Polishing pad, polishing tool, polishing apparatus, and polishing method

Abstract

The present disclosure relates to polishing pads, polishing tools, polishing apparatuses, and polishing methods. A polishing pad includes a base member including a first major surface and a second major surface opposite the first major surface. The base member is plate-like and deformable. A polishing surface is disposed on the first major surface. A plurality of lines are disposed in the base member along the first major surface.

Description

Technical Field

[0001] This disclosure relates to polishing pads and the like for polishing the surfaces of semiconductor substrates, optical lenses, etc. Background Technology

[0002] For example, in the polishing process of finishing semiconductor substrates or optical lenses, the surfaces of the semiconductor substrates or optical lenses are polished using polishing pads. During polishing, it is necessary to uniformly finish the entire polished surface of the object to reduce inhomogeneities in object thickness and variations in surface roughness. The dimensions of the individual semiconductor substrates and optical lenses being polished range from a few millimeters to several meters. If the workpiece to be polished is large, it may warp, resulting in partial contact where only a portion of the polishing pad contacts the workpiece. In such cases, it may be difficult to uniformly finish the workpiece. Therefore, it is desirable to increase the polishing pad's conformability to the workpiece shape and reduce partial contact to uniformly finish the workpiece.

[0003] Japanese Patent Application Publication No. H11-58199 describes a polishing method in which the support surface of a polishing pad is supported by an elastic member. In this method, since the elastic member deforms according to the warping of the workpiece, it is intended to increase the polishing pad's conformability to the workpiece shape with a relatively simple construction.

[0004] Japanese Patent Application Publication No. 2004-358591 describes another method for increasing the conformability of a polishing pad to the shape of a workpiece. In this method, the polishing pad polishes the workpiece while its supporting surface is supported by a fluid. Specifically, a space is formed between the polishing pad and a frame holding the outer periphery of the pad, and this space is filled with fluid. The polishing pad expands due to the pressure of the fluid, and in this state, the workpiece is polished by the polishing pad by pressing it against the polishing surface of the polishing pad. In this method, since the polishing pad can be supported by the fluid with a uniform pressure distribution, its conformability can be expected to be greatly improved compared to polishing in a configuration where the polishing pad is supported by an elastic member.

[0005] Therefore, it can be expected that the method of supporting the polishing pad with a fluid as described in Japanese Patent Application Publication No. H11-58199, which uses an elastic member to support the polishing pad, will improve the polishing pad's ability to follow the shape of the workpiece.

[0006] However, in polishing methods where the polishing pad is fluid-supported, if the polishing pad is used continuously for a long time, it may deform (or stretch) due to creep deformation, leading to a deterioration in follow-through. Specifically, in the method described in Japanese Patent Application Publication No. 2004-358591, the polishing pad expands due to fluid pressure, thus being continuously pulled in the longitudinal direction due to tension. Note that the longitudinal direction of the polishing pad described above is orthogonal to the thickness direction of the polishing pad and parallel to its surface. If the polishing pad is continuously pulled under tension, it will gradually and irreversibly stretch in the longitudinal direction over time due to creep deformation. If the polishing pad stretches in the longitudinal direction, it will warp during polishing, and the polishing surface of the pad will not make uniform contact with the workpiece. As a result, the polishing accuracy will deteriorate. Therefore, in conventional methods where the polishing pad is fluid-supported, it is impossible to maintain high follow-through for a long time.

[0007] One of the problems addressed by the embodiments disclosed in this specification and accompanying drawings is to provide a technique that can stably maintain the conformity of the polished surface of the polishing pad to the shape of the workpiece over a long period of time. However, the problems addressed by the embodiments disclosed in this specification and accompanying drawings are not limited to those described above. Problems corresponding to the effects of the various components shown in the following embodiments can be considered as another problem. Summary of the Invention

[0008] According to a first aspect of this disclosure, a polishing pad includes a base member comprising a first main surface and a second main surface opposite to the first main surface. The base member is plate-shaped and deformable. Polishing surfaces are disposed on the first main surface. A plurality of lines are disposed along the first main surface in the base member.

[0009] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of embodiments is given by way of example. Attached Figure Description

[0010] Figure 1 This is a schematic cross-sectional view illustrating the schematic structure of a polishing apparatus to which the polishing tool (polishing pad) of the embodiment is attached.

[0011] Figure 2 (A) is a cross-sectional view of the polishing pad of this embodiment, taken along a direction perpendicular to the pad surface.

[0012] Figure 2 (B) is a perspective plan view of the polishing pad of this embodiment viewed from a direction perpendicular to the pad surface.

[0013] Figure 3A It is a schematic cross-sectional view used to illustrate the creep deformation that occurs in a conventional polishing pad excluding lines.

