Wafer polishing device, polishing pad, and wafer polishing method

Abstract

To provide a single-wafer type wafer polishing device capable of rapidly and favorably polishing a surface to be polished of a wafer.SOLUTION: A wafer polishing device of the present invention includes: a surface plate 7 to which a polishing pad 1 having a polishing surface 1a is fixed, and which rotates the polishing surface 1a around a first axis O1; and a carrier 5 to which a single wafer W having a surface to be polished Wf is fixed, and which rotates the surface to be polished Wf around a second axis O2 parallel to the first axis O1. The surface to be polished Wf is polished by the polishing surface 1a under a predetermined surface pressure and in the presence of a polishing liquid 11a. The carrier 5 is swingable with respect to the second axis O2 such that the surface to be polished Wf follows the polishing surface 1a. The polishing pad 1 has a recess 10 in which the polishing surface 1a is recessed in a conical shape with the first axis O1 as a central axis, and contacts the surface to be polished Wf.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wafer polishing apparatus, a polishing pad, and a wafer polishing method. [Background technology]

[0002] Patent Document 1 discloses a wafer polishing apparatus. This wafer polishing apparatus includes a platen and a carrier. A polishing pad having a polishing surface is fixed to the platen, and the polishing surface is rotated about a first axis. A wafer having a surface to be polished is fixed to the carrier, and the carrier rotates the surface to be polished about a second axis parallel to the first axis. This wafer polishing apparatus polishes the surface to be polished with the polishing surface under a predetermined surface pressure and in the presence of a polishing liquid.

[0003] Wafer polishing apparatuses include batch-type apparatuses in which three to four wafers are fixed to one carrier and the polished surface of each wafer is polished by the polishing surface of a polishing pad, and single-wafer-type apparatuses in which a single wafer is fixed to one carrier and the polished surface of that wafer is polished by the polishing surface of a polishing pad. Some single-wafer-type wafer polishing apparatuses have a carrier that can swing about a second axis so that the polished surface conforms to the polishing surface. In the single-wafer-type wafer polishing apparatus disclosed in Patent Document 1, the carrier can swing about a second axis so that the polished surface conforms to the polishing surface.

[0004] Compared to batch polishing machines, single wafer polishing machines are becoming more commonly used when polishing the surfaces of large diameter wafers. Currently, for example, silicon carbide (SiC) wafers are mainly 6 inches in size, but there is a trend toward 8 inches, and it is expected that single wafer polishing machines will attract attention in the future. In single wafer polishing machines, if the carrier can oscillate around the second axis, it is said that the flatness of the wafer can be improved. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2004 / 28743 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the single-wafer wafer polishing apparatus described above, the number of wafers processed in one polishing run is inevitably smaller than in a batch-type wafer polishing apparatus, so it is not enough to simply be able to polish the surface to be polished well; higher-speed polishing is also required.

[0007] The present invention has been made in consideration of the above-described conventional situation, and has as its object to provide a single-wafer wafer polishing apparatus capable of polishing the polished surface of a wafer quickly and effectively. Another object of the present invention is to provide a polishing pad that, when used in such a single-wafer wafer polishing apparatus, can polish the polished surface of a wafer quickly and effectively. A further object of the present invention is to provide a wafer polishing method that can polish the polished surface of a wafer quickly and effectively in such a single-wafer wafer polishing apparatus. [Means for solving the problem]

[0008] The wafer polishing apparatus of the present invention comprises a platen on which a polishing pad having a polishing surface is fixed and which rotates the polishing surface about a first axis, and a carrier on which a single wafer having a surface to be polished is fixed and which rotates the surface to be polished about a second axis parallel to the first axis, and which polishes the surface to be polished with the polishing surface under a predetermined surface pressure and in the presence of a polishing liquid, the carrier is swingable about the second axis so that the surface to be polished follows the polishing surface; The polishing pad is characterized in that the polishing surface has a recess that is conically recessed with the first axis as a central axis and comes into contact with the surface to be polished.

[0009] The polishing pad of the present invention is a polishing pad used for polishing wafers in a wafer polishing apparatus, The wafer polishing apparatus includes a surface plate to which the polishing pad having a polishing surface is fixed and which rotates the polishing surface around a first axis, and a carrier to which a single wafer having a surface to be polished is fixed and which rotates the surface to be polished around a second axis parallel to the first axis, and polishes the surface to be polished with the polishing surface under a predetermined surface pressure and in the presence of a polishing liquid, the carrier is swingable about the second axis so that the surface to be polished follows the polishing surface; The polishing surface has a recess that is conically recessed with the first axis as a central axis and that abuts against the surface to be polished.

