Crystal ingot polishing grinding wheel

Abstract

The invention provides a crystal ingot polishing grinding wheel which comprises a basic unit which comprises a wheel-shaped body and a polishing layer, and a shaft hole is formed in the axis of the wheel-shaped body. The wheel-shaped body is provided with an extension part which is formed by extending outwards in the radial direction, the extension part is provided with two annular extension convex parts and an annular extension concave part, and the annular extension concave part is formed by being concaved inwards towards the shaft hole relative to the two annular extension convex parts; the polishing layer is provided with two first working parts and a second working part; the two first working parts are arranged on the surfaces of the two annular extending convex parts, and the second working parts are arranged on the surfaces of the annular extending concave parts. The crystal ingot polishing grinding wheel has the effects of being easy to operate and high in convenience, and can solve the problems of subsurface damage, high surface roughness and the like after wafer edge grinding.

Description

Technical Field

[0001] The present invention relates to a grinding wheel, in particular to a crystal ingot polishing grinding wheel, which can be used in the process of manufacturing semiconductor wafers. Background Art

[0002] Common electronic products like mobile phones, computers, and digital cameras rely on the diverse designs of their integrated circuits (ICs), enabling them to achieve a wide range of performance and functionality. In the IC manufacturing process, semiconductor wafers serve as the substrate upon which electronic components like transistors and diodes are mounted. The research, development, and improvement of these processes have always been a focus of industry attention.

[0003] Generally speaking, semiconductor wafers are manufactured by first forming a semiconductor material (such as silicon (Si) or silicon carbide (SiC)) into a cylindrical semiconductor ingot with a single crystal structure. The ingot is then cut radially with a wire saw according to the desired wafer thickness to obtain multiple disc-shaped wafers. The wafers are then ground (for example, using a grinding wheel) to flatten their surfaces. Finally, the ground wafers are polished (for example, using a polishing tape or pad in combination with a polishing solution) to achieve a mirror-like finish. The wafer edge is first shaped with a grinding wheel before being polished to remove stress or damage.

[0004] However, since the side surface of the semiconductor crystal ingot is curved, it is prone to slippage and shaking when cut with a wire saw, resulting in the wafer surface being too rough and uneven in thickness, especially at the edge of the wafer. To address this problem, a patent application in Taiwan, China with publication number TW202316510A has proposed a method for manufacturing semiconductor wafers, which includes first performing a groove processing step on the curved side surface of the semiconductor crystal ingot with a grinding wheel (or called a grooving wheel) (for example, using a blade or protrusion on a diamond grinding wheel for grooving), so that a plurality of indentations (or called grooves, depressions) are generated on the curved side surface of the semiconductor crystal ingot, thereby providing positioning and guiding effects during subsequent wire saw cutting and avoiding the problem of wire saw slippage and shaking. However, the aforementioned groove processing step using a grinding wheel is prone to causing subsurface damage to the semiconductor ingot and still suffers from the problem of high surface roughness. This makes the edges of the wafers obtained by wire sawing prone to defects such as micro-chipping, particle accumulation, and metal ion residue. These defects seriously affect subsequent processes and may even require the entire wafer to be scrapped due to severe defects, which not only increases costs but also wastes resources.

[0005] To address the aforementioned issues of subsurface damage and high surface roughness on the edges of semiconductor ingots or wafers, polishing methods typically employ either polishing tapes or polishing pads in conjunction with polishing slurries. For silicon, polishing to reduce the surface arithmetic average roughness (Ra) to below approximately 3 nanometers (nm) solves these problems. For silicon carbide, polishing to reduce the surface arithmetic average roughness (Ra) to below approximately 1.5 nm solves these problems. However, polishing tapes and polishing pads are both soft materials and difficult to control in shape, making their operation more difficult and complex, and thus less convenient.

[0006] Meanwhile, Taiwan's patent application, publication number TWM444244U1, discloses a grinding wheel for shaping memory cards. The grinding wheel features an abrasive layer designed specifically for the specific shape required for memory cards (also known as SD cards (secure digital cards)). The grinding layer is then used to grind the memory card to achieve the unique shape unique to the memory card. This allows the resulting memory card to have a more flat surface, while also improving the strength and lifespan of the grinding wheel. However, the aforementioned semiconductor ingot and memory card are completely different in terms of shape, material, subsequent manufacturing processes, application, and technical fields. Furthermore, TWM444244U1 achieves this shaping by grinding the memory card with the abrasive layer, rather than providing further surface treatment on the already shaped memory card. Therefore, the technical content disclosed in TWM444244U1 clearly fails to provide a solution to the technical issues of subsurface damage and high surface roughness caused by the groove processing step using the grinding wheel.

[0007] Therefore, it can be seen that new technical solutions are still to be found and researched, which can perform polishing without using soft polishing belts or polishing pads to solve problems such as sub-surface damage and high surface roughness at the edges of semiconductor ingots or wafers, thereby improving the quality of subsequently produced wafers. Summary of the Invention

[0008] In view of the defects of the prior art, the purpose of the present invention is to provide a crystal ingot polishing grinding wheel, which has a structural design corresponding to the shape of the side surface of the grooved semiconductor crystal ingot, thereby avoiding the disadvantages of the prior art of using polishing belts or polishing pads made of soft materials for polishing, which are difficult to control, and can also solve the problems of sub-surface damage and high surface roughness on the edges of semiconductor crystal ingots or wafers.

[0009] To achieve the aforementioned objectives, the present invention provides a crystal ingot polishing grinding wheel, which comprises: a basic unit, which comprises: a wheel-shaped body, an axial hole is provided at the axis center of the wheel-shaped body; the wheel-shaped body has an extension portion extending radially outward, the extension portion has two annular extension protrusions and an annular extension recess, and the annular extension recess is arranged between the two annular extension protrusions, and the annular extension recess is concavely formed toward the axial hole relative to the two annular extension protrusions; and a polishing layer, the polishing layer has two first working portions and a second working portion, and the polishing layer is formed on the surface of the extension portion; wherein the two first working portions are arranged on the surface of the two annular extension protrusions, and the second working portion is arranged on the surface of the annular extension recess; the shape and width of the two first working portions correspond to the shape and width of the indentation formed by grooving the arcuate side surface of a semiconductor crystal ingot, and the shape and width of the second working portion correspond to the shape and width of the protrusion formed by grooving the arcuate side surface of the semiconductor crystal ingot.

