Surface processing method

Abstract

To further enhance cost-effectiveness of recovering and reusing used slurry.SOLUTION: A surface processing method includes: planarizing a processing surface (W1), which is a surface of a workpiece (W) through chemical and mechanical actions by moving the workpiece and a processing pad (3) relative to each other while slurry (S) containing at least abrasive grains is interposed between the processing surface and the processing pad. During the planarization process, the slurry circulates through a circulation flow channel (R), which includes a slurry supply flow channel (63) for supplying the slurry to the processing pad and a recovery flow channel (652) for recovering the slurry after use. In cleaning the processing pad with a cleaning solution (L), the cleaning solution is discharged through a waste liquid flow channel (653), which is separate from the circulation flow channel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a surface processing method for planarizing a surface to be processed, which is the surface of a workpiece, by chemical and mechanical action. [Background technology]

[0002] Patent Document 1 discloses a method for recovering abrasives from recovered slurry containing used abrasives in CMP, a process in which polishing is performed with an abrasive slurry interposed between a polishing member such as a polishing pad and an object to be polished. CMP is an abbreviation for Chemical Mechanical Polishing.

[0003] Specifically, the recovery method described in Patent Document 1 is a method for recovering an abrasive from an abrasive slurry obtained by polishing an object containing silicon as its main component, and involves removing the object components and recovering the abrasive through at least the following steps 1 to 3 under conditions in which a pH adjuster is not used. Step 1: Adding a solvent to the abrasive slurry Step 2: Dissolving particles of the object to be polished contained in the abrasive slurry Step 3: Filtering the abrasive slurry to recover the abrasive [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-175138 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, previous attempts to recover and reuse used slurry required complex processes such as adding solvents or chemicals to dissolve or separate the polished object. Therefore, although it is possible to reduce costs compared to disposing of used slurry without recovering or reusing it, there is still room for cost improvement.

[0006] The present disclosure has been made in consideration of the circumstances exemplified above, etc. That is, the present disclosure provides, for example, a technique that enables further improvement in the cost improvement effect by recovering and reusing used slurry. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a surface processing method for planarizing a work surface (W1) that is a surface of a workpiece (W) by chemical and mechanical action by relatively moving the workpiece and a processing pad (3) while interposing a slurry (S) containing at least abrasive grains between the workpiece and the processing pad (3) includes the following processes, procedures, or steps: During the planarization process, the slurry is circulated through a slurry circulation flow path (R) including a slurry supply flow path (63) for supplying the slurry to the processing pad and a recovery flow path (652) for recovering the used slurry; When the processing pad is washed with a cleaning liquid (L), the cleaning liquid is discharged through a waste liquid flow path (653) that is separate from the circulation flow path.

[0008] In addition, in each section of the application documents, each element may be assigned a reference symbol in parentheses. In this case, the reference symbol merely indicates an example of the correspondence between the element and the specific configuration described in the embodiment described below. Therefore, the present disclosure is not limited in any way by the description of the reference symbol. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a schematic configuration diagram of a surface processing apparatus for carrying out a surface processing method according to an embodiment of the present disclosure. [Figure 2] 1 is a graph showing the degree of decrease in processing rate in the surface processing methods according to the examples and the comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Embodiment) Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The following embodiments, their modifications, and the accompanying drawings are schematic or simplified for the purpose of concisely explaining the contents of the present disclosure, and are not intended to limit the contents of the present disclosure in any way. Therefore, it goes without saying that the descriptions in the drawings do not necessarily coincide with the specific device configurations that are actually manufactured and sold. In other words, unless expressly limited by the applicant in the prosecution history of this application, it goes without saying that the present disclosure should not be interpreted as being limited by the descriptions in the drawings and the corresponding device configurations, functions, or operations described below.

