Method for trimming polishing pad, method for polishing silicon wafer, method for manufacturing silicon wafer, and apparatus for polishing silicon wafer

Abstract

Provided is a polishing pad dressing method capable of more uniformly dressing a polishing pad even when the surface of a rotating platform is curved. A method for dressing a polishing pad (100), in which a grindstone (12) of a pad dresser (1) to which the grindstone (12) is attached is pressed against the polishing pad (100) affixed to a polishing platform, and the grindstone (12) is brought into sliding contact with the polishing pad (100), whereby the polishing pad (100) is dressed. The radius of curvature (R1) of the dressing surface (12b) of the grindstone (12), which is in sliding contact with the polishing pad (100), in the radial direction of the polishing platform can be changed.

Description

Technical Field

[0001] The present invention relates to a dressing method for a polishing pad, a polishing method for a silicon wafer, a manufacturing method for a silicon wafer and a polishing device for a silicon wafer. Background Art

[0002] In the manufacture of silicon wafers, which are a typical example of substrates for semiconductor devices, in order to obtain higher precision flatness quality and surface roughness quality of the wafer, a double-side grinding process of grinding the front and back sides of the silicon wafer and a single-side grinding process of grinding one of the front and back sides of the silicon wafer are generally adopted.

[0003] In the double-sided polishing process, the silicon wafer is held on a carrier, and the carrier is clamped by a pair of rotating platforms consisting of an upper platform and a lower platform with a polishing pad attached to them. The rotating platform and the carrier are rotated relative to each other while supplying polishing liquid, thereby polishing the front and back sides of the silicon wafer at the same time.

[0004] On the other hand, in the single-side polishing process, a silicon wafer is placed on a rotating platform with a polishing pad attached thereto, the silicon wafer is pressed with a polishing head, and the rotating platform and the polishing head are rotated relative to each other while supplying polishing liquid, thereby polishing one of the front and back sides of the silicon wafer.

[0005] If the above-mentioned double-sided grinding process or single-sided grinding process is repeatedly performed, the abrasive grains and grinding chips contained in the grinding liquid adhere to the grinding pad attached to the rotating platform, the performance of the grinding pad is reduced, and problems such as a reduction in grinding speed and uneven grinding occur. Therefore, in order to restore the performance of the grinding pad, the grinding pad is regularly subjected to dressing treatment.

[0006] For example, the following technology is recorded in patent document 1: a diamond dresser having diamond particles electrodeposited on the lower surface is pushed against a grinding pad and the diamond dresser is brought into sliding contact with the grinding pad to roughen the surface of the grinding pad; then a brush dresser having a brush on the lower surface is pushed against the grinding pad and the brush dresser is brought into sliding contact with the grinding pad, thereby, even when the grinding surface of the grinding pad is provided with a recess, foreign matter clogged in the recess is effectively removed and the grinding pad is regenerated.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2003-211355 Summary of the invention

[0010] Problems to be solved by the invention

[0011] In the technology described in Patent Document 1, the dressing surface of the dresser is flat. When the polishing pad is dressed using such a dresser with a flat dressing surface, differences occur in the radial pushing method at the inner and outer ends of the rotating platform according to the installation accuracy of the dresser and the angle when pressurizing, resulting in deviations in the machining allowance in the radial direction of the rotating platform. In addition, when the surface of the rotating platform is a curved shape such as a bowl or an inverted bowl, the ends of the dresser are pushed against the polishing pad more strongly at the inner and outer ends of the rotating platform, which also results in deviations in the machining allowance in the radial direction of the rotating platform.

[0012] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a polishing pad dressing method capable of dressing the polishing pad more uniformly even when the surface of a rotating table is curved.

[0013] Means used to solve problems

[0014] [1] A method for dressing a polishing pad, comprising: pushing the polishing tool of a pad dresser with a polishing tool against a polishing pad adhered to a polishing platform and making the polishing tool and the polishing pad in sliding contact, thereby dressing the polishing pad, characterized in that the pad dresser is used: the curvature radius R1 of the dressing surface of the polishing tool in sliding contact with the polishing pad in the radial direction of the polishing platform can be changed.