[0010] By controlling the extension portion on the wheel-shaped body to form the two annular extension convex portions and the annular extension concave portion, and then forming the polishing layer on the surface of the extension portion to constitute the two first working portions and the second working portion which can respectively correspond to the indentations and convex portions on the curved side surface of the semiconductor crystal ingot, the crystal ingot polishing wheel of the present invention uses a hard and fixed-shape material to polish the semiconductor crystal ingot, thereby avoiding the disadvantage of the prior art of using soft materials for polishing and having the disadvantage of being difficult to control. That is, the crystal ingot polishing wheel of the present invention has the advantages of simple operation and high convenience, and can also solve the problems of sub-surface damage and high surface roughness of the edge of the semiconductor crystal ingot or wafer.

[0011] In some embodiments of the present invention, the polishing layer is formed on the surface of the extension portion by vapor deposition or electrochemical deposition (also known as electroplating). Specifically, vapor deposition includes chemical vapor deposition (CVD) or physical vapor deposition (PVD). In other embodiments of the present invention, the polishing layer is formed on the surface of the extension portion by chemical vapor deposition, sputtering, or electrochemical deposition.

[0012] According to the present invention, the material of the polishing layer is not particularly limited. Those skilled in the art may select and adjust the material based on actual needs without affecting the effectiveness of the present invention. In some embodiments of the present invention, the polishing layer may be made of a rigid material or a soft material. The rigid material includes diamond (including single crystal, polycrystalline, or amorphous), diamond-like carbon (DLC), silicon carbide, metal nitrides (such as titanium nitride (TiN)), metal carbides, metal oxides (such as zirconium dioxide (ZrO2) or aluminum oxide (Al2O3)), rigid resins, or combinations thereof. The soft material includes soft resins, rubber, or combinations thereof.

[0013] In some embodiments of the present invention, the thickness of the polishing layer is greater than 1 micrometer (μm) and less than 1 centimeter (cm). In other embodiments of the present invention, the thickness of the polishing layer is greater than or equal to 20 μm and less than or equal to 500 μm.

[0014] According to the present invention, “the annular extending recess is concavely formed inwardly toward the axial hole relative to the two annular extending protrusions” means that the surface of the annular extending recess is concavely formed inwardly toward the axial hole relative to the surfaces of the two annular extending protrusions.

[0015] In some embodiments of the present invention, the ingot polishing grinding wheel is composed of a single basic unit (i.e., a single-blade grinding wheel), and the widths of the two first working portions are independently 52.5 μm to 975 μm; in other embodiments of the present invention, the widths of the two first working portions are independently 52.5 μm to 750 μm; in other embodiments of the present invention, the widths of the two first working portions are independently 52.5 μm to 650 μm; in other embodiments of the present invention, the widths of the two first working portions are independently 52.5 μm to 600 μm; in other embodiments of the present invention, the widths of the two first working portions are independently In some other embodiments of the present invention, the width of the two first working portions is independently 150 μm to 575 μm; in some other embodiments of the present invention, the width of the two first working portions is independently 150 μm to 300 μm; in some other embodiments of the present invention, the width of the two first working portions is independently 155 μm to 300 μm; in some other embodiments of the present invention, the width of the two first working portions is independently 155 μm to 250 μm; in some other embodiments of the present invention, the width of the two first working portions is independently 155 μm to 200 μm.

[0016] According to the present invention, the grooves formed by grooving the curved side surface of the semiconductor ingot allow a wire saw to be inserted therein to cut the semiconductor ingot and obtain wafers. Therefore, when the ingot polishing wheel is composed of a single basic unit, the width of the first working portion can correspond to the diameter of the wire saw. The diameter of the wire saw can be 50μm to 500μm, for example, 80μm, 100μm, 150μm, 160μm, 200μm, 250μm, or 300μm, but is not limited thereto. In some embodiments of the present invention, the width of the first working portion can be greater than or equal to 1.05 times the diameter of the wire saw and less than or equal to 1.95 times the diameter of the wire saw, but is not limited thereto. It should be understood that if the wire saw uses piano wire, diamond wire with diamond grit, piano wire wound with multiple strands of wire, or diamond wire wound with multiple strands of wire, the diameter of the wire saw is the diameter of the wire; and if the wire saw uses a saw blade, the diameter of the wire saw refers to the width of the cutting surface of the saw blade.

[0017] In some embodiments of the present invention, the width of the second working portion may be the distance between top ends of two side wall surfaces of the polishing layer on the annular extending recess.

[0018] In some embodiments of the present invention, the width of the second working portion is 50 μm to 1000 μm. In other embodiments of the present invention, the width of the second working portion is 100 μm to 975 μm. In other embodiments of the present invention, the width of the second working portion is 350 μm to 975 μm. In other embodiments of the present invention, the width of the second working portion is 800 μm to 975 μm. In other embodiments of the present invention, the width of the second working portion is 300 μm to 500 μm.

[0019] According to the present invention, the convex portion formed by the grooves on the curved side surface of the semiconductor ingot corresponds to the thickness of the wafer subsequently cut from the semiconductor ingot, so the width of the second working portion can correspond to the thickness of the wafer cut from the semiconductor ingot. The thickness of the wafer can be 50μm to 1000μm, for example: 100μm, 150μm, 300μm, 400μm, 450μm, 500μm, 700μm, 800μm, 850μm, 900μm, 925μm or 975μm, but is not limited thereto. In some embodiments of the present invention, the wafer can be a 12-inch silicon wafer (with a thickness of approximately 925μm) or a 6-inch silicon carbide wafer (with a thickness of approximately 450μm), but is not limited thereto.