[0011] (Surface processing equipment) Referring to FIG. 1, a surface processing apparatus 1 is configured to planarize a workpiece surface W1, which is the surface of a workpiece W, by chemical and mechanical action. "Planarization" includes polishing and grinding. Known methods of this type of planarization include CMP, ECMP, and ECMG. ECMP stands for Electro-Chemical Mechanical Polishing. ECMG stands for Electro-Chemical Mechanical Grinding. CMP can also be interpreted as a comprehensive concept that includes ECMP. In other words, CMP in the broad sense includes ECMP unless explicitly stated to be CMP in the narrow sense that does not include ECMP.

[0012] In this embodiment, the surface processing apparatus 1 has a configuration as a CMP apparatus or an ECMP apparatus for polishing a workpiece W, which is a single crystal SiC wafer. Specifically, the surface processing apparatus 1 includes a workpiece support unit 2, a processing pad 3, a pad support unit 4, a casing 5, a slurry circulating supply mechanism 6, a cleaning liquid supply unit 7, and a control unit 8. These elements that make up the surface processing apparatus 1 will be described in order below.

[0013] The workpiece support 2 is disposed opposite the processing pad 3. The workpiece support 2 is configured to rotate about a rotation axis 21 while pressing the workpiece W toward the processing pad 3, with the workpiece W held on the surface facing the processing pad 3 (i.e., the lower surface in the figure). The processing pad 3 may also be referred to as a "polishing pad," and may be made of a well-known material for CMP or ECMP, such as nonwoven fabric, polyurethane, or suede. The processing pad 3 is supported by a pad support 4. The workpiece support 2 and / or the pad support 4 are provided with an adjustment mechanism (not shown) for adjusting processing conditions. The processing conditions include, for example, temperature, pressing force, rotation speed, etc.

[0014] The casing 5 is provided to cover at least the processing position where the workpiece W and the processing pad 3 face each other, thereby preventing the slurry S supplied to the processing pad 3 or the processing position from scattering outside the device. The casing 5 is also configured to function as a tray or recovery container to receive the used slurry S used in the planarization processing at the processing position so that it does not leak outside the device. In this way, the surface processing device 1 is configured to planarize the processing surface W1 by chemical and mechanical action by moving the workpiece W and the processing pad 3 relative to each other while interposing the slurry S between the processing surface W1 and the processing pad 3.

[0015] The slurry circulating supply mechanism 6 is configured to supply the slurry S to the processing pad 3 or the processing position, and to collect the used slurry S and reuse it for planarization processing. Specifically, the slurry circulating supply mechanism 6 includes a slurry tank 61, an agitator 62, a slurry supply flow path 63, a supply pump 64, a slurry discharge flow path 65, a waste liquid container 66, and a three-way valve 67.

[0016] The slurry tank 61 is provided to store a predetermined amount of slurry S to be supplied to the processing pad 3 or the processing position. The slurry S contains at least abrasive grains. That is, the slurry S contains a solvent, abrasive grains, and an agent for chemical action (e.g., an oxidizing agent, an electrolyte, etc.). The chemical action includes an electrochemical action. The agitator 62 is configured to agitate the slurry S using a rotating agitator 621 inside the slurry tank 61, thereby suppressing the settling of the abrasive grains in the slurry S and maintaining a good dispersion state of the abrasive grains.

[0017] The slurry supply passage 63 is configured to supply the slurry S from the slurry tank 61 to the processing pad 3. Specifically, the base end of the slurry supply passage 63 is located inside the slurry tank 61, and the tip end, a slurry ejection port 631, is provided to eject the slurry S toward the processing pad 3. A supply pump 64 is interposed in the slurry supply passage 63 to pump the slurry S toward the slurry ejection port 631.

[0018] The slurry discharge flow path 65 is provided to discharge, from the casing 5, the used slurry S received in the casing 5 and the cleaning liquid L used to clean the processing pad 3. For example, pure water can be used as the cleaning liquid L. Specifically, the slurry discharge flow path 65 has a primary discharge flow path 651, a recovery flow path 652, and a waste liquid flow path 653. The slurry discharge flow path 65 is configured so that the primary discharge flow path 651 branches into the recovery flow path 652 and the waste liquid flow path 653.

