Adhesive sheet for fixing polishing pad, polishing pad with adhesive layer a, and method for fixing polishing pad to polishing plate

Abstract

Provided is an adhesive sheet (1) for fixing a polishing pad with a release sheet FA, the adhesive sheet (1) being provided with an adhesive layer A on one surface of a sheet-like base material (F) and an adhesive layer B on the other surface, with the other surface of the adhesive layer A being in contact with the release sheet FA, wherein the outer surface of the release sheet FA has irregularities, the shape in a plan view is regular and fixed, the average height Rc of the irregularities on the front surface is 5-25 μm, the material of the release sheet FA is a plastic film, the Bekk smoothness of the outer surface determined under a specific condition 1 is 0.1-30 seconds, and the Bekk smoothness of the outer surface determined under a specific condition 2 is 1-500 seconds, thereby providing a method for fixing a polishing pad to a polishing plate.

Description

Adhesive sheet for fixing polishing pad, polishing pad with adhesive layer A, and method for fixing polishing pad to a surface plate.

[0001] This disclosure relates to an adhesive sheet for fixing a polishing pad with a release sheet FA, and to an adhesive sheet for fixing a polishing pad with a release sheet FA and a release sheet FB. It also relates to a polishing pad with a release sheet FA and an adhesive layer A. Furthermore, it relates to a method for fixing a polishing pad to a surface plate via an adhesive sheet.

[0002] In recent years, semiconductor development has demanded higher integration and higher quality, and the wafers used as materials also require higher polishing precision. In addition to simple grinding with abrasive grains, there are methods that use chemical reactions, such as CMP (Chemical Mechanical Polishing), to alter only the surface and polish it. Even in CMP, development is progressing to obtain polished surfaces that are even smoother than before. When attaching the polishing pad to the surface plate, a double-sided adhesive sheet is used. Specifically, one side of the double-sided adhesive sheet is attached to one side of the polishing pad (the side opposite to the side to be polished), a polishing pad with a single-sided adhesive layer is prepared in advance, and the adhesive layer of the single-sided adhesive pad is attached to the surface plate.

[0003] Various types of adhesive sheets have been proposed for fixing polishing pads (e.g., Patent Documents 1-3).

[0004] Japanese Patent Publication No. 2011-122069, Japanese Patent Publication No. 2011-168714, Japanese Patent Publication No. 2012-057135

[0005] Polishing pads are required in various forms depending on the polishing stage, and polishing pads used for the final finishing stage, in particular, are increasingly complex in structure, with multiple layers having varying hardnesses and thicknesses. The more complex the structure of the polishing pad, the more difficult it becomes to attach it to the polishing plate. When attaching a highly multi-layered, thick polishing pad with a single-sided adhesive layer to a polishing plate, it is often necessary to temporarily attach it, check the position, peel it off, and reattach it to adjust the position. From the standpoint of improving productivity, it is desirable to minimize the time and number of repositioning adjustments. In terms of ease of repositioning, using an adhesive layer with low adhesive strength is effective. However, the adhesive layer that fixes the polishing pad to the polishing plate requires strong adhesive strength and cohesive force (holding force) that can withstand polishing sufficiently.

[0006] Furthermore, even if a polishing pad with an adhesive layer on one side can be quickly and temporarily fixed to the target position on the surface plate, there is a problem of air trapped between the surface plate and the adhesive layer when the polishing pad is firmly fixed to the surface plate using rollers or a press. If air remains locally trapped between the surface plate and the adhesive layer, the parallelism between the outermost surface of the polishing pad and the surface plate is impaired, making it impossible to polish the workpiece smoothly with high precision, thus affecting the polishing accuracy. One possible method to suppress air trapped air is to create grooves on the surface of the adhesive layer on the side that contacts the surface plate to serve as air passages. However, even if air passages are provided, when the polishing pad is firmly fixed to the surface plate, the air passages may be blocked by the soft adhesive layer, making it impossible to completely remove the voids, or it may take a long time for the air to escape, which can reduce the semiconductor production speed. In addition, in CMP, the polishing pad attached to the surface plate is reused 100 to 1000 times, so maintaining the polishing quality (amount of polishing) even after repeated use is considered the most important factor in terms of manufacturing costs.

[0007] The adhesive layer of the double-sided adhesive sheet used to fix the polishing pad to the surface plate requires strong adhesive strength, cohesive force (holding force) to withstand the shear force applied during the polishing process, and chemical resistance to strong alkalis and strong acids from the polishing solutions used during polishing. In particular, CMP often uses strong alkaline polishing solutions, so strong alkali resistance is required.

[0008] This disclosure is made in view of the above background, and aims to provide a double-sided adhesive sheet for fixing polishing pads to a surface plate, which is suitable for high-precision CMP processing, is easy to adjust the position by repositioning, has excellent air release properties, has excellent adhesive properties, and exhibits stable polishing performance even after repeated polishing. Furthermore, it aims to provide a polishing pad with a release sheet FA and an adhesive layer A to obtain a polishing pad that is attached to a surface plate and exhibits stable polishing performance even after repeated polishing use. In addition, it aims to provide a method for fixing a polishing pad to a surface plate via an adhesive sheet.

[0009] After diligent research by the present inventors, we have found that the problems of this disclosure can be solved in the following embodiments, and have completed this disclosure.

[0010] [1]: An adhesive sheet for fixing a polishing pad with a release sheet FA, wherein the sheet-like substrate has an adhesive layer A on one side and an adhesive layer B on the other side, and the surface of the adhesive layer A that is not in contact with the sheet-like substrate is in contact with the release sheet FA, wherein the shape of the convex portion on the outer surface of the release sheet FA in plan view is regular and fixed, the average height Rc of the unevenness on the outer surface of the release sheet FA is 5 to 25 μm, the material of the release sheet FA is plastic, the outer surface of the release sheet FA that is not in contact with the adhesive layer A has unevenness, and in a Beck smoothness test, the smoothness of the outer surface of the release sheet FA as determined by the following condition 1 is 0.1 to 30 seconds, and the smoothness of the outer surface of the release sheet FA as determined by the following condition 2 is 1 to 500 seconds. Condition 1: Time until the pressure changes from -50.7 kPa to -48.0 kPa. Condition 2: Time taken for the pressure to change from -50.7 kPa to -29.3 kPa. [2]: The adhesive sheet for fixing a polishing pad with a release sheet FA as described in [1], wherein the outer side of the release sheet FA and the inner side of the release sheet FA are the same shape but inverted. [3]: The adhesive sheet for fixing a polishing pad with a release sheet FA as described in [1] or [2], characterized in that the average height Rc of the surface irregularities on the outer side of the release sheet FA is 5 to 25 μm, and the average height Rc of the surface irregularities on the inner side of the release sheet FA is 5 to 25 μm. [4]: ​​The adhesive sheet for fixing a polishing pad with a release sheet FA as described in any of [1] to [3], characterized in that the thickness of the release sheet FA is 25 to 100 μm.

[0011] [5]: The adhesive sheet for fixing a polishing pad with a release sheet FA according to any one of [1] to [4], characterized in that the difference in cutting levels Rδc of the contour curve of the unevenness on the outer surface of the release sheet FA is 1 to 10 μm. [6]: The adhesive sheet for fixing a polishing pad with a release sheet FA according to any one of [1] to [5], characterized in that the adhesive layer A is an acrylic adhesive layer. [7]: The adhesive sheet for fixing a polishing pad with a release sheet FA according to any one of [1] to [6], which is wound in a roll shape and the length in the width direction of the wound body is 1000 mm or less.

[0012] [8]: An adhesive sheet for fixing a polishing pad with a release sheet FA and a release sheet FB, comprising an adhesive sheet for fixing a polishing pad with a release sheet FA as described in any of [1] to [7] above, wherein the release sheet FB is in contact with the surface of the adhesive layer B that is not in contact with the sheet-like substrate, and the material of the release sheet FB is plastic. [9]: A roll-shaped adhesive sheet for fixing a polishing pad with a release sheet FA and a release sheet FB as described in [8], wherein it is wound in a roll shape and the length in the width direction of the wound body is 1000 mm or less.

[10] : An adhesive sheet for fixing a polishing pad with a release sheet FA and a release sheet FB as described in [8] or [9] above, wherein the length of the short side is 1000 mm or less.

[0013]

[11] : A polishing pad with an adhesive layer, comprising a polishing pad and an adhesive sheet for fixing the polishing pad with a release sheet FA as described in any of [1] to [7] above, wherein the polishing pad and the adhesive layer B are in contact with each other, the polishing pad with a release sheet FA and adhesive layer A.

[0014]

[12] : A method for fixing a polishing pad to a surface plate via an adhesive sheet, characterized by peeling off the release sheet FA from the polishing pad with the release sheet FA and adhesive layer A as described in

[11] , and attaching the adhesive layer A to the surface plate.

[0015] According to this disclosure, a double-sided adhesive sheet for fixing a polishing pad to a surface plate can be provided, which allows for easy repositioning by repositioning, has excellent air release properties, and also exhibits superior adhesive properties and chemical resistance to strong alkalis and strong acids. The adhesive sheet for fixing polishing pads with release sheet FA of this disclosure can improve workability during application and significantly improve polishing accuracy in high-precision CMP processing. Furthermore, the polishing pad with adhesive layer A of this disclosure exhibits the excellent effect of maintaining stable polishing performance even when attached to a surface plate and repeatedly used for polishing.

[0016] Schematic cross-sectional view of an adhesive sheet for fixing a polishing pad with release sheet FA. Schematic cross-sectional view of an adhesive sheet for fixing a polishing pad with release sheet FA and release sheet FB. Schematic cross-sectional view of a polishing pad with release sheet FA and adhesive layer A. Schematic cross-sectional view showing the state in which the polishing pad is fixed to the surface plate via the adhesive sheet. Schematic explanatory diagram showing an example of an adhesive sheet for fixing a polishing pad with a roll-shaped release sheet FA. Schematic explanatory diagram of a measurement sample used in the Beck smoothness test. Schematic explanatory diagram for explaining the Beck smoothness test method. Schematic cross-sectional view to explain an example of surface irregularities (cross-section) of the release sheet FA. Schematic cross-sectional view to explain the surface irregularities of an example of the release sheet in this embodiment. Schematic cross-sectional view to explain the surface irregularities of the release sheet in a comparative example. (a) and (b) are images of the outer surface of the release sheet FA according to an example of the embodiment. Schematic explanatory diagram to explain the measurement method of Rc and Rδc of the outer surface of the release sheet FA. Schematic diagram to explain an example of the "regular" shape of the irregularities (plan view) of the outer surface of the release sheet FA. Cross-sectional view of the X-X' section in Figure 6B. Cross-sectional view of the X-X' section of the laminate of adhesive layer A / sheet-like substrate transferred by the release sheet FA in Figure 6B. Schematic diagram to illustrate an example of a "regular" shape of the surface irregularities (plan view) on the outside of the release sheet FA. Cross-sectional view of the Y-Y' section in Figure 6E. Cross-sectional view of the Y-Y' section of the laminate of adhesive layer A / sheet-like substrate transferred by the release sheet FA in Figure 6E. Schematic diagram to illustrate an example of a "regular" shape of the surface irregularities (plan view) on the outside of the release sheet FA. Explanatory diagram showing an example of an irregular and irregular pattern / design on the surface irregularities (plan view) on the outside of the release sheet FA. Manufacturing process diagram showing an example of a method for forming irregularities on the release sheet FA. Schematic cross-sectional view showing the usage form of the adhesive sheet for fixing the polishing pad with the release sheet FA. Schematic diagram to explain the evaluation method for the bonding workability of this embodiment. Schematic diagram to explain the evaluation method for the air release performance of this embodiment.

