Machining device and machining method

Abstract

The present invention addresses the problem of providing a novel grinding device that causes little damage to a workpiece and can perform machining with high efficiency. The processing device is provided with: a grindstone in which abrasive grains are dispersed in a binder containing a thermoplastic resin; and a temperature adjusting mechanism for adjusting the temperature of the contact surface between the grinding tool and the object to be processed according to the processing mode.

Description

[0001] This application claims priority based on Japanese Patent Application No. 2024-162013 filed on September 19, 2024. The entire contents of this Japanese application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to a processing device and a processing method using an abrasive tool. BACKGROUND

[0003] In mirror processing of difficult-to-grind materials such as sapphire, silicon carbide, and gallium nitride, generally, grinding is performed first using an abrasive tool with a small grain size, and then polishing is performed using an abrasive slurry. Although the processing speed of grinding processing is fast, the surface is still rough. Although the surface roughness can be improved by subsequent polishing, the processing takes a long time. A technique is known in which grinding and polishing of a difficult-to-grind material are performed in the same process by using an abrasive tool in which abrasive grains are dispersed in a mixture of rosin or the like and a synthetic resin or the like having a softening point of 200°C or lower (Patent Literature 1).

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2016-198878 SUMMARY

[0005] A processing technique that causes less damage to a processed object and enables processing with high efficiency is desired. An object of the present application is to provide a novel grinding device and a grinding method that cause less damage to a processed object and enable processing with high efficiency.

[0006] According to an aspect of the present application, there is provided a processing device including:

[0007] an abrasive tool in which abrasive grains are dispersed in a binder containing a thermoplastic resin; and

[0008] a temperature adjustment mechanism that adjusts the temperature of the contact surface of the abrasive tool with a processed object according to the processing method.

[0009] According to another aspect of the present application, there is provided a processing method of processing a processed object using an abrasive tool in which abrasive grains are dispersed in a binder containing a thermoplastic resin, the processing method including:

[0010] rough grinding a surface of the processed object by the abrasive tool; and

[0011] subsequently, raising the temperature of the contact surface of the abrasive tool with the processed object, thereby performing finish processing.

[0012] According to still another aspect of the present application, there is provided a processing device including:

[0013] An abrasive tool in which abrasive grains are dispersed in a binder containing a thermoplastic resin; and

[0014] A temperature adjusting mechanism which adjusts the temperature of the abrasive tool according to the processing mode.

[0015] Effects of the Invention

[0016] The thermoplastic resin has a property in which the vibration absorption coefficient tan δ depends on temperature. If the binder of the abrasive grains contains the thermoplastic resin, the vibration absorption coefficient tan δ of the binder also changes with temperature. Under conditions in which the vibration absorption coefficient tan δ is relatively small, the elastic force is dominant over the viscous force, and the processing speed can be increased. Under conditions in which the vibration absorption coefficient tan δ is relatively large, the viscous force is dominant over the elastic force, and the damage to the processed object can be reduced. By adjusting the temperature of the contact surface of the abrasive tool with the processed object or the abrasive tool, the same abrasive tool can be used to process under either conditions of high processing speed and low damage. By increasing the processing speed at the initial stage and then processing under conditions of low damage, processing with low damage and high efficiency can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a partial cross-sectional view of the abrasive tool 10 used in the processing apparatus based on the first embodiment.

[0018] Figure 2 is a graph showing the relationship between the vibration absorption coefficient tan δ of the binder 11 and temperature.

[0019] Figure 3 In the figure: Figure 3 A is a schematic cross-sectional view (partially schematic) of a processing apparatus based on the first embodiment, Figure 3 B is a bottom view of the abrasive tool flange 31.

[0020] Figure 4 is a flowchart showing the steps of the processing method based on the first embodiment.

[0021] Figure 5 is a schematic cross-sectional view (partially schematic) of a processing apparatus based on the second embodiment.

[0022] Figure 6 In the figure: Figure 6 A is a schematic cross-sectional view (partially schematic) of a processing apparatus based on the third embodiment, Figure 6 B is a bottom view of the abrasive tool flange 31.

[0023] In the attached diagram: 10-Abrasive, 11-Binder, 12-Abrasive grain, 20-Temperature control mechanism, 21-High temperature container, 22-Low temperature container, 24, 25-On / off valve, 27-Selective supply path, 28-Container, 29-On / off valve, 30-Supply path, 31-Abrasive flange, 31A-Lower disc-shaped component, 31B-Upper disc-shaped component, 33-Abrasive shaft, 35-Flow path, 35A-Outlet, 37-Heating device, 50-Workpiece. Detailed Implementation

[0024] [First Embodiment]

[0025] refer to Figures 1-4 The processing apparatus and processing method based on the first embodiment will be described.