[0014] Figure 3B This is a schematic cross-sectional view used to illustrate that almost no creep deformation occurs in the polishing pad of this embodiment.

[0015] Figure 4A Table 1 shows the evaluation results of the polishing pads for the comparative examples.

[0016] Figure 4B Table 2 shows the evaluation results of the polishing pad for Example 1.

[0017] Figure 5A Table 3 shows the evaluation results of the polishing pad for Example 2.

[0018] Figure 5B Table 4 shows the evaluation results of the polishing pad in Example 3. Detailed Implementation

[0019] Next, the polishing pads and the like of embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that since the embodiments described below are examples, those skilled in the art can appropriately modify the detailed construction, etc., without departing from the spirit of the present disclosure.

[0020] Furthermore, in the accompanying drawings referenced in the following embodiments and examples, unless otherwise stated, elements with the same reference numerals have the same function. Additionally, if multiple identical parts are shown in the figures, the symbols and descriptions assigned to some parts may be omitted.

[0021] Furthermore, for ease of description and explanation, the accompanying drawings may schematically illustrate components. Therefore, the shape, size, arrangement, etc., of the components shown in the drawings may not be strictly equivalent to the shape, size, arrangement, etc., of the corresponding actual components. Additionally, unless otherwise stated, expressions indicating a numerical range such as "equal to or greater than XX and equal to or less than YY" or "XX to YY" include both endpoint XX (lower limit) and endpoint YY (upper limit). Furthermore, in cases where numerical ranges are described in stages, the upper and lower limits of each numerical range may be appropriately combined with the upper and lower limits of another numerical range.

[0022] In the following description, the +X direction is equal to the direction indicated by the X-axis arrow in the orthogonal coordinate system shown in the figure, and the -X direction is equal to the direction 180 degrees opposite to the direction indicated by the X-axis arrow in the orthogonal coordinate system shown in the figure. Furthermore, when simply indicating the X direction, the X direction refers to the direction parallel to the X-axis, regardless of the direction indicated by the X-axis arrow in the figure. The same applies to directions other than the X direction.

[0023] Example Polishing device Figure 1This is a schematic cross-sectional view illustrating the schematic structure of a polishing apparatus to which a polishing pad (polishing tool) of an embodiment is attached. The polishing tool includes a polishing pad 6 and a frame 8. The polishing apparatus 1 includes a polishing pad 6, a frame 8 serving as a base for holding the polishing pad 6, a fluid storage section 9 for storing fluid for applying pressure from the lower surface side (i.e., the support surface side) of the polishing pad 6, and a polishing fluid supply section 2 for supplying polishing fluid 4 to the polishing surface of the polishing pad 6. The polishing apparatus 1 is a wet polishing apparatus in which the polishing pad 6 is supported by fluid pressure 7.

[0024] The fluid storage section 9, defined by the polishing pad 6 and the frame 8, has the function of storing a fluid (liquid or gas) capable of applying a predetermined pressure to the support surface of the polishing pad 6. The type of fluid is not limited to a specific type. If the fluid is a gas, the gas can be air, compressed air, or nitrogen. If the fluid is a liquid, the liquid can be pure water or polishing fluid. The level of the fluid pressure 7 applied to the polishing pad 6 is not limited to a specific level, and only needs to have a value that allows the fluid pressure 7 to support the polishing pad 6. For example, the level of the fluid pressure 7 is equal to or greater than 3 kPa and equal to or less than 40 kPa. The level of the fluid pressure 7 can be in the range of equal to or greater than 5 kPa and equal to or less than 20 kPa.

[0025] exist Figure 1 In the process, the workpiece carrier 3 applies pressure to the workpiece 5, which is the object to be polished. Figure 1 The downward force causes the workpiece 5 to press against the polishing surface of the polishing pad 6, which is then deformed upward by the fluid pressure 7. For example, the workpiece 5 is a semiconductor substrate or an optical lens, and the polishing surface of the polishing pad 6 can be deformed according to the shape of the workpiece 5.

[0026] Polishing pad Figure 2 (A) is a cross-sectional view of the polishing tool of this embodiment, taken along a direction perpendicular to the pad surface 11 used as the polishing surface. The polishing tool includes a polishing pad 6 and a frame 8 that supports the outer peripheral portion of the polishing pad 6. Figure 2 (B) is a perspective (transparent) plan view of the polished surface of polishing pad 6 viewed from the Z direction through the polishing pad. The pad surface 11, which serves as the polishing surface, constitutes one of the main surfaces of polishing pad 6.