[0020] In some embodiments of the present invention, the ingot polishing wheel is composed of a single basic unit, and the ratio between the width of each first working part and the width of the second working part may be 1:0.05 to 1:20; in other embodiments of the present invention, the ratio between the width of each first working part and the width of the second working part may be 1:0.1 to 1:20; in other embodiments of the present invention, the ratio between the width of each first working part and the width of the second working part may be 1:1 to 1:10; in other embodiments of the present invention, the ratio between the width of each first working part and the width of the second working part may be 1:1 to 1:5; in other embodiments of the present invention, the ratio between the width of each first working part and the width of the second working part may be 1:2.5 to 1:5; in other embodiments of the present invention, the ratio between the width of each first working part and the width of the second working part may be 975:50 to 52.5:1000, but is not limited thereto.

[0021] According to the present invention, the shape of the second working portion can correspond to the shape of the protrusion on the curved side surface of the grooved semiconductor ingot (i.e., the shape of the wafer edge that will be subsequently cut). Therefore, the shape of the second working portion is not particularly limited. Those skilled in the art can select and adjust the shape of the second working portion based on the shape of the protrusion or wafer edge without affecting the effectiveness of the present invention. For example, the shape of the second working portion can be a circular arc shape (also known as an R-type shape) that can correspond to the shape of the protrusion or wafer edge; or the shape of the second working portion can be a flat shape (also known as an F-type shape) that can correspond to the shape of the protrusion or wafer edge, but the present invention is not limited thereto.

[0022] In some embodiments of the present invention, the shape of the second working portion is an arc shape corresponding to the shape of the protrusion or the edge of the wafer, and the arc shape can be composed of a single curvature; or can be composed of two or more curvatures.

[0023] In some embodiments of the present invention, the extension portion further includes two shape-changing portions, formed by radially outward extensions of the two annular extending protrusions. In an axial cross-section of the wheel-shaped body, the top ends of the two shape-changing portions each independently have an acute angle, an arc, an obtuse angle, or a polygon. It should be understood that each first working portion refers to the polishing layer formed on the surface of each shape-changing portion and the corresponding annular extending protrusion.

[0024] In some embodiments of the present invention, the ingot polishing wheel is composed of a single basic unit, and the thickness of the two shape-changing portions is independently 0.5 to 5 times the width of the corresponding first working portion.

[0025] In some embodiments of the present invention, the ingot polishing wheel further includes a functional layer disposed between the surface of the extension portion and the polishing layer. The functional layer can be selected and adjusted by those skilled in the art based on actual needs without affecting the efficacy of the present invention. For example, the functional layer can be a coating buffer layer or an adhesion strengthening layer, but is not limited thereto. Those skilled in the art can select an appropriate material based on the desired function or characteristic. In some embodiments of the present invention, the material of the functional layer can be a metal (e.g., titanium (Ti)), a metal nitride (e.g., TiN), or a metal carbide (e.g., titanium carbide (TiC)).

[0026] In some embodiments of the present invention, the thickness of the functional layer is greater than 0.5 μm and less than 0.5 cm. In other embodiments of the present invention, the thickness of the functional layer is greater than or equal to 1 μm and less than or equal to 10 μm.

[0027] According to the present invention, the material of the wheel-shaped body is not particularly limited. Those skilled in the art may select and adjust the material based on actual needs without affecting the effectiveness of the present invention. In some embodiments of the present invention, the material of the wheel-shaped body may include a metal material (e.g., stainless steel), a resin (e.g., epoxy resin), a fiber material (e.g., carbon fiber or glass fiber), a carbide (e.g., tungsten carbide), or a ceramic material.

[0028] In addition, the present invention also provides a crystal ingot polishing grinding wheel, which includes a plurality of basic units, and each basic unit is arranged axially and side by side; each basic unit includes: a wheel-shaped body, the axis of the wheel-shaped body is provided with an axial hole; the wheel-shaped body has an extension portion extending radially outward, the extension portion has two annular extension protrusions and an annular extension concave portion, and the annular extension concave portion is arranged between the two annular extension protrusions, and the annular extension concave portion is concavely formed toward the axial hole relative to the two annular extension protrusions; and a polishing layer, the polishing layer has two first working portions and a second working portion. working part, and the polishing layer is formed on the surface of the extension part; wherein the two first working parts are arranged on the surfaces of the two annular extension convex parts, and the second working part is arranged on the surface of the annular extension concave part; the two first working parts connected and merged in adjacent basic units constitute a merged first working part, the shape and width of the merged first working part correspond to the shape and width of the indentation formed by grooving on the arcuate side surface of a semiconductor crystal ingot, and the shape and width of the second working part correspond to the shape and width of the convex part formed by grooving on the arcuate side surface of the semiconductor crystal ingot.

[0029] In some embodiments of the present invention, the ingot polishing grinding wheel is composed of the plurality of basic units (i.e., a multi-blade grinding wheel), and the widths of the merged first working portions are independently 52.5 μm to 975 μm; in other embodiments of the present invention, the widths of the merged first working portions are independently 52.5 μm to 750 μm; in other embodiments of the present invention, the widths of the merged first working portions are independently 52.5 μm to 650 μm; in other embodiments of the present invention, the widths of the merged first working portions are independently 52.5 μm to 600 μm; in other embodiments of the present invention, the widths of the merged first working portions are independently In some embodiments of the present invention, the width of the combined first working portion is independently 52.5 μm to 575 μm; in some other embodiments of the present invention, the width of the combined first working portion is independently 150 μm to 575 μm; in some other embodiments of the present invention, the width of the combined first working portion is independently 150 μm to 300 μm; in some other embodiments of the present invention, the width of the combined first working portion is independently 155 μm to 300 μm; in some other embodiments of the present invention, the width of the combined first working portion is independently 155 μm to 250 μm; in some other embodiments of the present invention, the width of the combined first working portion is independently 155 μm to 200 μm. In addition, the width of the combined first working portion may be greater than or equal to 1.05 times the diameter of the wire saw and less than or equal to 1.95 times the diameter of the wire saw, but is not limited thereto.