[0026] The processing apparatus based on the first embodiment uses a grinding wheel to grind and polish the workpiece, such as a high-hardness semiconductor wafer like a SiC wafer.

[0027] Figure 1 This is a cross-sectional view of a portion of the abrasive 10 used in the processing apparatus based on the first embodiment. The abrasive 10 (such as a grinding wheel) includes a binder (adhesive) 11 containing a thermoplastic resin and a plurality of abrasive grains 12 dispersed in the binder 11. For example, diamond is used as one of the abrasive grains 12. A portion of the abrasive grains 12 is exposed on the surface of the abrasive 10 facing the workpiece 50.

[0028] Figure 2 This is a graph showing the relationship between the vibration absorption coefficient tanδ of adhesive 11 and temperature. The horizontal axis represents temperature in units of [°C], and the vertical axis represents the vibration absorption coefficient (viscoelastic loss tangent) tanδ. Figure 2 In the graph shown, solid lines a, b, and c represent the vibration absorption coefficients tanδ of the three adhesives 11 used in the abrasive 10 according to the first embodiment. The softening points of the adhesives 11 shown by solid lines a, b, and c are 77.5°C, 98.9°C, and 135.5°C, respectively. Dashed lines d and e represent the vibration absorption coefficients tanδ of the resin adhesive and ceramic adhesive conventionally used as adhesives 11.

[0029] The vibration absorption coefficient tanδ of resin adhesives and ceramic adhesives used in the binder 11 in the past hardly changes with temperature. In contrast, the vibration absorption coefficient tanδ of the binder 11 containing thermoplastic resin used in the abrasive 10 based on the first embodiment changes greatly with temperature. As the temperature increases from 0°C, the vibration absorption coefficient tanδ increases, showing a maximum value at a certain temperature, and then decreases with further increases in temperature.

[0030] A larger vibration absorption coefficient tanδ means that the viscous force becomes relatively larger relative to the elastic force. If the viscous force is larger, the stress applied to the workpiece 50 during machining is more easily mitigated, enabling machining that causes less damage to the workpiece 50. Conversely, within the range where the vibration absorption coefficient tanδ is small, the elastic force becomes larger, thus allowing for increased machining speed.

[0031] For example, processing speed can be increased by processing under conditions where the vibration absorption coefficient tanδ is relatively small (e.g., tanδ is 0.1 or less). To reduce damage to the workpiece 50, processing is preferably performed within a range where the vibration absorption coefficient tanδ is relatively large (e.g., tanδ is 0.4 or more). When using the adhesive shown by solid line a, the temperature can be set to approximately 25°C to 40°C; when using the adhesive shown by solid line b, the temperature can be set to approximately 35°C to 45°C; and when using the adhesive shown by solid line c, the temperature can be set to approximately 55°C to 95°C.

[0032] Figure 3 middle, Figure 3 A is a schematic cross-sectional view (partial schematic diagram) of the processing apparatus based on the first embodiment. Figure 3 B is a bottom view of the mold flange 31. Figure 3 The sectional view at point 3A-3A in B corresponds to... Figure 3 A.

[0033] The processing apparatus based on the first embodiment includes a temperature regulating mechanism 20, grinding wheels 10, a grinding wheel flange 31, and a grinding wheel shaft 33. The grinding wheel flange 31 is disc-shaped, and a plurality of cylindrical grinding wheels 10 are mounted on one of its surfaces (hereinafter referred to as the lower surface). The grinding wheels 10 are arranged at equal intervals in the circumferential direction at a position slightly inward of the outer perimeter of the lower surface of the grinding wheel flange 31. Each grinding wheel 10 has a through hole along its central axis. The front ends of the plurality of grinding wheels 10 contact the workpiece 50 being processed.

[0034] The grinding wheel flange 31 includes a lower disc-shaped component 31A and an upper disc-shaped component 31B. The lower disc-shaped component 31A and the upper disc-shaped component 31B are airtightly connected near the outer edges of their opposing surfaces by an O-ring or the like, forming a flat flow path in the inner region.

[0035] A grinding wheel shaft 33 is fixed at the center of the upper disc-shaped component 31B. An axially extending flow path 35 is formed on the grinding wheel shaft 33. If the grinding wheel shaft 33 rotates, the grinding wheel flange 31 also rotates, resulting in multiple grinding wheels 10 rotating around the central axis of the grinding wheel shaft 33. The surface of the workpiece 50 is ground and polished by combining the rotation of the grinding wheel shaft 33 with the rotation of the workpiece 50.

[0036] The temperature regulating mechanism 20 has the function of adjusting the temperature of the contact surface between the abrasive 10 and the workpiece 50 according to the machining method (e.g., roughing, finishing, etc.). Furthermore, during machining, fluid flows through the through-hole provided in the abrasive 10, so the temperature of the abrasive 10 itself can also be adjusted by the temperature regulating mechanism 20. Next, the structure of the temperature regulating mechanism 20 will be described.

