Wafer polishing method, wafer polishing system, and wafer

Abstract

The application discloses a wafer grinding method, a wafer grinding system and a wafer, and relates to the technical field of wafer grinding, in particular to a wafer grinding method, a wafer grinding system and a wafer. The wafer grinding method comprises the following steps: S1, the center axis of a grinding wheel and the center axis of a wafer are arranged in parallel, the axial side of the grinding wheel is provided with a grinding surface, and the axial side of the wafer is provided with a surface to be ground; S2, the grinding wheel rotates around the center axis thereof, one of the wafer and the grinding wheel moves linearly along a preset path relative to the other, the grinding surface grinds the surface to be ground, and the grinding trace of the wafer comprises a plurality of arc lines arranged along the radial direction of the wafer in sequence, wherein the center of the grinding wheel is located on the center axis of the grinding wheel, the center of the wafer is located on the center axis of the wafer, and the preset path is perpendicular to the center axis of the grinding wheel. According to the wafer grinding method, the interference of the grinding trace on wafer defect detection can be reduced.

Description

Technical Field

[0001] This invention relates to the field of wafer fabrication, and in particular to a wafer grinding method, a wafer grinding system, and a wafer wafer. Background Technology

[0002] In related technologies, wafer polishing systems typically employ horizontally positioned polishing discs and a support stage. The support stage holds the wafer in place, and the axes of the polishing discs and the support stage are parallel. The polishing discs and the support stage rotate in the same direction. The rotating polishing discs move axially downwards to polish the rotating wafer to a specified thickness, resulting in circular rotational symmetry of the polishing marks on the wafer. However, the crystal growth defects on the wafer also exhibit circular rotational symmetry, causing the polishing marks to interfere with the detection of crystal growth defects. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a wafer grinding method that can reduce the interference of grinding marks on wafer defect detection.

[0004] The present invention also proposes a wafer polishing system.

[0005] The present invention also proposes a wafer.

[0006] According to a first aspect of the present invention, a wafer polishing method includes the following steps: S1, the central axis of a polishing wheel and the central axis of a wafer are arranged parallel to each other, the polishing wheel has a polishing surface on one axial side, and the wafer has a surface to be polished on one axial side; S2, the polishing wheel rotates about its central axis, one of the wafer and the polishing wheel moves linearly relative to the other along a preset path, the polishing surface polishes the surface to be polished, so that the polishing marks on the wafer include a plurality of arcs arranged sequentially along the radial direction of the wafer, wherein the center of the polishing wheel is located on the central axis of the polishing wheel, the center of the wafer is located on the central axis of the wafer, and the preset path is perpendicular to the central axis of the polishing wheel.

[0007] According to the wafer grinding method of the present invention, during the grinding process, one of the wafer and the grinding wheel moves linearly along a preset path relative to the other, and the preset path is perpendicular to both the central axis of the grinding wheel and the central axis of the wafer. This allows the wafer or the grinding wheel to grind the surface to be ground in a radial feed manner, thereby making the form of the grinding marks different from the distribution form of crystal growth defects, and thus reducing the interference of grinding marks on wafer defect detection.

[0008] In some embodiments, the wafer moves along the preset path so that the center of the wafer has a first movement trajectory, the first movement trajectory being intersected by the central axis of the grinding wheel.

[0009] In some embodiments, a notch is formed on the outer peripheral wall of the wafer, and on the cross-section of the wafer, the line connecting the orthographic projection of the notch and the orthographic projection of the wafer center forms an angle α with the orthographic projection of the first movement trajectory, where 0°≤α≤45°.

[0010] In some embodiments, the wafer moves along the preset path so that the center of the wafer has a first movement trajectory, the first movement trajectory being eccentric to the central axis of the grinding wheel.

[0011] In some embodiments, the distance between the first moving trajectory and the central axis of the grinding wheel is L, and the radius of the wafer is R, where L ≤ R.

[0012] In some embodiments, the grinding wheel moves along the preset path so that the center of the grinding wheel has a second moving trajectory, and on the cross-section of the wafer, the orthographic projection of the wafer center is located on the orthographic projection of the second moving trajectory, or the orthographic projection of the wafer center and the orthographic projection of the second moving trajectory are spaced apart.