[0030] In some embodiments of the present invention, the ingot polishing wheel is composed of the multiple basic units, and the sum of the widths of the two first working parts connected and merged in adjacent basic units is the width of the merged first working part; in other embodiments of the present invention, the width of the two first working parts connected and merged in adjacent basic units is half the width of the merged first working part.

[0031] In some embodiments of the present invention, the ingot polishing wheel is composed of the multiple basic units, and the ratio between the width of each merged first working part and the width of the second working part may be 1:0.05 to 1:20; in other embodiments of the present invention, the ratio between the width of each merged first working part and the width of the second working part may be 1:0.1 to 1:20; in other embodiments of the present invention, the ratio between the width of each merged first working part and the width of the second working part may be 1:1 to 1:10; in other embodiments of the present invention, the ratio between the width of each merged first working part and the width of the second working part may be 1:1 to 1:5; in other embodiments of the present invention, the ratio between the width of each merged first working part and the width of the second working part may be 1:2.5 to 1:5; in other embodiments of the present invention, the ratio between the width of each merged first working part and the width of the second working part may be 975:50 to 52.5:1000, but is not limited thereto.

[0032] In some embodiments of the present invention, the ingot polishing grinding wheel is composed of the plurality of basic units, and the thickness of each of the shape-changing portions is independently 0.5 to 5 times the width of the corresponding combined first working portion.

[0033] In some embodiments of the present invention, the ingot polishing wheel is composed of the multiple basic units, and the combination of the multiple basic units is assembled into one body through the axial hole; or the combination of the multiple basic units is formed into one body.

[0034] In this specification, a range expressed as "from a smaller value to a larger value" unless otherwise specified indicates that the range is greater than or equal to the smaller value and less than or equal to the larger value. For example, "52.5 μm to 975 μm" means the range is "greater than or equal to 52.5 μm and less than or equal to 975 μm." BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagrams of the appearance of some embodiments of the ingot polishing wheel of the present invention.

[0036] Figure 2 1 and 2 are side views of some embodiments of the ingot polishing grinding wheel of the present invention.

[0037] Figure 3 1 and 2 are axial cross-sectional views of some embodiments of the ingot polishing grinding wheel of the present invention.

[0038] Figure 4 Schematic diagrams of the appearance of some embodiments of the ingot polishing wheel of the present invention.

[0039] Figure 51 is an axial cross-sectional view near the central area of ​​some embodiments of the ingot polishing grinding wheel of the present invention.

[0040] Figure 6 1 is an axial cross-sectional view near the central area of ​​some embodiments of the ingot polishing grinding wheel of the present invention.

[0041] 7A to 7D 1 and 2 are axial cross-sectional views of different embodiments of the ingot polishing grinding wheel of the present invention near the central area.

[0042] Figure 8 Schematic diagram of polishing the curved side surface of a semiconductor ingot using some embodiments of the ingot polishing grinding wheel of the present invention.

[0043] Figure 9A It is a schematic diagram of the process of manufacturing semiconductor wafers commonly selected in the existing technology.

[0044] Figure 9B The present invention is a schematic diagram of a process for polishing a crystal ingot using the polishing wheel of the present invention.

[0045] Figure 10A and Figure 10B These are the surface roughness results of different groups in Experimental Example 1 when measuring the edge of the wafer or the convex portion of the side surface of the semiconductor ingot.

[0046] Figure 11A and Figure 11B These are optical images of the edges of the convex portions on the side surfaces of semiconductor crystal ingots after polishing the convex portions using the crystal ingot polishing wheels of Example 1 and Example 2, respectively.

[0047] Figures 11C to 11E The optical images are of the wafer edge of an unprocessed wafer cut from a semiconductor ingot, a wafer after the surface of which is further ground with a conventional grinding wheel, and a wafer after the surface of which is further polished with a polishing pad and a polishing liquid. DETAILED DESCRIPTION

[0048] Several embodiments are listed below to illustrate the implementation methods of the present invention. Those skilled in the art can easily understand the advantages and effects that can be achieved by the present invention through the contents of this specification, and make various modifications and changes without departing from the spirit of the present invention to implement or apply the contents of the present invention.

[0049] Please see first Figures 1 to 3 , which is used to illustrate and explain some embodiments of the present invention. Specifically, Figure 1 As shown, the ingot polishing wheel 1 of the present invention is composed of a single basic unit 10, and the basic unit 10 includes a wheel-shaped body 11 and a polishing layer 12. The axis of the wheel-shaped body 11 is provided with an axial hole, and the polishing layer 12 is provided on a rim of the wheel-shaped body 11. Figure 2 As shown, the ingot polishing wheel 1 is sectioned along the axial section auxiliary line AA passing through the center of the circle, and the following is obtained: Figure 3 The axial cross-section of the ingot polishing wheel 1 is shown. Figure 3 In the embodiment, the wheel-shaped body 11 of the basic unit 10 is the wheel-shaped body 11 of the ingot polishing wheel 1, and the polishing layer 12 of the basic unit 10 is the polishing layer 12 of the ingot polishing wheel 1. The wheel-shaped body 11 of the ingot polishing wheel 1 of the present invention has an extension portion 111 extending radially outward. The extension portion 111 has two annular extension protrusions and an annular extension recess. The annular extension recess is disposed between the two annular extension protrusions, and the surface of the annular extension recess is concave inwardly toward the axial hole relative to the surfaces of the two annular extension protrusions. The polishing layer 12 has two first working portions 121 and a second working portion 122, and is formed on the surface of the extension portion 111. Specifically, the two first working portions 121 are disposed on the surfaces of the two annular extension protrusions, and the second working portion 122 is disposed on the surface of the annular extension recess. The shape and width of each first working portion 121 correspond to the shape and width of a recess formed by grooving the curved side surface of a semiconductor ingot, while the shape and width of the second working portion 122 correspond to the shape and width of a protrusion formed by grooving the curved side surface of the semiconductor ingot. The width of the second working portion 122 is 2.5 times the width of the two first working portions 121. Furthermore, the polishing layer 12 is formed on the surface of the extension portion 111 by chemical vapor deposition. Specifically, the two first working portions 121 and the second working portion 122 are also formed by chemical vapor deposition on the surfaces of the two annular extension protrusions and the annular extension recess, respectively.