[0019] The primary discharge flow path 651 has a base end connected to a drain hole, which is a through-hole provided in the bottom of the casing 5, and a terminal end connected to a three-way valve 67. The three-way valve 67 is interposed in the slurry discharge flow path 65 so as to switch the destination of the fluid flowing from the primary discharge flow path 651 between the recovery flow path 652 and the waste flow path 653. The recovery flow path 652 is provided to recover the used slurry S flowing from the primary discharge flow path 651 (i.e., return it to the slurry tank 61). The waste flow path 653 is provided to direct the cleaning liquid L flowing from the primary discharge flow path 651 toward a waste liquid container 66. The waste liquid container 66 is configured to store the cleaning liquid L. Under the control of the control unit 8, the three-way valve 67 connects the primary discharge flow path 651 and the recovery flow path 652 during planarization of the workpiece surface W1, and connects the primary discharge flow path 651 and the waste liquid flow path 653 during cleaning of the processing pad 3.

[0020] In this way, the slurry circulating supply mechanism 6 is configured to circulate the slurry S through the circulation flow path R including the slurry supply flow path 63 and the recovery flow path 652 during planarization of the workpiece surface W1. Furthermore, the slurry circulating supply mechanism 6 is configured to discharge the cleaning liquid L into the waste liquid container 66 via the waste liquid flow path 653 separated from the circulation flow path R during cleaning of the processing pad 3. The cleaning liquid supply unit 7 is provided to supply the cleaning liquid L for cleaning the processing pad 3 to the processing pad 3 during cleaning of the processing pad 3.

[0021] The control unit 8 is a microcomputer equipped with a CPU and a storage medium, and is configured to control the operations of the workpiece support unit 2, the pad support unit 4, the slurry circulating supply mechanism 6, and the cleaning liquid supply unit 7. Specifically, the control unit 8 controls the processing conditions based on the measurement results of the characteristics of the slurry S by a measurement unit 81 installed in the slurry supply flow path 63. The measurement unit 81 is a measuring device for measuring the characteristics of the slurry S flowing through the slurry supply flow path 63 and / or an introduction unit for introducing the slurry S into the measuring device. The characteristics of the slurry S to be measured include at least one of, for example, pH, conductivity, zeta potential, abrasive concentration, abrasive particle size distribution, etc. The control unit 8 also controls the operations of the supply pump 64 and the three-way valve 67.

[0022] (Surface processing method) The so-called "flow-through" method, in which the slurry S is discarded each time it is used in processing without being recovered or reused, poses environmental and cost issues due to the waste generated. On the other hand, when recovering and reusing the slurry S once used in processing, additional processing such as adding solvents or chemicals to the used slurry S to dissolve or separate the workpiece also increases costs. From this perspective, it is preferable to recycle the used slurry S almost as is. However, there is a concern that scratches may occur due to foreign matter, such as abrasive grain aggregates and the workpiece, contained in the recovered slurry S.

[0023] Therefore, the surface processing method according to the present disclosure uses the surface processing apparatus 1 having the above-described configuration to planarize the processing surface W1 while circulating and reusing the used slurry S almost as it is. Specifically, the surface processing method includes the following processes or procedures.