[0027] In the polishing pad 6 of this embodiment, multiple lines 10 are embedded in a plate-shaped base member made of polyurethane foam or the like. Each of the multiple lines 10 can be referred to as a rope, thread, yarn, or fiber. That is, the multiple lines can be referred to as, for example, multiple ropes. In the polishing pad 6 of this embodiment, as... Figure 2 As shown in the cross-sectional view in (A), multiple lines 10 are arranged at a predetermined depth in a manner parallel to the pad surface 11. Furthermore, as... Figure 2As shown in (B), in the plan view, multiple lines 10 are arranged parallel to the pad longitudinal direction 14. The pad longitudinal direction 14 is the direction in which the longest line is obtained when the polishing pad 6 is viewed in the plan view from a direction perpendicular to the pad surface 11. Figure 2 In the example shown in (B), the polishing pad 6 has a circular shape in the plan view, and the diameter passing through the center of the circle corresponds to the pad longitudinal direction 14.

[0028] exist Figure 2 In the example shown in (B), the seven lines 10 are arranged parallel to the diameter extending in the X direction (i.e., the first direction) and parallel to the diameter extending in the Y direction (i.e., the second direction). However, the number and arrangement of the multiple lines 10 are not limited to the example above. For example, the multiple lines 10 may be arranged individually along a single direction, along three directions that differ from each other by 120 degrees in the plan view, or in another manner. In the case where the multiple lines 10 are arranged along two intersecting directions, as... Figure 2 As shown in (B), the multiple lines 10 can be arranged in two intersecting directions. Each line of the line 10 can extend from one side surface 12 of the polishing pad 6 to another side surface 12 opposite to the side surface 12. In other words, to improve creep resistance, the ends of each line of the multiple lines 10 can be arranged on the side surface of the base member.

[0029] When viewed through the pad surface 11, which serves as the polishing surface, from a direction perpendicular to the pad surface 11, the multiple lines 10 can be linear and arranged parallel to each other at predetermined intervals. The intervals 15 of the arrangement of the lines 10 (i.e., the predetermined intervals) can be equal to or less than 30 times the pad thickness 13. For example, when the pad thickness 13 is 1 mm, the intervals 15 of the side-by-side arrangement of the lines 10 can be equal to or less than 30 mm. Since the lines 10, which serve as structural members, are arranged within the matrix of the polishing pad 6, the creep deformation of the polishing pad 6 is reduced, as described below.

[0030] The material and thickness (i.e., diameter or denier) of each line 10 are selected such that the creep deformation of a single line 10 is less than the creep deformation of a narrow rectangular polishing pad excluding the lines, which is obtained by cutting the polishing pad excluding the lines at intervals equal to the spacing 15 of the lines 10 arranged in the polishing pad 6 (the width of the narrow rectangular polishing pad is equal to the respective intervals of the lines 10 arranged in the polishing pad 6). Specifically, the material and thickness of each line 10 are selected such that the creep deformation of a single line 10 is equal to or less than 10% of the creep deformation of the narrow rectangular polishing pad. That is, the creep deformation of a single line under external force is less than the creep deformation of a component having the same material and thickness as the base component of the polishing pad 6, having a width equal to the respective intervals of the lines 10 arranged in the polishing pad 6, and excluding the lines 10. For example, polyester-based fishing lines, which are generally readily available as fishing lines, can meet the above conditions. The diameter of the line 10 is less than the pad thickness 13. The diameter of the line 10 can be equal to or less than 10% of the pad thickness 13. For example, when the pad thickness 13 is 1 mm, the diameter φ of the line 10 can be equal to or less than 0.1 mm.

[0031] Furthermore, the material and thickness (i.e., diameter or denier) of each line 10 are selected such that the bending stiffness of a single line 10 is less than the bending stiffness of a narrow rectangular polishing pad excluding the lines. This polishing pad is obtained by cutting the polishing pad excluding the lines at intervals equal to the intervals 15 where the lines 10 are arranged side-by-side in the polishing pad 6 (the width of the narrow rectangular polishing pad is equal to the intervals where the lines 10 are arranged on the polishing pad 6). Specifically, the material and thickness of each line 10 are selected such that the bending stiffness of a single line 10 is equal to or less than 10% of the bending stiffness of the narrow rectangular polishing pad. That is, the bending stiffness of a single line against external forces is less than the bending stiffness of a component having the same material and thickness as the base component of the polishing pad 6, having a width equal to the intervals where the lines 10 are arranged in the polishing pad 6, and excluding the lines 10. For example, polyester-based fishing lines, which are generally readily available as fishing lines, can meet the above conditions.

[0032] Comparison with traditional polishing pads Figure 3A This is a schematic cross-sectional view used to illustrate the creep deformation that occurs when a workpiece 5 is polished using a conventional polishing pad 6X without the wires. Figure 3B This is a schematic cross-sectional view used to illustrate that when the workpiece 5 is polished using the polishing pad 6 of this embodiment, almost no creep deformation occurs.