[0010] Furthermore, the wafer polishing method of the present invention includes a first preparation step of preparing a wafer polishing apparatus including a surface plate having a pad fixing surface and rotating the pad fixing surface about a first axis, and a carrier having a wafer fixing surface and rotating the wafer fixing surface about a second axis parallel to the first axis; a second preparation step of preparing a flat polishing pad and fixing the polishing pad to the pad fixing surface; a third preparation step of preparing a wafer having a surface to be polished and fixing a single wafer to the wafer fixing surface; a dressing step for forming a polishing surface on the polishing pad fixed to the pad fixing surface; a polishing step of polishing the surface to be polished with the polishing surface under a predetermined surface pressure and in the presence of a polishing liquid, In the dressing step, a recess is formed in the polishing surface so as to be recessed in a conical shape with the first axis as a central axis and come into contact with the surface to be polished, In the polishing step, the carrier is swung about the second axis so that the surface to be polished follows the polishing surface.

[0011] According to the inventors' test results, in a single-wafer wafer polishing machine in which the carrier can oscillate about the second axis and the wafer's polished surface conforms to the polishing surface of the polishing pad, using a polishing pad with a conical recess whose polishing surface is centered on the first axis results in a flat and large wafer removal rate even when polishing at high speed. This improves polishing efficiency in proportion to the rotation speed and pressure (Preston's Law). Furthermore, no scratches are generated on the polished surface after polishing, and the surface roughness is small.

[0012] On the other hand, even in a single-wafer wafer polishing machine in which the carrier can oscillate about the second axis and the wafer's polished surface conforms to the polishing surface of the polishing pad, if a polishing pad with a flat polishing surface or a polishing pad with a conical protrusion centered on the first axis is used, the wafer removal rate will be mountain-shaped and smaller than the above when polished at high speed. It is believed that this is because the platen or carrier rotates at high speed, causing the platen to thermally expand into a conical shape centered on the first axis, or the tape securing the polishing pad to the platen peels off, causing a conical rise centered on the first axis. Even in these cases, no scratches are produced on the polished surface after polishing, and the surface roughness is small.

[0013] The surface plate has a pad fixing surface on which a polishing pad is fixed. Before the polishing process, the pad fixing surface extends in a direction perpendicular to the first axis. The inventors have confirmed the effects of the present invention in a wafer polishing apparatus having this pad fixing surface.

[0014] The recess may have a straight generatrix or may have a center that curves and recesses away from the polished surface, but it is preferable that the center of the generatrix protrudes while curving toward the polished surface. If the center of the generatrix protrudes while curving toward the polished surface, the removal amount of the polished surface of the wafer after polishing is greater.

[0015] The polishing pad preferably comprises a resin matrix with a plurality of pores formed therein and abrasive particles held within the matrix or pores. This polishing pad is an abrasive-containing polishing pad, also known as an LHA (Loosely Held Abrasive) pad. Because a polishing liquid containing no abrasive particles can be used, even if the carrier employs a negative pressure fixing means, problems with the fixing means or the backside of the wafer are unlikely to occur. This allows for quick wafer removal and improves wafer polishing efficiency. Furthermore, when a polishing liquid containing abrasive particles is used, centrifugal force causes the abrasive particles to fly outward when the platen or carrier is rotated at high speed, making it difficult for the abrasive particles to reach the processing point. However, by using such an LHA pad, such problems are unlikely to occur due to the use of a polishing liquid containing no abrasive particles. [Effects of the Invention]