[0015] [2] The method for dressing a polishing pad as described in [1] above, wherein the curvature radius R1 of the dressing surface of the grinding tool is changed to be smaller than the curvature radius R2 of the surface of the polishing pad, and then the polishing pad is dressed.

[0016] [3] A method for dressing a polishing pad as described in [1] or [2] above, using the following pad dresser: the aforementioned grinding tool has multiple dressing surfaces with different curvature radii, and by rotating the aforementioned grinding tool, the aforementioned curvature radius R2 of the aforementioned dressing surface in sliding contact with the aforementioned polishing pad can be changed.

[0017] [4] The method for dressing a polishing pad as described in [1] or [2] above uses the following pad dresser: the base material of the grinding tool is made of a flexible alloy, and the curvature radius R1 of the dressing surface can be changed by pushing the grinding tool from the opposite side of the dressing surface.

[0018] [5] The grinding pad dressing method as described in [4] above uses the following pad dresser: the grinding tool is attached to the pad dresser via a retaining member, both ends of the base material of the grinding tool are connected to the retaining member, and the curvature radius R1 of the dressing surface can be changed by pushing a part of the grinding tool on the opposite side of the dressing surface with a pushing member.

[0019] [6] The method for dressing a polishing pad as described in [4] above uses the following pad dresser: the abrasive tool is attached to the pad dresser via a retaining member having a thermal expansion coefficient different from that of the base material of the abrasive tool, and the curvature radius R1 of the dressing surface can be changed by changing the temperature of the retaining member.

[0020] [7] A method for polishing a silicon wafer, characterized in that the silicon wafer is polished using a polishing pad, wherein the polishing pad is a polishing pad that has been dressed using the polishing pad dressing method described in any one of [1] to [6] above.

[0021] [8] A method for manufacturing a silicon wafer, characterized in that the silicon wafer is polished using the silicon wafer polishing method described in [7] above, wherein the silicon wafer is obtained by performing wafer processing on a single crystal silicon ingot grown by a prescribed method.

[0022] [9] A silicon wafer polishing device, comprising a polishing platform, a polishing pad adhered to the polishing platform, and a pad dresser with a grinding tool attached thereto for dressing the polishing pad, wherein the curvature radius R1 of the dressing surface of the grinding tool in sliding contact with the polishing pad in the radial direction of the polishing platform can be changed.

[0023]

[10] In the silicon wafer polishing device described in [9] above, the grinding tool has a plurality of trimming surfaces having different curvature radii, and is configured so that the curvature radius R1 of the trimming surface in sliding contact with the polishing pad can be changed by rotating the grinding tool.

[0024]

[11] In the silicon wafer polishing device described in

[10] above, the base material of the grinding tool is made of a bendable alloy, and the curvature radius R1 of the dressing surface can be changed by pressing the grinding tool from the opposite side of the dressing surface.

[0025]

[12] In the silicon wafer grinding device as described in

[11] above, the grinding tool is attached to the pad dresser via a retaining member, and both ends of the base material of the grinding tool are connected to the retaining member, so that the curvature radius R1 of the dressing surface can be changed by pushing a part of the grinding tool on the opposite side of the dressing surface with a pushing member.

[0026]

[13] In the silicon wafer grinding device as described in

[11] above, the grinding tool is attached to the pad dresser via a retaining member having a thermal expansion coefficient different from that of the base material of the grinding tool, and is configured so that the curvature radius R1 of the dressing surface can be changed by changing the temperature of the retaining member.

[0027] Effects of the Invention

[0028] Even when the surface of the rotating platform is curved, the polishing pad can be dressed more uniformly. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figures are for explaining the dressing method of the polishing pad according to the present invention, (a) is a perspective view, and (b) is a plan view.

[0030] Figure 2 It is a diagram for explaining the curvature radius of the dressing surface of the grinding tool and the curvature radius of the polishing pad.

[0031] Figure 3 This is a diagram showing an example of a pad dresser that can be used in the present invention and is configured so that the curvature radius of the dressing surface of the grinding wheel can be changed.

[0032] Figure 4 This is a diagram showing another example of a pad dresser that can be used in the present invention and is configured so that the curvature radius of the dressing surface of the grinding wheel can be changed.

[0033] Figure 5 This is a diagram showing still another example of a pad dresser that can be used in the present invention and is configured so that the curvature radius of the dressing surface of the grinding wheel can be changed.

