Grinding wheel replacing grinding with cutting

Abstract

A grinding wheel replacing grinding with cutting comprises a base and at least ten or more diamond cutting units, the diamond cutting units are arranged on an outer ring portion of the base and arranged in the circumferential direction of the base, each diamond cutting unit comprises two or more diamond blades, the diamond blades are arranged in the circumferential direction of the base, and the diamond blades are arranged in the circumferential direction of the base. The diamond cutting units are arranged on the base and extend in the radial direction of the base, and in each diamond cutting unit, the difference between the highest vertexes of the diamond blades does not exceed 100 micrometers.

Description

Technical Field

[0001] This invention relates to a diamond cutting tool, and more particularly to a grinding wheel that uses cutting instead of grinding. Background Technology

[0002] Single-crystal silicon wafers and third-generation semiconductor (silicon carbide or gallium nitride) wafers are hard and brittle. They are typically planarized using grinding wheels made of diamond abrasive grains, followed by polishing to reduce surface roughness. In other words, current technology employs a segmented method for wafer grinding. Related technologies can be found in US Patent Nos. US10639761B2, US10076825B2, and US8025556B2, among others.

[0003] The abrasive grains of the grinding wheel are approximately in the micrometer range, which limits the amount of material that can be removed from the wafer surface. Therefore, high-speed processing (e.g., greater than 3000 rpm) is necessary. However, at high speeds, diamond abrasive grains can easily detach from the grinding wheel and scratch the wafer surface, affecting its flatness. Furthermore, to avoid cracks on the wafer surface and increase product yield, multiple surface treatments are required to achieve a nanometer-level surface roughness, which is extremely time-consuming.

[0004] Therefore, how to improve the defects of known grinding wheels, which require multiple surface processing steps, are time-consuming and easily affect the flatness of the wafer surface due to abrasive grain shedding, is a problem that those skilled in the art want to solve. Summary of the Invention

[0005] The main objective of this invention is to solve the problem that known grinding wheels consume a lot of time when grinding wafers, and the detached abrasive grains can easily scratch deep marks on the wafer surface.

[0006] To address the aforementioned problems, the present invention provides a grinding wheel that replaces grinding with cutting, comprising: a base and at least ten diamond cutting units, wherein the diamond cutting units are disposed on an outer ring portion of the base and arranged along the circumferential direction of the base, each diamond cutting unit comprising two or more diamond blades, the diamond blades being arranged along the circumferential direction of the base and extending radially along the base, wherein the difference between the highest apexes of the diamond blades in each diamond cutting unit does not exceed 100 micrometers.

[0007] In one embodiment, in the diamond cutting unit, the diamond blade includes a first blade and a second blade, the first blade being a monocrystalline diamond and the second blade being a polycrystalline diamond.

[0008] In one embodiment, in the diamond cutting unit, each of the diamond cutting blades is identical, and the diamond cutting blade is a single crystal diamond or a polycrystalline diamond.

[0009] In one embodiment, the diamond blade comprises polycrystalline diamond with a particle size between 1 micrometer and 100 micrometers.

[0010] In one embodiment, the grinding wheel is used to process a workpiece, which is a wafer or a regenerated wafer.

[0011] In one embodiment, the feed rate of the grinding wheel during processing is between 0.1 micrometers per second and 1 micrometer per second, and the rotational speed is between 1000 RPM and 10000 RPM.

[0012] In one embodiment, the grinding wheel is used to thin a wafer to a thickness of less than 100 micrometers.

[0013] In one embodiment, the tip of each diamond blade includes a tapered ridge portion, the width of which is between 10 micrometers and 1000 micrometers.

[0014] In one embodiment, the diamond blade includes a blade body and a cutting layer disposed on the blade body, the cutting layer being a polycrystalline diamond or a monocrystalline diamond sintered from diamond microparticles.

[0015] In one embodiment, the cutting angle of the diamond blade is between 80 and 110 degrees. Attached Figure Description

[0016] Figure 1 This is a top view schematic diagram of an embodiment of the present invention.

[0017] Figure 2 This is a side view schematic diagram of an embodiment of the present invention.