[0016] The wafer polishing apparatus of the present invention can polish the surface of a wafer quickly and effectively. Furthermore, the polishing pad of the present invention, when used in such a single-wafer-processing wafer polishing apparatus, can polish the surface of a wafer quickly and effectively. Furthermore, the wafer polishing method of the present invention can polish the surface of a wafer quickly and effectively in such a single-wafer-processing wafer polishing apparatus. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic cross-sectional view of a wafer polishing apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a graph showing the relationship between the radial length and thickness of the polishing pad in the wafer polishing apparatus and wafer polishing method of the embodiment. [Figure 3] FIG. 3 is a graph showing the relationship between the diameter length of a wafer after polishing and the removal amount under the first high-speed condition, in accordance with the wafer polishing apparatus and wafer polishing method of the embodiment. [Figure 4]FIG. 4 is a graph showing the relationship between the diameter length of a wafer after polishing and the removal rate under the second high-speed condition, in accordance with the wafer polishing apparatus and wafer polishing method of the embodiment. [Figure 5] FIG. 5 is a graph showing the surface roughness of a wafer after polishing, relating to the wafer polishing apparatus and wafer polishing method of the embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view of the wafer polishing apparatus of Comparative Example 1. As shown in FIG. [Figure 7] FIG. 7 is a graph showing the relationship between the radial length and thickness of the polishing pad in the wafer polishing apparatus and wafer polishing method of Comparative Example 1. [Figure 8] FIG. 8 is a graph showing the relationship between the diameter length of a wafer after polishing and the removal amount under the first high-speed condition, in the wafer polishing apparatus and wafer polishing method of Comparative Example 1. [Figure 9] FIG. 9 is a graph showing the relationship between the diameter length of the wafer after polishing and the removal rate under the second high-speed condition, in accordance with the wafer polishing apparatus and wafer polishing method of Comparative Example 1. [Figure 10] FIG. 10 is a schematic cross-sectional view of the wafer polishing apparatus of Comparative Example 2. As shown in FIG. [Figure 11] FIG. 11 is a graph showing the relationship between the radial length and thickness of the polishing pad in the wafer polishing apparatus and wafer polishing method of Comparative Example 2. [Figure 12] FIG. 12 is a graph showing the relationship between the diameter length of a wafer after polishing and the removal amount under the first high-speed condition, in the wafer polishing apparatus and wafer polishing method of Comparative Example 2. [Figure 13] FIG. 13 is a graph showing the relationship between the diameter length of the wafer after polishing and the removal amount under the second high-speed condition, in the wafer polishing apparatus and wafer polishing method of Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, examples embodying the present invention will be described together with comparative examples 1 and 2 with reference to the drawings.

[0019] (Example) <First preparation process> First, a single-wafer wafer polishing apparatus was prepared. This wafer polishing apparatus is a modified version of the LAPMASTER LAPOLISH15. As shown in Figure 1, this wafer polishing apparatus is equipped with a surface plate 7, a single carrier 5, a drive unit 9, and a polishing liquid supply unit 11.

[0020] The surface plate 7 is a horizontal disk-shaped plate that contains the carrier 5 within its own radius. The diameter of the surface plate 7 is 380 inches. A first rotating shaft 7a is vertically mounted on the underside of the surface plate 7. The first rotating shaft 7a is driven to rotate at a predetermined speed around a first axis O1. The upper surface of the surface plate 7 serves as a pad fixing surface 7b. Before the polishing process, the pad fixing surface 7b extends in a direction perpendicular to the first axis O1.

[0021] The carrier 5 has a horizontal disk shape. A wafer fixing surface 5a is recessed on the lower surface of the carrier 5, and the wafer W is fixed to the wafer fixing surface 5a by negative pressure. A second rotation shaft 5b is vertically provided on the upper surface of the carrier 5. The second rotation shaft 5b is driven to rotate at a predetermined speed around a second axis O2. The carrier 5 is configured to be swingable about the second axis O2 by a constant velocity joint or the like.

[0022] The drive unit 9 includes a main drive unit 9a, a sub-drive unit 9b, and a pressure unit 9c. The main drive unit 9a drives the first rotating shaft 7a to rotate around the first axis O1 at a predetermined speed. The sub-drive unit 9b drives the second rotating shaft 5b to rotate around the second axis O2 at a predetermined speed. The pressure unit 9c presses the second rotating shaft 5b and the sub-drive unit 9b toward the surface plate 7 with a predetermined load.

[0023] The polishing liquid supply device 11 is provided above the surface plate 7. The polishing liquid supply device 11 provides a polishing liquid 11a between each wafer W and the polishing pad 1. The polishing liquid is a potassium permanganate-based aqueous solution and does not contain abrasive particles.

[0024] <Second preparation process> A flat polishing pad called an LHA pad was prepared. This polishing pad is made of a base resin with multiple pores formed in the base material, and abrasive particles are held in the base material or the pores. The base resin is polyethersulfone, and the abrasive particles are silica. The volume percentages of the base material, pores, and abrasive particles are 28 volume%, 46 volume%, and 26 volume%, respectively. The average particle size of the abrasive particles is 200 nm.

