A grinding wheel assembly and a wafer manufacturing method

Abstract

This invention provides a grinding wheel assembly and a wafer manufacturing method. The grinding wheel assembly includes a first grinding wheel, which comprises a cylindrical first main body and a first grinding portion formed on the outer peripheral surface of the first main body. The top surface of the first grinding portion is flat, and the bottom surface of the first grinding portion is partially inclined away from the top surface of the first grinding portion and forms a first grinding surface and a second grinding surface connected at one end to the first grinding surface. The other end of the second grinding surface is connected to the first main body. The distance from the end of the first grinding surface near the first main body to the top surface of the first grinding portion is less than the distance from the end of the second grinding surface near the first main body to the top surface of the first grinding portion. The first grinding surface has a first acute angle with the axial direction of the first main body, and the second grinding surface has a second acute angle with the axial direction of the first main body. The first acute angle is smaller than the second acute angle. When using the grinding wheel assembly to grind wafers to achieve edge removal, edge chipping can be reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor, and particularly relates to a grinding wheel assembly and a wafer manufacturing method. BACKGROUND

[0002] SOI (Silicon on Insulator) technology realizes the medium isolation of the components in integrated circuits by introducing a buried layer of silicon dioxide between the silicon substrate and the top layer of silicon thin film, completely eliminates the parasitic latch effect of bulk silicon SMOS circuits, and also significantly reduces the parasitic capacitance, improves the integration density and running speed. It has the core advantages of small short channel effect and simple process, and is particularly suitable for low-voltage and low-power circuits, and is one of the mainstream technologies of deep submicron integrated circuits.

[0003] BESOI (Backside Etching) is a technology for preparing SOI material by low-temperature bonding a device layer with a silicon dioxide layer and a support layer, and then etching or grinding the device layer from the back. Its core feature is that it can obtain a top layer of silicon thin film with good quality. Grinding the device layer to achieve edge removal is one of the important steps of BESOI technology, but in the prior art, when the device layer is ground, edge collapse abnormalities often occur within 1.5 mm of the edge of the device layer, causing defects such as holes and pits in the edge of the device layer. SUMMARY

[0004] The present application aims to provide a grinding wheel assembly and a manufacturing method to solve the above technical problems.

[0005] To achieve the above-mentioned purpose, the present application provides a grinding wheel assembly, comprising: a first grinding wheel for installation on a chamfering machine, the first grinding wheel comprising a cylindrical first body portion and a first grinding portion formed on the outer peripheral surface of the first body portion, the top surface of the first grinding portion being a plane perpendicular to the axis of the first body portion, the bottom surface of the first grinding portion being partially inclined away from the top surface of the first grinding portion and forming a first grinding surface and a second grinding surface connected to the first grinding surface at one end, the other end of the second grinding surface being connected to the first body portion; the distance from the first grinding surface near the end of the first body portion to the top surface of the first grinding portion is less than the distance from the second grinding surface near the end of the first body portion to the top surface of the first grinding portion, the first grinding surface has a first acute angle with the axis direction of the first body portion, the second grinding surface has a second acute angle with the axis direction of the first body portion, and the first acute angle is smaller than the second acute angle.

[0006] Optionally, the first grinding portion further comprises a third grinding surface formed on the bottom surface of the first grinding portion and perpendicular to the axis of the first body portion, one end of the third grinding surface being connected to the second grinding surface and the other end being connected to the first body portion.

[0007] Optionally, the first grinding surface has a width x1 on the top surface of the first grinding portion, the second grinding surface has a width x2 on the top surface of the first grinding portion, and the third grinding surface has a width x3 on the top surface of the first grinding portion, wherein x1 is 1mm-1.75mm, x2 is 1mm-1.75mm, and the sum of x1, x2 and x3 is 2.5mm-3.5mm.

[0008] Optionally, the first acute angle is 45°-60°, and the second acute angle is 60°-85°.

[0009] Optionally, the chamfering machine further comprises a second grinding wheel mounted on the chamfering machine, the second grinding wheel comprising a cylindrical second main portion and a second grinding portion formed on the outer circumferential surface of the second main portion, the top surface of the second grinding portion being a plane perpendicular to the axis of the second main portion, the bottom surface of the second grinding portion being partially inclined away from the top surface of the second grinding portion and formed into a fourth grinding surface, the fourth grinding surface and the axis of the second main portion defining a third acute angle; the second grinding portion further comprises a fifth grinding surface formed on the bottom surface of the second grinding portion and perpendicular to the axis of the second main portion, one end of the fifth grinding surface being connected to the fourth grinding surface, and the other end being connected to the second main portion.