[0013] According to a second aspect of the present invention, a wafer polishing system includes: a polishing wheel having a polishing surface on one axial side; a first driving mechanism for driving the polishing wheel to rotate about a central axis of the polishing wheel; a support platform for fixing a wafer such that the central axis of the wafer is adapted to be parallel to the central axis of the polishing wheel; and a second driving mechanism for driving at least one of the support platform and the polishing wheel to move such that one of the wafer and the polishing wheel moves linearly relative to the other along a predetermined path, wherein the center of the polishing wheel is located on the central axis of the polishing wheel, the center of the wafer is located on the central axis of the wafer, and the predetermined path is perpendicular to the central axis of the polishing wheel.

[0014] According to the wafer polishing system of the present invention, at least one of the carrier stage and polishing wheel 1 is moved by setting a second driving mechanism, so that the first moving trajectory of the center of the wafer driven by the carrier stage and / or the second moving trajectory of the center of the polishing wheel are perpendicular to the central axis of the polishing wheel. This allows the wafer or the polishing wheel to polish the surface to be polished in a radial feeding manner, thereby making the form of polishing marks different from the distribution form of crystal growth defects, and thus reducing the interference of polishing marks on wafer defect detection.

[0015] In some embodiments, the grinding wheel includes a grinding disc and a plurality of grinding teeth, wherein the plurality of grinding teeth are disposed on the same side of the grinding disc along the axial direction and are spaced apart along the circumferential direction of the grinding disc.

[0016] According to a third aspect of the present invention, the wafer has grinding marks on its surface, the grinding marks including a plurality of sub-marks arranged sequentially along the radial direction of the wafer, the sub-marks being arcs connecting two points spaced apart circumferentially along the outer periphery of the wafer.

[0017] According to an embodiment of the present invention, the grinding marks on the surface of the wafer are multiple arcs arranged sequentially along the radial direction of the wafer. Since the form of the grinding marks is significantly different from that of crystal growth defects, the interference of the grinding marks on wafer inspection is reduced, and the accuracy of inspection is improved.

[0018] In some embodiments, the outer peripheral wall of the wafer has a notch, and a plurality of the sub-traces are arranged sequentially along the line connecting the wafer center and the notch.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0021] Figure 1 This is a schematic diagram of a wafer polishing system according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of a wafer polishing system according to another embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of a wafer polishing system according to yet another embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of a wafer according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of a wafer according to another embodiment of the present invention;

[0026] Figure 6 This is a schematic flowchart of the wafer grinding method according to the present invention.

[0027] Figure label:

[0028] Wafer Grinding System 100

[0029] Grinding wheel 1, grinding surface 1a, grinding disc 11, grinding teeth 12

[0030] First drive mechanism 2, support platform 3, second drive mechanism 4

[0031] Wafer 5, surface to be ground 5a, sub-mark 5b, wafer 51, notch 52. Detailed Implementation

[0032] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0033] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0034] Hereinafter, with reference to the accompanying drawings, a wafer polishing method according to an embodiment of the present invention will be described.

[0035] like Figure 1 and Figure 6 As shown, the wafer grinding method includes the following steps: S1, the central axis of the grinding wheel 1 and the central axis of the wafer 5 are arranged parallel to each other. The grinding wheel 1 has a grinding surface 1a on one axial side, and the wafer 5 has a surface 5a to be ground on one axial side; S2, the grinding wheel 1 rotates around its own central axis, and one of the wafer 5 and the grinding wheel 1 moves linearly relative to the other along a preset path. The grinding surface 1a grinds the surface 5a to be ground to grind the wafer 5 to a specified thickness, so that the grinding marks on the wafer 5 include multiple arcs arranged sequentially along the radial direction of the wafer 5. The center of the grinding wheel 1 is located on the central axis of the grinding wheel 1, the center of the wafer 5 is located on the central axis of the wafer 5, and the preset path is perpendicular to the central axis of the grinding wheel 1.