[0037] The temperature control mechanism 20 includes a high-temperature container 21 and a low-temperature container 22. Fluids, such as water, are contained in both containers. The temperature of the fluid contained in the high-temperature container 21 is higher than the temperature of the fluid contained in the low-temperature container 22. The fluids contained in the high-temperature container 21 and the low-temperature container 22 are selectively supplied to a flow path 35 provided on the grinding wheel shaft 33 via a selective supply path 27. The fluid supplied to the flow path 35 is supplied to the contact surface between the grinding wheel 10 and the workpiece 50 through a flat flow path within the grinding wheel flange 31.

[0038] For example, the selective supply path 27 includes an on / off valve 24 inserted in the flow path connected to the high-temperature container 21, an on / off valve 25 inserted in the flow path connected to the low-temperature container 22, and a flow path where these two flow paths merge. If the on / off valve 24 on the high-temperature container 21 side is opened and the on / off valve 25 on the low-temperature container 22 side is closed, the fluid contained in the high-temperature container 21 is selectively supplied to the contact surface between the abrasive 10 and the workpiece 50. Conversely, if the on / off valve 24 on the high-temperature container 21 side is closed and the on / off valve 25 on the low-temperature container 22 side is opened, the fluid contained in the low-temperature container 22 is selectively supplied to the contact surface between the abrasive 10 and the workpiece 50.

[0039] The temperature of the fluid contained in the cryogenic container 22 is preferably adjusted to make the vibration absorption coefficient tanδ of the binder 11 of the abrasive 10 a sufficiently small value, for example, 0.1 or less. The temperature of the fluid contained in the high-temperature container 21 is preferably adjusted to make the vibration absorption coefficient tanδ of the binder 11 of the abrasive 10 a larger value, for example, 0.4 or more.

[0040] Figure 4This is a flowchart illustrating the steps of the processing method based on the first embodiment. First, while supplying fluid contained in the cryogenic container 22 to the contact surface between the abrasive 10 and the workpiece 50, rough processing is performed on the surface of the workpiece 50 (step S1). At this time, the temperature of the fluid is adjusted so that the binder 11 of the abrasive 10 ( Figure 1 The vibration absorption coefficient tanδ becomes less than 0.1.

[0041] Next, while supplying the fluid contained in the high-temperature container 21 to the contact surface between the abrasive 10 and the workpiece 50, the surface of the workpiece 50 is finished (step S2). At this time, the temperature of the fluid is adjusted to allow the binder 11 of the abrasive 10 to adhere to the surface. Figure 1 The vibration absorption coefficient tanδ of the abrasive becomes 0.4 or higher. Thus, after rough machining, the temperature of the contact surface between the abrasive 10 and the workpiece 50 is raised for finishing. That is, the temperature regulating mechanism 20 operates to ensure that the temperature of the contact surface is higher during finishing than during rough machining.

[0042] Next, the superior effects of the first embodiment will be explained.

[0043] Depending on the processing method, such as roughing or finishing, the relationship between the grinding wheel 10 and the workpiece 50 is changed. Figure 1 The temperature of the contact surface of the abrasive 10, the adhesive 11 ( Figure 1 The vibration absorption coefficient tanδ of the material changes. Machining with a small vibration absorption coefficient tanδ increases machining speed. Machining with a large vibration absorption coefficient tanδ reduces damage to the workpiece 50. Since the same grinding wheel 10 can be used for both roughing and finishing consecutively, machining efficiency is improved.

[0044] By selectively supplying a cryogenic fluid (e.g., cryogenic water) contained in the cryogenic container 22 and a fluid (e.g., hot water) contained in the hot-temperature container 21 to the contact surface between the abrasive 10 and the workpiece 50, the temperature of the contact surface can be easily adjusted. In actual processing, the temperature of the contact surface can be easily adjusted to around 30°C. Therefore, as a binder 11 ( Figure 1 Preferably, a thermoplastic resin exhibiting the maximum value of the vibration absorption coefficient tanδ at around 30°C is used. By mixing multiple thermoplastic resins with different temperature characteristics of vibration absorption coefficient tanδ, the temperature at which the vibration absorption coefficient tanδ exhibits its maximum value can be adjusted.

[0045] The processing apparatus and processing method based on the first embodiment can be applied to various processes where high-efficiency, low-damage processing is desired. For example, they can be applied to surface processing of semiconductor wafers such as SiC and GaN, which are power semiconductor materials, and mold processing using hard materials.

[0046] Next, a variation based on the first embodiment will be described.

[0047] In the first embodiment, water is used as the fluid for adjusting the temperature of the contact surface between the abrasive 10 and the workpiece 50, but other fluids, such as oil, can also be used. Furthermore, a slurry for chemical mechanical polishing (CMP) can be used as the fluid contained in the high-temperature container 21. Thus, slurry-based polishing can be performed during finishing.

