained. Embossed grooves can be obtained, for example, by embossing. Figure 2 shows a configuration in which embossed grooves 8 are provided on the polishing surface. Note that for simplicity, grooves such as embossing are not shown in Figures 4 and 7, but the configuration may include grooves. The groove may be provided such that, with the polished surface facing upward, the top of the window member is at the same level as the bottom of the groove, or it may be provided so that the top of the window member is higher than the bottom of the groove, or it may be provided so that it is lower than the bottom of the groove. However, it is preferable that the top of the window member is at the same level as or lower than the bottom of the groove, and it is more preferable that the top of the window member is higher than the bottom of the groove. Figure 1 shows an configuration in which the top 4' of the window member 4 is higher than the bottom 8' of the groove 8. With this configuration, slurry and polishing debris that flow into the surface of the window member in the first through-hole are discharged to the outside through the groove connected to the side of the first through-hole by the centrifugal force during polishing, so that slurry and polishing debris are less likely to remain on the surface of the window member (Figures 2 and 3B). The groove depth is not particularly limited as long as it is less than the thickness of the first sheet, but it is preferably 50-90% of the thickness of the first sheet, and more preferably 60-80%. Furthermore, if the first sheet is composed of two or more layers, the groove depth is preferably less than or equal to the thickness of the polishing layer, more preferably 50-90% of the thickness of the polishing layer, and even more preferably 60-80%. A deeper groove depth is preferable because if the groove disappears during the polishing process, the flowability of the polishing slurry is lost and the polishing performance deteriorates, thus ending the life of the polishing pad. On the other hand, in the case of embossed grooves, etc., increasing the groove depth requires increasing the processing pressure or processing temperature, which may cause deterioration of the surface of the first sheet. These problems are less likely to occur when the groove depth is within the above range. There are no particular restrictions on the number or shape of grooves; they can be adjusted as appropriate to suit the intended use of the polishing pad. Examples of groove shapes include grid, radial, concentric, and honeycomb patterns, and these can be combined.

[0023] (Second sheet) The second sheet refers to a sheet that can be bonded (adhered) to other materials (for example, the first sheet or window components). The second sheet has a surface (the second sheet surface) that is in contact with the side of the first sheet opposite to the polished surface (the opposite side). An adhesive is applied to the second sheet surface that is in contact with the opposite side of the first sheet. The first sheet and the second sheet are bonded together via this adhesive. That is, the first sheet and the second sheet are bonded together such that the opposite side of the first sheet and the second sheet surface are in contact with each other via the adhesive. The second sheet is not particularly limited as long as it has an adhesive on at least one surface. Examples of materials for the sheet constituting the second sheet include polyolefin sheets such as polyethylene (PE), polypropylene (PP), and ethylene-propylene copolymer; polyester sheets such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN); vinyl chloride sheets; vinyl acetate sheets; polyimide sheets; polyamide sheets; fluororesin sheets; resin-impregnated nonwoven fabrics; nonwoven fabrics; and woven fabrics. Furthermore, it is preferable that the second sheet is a non-porous sheet that does not allow slurry to penetrate inside. Among these, a polyester sheet is more preferable for the second sheet from the viewpoint of physical properties (e.g., dimensional stability, thickness accuracy, processability, tensile strength) and economics, and among these, a polyethylene terephthalate (hereinafter abbreviated as PET) sheet is particularly preferable. There are no particular restrictions on the adhesive used, as long as it can bond the first sheet and the second sheet together; various adhesives can be used. Examples of adhesives include acrylic, urethane, and epoxy adhesives. Among these, acrylic adhesives are preferred because they have good compatibility with window components. Furthermore, the adhesive surface of the second sheet may be covered with release paper or the like until it is bonded to the first sheet. The release paper can be peeled off the surface of the second sheet when bonding the second sheet to the first sheet. This maintains the adhesive strength of the adhesive and prevents impurities such as dust and dirt from getting between the second sheet and the first sheet. As a result, the problem of delamination that may occur between the second sheet and the first sheet during polishing can be reduced. The second sheet may be a commercially available product or a manufactured product. The second sheet may consist of one layer or two or more layers. If it consists of two or more layers, the materials constituting each layer may be the same or different. If the second sheet has a multi-layer structure, the layers may be bonded and fixed together using an adhesive or sealant, and pressurized as needed. There are no particular restrictions on the adhesive or sealant used in this case, and any adhesive or sealant known in the art may be arbitrarily selected and used. Alternatively, the layers may be directly bonded and fixed together by pressurizing and / or heating. If the second sheet consists of two or more layers, the two or more layers may be directly bonded together or bonded together via an adhesive or sealant. Furthermore, if the material constituting the second sheet is in the form of single-sided or double-sided tape, the adhesive surface of the single-sided or double-sided tape may be used to bond two or more layers constituting the second sheet together. If the second sheet is composed of two or more layers, all of the two or more layers are penetrated by the second through-hole. Furthermore, the second sheet may be composed of one type of material or of two or more types of materials. The second sheet may have adhesive not only on the surface in contact with the first sheet, but also on the opposite surface. In this case, it is preferable that the surface opposite to the surface in contact with the first sheet is covered with release paper or the like. This allows the release paper to be peeled off from the surface of the second sheet constituting the polishing pad that is opposite to the surface in contact with the first sheet during the polishing process of the workpiece, and the polishing pad to be fixed to the polishing platen using the adhesive. One method for bonding the second sheet and the first sheet is to overlap them so that the side of the second sheet with adhesive and the side of the first sheet opposite to the abrasive layer face each other (are in contact), thereby bonding the second sheet and the first sheet together via the adhesive. The second sheet has lower transparency than the window member, preferably being semi-transparent or opaque, and more preferably opaque.

[0024] There are no particular restrictions on the thickness of the second sheet, but 0.01 to 2.0 mm is preferred, 0.02 to 2.0 mm is more preferred, 0.1 to 2.0 mm is even more preferred, 0.1 to 1.5 mm is even more preferred, 0.1 to 1.0 mm is even more preferred, 0.1 to 0.8 mm is even more preferred, 0.2 to 0.6 mm is even more preferred, 0.2 to 0.4 mm is even more preferred, and 0.2 to 0.3 mm is even more preferred. The thickness of the second sheet as used herein refers to the thickness of the second sheet when it is laminated with the first sheet. Therefore, the thickness of the second sheet does not include the thickness of the release paper that may cover the surface of the second sheet that is in contact with the first sheet (before it is laminated with the first sheet), but if there is release paper covering the surface opposite to the surface in contact with the first sheet, its thickness is included.

[0025] (First through-hole) The first through-hole is a hole that penetrates from the polished surface of the first sheet to the opposite surface of the first sheet when viewed in the thickness direction from the polished surface side of the first sheet. Preferably, the first through-hole penetrates the first sheet parallel to the thickness direction or perpendicular to the polished surface. The first through-hole may be provided as one in the first sheet, or as a plurality (preferably two or more, more preferably three or more). Furthermore, the plurality of first through-holes may be spaced apart from each other and independent of each other. In the first sheet 2 shown in Figure 7, three first through-holes are provided. These three first through-holes are formed at equal intervals on the circumference of a circle centered at the same point as the center of the polishing pad (that is, the center of one through-hole and the center of another through-hole adjacent to that through-hole are formed on the circumference of the circle with an angle (central angle) of 120 degrees centered at that point). Examples of the shape of the first through-hole when viewed from the polishing surface side of the polishing pad in the thickness direction of the polishing pad, the cross-sectional shape of the first through-hole when cut perpendicular to the thickness direction of the polishing pad, and / or the shape of the first through-hole on the polishing surface include circular, elliptical, triangular, square, hexagonal, octagonal, etc. Alternatively, it may be a shape in which multiple identical or different of the above shapes partially overlap each other. Among these, a circular shape is particularly preferred.

[0026] (Equivalent diameter of a circle) In this specification and in the claims, the equivalent diameter of a circle is the diameter of a perfect circle that corresponds to the area of ​​the figure being measured. The equivalent circular diameter of the first through-hole is the equivalent circular diameter of the first through-hole when viewed from the polishing surface side of the polishing pad in the direction of the polishing pad thickness, and corresponds to the diameter when the shape of the first through-hole when viewed from the polishing surface side of the polishing pad in the direction of the polishing pad thickness is circular. In the method of the present invention, the equivalent circular diameter of the first through-hole in any first sheet cross-section obtained by cutting the first sheet of the polishing pad perpendicular to the thickness direction (or parallel to the polishing surface) is substantially the same as the equivalent circular diameter of the first through-hole in any other first sheet cross-section obtained by cutting the first sheet perpendicular to the thickness direction. Therefore, the equivalent circular diameter of the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction may be the equivalent circular diameter of the first through-hole in the cross-section obtained when the first sheet is cut in a direction perpendicular to the thickness direction. There are no particular restrictions on the equivalent circular diameter of the first through-hole, but 5 to 40 mm is preferred, 7 to 30 mm is more preferred, and 10 to 28 mm is even more preferred.

[0027] (Second through hole) The second through-hole is a hole that, when viewed from the polishing surface side of the polishing pad in the thickness direction of the polishing pad, penetrates from the surface of the second sheet that is in contact with the first sheet to the surface of the second sheet that is opposite to the surface in contact with the first sheet. Preferably, the second through-hole penetrates the second sheet parallel to the thickness direction or perpendicular to the polished surface.