[0024] The workpiece W is fixed to the work support part 2. The workpiece support part 2 and the pad support part 4 are moved relatively to bring them close to each other, thereby bringing the workpiece surface W1 into contact with the processing pad 3. Typically, for example, the workpiece support part 2 is moved toward the processing pad 3 along an axial direction parallel to the rotation axis 21. A slurry S is supplied to the processing pad 3, and the workpiece W and the processing pad 3 are moved relative to each other while the slurry S containing at least abrasive grains is interposed between the processing surface W1 and the processing pad 3 (i.e., for example, the processing surface W1 is rotated around the rotation axis 21). As a result, the processing surface W1 is planarized by chemical and mechanical action. During planarization, the slurry S is circulated through the circulation flow path R. That is, the slurry S is supplied from the slurry tank 61 to the processing pad 3 through the slurry supply flow path 63, and the used slurry S is recovered through the primary discharge flow path 651 and the recovery flow path 652 and returned to the slurry tank 61. When the flattening process is completed, the workpiece support part 2 and the pad support part 4 move relative to each other to separate the workpiece surface W1 from the processing pad 3, and the workpiece W is removed from the workpiece support part 2. After every N flattening processes, the workpiece support part 2 is separated from the processing pad 3, and the processing pad 3 is cleaned by supplying a cleaning liquid L from the cleaning liquid supply part 7. N is an integer equal to or greater than 1, for example, any one of 1 to 3. At this time, the cleaning liquid L received in the casing 5 after use is discharged via a waste liquid flow path 653 separated from the circulation flow path R to a waste liquid container 66 different from the slurry tank 61.

[0025] As described above, the surface processing method according to this embodiment uses the surface processing apparatus 1 configured as described above, making it possible to recycle used slurry S without additional processing. In particular, in this embodiment, in order to maintain good processing quality and processing rate, the characteristics and handling of the slurry S are as follows. Note that the slurry S used in this embodiment is one in which manganese dioxide (MnO2) abrasive grains are dispersed in a potassium permanganate (KMnO4) solution.

[0026] For example, in terms of the processing rate, a relatively neutral slurry S with a pH of 7 to 9, which does not allow the oxidizing agent concentration to decrease easily, is used. Furthermore, to prevent abrasive grain settling, the flow rate of the slurry S flowing through the slurry supply passage 63 is set to a predetermined flow rate or higher, specifically, 0.15 m / s or higher, preferably 0.2 m / s or higher. Furthermore, a processing pad 3 capable of withstanding planarization for 10 hours or more is used. Examples of such processing pads 3 include relatively soft polishing pads made of nonwoven fabric impregnated with polyurethane resin, hard polishing pads made of foamed polyurethane, and two-layer pads made by bonding a soft polishing pad and a hard polishing pad together, all of which have high durability (e.g., high heat resistance). More specifically, a processing pad 3 having heat resistance capable of withstanding temperatures up to 90°C is preferably used.

[0027] Regarding quality, abrasive grains that are less likely to cause scratches are used, specifically abrasive grains with a Mohs hardness of 10 or less, preferably 4 or less. Furthermore, the particle size of the abrasive grains in the slurry S flowing through the slurry supply flow path 63 is set to 20 μm or less, and the concentration is set to 15% by weight or less. After each processing (i.e., assuming N=1 above), the surface of the processing pad 3 is cleaned, and the cleaning liquid L is removed from the circulation flow path R and drained, thereby removing foreign matter such as the object to be polished.

[0028] Furthermore, in this embodiment, the stirring conditions, flow rate, and processing conditions (such as temperature) are controlled while monitoring characteristics such as fluctuations in concentration and particle size distribution of the slurry S flowing through the slurry supply flow path 63. That is, the control unit 8 feedback-controls the stirring conditions, flow rate, and processing conditions based on the measurement results from the measurement unit 81.

[0029] FIG. 2 shows the results of evaluating the fluctuations in CMP processing rate for two examples and a comparative example. In FIG. 2, the horizontal axis represents the cumulative processing amount, i.e., the polishing amount from the start of use of new slurry S. The vertical axis represents the processing rate normalized by setting the initial processing rate, i.e., at the start of use of new slurry S, at 100%. The comparative example is a case in which the waste liquid flow path 653 and waste liquid container 66 in FIG. 1 are not used, and cleaning liquid L is also collected in the slurry tank 61 in addition to used slurry S and recycled for reuse. Both Example 1 and Example 2 use the polishing method according to the above embodiment, but have different processing rates. Specifically, Example 2 has a higher processing rate than the comparative example and Example 1. That is, the comparative example and Example 1 are used under low-rate conditions, while Example 2 is used under high-rate conditions. The initial processing rates are the same for the comparative example and Example 1.