[0033] If the polishing pad is expanded (i.e., enlarged) in the +Z direction by using fluid pressure, while simultaneously passing through the workpiece carrier 3 ( Figure 1When a force is applied to workpiece 5 in the -Z direction, workpiece 5 is polished while being pressed against the polishing surface. Tension is then applied along the longitudinal direction to the outer periphery PR of the polishing pad. If polishing is performed for an extended period using a conventional polishing pad (i.e., polishing pad 6X excluding the wires), then... Figure 3A As illustrated, irreversible creep deformation occurs, particularly in the outer peripheral portion (PR) of the polishing pad. If the polishing pad is stretched in the longitudinal direction, it will warp during polishing, and the polished surface of the pad will not make uniform contact with the workpiece. As a result, the polishing accuracy will deteriorate. Therefore, in conventional methods where the polishing pad is fluid-supported without wires, it is impossible to maintain high follow-through for extended periods.

[0034] In contrast, in the polishing pad 6 of this embodiment, the polishing pad 6 includes multiple lines extending from one edge of the polishing pad 6 to the other parallel to the longitudinal direction in a planar view. Even when the workpiece 5 is pressed against the polishing surface, and the workpiece 5 is polished by using the pressure of fluid to cause the polishing pad 6 to expand (i.e., expand or enlarge) in the +Z direction, creep deformation hardly occurs. Therefore, compared with conventional polishing pads, the polishing pad of this embodiment can maintain high followability for a long time.

[0035] Examples and comparisons Next, specific examples will be described. First, methods for evaluating polishing pads and methods for evaluating the results of polishing workpieces will be described, followed by comparative examples and illustrations using conventional polishing pads.

[0036] Evaluation methods for polishing pads Relative creep deformation of line to polishing pad For each of the single-line and non-line-exclusive narrow rectangular polishing pads, a constant-load tensile creep test (JIS K6273) was performed, and the creep rate E3 was calculated. This narrow rectangular polishing pad was obtained by cutting the non-line-exclusive polishing pad at intervals equal to the spacing 15 of the line 10 arranged in the polishing pad 6. Note that the gauge length is 100 mm and the load is 1 N.

[0037] Creep rate E3 = (L4 - L3) / (L3 - L0) × 100 in, L0: Gauge length obtained before the experiment L3: Gauge length obtained after 5 hours of applying load, and... L4: Gauge length obtained after 10 hours of applying load.

[0038] The creep rate of a single line calculated using the above equation is defined as E. 3-ITO The creep rate of a single polishing pad, calculated using the above equation, is defined as E. 3-PAD And based on the creep rate E3-ITO With creep rate E 3-PAD The ratio is used to calculate the relative creep deformation (%) of a single line to a single polishing pad.

[0039] The relative creep deformation (%) of the line to the polishing pad = E 3-ITO / E 3-PAD ×100 in, E 3-ITO The creep rate of a single line, and, E 3-PAD : Creep rate of a single polishing pad.

[0040] Relative bending stiffness of line-to-polishing pad For each of the single-line and excluding-line narrow rectangular polishing pads, a cantilever bending test is performed. The narrow rectangular polishing pads are obtained by cutting the excluding-line polishing pads at intervals equal to the intervals 15 where lines 10 are arranged in the polishing pad 6. The upper end of the test piece is supported, and the test piece is suspended vertically downwards. The lower end of the test piece is pushed horizontally a predetermined distance, and the reaction force obtained when the lower end has been pushed the predetermined distance is measured. The bending stiffness M is calculated based on the reaction force. Note that the distance from the position supporting the upper end of the test piece to the position where the lower end of the test piece is pushed is 100 mm, and the displacement of the test piece by the push is 10 mm.

[0041] Bending stiffness M=P / X in, P: The reaction force obtained when the lower end of the test piece has been pushed a predetermined distance in the horizontal direction, and, X: Displacement by which the lower end of the test piece is pushed a predetermined distance in the horizontal direction.

[0042] The bending stiffness of a single line calculated using the above equation is defined as M. ITO The bending stiffness of a single polishing pad, calculated using the above equation, is defined as M. PAD And based on the bending stiffness M ITO With bending stiffness M PAD The ratio is used to calculate the relative bending stiffness (%) between a single line and a single polishing pad.

[0043] Relative bending stiffness (%) of line-to-polishing pad = M ITO / M PAD ×100 in, M ITO The bending stiffness of a single line, and M PAD : Bending stiffness of a single polishing pad.

[0044] Evaluation methods for polished workpiece results Changes in polishing results due to prolonged use of polishing pads The workpieces were continuously polished for 24 hours while the slurry was being applied. Each workpiece was a glass substrate with a surface roughness of 50 nm Rz and a diameter of φ of 80 mm, and a new workpiece was replaced every 30 minutes. The slurry was cerium oxide (MIREK K30-9). As described above, the workpieces were removed every two hours, and the maximum surface roughness Rz of the workpieces was evaluated. In this way, the change in workpiece surface roughness relative to the continuous use time of the polishing pad was evaluated.

