PROCESSING DEVICE AND PROCESSING METHOD

Abstract

The present invention relates to a processing device which includes: a grindstone in which abrasive grains are dispersed in a binder containing a thermoplastic resin; and a temperature control mechanism that adjusts a temperature of a contact surface between the grindstone and a processing object according to an aspect of processing.

Claims

1. A processing device comprising: a grindstone in which abrasive grains are dispersed in a binder containing a thermoplastic resin; and a temperature control mechanism that adjusts a temperature of a contact surface between the grindstone and a processing object according to an aspect of processing.

2. The processing device according to claim 1, wherein the temperature control mechanism raises the temperature of the contact surface higher during finish processing than during rough processing.

3. The processing device according to claim 1, wherein the temperature control mechanism includes a high temperature container that accommodates a fluid, a low temperature container that accommodates a fluid having a temperature lower than a temperature of the fluid accommodated in the high temperature container, and a selective supply path that selectively supplies the fluids accommodated in the high temperature container and the low temperature container to the contact surface.

4. The processing device according to claim 3, wherein the selective supply path includes an opening and closing valve inserted in a flow path connected to the high temperature container, an opening and closing valve inserted in a flow path connected to the low temperature container, and a flow path where the flow path connected to the high temperature container and the flow path connected to the low temperature container merge.

5. The processing device according to claim 2, wherein the temperature control mechanism includes a container that accommodates a fluid, a supply path that supplies the fluid accommodated in the container to the contact surface, and a heating device that heats the fluid flowing through the supply path.

6. The processing device according to claim 5, wherein the heating device is operated when the finish processing is performed, and the fluid heated by the heating device is supplied to the contact surface between the grindstone and the processing object.

7. The processing device according to claim 1, further comprising: a grindstone flange; and a grindstone shaft.

8. The processing device according to claim 7, wherein the grindstone flange has a disc shape, and a plurality of columnar grindstones are attached to a lower surface of the grindstone flange.

9. The processing device according to claim 8, wherein the grindstones are disposed at equal intervals in a circumferential direction inside an outer peripheral line of the lower surface of the grindstone flange.

10. The processing device according to claim 8, wherein the grindstone flange includes a lower disc-shaped member and an upper disc-shaped member.

11. The processing device according to claim 10, wherein the grindstone shaft is fixed to a center portion of the upper disc-shaped member.

12. The processing device according to claim 11, wherein a flow path extending in an axial direction is formed in the grindstone shaft.

13. A processing method of processing a processing object using a grindstone in which abrasive grains are dispersed in a binder containing a thermoplastic resin, the method comprising: roughly grinding a surface of the processing object with the grindstone; and thereafter, raising a temperature of a contact surface between the grindstone and the processing object to perform finish processing.

14. A processing device comprising: a grindstone in which abrasive grains are dispersed in a binder containing a thermoplastic resin; and a temperature control mechanism that adjusts a temperature of the grindstone according to an aspect of processing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a cross-sectional view of a portion of a grindstone 10 used in a processing device according to a first example.

[0008] FIG. 2 is a graph illustrating a relationship between the vibration absorption coefficient tan of a binder 11 and the temperature.

[0009] FIG. 3A is a schematic cross-sectional view (a partial schematic view) of the processing device according to the first example, and FIG. 3B is a bottom view of a grindstone flange 31.

[0010] FIG. 4 is a flowchart illustrating the procedure of a processing method according to the first example.

[0011] FIG. 5 is a schematic cross-sectional view (a partial schematic view) of a processing device according to a second example.

[0012] FIG. 6A is a schematic cross-sectional view (a partial schematic view) of a processing device according to a third example, and FIG. 6B is a bottom view of a grindstone flange 31.

DETAILED DESCRIPTION

[0013] The thermoplastic resin has a property in which a vibration absorption coefficient tan depends on the temperature. When the binder of the abrasive grain contains the thermoplastic resin, the vibration absorption coefficient tan of the binder also changes depending on the temperature. Under the condition where the vibration absorption coefficient tan is relatively small, an elastic force is dominant over a viscous force, and the processing speed can be increased. Under the condition where the vibration absorption coefficient tan is relatively large, the viscous force is dominant over the elastic force, and the damage to the processing object can be reduced. By adjusting the contact surface between the grindstone and the processing object or the temperature of the grindstone, it is possible to use the same grindstone to perform processing under any of the conditions of high speed processing and low damage processing. By increasing the processing speed in the initial stage and then performing the processing under the condition of low damage, it is possible to perform the processing with low damage and high efficiency.