[0028] Examples of the shape of the second through-hole when viewed from the polishing surface side of the polishing pad in the thickness direction of the polishing pad, the cross-sectional shape of the second through-hole when cut perpendicular to the thickness direction of the polishing pad, and / or the shape of the second through-hole on the second sheet surface include circular, elliptical, triangular, square, hexagonal, octagonal, and composite shapes thereof. Alternatively, it may be a shape in which multiple identical or different shapes partially overlap each other. Among these, a circular shape is particularly preferred because it does not form corners where polishing debris tends to accumulate, and the adhesive surfaces to which the window member formed between the first and second through-holes is attached are evenly spaced, preventing areas where the window member is likely to peel off. In the polishing pad of the present invention, the cross-sectional shape of the first through-hole and the cross-sectional shape of the second through-hole when cut perpendicular to the thickness direction may be the same or different, but it is preferable that they be the same. Among these, it is preferable that the cross-sectional shape of the first through-hole and the cross-sectional shape of the second through-hole when cut perpendicular to the thickness direction are both circular. That is, it is preferable that the shape of the first through-hole and the shape of the second through-hole are both circular when viewed in the thickness direction from the polishing surface side of the polishing pad.

[0029] The second through-hole is provided such that, when viewed in the thickness direction from the polishing surface side of the polishing pad, the outer circumference 5' of the first through-hole covers the outer circumference 6' of the second through-hole (see Figure 2). More preferably, both the first and second through-holes are cylindrical in shape, and the second through-hole is provided such that the cylindrical central axis of the first through-hole coincides with the cylindrical central axis of the second through-hole. The statement that the outer periphery of the first through-hole covers the outer periphery of the second through-hole means that, when viewed from the polishing surface side in the thickness direction, the second through-hole is located within the first through-hole. If a film, described later, is placed within the first through-hole, this means that, when viewed from the polishing surface side in the thickness direction without the film, the second through-hole is located within the first through-hole. In the polishing pad obtained by the method of the present invention, the second through-hole is located within the first through-hole when viewed in the thickness direction, so the first and second through-holes are connected in the thickness direction of the polishing pad. Because the first and second through-holes are connected in the thickness direction of the polishing pad, light can be transmitted from the second through-hole side to the first through-hole side through a window member provided within the first through-hole, allowing for optical detection of the surface condition of the workpiece during polishing. Furthermore, the first through-hole 5 is positioned such that when the polishing pad is viewed from the polishing surface side in the thickness direction, a portion of the second sheet 3 (hereinafter referred to as the exposed portion 7 of the second sheet) and the second through-hole 6 are exposed. This allows the window member to be positioned inside the first through-hole and on the second through-hole and the exposed portion of the second sheet 3. When the first through-hole of the polishing pad is viewed from the polishing surface side in the thickness direction, the second through-hole and a portion of the second sheet can be seen. This portion of the second sheet is called the exposed portion. Referring to Figure 1, in the cross-sectional view in the thickness direction of the polishing pad 1 of the present invention, the first through hole 5 is provided in the first sheet 2 located on the exposed portion 7 and the second through hole 6. The second through-hole may be one in the second sheet, or there may be two or more through-holes that are spaced apart from each other and independent of each other. It is preferable that the number of first through-holes and the number of second through-holes are equal. When there are multiple first through-holes and multiple second through-holes, it is preferable that each first through-hole is located on each second through-hole and its exposed portion in the second sheet. It is preferable that no window member is placed inside the second through-hole. Furthermore, it is preferable that the second through-hole is hollow (no member is placed inside).

[0030] (Equivalent diameter of a circle) In this specification and the claims, the equivalent circular diameter of the second through-hole is the equivalent circular diameter of the second through-hole when viewed from the polishing surface side of the polishing pad in the thickness direction of the polishing pad or when the second sheet is viewed in the thickness direction, and corresponds to the diameter when the shape of the second through-hole when viewed from the polishing surface side of the polishing pad in the thickness direction of the polishing pad is circular. In the polishing pad obtained by the method of the present invention, the equivalent circular diameter of the second through-hole in any second sheet cross-section obtained by cutting the second sheet of the polishing pad perpendicular to the thickness direction is equal to the equivalent circular diameter of the second through-hole in any other second sheet cross-section obtained by cutting the second sheet perpendicular to the thickness direction. Therefore, the equivalent circular diameter of the second through-hole may be the equivalent circular diameter of the second through-hole on the surface of the second sheet that is in contact with the first sheet. The equivalent circular diameter of the second through-hole is smaller than the equivalent circular diameter of the first through-hole. Conversely, the equivalent circular diameter of the first through-hole is larger than the equivalent circular diameter of the second through-hole. As long as the equivalent circular diameter of the first through-hole is larger than the equivalent circular diameter of the second through-hole, there are no particular restrictions on the size difference between the first and second through-holes. However, from the viewpoint of sufficiently suppressing blockage of the optical path by polishing debris and preventing peeling of the window member, it is preferable that the equivalent circular diameter of the first through-hole is 5 to 30 mm larger than the equivalent circular diameter of the second through-hole, more preferably 6 to 25 mm larger, and even more preferably 7 to 20 mm larger. Furthermore, when viewed in the thickness direction from the polishing surface side of the polishing pad, the outer circumference 5' of the first through hole is provided such that it covers the entire outer circumference 6' of the second through hole, and it is preferable that the equivalent circular diameter of the first through hole is 5 to 30 mm larger than the equivalent circular diameter of the second through hole, more preferably 6 to 25 mm larger, even more preferably 7 to 20 mm larger, even more preferably 8 to 20 mm larger, even more preferably 9 to 20 mm larger, and even more preferably 10 to 20 mm larger. Furthermore, when viewed in the thickness direction from the polishing surface side of the polishing pad, the outer circumference 5' of the first through hole is provided such that it covers the entire outer circumference 6' of the second through hole, and it is preferable that the equivalent circular diameter of the first through hole is 1.5 to 4 times the equivalent circular diameter of the second through hole, more preferably 2 to 4 times, and even more preferably 2.5 to 3 times. Furthermore, in the method of the present invention, when viewed from the polishing surface side of the polishing pad in the thickness direction of the polishing pad, it is preferable that the shortest distance between the outer periphery 6' of the second through hole and the outer periphery 5' of the first through hole (i.e., the shortest distance between any point on the outer periphery 6' of the second through hole and any point on the outer periphery 5' of the first through hole) is greater than 0, more preferably 2 to 15 mm, even more preferably 3 to 12 mm, and still more preferably 4 to 10 mm. If the size difference between the first and second through-holes is within the above range, the polishing slurry and polishing debris move to the outer periphery of the first through-hole due to centrifugal force during polishing, making it less likely for the polishing debris to block the optical path. Therefore, excellent light transmittance can be maintained, and a stable signal strength for endpoint detection can be obtained during polishing. In addition, because the exposed area of ​​the second sheet is sufficiently large, the adhesive strength between the window member and the second sheet can be maintained, preventing the window member from peeling off. As long as the equivalent diameter of the first through-hole is greater than the equivalent diameter of the second through-hole, there are no particular restrictions on the equivalent diameter of the second through-hole, however, the equivalent diameter of the second through-hole is preferably 1 to 20 mm, more preferably 2 to 18 mm, and even more preferably 5 to 15 mm.

[0031] (Window components) The window member has substantially the same shape as the first through-hole when viewed in the thickness direction from the polished surface. Preferably, it has the same shape as the first through-hole. By irradiating the workpiece with light through a window member, it is possible to detect the point at which the workpiece has reached the desired surface characteristics and planar state. The window member is positioned within the first through-hole and on the second sheet such that, when the polished surface is considered the upper surface and the side of the second sheet opposite to the side bonded to the first sheet is considered the lower surface, the uppermost part of the window member is lower than the polished surface. The window member is positioned within the first through-hole. Preferably, it is positioned within the first through-hole and on the second through-hole and exposed portion of the second sheet. Preferably, the window member is not positioned within the second through-hole. Referring to Figure 1, the window member 4, when viewed in a cross-sectional view in the thickness direction, is located within the first through-hole 5 and is provided on the second through-hole 6 of the second sheet 3 and the exposed portion 7. The window member adheres to the exposed portion of the second sheet. That is, the window member is bonded to the exposed portion of the second sheet via an adhesive present on at least one surface of the second sheet. Therefore, the window member is positioned on the exposed portion and within the first through-hole by the adhesive on the exposed portion of the second sheet. The window member may also be further adhered to the side surface of the first through-hole of the first sheet, but it is preferable that it is not. The window member is fixed on the exposed portion and within the first through-hole by the adhesive on the exposed portion. If the window member is adhered to the side surface of the first through-hole of the first sheet, it will not be able to move flexibly towards the exposed portion 7 and adhere tightly when pressed during the pressing process. Also, after the pressing is completed, a force acts on the first sheet to return it to its pre-press state, making it easier for the window member to separate from the exposed portion 7. On the other hand, because the window member is not bonded to the side surface of the first through-hole of the first sheet, the bonding between the window member 4 and the exposed portion 7 can be made stronger by pressing during the pressing process.