[0045] workpiece surface roughness Surface roughness of the workpiece was measured using a white light interferometer (CP300 manufactured by Zygo Corporation). Specifically, a portion of the test workpiece (φ80 mm) was measured using a 5x objective lens, and the maximum roughness Rz (JIS B 0601-2001) of the entire measured portion was evaluated. This portion of the test workpiece was the area between a point 35 mm from the center of the test workpiece on the left and a point 35 mm from the center of the test workpiece on the right. The resolution was 0.01 nm.

[0046] Determination of follow-up Based on the workpiece surface roughness value, it is determined whether the polishing pad has followed the workpiece. If the polishing pad does not follow the workpiece and cannot polish the workpiece uniformly, unpolished portions are left, and the workpiece surface roughness will not be equal to or less than 1 nmRz. Therefore, when the workpiece surface roughness is equal to or less than 1 nmRz, high following performance is determined.

[0047] Comparative example using traditional polishing pads In the comparative example, a conventional polishing pad is used. The polishing pad is used for polishing in a fluid-supported configuration. In the polishing pad, a polishing layer with a polishing surface and a sealing layer with a supporting surface are sequentially arranged, with the polishing surface serving as the front surface and the supporting surface serving as the rear surface. Next, a method for manufacturing a conventional polishing pad will be described.

[0048] 28.98 g of thermoplastic resin diphenylmethane diisocyanate (MDI) type polyurethane elastomer Coronate 4370 (manufactured by Tosoh Corporation) was weighed as the resin material for the sealing layer; 20.28 g of polyol-based curing agent Nipolon 4479 (manufactured by Tosoh Corporation) was weighed as the curing agent; and the resin material and curing agent were mixed together. 0.78 g of Matsumoto Microsphere FN-78D (manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) and 3.06 g of polytetrafluoroethylene particles ALGOFLON L203R (manufactured by Solvey) were added to the mixture as the first hollow particles. These materials were mixed together using an AS100 (2-913-01) automatic mixer (manufactured by AS ONE Corporation, with a rotation speed of 3000 rpm). Three mixing operations were performed over a total time of 48 seconds (each requiring 16 seconds for minimal heat impact), thus preparing the sealing layer precursor.

[0049] Similarly, 28.98 g of thermoplastic diphenylmethane diisocyanate (MDI) type polyurethane elastomer Coronate 4370 (manufactured by Tosoh Corporation) was weighed as the resin material for the polishing layer; 20.28 g of polyol-based curing agent Nipolon 4479 (manufactured by Tosoh Corporation) was weighed as the curing agent; and the resin material and curing agent were mixed together. 0.99 g of Matsumoto Microsphere F-80DE (manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.) was added to the mixture as the third hollow particle. These materials were mixed together using an AS100 (2-913-01) automatic mixer (manufactured by AS ONE Corporation, with a rotation speed of 3000 rpm). Three mixing operations were performed over a total of 48 seconds (each requiring 16 seconds for minimal heat impact), thus preparing the polishing layer precursor.

[0050] Next, 8.0g of the sealing layer precursor was placed into a square mold with a bottom surface size of 200mm × 200mm and pre-cured in an electric furnace at 120°C for 10 minutes. Then, 24.0g of the polishing layer precursor was placed on the pre-cured sealing layer precursor and initially cured in an electric furnace at 120°C for one hour. Afterward, the pre-cured polishing pad precursor was released from the mold. Then, the polishing pad precursor was second-cured at 120°C for 8 hours to obtain the comparative example polishing pad. The thickness of the polishing pad was 0.96mm (of which the sealing layer thickness was 0.33mm and the polishing layer thickness was 0.63mm).

[0051] The changes in the polishing results of the workpiece caused by the polishing pad of the comparative example used for a long time were evaluated using the evaluation method described above. Figure 4A Table 1 shows the variation of workpiece surface roughness with respect to the continuous use time of the polishing pad in the comparative example.

[0052] In Table 1, with a continuous pad usage time of 2 hours, the workpiece surface roughness of the comparative example polishing pad was 0.70 nmRz. Therefore, the polishing pad exhibited high followability at the start of polishing. However, thereafter, the workpiece surface roughness deteriorated with increasing continuous pad usage time. At the point when the continuous pad usage time reached 10 hours, the workpiece surface roughness became greater than 1 nmRz, which is the value used to determine followability. Therefore, the comparative example polishing pad maintained high followability only when the continuous usage time was as long as 8 hours.