[0036] As can be seen, in step S2, the wafer 5 and the grinding wheel 1 can be arranged sequentially along the axial direction, with the grinding surface 1a located on the side of the grinding wheel 1 facing the wafer 5, and the surface 5a to be ground located on the side of the wafer 5 facing the grinding wheel 1. Furthermore, in step S2, wafer 5 moves linearly along a preset path, so that the center of wafer 5 has a first moving trajectory, which is perpendicular to the central axis of grinding wheel 1, while the center of grinding wheel 1 remains stationary, i.e., grinding wheel 1 does not move along the preset path, thereby achieving relative movement between grinding wheel 1 and wafer 5, and thus achieving grinding; or grinding wheel 1 moves linearly along a preset path, so that the center of grinding wheel 1 has a second moving trajectory, which is perpendicular to the central axis of grinding wheel 1, while the center of wafer 5 remains stationary, i.e., wafer 5 does not move along the preset path, which can also achieve relative movement between grinding wheel 1 and wafer 5, ensuring grinding; or, wafer 5 moves linearly along a corresponding preset path, and grinding wheel 1 moves linearly along a corresponding preset path, so that the center of wafer 5 has a first moving trajectory and the center of grinding wheel 1 has a second moving trajectory, the first moving trajectory and the second moving trajectory can be parallel, and both the first moving trajectory and the second moving trajectory are perpendicular to the central axis of grinding wheel 1.

[0037] In step S2, when the wafer 5 and the grinding wheel 1 move in a straight line along the corresponding preset path, the moving direction of the wafer 5 is opposite to that of the grinding wheel 1, or the moving direction of the wafer 5 is the same as that of the grinding wheel 1, and the moving speed of the wafer 5 is different from that of the grinding wheel 1.

[0038] Therefore, both the first moving trajectory of wafer 5 and the second moving trajectory of grinding wheel 1 extend into a straight line segment along the preset path, and the preset path is also perpendicular to the central axis of grinding wheel 1, so that the grinding marks on wafer 5 after grinding include multiple arcs arranged sequentially along the radial direction of wafer 5.

[0039] It is understandable that the depth (macro or micro) of the grinding marks is related to the relative moving speed of the wafer 5 and the grinding wheel 1 during the grinding process, as well as the rotation speed of the grinding wheel 1; for example, if the relative moving speed of the wafer 5 and the grinding wheel 1 is relatively small during the grinding process, the grinding marks will be relatively shallow.

[0040] In some other technologies, during wafer grinding, the wafer rotates around its own central axis, and the grinding wheel also rotates around its own central axis. The central axis of the wafer and the central axis of the grinding wheel are parallel, and the position of the wafer remains unchanged along its axial direction. The grinding wheel feeds along its axial direction to grind the surface to be ground, resulting in the final grinding marks on the wafer exhibiting a circular arc rotational symmetry pattern. Defects generated during crystal growth also exhibit a roughly circular arc rotational symmetry distribution, causing the grinding marks on the wafer to interfere with the detection of crystal growth defects, making it impossible to effectively distinguish between grinding marks and crystal growth defects.

[0041] In this application, the wafer 5 and / or the grinding wheel 1 move linearly along a preset trajectory, and the preset path is perpendicular to the central axis of the grinding wheel 1. The movement trajectory of the center of the wafer 5 and / or the movement trajectory of the center of the grinding wheel 1 are perpendicular to the central axis of the grinding wheel 1, realizing the grinding feed. One of the wafer 5 and the grinding wheel 1 is radially fed relative to the other of the wafer 5 and the grinding wheel 1 so that the grinding surface 1a is ground on the surface 5a to be ground. This makes the grinding marks on the wafer 5 appear as multiple arcs arranged sequentially along the radial direction of the wafer 5, roughly in an axisymmetric pattern. This makes the grinding marks on the wafer 5 clearly distinguishable from crystal growth defects, thereby reducing the interference of the grinding marks on the subsequent defect detection of the wafer 5 and ensuring the accuracy of defect detection.