[0017] An example of an embodiment applying this disclosure will be described below. In this specification, the numerical values ​​"A to B" refer to values ​​between A and B.

[0018] <Adhesive Sheet for Fixing Polishing Pad with Release Sheet FA, etc.> The adhesive sheet 1 for fixing polishing pad with release sheet FA of the present disclosure has, as shown in Figure 1A, an adhesive sheet 5 for fixing polishing pad (hereinafter also referred to as adhesive sheet 5) having an adhesive layer A on one side of a sheet-like substrate F and an adhesive layer B on the other side. The surface of the adhesive layer A of the adhesive sheet 5 for fixing polishing pad (the side not in contact with the sheet-like substrate F) is covered and protected by the release sheet FA. The contact surface of the release sheet FA with the adhesive layer A corresponds to the release surface. The material of the release sheet FA is a plastic film. The adhesive sheet 1 for fixing polishing pad with release sheet FA can also be provided in a roll form, as shown in Figure 1E, by winding it around a cylindrical member 6 called a core (also called a core material), and covering the surface of the adhesive layer B with the outer surface of the release sheet FA (the side not in contact with the adhesive layer A). As the sheet 1 for fixing the polishing pad with the release sheet FA, for example, it can be wound in a roll shape and the length in the width direction of the winding body can be 1000 mm or less. Note that in Figure 1A and other figures, the surface irregularities of the release sheet FA and adhesive layer A are omitted from the illustration.

[0019] Another embodiment is a form of the adhesive sheet 2 for fixing the polishing pad with a release sheet FA and a release sheet FB, as shown in Figure 1B, which includes a release sheet FB covering the surface of the adhesive layer B. Examples of the polishing pad fixing sheet with a release sheet FA and a release sheet FB include a sheet with a short side length of 1000 mm or less, or a form that is wound in a roll shape and has a widthwise length of 1000 mm or less.

[0020] As shown in Figure 1C, the polishing pad 3 with a release sheet FA and adhesive layer A (hereinafter also simply referred to as polishing pad 3) of this disclosure has a polishing pad PP laminated on the adhesive layer B of the adhesive sheet 1 for fixing the polishing pad with a release sheet FA.

[0021] The polishing pad PP and the surface plate SP are fixed via an adhesive sheet 5. Specifically, the release sheet FA is peeled off from the polishing pad 3 (Figure 1C) with the release sheet FA and adhesive layer A, and the polishing pad 4 with adhesive layer A, with adhesive layer A exposed, is attached to the surface plate SP (Figure 1D). Adhesive layer A of the adhesive sheet 5 is in contact with the surface plate SP, and adhesive layer B is in contact with the polishing pad PP. In other words, the polishing pad PP is fixed to the surface plate SP via the adhesive sheet 5, which has a laminated structure of adhesive layer A / sheet-like base material F / adhesive layer B.

[0022] When attaching the polishing pad PP to the surface plate SP via the adhesive sheet 5, in most cases until now, the polishing pad PP was lightly bent and flexed, and the surface of the polishing pad PP was slowly rubbed from the edge with a roll or squeegee to push out the air from the edge while attaching it. When attaching the adhesive layer A to the surface plate SP, if the adhesive sheet is wrinkled or if uneven force is applied to the adhesive sheet 5, a large localized air pocket will be generated between the surface plate SP and the adhesive layer A. However, recently, polishing pads PP have tended to become thicker, extremely hard, or extremely soft. Polishing pads PP that have become thicker or extremely hard are too rigid, so they cannot be flexed as in the conventional way, and a problem arises in that the rolling roller or squeegee used for rubbing cannot adequately act on the surface of the polishing pad PP. On the other hand, extremely softened PP polishing pads are prone to bending and flexing, making it difficult to maintain a flexible state when working the surface of the polishing pad with a roll or squeegee. In either case, it is not possible to quickly push out the air at the bonding interface or to smooth the entire interface, resulting in large localized air pockets. Furthermore, when working the surface of the PP polishing pad with a roll or squeegee, localized pressure is applied to the surface of the PP polishing pad. Even if the pressure is applied sequentially across the entire surface of the PP polishing pad, there is a requirement to avoid applying too much force to the surface of the PP polishing pad, as it is the surface that will come into contact with the object to be polished.

[0023] The adhesive sheet 1 for fixing the polishing pad with a release sheet FA of this disclosure has an uneven surface on the outer side of the release sheet FA (the surface intended to contact the surface plate SP), which is determined by the Beck smoothness test and surface height described later. The adhesive layer A has the same uneven surface as the outer side of the release sheet FA transferred to it, and the recesses on the surface of the adhesive layer A can be used as ventilation paths (flow channels) to push the air between the surface plate SP and the adhesive layer A outwards from the surroundings or to smooth the entire adhesion interface. As a result, it is possible to suppress and prevent the occurrence of large localized air pockets between the surface plate SP and the adhesive sheet 5 that would impair the parallelism between the surface of the polishing pad PP (the surface in contact with the object to be polished) and the surface plate SP.

[0024] This section describes the Beck smoothness of the outer surface of the release sheet FA. Beck smoothness is specified in JIS P8119:1998. The procedure for the Beck smoothness test is outlined below. (1) The test piece described later is placed on the flat surface of a glass (a ring-shaped glass component with a circular hole in the center connected to a vacuum container) that has been optically planarized. (2) With a pressure of 0.1 MPa applied to a rubber press plate placed on the test piece via a pressure plate, the pressure inside the vacuum container is reduced to -50.7 kPa. (3) Once -50.7 kPa is reached, the pressure reduction is stopped, and atmospheric pressure air is drawn in from between the glass surface and the contact surface of the test piece. Here, the time it takes for the pressure inside the vacuum container to change from -50.7 kPa to -48.0 kPa (condition 1) and from -50.7 kPa to -29.3 kPa (condition 2) is measured, and the permeability of the surface of the adhesive layer A can be evaluated based on these values. In other words, in both conditions 1 and 2, the shorter the time it takes to return to the predetermined pressure, the easier it is for air to circulate.

[0025] The above test specimens were prepared as follows. First, a polyethylene terephthalate (PET) film with a thickness of 100 μm and a double-sided Rc of less than 0.5 μm was attached to the adhesive layer B of the adhesive sheet 1 for fixing the polishing pad with a release sheet FA. This film was then cut into 50 mm squares, and two of these were stacked to obtain a laminate, as shown in Figure 2A. A circular hole 7 with a radius of 5 mm (smaller than the circular hole in the center of the glass member) was made in the center of the obtained laminate to obtain the measurement sample 8. Then, as shown in Figure 2B, the outer surface of the bottommost release sheet FA in the figure was placed on the surface of the glass member G so that the hole 7 of the measurement sample 8 was directly above the circular hole 9 in the center of the glass member G. A rubber press plate E was placed on the top surface of the topmost PET film in the figure, and a pressure of 0.1 MPa was applied via a pressure plate H. The pressure was then reduced by suction from below the circular hole 9 in the center of the glass member G, and the smoothness under conditions 1 and 2 was determined. In the measurement sample 8, two adhesive sheets 1 for fixing the polishing pad with release sheets FA are stacked, so half of the measured value represents the result for one adhesive layer A of the adhesive sheets 1 for fixing the polishing pad with release sheets FA. That is, if the measured value is 2 seconds, the Beck smoothness of the outer surface of the release sheet FA will be 1 second.

[0026] The Beck smoothness of the outer surface of the release sheet FA is important to be 0.1 to 30 seconds under Condition 1, more preferably 0.5 to 20 seconds, particularly preferably 1.0 to 10 seconds, and most preferably 1.5 to 6 seconds. The smoothness under Condition 1 is related to the movement and state of air in the very initial stages when the adhesive layer A contacts the base plate SP, and is mainly related to position adjustment. That is, if the smoothness under Condition 1 is 20 seconds or less, when the adhesive layer A contacts the base plate SP, large localized air pockets are less likely to occur, and the adhesive layer A can adhere tightly to the base plate SP as if being sucked in. When the position of the adhesive layer A in contact with the base plate SP is appropriate and no position adjustment is necessary, if the smoothness under Condition 1 is less than 0.1 seconds, the air permeability is too good, and the position of the adhesive layer A is more likely to shift. In other words, having a smoothness of 0.1 seconds or more under condition 1 makes it easier to maintain the position of the polishing pad 4 with adhesive layer A, which has an adhesive sheet for fixing the polishing pad and is attached to the surface plate SP.

[0027] Furthermore, the Beck smoothness of the outer surface of the release sheet FA is important to be 1 to 500 seconds under condition 2, more preferably 20 to 200 seconds, even more preferably 30 to 150 seconds, and most preferably 40 to 100 seconds. The smoothness under condition 2 is related to the movement and state of air for several minutes to about ten minutes after the adhesive layer A is attached to the base plate SP, and is mainly related to the air release properties of the adhesive interface. If the smoothness under condition 2 is 400 seconds or less, even if localized air pockets occur between the base plate SP and the adhesive layer A, it becomes easier to spread the air evenly across the entire adhesive interface through the recesses of the adhesive interface, or to release air from the outer periphery. If the smoothness under condition 2 is 1 second or more, the adhesive layer A that is in contact with the base plate SP adheres more firmly to the base plate SP. Being within the aforementioned preferred range allows for a smooth, undistorted, and highly adhesive state to the surface plate, while also allowing voids to gradually disappear within several tens of minutes without any special treatment, making it suitable for CMP polishing processes where high precision is required. Being within the aforementioned more preferred range allows for high adhesion while also having vents sufficient to prevent slurry from entering between the adhesive layer A and the surface plate during polishing, thereby suppressing deterioration of the adhesive layer, preventing lifting and swelling, allowing for repeated use of the polishing pad, and reducing variations in the polishing lot.

[0028] Furthermore, the surfaces of the release sheet FB and adhesive layer B (the surfaces that will come into contact with the polishing pad PP) do not need to have any special irregularities. When the polishing pad 3 is attached to the surface plate SP, it is attached by hand, so large localized air pockets tend to form between the adhesive layer A and the surface plate SP. On the other hand, when the polishing pad PP is attached to the adhesive layer B of the adhesive sheet 1 for fixing the polishing pad with the release sheet FA, it is attached mechanically rather than by hand, so unlike when the polishing pad 3 is attached to the surface plate SP, large localized air pockets are unlikely to form in the first place.