[0010] Optionally, the fourth grinding surface has a width x4 on the top surface of the second grinding portion, and the fifth grinding surface has a width x5 on the top surface of the second grinding portion, x4 being equal to the sum of the width of the first grinding surface on the top surface of the first grinding portion and the width of the second grinding surface on the top surface of the first grinding portion, and the sum of x4 and x5 being 2.5mm-3.5mm.

[0011] Optionally, the third acute angle is 45°-60°.

[0012] Optionally, the roughness of the first grinding surface and the second grinding surface is greater than the roughness of the fourth grinding surface and the fifth grinding surface.

[0013] To achieve the above object, the application further provides a wafer manufacturing method, which is performed based on the grinding wheel assembly as described above, and comprises the following steps: providing a wafer blank, wherein the wafer blank comprises a support wafer and a device wafer blank which are bonded to each other; placing the wafer blank at the first grinding wheel, arranging the device wafer blank towards the bottom surface of the first grinding part, and grinding the device wafer blank by at least the first grinding surface and the second grinding surface, so that the device wafer blank is partially ground and a first notch is formed which matches the first grinding surface and the second grinding surface; and performing edge single-side etching on the wafer blank after grinding.

[0014] Optionally, when the grinding operation is performed by using the first grinding wheel, the first grinding wheel rotates at a speed of 8000 rpm to 9000 rpm, and the wafer blank rotates at a linear speed of 10 mm / s to 25 mm / s.

[0015] Optionally, the grinding wheel assembly further comprises a second grinding wheel which is installed on the chamfering machine, wherein the second grinding wheel comprises a cylindrical second main part and a second grinding part which is formed on the outer circumferential surface of the second main part, the top surface of the second grinding part is a plane which is perpendicular to the axis of the second main part, the bottom surface of the second grinding part is partially inclined away from the top surface of the second grinding part and is formed into a fourth grinding surface, and the fourth grinding surface and the axis direction of the second main part define a third acute angle; the second grinding part further comprises a fifth grinding surface which is formed on the bottom surface of the second grinding part and is perpendicular to the axis of the second main part, one end of the fifth grinding surface is connected with the fourth grinding surface, and the other end of the fifth grinding surface is connected with the second main part; before the edge single-side etching is performed, the wafer manufacturing method further comprises the following steps: placing the wafer blank after grinding by the first grinding wheel at the second grinding wheel, arranging the first notch towards the bottom surface of the second grinding part, and grinding the position of the device wafer blank which is close to the first notch by the fourth grinding surface and the fifth grinding surface, and forming a second notch which matches the fourth grinding surface and the fifth grinding surface.

[0016] Optionally, when the grinding operation is performed by using the second grinding wheel, the second grinding wheel rotates at a speed of 8000 rpm to 9000 rpm, and the wafer blank rotates at a linear speed of 10 mm / s to 15 mm / s.

[0017] Compared with the prior art, the grinding wheel assembly and the wafer manufacturing method have the following advantages: the grinding wheel assembly comprises a first grinding wheel, the first grinding wheel comprises a first main body part and a first grinding part arranged on the outer circumferential surface of the first main body part, the top surface of the first grinding part is a plane perpendicular to the axis of the first main body part, the bottom surface of the first grinding part comprises a first grinding surface and a second grinding surface, the first grinding surface and the second grinding surface are inclined relative to the axis of the first main body part in the same direction, the first grinding surface has a first acute angle with the direction of the axis of the first main body part, the second grinding surface has a second acute angle with the direction of the axis of the first main body part, and the first acute angle is smaller than the second acute angle. The grinding wheel assembly is used for grinding a wafer wafer by at least the first grinding surface and the second grinding surface of the first grinding wheel during the wafer manufacturing process, so as to realize edge removal, form a first notch, and make the angle of the edge at the formed first notch gentle and the residual silicon layer thick, thereby avoiding the occurrence of the problem of edge collapse caused by tearing of the silicon layer due to the silicon layer being too thin during subsequent processing, and improving the quality of the edge of the manufactured wafer. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are used to better understand the present application and do not constitute undue limitations on the present application.

[0019] Figure 1 FIG. 1 is a structural schematic view of a first grinding wheel of a grinding wheel assembly according to an embodiment of the present application.

[0020] Figure 2 FIG. 2 is an enlarged schematic view of A in FIG. 1. Figure 1

[0021] Figure 3 FIG. 3 is a structural schematic view of a second grinding wheel of a grinding wheel assembly according to an embodiment of the present application.

[0022] Figure 4 FIG. 4 is an enlarged schematic view of B in FIG. 3. Figure 3

[0023] Figure 5 FIG. 5 is a flow chart of a wafer manufacturing method according to an embodiment of the present application.

[0024] Figure 6 FIG. 6 is a flow chart of a wafer manufacturing method according to another embodiment of the present application.