[0018] Figure 3 This is a partially enlarged view of a diamond cutting unit according to an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of a diamond cutting unit according to another embodiment of the present invention.

[0020] Figure 5A for Figure 4 A side view diagram.

[0021] Figure 5B for Figure 5A A partially enlarged schematic diagram. Detailed Implementation

[0022] The terminology used herein is for the purpose of illustrating particular embodiments only and is not intended to limit the invention. Unless the context otherwise indicates, the singular forms “a” and “the” used herein may also include the plural forms.

[0023] The directional terms used herein, such as up, down, left, right, front, back, and their derivatives or synonyms, refer to the orientation of elements in the accompanying drawings and are not intended to limit the invention, unless the context clearly states otherwise.

[0024] See Figure 1 , Figure 2 This invention discloses a grinding wheel 1 that replaces grinding with cutting, which can be used to process non-metallic ceramic materials. The grinding wheel 1 includes a base 10 and a plurality of diamond cutting units 20. In this embodiment, the grinding wheel 1 includes at least ten diamond cutting units 20. The grinding wheel 1 is used to process a workpiece, which is a wafer or a regenerated wafer, and the workpiece is silicon, silicon carbide or gallium oxide.

[0025] The base 10 includes a central portion 11 and an outer ring portion 12, and has a circumferential direction 10a and a radial direction. The diamond cutting unit 20 is disposed on the outer ring portion 12 and arranged along the circumferential direction 10a of the base 10. The diamond cutting unit 20 protrudes from a base surface 13 of the base 10. In this example, there are 36 diamond cutting units 20, which are arranged at equal intervals along the circumferential direction 10a, and the gap G between each diamond cutting unit 20 is 5 mm.

[0026] See Figure 3 The diamond cutting unit 20 includes a plurality of diamond blades 21 arranged along the circumferential direction 10a of the base 10 and extending radially along the base 10. In each diamond cutting unit 20, the difference between the highest apexes of the diamond blades 21 does not exceed 100 micrometers, preferably less than 20 micrometers. In this embodiment, the diamond cutting unit 20 includes two or more diamond blades 21.

[0027] Each diamond cutting tool 21 includes a tool body 211 and a cutting layer 212. The cutting layer 212 is disposed on the tool body 211 and located at the top end 211a of the tool body 211. The cutting layer 212 includes a tapered ridge portion 213, which has a chamfer 2131 and a chip escape angle 2132.

[0028] In this embodiment, the thickness t of the diamond cutting blade 21 is between 1 mm and 3 mm, preferably 2 mm; the width w of the diamond cutting blade 21 is between 2 mm and 4 mm, preferably 3 mm; and the depth d of the diamond cutting blade 21 is greater than 3 mm. The thickness t1 of the cutting layer 212 is between 0.25 mm and 1 mm, preferably 0.5 mm. The width of the ridge portion 213 is between 10 micrometers and 1000 micrometers; and the cutting angle θ1 of the diamond cutting blade 21 is between 80 degrees and 110 degrees. The chip escape angle θ2 of the chip escape angle 2132 is 5 degrees.

[0029] In one example, the cutting angle and feed rate of the diamond insert 21 do not exceed the plastic deformation zone of the workpiece to be machined.

[0030] The diamond cutting unit 20 may include multiple diamond blades 21, which may comprise monocrystalline or polycrystalline diamonds, and each of the diamond blades 21 may be identical or different. This embodiment, for example... Figure 3 As shown, a single diamond cutting unit 20 has four diamond cutting blades 21, which, from left to right, are a first blade 21a, a second blade 21b, a third blade 21c, and a fourth blade 21d. The cutting layer 212 of the first blade 21a is monocrystalline diamond, while the cutting layer 212 of the second blade 21b, third blade 21c, and fourth blade 21d is polycrystalline diamond. The polycrystalline diamond has a particle size between 1 micrometer and 100 micrometers and is formed by sintering diamond microparticles. The first blade 21a, second blade 21b, third blade 21c, and fourth blade 21d are arranged sequentially from low to high based on their height protruding upwards from the base surface 13, with a height difference of less than 10 micrometers. In one example, the volume percentage of diamond in the diamond cutting blade 21 is at least 30%.