[0053] Example 1 Next, an example will be described below. In Example 1, in a polishing pad having the same external shape as the comparative example, a line is laid between a polishing layer as a first layer and a sealing layer as a second layer. The polishing layer and the sealing layer form a plate-like deformable base member. The line used is a synthetic fiber made of polyethylene resin and is PE line 0.1, which is commonly and easily obtained as fishing line. The line diameter is 0.054 mm, which is 5.6% of the polishing pad thickness of 0.96 mm. Therefore, the line diameter can satisfy the condition that the line diameter is equal to or less than 10% of the polishing pad thickness.

[0054] With each line linearly stretched, when viewed from above, the polishing pad surface appears as if these lines are arranged side-by-side, extending in one direction at regular intervals. The interval between each side-by-side line is 20 mm. This interval is 20.8 times the thickness of the polishing pad (i.e., 0.96 mm). Therefore, the line spacing can satisfy the condition that the line spacing is equal to or less than 30 times the thickness of the polishing pad.

[0055] The relative creep deformation of the line relative to the narrow polishing pad excluding the line is 3.2%. This narrow polishing pad is obtained by cutting the polishing pad excluding the line at 20mm intervals, which is equal to the interval 15 where the lines are arranged side-by-side in the polishing pad 6. Therefore, the relative creep deformation of the line satisfies the condition that the relative creep deformation is equal to or less than 10%. Furthermore, the relative bending stiffness of the line relative to the narrow polishing pad excluding the line is 1.2%. This narrow polishing pad is obtained by cutting the polishing pad excluding the line at 20mm intervals, equal to the interval 15 where the lines are arranged side-by-side in the polishing pad 6. Therefore, the relative bending stiffness of the line satisfies the condition that the relative bending stiffness is equal to or less than 10%.

[0056] The polishing pad in this example is manufactured by laying lines during the same manufacturing process as that of the comparative example. Specifically, the sealant precursor is first pre-cured, then lines are laid on the surface of the sealant precursor, and then the polishing precursor is placed on the lines.

[0057] The changes in the polishing results of the polishing workpiece caused by the polishing pad of Example 1 used for a long time were evaluated using the evaluation method described above. Figure 4B Table 2 shows the variation of workpiece surface roughness with respect to the continuous use time of the polishing pad in Example 1.

[0058] In Table 2, when the continuous pad usage time of the polishing pad in Example 1 is 2 hours, the workpiece surface roughness is 0.71 nmRz, which is essentially equal to the workpiece surface roughness of the comparative example. Furthermore, when using the polishing pad in Example 1, the workpiece surface roughness deteriorates with increasing continuous pad usage time. However, the rate of deterioration is slower compared to the rate in the comparative example; and at the point where the continuous pad usage time reaches 18 hours, the workpiece surface roughness exceeds 1 nmRz, which is the value used to determine followability. Therefore, even with a continuous usage time of up to 16 hours (8 hours longer than the continuous usage time of the comparative example), the polishing pad in Example 1 maintains high followability.

[0059] Example 2 Similarly, in Example 2, in a polishing pad having the same external shape as the comparative example, a line is laid between a polishing layer as a first layer and a sealing layer as a second layer. The polishing layer and the sealing layer form a plate-like deformable base member. The line used is a synthetic fiber made of polyethylene resin, specifically PE line 0.1, which is commonly and readily available as fishing line. The line diameter is 0.054 mm, which is 5.6% of the polishing pad thickness of 0.96 mm. Therefore, the line diameter satisfies the condition that the line diameter is equal to or less than 10% of the polishing pad thickness.

[0060] With each line linearly stretched, when the surface of the polishing pad is viewed from above, these lines are arranged side-by-side, extending in one direction at regular intervals. The intervals between these side-by-side lines are 10 mm, shorter than the intervals in Example 1. This interval is 10.4 times the polishing pad thickness of 0.96 mm. Therefore, the line intervals can satisfy the condition that the line interval is equal to or less than 30 times the polishing pad thickness. The relative creep deformation of the lines relative to the narrow polishing pad excluding the lines is 1.6%, obtained by cutting the polishing pad excluding the lines at intervals equal to the 10 mm intervals between the lines arranged side-by-side in polishing pad 6. Therefore, the relative creep deformation of the lines can satisfy the condition that the relative creep deformation is equal to or less than 10%. Furthermore, the relative bending stiffness of the lines relative to the narrow polishing pad excluding the lines is 1.4%, obtained by cutting the polishing pad excluding the lines at intervals equal to the 10 mm intervals between the lines arranged side-by-side in polishing pad 6. Therefore, the relative bending stiffness of the line can meet the condition that the relative bending stiffness is equal to or less than 10%.

[0061] The polishing pad of Example 2 is manufactured by laying lines during the same manufacturing process as that of the comparative example. Specifically, the sealing layer precursor is pre-cured, then lines are laid on the surface of the sealing layer precursor, and then the polishing layer precursor is placed on the lines.