[0032] The window members are preferably made of resin. The resin constituting the window members is not particularly limited as long as it has transparency sufficient to transmit light, but it is preferable to use a material that has a light transmittance of 20% or more in the entire wavelength range of 300 to 700 nm, and more preferably a material that has a light transmittance of 50% or more. Examples of such materials include thermosetting resins such as polyurethane resin, polyester resin, phenolic resin, urea resin, melamine resin, epoxy resin, and acrylic resin; thermoplastic resins such as polyurethane resin, polyester resin, polyamide resin, cellulose resin, acrylic resin, polycarbonate resin, halogenated resins (polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, etc.), polystyrene resin, and olefin resins (polyethylene, polypropylene, etc.); rubbers such as butadiene rubber and isoprene rubber; photocurable resins that harden with light such as ultraviolet rays or electron beams; and photosensitive resins. Among these, polyurethane resin, polyester resin, acrylic resin, and polystyrene resin are preferred because they have appropriate stiffness at a thickness of 0.1 to 0.5 mm, offer excellent thickness accuracy, and have good compatibility with adhesives. Furthermore, it is preferable that the top surface of the window member be roughened or hydrophilized to prevent the slurry from being repelled. Window components may be commercially available or manufactured. Commercially available window components include: Mitsubishi Chemical Corporation's "Diafoil T910E" and "Diafoil T600E" made of polyester resin; Toyobo Co., Ltd.'s "Cosmoshine A4300", "Cosmoshine A2330", "Cosmoshine TA017", "Cosmoshine TA015", "Cosmoshine TA042", "Cosmoshine TA044", "Cosmoshine TA048", and "Softshine TA009" made of polymethyl methacrylate resin; and Mitsubishi Chemical Corporation's "Acryprene HBS006", "Acryprene HBXN47", and Commercially available products include "Kryprene HBS010", "Panlight Film PC-2151" manufactured by Teijin Chemicals Limited, "Sanduren SD009" and "Sanduren SD010" manufactured by Kaneka Corporation, "C000" manufactured by Sumitomo Chemical Co., Ltd., which is made of polycarbonate resin, "Yupilon H-3000" manufactured by Teijin Chemicals Limited, "C001" manufactured by Sumitomo Chemical Co., Ltd., which is made of acrylic resin / polycarbonate resin, "Zeonor ZF14" and "Zeonor ZF16" manufactured by Nippon Zeon Co., Ltd., which is made of alicyclic polyolefin resin, and "Arton Film" manufactured by JSR Corporation.

[0033] (Equivalent diameter of a circle) The window member has substantially the same shape as the first through-hole when viewed in the thickness direction from the polished surface, and preferably has the same shape as the first through-hole. The equivalent circle diameter of the window member is preferably less than or equal to the equivalent circle diameter of the first through-hole, more preferably in the range of "0.8 times the equivalent circle diameter of the first through-hole" to "the equivalent circle diameter of the first through-hole", even more preferably in the range of "0.9 times the equivalent circle diameter of the first through-hole" to "the equivalent circle diameter of the first through-hole", and still more preferably in the range of "0.95 times the equivalent circle diameter of the first through-hole" to "the equivalent circle diameter of the first through-hole", and may also be equal to the equivalent circle diameter of the first through-hole. Furthermore, it is preferable that the equivalent circular diameter of the window member is larger than the equivalent circular diameter of the second through-hole. It is preferable that the window member does not have connecting holes. Furthermore, it is preferable that the window member does not have open bubbles. Also, it is preferable that the window member does not have openings. This improves light transmission.

[0034] (Upper position of window component) In the method of the present invention, when the polished surface is the upper surface and the side of the second sheet opposite to the side that is bonded (adhered) to the first sheet is the lower surface, it is preferable to position the window member 4 such that the uppermost part 4' of the window member 4 is higher than the lowermost part 8' of the groove 8 (Figures 1 and 3A). In other words, it is more preferable that the position of the window member closest to the polished surface is higher than the deepest position (the position furthest from the polished surface) of the groove provided in the first sheet. This makes it easier for polishing debris that has moved to the outer circumference of the first through hole to flow into the groove together with the slurry. Furthermore, the first through-hole may or may not be connected to the groove, but it is preferable that it be connected (Figures 2 and 3B). Figure 3B shows the end face when the polishing pad of Figure 2 is cut between A and B. Polishing debris 10 generated during the polishing process of the workpiece is collected on the outer circumference of the first through-hole by centrifugal force 11, and then can flow out into the groove 8 connected to the first through-hole. As a result, polishing debris is more easily discharged from inside the first through-hole, preventing the formation of polishing debris aggregates that occur when polishing debris aggregates, and making it easier to suppress the occurrence of scratches caused by polishing debris aggregates.

[0035] The process of preparing the polishing pad preferably involves the following steps: A step of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet, A step of forming a first through hole that penetrates the first sheet in the thickness direction from the polished surface to the opposite surface, A step of bonding the first sheet and the second sheet together such that the opposite side of the first sheet and the side of the second sheet having adhesive face each other. A step of placing a film in the first through-hole of the first sheet to which the second sheet has been bonded, wherein the film is a colored film and has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side. A step of acquiring positional information of the first through hole, A step of forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction, based on the acquired position information, wherein the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. The steps of removing the film after the formation of the second through-hole and placing the window member inside the first through-hole and on the surface of the second sheet having adhesive, It is preferable to include the following. Each step will be described below.

[0036] <1-1. Process of preparing the first and second sheets> The method of the present invention comprises the steps of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet. The first sheet and the second sheet can be described below as those mentioned above. (Buffing) The first sheet may have a step of buffing the skin layer if a skin layer exists on its polished surface. When buffing (grinding), the polished surface should be ground to a thickness of 50 to 300 μm, preferably 80 to 250 μm, using sandpaper or the like. By buffing (grinding), the skin layer is removed and openings originating from air bubbles formed during wet film formation can be created on the polished surface. This improves the slurry retention. The buffing may be performed after the manufacture of the first sheet, before or after the formation of the first through-holes, and before or after the bonding of the first sheet and the second sheet, but it is preferable to perform it before the film placement step, more preferably before the bonding of the first sheet and the second sheet, and even more preferably before the formation of the first through-holes. Furthermore, the first sheet may be sliced ​​according to the desired thickness. (Groove formation) The method of the present invention may include a step of providing grooves on the polished surface of the first sheet. If the first sheet has a multilayer structure, grooves may be provided on the surface of the layer having the polished surface after multilayering. Furthermore, the step of providing grooves may be performed before or after forming the first through-hole, and before or after bonding the first sheet and the second sheet, but it is preferable to perform it before the film arrangement step, more preferably before the bonding step of the first sheet and the second sheet, and even more preferably before the process of forming the first through-hole. It is also preferable to perform it after buffing.

[0037] <1-2. Process for forming the first through hole> The method of the present invention includes the step of forming a first through-hole 5 that penetrates the polished surface of the first sheet 2 in the thickness direction (Figure 7(a)). Although grooves are omitted in Figure 7, grooves may be formed on the polished surface. The grooves can be provided as described above. Examples of the first through-hole include those mentioned above.

[0038] There are no particular limitations on the means for forming the first through hole; for example, a cutting machine or a hole-forming unit (hole-forming device) described later can be used. Other examples include a punching machine, a water jet device, a laser processing machine, and an ultrasonic cutter. Furthermore, the device described in Japanese Patent Application Publication No. 2022-149504 can also be used. In addition, a hole may be made in the thickness direction of the first sheet using a circular, elliptical, or other type of die (preferably a circular die). Among these, a cutting machine is particularly preferred.

[0039] Furthermore, the step of forming the first through-hole preferably includes forming the first through-hole at a position on the first sheet corresponding to each of the positions of the one or more points or small circles in the graphic data, based on graphic data in which one or more points or small circles are arranged at equal intervals on the circumference of a circle. Here, a small circle means a circle with a smaller radius or diameter than the above-mentioned circle. More specifically, when using a cutting machine described later, the above-mentioned graphic data is input to a control unit (e.g., a computer). Based on the graphic data information input to the control unit, the hole-forming unit of the cutting machine determines the position on the first sheet corresponding to the position of the points or small circles in the graphic data. For example, if the first sheet is a rectangular or square sheet when viewed in the thickness direction, the control unit may input information about the shape (size) of the sheet and the positions of the multiple points or small circles to be placed on the sheet, and based on the input information, the control unit may determine the position on the first sheet corresponding to the positions of the multiple points or small circles. Based on the determined position, the hole-forming unit drills a hole in the sheet placed at a predetermined position in the cutting machine, forming a first through-hole. In the case of a small circle, the first through-hole should be formed such that the position on the first sheet corresponding to the circumference of the small circle becomes the outer circumference of the first through-hole. In the case of a point, the first through-hole should be formed with a predetermined radius or diameter centered on the position on the first sheet corresponding to the point.

[0040] <1-3. Process of attaching the second sheet> The method of the present invention includes a step of bonding the first sheet and the second sheet together such that the side of the first sheet 2 opposite to the polished surface (opposite side) and the side of the second sheet 3 having adhesive face each other (Figure 7(b)). The first sheet and the second sheet can be bonded together by utilizing the adhesive strength of the adhesive on the second sheet. By bonding the first sheet and the second sheet together, the adhesive surface of the second sheet is exposed within the first through-hole when viewed from the polished surface in the thickness direction. This exposed adhesive surface is sometimes called the exposed surface.

[0041] <1-4. Step of placing the film in the first through-hole> The method of the present invention includes the step of placing a film 12 in a first through-hole 5 of a first sheet 2 to which a second sheet has been bonded (Figure 7(c)). Here, the film has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side. Preferably, the film is placed inside the first through-hole and on the adhesive surface (exposed surface) of the second sheet.

[0042] (film) When the first sheet is viewed from the polished surface side in the thickness direction, the film has substantially the same shape as the first through-hole, and preferably the same shape. Furthermore, the film is preferably the equivalent diameter of the first through-hole or less, preferably within the range of "0.8 times the equivalent diameter of the first through-hole" to "the equivalent diameter of the first through-hole", more preferably within the range of "0.9 times the equivalent diameter of the first through-hole" to "the equivalent diameter of the first through-hole", even more preferably within the range of "0.95 times the equivalent diameter of the first through-hole" to "the equivalent diameter of the first through-hole", and may also be equal to the equivalent diameter of the first through-hole.

[0043] There are no particular restrictions on the film material; for example, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, polyethylene coated paper, polypropylene coated paper, etc., can be used. Preferably, the film surface that comes into contact with the exposed surface of the second sheet is processed (non-adhesive) so that it does not easily adhere to the second sheet and can be easily released from the second sheet. Examples of non-adhesive processing include surface coating with silicone or fluororesin, and surface roughening. Commercially available films can be used. Examples of commercially available films include release paper, mold film, release liner, and separator. There are no particular restrictions on the thickness of the film, but it is preferable that when placed in the first through-hole, the uppermost surface of the film is at the same level as or lower than the polished surface of the first sheet, and more preferably lower than the polished surface. Examples of film thicknesses include films with a thickness of 70 to 100 μm.