[0025] <3rd preparation process> A 4-inch wafer W made of SiC was prepared, and a single wafer W was fixed on the wafer fixing surface 5a. At this time, the Si surface was used as the surface to be polished Wf.

[0026] <Dressing process> The polishing pad was fixed to the pad fixing surface 7b of the surface plate 7 with tape (not shown). Then, a dressing tool (not shown) was prepared and a recess 10 was formed in the polishing pad with the dressing tool. Figure 1 shows the polishing pad 1 with the recess 10 formed therein. The recess 10 consists of a flat bottom surface 10a with the first axis O1 as its central axis, and a conical surface 10b that is continuous with the bottom surface 10a and is recessed in a conical shape with the first axis O1 as its central axis. The polishing surface 1a of the polishing pad 1 consists of the bottom surface 10a and the conical surface 10b.

[0027] The polished surface Wf of the wafer W is positioned so as to abut on the conical surface 10b, not on the bottom surface 10a. The relationship between the radial length (mm) and thickness (μm) of the polishing pad 1 is shown in Figure 2. As shown in Figure 2, the generatrix L of the conical surface 10b is an approximately straight line.

[0028] <Polishing process> The surface to be polished Wf was polished by the polishing surface 1a under the following first and second high-speed conditions. During this polishing, the carrier 5 was oscillated about the second axis O2 so that the surface to be polished Wf followed the conical surface 10b of the polishing surface 1a.

[0029] First high-speed condition: The surface to be polished Wf was polished by the polishing surface 1a at a surface pressure of 40 kPa and a polishing solution of pH 7 at a rate of 10 mL / min, with the rotation speed of the platen 7 and the carrier 5 set to 60 rpm. The polishing time was 1 hour.

[0030] Second high-speed conditions: The surface to be polished Wf was polished by the polishing surface 1a at a surface pressure of 70 kPa and a polishing liquid flow rate of 10 mL / min, with the rotation speed of the platen 7 and the carrier 5 set to 120 rpm. The polishing time was 1 hour.

[0031] Figure 3 shows the relationship between the diameter length (mm) of the wafer W after polishing under the first high-speed conditions and the removal rate (μm) of the polished surface Wf. The temperature of the platen 7 during polishing under the first high-speed conditions was 36.3°C. The removal rate under the first high-speed conditions was 1098 nm / hour. A Keyence SI-T1000V spectroscopic interferometer was used to measure the thickness.

[0032] The relationship between the diameter length (mm) of the wafer W after polishing under the second high-speed conditions and the removal rate (μm) of the polished surface Wf is shown in Figure 4. The temperature of the platen 7 during polishing under the second high-speed conditions was 54.0°C. The polishing rate under the second high-speed conditions was 8139 nm / hour.

[0033] Additionally, a polishing pad 1 with a circular groove formed concentric with the first axis O1 was used, and the polished surface Wf was polished with the polishing surface 1a in the presence of a polishing solution of pH 3. Other conditions were the same as those for the second high-speed conditions. After polishing, the presence or absence of scratches and the surface roughness Ra (nm) were measured at nine locations on the polished surface Wf of the wafer W. The presence or absence of scratches was determined using a Lasertec OPTELICS HYBRID spectral interferometric displacement measuring instrument. The surface roughness was measured using a Hitachi High-Tech VS1330 white light interferometric microscope. The results, along with the average values, are shown in Figure 5.

[0034] 3 and 4, the results of the temperature of the platen 7 during polishing and the polishing rate show that with the wafer polishing apparatus of the embodiment, the removal amount of the wafer W is flat and large, even when polishing at high speed. It also shows that no scratches occur on the polished surface Wf after polishing, and the surface roughness is small as shown in FIG. 5. This is because the embodiment uses a polishing pad 1 whose polishing surface 1a has a conical recess 10 with the first axis O1 as its central axis.

[0035] (Comparative Example 1) Similar to Example 1, the first to third preparation steps were carried out. Then, in the dressing step, a flat polishing surface 2a was formed on the polishing pad using a dressing tool. FIG. 6 shows the polishing pad 2 on which the polishing surface 2a was formed. FIG. 7 shows the relationship between the radial length (mm) and thickness dimension (μm) of the polishing pad 2. As shown in FIG. 7, the generatrix L of the polishing surface 2a is also approximately straight.