[0029] An example of the shape of the surface irregularities (cross-section) of the release sheet FA will be explained using the schematic partial enlarged cross-sectional views in Figures 3A to 3D. Note that the adhesive layer A has a pattern that is an inversion of the outside surface of the release sheet FA transferred onto it, so it has the same shape as the outside surface of the release sheet FA. In the cross-section shown in the figure, the adhesive layer A is in contact with the upper part, and the lower part is the outside of the release sheet FA. For the sake of explanation, the surface of the release sheet FA that is in contact with the adhesive layer A may be called the inside of the release sheet FA, and the surface that is not in contact may be called the outside of the release sheet FA. Even after being bonded to the surface plate SP, the surface of the adhesive layer A is not completely crushed, and reliable ventilation holes are ensured. Therefore, it is preferable that the corners of the protrusions on the outside of the release sheet FA be angular, as shown in Figure 3A, rather than rounded, as shown in Figure 3C. This is because when pressure is applied to the surface of the adhesive layer A corresponding to the shape of the protrusions on the outside of the release sheet FA, the pressure concentrates at the corners of the protrusions, and the angular shape prevents it from being completely crushed and flattened. Furthermore, the larger the contact area ratio between the surface of the adhesive layer A and the surface plate SP, the more the parallelism between the surface plate SP and the polishing pad PP is maintained. Therefore, in order to improve polishing accuracy and suppress variations in the polishing lot, Figure 3A, in which the convex portion on the outside of the release sheet FA is wider than the concave portion (i.e., the convex portion of the adhesive layer A is wider), is preferable to Figure 3B, and Figure 3C is preferable to Figure 3D.

[0030] Therefore, in order to improve air release and alignment without reducing polishing accuracy, it is important that the average height Rc of the roughness curve elements on the outer surface of the release sheet FA (hereinafter abbreviated as average height Rc) is 5 to 25 μm, preferably 7 to 20 μm, and more preferably 10 to 15 μm. Being within this range allows the surface of the adhesive layer A to be reproduced with high accuracy. When the average height Rc of the outer surface of the release sheet FA is 5 μm or more, the recesses become relatively deeper, so the air permeability is improved on the surface of the adhesive layer A in both conditions 1 and 2 of the Beck smoothness test, improving alignment and air release. In particular, it has a significant impact on air release, making it easier to peel the polishing pad PP together with the adhesive sheet 5 from the surface plate SP after polishing is complete. The average height Rc of the outer surface of the release sheet FA is 25 μm or less. When the adhesive layer A, which reproduces such an average height Rc, is attached to the surface plate SP as a polishing pad PP and polished, the uneven shape does not easily affect the outermost surface of the polishing pad PP that comes into contact with the workpiece, resulting in superior polishing accuracy. In addition, the recesses formed on the adhesive surface are less likely to be crushed by the deformation of the adhesive layer that occurs during attachment, and the recesses on the surface of the adhesive layer, which serve as vents, remain uniform without being partially blocked. This makes it easier to remove partially penetrated slurry, improving polishing accuracy. Furthermore, being within the above-mentioned more preferable range is preferable because it maintains the above-mentioned polishing accuracy and air release properties while making the vent size less likely to allow slurry to penetrate. This is preferable because even when polishing lots are repeated (polishing new workpieces without changing the polishing pad), there is less difference in polishing rate (amount of polished material) between polishing lots.

[0031] The shape of the unevenness on the outer surface of the release sheet FA of this disclosure can be more specifically understood from the difference in cutting levels of the contour curve: Rδc, including the roundness and inclination of the protrusions and the spacing of the unevenness. The Rδc of the outer surface 11 of the release sheet FA is preferably 1 to 10 μm, more preferably 2 to 7.5 μm, and even more preferably 4 to 6 μm. The Rδc is the difference in the height direction level that matches any two load length ratios from the load curve (a curve plotting the ratio of the actual length to the measured length in order of height), and in this disclosure, the two load length ratios are defined as 0% and 50%. In particular, Rδc expressed with load length ratios of 0% and 50% indirectly indicates the depth and frequency of the unevenness and the inclination of the protrusions. When the Rδc of the outer surface 11 of the release sheet FA is 1 μm or more, air pockets are less likely to occur in the very early stages of application, and variations between polishing lots (lot variation) are more easily suppressed. In other words, since the adhesive layer A does not adhere very strongly to the surface plate SP, when peeling the adhesive layer A off the surface plate SP after contact, it can be peeled off with little resistance, making position adjustment easier. However, because the adhesive layer A is adhesive, it is thought that it deforms to some extent when it is attached to the surface plate SP. That is, microscopically, it is imagined that the convex parts on the surface of the adhesive layer A are crushed to a small extent during attachment, and the concave parts become relatively shallower. Since the Rδc of the outer surface 11 of the release sheet FA is 10 μm or less, even if the adhesive layer A is crushed when it is strongly attached to the surface plate SP, the concave parts are reliably maintained, thus improving air release.

[0032] Rc and Rδc will be explained using schematic diagrams. Note that the following explanation refers to the lower side of each diagram (the outside of the FA on the adhesive sheet for fixing the polishing pad with the release sheet FA). Figures 3A, 3B, and 3C show cases where Rc is approximately the same. If Figure 3A shows the case where Rδc is between 1 and 10 μm, then in Figure 3B, where the convex portion on the lower surface corresponding to the vent is wider and the concave portion on the lower surface corresponding to the part where the adhesive layer touches the adherend is narrower than in Figure 3A, Rδc will be larger than in Figure 3A. In the case of Figure 3C, Rδc will be even larger than in Figure 3B.

[0033] Rc and Rδc are values ​​measured according to JIS B 0601 (2013), and can specifically be measured using a laser microscope (Keyence VK-X100). An example of an image of the outer surface 11 of the release sheet FA observed with a laser microscope is shown in Figure 5A. In the upper part of Figure 5A, the straight lines are concave, and the triangular areas surrounded by the straight lines are convex, forming a regular and fixed shape in plan view. Specifically, at a magnification of 100x, six consecutive images are taken in both the vertical and horizontal directions of a field of view of approximately 950 μm vertically and 1300 μm horizontally (36 images in total), and the entire observation field is approximately 5700 μm vertically and 7800 μm horizontally. The measurement field is the central area of ​​the entire observation field, approximately 5500 μm vertically and 7500 μm horizontally (see Figure 5B), and measurement lines are set along one and two diagonal directions in the horizontal direction of the measurement field, and Rc and Rδc are measured, and their average values ​​are calculated. If, as shown in Figure 5C, the diagonal of the measurement field of view is located directly above the convex portion, the measurement line should be set to cross as many (e.g., five or more) concave and convex portions as possible, at a position approximately parallel to the diagonal. Similarly, for the lateral measurement line, to avoid measuring only directly above the convex portion, the measurement line should be set to cross as many concave and convex portions as possible, at a position approximately parallel to the lateral direction of the measurement field of view. The same applies to the measurement of Rc, etc., of the release sheet FA, which will be described later.

[0034] Figure 4A shows an image of the cross-sectional shape of the unevenness of the outer surface 11 of the release sheet FA in this disclosure, and Figure 4B shows an image of the cross-sectional shape of the unevenness of the outer surface 11 of the release sheet FA-x in the comparative example, which is a so-called "matte" material. Unlike the unevenness of a so-called "matte" material intended for optical matting, the elements (spacing, depth) of the unevenness on the outer surface of the release sheet FA in this disclosure are significantly larger. Because the elements of the unevenness of a "matte" material are significantly smaller, it is difficult to transfer the unevenness shape of the outer surface of the release sheet FA directly to the adhesive layer A. Even if it were transferred to the adhesive layer A, the height difference of the unevenness and the spacing of the unevenness are larger and the spacing of the unevenness are wider than that of a so-called "matte" material which is good at general optical matting, which is formed by Rc and Rδc in this disclosure on the adhesive layer A. This represents an ideal shape for initial position adjustment during application, air release during application, and fixing the polishing pad parallel and smooth to the surface plate.

[0035] This section describes the "regularity" of the surface irregularities (plan view) on the outer surface of the release sheet FA. Examples of regular patterns and designs on the surface irregularities (plan view) of the outer surface of the release sheet FA in this disclosure include a grid pattern as shown in Figure 6A and a polka dot pattern as shown in Figures 6B and 6E. In the figures, the gray and shaded areas represent recesses. Figure 6B shows a case where the outer surface of the release sheet FA has a regular polka dot pattern consisting of independent circular recesses and continuous protrusions. Figure 6C is a cross-sectional view taken along X-X' in Figure 6B, where the upper surface in Figure 6C represents the outer surface 11 of the release sheet FA and the lower surface in Figure 6C represents the inner surface 12 of the release sheet FA. The inner surface 12 of the release sheet FA has irregularities of a similar degree to those of the outer surface 11 of the release sheet FA. Figure 6D is a cross-sectional view of the adhesive layer A in which the irregularities of the inner surface 12 of the release sheet FA have been reversed and transferred, and the surface of the adhesive layer A reproduces the irregularities of the outer surface 11 of the release sheet FA. As shown in Figure 6B, if the protrusions are continuous on the outer surface 11 of the release sheet FA, independent recesses are formed in the adhesive layer A as shown in Figure 6D. On the other hand, as shown in Figure 6E, if the outer surface of the release sheet FA has a regular polka-dot pattern consisting of independent circular protrusions and continuous recesses, continuous recesses are formed on the surface of the adhesive layer A formed by the inverse transfer of the protrusions and recesses of the inner surface 12 of the release sheet FA, as shown in Figure 6G, and the recesses reach the edge of the adhesive layer A. From the viewpoint of ensuring airflow in the adhesive layer A, it is preferable that the protrusions on the outer surface 11 of the release sheet FA are independent and the recesses are continuous to the edge. The same applies to triangles and polygons in addition to polka-dot patterns. Furthermore, as shown in Figure 6H, examples can also be given of release sheets FA where identical or similar patterns overlap on the outer surface of the release sheet FA, with independent protrusions and continuous recesses. Also, as shown in Figure 6I, examples can be given of release sheets FA where continuous grid-like recesses and continuous recesses other than circular protrusions overlap.

[0036] Figure 7 shows an example where the surface 11 on the outside of the release sheet FA has no regularity in its irregular shape (plan view). The black areas represent convex parts and the white areas represent concave parts, and there is no regularity in the position of either of them, nor is there any regularity in their shape.

[0037] If the Beck smoothness of the outer surface of the release sheet FA on the adhesive sheet 1 for fixing the polishing pad with the release sheet FA is within the above range under conditions 1 and 2, there is no difference in terms of position adjustment when attaching to the surface plate or air release when the unevenness is attached, regardless of whether the shape of the unevenness in plan view is irregular and irregular or regular and regular. However, it is preferable that the pattern and design in plan view be regular and regular, as this makes it easier to find voids and unevenness when air enters that disrupts the regularity during attachment, and makes it easier to detect defects during the process using a CCD camera or similar device.

[0038] One method for obtaining an adhesive sheet 1 for fixing a polishing pad with a release sheet FA having a Beck smoothness within a predetermined range is to use a release sheet FA having irregularities on its surface with an average height Rc of 5 to 25 μm. Specifically, a pre-release sheet FA' having a release layer (not shown) is prepared, and then, as shown in Figure 8A, the pre-release sheet FA' is passed at high temperature between a metal roll R1 and a rubber roll R2 that have been processed to a desired surface shape, thereby inverting and transferring the surface shape of the metal roll R1 and producing a release sheet FA having irregularities with an average height Rc of 5 to 25 μm. Note that when the surface shape of the release sheet FA is inverted and transferred by the rotation of the metal roll R1, the surface shape will have a certain periodicity, but this periodicity is different from the regularity in the plan view described above. Incidentally, when measuring the Beck smoothness of an adhesive sheet 1 for fixing a polishing pad with a release sheet FA formed using such an irregular release sheet FA, the irregularities on the outer surface of the release sheet FA are deformed (crushed) by the pressure applied during measurement. The deformation of the unevenness on the outer surface of the release sheet FA is affected by the thickness and hardness of the adhesive layer A in contact with the inner surface of the release sheet FA. For example, if the adhesive layers are of the same type, the thicker they are, the easier it is for stress to be relieved, so the unevenness on the outer surface of the release sheet FA will be flattened more. For this reason, the Beck smoothness value of the adhesive sheet 1 for fixing the polishing pad with the release sheet FA will be larger. The Beck smoothness value of the adhesive sheet 1 for fixing the polishing pad with the release sheet FA is a value that takes into account the deformation of the unevenness on the outer surface of the release sheet FA and the deformation of the unevenness of the adhesive layer A in contact with the inner surface of the release sheet FA due to pressure. Therefore, the Beck smoothness value of the adhesive sheet 1 for fixing the polishing pad with the release sheet FA is related to the ease of application and air release when attaching the adhesive layer A to the surface plate SP, the adhesive strength and holding strength to the surface plate, and the polishing accuracy.