[0044] There are no particular restrictions on the means by which the film is placed in the first through-hole; for example, the film can be placed in the first through-hole manually using appropriate tools such as tweezers, or by automated or robotic means.

[0045] (color) The film is a colored film. The term "colored film" does not include films that are not colored, i.e., colorless and transparent films. A colored film may be an opaque film, or a colored translucent film (e.g., white translucent, yellow translucent, black translucent, etc.). It is preferable that the film is opaque. It is preferable that the entire surface of the film facing the polished surface is colored. The film may also have color on the surface opposite to the polished surface, or the entire surface opposite to the polished surface may be colored. The film is preferably a film having a different color from the polished surface of the first sheet, and more preferably at least the entire surface of the film facing the polished surface has a different color from the polished surface of the first sheet. The film may have a different color on both the surface facing the polished surface and the other opposite surface. The color of the polished side of the film should be different from the color of the polished surface of the first sheet to the extent that the film region and the first sheet can be distinguished. Preferably, the color of the polished side of the film should be different in lightness (shade) from the color of the polished surface of the first sheet to the extent that the film region and the first sheet can be distinguished. Alternatively, the two may differ in saturation or hue. Among these, it is preferable that they differ in lightness (shade). Examples of cases where the brightness differs include, for instance, if the polished surface of the first sheet is black, the entire surface of the film facing the polished surface may be a bright color such as white, yellow, light blue, or pastel colors. Conversely, if the polished surface is white, the entire surface of the film facing the polished surface may be a dark color such as black, navy blue, gray, or dark colors. Examples of cases where the hues differ include, for instance, if the polished surface of the first sheet is orange, the entire surface of the film facing the polished surface may be blue, green, purple, etc. Also, if the polished surface is light blue, the entire surface of the film facing the polished surface may be red, yellow, green, etc. Examples of cases where the saturation differs include, for instance, if the polished surface of the first sheet is a pure color, the entire surface of the film facing the polished surface may be a color close to white, black, or gray. Conversely, if the polished surface is a color close to white, black, or gray, the entire surface of the film facing the polished surface may be a vivid color such as a bright red, blue, or yellow.

[0046] Among these, it is preferable that the color of at least the entire surface of the film facing the polished surface differs in brightness (shade) from the color of the polished surface of the first sheet. The difference in brightness (shade) is not particularly limited as long as it is a difference in brightness (shade) that can be distinguished by a camera. For example, when expressing brightness numerically using the Munsell color system, the difference in brightness between the color of the polished surface of the film and the color of the polished surface of the first sheet may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, or 8 or more. Among these, the larger the difference in brightness, the more preferable. Because the entire surface of the film on the polishing side has a different color from the polishing surface of the first sheet, the control unit can acquire image data of the first sheet captured by the camera in the cutting machine and determine the position of the film. Since the position of the film coincides with the position of the first through-hole, the position information of the first through-hole can be obtained by determining the position of the film. This makes it easy to determine the position of the second through-hole to be formed thereafter, and thus the second through-hole can be easily formed. Furthermore, this position information can be used to easily determine the center of the circle when cutting the first sheet, to which the second sheet has been bonded, into a circular shape. Furthermore, by placing the film inside the first through-hole of the first sheet, it is possible to prevent dust and dirt from adhering to the adhesive surface of the second sheet that is exposed inside the first through-hole. This improves the adhesion between the window member and the adhesive surface of the first sheet when the window member is placed inside the first through-hole in a subsequent process, and reduces the risk of the window member peeling off during polishing.

[0047] <1-5. Process for acquiring positional information of the first through-hole> The method of the present invention includes a step of acquiring positional information of a first through-hole. The step of acquiring positional information of a first through-hole includes identifying the position of the first through-hole. The position of the first through-hole may be identified by detecting the color of the film, by detecting the boundary line between the first sheet and the film, or by utilizing the color difference between the film and the polished surface. Among these, it is preferable to identify the position of the first through-hole by utilizing the color difference between the film and the polished surface. Examples of means for obtaining positional information of the first through-hole include means for detecting the color of the film to obtain positional information of the first through-hole, means for detecting the contour of the first through-hole to obtain positional information of the first through-hole, means for utilizing the color difference between the film and the polished surface to obtain positional information of the first through-hole, and combinations of these means. Among these, the means for utilizing the color difference between the film and the polished surface to obtain positional information of the first through-hole is preferred. As a means of detecting the color of the film and obtaining the position information of the first through-hole, for example, if the film is blue, the position information of the first through-hole can be determined by detecting the blue color on the first sheet. As a means of detecting the contour of the first through-hole and obtaining its positional information, for example, it can be obtained by detecting areas where the brightness value changes significantly from image data in which the film is placed inside the first through-hole. The contour shape can be calculated by detecting boundaries where the contrast between light and dark changes from the image data, converting it to a projected waveform, performing differential processing, and determining the peak points of the differential waveform as contour points. These can then be extracted using image processing methods such as the gradient method, Sobel method, Laplacian method, or Canny method. Even if the color and brightness of the film placed in the first through-hole are the same as those of the first sheet, if the film's position in the thickness direction is lower or higher than the polished surface, the boundary can be detected by the unevenness. Furthermore, even if the film in the first through-hole is on the same plane as the polished surface, the boundary can be detected by detecting the difference in brightness due to the gap between the first through-hole and the film. Moreover, the boundary of the first through-hole can also be detected by increasing the difference in brightness between the film and the polished surface. Means for obtaining positional information of the first through-hole by utilizing the difference in color between the film and the polished surface include, for example, a method of converting the RGB values ​​of each pixel in the captured image to brightness or luminance and binarizing them, a method of binarizing each of the three primary color components of the RGB values, or a method of defining an RGB color space and binarizing based on the distance of each pixel in the color space, which are means for binarizing and distinguishing between the film and the polished surface; a method of converting the RGB values ​​of each pixel to brightness or luminance and then determining the amount of color change between adjacent pixels, or a method of determining the amount of color change between adjacent pixels for each of the three primary color components of RGB, which are means for detecting the outline of the film image and distinguishing between the film and the polished surface based on the amount of color change between adjacent pixels. The step of acquiring the position information preferably includes the image capture unit of a cutting apparatus comprising an image capture unit, a control unit, and a hole forming unit capturing a first sheet on which the film is placed, and the control unit identifying the position of the film based on the image (image data) of the first sheet captured by the image capture unit, and more preferably the control unit identifying the position of the film by identifying the difference in color between the film and the polished surface in the image of the first sheet captured by the image capture unit. Since the position of the film coincides with the position of the first through hole, the position of the first through hole can be identified by identifying the position of the film. This makes it possible to acquire the position information of the first through hole. Alternatively, the position information of the first through hole can also be acquired by the control unit detecting the boundary between the first through hole and the first sheet based on the image (image data) of the first sheet captured by the image capture unit.

[0048] (Cutting equipment) The present invention preferably further includes the step of preparing a cutting apparatus comprising: an imaging unit that photographs the first sheet from above the polished surface of the first sheet when the polished surface of the first sheet is facing upward; a control unit that identifies the position of a first through hole from the image captured by the imaging unit and, based on the information of the position of the identified first through hole, instructs a hole forming unit to form a second through hole that penetrates the second sheet within the first through hole when the first sheet is viewed from the polished surface side in the thickness direction; and a hole forming unit that forms the second through hole according to the instruction of the control unit. Furthermore, the step of acquiring position information preferably includes the control unit identifying the position of the first through-hole from the image captured by the imaging unit. Examples of means for acquiring position information of the first through-hole (or methods for identifying the position of the first through-hole) include those described above. In particular, the step of acquiring position information preferably includes the control unit identifying the position of the film by identifying the difference in color between the film and the polished surface in the image captured by the imaging unit. The cutting apparatus preferably includes a stage in addition to the imaging unit, control unit, and hole forming unit. It is even more preferable to further include X-axis driving means and Y-axis driving means.

[0049] (Photography Department) The imaging unit photographs the first sheet from above the polished surface of the first sheet, with the polished surface of the first sheet facing upwards. Preferably, the imaging unit consists of a camera that photographs the first sheet on the stage from above and is fixed in a position where the entire shape of the first sheet can be photographed. For example, the imaging unit may be positioned above the stage on which the first sheet is mounted. The imaging unit is linked to the control unit, and the image data captured by the imaging unit is sent to the control unit.

[0050] (Control Unit) Image data captured by the imaging unit is sent to the control unit. The imaging unit and the control unit may be connected by wire or wireless means so that they can send and receive signals to each other, or so that the control unit can receive signals emitted by the imaging unit. The control unit preferably includes a display device such as a CRT or LCD and an input device such as a keyboard or mouse. The control unit can command the imaging unit to photograph the first sheet (or polishing pad), and the imaging unit can execute the command. The control unit identifies the position of the first through-hole from the image of the first sheet captured by the imaging unit. Based on the identified position information of the first through-hole, the control unit instructs the hole-forming unit to form a second through-hole that penetrates the second sheet within the first through-hole, when viewing the first sheet from the polishing surface side in the thickness direction. The control unit may have a dedicated processing device, or it may be a personal computer running CAD software. Alternatively, it may be a general-purpose computer running as a CAD system. By processing the image data in the control unit, the position of the film within the surface of the first sheet is identified. The method for processing the image data is the method described above for obtaining the position information of the first through-hole. Based on the information regarding the location of the identified first through-hole, the control unit instructs the hole-forming unit to form a second through-hole that penetrates the second sheet within the first through-hole, when viewed from the polishing surface side of the first sheet in the thickness direction. This instruction, or a signal containing the instruction, is sent to the hole-forming unit. The control unit and the hole-forming unit may be connected by wire or wireless so that they can send and receive signals to each other, or so that the hole-forming unit can receive signals sent by the control unit.