[0031] In one example, the cutting layer 212 of the first blade 21a is a single-crystal diamond, the cutting layer 212 of the second blade 21b is formed by sintering polycrystalline diamond powder with a particle size of 2 micrometers, the cutting layer 212 of the third blade 21c is formed by sintering polycrystalline diamond powder with a particle size of 10 micrometers, and the cutting layer 212 of the fourth blade 21d is formed by sintering polycrystalline diamond powder with a particle size of 25 micrometers. When machining the workpiece, the surface of the workpiece is sequentially machined by the fourth blade 21d, the third blade 21c, the second blade 21b, and the first blade 21a.

[0032] In a practical machining example, the feed rate of the grinding wheel 1 during machining is between 0.1 micrometers per second and 5 micrometers per second. For example, machining is performed at a feed rate of 5 micrometers per second in the first minute, at a feed rate of 3 micrometers per second in the second minute, and at a feed rate of 1 micrometer per second in the last half minute. The rotational speed of the grinding wheel 1 is between 1000 RPM and 10000 RPM, for example, 3500 RPM, in order to thin the workpiece to a thickness of less than 100 micrometers.

[0033] Figure 4A diamond cutting unit 30, as shown in another embodiment, includes a plurality of diamond blades 31, which are horizontally arranged thick-cutting serrations. The diamond blades 31, from left to right, are a first blade 31a, a second blade 31b, a third blade 31c, and a fourth blade 31d. In one example, the cutting layer 312 of the first blade 31a, the second blade 31b, the third blade 31c, and the fourth blade 31d is monocrystalline diamond; while in another example, the cutting layer 312 of the first blade 31a, the second blade 31b, the third blade 31c, and the fourth blade 31d is polycrystalline diamond. The blade body 311 of the diamond blade 31 is made of tungsten carbide or cobalt metal. The particle size of the polycrystalline diamond is between 1 micrometer and 100 micrometers and is formed by sintering diamond micropowder. In one example, the tip height of the first blade 31a is lower than that of the second blade 31b, the tip height of the second blade 31b is lower than that of the third blade 31c, and the tip height of the third blade 31c is lower than that of the fourth blade 31d.

[0034] In this embodiment, the thickness t of the diamond cutting blade 31 is between 1 mm and 3 mm, preferably 2 mm; the width w of the diamond cutting blade 31 is between 2 mm and 4 mm, preferably 3 mm; and the depth d of the diamond cutting blade 31 is greater than 3 mm. The thickness t1 of the cutting layer 312 is between 0.25 mm and 1 mm, preferably 0.5 mm. The width w1 of the edge portion 313 of the diamond cutting blade 31 is between 10 micrometers and 1000 micrometers; the cutting edge angle of the diamond cutting blade 31 is between 80 degrees and 110 degrees; and the chip escape angle of the diamond cutting blade 31 is 5 degrees.

[0035] Figure 5A show Figure 4 The side view, and Figure 5B for Figure 5A The enlarged schematic diagram shows the features of the edge portion 313, which includes a first arc segment 313a, a platform segment 313b, and a second arc segment 313c, forming a shallow circle. The non-sharp or sharp arc surface is formed at the front and rear ends of the edge portion 313 to avoid chipping during wafer insertion.

[0036] One aspect of the present invention relates to a processing method, which utilizes Figures 4 to 5B The diamond cutting unit 30 shown has 32 blades, which are bonded to the circumference of a grinding wheel using epoxy resin. The right-angled side of the diamond cutting blade 31 of the diamond cutting unit 30 faces the direction of rotation. Figure 4 In this process, a counter-clockwise rotation is applied at a speed of 3000 RPM to 4000 RPM, for example, about 3500 RPM, to process silicon wafers or semiconductor wafers of other materials.