[0025] Figure 7 FIG. 7 is a structural schematic view of a wafer wafer used in a wafer manufacturing method according to an embodiment of the present application.

[0026] Figure 8 ​​Fig. 1 is a schematic view of a wafer manufacturing method according to an embodiment of the present application, in which a device wafer of a wafer original is oriented toward a first grinding portion.

[0027] Figure 9 Fig. 2 is a schematic view of a wafer manufacturing method according to an embodiment of the present application, in which the first grinding portion grinds the device wafer.

[0028] Figure 10 Fig. 3 is a schematic view of a wafer manufacturing method according to an embodiment of the present application, in which a first transition wafer is formed.

[0029] Figure 11 Fig. 4 is a schematic view of a wafer manufacturing method according to an embodiment of the present application, in which a first transition device wafer of the first transition wafer is oriented toward a second grinding portion.

[0030] Figure 12 Fig. 5 is a schematic view of a wafer manufacturing method according to an embodiment of the present application, in which the second grinding portion grinds the first transition wafer.

[0031] Figure 13 Fig. 6 is a schematic view of a wafer manufacturing method according to an embodiment of the present application, in which a second transition wafer is formed.

[0032] Figure 14 Fig. 7 is a schematic view of a wafer manufactured by a wafer manufacturing method according to an embodiment of the present application.

[0033] Figure 15 Fig. 8 is a topographic view of an edge of a wafer manufactured by a wafer manufacturing method according to an embodiment of the present application.

[0034] Figure 16 Fig. 9 is a topographic view of an edge of a wafer manufactured by a wafer manufacturing method according to a comparative example of the present application.

[0035] [Explanation of Reference Numerals] 100 - first grinding wheel, 110 - first main portion, 120 - first grinding portion, 1201 - first grinding surface, 1202 - second grinding surface, 1203 - third grinding surface, 200 - second grinding wheel, 210 - second main portion, 220 - second grinding portion, 2201 - fourth grinding surface, 2202 - fifth grinding surface, 1 - wafer, 01 - wafer original, 001 - first transition wafer, 0001 - second transition wafer, 011 - support wafer, 012 - device wafer, 0012 - first transition device wafer, 0121 - first notch, 0122 - second notch. DETAILED DESCRIPTION

[0036] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show components related to the present invention and are not drawn according to the actual number, shape, and size of components in the actual implementation. In the actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0037] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of the present invention must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, provided it is feasible, those skilled in the art can, based on the disclosure of the present invention and depending on design specifications or implementation requirements, selectively implement some or all technical features in any embodiment, or selectively implement a combination of some or all technical features in multiple embodiments, thereby increasing the flexibility in implementing the present invention.

[0038] As used in this specification, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. As used in this specification, the term "or" is generally employed in its sense of "and / or" unless the content clearly dictates otherwise, and the term "have" or "has" is used interchangeably with "comprise" or "comprises". The term "mount", "connected", "connection" should be understood broadly, for example, can be fixed connection, can also be detachable connection, or integral connection. It can be mechanical connection, or electrical connection. It can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. The relationship terms such as "first", "second" and the like are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations, nor indicate or imply relative importance or implicitly indicate the number of technical features indicated. It should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the present application. The specific meanings of the above terms in the present application can be understood by those skilled in the art according to the specific circumstances.

[0039] One of the purposes of the embodiments of the present application is to provide a grinding wheel assembly for grinding a wafer raw sheet to achieve edge removal when manufacturing a wafer, and to improve the quality of the manufactured wafer.

[0040] In order to make the purposes, advantages and characteristics of the present application clearer, the present application will be further described in detail below in combination with the drawings. It should be noted that the drawings are all very simplified and use non-precise proportions, and are only used to facilitate and clearly assist in describing the purposes of the embodiments of the present application. The same or similar reference numerals in the drawings represent the same or similar parts.

[0041] As Figures 1 to 2As shown, the grinding wheel assembly provided in this embodiment of the invention includes a first grinding wheel 100 for mounting on a chamfering machine. The first grinding wheel 100 includes a cylindrical first main body 110 and a first grinding portion 120 formed on the outer peripheral surface of the first main body 110. The top surface of the first grinding portion 120 is a plane perpendicular to the axis of the first main body 110. The bottom surface of the first grinding portion 120 is partially inclined away from the top surface of the first grinding portion 120 and forms a first grinding surface 1201 and a second grinding surface 1202, one end of which is connected to the first grinding surface 1201. The other end of the second grinding surface 1202 is connected to the first main body 110. The distance from the end of the first grinding surface 1201 near the first main body 110 to the top surface of the first grinding portion 120 is less than the distance from the end of the second grinding surface 1202 near the first main body 110 to the top surface of the first grinding portion 120. The first grinding surface 1201 has a first acute angle α with the axial direction of the first main body 110. The second grinding surface 1202 has a second acute angle β with the axial direction of the first main body 110. The first acute angle α is smaller than the second acute angle β.