[0051] (hole forming part) The hole-forming unit (or hole-forming apparatus) forms a second through-hole that penetrates the second sheet in the thickness direction, according to a command from the control unit. The hole-forming unit has means (through-hole forming means) for forming a through-hole in the film and / or the second sheet. Examples of the through-hole forming means include a cutter and a drill. A drill is preferred among these. The cutter or drill makes it possible to form a through-hole in the film and / or the second sheet. The size of the drill is preferably the same as the diameter of the second through-hole. The hole-forming unit can also form a first through-hole as well as a second through-hole using the through-hole forming means. Furthermore, if the through-hole forming means is a cutter, the cutter may cut the first sheet, which is bonded to the second sheet, in the thickness direction according to the desired size of the polishing pad (so that it becomes the size of the desired polishing pad). Alternatively, the hole forming section may have a cutting means in addition to the through-hole forming means, and the cutting means may cut the first sheet, which is bonded to the second sheet, in the thickness direction according to the desired size of the polishing pad (so that it becomes the size of the desired polishing pad). When the through-hole forming means also forms the first through-holes, information regarding the desired size, number, and / or arrangement of the first through-holes (for example, arranging 3, 4, 5, or 6 through-holes at equal intervals on the circumference of a circle centered at a certain point (i.e., the centers of multiple through-holes are at equal intervals on the circumference)) is input to the control unit, and then this information is sent to the hole forming unit. Based on this information, the through-hole forming means forms the first through-holes. When cutting the first sheet bonded to the second sheet according to the desired size of the polishing pad, the control unit calculates the position of the center of the polishing pad from the position information of the first through-holes, and information regarding the calculated center position and the desired size of the polishing pad (e.g., radius) is sent to the hole forming unit. The through-hole forming means cuts the first sheet bonded to the second sheet to a predetermined size (for example, at a predetermined radius from the center position) based on the calculated center position (forming the outer circumference of the polishing pad). A cutter blade is preferred as the cutting means. The blade formed at the lower end of the cutter blade enables the cutting of the first sheet.

[0052] (stage) The cutting apparatus preferably has a stage. The stage includes a flat support plate for positioning a first sheet (or polishing pad). Preferably, the stage is configured to include a depressurization chamber provided on the lower side of the support plate and a vacuum blower that exhausts the air from the depressurization chamber to create negative pressure. In this case, the support plate has numerous fine suction holes that penetrate vertically from the upper surface of the support plate (the surface on which the first sheet is mounted) to the depressurization chamber below the support plate, and the first sheet is vacuum-adsorbed to the support plate and held in place by the vacuum blower setting the depressurization chamber to negative pressure.

[0053] (X-axis driving means / Y-axis driving means) The X-axis driving means and the Y-axis driving means are means for moving the hole-forming portion in the X-axis direction (front-to-back direction) and the Y-axis direction (left-to-right direction), respectively. The X-axis drive means and Y-axis drive means preferably include a pair of left and right guide rails and a guide bar. The pair of left and right guide rails (two guide rails) are fixed and extend parallel to each other in the front-rear direction, flanking the stage. The guide bar is preferably a single rectangular tubular bar positioned on the pair of guide rails, and is arranged to move freely along the pair of guide rails in the direction in which the guide rails extend (X-axis direction). The hole-forming portion is attached to the guide bar and is movable along the guide bar in the left-right direction (Y-axis direction). In other words, the guide bar moves in the X-axis direction by the guide rail, and the hole-forming portion on the guide bar moves in the Y-axis direction, allowing a through hole to be formed and / or the outer circumference of the pad to be cut at the desired position. The hole-forming section is preferably supported by a guide rail so as to be movable in the left-right direction and is configured to have a cutter holder. Preferably, a cutter blade and / or a drill are attached to the cutter holder, and a first through hole and a second through hole can be formed by the drill. In addition, the first sheet can be cut by a blade formed at the lower end of the cutter blade. Furthermore, the first through hole and the second through hole can also be formed by the cutter blade.

[0054] <1-6. Process for forming the second through-hole> The method of the present invention includes the step of forming a second through-hole 6 that penetrates the second sheet 3 within a first through-hole 5 when the first sheet 2 is viewed from the polishing surface side in the thickness direction, based on acquired positional information (Figure 7(d)). Here, the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. Examples of the second through-hole include those described above. Preferably, the step of forming the second through-hole includes, based on the acquired positional information, the hole-forming unit forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polished surface side in the thickness direction.

[0055] Furthermore, the step of forming the second through-hole preferably includes forming the second through-hole such that, based on the positional information of the first through-hole, the center of the first through-hole and the center of the second through-hole are substantially the same when viewed from the polished surface side in the thickness direction of the first sheet, and more preferably includes forming the second through-hole so that they are identical.

[0056] The formation of the second through-hole is preferably performed automatically by a cutting machine. Furthermore, as a means of forming the second through-hole such that the center of the first through-hole and the center of the second through-hole are substantially the same, for example, the center position of the first through-hole can be determined by calculating a center position that is equidistant from the outer circumference of the first through-hole or from multiple points on the outer circumference, based on the positional information of the first through-hole, and the second through-hole can be formed so that its center coincides with the center of the first through-hole and penetrates the second sheet. In this case, since the second through-hole is formed in the thickness direction from the polished surface side, the film inside the first through-hole will also be penetrated by the formation of the second through-hole.

[0057] <1-7. Cutting Process> The method of the present invention may further include the steps of: obtaining information on positions (equally distanced positions) that are at equal distances from the centers of all first through-holes when the first sheet is viewed from the polishing surface side in the thickness direction, based on the positional information of the first through-holes; and cutting the first sheet, which has been bonded with the second sheet, into a circular shape with the equidistant positions as the center and an arbitrary radius encompassing the first through-holes. This forms the outer edge of the polishing pad. The cutting step may be performed before forming the second through-holes, at the same time as forming the second through-holes, after forming the second through-holes, or after forming the second through-holes and before placing the window member. In this process, if the position information of the first through-hole includes information on the center positions of each of the multiple first through-holes when the first sheet is viewed from the polishing surface side in the thickness direction, the center position of each first through-hole can be determined based on this position information. Alternatively, if the position information of the first through-hole is information on the region of the first through-hole or the outer periphery of the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction, the center of the first through-hole can be calculated from the information on the region or outer periphery. Positions that are equidistant from the centers of all the first through-holes (equidistance positions) can be determined, and the first sheet, to which the second sheet has been bonded, can be cut in a circular shape with these equidistant positions as the center. Furthermore, it is preferable that the cutting process cuts the first sheet, to which the second sheet has been bonded, in a circular shape such that the first through-holes are included within the circle to be cut. If there is only one first through-hole, for example, a dummy pad can be prepared on a flat surface such as paper or a resin board, which has a through-hole of the same shape and size as the first through-hole and multiple pseudo-first through-holes on the same circumference (for example, a dummy pad in which three pseudo-first through-holes of the same shape and size as the first through-hole are arranged on the same circumference at an angle of 120 degrees to each other). By aligning one through-hole on the dummy pad with the position of the first through-hole on the first sheet, and recognizing the one first through-hole and two pseudo-first through-holes as three first through-holes, a position (equally distanced position) from the center of all first through-holes can be determined. The first sheet, which is formed by attaching the second sheet and the second through-holes together, can then be cut in a circular shape with the second through-holes formed around this equidistant position. At this time, by making the brightness and luminance of the surface of the dummy pad different from the brightness and luminance of the through-holes and pseudo-through-holes, the control unit can detect the through-holes, pseudo-through-holes and their contours.

[0058] <1-8. Process for arranging window components> The method of the present invention includes the step of removing the film 12 after the formation of the second through hole and placing the window member 4 inside the first through hole 5 and on the adhesive surface of the second sheet 3 (Figure 7(e)). Through this step, a polishing pad can be obtained. Examples of window members include those described above.

[0059] (Film removal) There are no particular restrictions on the means of removing the film; for example, it can be removed manually with tweezers or automatically with a robotic arm. As mentioned above, since the film surface is treated with an adhesive coating, the film inside the first through-hole and on the second sheet can be easily removed from the second sheet.

[0060] (Arrangement of window components) The window member is positioned within the first through-hole and on the surface of the second sheet that has adhesive. Furthermore, the step of arranging the window member preferably includes arranging the window member within the first through-hole and on the surface of the second sheet that has adhesive, such that when the polished surface is the upper surface and the side of the second sheet opposite to the side bonded to the first sheet is the lower surface, the uppermost part of the window member is lower than the polished surface. By having the uppermost part of the window member lower than the polished surface, it is possible to prevent scratches on the surface of the workpiece caused by the window member. Furthermore, the process of arranging the window members preferably includes arranging the window members such that, when the polished surface is the upper surface and the side of the second sheet opposite to the side bonded to the first sheet is the lower surface, the top of the window member is higher than the bottom of the groove. By having the top of the window member higher than the bottom of the groove, polishing debris on the window member can be discharged into the groove, and light transmittance can be maintained.