[0042] According to the wafer grinding method of the present invention, during the grinding process, one of the wafer 5 and the grinding wheel 1 moves linearly relative to the other along a preset path, and the preset path is perpendicular to the central axis of the grinding wheel 1. This allows the wafer 5 or the grinding wheel 1 to grind the grinding surface 1a in a radial feed manner, thereby making the form of the grinding marks different from the distribution form of the crystal growth defects, and thus reducing the interference of the grinding marks on the defect detection of the wafer 51.

[0043] In some embodiments, such as Figure 3 As shown, in step S2, the wafer 5 moves along a preset path so that the center of the wafer 5 has a first moving trajectory. The first moving trajectory intersects with the central axis of the grinding wheel 1. During the grinding process, the central axis of the wafer 5, the central axis of the grinding wheel 1, and the first moving trajectory of the center of the wafer 5 are in the same plane. This makes the orthographic projection of the first moving trajectory of the center of the wafer 5 on the cross-section of the wafer 5 collinear with the orthographic projection of the center of the grinding wheel 1. This helps to reduce the required diameter of the grinding wheel 1. For example, the diameter of the grinding wheel 1 is greater than or equal to the diameter of the wafer 5.

[0044] In some embodiments, such as Figure 3 and Figure 4 As shown, a notch 52 (or V-groove) is formed on the outer peripheral wall of wafer 5. On the cross-section of wafer 5, the line connecting the orthographic projection of notch 52 and the orthographic projection of the center of wafer 5 forms an angle α with the orthographic projection of the first moving trajectory, where 0°≤α≤45°. This is to reduce the overlap between the grinding marks of wafer 5 and notch 52, and to avoid the grinding marks of wafer 5 coinciding with the notch crystal orientation, thereby reducing the risk of wafer 5 breaking.

[0045] Compared to some of the aforementioned technologies, where the grinding wheel feeds the wafer axially, causing the grinding marks on the wafer to coincide with the notch crystal orientation, and the notch is the cleavage plane of wafer 5, which is the direction where the internal bonding force of the crystal is weakest, it is most likely to break after being subjected to force, easily causing wafer breakage. The wafer grinding method of this application can make the grinding marks on wafer 5 offset from the notch crystal orientation, which is conducive to improving the fracture strength of wafer 5 and reducing the breakage rate.

[0046] In some embodiments, such as Figure 2 As shown, in step S2, the wafer 5 moves along a preset path so that the center of the wafer 5 has a first moving trajectory. The first moving trajectory is set out to be opposite to the central axis of the grinding wheel 1. Therefore, during the grinding process, the central axis of the wafer 5, the central axis of the grinding wheel 1, and the first moving trajectory of the center of the wafer 5 are not located in the same plane. This helps to reduce the alignment accuracy requirements of the wafer 5, the grinding wheel 1, and the preset direction, and facilitates the simplification of the operation requirements of the wafer grinding method.

[0047] In some embodiments, such as Figure 2 As shown, the distance between the first moving trajectory and the central axis of the grinding wheel 1 is L, and the radius of the wafer 5 is R, where L ≤ R, so that the grinding wheel 1 can effectively grind the entire wafer 5 in one feed process. At the same time, it avoids the distance L between the first moving trajectory of the wafer 5 and the central axis of the grinding wheel 1 being too large, which would require increasing the diameter of the grinding wheel 1 to grind the wafer 5, thereby improving the applicability of the wafer grinding system 100. In this case, the diameter of the grinding wheel 1 can be larger than the diameter of the wafer 5.

[0048] In some embodiments, the grinding wheel 1 moves along a preset path so that the center of the grinding wheel 1 has a second moving trajectory. On the cross-section of the wafer 5, the orthographic projection of the center of the wafer 5 is located on the orthographic projection of the second moving trajectory, or the orthographic projection of the center of the wafer 5 and the orthographic projection of the second moving trajectory are spaced apart. Then the second moving trajectory of the center of the grinding wheel 1 intersects or is not on the same plane as the central axis of the wafer 5, so that in step S2 the grinding wheel 1 moves toward the wafer 5 to achieve feeding, so that the grinding surface 1a grinds the surface 5a to be ground, so as to grind the wafer 5 to a specified thickness.