[0042] It should be noted that the top and bottom surfaces of the first grinding portion 120 are axially opposite to those of the first main body portion 110. Figure 1 and Figure 2 In the orientation shown, the top surface of the first grinding part 120 is the upper surface of the first grinding part 120, and the bottom surface of the first grinding part 120 is the lower surface of the first grinding part 120.

[0043] The grinding wheel assembly is used in the fabrication of wafer 1 (e.g., Figure 14 As shown) during the process of processing wafer 01 (as shown) Figure 7 The wafer 1 is ground to remove edges. When the wafer 1 is edge-removed using the grinding wheel assembly, edge chipping can be reduced, thus improving the quality of the wafer 1.

[0044] The wafer 1 includes, but is not limited to, an SOI wafer. When the wafer 1 is an SOI wafer, as... Figure 7 As shown, the wafer 01 includes a support sheet 011 and a device wafer 012 bonded together.

[0045] Taking wafer 1 as an example of an SOI wafer, the process of manufacturing wafer 1 using the grinding wheel assembly can be as follows: Figure 5 As shown, it includes steps S1, S2 and S3.

[0046] Step S1 includes: providing, for example Figure 7 The wafer 01 shown is shown.

[0047] Step S2 includes: placing the wafer 01 on the first grinding wheel 100, and arranging the device wafer 012 facing the bottom surface of the first grinding section 120 (e.g., Figure 8 As shown), and at least the first grinding surface 1201 and the second grinding surface 1202 grind the original device wafer 012 (as shown). Figure 9 As shown), so that a portion of the original device wafer 012 is ground away to form a first notch 0121 that matches the first grinding surface 1201 and the second grinding surface 1202 (as shown). Figure 10 (As shown).

[0048] Step S3 includes: performing edge single-sided etching on the ground wafer 01 to obtain wafer 1.

[0049] Depend on Figure 10 As can be seen, a first obtuse angle θ is formed at the first notch 0121. The angle of the first obtuse angle θ is the sum of the angle of the first acute angle α and the angle of the supplementary angle of the second acute angle β. That is, through the grinding of the first grinding wheel 100, the angle at the first notch 0121 is made gentler, thereby making the residual silicon layer at the edge of the first notch 0121 thicker. Thus, in subsequent processing, tearing due to the excessively thin edge silicon layer can be avoided, thus preventing edge chipping and improving the edge quality of the obtained wafer 1. Here, the "subsequent processing" includes at least step S3, and may also include step S4 as described later.

[0050] In this paper, after the processing in step S2, the wafer 01 is formed into a first transition wafer 001 (e.g., Figure 10 (As indicated in the text). It is easy to understand that when step S3 is executed directly after step S2 (i.e., as shown in the text). Figure 5 As shown in the figure, the "polished wafer 01" refers to the first transition wafer 001.

[0051] In practice, the angles of the first acute angle α and the second acute angle β are determined as needed. For example, the angle of the first acute angle α can be selected within the range of 45° to 60°, and the angle of the second acute angle β can be selected within the range of 60° to 85°. Furthermore, it can be understood that in this embodiment of the invention, the distance from the first grinding surface 1201 to the axis of the first main body 110 and the distance from the second grinding surface 1202 to the axis of the first main body 110 both decrease along the direction from the top surface to the bottom surface of the first grinding part 120.

[0052] In some embodiments, the second grinding surface 1202 is directly connected to the first body portion 110. In other embodiments, reference continues to this section.Figure 1 and Figure 2 The first grinding portion 120 further includes a third grinding surface 1203 formed on the bottom surface of the first grinding portion 120 and perpendicular to the axis of the first main body portion 110. One end of the third grinding surface 1203 is connected to the second grinding surface 1202, and the other end is connected to the first main body portion 110. In other words, the second grinding surface 1202 is connected to the first main body portion 110 through the third grinding surface 1203. Thus, in step S2, the edge of the device wafer 012 can be partially located on the side of the second grinding surface 1202 closer to the first main body portion 110, and the device wafer 012 is also ground using the third grinding surface 1203.

[0053] In this embodiment of the invention, when the first grinding surface 1201, the second grinding surface 1202, and the third grinding surface 1203 are projected onto the top surface of the first grinding part 120 along the axis of the first main body 110, the width of the projection of the first grinding surface 1201 onto the top surface of the first grinding part 120 is x1, the width of the projection of the second grinding surface 1202 onto the top surface of the first grinding part 120 is x2, and the width of the projection of the third grinding surface 1203 onto the top surface of the first grinding part 120 is x3. The specific values ​​of x1, x2, and x3 are determined as needed. In a non-limiting embodiment, the value of x1 ranges from 1 mm to 1.75 mm, the value of x2 ranges from 1 mm to 1.75 mm, and the sum of x1, x2, and x3 is 2.5 mm to 3.5 mm. Here, "width" refers to the dimension in the radial direction of the first grinding part 120.