[0034] Figure 6 This is a diagram showing still another example of a pad dresser that can be used in the present invention and is configured so that the curvature radius of the dressing surface of the grinding wheel can be changed. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The dressing method of a polishing pad according to the present invention is a dressing method of a polishing pad that performs dressing of the polishing pad by pushing a grinding tool of a pad dresser with a grinding tool against a polishing pad attached to a polishing platform and making the grinding tool and the polishing pad in sliding contact. Here, it is characterized in that the following pad dresser is used: it is configured so that the curvature radius R1 of the dressing surface of the grinding tool in sliding contact with the polishing pad in the radial direction of the polishing platform can be changed.

[0036] As described above, if the polishing pad is dressed using a dresser with a flat dressing surface as in the technique described in Patent Document 1, differences occur in the radial pushing method at the inner and outer ends of the rotating platform depending on the installation accuracy of the dresser and the angle at which the pressurization is applied, and there is a problem of deviation in the machining allowance in the radial direction of the rotating platform. In addition, when the surface of the rotating platform is a curved shape such as a bowl or an inverted bowl, the end of the dresser is pushed against the polishing pad more strongly at the inner and outer ends of the rotating platform, and there is also a problem of deviation in the machining allowance in the radial direction of the rotating platform.

[0037] The present inventors have conducted intensive research on a method for dressing the grinding pad more evenly even when the surface of the rotating platform is curved. As a result, they came up with the idea of ​​using the following pad dresser: the curvature radius R1 of the dressing surface of the grinding tool in sliding contact with the grinding pad in the radial direction of the grinding platform (hereinafter, simply referred to as "the curvature radius of the dressing surface") can be changed. Then, it was found that by using such a pad dresser, the curvature radius of the dressing surface can be changed to match the curvature of the rotating platform, thereby being able to dress the grinding pad with a certain pushing pressure, and the present invention was completed.

[0038] Figure 1 The figures for explaining the dressing method of the polishing pad according to the present invention are shown, (a) is a perspective view, and (b) is a top view. Figure 1 The following describes the condition in which the polishing pad 100 attached to the surface of the lower platform of the double-sided polishing device is trimmed. Figure 1 As shown in (a), the pad dresser 1 comprises an arm 11 and a grinding tool 12 attached to the arm 11, and the grinding tool 12 is fixed to the end 11a of the arm 11 via a holder 13. In addition, the grinding tool 12 is composed of a base material 12a and abrasive grains (not shown) bonded to the surface of the base material 12a, and the abrasive grains are bonded to at least the dressing surface 12b of the grinding tool 12.

[0039] The curvature radius R1 of the dressing surface 12b of the grinding tool 12 can be changed. Thus, by changing the curvature radius R1 of the dressing surface 12b to match the curvature of the rotating platform, the grinding pad 100 can be dressed with a certain pressing pressure, and the grinding pad 100 can be dressed more uniformly. The specific pad dresser 1 capable of changing the curvature radius R1 will be described in detail later.

[0040] In the present invention, the so-called "dressing surface of the grinding tool" refers to the surface of the grinding tool 12 that is in sliding contact with the grinding pad 100 when the grinding pad 100 is dressed. Figure 1 In the embodiment, the finishing surface 12b is the entire lower surface of the grinding tool 12. In addition, the "curvature radius of the finishing surface" is as follows: Figure 2 As shown, it refers to the radius R1 of the arc when the radial surface profile of the grinding platform is fitted to the arc on the dressing surface 12b of the grinding tool 12 in sliding contact with the grinding pad 100. In addition, the surface profile of the dressing surface 12b can be measured using a commercially available non-contact shape measuring device, etc. In addition, the arc fitting can be performed by the least square method, etc.

[0041] like Figure 1 As shown in (b), the pad dresser 1 configured as described above is moved from one of the inner end and the outer end of the lower platen toward the other while the lower platen is rotated, thereby dressing the entire polishing pad 100 .