[0049] In some embodiments, the second moving trajectory of the center of the grinding wheel 1 intersects with the central axis of the wafer 5, and a notch 52 is formed on the outer peripheral wall of the wafer 5. On the cross-section of the wafer 5, the line connecting the orthographic projection of the notch 52 and the orthographic projection of the center of the wafer 5 forms an angle β with the orthographic projection of the second moving trajectory of the center of the grinding wheel 1, where 0°≤β≤45°, so as to reduce the overlap of the grinding marks on the wafer 5 with the notch 52 and reduce the risk of the wafer 5 breaking.

[0050] In some embodiments, the second moving trajectory of the center of the grinding wheel 1 is out of plane with the central axis of the wafer 5, and the distance between the second moving trajectory and the central axis of the wafer 5 is L', the radius of the wafer 5 is R, and L'≤R, so that the grinding wheel 1 can effectively grind the entire wafer 5 in one feed process, while also helping to reduce the diameter of the grinding wheel 1 and improve the applicability of the wafer grinding system 100. In this case, the diameter of the grinding wheel 1 can be larger than the diameter of the wafer 5.

[0051] Of course, this application is not limited to this; in other embodiments, the center of the wafer 5 has a first moving trajectory and the center of the grinding wheel 1 has a second moving trajectory. The first moving trajectory of the center of the wafer 5 may intersect with the central axis of the grinding wheel 1. At this time, the second moving trajectory of the grinding wheel 1 also intersects with the central axis of the wafer 5; or, the first moving trajectory of the center of the wafer 5 is arranged in a different plane from the central axis of the grinding wheel 1. At this time, the second moving trajectory of the grinding wheel 1 is also arranged in a different plane from the central axis of the wafer 5.

[0052] It should be noted that in the description of this application, the "central axis" is a straight line.

[0053] According to a second aspect of the present invention, a wafer polishing system 100 includes a polishing wheel 1, a first driving mechanism 2, a support platform 3, and a second driving mechanism 4. The polishing wheel 1 has a polishing surface 1a on one axial side. The first driving mechanism 2 is used to drive the polishing wheel 1 to rotate about the central axis of the polishing wheel 1, for example, clockwise or counterclockwise. The support platform 3 is used to fix the wafer 5 so that the central axis of the wafer 5 is adapted to be parallel to the central axis of the polishing wheel 1. The second driving mechanism 4 is used to drive at least one of the support platform 3 and the polishing wheel 1 to move so that one of the wafer 5 and the polishing wheel 1 moves linearly relative to the other along a preset path, and the center of the wafer 5 and / or the center of the polishing wheel 1 has a movement trajectory, so that the polishing surface 1a polishes the surface 5a to be polished.

[0054] The center of the grinding wheel 1 is located on the central axis of the grinding wheel 1, the center of the wafer 5 is located on the central axis of the wafer 5, and the preset path is perpendicular to the central axis of the grinding wheel 1, or the preset path is perpendicular to the central axis of the grinding wheel 1.

[0055] It can be seen that the second driving mechanism 4 can be configured as follows: 1. The second driving mechanism 4 is used to drive the support platform 3 to move, so that the support platform 3 drives the wafer 5 to move linearly relative to the grinding wheel 1 along a preset path. At this time, the wafer 5 moves along the preset path so that the center of the wafer 5 has a first moving trajectory, while the second driving mechanism 4 does not drive the grinding wheel 1 to move; 2. The second driving mechanism 4 is used to drive the grinding wheel 1 to move, so that the grinding wheel 1 moves linearly relative to the support platform 3 along a preset path. At this time, the center of the grinding wheel 1 has a second moving trajectory, while the second driving mechanism 4 does not drive the support platform 3 to move; 3. The second driving mechanism 4 is used to drive the support platform 3 and the grinding wheel 1 to move respectively, so that one of the grinding wheel 1 and the support platform 3 moves linearly relative to the other along a preset path. At this time, the center of the wafer 5 and the center of the grinding wheel 1 each have a moving trajectory, and the first moving trajectory of the center of the wafer 5 and the second moving trajectory of the center of the grinding wheel 1 can be parallel.