[0050] See also Figure 4 and Figure 5, which is used to illustrate and describe some embodiments of the present invention. Specifically, the ingot polishing wheel 1 of the present invention is composed of a plurality of basic units 10 arranged axially and close to each other. Each basic unit 10 is defined by adjacent auxiliary dashed lines and includes a wheel-shaped body 11 and a polishing layer 12. The wheel-shaped body 11 has an axial hole defined at its axis, and the polishing layer 12 is disposed on a rim of the wheel-shaped body 11. The polishing layer 12 of the ingot polishing wheel 1 is formed by interconnecting the polishing layers 12 of the plurality of basic units 10, and the wheel-shaped body 11 of the ingot polishing wheel 1 is formed by interconnecting the wheel-shaped body 11 of the plurality of basic units 10. The wheel-shaped body 11 of the ingot polishing wheel 1 has an extension portion 111 extending radially outward. The extension portion 111 has a plurality of annular extending protrusions and a plurality of annular extending recesses, each of which is disposed between two adjacent annular extending protrusions. The surface of each annular extending recess is concave inwardly toward the axial hole relative to the surface of each annular extending protrusion. The polishing layer 12 has a plurality of first working portions 121 and a plurality of second working portions 122, and is formed on the surface of the extension portion 111. Specifically, the plurality of first working portions 121 are disposed on the surface of the plurality of annular extending protrusions, and the plurality of second working portions 122 are disposed on the surface of the plurality of annular extending recesses. The two first working parts 121 connected and merged in adjacent basic units 10 form a merged first working part 121'. The shape and width of the merged first working part 121' correspond to the shape and width of the indentation formed by grooving the curved side surface of a semiconductor crystal ingot. The shape and width of each second working part 122 correspond to the shape and width of the convex part formed by grooving the curved side surface of the semiconductor crystal ingot. The width of each second working part 122 is 2.5 times the width of each merged first working part 121'. It should be understood that in two adjacent basic units 10, the first working part 121 on one basic unit 10 will be connected and merged with the first working part 121 on the other basic unit 10 to form the merged first working part 121', and the sum of the widths of the first working parts 121 on the two adjacent basic units 10 is the width of the merged first working part 121'. Figure 5 The illustrated embodiment is merely an example. The width of each of the two connected and merged first working portions 121 on two adjacent basic units 10 is half the width of the merged first working portion 121'. Furthermore, the polishing layer 12 is formed on the surface of the extension portion 111 by chemical vapor deposition. Specifically, the first working portion 121 and the second working portion 122 are also formed on the surfaces of the annular extension protrusion and the annular extension recess, respectively, by chemical vapor deposition.

[0051] See also Figure 6, which is used to illustrate and describe some embodiments of the present invention. Specifically, the ingot polishing wheel 1 of the present invention is composed of a plurality of basic units 10 arranged axially and close to each other. Each basic unit 10 is defined by adjacent auxiliary dashed lines and includes a wheel-shaped body 11, a polishing layer 12, and a functional layer 13. The wheel-shaped body 11 has an axial hole formed at its axis and has an extension portion 111 extending radially outward. The functional layer 13 is disposed on the surface of the extension portion 111, and the polishing layer 12 is disposed on the surface of the functional layer 13. The continuous layer body formed by the interconnected polishing layers 12 of the multiple basic units 10 is the polishing layer 12 of the ingot polishing wheel 1, the continuous layer body formed by the interconnected functional layers 13 of the multiple basic units 10 is the functional layer 13 of the ingot polishing wheel 1, and the continuous layer body formed by the interconnected wheel-shaped bodies 11 of the multiple basic units 10 is the wheel-shaped body 11 of the ingot polishing wheel 1; wherein, the extension portion 111 has a plurality of annular extension protrusions and a plurality of annular extension recesses, and each annular extension recess is arranged between two adjacent annular extension protrusions, and the surface of each annular extension recess is concave inwardly formed in the direction of the axial hole relative to the surface of each annular extension protrusion; the polishing layer 12 has a plurality of first working portions 121 and a plurality of second working portions 122. Specifically, the plurality of first working portions 121 are disposed on the surface of the functional layer 13 disposed on the plurality of annular extending protrusions, and the plurality of second working portions 122 are disposed on the surface of the functional layer 13 disposed on the plurality of annular extending recesses. Two first working portions 121 connected and merged in adjacent basic units 10 form a merged first working portion 121'. The shape and width of the merged first working portion 121' correspond to the shape and width of a recess formed by grooving the curved side surface of a semiconductor crystal ingot. The shape and width of each second working portion 122 correspond to the shape and width of a protrusion formed by grooving the curved side surface of the semiconductor crystal ingot. The width of each second working portion 122 is 2.5 times the width of each merged first working portion 121'. Furthermore, the functional layer 13 is formed on the surface of the extending portion 111 by chemical vapor deposition, physical vapor deposition, or electrochemical deposition, and the polishing layer 12 is formed on the surface of the functional layer 13 by chemical vapor deposition.