[0037] In summary, this invention provides multiple diamond cutting units mounted on the base, replacing traditional grinding wheels made of diamond abrasive grains with grinding wheels equipped with multiple diamond blades. This not only prevents abrasive grains from detaching and affecting the flatness of the workpiece (wafer) surface, but also increases removal efficiency. Furthermore, by mounting multiple diamond blades on the base, the surface of the workpiece to be polished can be used as a reference for mounting the diamond blades, or the blade edges can be ground flat after mounting to make the apexes of the diamond blades flush, which is beneficial for the flattening of the workpiece surface. On the other hand, the diamond cutting units on the base can use the same grinding disc by combining different diamond blades, eliminating the need to change grinding wheels of various abrasive sizes for multiple processing operations as in known methods. This not only saves processing time but also reduces the cost of the manufacturing process.

[0038] Furthermore, this invention can replace existing multi-segment wafer grinding and can be applied to, but is not limited to, silicon wafers, silicon carbide wafers, gallium oxide (Ga2O3) wafers, etc.

[0039] [Symbol Explanation]

[0040] 1: Grinding wheel

[0041] 10: Base

[0042] 10a: Circumferential direction

[0043] 11: Central Part

[0044] 12: Outer Ring Section

[0045] 13: Base plane

[0046] 20: Diamond Cutting Unit

[0047] 21: Diamond Blade

[0048] 21a: First blade

[0049] 21b: Second blade

[0050] 21c: Third blade

[0051] 21d: Fourth Blade

[0052] 211: Blade Body

[0053] 211a: Top

[0054] 212: Cutting layer

[0055] 213: Edge section

[0056] 2131: Chamfer

[0057] 2132: Escape Corner

[0058] 30: Diamond Cutting Unit

[0059] 31: Diamond Blade

[0060] 31a: First blade

[0061] 31b: Second blade

[0062] 31c: Third blade

[0063] 31d: Fourth blade

[0064] 311: Blade Body

[0065] 312: Cutting layer

[0066] 313: Edge section

[0067] 313a: An arc-shaped segment

[0068] 313b: Platform segment

[0069] 313c: Second arc segment

[0070] G: Gap

[0071] t: thickness

[0072] w: width

[0073] w1: Width

[0074] d: Depth

[0075] t1: Thickness

[0076] θ1: Cutting edge angle

[0077] θ2: Angle

Claims

1. A grinding wheel that replaces grinding with cutting, characterized in that, include: A base; as well as At least ten diamond cutting units are disposed on an outer ring portion of the base and arranged along the circumferential direction of the base. Each diamond cutting unit includes two or more diamond blades arranged along the circumferential direction of the base and extending radially along the base. In each diamond cutting unit, the difference between the highest apexes of the diamond blades does not exceed 100 micrometers.

2. The grinding wheel according to claim 1, characterized in that, In the diamond cutting unit, the diamond blade includes a first blade and a second blade, wherein the first blade is a monocrystalline diamond and the second blade is a polycrystalline diamond.

3. The grinding wheel according to claim 1, characterized in that, In the diamond cutting unit, all the diamond cutting blades are identical, and the diamond cutting blades are either single-crystal diamonds or polycrystalline diamonds.

4. The grinding wheel according to claim 1, characterized in that, The diamond blade comprises polycrystalline diamonds with a particle size between 1 micrometer and 100 micrometers.

5. The grinding wheel according to claim 1, characterized in that, The grinding wheel is used to process a workpiece, which is a wafer or a regenerated wafer.

6. The grinding wheel according to claim 1, characterized in that, The feed rate of the grinding wheel during processing is between 0.1 micrometers per second and 1 micrometer per second, and the rotational speed is between 1000 RPM and 10000 RPM.

7. The grinding wheel according to claim 1, characterized in that, The grinding wheel is used to thin the wafer to a thickness of less than 100 micrometers.

8. The grinding wheel according to claim 1, characterized in that, The tip of each of the diamond blades includes a tapered ridge portion, the width of which is between 10 micrometers and 1000 micrometers.

9. The grinding wheel according to claim 1, characterized in that, The diamond blade includes a blade body and a cutting layer disposed on the blade body, wherein the cutting layer is a polycrystalline diamond or a single-crystal diamond formed by sintering diamond microparticles.

10. The grinding wheel according to claim 1, characterized in that, The cutting angle of the diamond blade is between 80 and 110 degrees.

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