[0039] The pressure-sensitive adhesive sheet for polishing pad fixation with release sheet FA and release sheet FB of the present disclosure can be produced, for example, by the following method. (1) The pressure-sensitive adhesive a is applied onto the release layer of the release sheet FA, and dried as necessary to form the pressure-sensitive adhesive layer A. (2) A sheet-shaped base material is superposed on the surface of the pressure-sensitive adhesive layer A that is not in contact with the release sheet FA. (3) The pressure-sensitive adhesive b is applied onto the release-treated surface of the release sheet FB, and dried as necessary to form the pressure-sensitive adhesive layer B. (4) The surface of the pressure-sensitive adhesive layer B that is not in contact with the release sheet FB is superposed on the surface of the sheet-shaped base material that is not in contact with the pressure-sensitive adhesive layer A. As a result, the pressure-sensitive adhesive sheet 2 for polishing pad fixation with a release sheet having a laminated configuration of [release sheet FA / pressure-sensitive adhesive layer A / sheet-shaped base material F / pressure-sensitive adhesive layer B / release sheet FB] as shown in FIG. 8B can be produced.

[0040] Alternatively, the pressure-sensitive adhesive sheet for polishing pad fixation with a release sheet having a laminated configuration of [release sheet FA / pressure-sensitive adhesive layer A / sheet-shaped base material F / pressure-sensitive adhesive layer B / release sheet FB] as shown in FIG. 8B can also be produced by the following method. (5) The pressure-sensitive adhesive a is applied to one surface of the sheet-shaped base material F, and dried as necessary to form the pressure-sensitive adhesive layer A. (6) The surface of the release sheet FA, on which the average height Rc of the irregularities on the release-treated surface is 5 to 25 μm, is superposed on the surface of the pressure-sensitive adhesive layer A that is not in contact with the sheet-shaped base material F. (7) The pressure-sensitive adhesive b is applied onto the release-treated surface of the release sheet FB, and dried as necessary to form the pressure-sensitive adhesive layer B. (8) The surface of the pressure-sensitive adhesive layer B that is not in contact with the release sheet FB is superposed on the surface of the sheet-shaped base material F that is not in contact with the pressure-sensitive adhesive layer A.

[0041] Alternatively, an adhesive sheet for fixing a polishing pad with a release sheet, having a laminated structure of [release sheet FA / adhesive layer A / sheet-like substrate F / adhesive layer B / release sheet FB] as shown in Figure 8B, can also be manufactured by the following method: (9) Apply adhesive b to the peeled surface of release sheet FB and dry as necessary to form adhesive layer B. (10) Place the sheet-like substrate F on the surface of adhesive layer B that is not in contact with release sheet FB. (11) Apply adhesive a to the surface of release sheet FA, where the average height Rc of the surface irregularities of the peeled surface is 5 to 25 μm, and dry as necessary to form adhesive layer A. (12) Place the surface of adhesive layer A that is not in contact with release sheet FA on the surface of sheet-like substrate F that is not in contact with adhesive layer B. In either method, it is preferable that the surface of adhesive layer B (the surface that will be in contact with the polishing pad) does not have irregularities, so it is preferable that the peeled surface of release sheet FB to which adhesive b is applied is smooth.

[0042] For coating the adhesive, known methods such as the roll coater method, comma coater method, lip coater method, die coater method, reverse coater method, silkscreen method, and gravure coater method can be used. After coating, it can be dried using a hot air oven, infrared heater, or the like.

[0043] From the adhesive sheet for fixing the polishing pad, which has a laminated structure of [release sheet FA / adhesive layer A / sheet-like substrate F / adhesive layer B / release sheet FB] obtained by various methods, the release sheet FB is peeled off, and as shown in Figure 8C, the polishing pad PP is attached to the exposed adhesive layer B, thereby obtaining a polishing pad 3 with a laminated structure of [release sheet FA / adhesive layer A / sheet-like substrate F / adhesive layer B / polishing pad PP], which has a release sheet A and adhesive layer A attached. Next, from the obtained polishing pad 3 with release sheet FA and adhesive layer A, the release sheet FA that covered the adhesive layer A is peeled off, thereby obtaining a polishing pad 4 with adhesive layer A in which the unevenness of the inner surface of the release sheet FA is reversed and transferred. Then, as shown in Figure 8D, the polishing pad PP can be fixed to the surface plate SP via the adhesive sheet 5 by attaching the exposed adhesive layer A to the surface plate SP.

[0044] <Adhesive Layer> The adhesive layer A and the adhesive layer B in the adhesive sheet 5 for fixing a polishing pad of the present disclosure are respectively located on the respective outermost surfaces of the adhesive sheet 5. The sheet-like base material F may be a single layer, or may be a laminate of various members, and the number of laminated layers is not particularly limited. The thickness of the adhesive layer A of the adhesive sheet 5 for fixing a polishing pad is preferably 15 to 100 μm, more preferably 30 to 70 μm. By setting the thickness of the adhesive layer A to 15 μm or more, the adhesive force is easily exhibited. In addition, as the thickness increases, the unevenness of the adhesive layer A formed by using the release sheet FA is more likely to be crushed, and the air permeability when attached to the platen SP deteriorates. Therefore, when the thickness is 100 μm or less, the uneven shape required by the present disclosure is easily maintained even under applied pressure during the polishing process. By being in the more preferable range, the adhesiveness is excellent, and the problem that the adhesive layer shifts in the shear direction when the adhesive sheet reaches a high temperature during polishing is suppressed. The thickness is an average value obtained by measuring any 5 points with a 7.5 mm diameter probe at a pressing pressure of 0.01 N using a Lightmatic VL-50B thickness gauge manufactured by Mitutoyo Corporation. The thickness of the adhesive layer B is not particularly limited as long as various polishing pads can be fixed, but by setting the total thickness including the thickness of the adhesive layer A excluding the thickness of the base material layer to 200 μm or less, the proportion of the adhesive layer, which is a low-elasticity body in the entire adhesive sheet, is reduced, and the polishing accuracy is improved.

[0045] For the adhesive layers A and B of the adhesive sheet of the present disclosure, acrylic adhesives, elastomer adhesives, urethane adhesives, silicone adhesives and the like can be used, and two or more types may be used in combination. From the viewpoints of less gel generation, less likelihood of local difference in elastic modulus, and easy control of adhesive force, an acrylic adhesive layer using an acrylic adhesive is preferred. While metal catalysts are often used during the synthesis of elastomer adhesives and urethane adhesives, and metal catalysts are often used during curing for silicone adhesives, acrylic adhesives have a low metal catalyst content, so they are less likely to affect CMP processing and are also preferable from the viewpoint of high chemical resistance. In addition, for the adhesive layer B, it is preferable to select an acrylic adhesive with abundant monomer types in order to be compatible with a wide variety of polishing pad materials.

[0046] <Acrylic Adhesive> The acrylic adhesive contains an acrylic copolymer and a curing agent. It may also contain a tackifying resin. The acrylic copolymer preferably has carboxyl groups or hydroxyl groups, and more preferably is a (meth)acrylate resin having hydroxyl groups.

[0047] The (meth)acrylate resin is obtained by copolymerizing a monomer having a hydroxyl group with another monomer that does not have a hydroxyl group. That is, the (meth)acrylate resin is a copolymer consisting of units derived from a monomer having a hydroxyl group and units derived from another monomer.

[0048] Examples of monomers having a hydroxyl group include hydroxyalkyl (meth)acrylates and compounds obtained by adding ε-caprolactone to the hydroxyalkyl (meth)acrylate, with hydroxyalkyl (meth)acrylates being preferred.

[0049] Specific examples of hydroxyalkyl (meth)acrylates include hydroxyalkyl (meth)acrylates with 1 to 4 carbon atoms in the alkyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Specific examples of compounds obtained by adding ε-caprolactone to hydroxyalkyl (meth)acrylates include ε-caprolactone adducts of hydroxyalkyl (meth)acrylates with 1 to 4 carbon atoms, such as a 1-mol ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate, a 2-mol ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate, and a 3-mol ε-caprolactone adduct of 2-hydroxyethyl (meth)acrylate, but this disclosure is not limited to these examples. These hydroxyl group-containing monomers may be used individually or in combination. 2-hydroxyethyl (meth)acrylate is particularly preferred because, when crosslinked with an isocyanate curing agent, the intermolecular distances are relatively close, improving chemical resistance.

[0050] Other monomers that do not have a hydroxyl group include a variety of monomers such as those listed below. Examples of alkyl (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and tert-butylhexyl (meth)acrylate, as well as 2-acetoacetoxyethyl (meth)acrylate and phenoxyethyl (meth)acrylate.

[0051] The weight-average molecular weight (Mw) of the acrylic copolymer is preferably 200,000 to 1,800,000, and more preferably 500,000 to 1,500,000. A weight-average molecular weight (Mw) of 200,000 or more makes it easier for the adhesive to obtain cohesive force that can withstand strong shear forces, while a weight-average molecular weight (Mw) of 1,800,000 or less provides excellent heat resistance and prevents a decrease in adhesion to abrasive materials, thus improving performance.

[0052] Methods for polymerizing monomers include, for example, solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization, but this disclosure is not limited to such polymerization methods. Among these polymerization methods, solution polymerization is preferred because the resulting reaction mixture can be used as is.

[0053] <Elastomer-based adhesives> Elastomer-based adhesives contain an elastomer and a tackifying resin. The elastomer preferably contains a styrene-isoprene block copolymer.

[0054] Styrene isoprene block copolymers exist with either a linear or radial structure. However, the linear structure offers superior flexibility, resulting in excellent adhesion to various substrates and superior tackiness and heat resistance. Therefore, a linear structure consisting of a triblock (SIS) of styrene blocks and a diblock (SI) of styrene-isoprene is preferable. A linear styrene isoprene block copolymer refers to a linear copolymer in which styrene blocks and isoprene blocks are bonded together.

[0055] The styrene-isoprene block copolymer preferably has a styrene content of 20 to 40% by weight per 100% by weight. The diblock content is preferably 15 to 70% by weight. When the styrene content and diblock content are within the above ranges, it can have excellent adhesive properties with strong cohesive force, and its holding power and chemical resistance after being in a high-humidity environment are improved.

[0056] Examples of styrene-isoprene block copolymers include, but are not limited to, Kraton D1119 (manufactured by Kraton, styrene content 22% by weight, diblock content 66% by weight), Kraton D1126 (manufactured by Kraton, styrene content 21% by weight, diblock content 30% by weight), and Kraton D1117 (manufactured by Kraton, styrene content 17% by weight, diblock content 33% by weight). Two or more types may be used in combination as needed.