[0062] The changes in the polishing results of the polishing workpiece caused by the polishing pad of Example 2 used for a long time were evaluated using the evaluation method described above. Figure 5A Table 3 shows the change in workpiece surface roughness relative to the continuous use time of the polishing pad in Example 2.

[0063] In Table 3, when using the polishing pad of Example 2, the workpiece surface roughness obtained after a continuous pad usage time of 2 hours was 0.72 nmRz, which is essentially equal to the workpiece surface roughness of the comparative example. Furthermore, when using the polishing pad of Example 2, the workpiece surface roughness deteriorated with increasing continuous pad usage time. However, compared to the rate in Example 1, the rate of deterioration was further reduced; and at the point where the continuous pad usage time reached 22 hours, the workpiece surface roughness exceeded 1 nmRz, which is the value used to determine followability. Therefore, even with a continuous usage time of up to 20 hours (12 hours longer than the continuous usage time of the comparative example and 4 hours longer than the continuous usage time of Example 1), the polishing pad of Example 2 maintained high followability.

[0064] Example 3 Similarly, in Example 3, in a polishing pad having the same external shape as the comparative example, a line is laid between a polishing layer as a first layer and a sealing layer as a second layer. The polishing layer and the sealing layer form a plate-shaped deformable base member. The line used is a synthetic fiber made of polyethylene resin and is PE line 0.1, which is commonly available as fishing line. The line diameter is 0.054 mm, which is 5.6% of the polishing pad thickness of 0.96 mm. Therefore, the line diameter can satisfy the condition that the line diameter is equal to or less than 10% of the polishing pad thickness.

[0065] With each line linearly stretched, when viewed from above, the polishing pad surface appears as if these lines are arranged side-by-side at regular intervals, extending in two mutually orthogonal directions. The interval between each side-by-side line is 10 mm, equal to the interval in Example 2. This interval is 10.4 times the polishing pad thickness of 0.96 mm. Therefore, the line intervals satisfy the condition that the line interval is equal to or less than 30 times the polishing pad thickness. The relative creep deformation of the lines relative to the narrow polishing pad excluding the lines is 1.6%, obtained by cutting the polishing pad excluding the lines at intervals equal to the 10 mm intervals between the lines arranged side-by-side in polishing pad 6. Therefore, the relative creep deformation of the lines satisfies the condition that the relative creep deformation is equal to or less than 10%. Furthermore, the relative bending stiffness of the lines relative to the narrow polishing pad excluding the lines is 1.4%, obtained by cutting the polishing pad excluding the lines at intervals equal to the 10 mm intervals between the lines arranged side-by-side in polishing pad 6. Therefore, the relative bending stiffness of the line can meet the condition that the relative bending stiffness is equal to or less than 10%.

[0066] The polishing pad of Example 3 is manufactured by laying lines during the same manufacturing process as that of the comparative example. Specifically, the sealing layer precursor is pre-cured, then lines are laid on the surface of the sealing layer precursor, and then the polishing layer precursor is placed on the lines.

[0067] The changes in the polishing results of the polishing workpiece caused by the polishing pad of Example 3 after long-term use were evaluated using the evaluation method described above. Figure 5B Table 4 shows the change in workpiece surface roughness relative to the continuous use time of the polishing pad in Example 3.

[0068] In Table 4, when using the polishing pad of Example 3, the workpiece surface roughness obtained after a continuous pad usage time of 2 hours is 0.73 nmRz, which is essentially equal to the workpiece surface roughness of the comparative example. Furthermore, when using the polishing pad of Example 3, the workpiece surface roughness deteriorates with increasing continuous pad usage time. However, compared to the rate in Example 2, the rate of deterioration is further reduced; and even at the point where the continuous pad usage time reaches 24 hours, the workpiece surface roughness is equal to or less than 1 nmRz, a value used to determine followability. Therefore, the polishing pad of Example 3 maintains high followability even with a continuous usage time of up to 24 hours (16 hours longer than the continuous usage time of the comparative example, 8 hours longer than the continuous usage time of Example 1, and 4 hours longer than the continuous usage time of Example 2).

[0069] As described above, in this disclosure, the line is included in a fluid-supported polishing pad. As a result, almost no creep deformation occurs in the polishing pad, thus maintaining high responsiveness even with prolonged continuous use. Therefore, the polishing pad of this disclosure is able to polish workpieces without degrading their surface roughness, compared to conventional fluid-supported polishing pads.

[0070] Note that this disclosure is not limited to the above embodiments and examples, and various modifications can be made within the technical concept of this disclosure. Furthermore, the effects described in the embodiments are merely examples of the most suitable effects produced by this disclosure. Therefore, the effects of this disclosure are not limited to those described in the embodiments.