[0030] As shown in FIG. 2, in the comparative example, the processing rate significantly decreased as the cumulative processing volume increased, i.e., as processing time progressed. In contrast, in the example, no significant decrease in processing rate was observed even when the cumulative processing volume increased. Specifically, the decrease in processing rate was suppressed to within 15%. Furthermore, the increase in scratches was suppressed to within 15%. Therefore, according to this embodiment, planarization processing for 10 hours or more can be performed while maintaining good processing quality and processing rate without adding or replacing the slurry S.

[0031] (Variation) The present disclosure is not limited to the above-described embodiment. Therefore, the above-described embodiment can be modified as appropriate. Representative modifications will be described below. In the following description of the modifications, differences from the above-described embodiment will be mainly described. Furthermore, the same reference numerals are used for parts that are identical or equivalent to each other in the above-described embodiment and the modifications. Therefore, in the following description of the modifications, the description of the above-described embodiment can be used as appropriate for components that have the same reference numerals as the above-described embodiment, unless there is a technical contradiction or special additional explanation.

[0032] The present disclosure is not limited to the specific device configurations shown in the above embodiments. Specifically, Fig. 1 is a simplified schematic diagram for easily explaining the outline of a surface processing device 1 according to the present disclosure and a surface processing method that can be implemented using the device. Therefore, the configuration of a surface processing device 1 that is actually manufactured and sold does not necessarily match the exemplary configuration shown in Fig. 1. Furthermore, the configuration of a surface processing device 1 that is actually manufactured and sold may be changed as appropriate from the exemplary configuration shown in Fig. 1.

[0033] For example, the processing pad 3 and the pad support part 4 that supports it may be provided so as to be rotatable. There are no particular limitations on the structures and flow path shapes of the casing 5 and the slurry circulating supply mechanism 6. Specifically, for example, the agitator 62 is not limited to a configuration using an agitator 621 that rotates inside the slurry tank 61. Furthermore, the primary discharge flow path 651 and the recovery flow path 652 may be extended in the same direction. Alternatively, the primary discharge flow path 651 and the waste liquid flow path 653 may be extended in the same direction.

[0034] Slurry S may be used as the cleaning liquid L. In this case, the cleaning liquid supply unit 7 may be omitted. In this case, a stirring mechanism may be provided in the waste liquid container 66 to return only the slurry S from the waste liquid container 66 to the slurry tank 61, and a mechanism may be provided to return the supernatant portion of the slurry S stirred in the waste liquid container 66 (i.e., the portion other than the portion at the bottom containing foreign matter) to the slurry tank 61.

[0035] The present disclosure is not limited to the specific processing contents shown in the above embodiment. That is, for example, the present disclosure does not completely exclude additional processing of used slurry S, but allows additional processing to maintain processing quality and processing rate. Specifically, for example, replenishing or replacing with new slurry S or adding additives such as a dispersant after a predetermined number of processing times or processing time may be performed as appropriate.

[0036] It goes without saying that the elements constituting the above-described embodiments are not necessarily essential unless expressly stated as essential or clearly considered essential in principle. Furthermore, when numerical values ​​such as the number, amount, and range of components are mentioned, the present disclosure is not limited to those specific numerical values ​​unless expressly stated as essential or clearly limited to specific numerical values ​​in principle. Similarly, when the shape, direction, positional relationship, etc. of components are mentioned, the present disclosure is not limited to those shapes, directions, positional relationships, etc., unless expressly stated as essential or clearly limited to specific shapes, directions, positional relationships, etc. in principle.

[0037] The modified examples are not limited to the above examples. For example, other than those exemplified above, multiple embodiments may be combined with each other as long as there is no technical contradiction. Similarly, multiple modified examples may be combined with each other as long as there is no technical contradiction.

[0038] (Disclosure perspective) As is clear from the above description of the embodiments and modifications, this specification discloses at least the following matters.