[0057] Furthermore, natural rubber may be included, as long as it does not impair the required performance. The natural rubber is not particularly limited, but it is preferable to knead it using a kneading roll and set the Mooney viscosity to, for example, 10 to 100. Other elastomers and natural rubbers are not limited to these and can be used individually or in combination of two or more.

[0058] <Silicone-based adhesives> Silicone-based adhesives can use materials known as silicone resins. Specifically, organopolysiloxanes having silanol groups at both ends of the molecular chain, with R in the molecule. ３ SiO ０．５(Here R represents a substituted or unsubstituted monovalent hydrocarbon group) Triorganosiloxane units represented by and SiO ２ Examples include those obtained by partial dehydration condensation of organopolysiloxanes having units. These are available as silicone adhesives KR-101-10, KR-120, KR-130, and X-40-3068 (all manufactured by Shin-Etsu Chemical Co., Ltd.). There are generally two curing methods for silicone adhesives: a curing method using peroxides such as benzoyl peroxide, and a curing method utilizing the reaction between a platinum catalyst and an organopolysiloxane having Si-H bonds. Both methods can be used, and they can also be used in combination.

[0059] <Tackifying Resins> Examples of tackifying resins include rosin-based resins such as rosin esters, polymerized rosin, hydrogenated rosin, disproportionated rosin, maleic acid-modified rosin, fumaric acid-modified rosin, and rosinphenol resins; terpene-based resins such as α-pinene resin, β-pinene resin, dipentene resin, aromatically modified terpene resin, hydrogenated terpene resin, terpenephenol resin, acid-modified terpene resin, and styrene-modified terpene resin; alkylphenol resins, coumarone-based resins, styrene-based resins, petroleum-based resins or their copolymers, with terpenephenol resins being particularly preferred. The above tackifying resins can be used individually or in combination of two or more.

[0060] <Hardening Agent> A hardening agent can be added to the adhesive as needed. The required peeling force when peeling from the polishing machine platen varies from high to low adhesive strength, so a hardening agent can be added to control the adhesive strength. As a hardening agent, isocyanate-based hardening agents, aziridine-based hardening agents, metal chelate-based hardening agents, and epoxy-based hardening agents can be used as needed, within a range that does not impair the desired performance. In particular, isocyanate-based hardening agents are preferred when added to acrylic adhesives from the viewpoint of cohesive strength and heat resistance. These hardening agents may be used individually or in combination of two or more types.

[0061] <Other Additives> Various adhesives for forming the adhesive layer in the adhesive sheet of this disclosure may include, as necessary, various additives such as antioxidants and other known anti-aging agents, fillers, pigments, dyes, diluents, plasticizers, polymerization inhibitors, UV absorbers, UV stabilizers, coupling agents, etc., and two or more types may be used in combination. Furthermore, the amount of additives added is not particularly limited, as long as it is an amount that obtains the necessary physical properties.

[0062] The adhesive layer A on the surface plate SP side should preferably achieve both alignment during adhesion and fixation during the polishing process, and should also exhibit little change in adhesive strength even after immersion in an alkaline aqueous solution. From this viewpoint, the adhesive strength of the adhesive layer A on the surface plate SP side before immersion is not particularly limited, but 5 to 25 N / 25 mm is preferred, and 15 to 20 N / 25 mm is particularly preferred. Furthermore, it is preferable that the change in adhesive strength after polishing is small. Specifically, it is preferable that the change in adhesive strength after immersion in a sodium hydroxide aqueous solution with a pH of 11.5 while attached to a stainless steel plate and left at 40°C for 24 hours is small. Generally, the adhesive strength after immersion in an alkaline aqueous solution tends to increase as the cohesive force decreases due to swelling of the adhesive layer, but this decrease in cohesive force can be suppressed by improving the crosslinking density with a hardening agent. However, increasing the crosslinking density reduces the adhesive strength before immersion, so it is a trade-off performance. Therefore, the balance between the two is important. Compared to a so-called sand-grain pattern, where the surface irregularities of the adhesive layer are irregular and shapeless, a grid pattern makes it easier to flatten the surface of the protrusions of the adhesive layer A that come into contact with the surface plate SP. For this reason, the contact area ratio with the object to be bonded is less likely to change due to external factors such as swelling and load immediately after bonding, and the polishing accuracy and polishing rate of the wafer do not change easily even when polishing wafers multiple times, which is preferable in that it improves the number of times the polishing pad can be used. After bonding, the polishing pad PP is less likely to shift, and considering the stability of the polishing process, the initial adhesive force is preferably 5 N / 25 mm or more, and less than 30 N / 25 mm in terms of repositioning (positioning) during bonding. 10 to 20 N / 25 mm is particularly preferred in terms of ease of positioning and resistance to shifting and peeling even when various stresses are applied during the polishing process. The adhesive strength in this disclosure refers to the value measured in accordance with the measurement method of JIS Z1528:2009, using a tensile testing machine under conditions of a peel angle of 180 degrees and a peel speed of 0.3 m / min at 23°C and a 50% RH atmosphere.

[0063] Adhesive layer A has a 0.5 cm adhesive layer that adheres tightly to the surface plate when bonded, in order to ensure air release and secure fixation to the surface plate. ２A contact area ratio of 60-90% is preferable, 62-80% is more preferable, and 65-75% is particularly preferable. A contact area ratio of 60% or more ensures that the adhesion does not change significantly immediately after fixing to the surface plate and during polishing. When the polishing target is changed and polishing is repeated without changing the polishing pad attached to the surface plate, variations in polishing volume between polishing lots are less likely. A ratio of 90% or less provides excellent air release and suppresses gaps during application. As will be described later, the contact area ratio is determined by applying a 2kg roller back and forth once after the adhesive layer A, exposed by peeling off the release sheet FA of the adhesive sheet, is bonded to the metal-deposited surface of the separator using a hand roller. Then, the surface of the separator is examined at different locations using a digital microscope (Keyence Corporation) with a coaxial light source at 20x magnification (field of view approximately 1.0 cm²). ２ Three images are taken using the same method. The result is the average of the three images, representing the percentage of areas where the vapor-deposited film is attached compared to areas where it is not.

[0064] <Release Sheet FA>, <Release Sheet FB> Release Sheet FA and Release Sheet FB have a release layer formed by coating a release agent onto a sheet-like substrate such as a plastic film or synthetic paper mainly made of plastic such as polypropylene. For CMP processing, a release sheet made of a highly clean plastic film as the sheet-like substrate is preferred. For the plastic film used for Release Sheet FA, polyethylene terephthalate film is preferred because it is easy to process with a metal roll and is inexpensive. Furthermore, compared to cutting or laser processing, processing with a metal roll is preferable because it is less prone to foreign matter contamination and results in a product with superior cleanliness. In addition, for the example processing with a metal roll, it is preferable to use a release sheet with a thickness of 25 to 100 μm, and more preferably 45 μm to 80 μm. This range makes it easy to transfer the desired shape formed on the metal surface to the release sheet (transferability), the outside and inside of the release sheet FA become the same shape but inverted (reversibility), and the pattern on the surface of the adhesive layer A formed by coating the inside of the release sheet FA becomes the shape of the inside of the release sheet FA. Through this series of processes, the uneven pattern of the metal roll can be reproduced with good reproducibility onto the surface of the adhesive layer A. In terms of inverting and transferring the unevenness on the inside of the release sheet FA to the surface of the adhesive layer A, the average height Rc on the outside of the release sheet FA is preferably 5 to 25 μm, more preferably 7 to 20 μm, and even more preferably 10 to 15 μm. Being within this preferred range allows the uneven state to be reproduced on the adhesive layer A with high accuracy.

[0065] For the release sheet FB, an inexpensive and highly smooth polyethylene terephthalate film is preferred as the plastic film. While there are no particular restrictions on the thickness of the release sheet FB, a thickness of 10 to 200 μm is preferred as it provides stiffness to the film and makes it easier to peel. Examples of release agents used in the release sheet FA and release sheet FB include silicone resins, alkyd resins, melamine resins, fluororesins, and acrylic resins. Among these, silicone resins are preferred.

[0066] <Sheet-like Substrate> The sheet-like substrate F of this disclosure is preferably a nonwoven fabric or a plastic film. Examples of plastic films include films made of polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, PPS (polyphenylene sulfide), nylon, triacetylcellulose, cycloolefin, polyimide, and polyamide. In particular, polyethylene terephthalate films are preferred because they are inexpensive to manufacture and have excellent chemical resistance and smoothness.

[0067] The thickness of the sheet-like substrate F is not particularly limited, but is preferably 5 to 200 μm, more preferably 25 to 75 μm, and particularly preferably 50 to 75 μm. Being within this preferred range prevents the unevenness of the adhesive layer A from affecting the adhesive layer B or the polishing pad, and provides appropriate stiffness, improving workability during application. Being within this particularly preferred range further improves workability.

[0068] The sheet-like substrate F in this disclosure may be subjected to an easy-adhesion treatment to improve the adhesion between adhesive layers A and B. The easy-adhesion treatment can be performed using known methods such as a dry method involving corona discharge and a wet method involving coating with an anchor coat agent. When an acrylic adhesive is used to form the adhesive layer, it is preferable to use one that has undergone the easy-adhesion treatment in terms of improving adhesion. On the other hand, in the case of an elastomer adhesive, if an easy-adhesion treatment by corona discharge is applied, the adhesive layer tends to peel off the sheet-like substrate more easily, so it is preferable to apply the elastomer adhesive to the surface that has not undergone the easy-adhesion treatment.

[0069] The thickness of the adhesive sheet 5 for fixing the polishing pad, which consists of an adhesive layer A, a sheet-like substrate F, and an adhesive layer B, is preferably 80 to 300 μm, and more preferably 100 to 200 μm. A thickness of 80 μm or more allows for uniform processing without uneven force distribution during lamination when integrating with the polishing pad PP, and a thickness of 300 μm or less allows for a roll shape to be used during the manufacturing of the adhesive sheet 5, increasing productivity. A thickness within the more preferable range ensures that the force from the surface plate SP is appropriately transmitted to the polishing pad PP during polishing, improving polishing accuracy.

[0070] <Usage Forms> An example of usage forms for the adhesive sheet for fixing polishing pads of this disclosure will be described. As shown in Figures 1B and 8B, the adhesive sheet for fixing polishing pads can be provided as a release sheet FA with each surface of the adhesive sheet for fixing polishing pads covered with release sheets FA and FB, respectively. Alternatively, as shown in Figure 1A, the adhesive sheet for fixing polishing pads can be provided with only the adhesive layer A side covered with the release sheet FA. In the form of Figure 1A, as shown in Figure 1E, the adhesive sheet 1 for fixing polishing pads with the release sheet FA is wrapped around a cylindrical member 6 called a core (also called a core material), and the surface of the adhesive layer B is covered with another surface of the release sheet FA (the surface not in contact with the adhesive layer A), thereby providing a roll-shaped adhesive sheet for fixing polishing pads with the release sheet FA.