[0052] See also 7A to 7D, which is used to illustrate and describe some embodiments of the present invention. Specifically, the ingot polishing wheel 1 of the present invention is composed of a plurality of basic units 10 arranged axially and close to each other. Each basic unit 10 is defined by adjacent auxiliary dashed lines and includes a wheel-shaped body 11 and a polishing layer 12. The wheel-shaped body 11 has an axial hole defined at its axis, and the polishing layer 12 is disposed on a rim of the wheel-shaped body 11. The polishing layers 12 of the multiple basic units 10 are connected to form a continuous layer, which is the polishing layer 12 of the ingot polishing wheel 1. The wheel-shaped bodies 11 of the multiple basic units 10 are connected to form a continuous layer, which is the wheel-shaped body 11 of the ingot polishing wheel 1. The wheel-shaped body 11 has an extension portion 111 extending radially outward, and the extension portion 111 has a plurality of annular extension protrusions and a plurality of annular extension recesses, and each annular extension recess is arranged between two adjacent annular extension protrusions, and the surface of each annular extension recess is concave inwardly toward the direction of the axial hole relative to the surface of each annular extension protrusion. At the same time, the extension portion 111 also includes a plurality of shape-changing portions 112, each of which is formed by the radial outward extension of the plurality of annular extension protrusions. In the axial cross-section of the wheel-shaped body 11, the shape of the top end of the plurality of shape-changing portions 112 can each be independently arc-shaped (such as Figure 7A As shown), obtuse (as Figure 7B As shown), acute angle (as Figure 7C as shown) or polygonal (as Figure 7D (as shown). The polishing layer 12 has a plurality of first working parts 121 and a plurality of second working parts 122, and the polishing layer 12 is formed on the surface of the extension portion 111. Specifically, the plurality of first working parts 121 are arranged on the surfaces of the plurality of shape-changing parts 112 and the plurality of annular extending protrusions, and the plurality of second working parts 122 are arranged on the surfaces of the plurality of annular extending recesses. Two first working parts 121 connected and merged in adjacent basic units 10 form a merged first working part 121'. The shape and width of the merged first working part 121' correspond to the shape and width of a recess formed by grooving the curved side surface of a semiconductor crystal ingot, and the shape and width of each second working part 122 correspond to the shape and width of a protrusion formed by grooving the curved side surface of the semiconductor crystal ingot. The width of each second working part 122 is 2.5 times the width of each merged first working part 121'. In addition, the polishing layer 12 is formed on the surface of the extension portion 111 by chemical vapor deposition, that is, the first working portion 121 is formed on the surface of the shape changing portion 112 and the annular extending convex portion by chemical vapor deposition, and the second working portion 122 is formed on the surface of the annular extending concave portion by chemical vapor deposition.

[0053] See also Figure 8 , which is a schematic diagram illustrating and explaining some embodiments of the ingot polishing wheel 1 of the present invention polishing the grooved, arcuate side surface of a semiconductor ingot 9. Specifically, the ingot polishing wheel 1 of the present invention is composed of a plurality of basic units 10 arranged axially. Each basic unit 10 is defined by adjacent auxiliary dashed lines and includes a wheel-shaped body 11 and a polishing layer 12. The wheel-shaped body 11 has an axial hole defined at its axis, and the polishing layer 12 is disposed on a rim of the wheel-shaped body 11. The polishing layers 12 of the multiple basic units 10 are connected to form a continuous layer, which is the polishing layer 12 of the ingot polishing wheel 1. The wheel-shaped bodies 11 of the multiple basic units 10 are connected to form a continuous layer, which is the wheel-shaped body 11 of the ingot polishing wheel 1. The wheel-shaped body 11 has an extension portion 111 extending radially outward, and the extension portion 111 has a plurality of annular extension protrusions and a plurality of annular extension recesses, and each annular extension recess is arranged between two adjacent annular extension protrusions, and the surface of each annular extension recess is concave inwardly toward the direction of the axial hole relative to the surface of each annular extension protrusion. The polishing layer 12 has a plurality of first working parts 121 and a plurality of second working parts 122, and the polishing layer 12 is formed on the surface of the extension portion 111 by chemical vapor deposition. Specifically, the plurality of first working portions 121 are formed on the surfaces of the plurality of annular extending protrusions by chemical vapor deposition, and the plurality of second working portions 122 are formed on the surfaces of the plurality of annular extending recesses by chemical vapor deposition. When the ingot polishing wheel 1 is used to polish the grooved arcuate side surface of the semiconductor ingot 9, the shape and width of the combined first working portion 121' formed by the plurality of first working portions 121 being connected and combined corresponds to the shape and width of the plurality of ingot indentations 92 on the arcuate side surface of the semiconductor ingot 9, and the shape and width of the plurality of second working portions 122 correspond to the shape and width of the plurality of ingot protrusions 91 on the arcuate side surface of the semiconductor ingot 9. Therefore, the ingot polishing wheel 1 can polish the grooved arcuate side surface of the semiconductor ingot 9 in a simple and convenient manner.

[0054] Example 1: Ingot polishing wheel

[0055] The ingot polishing wheel 1 of Example 1 is basically as follows Figure 4 and Figure 5The embodiment shown is manufactured as a multi-blade grinding wheel, wherein the wheel-shaped body 11 and the polishing layer 12 of the ingot polishing grinding wheel 1 of Example 1 are each integrally formed (ie, the combination of multiple basic units 10 is integrally formed). Specifically, a wheel-shaped body 11 is provided with an axial hole opened at the axis center, and the wheel-shaped body 11 has an extension portion 111 extending radially outward, and the extension portion 111 has a plurality of annular extension protrusions and a plurality of annular extension recesses, and each annular extension recess is arranged between two adjacent annular extension protrusions, and the surface of each annular extension recess is concavely formed inwardly toward the axial hole relative to the surface of each annular extension protrusion; then a polishing material is formed on the surface of the extension portion 111 by chemical vapor deposition to obtain a polishing layer 12, that is, the crystal ingot polishing wheel 1 of Example 1 is prepared; wherein, the polishing layer 12 has a plurality of first working parts 121 and a plurality of second working parts 122, the plurality of first working parts 121 are arranged on the surface of the plurality of annular extension protrusions, and the plurality of second working parts 122 are arranged on the surface of the plurality of annular extension recesses. In the axial cross-section of the ingot polishing grinding wheel 1 of Example 1, the combined first working portion 121', formed by the connected and combined first working portions 121, is rectangular in shape and has a width of 165 μm. Each second working portion 122 is arc-shaped and has a width of 450 μm. The wheel-shaped body 11 is made of stainless steel, and the polishing material (i.e., the material of the polishing layer 12) is diamond-like carbon.