[0036] In the polishing step, the surface to be polished Wf was polished by the polishing surface 2a under the first and second high-speed conditions.

[0037] The relationship between the diameter length (mm) of the wafer W after polishing under the first high-speed conditions and the removal rate (μm) of the polished surface Wf is shown in Figure 8. The temperature of the platen 7 during polishing under the first high-speed conditions was 36.8°C. The polishing rate under the first high-speed conditions was 1644 nm / hour.

[0038] The relationship between the diameter length (mm) of the wafer W after polishing under the second high-speed conditions and the removal rate (μm) of the polished surface Wf is shown in Figure 9. The temperature of the platen 7 during polishing under the second high-speed conditions was 51.0°C. The polishing rate under the second high-speed conditions was 7007 nm / hour.

[0039] 8 and 9, which show the temperature of the platen 7 during polishing and the polishing rate, the wafer polishing apparatus of Comparative Example 1 polishes at high speed, resulting in a mountain-shaped removal amount for the wafer W, which is smaller than that of the Examples. This is because the polishing pad 2 with a flat polishing surface 2a is used. In Comparative Example 1, no scratches were generated on the polished surface Wf after polishing, and the surface roughness was small. (Comparative Example 2) Similar to Example 1 and Comparative Example 1, the first to third preparation steps were carried out. Then, in the dressing step, convex portions 20 were formed on the polishing pad using a dressing tool. FIG. 10 shows a polishing pad 3 on which convex portions 20 have been formed. The convex portions 20 consist of a flat upper surface 20a whose central axis is the first axis O1, and a conical surface 20b that is continuous with the upper surface 20a and protrudes in a conical shape whose central axis is the first axis O1. The polishing surface 3a of the polishing pad 3 consists of the upper surface 20a and the conical surface 20b.

[0040] 11 shows the relationship between the radial length (mm) and the thickness (μm) of polishing pad 3. As shown in Fig. 11, the generatrix L of polishing surface 3a is also approximately straight.

[0041] In the polishing step, the surface to be polished Wf was polished by the polishing surface 3a under the first and second high-speed conditions.

[0042] The relationship between the diameter length (mm) of the wafer W after polishing under the first high-speed conditions and the removal rate (μm) of the polished surface Wf is shown in Figure 12. The temperature of the platen 7 during polishing under the first high-speed conditions was 36.1°C. The polishing rate under the first high-speed conditions was 1308 nm / hour.

[0043] The relationship between the diameter length (mm) of the wafer W after polishing under the second high-speed conditions and the removal rate (μm) of the polished surface Wf is shown in Figure 13. The temperature of the platen 7 during polishing under the second high-speed conditions was 59.0°C. The polishing rate under the second high-speed conditions was 7460 nm / hour.

[0044] 12 and 13, which show the temperature of the platen 7 during polishing and the polishing rate, the wafer polishing apparatus of Comparative Example 2 also polishes at high speed, resulting in a mountain-shaped removal amount for the wafer W, which is smaller than that of the Examples. This is because the polishing pad 3 used has a polishing surface 3a with a conical protrusion 20 whose central axis is the first axis O1. Also in Comparative Example 2, no scratches were generated on the polished surface Wf after polishing, and the surface roughness was small.

[0045] Therefore, the wafer polishing apparatus of the embodiment can quickly and effectively polish the polishing surface Wf of the wafer W. Furthermore, the wafer polishing method of the embodiment can quickly and effectively polish the polishing surface Wf of the wafer W in such a single-wafer type wafer polishing apparatus.

[0046] In the above embodiment, recesses 10 are formed in the polishing surface of the polishing pad in the dressing process, but it is also possible to manufacture a polishing pad 1 with recesses 10 formed in advance and attach the polishing pad to the pad fixing surface 7b of the surface plate 7. In this case, when the polishing pad 1 is used in the single-wafer type wafer polishing apparatus described above, it is possible to polish the polished surface Wf of the wafer W quickly and effectively.

[0047] Furthermore, because the wafer polishing apparatus of the present embodiment employs an abrasive-containing polishing pad, also known as an LHA pad, it is possible to employ a polishing liquid 11a that does not contain abrasive particles. Therefore, even if the carrier 5 employs a fixing means that uses negative pressure, problems are unlikely to occur with the fixing means or the backside of the wafer W. This allows for quick detachment of the wafer W, improving the polishing efficiency of the wafer W. Furthermore, the frequency of maintenance, such as part replacement, of the wafer polishing apparatus is reduced.