FIRST EXAMPLE

[0014] A processing device and a processing method according to a first example will be described with reference to FIGS. 1 to 4.

[0015] The processing device according to the first example grinds and polishes a processing object, for example, a high-hardness semiconductor wafer such as a SiC wafer, with a grindstone.

[0016] FIG. 1 is a cross-sectional view of a portion of a grindstone 10 used for the processing device according to the first example. The grindstone 10 includes a binder (bond) 11 containing a thermoplastic resin and a plurality of abrasive grains 12 dispersed in the binder 11. For example, diamond is used as the abrasive grain 12. A part of the abrasive grains 12 are exposed on a surface of the grindstone 10 facing the processing object 50.

[0017] FIG. 2 is a graph illustrating a relationship between the vibration absorption coefficient tan of the binder 11 and the temperature. The horizontal axis represents temperature in units of [C], and the vertical axis represents the vibration absorption coefficient (viscoelastic loss tangent) tan . Each of solid lines a, b, and c in the graph illustrated in FIG. 2 indicates the vibration absorption coefficient tan of the three types of binders 11 of the grindstone 10 according to the first example. Each of the softening points of the binders 11 illustrated by the solid lines a, b, and c is 77.5C, 98.9C, and 135.5C. Each of broken lines d and e indicates the vibration absorption coefficient tan of a resinoid bond and a vitrified bond used as the binder 11 in the related art.

[0018] The vibration absorption coefficient tan of the resinoid bond and the vitrified bond used for the binder 11 from the related art does not substantially change with the temperature. In contrast, the vibration absorption coefficient tan of the binder 11 containing the thermoplastic resin used for the grindstone 10 according to the first example significantly changes with the temperature. As the temperature increases from 0C, the vibration absorption coefficient tan increases, the vibration absorption coefficient tan indicates a maximum value at a certain temperature, and then the vibration absorption coefficient tan decreases with the increase in temperature.

[0019] The increase in the vibration absorption coefficient tan means that the viscous force is relatively increased with respect to the elastic force. When the viscous force is increased, the stress applied to the processing object 50 during the processing is likely to be alleviated, and it is possible to perform the processing with less damage to the processing object 50. On the contrary, in a range where the vibration absorption coefficient tan is small, since the elastic force increases, the processing speed can be improved.

[0020] For example, the processing speed can be improved by performing the processing under a condition where the vibration absorption coefficient tan is relatively small (for example, the vibration absorption coefficient tan is 0.1 or less). In order to reduce the damage applied to the processing object 50, for example, it is preferable to perform the processing in a range under the condition where the vibration absorption coefficient tan is relatively large (for example, the vibration absorption coefficient tan is 0.4 or more). In a case of using the binder indicated by the solid line a, the temperature may be set to approximately 25C to 40C, in a case of using the binder indicated by the solid line b, the temperature may be set to approximately 35C to 45C, and in a case of using the binder indicated by the solid line c, the temperature may be set to approximately 55C to 95C.

[0021] FIG. 3A is a schematic cross-sectional view (a partial schematic view) of the processing device according to the first example, and FIG. 3B is a bottom view of a grindstone flange 31. The cross-sectional view taken along a one-dot chain line 3A-3A of FIG. 3B corresponds to FIG. 3A.

[0022] The processing device according to the first example includes a temperature control mechanism 20, the grindstone 10, the grindstone flange 31, and a grindstone shaft 33. The grindstone flange 31 has a disc shape, and a plurality of columnar grindstones 10 are attached to one surface (hereinafter, referred to as a lower surface). The grindstones 10 are disposed at equal intervals in a circumferential direction slightly inside an outer peripheral line of a lower surface of the grindstone flange 31. Each of the grindstones 10 is provided with a through-hole along a center axis. The tip ends of the plurality of grindstones 10 come into contact with the processing object 50.

[0023] The grindstone flange 31 includes a lower disc-shaped member 31A and an upper disc-shaped member 31B. The lower disc-shaped member 31A and the upper disc-shaped member 31B are airtightly connected to each other by an O-ring or the like in the vicinity of the outer periphery of the surfaces facing each other, and a flat plate-shaped flow path is formed in an inner region.