[0054] In addition, the mesh size of the first grinding surface 1201, the second grinding surface 1202 and the third grinding surface 1203 can be selected in the range of 800 mesh to 1000 mesh.

[0055] Preferably, please return to the reference. Figure 1 The first grinding wheel 100 includes a plurality of first grinding sections 120, which are spaced apart along the axial direction of the first main body 110. Each first grinding section 120 can grind one of the device wafers 012 of the wafer 01. In this way, the first grinding wheel 100 can grind multiple wafers 01 simultaneously, thereby improving production efficiency.

[0056] It is understood that when the first grinding wheel 100 includes a plurality of first grinding portions 120 arranged at axial intervals along the first main body 110, the top surface of one of the two adjacent first grinding portions 120 is arranged face-to-face with the bottom surface of the other first grinding portion 120 to isolate the two adjacent wafers 01 when the first grinding wheel 100 grinds the plurality of wafers 01 simultaneously. Furthermore, the minimum distance h1 between two adjacent first grinding portions 120 should be greater than the axial dimension of the wafer 01. This prevents the support piece 011 of the wafer 01 from contacting the other of the two adjacent first grinding portions 120 when the wafer 01 is placed between two adjacent first grinding portions 120 for grinding by one of the two adjacent first grinding portions 120.

[0057] In an optional example, when the axial dimension of the support sheet 011 is in the range of 773um to 777um, and the dimension of the device wafer 012 is in the range of 773um to 777um, the minimum distance h1 between two adjacent first grinding portions 120 can be selected in the range of 1.8mm to 3mm. Additionally, the minimum axial dimension h2 of each first grinding portion 120 in the first body portion 110 can be selected in the range of 2 to 7mm. Here, the minimum axial dimension h2 of the first grinding portion 120 in the first body portion 110 refers to the distance from the end of the first grinding surface 1201 away from the first body portion 110 to the top surface of the first grinding portion 120.

[0058] In a further preferred embodiment, the grinding wheel assembly further includes a second grinding wheel 200 for mounting on the chamfering machine (e.g., ...). Figure 3 and Figure 4 (As shown). Please refer to this carefully. Figure 3 and Figure 4 The second grinding wheel 200 includes a cylindrical second main body 210 and a second grinding portion 220 formed on the outer peripheral surface of the second main body 210. The top surface of the second grinding portion 220 is a plane perpendicular to the axis of the second main body 210. The bottom surface of the second grinding portion 220 is partially inclined away from the top surface of the second grinding portion 220 and formed as a fourth grinding surface 2201. The fourth grinding surface 2201 has a third acute angle γ with the axial direction of the second main body 210. The second grinding portion 220 also includes a fifth grinding surface 2202 formed on the bottom surface of the second grinding portion 220 and perpendicular to the axis of the second main body 210. One end of the fifth grinding surface 2202 is connected to the fourth grinding surface 2201, and the other end is connected to the second main body 210.

[0059] It is easy to understand that the distance from the fourth grinding surface 2201 to the axis of the second main body 210 decreases along the direction from the top surface to the bottom surface of the second grinding part 220. The top surface and the bottom surface of the second grinding part 220 are opposite each other in the axial direction of the second main body 210. Figure 3 and Figure 4 In the orientation shown, the top surface of the second grinding part 220 is the upper surface of the second grinding part 220, and the bottom surface of the second grinding part 220 is the lower surface of the second grinding part 220.

[0060] In the case where the grinding wheel assembly includes the second grinding wheel 200, such as Figure 6 As shown, the process of manufacturing the wafer 1 using the grinding wheel assembly may further include step S4, which is performed after step S2 and before step S3.

[0061] In this document, the original device chip 012 after the processing in step S2 is referred to as the first transition device chip 0012.

[0062] like Figure 6 As shown, step S4 includes: placing the first transition wafer 001 on the second grinding wheel 200, and arranging the first notch 0121 of the first transition device wafer 0012 towards the bottom surface of the second grinding section 220 (e.g., Figure 11 As shown), and the fourth grinding surface 2201 and the fifth grinding surface 2202 grind the position of the first transition device piece 0012 near the first notch 0121 (as shown). Figure 12 As shown), so that a portion of the first transition device sheet 0012 is ground away to form a second notch 0122 that matches the fourth grinding surface 2201 and the fifth grinding surface 2202 (as shown). Figure 13 (As shown).