[0071] As shown in Figures 1C and 8C, the polishing pad PP is laminated onto the surface of the adhesive layer B of the adhesive sheet for fixing the polishing pad with a release sheet FA, thereby forming the polishing pad 3 with the release sheet FA and adhesive layer A. Next, as shown in Figures 1D and 8D, the release sheet FA is peeled off to expose the adhesive layer A, and the polishing pad with adhesive layer A is attached to the surface plate SP. The adhesive layer A of the adhesive sheet for fixing the polishing pad is in contact with the surface plate SP, and the adhesive layer B is in contact with the polishing pad PP.

[0072] Polishing pads (PP), also known as polishing cloth, polishing pads, or polishing pads, are components that come into contact with the surface of the object to be polished and polish it. Polishing pads come in two types: single-layer types made from a single material and multi-layer types made by laminating multiple materials. The outermost surface material of polishing pads can be made from materials such as urethane, non-woven fabric, or suede. In the case of multi-layer types, urethane foam, polyethylene foam, or polypropylene foam are used as cushioning materials in the inner layers.

[0073] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples. In the examples, "parts" means "parts by weight" and "%" means "percent by weight".

[0074] [Molecular Weight] In the following examples, the molecular weight is the weight-average molecular weight in polystyrene equivalent, measured by GPC (gel permeation chromatography). The measurement was performed using GPC-8020 (manufactured by Tosoh Corporation) and tetrahydrofuran as the eluent. Three TSKgelSuperHM-M columns (manufactured by Tosoh Corporation) were used, and the measurement was performed at a column temperature of 40°C, a flow rate of 0.6 mL / min, a sample concentration of 0.3%, and an injection volume of 10 μL.

[0075] [Non-volatile content] Non-volatile content refers to the value obtained by dividing the mass of the sample after heating 1 g of the sample at 170°C for 10 minutes by the mass of the sample before heating. However, in the case of commercially available products, the value calculated according to the method specified by the manufacturer may be used.

[0076] (Adhesive) <Preparation of solution of acrylic adhesive (P-1)> 500 g of ethyl acetate was heated in a water bath in a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, while introducing nitrogen gas. Subsequently, a mixture of 360 g of BA (n-butyl acrylate), 120 g of 2-EHA (2-ethylhexyl acrylate), 10 g of AA (acrylic acid), 5 g of HEA (hydroxyethyl acrylate), and 0.5 g of AIBN (azobisisobutyronitrile) as an initiator was added dropwise to the ethyl acetate and reacted for 8 hours while maintaining reflux. After the reaction, 110 g of ethyl acetate was added to obtain a solution of (meth)acrylate resin p-1 with a weight-average molecular weight (Mw) of 510,000 (non-volatile content 45%). Furthermore, 100 parts of a solution of (meth)acrylate resin p-1 and 3 parts of an isocyanate-based curing agent (Mittec GP105A, manufactured by Mitsubishi Chemical Corporation: an adduct of tolylene diisocyanate and trimethylolpropane) were stirred and mixed, and methyl ethyl ketone was added as a solvent to prepare a solution of acrylic adhesive (P-1) (hereinafter also referred to as adhesive (P-1)) (non-volatile content 45%).

[0077] <Preparation of the acrylic adhesive (P-2) solution> In a four-necked flask equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer, 500 g of ethyl acetate was heated in a water bath while introducing nitrogen gas. Subsequently, a mixture of 120 g of BA (n-butyl acrylate), 360 g of 2-EHA (2-ethylhexyl acrylate), 20 g of AA (acrylic acid), and 0.3 g of AIBN (azobisisobutyronitrile) as an initiator was added dropwise to the ethyl acetate and reacted for 8 hours while maintaining reflux. After the reaction, 110 g of ethyl acetate was added to obtain a solution of (meth)acrylate resin p-2 with a weight-average molecular weight (Mw) of 800,000 (non-volatile content 45%). Furthermore, 100 parts of a solution of (meth)acrylate resin p-2 and 3 parts of an isocyanate-based curing agent (Mittec GP105A, manufactured by Mitsubishi Chemical Corporation: an adduct of tolylene diisocyanate and trimethylolpropane) were stirred and mixed, and methyl ethyl ketone was added as a solvent to produce a solution of acrylic adhesive (P-2) (hereinafter also referred to as adhesive (P-2)) (non-volatile content 45%).

[0078] <Preparation of acrylic adhesive (P-3) solution> 100 parts of (meth)acrylate resin p-2 solution (45% non-volatile content), 10 parts of O-130P (manufactured by Adeka, epoxidized soybean oil), and 3 parts of isocyanate curing agent (manufactured by Mitsubishi Chemical Corporation (Mytec GP105A): adduct of tolylene diisocyanate and trimethylolpropane) were stirred and mixed, and methyl ethyl ketone was added as a solvent to produce an acrylic adhesive (P-3) solution (45% non-volatile content).

[0079] <Preparation of Elastomer Adhesive (P-4) Solution> In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, 100 parts of Quintac 3270 (manufactured by Nippon Zeon Co., Ltd., styrene content 24% by weight, diblock content 67% by weight) as the elastomer and appropriate amounts of methyl ethyl ketone and toluene as solvents were charged under a nitrogen atmosphere. The flask was then gradually heated and continued heating at an internal temperature of approximately 50°C for 3 hours. After heating was completed, it was cooled to an internal temperature of approximately 40°C or lower. Under these conditions, 39 parts of YS Polystar T130 (manufactured by Yasuhara Chemical Co., Ltd., softening point 130±5℃, hydroxyl value 60 mg KOH / g) as a tackifying resin, 10 parts of O-130P (manufactured by Adeka Co., Ltd., epoxidized soybean oil), and 2 parts of Irganox 1010 (manufactured by BASF Japan, antioxidant) were charged and diluted with methyl ethyl ketone and toluene. Stirring was continued until the tackifying resin dissolved, and 1 part of an isocyanate-based curing agent (Mittec GP105A, manufactured by Mitsubishi Chemical Corporation: adduct of tolylene diisocyanate and trimethylolpropane) was added to obtain a solution of elastomer adhesive (P-4) (hereinafter also referred to as adhesive (P-4)) (non-volatile content 40%).

[0080] As a pre-release sheet for the release sheet <FA-1>, a PET release sheet "RF2PETCS001-50" manufactured by I'm Co., Ltd., measuring approximately 30 cm x 30 cm (thickness: 50 μm, one side silicone release treatment, Rc: 0.2 μm), is prepared. A grid pattern as shown in Figure 6A (area of ​​the grid surface, which is a recess in the mold: 2.4 mm) is used. ２ A release sheet FA-1 with the grid pattern transferred onto it was obtained by passing the pre-release sheet between a metal roll with a mold protrusion (width of the mold protrusion: 200 μm, height of the mold protrusion: 8 μm) and a rubber roll under the conditions of temperature: 220°C, pressure: 5 MPa, and speed: 3 m / min. The outer Rc of the release sheet <FA-1> measured by the above method using a laser microscope (Keyence VK-X100) was 5.2 μm. The thickness of the PET release sheet was the average value of measurements taken at 5 arbitrary points using a thickness gauge Lightmatic VL-50B (Mitutoyo Corporation) with a Φ7.5 mm probe and a pressing pressure of 0.01 N.

[0081] Manufacturing of release sheets <FA-2> to <FA-5> Release sheets FA-2 to FA-5 were obtained under the same processing conditions as for release sheet FA-1, except that the recesses of the metal roll used in the manufacture of release sheet FA-1 were further cut to raise the protrusions.

[0082] Manufacturing of release sheet <FA-6> Instead of the metal roll used in the manufacturing of release sheet FA-1, a pattern with a grid and diagonal protrusions as shown in Figure 5A (triangular area of ​​mold recess: 0.9 mm) is used. ２ A release sheet FA-6 with the grid pattern transferred onto it was obtained by passing it between a metal roll with mold protrusions (width of mold protrusions: 200 μm, height of mold protrusions: 6 μm) and a rubber roll under the conditions of temperature: 220°C, pressure: 5 MPa, and speed: 3 m / min.

[0083] Manufacturing of release sheets <FA-7> to <FA-10> Release sheets FA-7 to FA-10 were obtained under the same processing conditions as for release sheet FA-6, except that the recesses of the metal roll used in the manufacture of release sheet FA-6 were further cut to raise the protrusions.

[0084] The outer Rc of each release sheet FA-1 to FA-10 described in detail is as follows: ・FA-1: Transfer of grid pattern. Rc: 5.2 μm ・FA-2: Transfer of grid pattern mold with raised protrusions used in FA-1. Rc: 7.5 μm ・FA-3: Transfer of grid pattern mold with raised protrusions used in FA-1. Rc: 11.1 μm ・FA-4: Transfer of grid pattern mold with raised protrusions used in FA-1. Rc: 14.8 μm ・FA-5: Transfer of grid pattern mold with raised protrusions used in FA-1. Rc: 18.7 μm ・FA-6: Transfer of grid pattern and diagonal pattern. Rc: 5.4 μm FA-7: Transferred by raising the protrusions of the mold used for the grid pattern and diagonal pattern in FA-6. Rc: 11.5 μm FA-8: Transferred by raising the protrusions of the mold used for the grid pattern and diagonal pattern in FA-6. Rc: 14.5 μm FA-9: Transferred by raising the protrusions of the mold used for the grid pattern and diagonal pattern in FA-6. Rc: 18.1 μm FA-10: Transferred by raising the protrusions of the mold used for the grid pattern and diagonal pattern in FA-6. Rc: 23.6 μm

[0085] <Release Sheet FB> · FB-1: RF2PETCS001-50, manufactured by Im Co., Ltd., PET release sheet (thickness: 50 μm, single-sided silicone release treatment, Rc: 0.2 μm)

[0086] <Other Release Sheets> · FH-21: A mat-grade polyester film (manufactured by Unitika Ltd., Emblet "PTH-38"), on the gloss surface opposite to the mat surface of which, BYK's silicone treatment agent "BYK300" was applied with a coil bar at 0.1 g / m ２ and used as a release surface. Rc: 0.1 μm · FH-22: A mat-grade polyester film (manufactured by Unitika Ltd., Emblet "PTH-38"), on the mat surface opposite to the gloss surface of which, BYK's silicone treatment agent "BYK300" was applied with a coil bar at 0.1 g / m ２ and used as a release surface. Rc: 1.5 μm · FH-23: Release sheet FH-23 was obtained in the same manner as in the production of FA-1, except that the temperature when passing the pre-release sheet between the metal roll and the rubber roll was set to 175°C. Rc: 3.2 μm · FH-24: Transfer was performed by raising the protrusions of the lattice-patterned mold used in FA-1. Rc: 43.2 μm

[0087] <Sheet-shaped Base Material F> · Sheet-shaped base material F-1: PET25, PET film manufactured by Unitika Ltd. (thickness: 25 μm) · Sheet-shaped base material F-2: PET75, PET film manufactured by Unitika Ltd. (thickness: 75 μm) · Sheet-shaped base material F-3: PET5, PET film manufactured by Unitika Ltd. (thickness: 5 μm)

[0088] <Example 1> Manufacturing of an adhesive sheet for fixing a polishing pad and an adhesive sheet for fixing a polishing pad with a release sheet A solution of adhesive P-1 was applied to the release surface (inner surface) of release sheet FA-1 with a doctor blade to a thickness of 50 μm after drying, and dried in an oven at 80°C to form an adhesive layer A-1. A sheet-like substrate F-1 was then attached to the surface of adhesive layer A-1 with a hand roller. Separately, a solution of adhesive P-2 was applied to the release surface of release sheet FB-1 with a doctor blade to a thickness of 50 μm after drying, and dried in an oven at 80°C to form an adhesive layer B-1. Next, the side of adhesive layer B-1 opposite to the release sheet FB-1 was bonded to the side of adhesive layer A-1 opposite to the side of adhesive layer A-1 via the sheet-like substrate F-1 using a hand roller, thereby obtaining an adhesive sheet for fixing polishing pads with a laminated structure of [adhesive layer A-1 / sheet-like substrate F-1 / adhesive layer B-1], in which the release sheet FA-1 was attached to adhesive layer A-1 and the release sheet FB-1 was attached to adhesive layer B-1. The properties of the obtained adhesive sheet (Beck smoothness of the outer surface of release sheet FA, average height Rc, and difference in cutting level Rδc of the contour curve) were determined according to the method described later. Furthermore, the performance of the obtained adhesive sheet (workability for application, air release properties, adhesive strength, alkali resistance, holding power, and polishing accuracy) was evaluated according to the method described later.