[0024] The grindstone shaft 33 is fixed to a center portion of the upper disc-shaped member 31B. A flow path 35 extending in the axial direction is formed in the grindstone shaft 33. When the grindstone shaft 33 rotates, the grindstone flange 31 also rotates. As a result, the plurality of grindstones 10 orbit around the center axis of the grindstone shaft 33. The rotation of the grindstone shaft 33 and the rotation of the processing object 50 are combined with each other, and the surface of the processing object 50 is ground and polished.

[0025] The temperature control mechanism 20 has a function of adjusting the temperature of the contact surface between the grindstone 10 and the processing object 50 according to the aspect of the processing (for example, rough processing, finish processing, and the like). In addition, during the processing, since the fluid flows through the through-hole provided in the grindstone 10, it can also be said that the temperature of the grindstone 10 is adjusted by the temperature control mechanism 20. Next, a configuration of the temperature control mechanism 20 will be described.

[0026] The temperature control mechanism 20 includes a high temperature container 21 and a low temperature container 22. A fluid, for example, water is accommodated in the high temperature container 21 and the low temperature container 22. The temperature of the fluid accommodated in the high temperature container 21 is higher than the temperature of the fluid accommodated in the low temperature container 22. The fluid accommodated in the high temperature container 21 and the low temperature container 22 is selectively supplied to the flow path 35 provided in the grindstone shaft 33 through a selective supply path 27. The fluid supplied to the flow path 35 is supplied to the contact surface between the grindstone 10 and the processing object 50 through a flat plate-shaped flow path in the grindstone flange 31.

[0027] For example, the selective supply path 27 includes an opening and closing valve 24 inserted in the flow path connected to the high temperature container 21, an opening and closing valve 25 inserted in the flow path connected to the low temperature container 22, and a flow path in which the two flow paths merge. When the opening and closing valve 24 on the high temperature container 21 side is opened and the opening and closing valve 25 on the low temperature container 22 side is closed, the fluid accommodated in the high temperature container 21 is selectively supplied to the contact surface between the grindstone 10 and the processing object 50. On the contrary, when the opening and closing valve 24 on the high temperature container 21 side is closed and the opening and closing valve 25 on the low temperature container 22 side is opened, the fluid accommodated in the low temperature container 22 is selectively supplied to the contact surface between the grindstone 10 and the processing object 50.

[0028] It is preferable that the temperature of the fluid accommodated in the low temperature container 22 is adjusted so that the vibration absorption coefficient tan of the binder 11 of the grindstone 10 has a sufficiently small value, for example, 0.1 or less. It is preferable that the temperature of the fluid accommodated in the high temperature container 21 is adjusted so that the vibration absorption coefficient tan of the binder 11 of the grindstone 10 has a large value, for example, 0.4 or more.

[0029] FIG. 4 is a flowchart illustrating the procedure of the processing method according to the first example. First, rough processing on the surface of the processing object 50 is performed while supplying the fluid accommodated in the low temperature container 22 to the contact surface between the grindstone 10 and the processing object 50 (step S1). In this case, the temperature of the fluid is adjusted so that the vibration absorption coefficient tan of the binder 11 of the grindstone 10 (FIG. 1) is 0.1 or less.

[0030] Next, finish processing on the surface of the processing object 50 is performed while the fluid accommodated in the high temperature container 21 is supplied to the contact surface between the grindstone 10 and the processing object 50 (step S2). In this case, the temperature of the fluid is adjusted so that the vibration absorption coefficient tan of the binder 11 of the grindstone 10 (FIG. 1) is 0.4 or more. In this manner, after the rough processing is performed, the temperature of the contact surface between the grindstone 10 and the processing object 50 is raised to perform the finish processing. That is, the temperature control mechanism 20 operates to raise the temperature of the contact surface higher during the finish processing than during the rough processing.

[0031] Next, an excellent effect of the first example will be described.

[0032] When the temperature of the contact surface between the grindstone 10 and the processing object 50 (FIG. 1) is changed according to the aspect of the processing, for example, the aspect of the rough processing, the finish processing, or the like, the vibration absorption coefficient tan of the binder 11 of the grindstone 10 (FIG. 1) is changed. When the processing is performed under the condition that the vibration absorption coefficient tan is small, it is possible to increase the processing speed. When the processing is performed under the condition that the vibration absorption coefficient tan is large, it is possible to reduce the damage applied to the processing object 50. Since it is possible to continuously perform the rough processing and the finish processing by using the common grindstone 10, it is possible to improve the efficiency of the processing.