[0063] Depend on Figure 13 As can be seen, a second obtuse angle η is formed at the second notch 0122. The angle of the second obtuse angle η is equal to the angle of the third acute angle γ plus 90°. The angle of the third acute angle γ can be selected within the range of 45° to 60°. In some examples, the third acute angle γ is equal to the first acute angle, so the second obtuse angle η is less than the first obtuse angle θ.

[0064] After the processing in step S4, the first transition wafer 001 is formed as shown. Figure 13The second transition wafer 0001 is shown. When step S3 is executed after step S4 is completed, the "grinding wafer 01" refers to the second transition wafer 0001.

[0065] In this embodiment of the invention, preferably, the roughness of the fourth grinding surface 2201 and the fifth grinding surface 2202 is less than the roughness of the first grinding surface 1201, the second grinding surface 1202, and the third grinding surface 1203. Thus, step S2 is equivalent to a coarse grinding operation with a relatively fast grinding speed, and step S4 is equivalent to a fine grinding operation for more precise edge removal.

[0066] In an optional embodiment, the mesh size of both the fourth grinding surface 2201 and the fifth grinding surface 2202 can be selected within the range of 1200 mesh to 2000 mesh.

[0067] When the fourth grinding surface 2201 and the fifth grinding surface 2202 are projected onto the top surface of the second grinding part 220 along the axis of the second main body 210, the width of the projection of the fourth grinding surface 2201 onto the top surface of the second grinding part 220 is x4, and the width of the projection of the fifth grinding surface 2202 onto the top surface of the second grinding part 220 is x5. The specific values ​​of x4 and x5 are set as needed. In a non-limiting embodiment, x4 is equal to the sum of x1 and x2, and the sum of x4 and x5 can be selected in the range of 2.5mm to 3.5mm. In some examples, x5 can be equal to x3.

[0068] Preferably, please refer to Figure 3 The second grinding wheel 200 includes a plurality of second grinding sections 220, which are arranged at intervals along the axial direction of the second main body 210. Each second grinding section 220 can grind the first transition device wafer 0012 of one first transition wafer 001. In this way, the second grinding wheel 200 can grind multiple first transition wafers 001 simultaneously, improving production efficiency.

[0069] It is understood that when the second grinding wheel 200 includes a plurality of second grinding portions 220 spaced axially along the second main body 210, the bottom surface of one of the two adjacent second grinding portions 220 is arranged face-to-face with the top surface of the other second grinding portion 220 to isolate adjacent first transition wafers 001 when the second grinding wheel 200 simultaneously grinds a plurality of first transition wafers 001. Furthermore, the minimum distance h3 between adjacent second grinding portions 220 should be greater than the axial dimension of the first transition wafer 001. Thus, when the first transition wafer 001 is placed between adjacent second grinding portions 220 for grinding by one of the adjacent second grinding portions 220, contact between the support piece 011 of the first transition wafer 001 and the other of the adjacent second grinding portions 220 can be avoided.

[0070] In an optional example, the minimum distance h3 between two adjacent second grinding portions 220 may be equal to the minimum distance h1 between two adjacent first grinding portions 120. Furthermore, the minimum dimension h4 of each second grinding portion 220 in the axial direction of the second body portion 210 may be equal to the minimum dimension h2 of each first grinding portion 120 in the axial direction of the first body portion 110. Here, the minimum dimension h4 of the second grinding portion 220 in the axial direction of the second body portion 210 refers to the distance from the end of the fourth grinding surface 2201 away from the second body portion 210 to the top surface of the second grinding portion 220.

[0071] A second objective of this invention is to provide a wafer manufacturing method that can be used to manufacture SOI wafers. (Reference) Figure 5 The wafer manufacturing method includes at least steps S1, S2, and S3 as described above, and may further include step S4 (as described above). Figure 6 (As shown).

[0072] The wafer 01 is manufactured using existing technology. In an optional example, the support sheet 011 and the device wafer 012 are first thermally oxidized and then bonded, followed by a thermal hardening treatment to obtain the wafer 01. The thermal hardening treatment temperature is 900℃~1250℃, the time is 1h~3h, and the atmosphere during thermal hardening is a mixture of oxygen and an inert gas, or a mixture of hydrogen and an inert gas, wherein the inert gas includes, but is not limited to, at least one of argon and helium. Furthermore, the combined off-oriendation angle of the support sheet 011 and the device wafer 012 can be selected from 0.1°~0.6°, preferably from 0.2°~0.4°. The thickness of the support sheet 011 is selected from 773um~777um, and its total thickness deviation (TTV) is less than 0.4um. The thickness of the device wafer 012 is selected from 773um~777um, and its total thickness deviation is less than 0.4um.