[0048] [Second Embodiment]

[0049] Next, refer to Figure 5 The processing apparatus and processing method based on the second embodiment will be described below. Hereinafter, the referenced... Figures 1-4 The description of the same structure as the processing apparatus and processing method based on the first embodiment is omitted.

[0050] Figure 5 This is a schematic cross-sectional view (partial schematic diagram) of the processing apparatus based on the second embodiment. In the first embodiment ( Figure 3 In embodiment A), the temperature regulating mechanism 20 includes a high-temperature container 21 and a low-temperature container 22. However, in the second embodiment, the temperature regulating mechanism 20 includes a single container 28. Fluid is contained in container 28 and is supplied to flow path 35 within the mold shaft 33 via supply path 30. An on / off valve 29 is inserted into supply path 30. A heating device 37 heats the fluid flowing through supply path 30.

[0051] The heating device 37 is not activated during rough machining, but is activated during finish machining to supply the heated fluid to the contact surface between the grinding wheel 10 and the workpiece 50.

[0052] Next, the superior effects of the second embodiment will be explained.

[0053] In the second embodiment, similarly to the first embodiment, the temperature of the contact surface between the abrasive 10 and the workpiece 50 can also be adjusted. This enables high-efficiency, high-speed roughing and low-damage finishing.

[0054] [Third Embodiment]

[0055] Next, refer to Figure 6 A and Figure 6B. The processing apparatus based on the third embodiment will be described. Hereinafter, the referenced... Figures 1-4 The description of the same structure as the processing apparatus and processing method based on the first embodiment is omitted.

[0056] Figure 6 middle, Figure 6 A is a schematic cross-sectional view (partial schematic diagram) of the processing apparatus based on the third embodiment. Figure 6 B is a bottom view of the mold flange 31. Figure 6 The sectional view at point 6A-6A in B corresponds to... Figure 6 A.

[0057] In the first embodiment ( Figure 3 A, Figure 3 In embodiment B), a cylindrical abrasive 10 with a central through hole is used, but in the third embodiment, a block abrasive 10 is used. Multiple abrasive 10s curved along the cylindrical side are positioned slightly inside the edge of the lower surface of the abrasive flange 31 and are arranged at equal intervals in the circumferential direction. The multiple abrasive 10s are arranged integrally along a single cylindrical surface. An outlet 35A is provided slightly inside the circumference of the position where the abrasive 10s are positioned. Fluid supplied to the flat flow path within the abrasive flange 31 flows out from the outlet 35A and is supplied to the contact surface between the abrasive 10 and the workpiece 50.

[0058] Next, the superior effects of the third embodiment will be explained.

[0059] In the third embodiment, similar to the first embodiment, the temperature of the contact surface between the abrasive 10 and the workpiece 50 can also be adjusted. This enables high-efficiency, high-speed roughing and low-damage finishing.

[0060] The above embodiments are exemplary, and the structures shown in different embodiments can be partially replaced or combined. Similar effects based on similar structures in multiple embodiments are not mentioned one by one in each embodiment. The present invention is not limited to the above embodiments. For example, those skilled in the art should understand that various changes, improvements, combinations, etc., are possible.

Claims

1. A processing apparatus comprising: Abrasive tools in which abrasive grains are dispersed in a binder containing thermoplastic resin; and A temperature regulating mechanism that adjusts the temperature of the contact surface between the abrasive and the workpiece according to the processing method.

2. The processing apparatus according to claim 1, wherein, During finishing, the temperature regulating mechanism ensures that the temperature of the contact surface is higher than that during roughing.

3. The processing apparatus according to claim 1 or 2, wherein, The temperature regulating mechanism includes: High-temperature containers used to hold fluids; A cryogenic container for containing a fluid whose temperature is lower than that of the fluid contained in the high-temperature container; and A selective supply path for selectively supplying fluid contained in the high-temperature container and the low-temperature container to the contact surface.

4. The processing apparatus according to claim 2, wherein, The temperature regulating mechanism includes: A container used to hold fluids; A supply path for supplying fluid contained in the container to the contact surface; and A heating device for heating the fluid flowing through the supply path.

5. A processing method comprising processing an object using an abrasive tool in which abrasive grains are dispersed in a binder containing a thermoplastic resin, the processing method comprising the following steps: The surface of the workpiece is roughly ground using the abrasive tool; and Then, the temperature of the contact surface between the abrasive and the workpiece is increased to perform finishing.

6. A processing apparatus comprising: Abrasive tools in which abrasive grains are dispersed in a binder containing thermoplastic resin; and A temperature regulating mechanism that adjusts the temperature of the grinding wheel according to the processing method.

Images