[0042] In addition, in the present invention, it is preferred that the radius of curvature R1 of the dressing surface 12b of the grinding tool 12 is changed to be smaller than the radius of curvature R2 of the surface of the grinding pad 100, and then the grinding pad 100 is dressed. By making the radius of curvature R1 of the dressing surface 12b smaller than the radius of curvature R2 of the surface of the grinding pad 100, dressing can be performed with a more certain pushing pressure, and the grinding pad 100 can be dressed more evenly. The radius of curvature R1 of the dressing surface 12b is preferably set to more than 10mm. Thus, the contact area between the grinding tool 12 and the grinding pad 100 can be fully ensured, and the entire grinding pad 100 can be evenly and efficiently performed.

[0043] In addition, the "radius of curvature of the polishing pad" is Figure 2 As shown, it refers to the radius R2 of the arc when the radial surface profile of the grinding platform is fitted with an arc with respect to the surface 100a of the grinding pad 100. Here, the surface profile is the profile of the entire surface from one end (e.g., the inner end) to the other end (e.g., the outer end) of the grinding pad 100. The surface profile of the grinding pad 100 can be measured using a commercially available non-contact shape measuring machine and a dedicated surface profiler. In addition, the arc fitting can be performed by the least square method, etc.

[0044] Figure 3 An example of a pad dresser that can be used in the present invention and is configured such that the curvature radius of the dressing surface of the grinding wheel can be changed is shown. Figure 3 The pad dresser 2 shown in (a) includes a grinding tool 22, and the grinding tool 22 has a base material 22a and abrasive grains (not shown) fixed to at least the dressing surface of the base material 22a. In addition, the grinding tool 22 has four dressing surfaces 22b (curvature radius: 50.0 mm), 22c (curvature radius: 100.0 mm), 22d (curvature radius: 250.0 mm) and 22e (curvature radius: 500.0 mm) with different curvature radii.

[0045] Abrasive tool 22 Figure 3 As shown in (b), the arm 21 is connected via the rotating shaft 23 and the cylinder 24. And it is configured so that the curvature radius R1 of the dressing surface can be changed by rotating the grinding tool 22 around the rotating shaft 23 in the radial direction of the platform. Figure 3 (c) can be fixed by threaded locking.

[0046] As the base material of the grinding wheel 22, for example, SUS with a DLC coating applied to the surface can be used. In addition, as the abrasive grains, for example, diamond abrasive grains and ceramic abrasive grains can be used.

[0047] In the pad dresser 2 having such a structure, the dressing surface of the grinding tool 22 is appropriately selected to match the surface shape of the grinding platform to which the grinding pad 100 is attached. Then, the selected dressing surface (in Figure 3 The dressing surface 22c is in sliding contact with the rotating polishing pad 100. Thus, the polishing pad 100 can be dressed with a certain pressing pressure, and the polishing pad 100 can be dressed more uniformly.

[0048] in addition, Figure 3 The pad dresser 2 shown has four dressing surfaces 22b-22e, but may also have two, three or five or more dressing surfaces. In addition, the curvature radius R1 of the dressing surfaces 22b-22e is not limited to the above value and can be appropriately set to match the surface shape of the polishing platform to which the polishing pad 100 is attached.

[0049] like Figure 4 and Figure 5 As shown, a pad dresser may be used instead of the pad dresser 2 , in which the base material of the grinding tool is made of a bendable metal and the curvature radius R1 of the dressing surface can be changed by pressing the grinding tool from the opposite side of the dressing surface.

[0050] Figure 4 Another example of a pad dresser that can be used in the present invention and that is configured such that the curvature radius of the dressing surface of the grinding tool can be changed is shown. Figure 4 Only the structure near the abrasive tool of the pad dresser is shown.

[0051] Figure 4 The pad dresser 3 shown includes an arm 31 (not shown) and a grinder 32. The grinder 32 is fixed to a holder 34 by two fixing members 33, and the holder 34 is fixed to an end 31a (not shown) of the arm 31. In addition, the pad dresser 3 includes a pressing member 35, and is configured so that the curvature radius R1 of the dressing surface 32b can be changed by pressing a part of the grinder 32 on the opposite side of the dressing surface 32b with the pressing member 35.

[0052] The bendable metal constituting the base material 32 a of the grinding wheel 32 is not particularly limited as long as it can be bent by the pressing member 35 , and SUS, titanium, aluminum, a superelastic alloy, or the like can be used.