[0039] [Point 1-1] A surface processing method in which a slurry (S) containing at least abrasive grains is interposed between a processing surface (W1) of a workpiece (W) and a processing pad (3), and the workpiece and the processing pad are moved relative to each other, thereby planarizing the processing surface by chemical and mechanical action, During the planarization process, the slurry is circulated through a slurry circulation flow path (R) including a slurry supply flow path (63) for supplying the slurry to the processing pad and a recovery flow path (652) for recovering the used slurry; When the processing pad is cleaned with a cleaning liquid (L), the cleaning liquid is discharged through a waste liquid flow path (653) separated from the circulation flow path. Surface treatment method. [Point 1-2] The Mohs hardness of the abrasive grains is 10 or less. The surface processing method according to aspect 1-1. [Points 1-3] The abrasive grains are MnO2 abrasive grains. The surface processing method according to aspect 1-2. [Points 1-4] The pH of the slurry is 7 to 9. The surface processing method according to any one of Aspects 1-1 to 1-3. [Points 1-5] the particle size of the abrasive grains in the slurry flowing through the slurry supply channel is 20 μm or less; The surface processing method according to any one of Aspects 1-1 to 1-4. [Points 1-6] The concentration of the abrasive grains in the slurry is 15% by weight or less. The surface processing method according to any one of Aspects 1-1 to 1-5. [Points 1-7] The flow velocity of the slurry flowing through the slurry supply channel is 0.15 m / s or more. The surface processing method according to any one of Aspects 1-1 to 1-6. [Points 1-8] controlling processing conditions for the planarization processing based on measurement results of the properties of the slurry flowing through the slurry supply channel; The surface processing method according to any one of Aspects 1-1 to 1-7. [Points 1-9] Use the processing pad capable of withstanding the planarization processing for 10 hours or more. The surface processing method according to any one of Aspects 1-1 to 1-8. [Points 1-10] The workpiece is made of SiC. The surface processing method according to any one of Aspects 1-1 to 1-9.

[0040] [Point 2-1] A surface processing method in which a slurry (S) containing at least abrasive grains is interposed between a processing surface (W1) of a workpiece (W) and a processing pad (3), and the workpiece and the processing pad are moved relative to each other, thereby planarizing the processing surface by chemical and mechanical action, The planarization process is performed while circulating the slurry having a pH of 7 to 9 through a slurry circulation flow path (R) for the slurry, the slurry including a slurry supply flow path (63) for supplying the slurry to the processing pad and a recovery flow path (652) for recovering the used slurry. Surface treatment method. [Point 2-2] The Mohs hardness of the abrasive grains is 10 or less. The surface processing method according to aspect 2-1. [Point 2-3] The abrasive grains are MnO2 abrasive grains. The surface processing method according to aspect 2-2. [Point 2-4] During the planarization process, the slurry is circulated through the circulation flow path, When the processing pad is cleaned with a cleaning liquid (L), the cleaning liquid is discharged through a waste liquid flow path (653) separated from the circulation flow path. The surface processing method according to any one of Aspects 2-1 to 2-3. [Point 2-5] the particle size of the abrasive grains in the slurry flowing through the slurry supply channel is 20 μm or less; The surface processing method according to any one of Aspects 2-1 to 2-4. [Point 2-6] The concentration of the abrasive grains in the slurry is 15% by weight or less. The surface processing method according to any one of Aspects 2-1 to 2-5. [Point 2-7] The flow velocity of the slurry flowing through the slurry supply channel is 0.15 m / s or more. The surface processing method according to any one of Aspects 2-1 to 2-6. [Point 2-8] controlling processing conditions for the planarization processing based on measurement results of the properties of the slurry flowing through the slurry supply channel; The surface processing method according to any one of Aspects 2-1 to 2-7. [Point 2-9] Use the processing pad capable of withstanding the planarization processing for 10 hours or more. The surface processing method according to any one of Aspects 2-1 to 2-8. [Point 2-10] The workpiece is made of SiC. The surface processing method according to any one of Aspects 2-1 to 2-9.