[0061] <2. Pressing Process> The method of the present invention may further include the steps of: placing the polishing pad obtained after the step of arranging the window member on the lower platen 16 of a press machine having an upper platen 17 and a lower platen 16; placing a spacer 15 of a predetermined thickness on the lower platen 16 and around the polishing pad 1; and pressing (pressing 18) the polishing pad with the press machine (Figures 4, 5, and 6). At this time, the upper platen 17 of the press machine presses the polishing pad to the position of the spacer by pressing 18. As illustrated in Figure 4, by placing the polishing pad on the lower platen of the press machine and pressing the polishing pad to the position of the spacer with the upper platen of the press machine, the polishing pad before pressing shown in Figure 5 is compressed in the thickness direction to the polishing pad during pressing shown in Figure 6. There are no particular restrictions on the size of the lower platen and upper platen of the press machine as long as they are large enough to press the entire polishing pad. When the polishing pad is placed on the lower platen of the press machine, it is preferable that it is positioned so that it does not extend beyond the lower platen of the press machine. It is preferable that the press platen is positioned so that the polishing pad does not protrude from the press platen during pressing.

[0062] The thickness S of the spacer used during pressing is within the range of the thickness of the second sheet ≤ S ≤ (H-Tave1). If the spacer thickness S is less than the thickness of the second sheet, the amount of compression will be too large, increasing the risk that the adhesive of the second sheet will squeeze out onto the window material, hindering light transmission. In addition, there is a risk that the pad will be crushed, making it impossible to obtain the desired foam shape and, consequently, polishing performance (problems such as scratches may occur). Furthermore, even after being released from compression after pressing, the thickness of the polishing pad (first sheet) will not recover sufficiently, resulting in a smaller depth from the polishing surface to the top of the window, which can shorten the product life of the pad. If the spacer thickness S exceeds H-Tave1, the press platen will have difficulty contacting the surface of the window material, preventing air from escaping between the window and the adhesive surface. This can lead to insufficient adhesion between the window and the adhesive surface, causing slurry to seep in and potentially causing the window material to peel off. In contrast, if the spacer thickness S is within the above range, the leakage of adhesive and the crushing of the pad are less likely to occur. Furthermore, while the average depth from the polished surface to the top surface of the window member remains unchanged before and after pressing, the difference between the maximum and minimum depths from the polished surface to the top surface of the window member becomes sufficiently small. This has the advantage of reducing in-plane variation in the contact surface with the workpiece from the initial stages of polishing, thus minimizing uneven wear. Furthermore, in the pressing process, it is preferable to press the polishing pad with a press machine so that |Tave1-Tave2| (where || represents the absolute value) is ≤40 μm. It is more preferable that |Tave1-Tave2| is ≤30 μm, even more preferable that it is ≤25 μm, even more preferable that it is ≤20 μm, and even more preferable that it is ≤18 μm or less. Here, S is the thickness of the spacer, H is the thickness of the polishing pad before pressing, Tave1 is the average depth from the polishing surface to the top surface of the window member before pressing, and Tave2 is the average depth from the polishing surface to the top surface of the window member after pressing (the polishing pad after being released from pressure). For example, in the case of a polishing pad with three window members, H, Tab1, and Tab2 can be determined as follows. H: The thickness of the polishing pad was measured using a Shopper-type thickness measuring instrument (pressure surface: circular with a diameter of 1 cm) in accordance with the Japanese Industrial Standard (JIS K 6505), and was defined as H. Tave1: For each of the three window components before pressing, the depth from the polished surface to the top surface of the window component was measured using a depth gauge at four locations on the outer circumference of the top surface of the window component and one location in the center. The depths at 15 locations were measured, and the arithmetic mean was calculated to determine Tave1. Tave2: For each of the three window members after pressing, the depth from the polished surface to the top surface of the window member was measured using a depth gauge at four locations on the outer periphery of the top surface of the window member and one location in the center. The depths at 15 locations were measured, and the arithmetic mean was calculated to determine Tave2. The polishing pad after pressing preferably has a Tmax2-Tmin2 of 18 μm or less, more preferably 15 μm or less, even more preferably 13 μm or less, even more preferably 10 μm or less, even more preferably 8 μm or less, and even more preferably 6 μm or less. In the pressing process, it is preferable that (Tmax2-Tmin2) / (Tmax1-Tmin1) before and after pressing be 0.5 or less, more preferably 0.45 or less, even more preferably 0.4 or less, even more preferably 0.3 or less, and even more preferably 0.2 or less.

[0063] The pressing pressure applied by the press machine is 0.8 MPa or less, preferably 0.1 to 0.6 MPa, more preferably 0.1 to 0.5 MPa, even more preferably 0.1 to 0.4 MPa, even more preferably 0.2 to 0.4 MPa, and most preferably 0.3 MPa. The pressing time using the press machine should be 10 seconds or less, preferably 3 to 7 seconds, more preferably 4 to 6 seconds, and most preferably 5 seconds. It is also desirable to use the press machine at room temperature without heating it. Furthermore, the thickness S of the spacer may be within the range of window member thickness × 0.7 ≤ S ≤ (H-Tave1), or within the range of window member thickness × 0.75 ≤ S ≤ (H-Tave1). Also, the thickness S of the spacer (unit: mm) may be within the range of window member thickness (unit: mm) - 0.3 ≤ S ≤ (H-Tave1), or within the range of window member thickness (unit: mm) - 0.2 ≤ S ≤ (H-Tave1), or within the range of window member thickness (unit: mm) - 0.1 ≤ S ≤ (H-Tave1). Furthermore, the thickness S of the spacer may be within the range of (thickness of the second sheet + thickness of the window member) × 0.3 ≤ S ≤ (H-Tave1), or within the range of (thickness of the second sheet + thickness of the window member) × 0.4 ≤ S ≤ (H-Tave1). The press process reduces variations in the in-plane thickness of the polished layer and corrects irregularities in the adhesive layer. In addition, air pockets between the window member and the second sheet are released, and the window member is firmly fixed to the surface of the second sheet.

[0064] <Second aspect> A method for manufacturing a polishing pad according to a second aspect of the present invention is: A step of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet, A step of forming a first through hole that penetrates the first sheet in the thickness direction from the polished surface to the opposite surface, A step of bonding the first sheet and the second sheet together such that the opposite side of the first sheet and the side of the second sheet having adhesive face each other. A step of placing a film in the first through-hole of the first sheet to which the second sheet has been bonded, wherein the film is a colored film and has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side. A step of acquiring positional information of the first through hole, A step of forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction, based on the acquired position information, wherein the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. The steps of removing the film after the formation of the second through-hole and placing the window member inside the first through-hole and on the surface of the second sheet having adhesive, This is a method for manufacturing polishing pads, including [the specified component]. In the second embodiment of the method for manufacturing a polishing pad, the steps and components can be the same as those described in the first embodiment, particularly in "1. Step of preparing the polishing pad." For example, the manufacturing method further includes a step of preparing a cutting apparatus comprising: an imaging unit that photographs the first sheet from above the polishing surface of the first sheet when the polishing surface of the first sheet is facing upward; a control unit that identifies the position of the first through-hole from the image captured by the imaging unit and, based on the information of the identified position of the first through-hole, commands the first through-hole to form a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction; and a hole forming unit that forms the second through-hole according to the command of the control unit. Furthermore, the step of acquiring the position information may include the control unit identifying the position of the first through-hole from the image captured by the imaging unit. In the second embodiment of the manufacturing method, by manufacturing the polishing pad using a colored film, the position of the first through-hole can be easily identified, and the second through-hole can be formed within the first through-hole based on that positional information. As a result, a polishing pad with an endpoint detection window can be manufactured simply and efficiently, reducing the effort required for manual operation. Furthermore, the impact of errors caused by manual operation can be reduced, improving the yield. In addition, by using a film, dust and dirt can be prevented from adhering between the window member and the exposed portion of the second sheet during the manufacturing of the polishing pad, thereby reducing the risk of the window member peeling off.

[0065] <How to use> When using a polishing pad manufactured by the method of the present invention, the polishing pad is mounted on the polishing platen of the polishing machine so that the polishing surface of the first sheet faces the workpiece. Then, while supplying slurry, the polishing platen is rotated to polish the workpiece surface. Due to the centrifugal force at this time, polishing debris generated during the polishing process and entering the first through-hole is moved to the side of the first through-hole. As a result, polishing debris is less likely to accumulate near the center of the window member, making it possible to detect light over a long period of time. Examples of objects to be polished using the polishing pads manufactured by the method of the present invention include bare silicon and semiconductor devices. Among these, the polishing pads manufactured by the method of the present invention are particularly suitable and preferred for polishing semiconductor devices, especially for finish polishing.

[0066] By using a polishing pad manufactured by the method of the present invention, for example, light is irradiated onto a substrate from a light source through a window member, and interference signals generated by reflection from the surface of the substrate are analyzed. This allows for the optical detection of the surface characteristics and the point at which a planar state is reached in an object to be polished, such as a semiconductor wafer, while simultaneously polishing the object.