[0053] Figure 4 The pad dresser 3 shown in the figure can make the grinding tool 32 as shown in the figure become larger by increasing the force of pressing the grinding tool 32 by the pressing member 35. Figure 4 The dotted line in the figure indicates that the curvature radius R1 of the dressing surface 32b is reduced by deformation. In this way, by changing the curvature radius R1 of the dressing surface 32b to match the surface shape of the grinding platform and making the grinding tool 32 slide in contact with the rotating grinding pad 100, the grinding pad 100 can be dressed with a certain pushing pressure and the grinding pad 100 can be dressed more evenly.

[0054] Figure 5Another example of a pad dresser that can be used in the present invention and that is configured such that the curvature radius of the dressing surface of the grinding tool can be changed is shown. Figure 5 Only the structure near the abrasive tool of the pad dresser is shown.

[0055] Figure 5 The pad dresser 4 shown includes an arm 41 (not shown) and a grinder 42. The grinder 42 is fixed to a holder 44 having a thermal expansion coefficient different from that of a base material 42a by a fixing member 43, and is attached to an end 41a (not shown) of the arm 41 via the holder 44. In addition, a flow path 44a through which a liquid W flows is provided inside the holder 44.

[0056] Liquid W of a predetermined temperature, such as water, is introduced into the flow path 44a of the holder 44 thus constructed and circulated, so that the temperature of the grinding tool 42 and the holder 44 is changed. Then, the grinding tool 42 is deformed due to the difference in thermal expansion coefficients between the two, thereby changing the radius of curvature R1 of the dressing surface 42b. In this way, by changing the radius of curvature R1 of the grinding tool 42 to match the surface shape of the grinding platform and making the grinding tool 42 slide in contact with the rotating grinding pad 100, the grinding pad 100 can be dressed with a certain pressing pressure and the grinding pad 100 can be dressed more uniformly.

[0057] As materials constituting the base material 42a of the grinding tool 42 and the retainer 44, metals having different thermal expansion coefficients can be used. For example, the base material 42a of the grinding tool 42 can be made of SUS, titanium, aluminum, a low thermal expansion alloy (Invar), etc. In addition, the retainer 44 can be made of SUS, titanium, aluminum, etc. Specifically, the base material 42a of the grinding tool 42 can be made of a low thermal expansion alloy (Invar), and the retainer 44 can be made of SUS, but it is not limited thereto.

[0058] When the thermal expansion coefficient of the holder 44 is made larger than the thermal expansion coefficient of the base material 42a of the mold 42, for example, low-temperature water is circulated as the liquid W in the flow path 44a of the holder 44. As a result, the holder 44 contracts, and the curvature radius R1 of the trimmed surface 42b of the mold 42 can be changed. On the other hand, when the thermal expansion coefficient of the holder 44 is made smaller than the thermal expansion coefficient of the base material 42a of the mold 42, for example, high-temperature water is circulated as the liquid W in the flow path 44a of the holder 44. As a result, the base material 42a of the mold 42 expands, and the curvature radius R1 of the trimmed surface 42b of the mold 42 can be changed.

[0059] Figure 6 Still another example of a pad dresser that can be used in the present invention and that is configured such that the curvature radius of the dressing surface of the grinding tool can be changed is shown. Figure 6 Only the structure near the abrasive tool of the pad dresser is shown.

[0060] Figure 6 The pad dresser 5 shown includes an arm 51 (not shown) and a plurality of grinding wheels 52. Each grinding wheel 52 is fixed to the lower surface of a cylinder 53, and the upper surface of the cylinder 53 is fixed to a holder 54. The holder 54 is fixed to an end 51a (not shown) of the arm 51.

[0061] In the pad dresser 5, the lower surfaces of the plurality of grinding tools 52 form a dressing surface as a whole, and the curvature radius R1 of the dressing surface can be changed by changing the extension and contraction degree of each cylinder 53. In addition, the curvature radius R1 of the dressing surface can be obtained by fitting the contour of the surface formed by the lower surfaces of all the grinding tools 52 with an arc.

[0062] (Silicon Wafer Polishing Method)

[0063] The method for polishing a silicon wafer according to the present invention is characterized in that the silicon wafer is polished using a polishing pad that has been dressed using the polishing pad dressing method according to the present invention.