[0056] Example 2: Ingot polishing wheel

[0057] The preparation process of Example 2 is similar to that of Example 1, the main difference being that the polishing material used in Example 2 is titanium nitride. Other preparation processes are in accordance with Example 1 to obtain the ingot polishing grinding wheel 1 of Example 2.

[0058] Test Example 1: Polishing Effect Evaluation

[0059] (1) Determine the average surface roughness Ra of the wafer edge

[0060] like Figure 9A As shown, according to the semiconductor wafer production process commonly used in the prior art, after the wafer W is cut from the semiconductor crystal ingot 9 with a wire saw L, the edge of the cut wafer W is ground using a conventional grinding wheel 2, and then the edge of the ground wafer W is polished using a polishing pad 3 and a polishing liquid.

[0061] In addition, if Figure 9B As shown, the present invention first uses a grooving grinding wheel 4 to groove the side surface of the semiconductor crystal ingot 9 to form grooves and protrusions, and then uses the crystal ingot polishing grinding wheel 1 of Example 1 to polish the grooves and protrusions on the side surface of the semiconductor crystal ingot 9.

[0062] Subsequently, the edge morphology of the four groups of wafers, namely, the convex portion of the side surface of the semiconductor ingot polished in Example 1 (equivalent to the edge of the wafer cut later), the wafer cut but not processed, the wafer ground with a conventional grinding wheel, and the wafer polished with a polishing pad and polishing liquid, was observed using a wafer edge measurement machine (manufacturer: Kobe Steel, Ltd. (KOBELCO), Japan; model: LEP-2200), and the surface average roughness Ra of the wafer edge of each group was measured using an atomic force microscope (AFM). Among them, the measurement results of the semiconductor ingot material selected as silicon carbide are listed in Figure 10A The results of the determination of silicon as the semiconductor ingot material are listed in Figure 10B The group polished in Example 1 is referred to as "Example 1", the group of wafers cut but not processed is referred to as "unprocessed", the group of wafers after grinding is referred to as "grinding wheel", and the group of wafers polished using a polishing pad and a polishing slurry is referred to as "polishing pad and polishing slurry".

[0063] Depend on Figure 10A The results show that if silicon carbide is selected as the material for semiconductor wafers, the edge of the untreated wafer group has a maximum surface average roughness Ra of 84.38nm. After grinding with a grinding wheel, the surface average roughness Ra of the wafer edge of the grinding wheel group can be reduced to 12.15nm. After further polishing with a polishing pad and polishing slurry, the surface average roughness Ra of the wafer edge of the polishing pad and polishing slurry group is further reduced to 0.48nm. Looking at the results of polishing using the ingot polishing wheel of Example 1, the surface average roughness Ra of the wafer edge of the Example 1 group is only 0.55nm, which is very close to the result of the polishing pad and polishing slurry group, and both sets of data are less than 1.5nm. Therefore, for silicon carbide semiconductor ingots or wafers, polishing with the ingot polishing wheel of Example 1 can indeed achieve almost the same results as polishing with a polishing pad and polishing slurry in the prior art, but without the high cost, low efficiency and wastewater treatment difficulties associated with polishing pad operation.

[0064] Depend on Figure 10BThe results show that if silicon is used as the material for semiconductor wafers, the edge of the untreated wafer group has a maximum average surface roughness Ra of 126.67nm. After grinding with a grinding wheel, the average surface roughness Ra of the wafer edge of the grinding wheel group can be reduced to 11.56nm. After further polishing with a polishing pad and polishing slurry, the average surface roughness Ra of the wafer edge of the polishing pad and polishing slurry group is further reduced to 0.5nm. Looking at the results of polishing using the ingot polishing wheel of Example 1, the average surface roughness Ra of the wafer edge of the Example 1 group is only 0.56nm, which is very close to the result of the polishing pad and polishing slurry group, and both sets of data are less than 3nm. Therefore, for silicon semiconductor ingots or wafers, polishing with the ingot polishing wheel of Example 1 can indeed achieve almost the same results as polishing using a polishing pad and polishing slurry in the prior art, but without the high cost, low efficiency and wastewater treatment difficulties associated with polishing pad operation.

[0065] (2) Surface morphology of the wafer edge

[0066] Carbon is selected as the material of the semiconductor ingot, and then Figure 9A As shown, according to the semiconductor wafer production process commonly used in the prior art, after the wafer W is cut from the semiconductor crystal ingot 9 with a wire saw L, the edge of the cut wafer W is ground using a conventional grinding wheel 2, and then the edge of the ground wafer W is polished using a polishing pad 3 and a polishing liquid.

[0067] In addition, if Figure 9B As shown, the present invention first selects a grooving grinding wheel 4 to groove the side surface of the semiconductor crystal ingot 9 to form grooves and protrusions, and then selects the crystal ingot polishing grinding wheel 1 of Example 1 and Example 2 to polish the grooves and protrusions on the side surfaces of different semiconductor crystal ingots 9 respectively.

[0068] Subsequently, for the five groups of the convex portion of the side surface of the semiconductor crystal ingot polished by Example 1 and Example 2 (i.e., equivalent to the edge of the wafer that is subsequently cut off), the wafer that has been cut but not processed, the wafer that has been ground by a conventional grinding wheel, and the wafer that has been polished using a polishing pad and a polishing liquid, optical images of the wafer edges of the groups are obtained by a wafer edge measurement machine, and their morphologies can be observed; wherein, the groups polished by Example 1 and Example 2 are referred to as "Example 1" and "Example 2" respectively, the group of the wafer that has been cut but not processed is referred to as "unprocessed", the group of the wafer that has been ground is referred to as "grinding wheel", and the group of the wafer that has been polished using a polishing pad and a polishing liquid is referred to as "polishing pad and polishing liquid". The optical images of the five groups of Example 1, Example 2, unprocessed, grinding wheel, and polishing pad and polishing liquid are shown in order. Figures 11A to 11Eshown.