[0067] (advantage) According to a first aspect of the present invention, by placing a spacer of a predetermined thickness around the polishing pad and pressing it, it is possible to prevent the polishing pad from being crushed while increasing the adhesion between the back surface of the window member of the polishing pad with an endpoint detection window (window member) and the adhesive surface of the second sheet. As a result, it is possible to manufacture a polishing pad in which the window member is less likely to peel off from the polishing pad. Furthermore, since the window member is fixed in close contact with the adhesive surface, the seepage of slurry can also be suppressed. Moreover, problems of uneven wear during polishing are less likely to occur. Furthermore, in the first aspect of the present invention, the depth variation from the polished surface to the top surface of the window member can be reduced between lots and within the polishing pad by the press treatment, thereby stabilizing the quality of light transmittance. Moreover, since the window member can be installed flat, slurry and polishing debris are smoothly discharged by the centrifugal force during polishing, and slurry and polishing debris are less likely to remain on the surface of the window member. Furthermore, by manufacturing the polishing pad using a colored film, the position of the first through-hole can be easily identified, and the second through-hole can be formed within the first through-hole based on the positional information. This allows for the simple and efficient manufacturing of polishing pads with endpoint detection windows, reducing the effort required for manual operation. In addition, the impact of errors caused by manual operation can be reduced, improving yield. Moreover, by using a film, dust and dirt can be prevented from adhering between the window member and the exposed portion of the second sheet during the manufacturing of the polishing pad, further reducing the risk of the window member peeling off. According to a second aspect of the present invention, a polishing pad equipped with an endpoint detection window can be manufactured efficiently using a simpler method than conventional methods. Furthermore, in the method of the present invention, after the first sheet and the second sheet are bonded together, the film is kept in the first through-hole until the window member is placed, thereby reducing the risk of dust and dirt adhering to the adhesive surface of the second sheet exposed in the first through-hole. This reduces the problem of the window member peeling off from the polishing pad during the processing of the workpiece. Furthermore, by photographing the first sheet with the imaging unit and determining the position of the first through-hole from the image, the control unit can accurately and efficiently create the second through-hole within the first through-hole when viewed in the thickness direction from the polished surface, based on this position information. [Examples]

[0068] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0069] [Example 1] A resin-containing solution was obtained by adding 60 parts by mass of DMF and 5 parts by mass of water to 100 parts by mass of a solution containing 30 parts by mass of a polyester-based polyurethane resin with a 100% modulus of 7.8 MPa and 70 parts by mass of DMF, and then mixing the mixture. The obtained resin-containing solution was filtered to remove insoluble components. The solution was cast onto a polyester sheet using a knife coater to ensure a uniform coating thickness. The polyester sheet with the cast resin-containing solution was then immersed in a solidification bath (solidification liquid: water) to solidify the resin-containing solution. After solidification, the polyester sheet was peeled off, washed, and dried to obtain a first polyurethane sheet. The surface of the obtained first sheet was buffed to a thickness of 1.07 mm. A PET resin substrate with a thickness of 0.188 mm was then bonded to the side opposite the buffed surface with adhesive. The surface of the first sheet was embossed to create a grid pattern of grooves with a rectangular cross-section, a groove width of 1 mm, a groove spacing of 4 mm, and a groove depth of 0.7 mm. The grooved first sheet was cut into 800 mm squares and placed in a predetermined position on a cutting machine (hole forming section) with the grooved side facing upwards. First, drawing data in which circles with a diameter of 25 mm are arranged at 120° intervals on a circle with a diameter of 381 mm was input into a personal computer (control unit). Then, the input data from the personal computer was output to a linked cutting machine, and the first through-holes were created by cutting. Double-sided tape (second sheet (double-sided adhesive tape with polyethylene terephthalate core material), 0.242 mm) with release paper on one side was attached to the side of the first sheet of resin substrate that was not bonded using a laminating machine. After the first sheet was placed again in the designated position on the cutting machine, a film made of release paper cut into a 24 mm diameter circle by the cutting machine was fitted into the three first through-holes on the adhesive surface exposed at the first through-holes. The entire first sheet was photographed with a camera mounted above the first sheet, and the position information of the first through-holes was obtained from the color intensity of the first sheet and the film. A second through-hole with a diameter of 9 mm was created at the center of the first through-holes by cutting. At this time, the program was designed so that the center of the first through-hole and the center of the second through-hole were the same. Furthermore, a center position equidistant from the three first through-holes was identified from the position coordinates of the first through-hole, and the pad was cut using a cutting machine into a circle with a diameter of 762 mm centered at that position.As a window component, a 0.4 mm thick acrylic sheet with a roughened surface was prepared and cut to a diameter of 24 mm using a cutting machine. The film inside the first through-hole was removed and the window component was fitted so that the roughened surface was facing upwards. The first sheet was placed in a designated position on a press machine (a device used for embossing), and 0.3 mm thick spacers were placed at the four corners of the press machine. The entire pad was pressed with a pressure of 0.3 MPa for 5 seconds to press the window component into place, thereby manufacturing an abrasive pad with a window component.

[0070] [Example 2] A polishing pad with a window component was manufactured in the same manner as in Example 1, except that the thickness of the first sheet after buffing was 1.28 mm, the 0.188 mm PET base material was replaced with a 0.678 mm polyurethane resin-impregnated nonwoven fabric base material, the thickness of the acrylic plate serving as the window component was set to 0.8 mm, and the thickness of the spacer was set to 1.5 mm.

[0071] [Comparative Example 1] The polishing pad was manufactured in the same manner as in Example 2, except that the window component was not pressed using a press machine after being fitted in place.

[0072] [Comparative Example 2] The polishing pad was manufactured in the same manner as in Example 1, except that the pressing was performed without using a spacer.

[0073] [Comparative Example 3] The polishing pad was manufactured in the same manner as in Example 1, except that the thickness of the spacer was set to 1.7 mm.

[0074] [Comparative Example 4] A polishing pad was manufactured in the same manner as in Example 2, except that the press pressure was set to 1.0 MPa.

[0075] We examined the appearance defects (pad crushing, adhesive overflow, air trapped between the window member and the adhesive surface) of Examples 1 and 2 and Comparative Examples 1 to 4, as well as the average depth from the polished surface to the top of the window before and after pressing, and the difference between the maximum and minimum depths from the polished surface to the top of the window before and after pressing. The difference between the maximum and minimum depths from the polished surface to the top of the window indicates the degree of variation in the depth from the polished surface to the top of the window; a smaller difference between the maximum and minimum depths indicates less variation and is preferable. H, Tab1, Tab2, and Tmax were calculated as follows. H: The thickness of the polishing pad was measured using a Shopper-type thickness measuring instrument (pressure surface: 1 cm diameter circle) in accordance with the Japanese Industrial Standard (JIS K 6505). Specifically, three 10 cm x 10 cm sample pieces were prepared from the first sheet remaining after cutting the polishing pad in a circular shape during the cutting process. After setting each sample piece in the designated position on the thickness measuring instrument, the pressure surface with a load of 100 g / cm² was placed on the surface of the sample piece, and the thickness was measured after 5 seconds. The thickness was measured at 5 points on each sample piece, and the arithmetic mean was calculated, and then the arithmetic mean of the three sample pieces was calculated. If it is difficult to obtain three 10 cm x 10 cm sample pieces due to the size of the polishing pad, the thickness may be measured at 15 points within the polishing pad, and the arithmetic mean may be calculated to determine the thickness of the polishing pad. Tave1: For each of the three window components before pressing, the depth from the polished surface to the top surface of the window component was measured using a depth gauge at four locations on the outer circumference of the top surface of the window component and one location in the center. The depths at 15 locations were measured, and the arithmetic mean was calculated to determine Tave1. Tave2: For each of the three window members after pressing, the depth from the polished surface to the top surface of the window member was measured using a depth gauge at four locations on the outer periphery of the top surface of the window member and one location in the center. The depths at 15 locations were measured, and the arithmetic mean was calculated to determine Tave2. When calculating Tmax1:Tave1, we determined the largest value among the 15 depths from the polished surface to the top surface of the window member. When calculating Tmin1:Tave1, we determined the smallest value among the 15 depths from the polished surface to the top surface of the window member. When calculating Tmax2:Tave2, we determined the largest value among the 15 depths from the polished surface to the top surface of the window member. The smallest value among the 15 depths from the polished surface to the top surface of the window member was determined when calculating Tmin2:Tave2.

[0076] [Table 1]

[0077] In the table, cosmetic defects were evaluated based on the presence or absence of air trapped between the adhesive surface of the exposed portion of the second sheet and the window member, the adhesive overflowing into the second through-hole, and the pad being crushed (air bubbles inside the pad being crushed by pressing, and remaining crushed after pressing without fully returning to their original shape). A cosmetic defect was determined if one or more of these were present.

[0078] In Comparative Example 1, where no pressing was performed, the maximum and minimum depths from the polished surface to the window surface were large at 30 μm, and air existed between the back surface of the window member and the adhesive surface of the exposed portion of the second sheet, meaning the window member was not in close contact with the exposed portion. In this case, the slurry seeped between the window member and the exposed portion during polishing, making the window member prone to peeling off. In Comparative Example 2, where pressing was performed without using a spacer, the window member was pressed too hard by the press machine, causing adhesive to ooze out onto the inside of the second through-hole, which is the light-transmitting part. This hindered light transmission and was undesirable. In Comparative Example 3, where the spacer thickness was large and the press machine's sinking depth was small, the window member did not come into contact with the upper platen, and air was trapped between the window member and the adhesive surface. In this case, as in Comparative Example 1, the window member was more likely to peel off during polishing. In Comparative Example 4, where the pressing pressure was high, the change in Tave (Tave1-Tave2) was large at 53 μm, and the depth from the polished surface after pressing to the top of the window was extremely small compared to before pressing, indicating pad deformation. The polishing pad in Comparative Example 4, which showed pad deformation, has the disadvantage of having a reduced pad thickness and a shorter product life than usual. In addition, there are problems such as an increase in density compared to usual and an increased likelihood of polishing scratches due to reduced compressive recovery due to plastic deformation. On the other hand, in Examples 1 and 2, the change in Tave (Tave1-Tave2) was 9 μm and 16 μm, respectively, indicating small variation in the depth from the polished surface to the window surface before and after pressing. The range between the maximum and minimum depths from the polished surface to the window surface was reduced by pressing, thus minimizing depth variation. Furthermore, no cosmetic defects such as air trapped between the adhesive surface of the exposed portion and the window member, adhesive overflow into the second through-hole, or pad deformation were observed. Therefore, it was determined that the pad was practical for polishing, and the durability performance (anti-peeling performance) of the window member was further tested.