[0041] [Point 3-1] A surface processing method in which a slurry (S) containing at least abrasive grains is interposed between a processing surface (W1) of a workpiece (W) and a processing pad (3), and the workpiece and the processing pad are moved relative to each other, thereby planarizing the processing surface by chemical and mechanical action, The planarization process is performed while circulating the slurry through a slurry circulation flow path (R) including a slurry supply flow path (63) for supplying the slurry to the processing pad and a recovery flow path (652) for recovering the used slurry; The flow velocity of the slurry flowing through the slurry supply channel is set to 0.15 m / s or more. Surface treatment method. [Point 3-2] The Mohs hardness of the abrasive grains is 10 or less. The surface processing method according to aspect 3-1. [Point 3-3] The abrasive grains are MnO2 abrasive grains. The surface processing method according to aspect 3-2. [Point 3-4] The pH of the slurry is 7 to 9. The surface processing method according to any one of Aspects 3-1 to 3-3. [Point 3-5] During the planarization process, the slurry is circulated through the circulation flow path, When the processing pad is cleaned with a cleaning liquid (L), the cleaning liquid is discharged through a waste liquid flow path (653) separated from the circulation flow path. The surface processing method according to any one of Aspects 3-1 to 3-4. [Point 3-6] the particle size of the abrasive grains in the slurry flowing through the slurry supply channel is 20 μm or less; The surface processing method according to any one of Aspects 3-1 to 3-5. [Point 3-7] The concentration of the abrasive grains in the slurry is 15% by weight or less. The surface processing method according to any one of Aspects 3-1 to 3-6. [Point 3-8] controlling processing conditions for the planarization processing based on measurement results of the properties of the slurry flowing through the slurry supply channel; The surface processing method according to any one of Aspects 3-1 to 3-7. [Point 3-9] Use the processing pad capable of withstanding the planarization processing for 10 hours or more. The surface processing method according to any one of Aspects 3-1 to 3-8. [Point 3-10] The workpiece is made of SiC. The surface processing method according to any one of Aspects 3-1 to 3-9. [Explanation of symbols]

[0042] 1 Surface processing equipment 3 Processing pad 63 Slurry supply channel 652 Recovery channel 653 Waste flow path L cleaning solution R Circulation flow path S Slurry W Workpiece W1 Work surface

Claims

1. A surface processing method for planarizing a surface (W1) of a workpiece (W) by chemical and mechanical action by moving the workpiece and a processing pad (3) relative to each other while interposing a slurry (S) containing at least abrasive grains between the workpiece and the processing pad, the method comprising: During the planarization process, the slurry is circulated through a slurry circulation flow path (R) including a slurry supply flow path (63) for supplying the slurry to the processing pad and a recovery flow path (652) for recovering the used slurry; When the processing pad is cleaned with a cleaning liquid (L), the cleaning liquid is discharged through a waste liquid flow path (653) separated from the circulation flow path. Surface processing method.

2. The Mohs hardness of the abrasive grains is 10 or less. The surface processing method according to claim 1.

3. The abrasive grains are MnO ２ It is an abrasive grain, The surface processing method according to claim 2.

4. The pH of the slurry is 7 to 9. The surface processing method according to claim 1.

5. the particle size of the abrasive grains in the slurry flowing through the slurry supply channel is 20 μm or less; The surface processing method according to claim 1.

6. The concentration of the abrasive grains in the slurry is 15% by weight or less. The surface processing method according to claim 1.

7. The flow velocity of the slurry flowing through the slurry supply channel is 0.15 m / s or more. The surface processing method according to claim 1.

8. controlling processing conditions for the planarization processing based on measurement results of the properties of the slurry flowing through the slurry supply channel; The surface processing method according to claim 1.

9. Use the processing pad capable of withstanding the planarization processing for 10 hours or more. The surface processing method according to claim 1.

10. The workpiece is made of SiC. The surface processing method according to claim 1.

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