[0064] As described above, in the dressing method of the polishing pad according to the present invention, a pad dresser is used in which the curvature radius R1 of the dressing surface of the grinding tool that is in sliding contact with the polishing pad in the radial direction of the polishing platform can be changed, so the polishing pad can be more uniformly dressed even when the surface of the rotating platform is curved. As a result, by grinding the silicon wafer using the dressed polishing pad, the flatness of the silicon wafer can be improved.

[0065] (Method for manufacturing silicon wafer)

[0066] The method for manufacturing a silicon wafer according to the present invention is characterized in that a silicon wafer obtained by performing wafer processing on a single crystal silicon ingot grown by a predetermined method is polished using the above-mentioned method for polishing a silicon wafer according to the present invention.

[0067] As described above, the flatness of the silicon wafer can be improved by the method for polishing a silicon wafer according to the present invention. Therefore, a silicon wafer obtained by performing wafer processing on a single crystal silicon ingot grown by a predetermined method such as a Czochralski (CZ) method or a floating zone melting (FZ) method can be polished using the method for polishing a silicon wafer according to the present invention, thereby manufacturing a silicon wafer with higher flatness.

[0068] (Silicon wafer polishing device)

[0069] The polishing device for silicon wafer according to the present invention is a polishing device comprising a polishing platform, a polishing pad attached to the polishing platform, and a pad dresser with a grinding tool attached thereto for dressing the polishing pad. Here, the device is characterized in that the curvature radius R1 of the dressing surface of the grinding tool in sliding contact with the polishing pad in the radial direction of the polishing platform can be changed.

[0070] The polishing device of the silicon wafer according to the present invention is characterized in that it is provided with a pad dresser, and the pad dresser can be used in the dressing method of the polishing pad according to the present invention. By providing the polishing device with the pad dresser, the polishing pad can be dressed with a certain pushing pressure to dress the polishing pad more uniformly. As a result, by polishing the silicon wafer using the dressed polishing pad, the flatness of the silicon wafer can be improved.

[0071] Pad conditioner such as Figure 3 As shown, the pad dresser 2 can be configured such that the grinding wheel 22 has a plurality of dressing surfaces 22 b to 22 e having different curvature radii, and the curvature radius R1 of the dressing surface in sliding contact with the polishing pad 100 can be changed by rotating the grinding wheel 22 .

[0072] Furthermore, the pad dresser may be a pad dresser in which the base material of the grinding tool is made of a flexible alloy and the curvature radius R1 of the dressing surface can be changed by pressing the grinding tool from the opposite side to the dressing surface.

[0073] Specifically, if Figure 4 As shown, the following pad dresser can be made: the grinding tool 32 is attached to the pad dresser 3 via the retaining member 34, and both ends of the base material 32a of the grinding tool 32 are connected to the retaining member 34. By using a pushing member 35 to push a part of the grinding tool 32 on the opposite side of the dressing surface 32b, the curvature radius R1 of the dressing surface 32b can be changed.

[0074] Or, if Figure 5 As shown, the following pad conditioner 4 can be made: the grinding tool 42 is attached to the pad conditioner 4 via a holder 44 having a thermal expansion coefficient different from that of the base material 42a of the grinding tool 42, and the curvature radius R1 of the dressing surface 42b can be changed by changing the temperature of the holder 44.

[0075] Furthermore, the pad conditioner is Figure 6 As shown, the following pad dresser 5 can be made: it has an arm 51 (not shown) and a plurality of grinding tools 52, each grinding tool 52 is fixed to the lower surface of the cylinder 53, and the upper surface of the cylinder 53 is fixed to the retaining member 54. By changing the degree of extension and contraction of each cylinder 53, the curvature radius R1 of the dressing surface can be changed.

[0076] Industrial Applicability

[0077] According to the present invention, even when the surface of the rotating table is curved, the polishing pad can be dressed more uniformly, and thus the present invention is useful in the semiconductor wafer manufacturing industry.