[0069] Depend on Figure 11C It can be seen that the untreated group was cut directly with a wire saw, with its edge perpendicular to the wafer surface and without any external shaping, so the surface roughness of the wafer edge is high. Therefore, in the optical image, the wafer edge (as indicated by the arrow) does not show a white reflective area. Figure 11D The grinding wheel group has reduced the surface roughness of the wafer by grinding it, so in the optical image, a white reflective area can be observed in part of the wafer edge (as indicated by the arrow). Figure 11E The polishing pad and polishing liquid combination can further polish the wafer to reduce the surface roughness to a mirror-like effect. Therefore, in the optical image, the edge of the wafer (as indicated by the arrow) can be clearly observed as a white reflective area. Figure 11A and Figure 11B , Example 1 and Example 2 groups both used the ingot polishing wheel of the present invention to polish the semiconductor ingot, so in the optical image of the group, the edge of the wafer (as indicated by the arrow) can be clearly observed to have a white reflective area, and Figure 11A and Figure 11B The obvious reflective areas in the Figure 11E It can be seen that the ingot polishing wheel of Example 1 or Example 2 can achieve almost the same effect as the polishing using the polishing pad combined with the polishing liquid in the prior art.

[0070] Based on this, it can be seen from the results of the above-mentioned Test Example 1 that the ingot polishing wheel of the present invention can indeed have a polishing effect almost the same as the technical means of polishing using soft materials in the prior art, but the ingot polishing wheel of the present invention can avoid the problems of difficult control, complexity and difficulty of operation caused by the use of soft materials for polishing.

[0071] In summary, the ingot polishing wheel of the present invention has a structural design that corresponds to the shape of the side surface of the grooved semiconductor ingot, thereby avoiding the shortcomings of the existing technology of using soft materials for polishing, such as difficulty in control, complexity and difficulty in operation. It can also solve the problems of sub-surface damage and high surface roughness on the edge of the semiconductor ingot or wafer, and therefore has a very high commercial value.

Claims

1. A crystal ingot polishing grinding wheel, characterized in that: Include: A basic unit, comprising: A wheel-shaped body having an axial hole defined at its axis; the wheel-shaped body having an extension portion extending radially outward, the extension portion having two annular extension protrusions and an annular extension recess, the annular extension recess being disposed between the two annular extension protrusions and being concave inwardly toward the axial hole relative to the two annular extension protrusions; as well as a polishing layer having two first working portions and a second working portion, and formed on the surface of the extension portion; In which, the two first working parts are arranged on the surface of the two annular extended protrusions, and the second working part is arranged on the surface of the annular extended concave part; the shape and width of the two first working parts correspond to the shape and width of the indentation formed by grooving on the arcuate side surface of a semiconductor crystal ingot, and the shape and width of the second working part correspond to the shape and width of the protrusion formed by grooving on the arcuate side surface of the semiconductor crystal ingot.

2. The ingot polishing grinding wheel according to claim 1, wherein: The polishing layer is formed on the surface of the extension portion by vapor deposition or electrochemical deposition.

3. The ingot polishing grinding wheel according to claim 1, wherein: The polishing layer is made of a rigid material, which includes diamond, diamond-like carbon, silicon carbide, metal nitride, metal carbide, metal oxide, rigid resin or a combination thereof.

4. The ingot polishing grinding wheel according to claim 1, wherein: The polishing layer is made of a soft material, which includes soft resin, rubber or a combination thereof.

5. The ingot polishing grinding wheel according to claim 1, wherein: The thickness of the polishing layer is greater than 1 micron and less than 1 centimeter.

6. The ingot polishing grinding wheel according to claim 5, wherein: The polishing layer has a thickness greater than or equal to 20 micrometers and less than or equal to 500 micrometers.

7. The ingot polishing grinding wheel according to claim 1, wherein: The extension portion also includes two shape-changing portions, which are formed by the two annular extension protrusions extending radially outward; in the axial cross-section of the wheel-shaped body, the shapes of the top ends of the two shape-changing portions independently include acute angles, arcs, obtuse angles or polygons.

8. The ingot polishing grinding wheel according to claim 1, wherein: The ingot polishing grinding wheel further includes a functional layer, which is arranged between the surface of the extension portion and the polishing layer.

9. The ingot polishing grinding wheel according to claim 1, wherein: The material of the wheel-shaped body includes a metal material, a resin, a fiber material, a carbide or a ceramic material.

10. A crystal ingot polishing grinding wheel, characterized in that: It contains multiple basic units, and each basic unit is arranged axially and close to each other; Each basic unit contains: A wheel-shaped body having an axial hole defined at its axis; the wheel-shaped body having an extension portion extending radially outward, the extension portion having two annular extension protrusions and an annular extension recess, the annular extension recess being disposed between the two annular extension protrusions and being concave inwardly toward the axial hole relative to the two annular extension protrusions; as well as a polishing layer having two first working portions and a second working portion, and formed on the surface of the extension portion; In which, the two first working parts are arranged on the surface of the two annular extended protrusions, and the second working part is arranged on the surface of the annular extended concave part; the two first working parts connected and merged in adjacent basic units constitute a merged first working part, and the shape and width of the merged first working part correspond to the shape and width of the indentation formed by grooving on the arcuate side surface of a semiconductor crystal ingot, and the shape and width of the second working part correspond to the shape and width of the convex part formed by grooving on the arcuate side surface of the semiconductor crystal ingot.

11. The ingot polishing grinding wheel according to claim 10, wherein: The combination of the plurality of basic units is assembled into one piece through the shaft hole; or the combination of the plurality of basic units is formed into one piece.

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