[0073] In step S2, preferably, the wafer 01 is perpendicular to the axis of the first main body 110, and the edge of the device wafer 012 is partially aligned with the edge of the second polishing surface 1202 near the first main body 110. Alternatively, when the first polishing part 120 includes the third polishing surface 1203, the edge of the device wafer 012 is partially located on the side of the second polishing surface 1202 near the first main body 110. During polishing, the first grinding wheel 100 rotates at a speed of 8000 rpm to 9000 rpm and also moves in the direction from the device wafer 012 to the support sheet 011. The wafer 01 rotates at a linear velocity of 10 mm / s to 25 mm / s.

[0074] In step S4, preferably, the first transition wafer 001 is perpendicular to the axis of the second main body 210, and the fourth grinding surface 2201 is aligned with the first notch 0121. During grinding, the second grinding wheel 200 rotates at a speed of 8000 rpm to 9000 rpm and also moves in the direction from the first transition device wafer 0012 to the support wafer 011, while the first transition wafer 001 rotates at a linear velocity of 10 mm / s to 15 mm / s.

[0075] Step S3 can be performed with reference to existing technology, and will not be described in detail here.

[0076] The effects of the grinding wheel assembly and wafer manufacturing method provided by the present invention will be illustrated below through a specific embodiment and comparative examples.

[0077] The grinding wheel assembly used in Embodiment 1 includes a first grinding wheel 100 and a second grinding wheel 200, and the wafer manufacturing method includes steps S1, S2, S4 and S3.

[0078] Wherein, the angles of the first acute angle α and the third acute angle γ are both 45°, and the angle of the second acute angle β is 75°. The width x1 of the projection of the first grinding surface 1201 onto the top surface of the first grinding part 120 is 1 mm. The width x2 of the projection of the second grinding surface 1202 onto the top surface of the first grinding part 120 is 1 mm. The width x3 of the projection of the third grinding surface 1203 onto the top surface of the first grinding part 120 is 1 mm. The minimum distance h1 between two adjacent first grinding parts 120 is 1.8 mm. The minimum axial dimension h2 of the first grinding part 120 on the first main body 110 is 2 mm. The mesh size of the first grinding surface 1201, the second grinding surface 1202, and the third grinding surface 1203 is 800 mesh. The width of the projection of the fourth grinding surface 2201 onto the top surface of the second grinding part 220 is 2 mm. The width of the projection of the fifth grinding surface 2202 onto the top surface of the second grinding part 220 is 1 mm. The distance h3 between two adjacent second grinding parts 220 is 1.8 mm. The minimum axial dimension h4 of the second grinding part 220 in the second main body 210 is 2 mm. The mesh count of the fourth grinding surface 2201 and the fifth grinding surface 2202 is 1200 mesh.

[0079] In manufacturing wafer 1, in step S2, the rotational speed of the first grinding wheel 100 is 8000 rpm, and the linear velocity of the original wafer 01 during rotation is 25 mm / s. In step S4, the rotational speed of the second grinding wheel 200 is 8000 rpm, and the linear velocity of the first transition wafer 001 during rotation is 15 mm / s. In step S3, commercially available Spin-D solution is used to perform single-sided edge etching on the second transition wafer 0001 according to existing technology. The edge morphology of the wafer 1 obtained in this embodiment is as follows: Figure 15 As shown.

[0080] In Comparative Example 1, the second grinding wheel 200 was directly used to grind the wafer 01. The size of the second grinding wheel 200 used in this comparative example is the same as that in Example 1. The edge morphology of the wafer 1 obtained in this comparative example is as follows. Figure 16 As shown.

[0081] contrast Figure 15 and Figure 16As can be seen, the wafer 1 prepared in Example 1 has a smooth edge without holes or pits, while the wafer 1 prepared in Comparative Example 1 has more holes and pits on its edge, that is, the wafer 1 prepared in Comparative Example 1 has edge chipping problems.

[0082] While the present invention has been disclosed above, it is not limited thereto. Those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention also intends to include such modifications and variations.