[0078] Description of Reference Numerals

[0079] 1, 2, 3, 4, 5 pad dressers

[0080] 11, 21, 31, 41, 51 arms

[0081] 11a, 31a, 41a, 51a ends

[0082] 12, 22, 32, 42, 52 grinding tools

[0083] 12a, 22a, 32a, 42a substrate

[0084] 12b, 22b, 22c, 22d, 22e, 32b, 42b finishing surface

[0085] 13, 34, 44, 54 retaining parts

[0086] 23 Rotation axis

[0087] 24, 53 cylinders

[0088] 33, 43 fixings

[0089] 35 Pushing parts

[0090] 44a flow path

[0091] 100 polishing pad

[0092] R1, R2 radius of curvature

[0093] WLiquid

Claims

1. A method for dressing a polishing pad, comprising: pushing a polishing tool of a pad dresser with a polishing tool against a polishing pad attached to a polishing platform so that the polishing tool and the polishing pad are in sliding contact, thereby dressing the polishing pad, characterized in that: A pad dresser is used in which a curvature radius R1 of a dressing surface of the grinding tool that is in sliding contact with the polishing pad in a radial direction of the polishing platen can be changed.

2. The method for dressing a polishing pad according to claim 1, wherein: The curvature radius R1 of the dressing surface of the grinding tool is changed to be smaller than the curvature radius R2 of the surface of the polishing pad, and then the polishing pad is dressed.

3. The method for dressing a polishing pad according to claim 1 or 2, wherein: A pad conditioner is used in which the grinding wheel has a plurality of dressing surfaces having different curvature radii, and the curvature radius R2 of the dressing surface in sliding contact with the polishing pad can be changed by rotating the grinding wheel.

4. The method for dressing a polishing pad according to claim 1 or 2, wherein: A pad dresser is used in which the base material of the grinding tool is made of a flexible alloy and the curvature radius R1 of the dressing surface can be changed by pressing the grinding tool from the side opposite to the dressing surface.

5. The method for dressing a polishing pad according to claim 4, wherein: The following pad dresser is used: the aforementioned grinding tool is attached to the aforementioned pad dresser via a retaining member, both ends of the base material of the aforementioned grinding tool are connected to the retaining member, and the aforementioned curvature radius R1 of the aforementioned dressing surface can be changed by pushing a part of the aforementioned grinding tool on the opposite side of the aforementioned dressing surface with a pushing member.

6. The method for dressing a polishing pad according to claim 4, wherein: A pad conditioner is used in which the grinding tool is attached to the pad conditioner via a holder having a thermal expansion coefficient different from that of a base material of the grinding tool, and the curvature radius R1 of the dressing surface can be changed by changing the temperature of the holder.

7. A method for grinding a silicon wafer, characterized in that: A silicon wafer is polished using a polishing pad which has been dressed using the polishing pad dressing method according to claim 1 or 2.

8. A method for manufacturing a silicon wafer, characterized in that: The silicon wafer is polished using the silicon wafer polishing method according to claim 7, wherein the silicon wafer is obtained by performing a wafer processing on a single crystal silicon ingot grown by a predetermined method.

9. A silicon wafer polishing device comprising a polishing platform, a polishing pad attached to the polishing platform, and a pad dresser with a grinding tool attached thereto for dressing the polishing pad, wherein: The dressing surface of the grinding tool that comes into sliding contact with the polishing pad is configured such that a curvature radius R1 in a radial direction of the polishing platen can be changed.

10. The silicon wafer polishing device according to claim 9, wherein: The grinding wheel has a plurality of dressing surfaces having different curvature radii, and is configured such that a curvature radius R1 of the dressing surface that comes into sliding contact with the polishing pad can be changed by rotating the grinding wheel.

11. The silicon wafer polishing device according to claim 10, wherein: The base material of the grinding wheel is made of a flexible alloy, and is configured so that the curvature radius R1 of the dressing surface can be changed by pressing the grinding wheel from the opposite side to the dressing surface.

12. The silicon wafer polishing device according to claim 11, wherein: The grinding tool is attached to the pad dresser via a retaining member, and both ends of the base material of the grinding tool are connected to the retaining member, so that the curvature radius R1 of the dressing surface can be changed by pressing a part of the grinding tool on the opposite side of the dressing surface with a pressing member.

13. The silicon wafer polishing device according to claim 11, wherein: The grinding wheel is attached to the pad conditioner via a holder having a thermal expansion coefficient different from that of a base material of the grinding wheel, and is configured so that the curvature radius R1 of the dressing surface can be changed by changing the temperature of the holder.

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