[0071] Note that this disclosure is not limited to the above embodiments and examples, and various modifications can be made within the technical concept of this disclosure. For example, some or all of the different embodiments and examples described above can be combined with each other and implemented.

[0072] Furthermore, the disclosure in this specification includes not only what is described herein, but also all items that can be understood from this specification and its accompanying drawings. In addition, the disclosure in this specification includes a set of complementary concepts described herein. Therefore, if this specification contains a description indicating, for example, "A is B," it can be said that this specification discloses a description indicating "A is not B," even if the description indicating "A is not B" is omitted. This is because the presence of a description indicating "A is B" presupposes the possibility that "A is not B."

[0073] Other embodiments While this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such variations and equivalent structures and functions.

Claims

1. A polishing pad comprising: A base component includes a first main surface and a second main surface opposite to the first main surface. The base component is plate-shaped and deformable, and polished surfaces are arranged on the first main surface. Multiple lines are arranged along the first main surface in the base member.

2. The polishing pad according to claim 1, wherein, When the plurality of lines are viewed through the first main surface from a direction perpendicular to the first main surface, at least a portion of the plurality of lines are arranged side by side to extend along the first main surface in a first direction.

3. The polishing pad according to claim 1, wherein, When the plurality of lines are viewed through the first main surface from a direction perpendicular to the first main surface, the first line of the plurality of lines is arranged along a first direction, and the second line of the plurality of lines is arranged along a second direction intersecting the first direction.

4. The polishing pad according to any one of claims 1 to 3, wherein, When the plurality of lines are viewed through the first main surface from a direction perpendicular to the first main surface, each of the plurality of lines is arranged along a straight line.

5. The polishing pad according to any one of claims 1 to 3, wherein, Each of the multiple lines is positioned at a depth separate from the polished surface.

6. The polishing pad according to any one of claims 1 to 3, wherein, The ends of each of the multiple lines are arranged on the side surface of the base member.

7. The polishing pad according to any one of claims 1 to 3, wherein, When the plurality of lines are viewed through the first main surface from a direction perpendicular to the first main surface, the plurality of lines include a first plurality of lines and a second plurality of lines, wherein the first plurality of lines are arranged to intersect with the second plurality of lines.

8. The polishing pad according to claim 2 or 3, wherein, In the plan view of the first main surface, the first direction is the longitudinal direction in which the base member has the longest length.

9. The polishing pad according to any one of claims 1 to 3, wherein, The diameter of each of the multiple lines is smaller than the thickness of the base component.

10. The polishing pad according to claim 9, wherein, The diameter of each of the multiple lines is equal to or less than 10% of the thickness of the base member.

11. The polishing pad according to any one of claims 1 to 3, wherein, When the plurality of lines are viewed through the first main surface from a direction perpendicular to the first main surface, adjacent lines among the plurality of lines are arranged at intervals.

12. The polishing pad according to claim 11, wherein, The distance between each interval is equal to or less than 30 times the thickness of the base member.

13. The polishing pad according to claim 11, wherein, The creep deformation of each of the multiple lines caused by external force is less than the creep deformation of a member excluding the lines, having the same material and thickness as the base member and having a width equal to the width of each interval.

14. The polishing pad according to claim 13, wherein, The creep deformation of each of the multiple lines caused by external force is equal to or less than 10% of the creep deformation of the component excluding the lines.

15. The polishing pad according to claim 11, wherein, The bending stiffness of each of the multiple lines caused by external force is less than the bending stiffness of a member excluding the lines, having the same material and thickness as the base member and having a width equal to the width of each interval.

16. The polishing pad according to claim 15, wherein, The bending stiffness of each of the multiple lines caused by external force is equal to or less than 10% of the bending stiffness of the member excluding the lines.

17. The polishing pad according to any one of claims 1 to 3, wherein, The base component comprises thermoplastic resin or polyurethane foam, and each of the multiple lines is a synthetic fiber.

18. A polishing tool comprising: Polishing pad according to any one of claims 1 to 17; as well as A frame, which is configured to support the outer peripheral portion of the base member, The fluid storage portion, configured to store fluid on the second main surface side, is defined by the polishing pad and the frame. The base member is configured such that when the second main surface receives pressure from the fluid, the first main surface deforms in the direction opposite to that of the fluid storage portion.

19. A polishing apparatus comprising: Polishing pad according to any one of claims 1 to 17; as well as The polishing fluid supply unit is configured to supply polishing fluid to the polishing surface of the polishing pad.

20. A polishing method for polishing a workpiece using a polishing pad according to any one of claims 1 to 17, the polishing method comprising: The workpiece is polished by pressing the polishing surface against it, and the polishing surface is deformed by applying pressure to the second main surface using a fluid.

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