[0089] <Examples 2-10> Except that the release sheets FA-2 to FA-10 were used instead of the release sheet FA-1, to which the adhesive P-1 solution was applied, as shown in Table 1, an adhesive sheet for fixing a polishing pad with a release sheet was obtained in the same manner as in Example 1.

[0090] <Examples 11-15> Except for using release sheet FA-3 or FA-4 instead of release sheet FA-1, and using the solution of adhesive P-4 instead of the solution of adhesive P-1 as shown in Table 1, as well as changing the thickness of adhesive layer A, changing the sheet-like substrate, and changing the type and thickness of adhesive layer B, adhesive sheets for fixing polishing pads with release sheets were obtained in the same manner as in Example 1.

[0091] <Comparative Examples 1-4> Except that the release sheets to which the adhesive P-1 solution is applied were replaced with FH-21 to FH-24 as shown in Table 1, the same procedure as in Example 1 was used to obtain adhesive sheets for fixing polishing pads with release sheets.

[0092] [Properties of the Adhesive Sheet] <Beck Smoothness> In the examples and comparative examples, the release sheet FB covering the adhesive layer B was peeled off from the adhesive sheet for fixing the polishing pad with a release sheet, and the exposed adhesive layer B was bonded to a 100 μm PET film (Rc: 0.2 μm) and cut to a size of 50 mm square. Next, two samples were stacked and a hole was formed in the center by cutting out a circle with a radius of 5 mm using a Thomson die, and this was made into a sample for measurement. The sample for measurement was placed on the glass plate of the Beck smoothness meter (manufactured by Kumagai Riki Kogyo Co., Ltd.) so that the outer surface of the release sheet FA of the sample for measurement was in contact with the glass plate and the hole in the sample for measurement was positioned directly above the central circular hole on the glass plate. A rubber press plate was placed on the upper surface of the PET film at the top of the sample for measurement, and with a pressure of 0.1 MPa applied through a pressure plate, suction was applied from below the circular hole in the center of the glass member, reducing the pressure to -50.7 kPa. Once the pressure reached -50.7 kPa, the depressurization was stopped. Condition 1: The time it took for the pressure to change from -50.7 kPa to -48.0 kPa, and Condition 2: The time it took for the pressure to change from -50.7 kPa to -29.3 kPa were measured five times each. The average value was calculated and then divided by 2, the number of layers stacked. If any of the five measurements exceeded 1000 seconds, the measurement was stopped and ">1000" was recorded in the table. Also, if any of the five measurements had a low smoothness and a measurement time of less than 0.1 seconds, or if the air inflow was too high and the vacuum level did not rise to -50.7 kPa, "0" was recorded in the table.

[0093] <Rc, Rδc> A vapor-deposited film with a thickness of approximately 20 nm was formed on the surface of the sheet to be measured using Vacuum Devices Co., Ltd.'s "MSP15" under the conditions of target: Pt-Pd, operating time: 1 minute, so that the laser from a laser microscope (Keyence VK-X100) was reflected off the outermost surface of the sheet. Measurements were taken using a laser microscope in accordance with JIS B 0601 (2013).

[0094] [Evaluation of Adhesive Sheets] <Ease of Application (Position Adjustment)> The procedure will be explained in accordance with Figure 9. As shown in Figure 9(a), the adhesive sheets for fixing polishing pads with release sheets prepared in the examples and comparative examples were cut to a size of 210 mm square, the release sheet FB was peeled off to expose the adhesive layer B, and it was bonded to a smooth glass plate G1 (approximately 300 g) with a thickness of 3 mm and a size of 200 mm square at 23°C and 50% RH. The adhesive sheet 5 that protruded from the four sides of the glass plate G1 was removed with a cutter to obtain a sample (hereinafter referred to as "sample") 21 for evaluating the ease of application, with the configuration of [glass plate G1 / adhesive sheet 5 / release sheet FA], which was 200 mm square. Note that in Figure 9, the laminated state of the adhesive sheets and the laminated state of the adhesive sheets and release sheet FA are not shown. As shown in Figure 9(b), two types of frame lines, 200 mm square and 150 mm square, are drawn on one side of the adherend G2, a 300 mm square glass plate, approximately in the center, using a 1 mm thick oil-based marker to create the evaluation adherend (hereinafter referred to as the adherend). As shown in Figure 9(c), the release sheet FA of the sample 21 is peeled off to expose the adhesive layer A, and the 200 mm square sample is placed on the adherend so that at least 10 mm of each side extends beyond two sides of the 200 mm square outer frame drawn on the adherend. The side on which the sample is placed is the side opposite to the side on which the two types of frames are drawn. Immediately after placement, the sample is peeled off the adherend G2, and as shown in Figure 9(d), the position is adjusted to match the 200 mm square frame of the adherend, and the time until reattachment (placement - peeling - reattachment) is measured. Five randomly selected individuals performed the task, each scoring as follows. The total score of the five individuals was then used to evaluate the ease of application. The scores for ease of application were as follows: 3 points: Aligned easily with the border within 10 seconds. 2 points: Aligned in between 10 and 15 seconds. 1 point: Aligned in between 15 and 30 seconds. 0 points: Exceeded 30 seconds. The evaluation criteria for ease of application were as follows: S: 13-15 points A: 10-12 points B: 7-9 points C: 4-6 points D: 0-3 points

[0095] <Evaluation of Air Release Performance> As shown in Figure 10(a), immediately after the evaluation of the bonding workability, a 500g balance weight 22 with a diameter of 41mm and a height of 63mm was placed in the center of the five evaluation samples 21 and left undisturbed for 180 seconds. Next, as shown in Figure 10(b), after removing the weight 22, points were assigned based on the number of air pockets with a diameter of 5mm or more inside the 150mm square frame line from the adherend G2 side (back side of the 300mm square glass plate), and the presence or absence of air pockets with a diameter of 10mm or more. Furthermore, the air release performance was evaluated from the total score of the five samples. The scoring criteria for air release performance were as follows: 3 points: 0 air pockets with a diameter of 5mm or more inside the frame. 2 points: 1 to 2 air pockets with a diameter of 5mm or more inside the frame, and no air pockets with a diameter of 10mm or more. 1 point: 3 to 5 air pockets with a diameter of 5mm or more inside the frame, and no air pockets with a diameter of 10mm or more. 0 points: There are more than 5 air pockets with a diameter of 5 mm or more within the frame, and there is an air pocket of 10 mm or more. The evaluation criteria for air release performance are as follows: S: 13-15 points A: 10-12 points B: 7-9 points C: 4-6 points D: 0-3 points

[0096] [Preparation of adhesive samples for measuring adhesive performance] <Evaluation of initial adhesive strength of adhesive layer A> Under a 23°C, 50% RH atmosphere, the release sheet FB was peeled off from the adhesive sheet used to fix the polishing pad with a release sheet, and the exposed adhesive layer B was bonded to a 25 μm PET film. The sample was then cut to a size of 25 mm wide x 100 mm long to be used for evaluating adhesive strength. Subsequently, the release sheet FA was peeled off, and the exposed adhesive layer A was placed on a stainless steel plate and pressed down with a 2 kg roller for one back-and-forth motion to adhere the adhesive layer A to the stainless steel plate. This was left for 24 hours. After that, the adhesive strength of adhesive layer A (adhesion strength to SUS) was measured in accordance with the measurement method of JIS Z1528:2009, under conditions of 23°C, 50% RH atmosphere, using a tensile testing machine with a peeling angle of 180 degrees and a peeling speed of 0.3 m / min. The obtained measured values ​​are shown in Table 1.

[0097] <Evaluation of Chemical Resistance> The release sheet FA was peeled off the sample used for adhesion strength evaluation, and the exposed adhesive layer A was placed on a stainless steel plate. A 2 kg roller was passed back and forth once to press the adhesive layer A to the stainless steel plate. Then, within 30 minutes, the sample was immersed in a sodium hydroxide aqueous solution with a pH of 11.5 while still attached to the stainless steel plate, and left at 60°C for 12 hours. After that, the sample was removed from the sodium hydroxide aqueous solution, washed with water, and left at 23°C and 50% RH for 1 hour. The adhesive strength was measured using the same method as in <Measurement of Initial Adhesion Strength> above and recorded as <Adhesion Strength After Immersion>, and the difference between the initial adhesive strength and the adhesive strength after immersion was calculated. The smaller this difference, the better the chemical resistance. The evaluation criteria for chemical resistance are as follows. S: Difference in adhesive strength is less than 1.0 N / 25 mm A: Difference in adhesive strength is 1.0 N / 25 mm or more, and less than 1.5 N / 25 mm B: Difference in adhesive strength is 1.5 N / 25 mm or more, and less than 2.0 N / 25 mm C: Difference in adhesive strength is 2.0 N / 25 mm or more, and less than 3.0 N / 25 mm D: Difference in adhesive strength is 3.0 N / 25 mm or more In CMP processing, which uses various chemicals depending on the material to be polished, strong chemical resistance is required. S is the best, A is preferred, B is used for general purposes, C has limited applications, and D cannot be used.

[0098] <Evaluation of Holding Force> The release sheet FA was peeled off the sample used for adhesive strength evaluation, and only a 25 mm wide x 25 mm long area of ​​the exposed adhesive layer A was placed on the stainless steel plate. A 2 kg roller was passed back and forth once to press the adhesive layer A to the stainless steel plate. After that, it was left for 20 minutes in an atmosphere of 23°C and 50% RH. Then, in an atmosphere of 80°C, a 1 kg weight was attached to the end of the sample that was not attached to the stainless steel plate and set so that a force was applied in the direction of 180 degrees, and the amount of displacement of the attached position in mm was measured after 24 hours. In addition, if the sample completely detached from the substrate, the time until it fell was measured. The evaluation criteria for holding force are as follows. S: Displacement less than 0.1 mm A: 0.1 mm or more, less than 1.0 mm B: Displacement 1.0 mm or more, 5.0 mm or less C: Falls after 180 min or more D: Falls after less than 180 min The smaller the displacement, the less likely slippage and peeling are to occur during polishing, and the stronger the polishing pad can be fixed, making it suitable for use in various polishing processes. S is the best, A is suitable for general use, B is suitable for general use, C has limited applications, and D cannot be used.