[0033] The low temperature fluid accommodated in the low temperature container 22, for example, low temperature water, and the fluid accommodated in the high temperature container 21, for example, high temperature water are selectively supplied to the contact surface between the grindstone 10 and the processing object 50. Therefore, the temperature of the contact surface can be easily adjusted. In actual processing, it is easy to adjust the temperature of the contact surface to approximately 30C. Therefore, as the binder 11 (FIG. 1), it is preferable to use a thermoplastic resin in which the vibration absorption coefficient tan indicates a maximum value at approximately 30C. By mixing a plurality of thermoplastic resins having different temperature characteristics of the vibration absorption coefficient tan , it is possible to adjust the temperature at which the vibration absorption coefficient tan has a maximum value.

[0034] The processing device and the processing method according to the first example can be applied to various types of processing in which it is desired to perform low damage processing at a high efficiency. For example, the present invention can be applied to surface processing of a semiconductor wafer such as SiC and GaN, which is a power semiconductor material, and the processing of a die using a hard material.

[0035] Next, a modification example of the first example will be described.

[0036] In the first example, water is used as the fluid for adjusting the temperature of the contact surface between the grindstone 10 and the processing object 50, and other fluids, for example, oil or the like may be used. Furthermore, as the fluid accommodated in the high temperature container 21, a slurry used for chemical mechanical polishing (CMP) may be used. As a result, the slurry can be used to perform the polishing in the finish processing.

SECOND EXAMPLE

[0037] Next, a processing device and a processing method according to a second example will be described with reference to FIG. 5. Hereinafter, a description of a configuration common to the processing device and the processing method according to the first example described with reference to FIGS. 1 to 4 will be omitted.

[0038] FIG. 5 is a schematic cross-sectional view (a partial schematic view) of a processing device according to a second example. In the first example (FIG. 3A), the temperature control mechanism 20 includes the high temperature container 21 and the low temperature container 22. However, in the second example, the temperature control mechanism 20 includes one container 28. A fluid is accommodated in the container 28, and the fluid is supplied to the flow path 35 in the grindstone shaft 33 through the supply path 30. An opening and closing valve 29 is inserted into the supply path 30. A heating device 37 heats the fluid flowing through the supply path 30.

[0039] The heating device 37 is not operated when the rough processing is performed, and the heating device 37 is operated to supply the heated fluid to the contact surface between the grindstone 10 and the processing object 50 when the finish processing is performed.

[0040] Next, an excellent effect of the second example will be described.

[0041] In the second example, as in the first example, the temperature of the contact surface between the grindstone 10 and the processing object 50 can be adjusted. As a result, the rough processing at a high processing speed and the finish processing with low damage can be performed at a high efficiency.

THIRD EXAMPLE

[0042] Next, a processing device according to a third example will be described with reference to FIGS. 6A and 6B. Hereinafter, a description of a configuration common to the processing device and the processing method according to the first example described with reference to FIGS. 1 to 4 will be omitted.

[0043] FIG. 6A is a schematic cross-sectional view (a partial schematic view) of a processing device according to a third example, and FIG. 6B is a bottom view of a grindstone flange 31. The cross-sectional view taken along a one-dot chain line 6A-6A of FIG. 6B corresponds to FIG. 6A.

[0044] In the first example (FIGS. 3A and 3B), the columnar grindstone 10 having a through-hole provided at the center is used. However, in the third example, a block-type grindstone 10 is used. The plurality of grindstones 10 curved to follow the side surface of the column are disposed at equal intervals in the circumferential direction slightly inside an edge of the lower surface of the grindstone flange 31. The plurality of grindstones 10 are disposed to follow one columnar surface as a whole. An outflow port 35A is provided slightly on the inner peripheral side from the position where the grindstone 10 is disposed. The fluid supplied to the flat plate-shaped flow path in the grindstone flange 31 flows out from the outflow port 35A and is supplied to the contact surface between the grindstone 10 and the processing object 50.

[0045] Next, an excellent effect of the third example will be described.

[0046] In the third example, as in the first example, the temperature of the contact surface between the grindstone 10 and the processing object 50 can be adjusted. As a result, the rough processing at a high processing speed and the finish processing with low damage can be performed at a high efficiency.

[0047] It goes without saying that each of the examples described above is exemplary and the configurations illustrated in different examples can be partially replaced or combined. The same operation and effects due to the same configuration of a plurality of examples are not described sequentially for each example. Furthermore, the present invention is not limited to the examples described above. For example, it will be obvious to those skilled in the art that various changes, improvements, combinations, or the like can be made.

[0048] It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.