Claims

1. A grinding wheel assembly, characterized by, The first grinding wheel for installation on a chamfering machine comprises a cylindrical first body portion and a first grinding portion formed on the outer peripheral surface of the first body portion, the top surface of the first grinding portion is a plane perpendicular to the axis of the first body portion, the bottom surface of the first grinding portion is partially inclined away from the top surface of the first grinding portion and forms a first grinding surface and a second grinding surface connected to the first grinding surface at one end, the other end of the second grinding surface is connected to the first body portion; the distance from the end of the first grinding surface close to the first body portion to the top surface of the first grinding portion is less than the distance from the end of the second grinding surface close to the first body portion to the top surface of the first grinding portion, the first grinding surface has a first acute angle with the axis direction of the first body portion, the second grinding surface has a second acute angle with the axis direction of the first body portion, and the first acute angle is smaller than the second acute angle. The second grinding wheel for installation on the chamfering machine comprises a cylindrical second body portion and a second grinding portion formed on the outer peripheral surface of the second body portion, the top surface of the second grinding portion is a plane perpendicular to the axis of the second body portion, the bottom surface of the second grinding portion is partially inclined away from the top surface of the second grinding portion and forms a fourth grinding surface, and the fourth grinding surface defines a third acute angle with the axis direction of the second body portion; the second grinding portion further comprises a fifth grinding surface formed on the bottom surface of the second grinding portion and perpendicular to the axis of the second body portion, one end of the fifth grinding surface is connected to the fourth grinding surface, and the other end is connected to the second body portion. The first grinding portion further comprises a third grinding surface formed on the bottom surface of the first grinding portion and perpendicular to the axis of the first body portion, one end of the third grinding surface is connected to the second grinding surface, and the other end is connected to the first body portion. The projection of the first grinding surface on the top surface of the first grinding portion has a width of x1, the projection of the second grinding surface on the top surface of the first grinding portion has a width of x2, and the projection of the third grinding surface on the top surface of the first grinding portion has a width of x3, wherein x1 is 1mm-1.75mm, x2 is 1mm-1.75mm, and the sum of x1, x2 and x3 is 2.5mm-3.5mm.

2. The grinding wheel assembly of claim 1, wherein, The angle of the first acute angle is 45°-60°, and the angle of the second acute angle is 60°-85°.

3. The grinding wheel assembly of claim 2, wherein, The projection of the fourth grinding surface on the top surface of the second grinding portion has a width of x4, and the projection of the fifth grinding surface on the top surface of the second grinding portion has a width of x5, x4 is equal to the sum of the width of the projection of the first grinding surface on the top surface of the first grinding portion and the width of the projection of the second grinding surface on the top surface of the first grinding portion, and the sum of x4 and x5 is 2.5mm-3.5mm.

4. The grinding wheel assembly of claim 1, wherein, The angle of the third acute angle is 45°-60°.

5. The grinding wheel assembly of claim 1, wherein, The roughness of the first grinding surface and the second grinding surface is greater than the roughness of the fourth grinding surface and the fifth grinding surface.

6. The grinding wheel assembly of claim 1, wherein, The first grinding wheel for installation on a chamfering machine comprises a cylindrical first body portion and a first grinding portion formed on the outer peripheral surface of the first body portion, the top surface of the first grinding portion is a plane perpendicular to the axis of the first body portion, the bottom surface of the first grinding portion is partially inclined away from the top surface of the first grinding portion and forms a first grinding surface and a second grinding surface connected to the first grinding surface at one end, the other end of the second grinding surface is connected to the first body portion; the distance from the end of the first grinding surface close to the first body portion to the top surface of the first grinding portion is less than the distance from the end of the second grinding surface close to the first body portion to the top surface of the first grinding portion, the first grinding surface has a first acute angle with the axis direction of the first body portion, the second grinding surface has a second acute angle with the axis direction of the first body portion, and the first acute angle is smaller than the second acute angle.

7. The grinding wheel assembly of claim 1, wherein, ​ 8. A wafer manufacturing method performed based on the grinding wheel assembly according to claim 1, characterized by, ​ A wafer raw piece is provided, which includes a support piece and a device piece raw piece bonded to each other; The wafer raw piece is placed at the first grinding wheel, the device piece raw piece is arranged towards the bottom surface of the first grinding part, and at least the first grinding surface and the second grinding surface grind the device piece raw piece, so that the device piece raw piece is partially ground and a first notch matching the first grinding surface and the second grinding surface is formed; The wafer raw piece after being ground by the first grinding wheel is placed at the second grinding wheel, the first notch is arranged towards the bottom surface of the second grinding part, and the fourth grinding surface and the fifth grinding surface grind the device piece raw piece at a position close to the first notch and form a second notch matching the fourth grinding surface and the fifth grinding surface; Edge single surface etching is performed on the ground wafer raw piece.

9. The wafer manufacturing method according to claim 8, wherein When the first grinding wheel is used to perform the grinding operation, the first grinding wheel rotates at a speed of 8000 rpm to 9000 rpm, and the wafer raw piece rotates at a linear speed of 10 mm / s to 25 mm / s.

10. The wafer manufacturing method according to claim 9, wherein When the second grinding wheel is used to perform the grinding operation, the second grinding wheel rotates at a speed of 8000 rpm to 9000 rpm, and the wafer raw piece rotates at a linear speed of 10 mm / s to 15 mm / s.

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