[0099] <Contact Area Ratio of Adhesive Layer A> Pt-Pd was deposited onto the peeling surface of a 4cm square piece of release sheet FB using a vacuum deposition apparatus (JEOL Ltd.) to form a deposited film. The release sheet FA was peeled off a 3cm square piece of adhesive sheet to expose adhesive layer A. Adhesive layer A and the deposited film of the 4cm square piece of release sheet FB were bonded together with a hand roller, and then a 2kg roller was passed back and forth once to prepare the sample for measurement. The state of the interface between adhesive layer A and the 4cm square piece of release sheet FB was examined using a digital microscope (KEYENCE Corporation) with a coaxial light source at 20x magnification (field of view approximately 1.0cm²) through the 4cm square piece of release sheet FB. ２ Observe the area using a microscope and take three photographs. For each of the three images, use image processing software (GIMP) to convert it to monochrome and then to binarization. Calculate the area ratio of the areas where the vapor-deposited film and adhesive layer A are in close contact with each other (represented by black in the image) and the areas where they are not in contact. The arithmetic mean of these ratios is then calculated and defined as the contact area ratio (%).

[0100] <Evaluation of Lot Differences in Polishing> The release sheet FB was peeled off from the adhesive sheet used to fix the polishing pad with a release sheet, and the non-polishing surface of the polishing pad (CMP cloth, Φ200 mm, normal type, manufactured by Musashino Electronics Co., Ltd.) was placed on the exposed adhesive layer B and bonded together under the conditions of roll temperature: 80°C, pressure: 0.1 MPa, and speed: 1.0 M / min to produce a polishing pad with an adhesive sheet. A Musashino Electronics Co., Ltd. MA-200 was used as the polishing machine, and the release sheet FA was peeled off from the prepared polishing pad with an adhesive sheet, and the exposed adhesive layer A was attached to an aluminum surface plate, and polishing was performed under the following conditions. (Conditions) Table rotation speed: 100 rpm Head rotation speed: 105 rpm Object to be polished: 200 mm wafer (thickness 75 μm) with a polysilicon layer (500 nm) deposited on its surface, cut into 3 cm square test pieces Polishing pressure: 10.0 kPa Polishing time: 15 min Polishing solution: Colloidal silica polishing compound #80 manufactured by Musashino Electronics After polishing, the test pieces were washed with water, air was blown onto the surface to remove water droplets, and the thickness of one point in the center of the test piece was measured using a film thickness gauge FE-300 manufactured by Otsuka Electronics. The polishing pad was not changed, but only the object to be polished was changed 10 times and polished under the same conditions, and the thickness of the 10 polished test pieces was measured, and the difference between the maximum film thickness and the minimum film thickness was determined and evaluated according to the following criteria. S: Less than 40 nm A: 40 nm or more, less than 60 nm B: 60 nm or more, less than 80 nm C: 80 nm or more, less than 100 nm For repeated use of polishing pads in CMP polishing where accuracy is required, S is the best, A is preferred, B is used for general purposes, and C cannot be used.

[0101]

[0102] This disclosure also discloses methods for manufacturing adhesive sheets for fixing polishing pads as described in

[13] to

[15] below.

[13] A method for manufacturing an adhesive sheet for fixing a polishing pad, comprising a release sheet FA, an adhesive layer A, a sheet-like substrate, an adhesive layer B, and a release sheet FB, comprising the following steps (1) to (4): (1) A step of applying adhesive a to the surface of a release sheet FA, wherein the shape of the recesses on the surface in plan view is regular and fixed, and the average height Rc of the unevenness of the peeled surface is 5 to 25 μm, thereby forming an adhesive layer A. (2) A step of overlapping the sheet-like substrate onto the surface of the adhesive layer A that is not in contact with the release sheet FA. (3) A step of applying adhesive b to the peeled surface of the release sheet FB, thereby forming an adhesive layer B. (4) A step of overlapping the surface of the adhesive layer B that is not in contact with the release sheet FB onto the surface of the sheet-like substrate that is not in contact with the adhesive layer A. A method for manufacturing an adhesive sheet for fixing a polishing pad with release sheet FA and release sheet FB, wherein the surface of the adhesive layer A that is not in contact with the sheet-like substrate has irregularities, and in a Beck smoothness test, the smoothness of the surface determined under condition 1 below is 0.1 to 30 seconds, and the smoothness of the surface determined under condition 2 below is 1 to 500 seconds. Condition 1: Time until the pressure changes from -50.7 kPa to -48.0 kPa. Condition 2: Time until the pressure changes from -50.7 kPa to -29.3 kPa.

[0103]

[14] : A method for manufacturing an adhesive sheet for fixing an abrasive pad, comprising a release sheet FA, an adhesive layer A, a sheet-like substrate, an adhesive layer B, and a release sheet FB, comprising the following steps (5) to (8): (5) A step of applying adhesive a to one side of a sheet-like substrate to form an adhesive layer A. (6) A step of overlapping the surface of a release sheet FA, in which the shape of the recesses on the surface is regular and fixed in plan view and the average height Rc of the unevenness of the peeled surface is 5 to 25 μm, onto the surface of the adhesive layer A that is not in contact with the sheet-like substrate. (7) A step of applying adhesive b to the peeled surface of a release sheet FB to form an adhesive layer B. (8) A step of overlapping the surface of the adhesive layer B that is not in contact with the release sheet FB onto the surface of the sheet-like substrate that is not in contact with the adhesive layer A. A method for manufacturing an adhesive sheet for fixing a polishing pad with release sheet FA and release sheet FB, wherein the surface of the adhesive layer A that is not in contact with the sheet-like substrate has irregularities, and in a Beck smoothness test, the smoothness of the surface determined under condition 1 below is 0.1 to 30 seconds, and the smoothness of the surface determined under condition 2 below is 1 to 500 seconds. Condition 1: Time until the pressure changes from -50.7 kPa to -48.0 kPa. Condition 2: Time until the pressure changes from -50.7 kPa to -29.3 kPa.

[0104]

[15] : A method for manufacturing an adhesive sheet for fixing an abrasive pad, comprising a release sheet FA, an adhesive layer A, a sheet-like substrate, an adhesive layer B, and a release sheet FB, comprising the following steps (9) to (12): (9) A step of applying adhesive b to the peeled surface of the release sheet FB to form the adhesive layer B. (10) A step of overlapping the sheet-like substrate onto the surface of the adhesive layer B that is not in contact with the release sheet FB. (11) A step of applying adhesive a to the surface of the release sheet FA, wherein the shape of the recesses on the surface in plan view is regular and fixed, and the average height Rc of the unevenness of the peeled surface is 5 to 25 μm, to form the adhesive layer A. (12) A step of overlapping the surface of the adhesive layer A that is not in contact with the release sheet FA onto the surface of the sheet-like substrate that is not in contact with the adhesive layer B. A method for manufacturing an adhesive sheet for fixing a polishing pad with release sheet FA and release sheet FB, wherein the surface of the adhesive layer A that is not in contact with the sheet-like substrate has irregularities, and in a Beck smoothness test, the smoothness of the surface determined under condition 1 below is 0.1 to 30 seconds, and the smoothness of the surface determined under condition 2 below is 1 to 500 seconds. Condition 1: Time until the pressure changes from -50.7 kPa to -48.0 kPa. Condition 2: Time until the pressure changes from -50.7 kPa to -29.3 kPa.

[0105] This application claims priority based on Japanese Patent Application No. 2025-067225, filed on 16 April 2025, and incorporates all of its disclosures herein.

[0106] 1: Adhesive sheet for fixing polishing pad with release sheet FA 2: Adhesive sheet for fixing polishing pad with release sheet FA and release sheet FB 3: Polishing pad with release sheet FA 4: Polishing pad with adhesive sheet for fixing polishing pad 5: Adhesive sheet for fixing polishing pad A: Adhesive layer A FA: Release sheet covering the surface of adhesive layer A FA': Pre-release sheet B: Adhesive layer B FB: Release sheet covering the surface of adhesive layer B F: Sheet-like substrate PP: Polishing pad R1: Metal roll R2: Rubber roll SP: Surface plate E: Rubber press plate G: Glass component H: Pressure plate PET: PET film

Claims

1. An adhesive sheet for fixing a polishing pad with a release sheet FA, comprising an adhesive layer A on one side of a sheet-like substrate and an adhesive layer B on the other side of the sheet-like substrate, wherein the surface of adhesive layer A not in contact with the sheet-like substrate is in contact with a release sheet FA, characterized in that the shape of the convex portions on the outer surface of the release sheet FA in plan view is regular and fixed, the average height Rc of the irregularities on the outer surface of the release sheet FA is 5 to 25 μm, and the outer and inner sides of the release sheet FA are identical in shape when reversed, the material of the release sheet FA is plastic, the outer surface of the release sheet FA not in contact with adhesive layer A has irregularities, and in a Beck smoothness test, the smoothness of the outer surface of the release sheet FA as determined by condition 1 below is 0.1 to 30 seconds, and the smoothness of the outer surface of the release sheet FA as determined by condition 2 below is 1 to 500 seconds. Condition 1: Time taken for the pressure to change from -50.7 kPa to -48.0 kPa. Condition 2: Time taken for the pressure to change from -50.7 kPa to -29.3 kPa.

2. The adhesive sheet for fixing a polishing pad with the release sheet FA according to claim 1, characterized in that the thickness of the release sheet FA is 25 to 100 μm.

3. The adhesive sheet for fixing a polishing pad with a release sheet FA according to claim 1, characterized in that the average height Rc of the surface irregularities on the outer surface of the release sheet FA is 5 to 25 μm, and the average height Rc of the surface irregularities on the inner surface of the release sheet FA is 5 to 25 μm.

4. The adhesive sheet for fixing a polishing pad with a release sheet FA according to claim 1, characterized in that the difference in cutting levels Rδc of the contour curve of the unevenness on the outer surface of the release sheet FA is 1 to 10 μm.

5. The adhesive sheet for fixing a polishing pad with a release sheet FA according to claim 1, characterized in that the adhesive layer A is an acrylic adhesive layer.

6. An adhesive sheet for fixing a polishing pad with a release sheet FA according to any one of claims 1 to 3, wherein the sheet is wound in a roll shape and the length in the width direction of the wound body is 1000 mm or less.

7. An adhesive sheet for fixing a polishing pad with a release sheet FA and a release sheet FB, comprising an adhesive sheet for fixing a polishing pad with a release sheet FA as described in any one of claims 1 to 3, wherein the release sheet FB is in contact with the surface of the adhesive layer B that is not in contact with the sheet-like substrate, and the material of the release sheet FB is plastic.

8. An adhesive sheet for fixing a polishing pad, comprising a release sheet FA and a release sheet FB according to claim 7, which is wound in a roll shape and has a length in the width direction of the wound body of 1000 mm or less.

9. An adhesive sheet for fixing a polishing pad with release sheet FA and release sheet FB according to claim 7, wherein the length of the shorter side is 1000 mm or less.

10. An adhesive polishing pad comprising a polishing pad and an adhesive sheet for fixing the polishing pad with a release sheet FA as described in any one of claims 1 to 5, wherein the polishing pad and the adhesive layer B are in contact with each other, the polishing pad with a release sheet FA and adhesive layer A.

11. A method for fixing a polishing pad to a surface plate via an adhesive sheet, characterized by peeling off the release sheet FA from the polishing pad with the release sheet FA and adhesive layer A as described in claim 10, and attaching the adhesive layer A to the surface plate.

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