[0079] <Window component durability verification test> To confirm the durability of the window adhesion, the pad from Example 1 was subjected to an accelerated dressing test under a high dressing pressure condition of 60N, which is six times the normal pressure condition, until the pad was worn down by 600μm. (Dress requirements) Polishing machine used: Speedfam, product name "FAM-12BS" Plate rotation speed (scratching pad rotation speed): 30 rpm Slurry: Pure water Flow rate: 80ml / min Dresser: 3M diamond dresser, model number "A188" Dresser rotation speed: 30 rpm Dressing pressure: 60N

[0080] When the polishing pad was worn down to 600 μm during the accelerated test, the upper part of the window component approached the polishing surface, which could cause the window component surface to come into contact with the dresser. In fact, scratches caused by contact with the dresser were observed on the surface of the window component in Example 1 after the test. However, even when the pad was worn down beyond its normal usage limit under such high pressure and came into contact with the dresser, the polishing pad in Example 1 did not cause delamination of the window component, demonstrating that the window component remained sufficiently fixed. Furthermore, the entire polishing pad after dressing (four locations with diameters differing by 45 degrees, i.e., areas along lines in the north-south, northeast-southwest, east-west, and southeast-northwest directions relative to the pad center (Line A, Line B, Line C, Line D)) and an area within a radius of 70 mm from the center of the endpoint detection window (four locations with diameters differing by 45 degrees, i.e., areas within a radius of 140 mm along lines in the north-south, northeast-southwest, east-west, and southeast-northwest directions relative to the window center (Line A, Line B, Line C, Line D)) were observed using a laser microscope (VK-X1000, KEYENCE), and the height information profile was measured based on the obtained laser images (Figures 8-11). As a result, no abnormal irregular shapes were observed in the profile (≒roughness curve) of the entire pad or around the window member, and the pad did not experience uneven wear due to the window member. Figure 8 shows the overall pad thickness of the pad in Example 1. Figures 9-11 show the pad thickness around each of the three window members of the polishing pad in Example 1. From Figure 8, it can be seen that there are no abnormal irregularities on the entire pad of Example 1. From Figures 9-11, it can be seen that there are no abnormal irregularities around the window members of Example 1. [Industrial applicability]

[0081] According to the present invention, the adhesion between the back surface of the window member of the polishing pad with an endpoint detection window (window member) and the adhesive surface of the second sheet can be improved without the pad being significantly crushed when pressed. As a result, it is possible to manufacture a polishing pad in which the window member is less likely to peel off from the polishing pad. Furthermore, according to the present invention, a polishing pad with an endpoint detection window can be manufactured simply and efficiently with reduced manual operation effort. Therefore, the method of the present invention is extremely useful in industry. [Explanation of Symbols]

[0082] 1… Polishing pad 2…First sheet 3…Second seat 4…Window components 4'...Top of the window component 5…First through hole 5'...Outer periphery of the first through hole 6…Second through hole 6'...Outer periphery of the second through hole 7...Exposed part 8…Groove 8'...Bottom of the groove 9…Object to be polished 10...polishing waste 11... Centrifugal force 12…film 13...polishing layer 14...Base material layer 15…Spacer 16…Press machine lower surface plate 17…Press plate on press machine 18...Pressure

Claims

1. A polishing pad comprising a first sheet having a first through hole, a second sheet having a second through hole, and a window member, The first sheet has a polishing surface for polishing the object to be polished, The second sheet is bonded to the side of the first sheet opposite to the polished surface. The second through-hole is formed such that, when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. When the polished surface is considered the upper surface and the side of the second sheet opposite to the side bonded to the first sheet is considered the lower surface, the window member is positioned within the first through-hole and on the second sheet such that the uppermost part of the window member is lower than the polished surface. The process of preparing the polishing pad, and A process of pressing the polishing pad with a press machine, which has an upper press machine and a lower press machine, by placing the polishing pad on the lower press machine, placing a spacer of a predetermined thickness around the polishing pad on the lower press machine, and pressing the polishing pad with the press machine. A method for manufacturing an abrasive pad, including, The thickness S of the spacer is within the range of the thickness of the second sheet ≤ S ≤ (H - Tave 1), and the press pressure is 0.8 MPa or less. The aforementioned manufacturing method. (Here, S is the thickness of the spacer, H is the thickness of the polishing pad before pressing, and Tab1 is the average depth from the polishing surface before pressing to the top surface of the window member.)

2. The manufacturing method according to claim 1, comprising pressing the polishing pad with a press machine so that |Tave1 - Tave2| ≤ 40 μm. (Here, Tab 1 is the average depth from the polished surface before pressing to the top surface of the window member, and Tab 2 is the average depth from the polished surface after pressing to the top surface of the window member.)

3. The process of preparing the polishing pad involves the following steps: A step of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet, A step of forming a first through hole that penetrates the first sheet in the thickness direction from the polished surface to the opposite surface, A step of bonding the first sheet and the second sheet together such that the opposite side of the first sheet and the side of the second sheet having adhesive face each other. A step of placing a film in the first through-hole of the first sheet to which the second sheet has been bonded, wherein the film is a colored film and has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side. A step of acquiring positional information of the first through hole, A step of forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction, based on the acquired position information, wherein the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. The steps of removing the film after the formation of the second through-hole and placing the window member inside the first through-hole and on the surface of the second sheet having adhesive, The manufacturing method according to claim 1, including

4. The aforementioned film is a film having a color different from the color of the polished surface of the first sheet. The manufacturing method according to claim 3, wherein the step of acquiring the position information includes determining the position of the first through hole by utilizing the difference in color between the film and the polished surface.

5. With the polishing surface of the first sheet facing upwards, the camera unit photographs the first sheet from above the polishing surface of the first sheet, A control unit that identifies the position of the first through-hole from the image captured by the imaging unit, and based on the information of the identified position of the first through-hole, commands the first sheet to form a second through-hole that penetrates the second sheet within the first through-hole when viewed from the polishing surface side in the thickness direction, A hole forming unit that forms the second through hole in accordance with the command of the control unit, The process further includes a step of preparing a cutting machine equipped with, The manufacturing method according to claim 3, wherein the step of acquiring the position information includes the control unit identifying the position of the first through hole from the image captured by the imaging unit.

6. The manufacturing method according to claim 5, wherein the step of acquiring the position information includes the control unit identifying the position of the film by identifying the difference in color between the film and the polished surface in the image captured by the imaging unit.

7. The manufacturing method according to claim 5, wherein the step of forming the second through-hole includes, based on the acquired positional information of the first through-hole, the hole forming unit forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction.

8. The process of forming two through holes is as follows: The manufacturing method according to claim 3 or 5, comprising forming the second through-hole based on the positional information of the first through-hole, such that the center of the first through-hole and the center of the second through-hole are substantially the same when the first sheet is viewed from the polished surface side in the thickness direction.

9. A step of obtaining information on positions (equally distanced positions) that are at an equal distance from the center of all first through holes when the first sheet is viewed from the polished surface side in the thickness direction, based on the position information of the first through holes, and Based on the equidistant position information, the process involves cutting the first sheet, which has been bonded to the second sheet so as to enclose the first through-hole with an arbitrary radius centered on the equidistant position, into a circular shape. The manufacturing method according to claim 3 or 5, further comprising:

10. The manufacturing method according to claim 3 or 5, wherein the shape of the first through-hole and the shape of the second through-hole are both circular when viewed in the thickness direction from the polishing surface side of the polishing pad.

11. The manufacturing method according to claim 3 or 5, wherein the equivalent circular diameter of the first through hole is 5 to 30 mm larger than the equivalent circular diameter of the second through hole.

12. The manufacturing method according to claim 3 or 5, further comprising the step of providing grooves (for example, embossed grooves) on the polished surface of the first sheet.

13. The step of arranging the window member is: The manufacturing method according to claim 3 or 5, comprising arranging the window member such that, when the polished surface is the upper surface and the side of the second sheet opposite to the side adhering to the first sheet is the lower surface, the uppermost part of the window member is higher than the lowermost part of the groove.

14. A method for manufacturing an abrasive pad, comprising the following steps: A step of preparing a first sheet having a polishing surface and a surface opposite to the polishing surface (opposite surface), and a second sheet having an adhesive on at least one surface of the first sheet, A step of forming a first through hole that penetrates the first sheet in the thickness direction from the polished surface to the opposite surface, A step of bonding the first sheet and the second sheet together such that the opposite side of the first sheet and the side of the second sheet having adhesive face each other. A step of placing a film in the first through-hole of the first sheet to which the second sheet has been bonded, wherein the film is a colored film and has substantially the same shape as the first through-hole when the first sheet is viewed in the thickness direction from the polished surface side. A step of acquiring positional information of the first through hole, A step of forming a second through-hole that penetrates the second sheet within the first through-hole when the first sheet is viewed from the polishing surface side in the thickness direction, based on the acquired position information, wherein the second through-hole is formed such that when the first sheet is viewed from the polishing surface side in the thickness direction, the outer periphery of the second through-hole is covered by the outer periphery of the first through-hole. The steps of removing the film after the formation of the second through-hole and placing the window member inside the first through-hole and on the surface of the second sheet having adhesive, A manufacturing method that includes this.

15. With the polishing surface of the first sheet facing upwards, the camera unit photographs the first sheet from above the polishing surface of the first sheet, A control unit that identifies the position of the first through-hole from the image captured by the imaging unit, and based on the information of the identified position of the first through-hole, commands the first sheet to form a second through-hole that penetrates the second sheet within the first through-hole when viewed from the polishing surface side in the thickness direction, A hole forming unit that forms the second through hole in accordance with the command of the control unit, The process further includes a step of preparing a cutting machine equipped with, The manufacturing method according to claim 14, wherein the step of acquiring the position information includes the control unit identifying the position of the first through hole from the image captured by the imaging unit.

16. The manufacturing method according to claim 15, wherein the step of acquiring the position information includes the control unit identifying the position of the film by identifying the difference in color between the film and the polished surface in the image captured by the imaging unit.

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