[0048] The inventors conducted various studies to determine the angle θ at which the recess 10 is recessed from a parallel plane parallel to the pad fixing surface 7b and the preferred depth from the parallel plane to the bottom surface 10a in an actual wafer polishing apparatus of the embodiment shown in Figure 1.

[0049] As a result, in an actual machine with a 380-inch diameter surface plate 7, it was found that the angle θ was preferably 0.009 to 0.015° and the depth from the parallel surface to the bottom surface 10a was 40±10 μm. On the other hand, in an actual machine with a 610-inch diameter surface plate 7, it was found that the angle θ was preferably 0.009 to 0.013° and the depth from the parallel surface to the bottom surface 10a was preferably 60±10 μm. From these results, it is inferred that, in commercially available actual machines, a polishing pad 1 having a polishing surface 1a with recesses 10 recessed at an angle θ of 0.01 to 0.015 is preferable.

[0050] Although the present invention has been described above with reference to the examples, it goes without saying that the present invention is not limited to the above examples and can be modified and applied as appropriate within the scope of the invention.

[0051] For example, although the wafer polishing apparatus in FIG. 1 has a single carrier 5, a wafer polishing apparatus to which the present invention can be applied may have a plurality of carriers 5 facing the conical surface 10b. [Industrial Applicability]

[0052] The present invention can be used in semiconductor device manufacturing equipment. [Explanation of symbols]

[0053] 1a…Polished surface 1...Polishing pad O1…1st axis center 7...Surface plate Wf…Surface to be polished W...wafer O2…2nd axis center 5...Carrier 11a...polishing liquid 10...recess 7b...Pad fixing surface 5a...wafer fixing surface

Claims

1. A wafer polishing apparatus comprising: a platen on which a polishing pad having a polishing surface is fixed and which rotates the polishing surface about a first axis; and a carrier on which a single wafer having a surface to be polished is fixed and which rotates the surface to be polished about a second axis parallel to the first axis; and wherein the surface to be polished is polished by the polishing surface under a predetermined surface pressure in the presence of a polishing liquid, the carrier is swingable about the second axis so that the surface to be polished follows the polishing surface; The polishing pad has a recess in the polishing surface that is conically recessed about the first axis and that abuts against the surface to be polished.

2. In a polishing pad used for polishing wafers in a wafer polishing device, The wafer polishing apparatus includes a surface plate to which the polishing pad having a polishing surface is fixed and which rotates the polishing surface around a first axis, and a carrier to which a single wafer having a surface to be polished is fixed and which rotates the surface to be polished around a second axis parallel to the first axis, and polishes the surface to be polished with the polishing surface under a predetermined surface pressure in the presence of a polishing liquid, the carrier is swingable about the second axis so that the surface to be polished follows the polishing surface; The polishing pad according to claim 1, wherein the polishing surface has a recessed portion that is conically recessed about the first axis and that abuts against the surface to be polished.

3. a first preparation step of preparing a wafer polishing apparatus including a surface plate having a pad fixing surface and rotating the pad fixing surface around a first axis, and a carrier having a wafer fixing surface and rotating the wafer fixing surface around a second axis parallel to the first axis; a second preparation step of preparing a flat polishing pad and fixing the polishing pad to the pad fixing surface; a third preparation step of preparing a wafer having a surface to be polished and fixing a single wafer to the wafer fixing surface; a dressing step for forming a polishing surface on the polishing pad fixed to the pad fixing surface; a polishing step of polishing the surface to be polished with the polishing surface under a predetermined surface pressure in the presence of a polishing liquid, In the dressing step, a recess is formed in the polishing surface so as to be recessed in a conical shape with the first axis as a central axis and come into contact with the surface to be polished, a polishing step of oscillating the carrier about the second axis so that the surface to be polished follows the polishing surface;

4. the surface plate has a pad fixing surface to which the polishing pad is fixed, 4. The wafer polishing method according to claim 3, wherein the pad fixing surface before the polishing step extends in a direction perpendicular to the first axis.

5. 5. The wafer polishing method according to claim 3, wherein the polishing pad comprises a base material made of a resin and having a plurality of pores formed therein, and abrasive particles held in the base material or in the pores.

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