[0056] When the second driving mechanism 4 is used to drive the support platform 3 and the grinding wheel 1 to move respectively, the wafer 5 and the grinding wheel 1 move in a straight line along a preset path. The moving direction of the wafer 5 is opposite to the moving direction of the grinding wheel 1, or the moving direction of the wafer 5 is the same as the moving direction of the grinding wheel 1 and the moving speed of the wafer 5 is different from the moving speed of the grinding wheel 1.

[0057] Therefore, both the first moving trajectory of wafer 5 and the second moving trajectory of polishing wheel 1 extend along the preset path as straight segments. The preset path is also perpendicular to the central axis of polishing wheel 1. This results in the polishing marks on wafer 5 after polishing being arranged in multiple arcs along the radial direction of wafer 5. This makes the polishing marks on wafer 5 clearly different from crystal growth defects, thereby reducing the interference of polishing marks on subsequent defect detection of wafer 5 and ensuring the accuracy of defect detection.

[0058] According to the wafer polishing system 100 of the present invention, at least one of the support stage 3 and polishing wheel 1 is moved by the second driving mechanism 4, so that one of the support stage 3 and polishing wheel 1 moves linearly relative to the other along a preset path, and the first moving trajectory of the center of the wafer 5 and / or the second moving trajectory of the center of the polishing wheel 1 are perpendicular to the central axis of the polishing wheel 1, so that the wafer 5 or the polishing wheel 1 polishes the polishing surface 1a to be polished in a radial feed manner, thereby making the form of polishing marks different from the distribution form of crystal growth defects, and thus reducing the interference of polishing marks on the defect detection of wafer 51.

[0059] Optionally, the support platform 3 can be configured to swing relative to the grinding wheel 1 to change the angle between the central axis of the wafer 5 and the central axis of the grinding wheel 1. In this case, during grinding, the support platform 3 can be adjusted so that the central axis of the wafer 5 is parallel to the central axis of the grinding wheel 1. Of course, the support platform 3 can also be configured not to swing relative to the grinding wheel 1, in which case the central axis of the wafer 5 and the central axis of the grinding wheel 1 always remain parallel.

[0060] In some embodiments, such as Figure 1 As shown, the grinding wheel 1 includes a grinding disk 11 and a plurality of grinding teeth 12. The plurality of grinding teeth 12 are located on the same side of the axial direction of the grinding disk 11 and are spaced apart along the circumference of the grinding disk 11. The plurality of grinding teeth 12 grind the wafer 5 to a specified thickness as the grinding disk 11 rotates. Thus, the grinding wheel 1 has a simple structure and low cost.

[0061] In some embodiments, such as Figure 1 and Figure 3 As shown, the second driving mechanism 4 drives the support platform 3 to move, so that the support platform 3 drives the wafer 5 to move linearly relative to the grinding wheel 1 along a preset path, so that the center of the wafer 5 has a first moving trajectory, and the first moving trajectory of the center of the wafer 5 intersects with the central axis of the grinding wheel 1.

[0062] In some embodiments, such as Figure 3 As shown, the second drive mechanism 4 is configured such that the first moving trajectory of the center of the wafer 5 intersects with the central axis of the grinding wheel 1, and on the cross-section of the wafer 5, the line connecting the orthographic projection of the notch 52 on the outer peripheral wall of the wafer 5 and the orthographic projection of the center of the wafer 5 forms an angle α with the orthographic projection of the first moving trajectory of the center of the wafer 5, where 0°≤α≤45°.

[0063] In some embodiments, such as Figure 2 As shown, the second driving mechanism 4 drives the support platform 3 to move, so that the support platform 3 drives the wafer 5 to move linearly relative to the grinding wheel 1 along a preset path, so that the center of the wafer 5 has a first moving trajectory, and the first moving trajectory of the center of the wafer 5 is set out to be out of plane with the central axis of the grinding wheel 1.

[0064] In some embodiments, such as Figure 2 As shown, the second driving mechanism 4 is configured such that the first moving trajectory of the center of the wafer 5 is out of plane with the central axis of the grinding wheel 1, and the distance between the first moving trajectory of the center of the wafer 5 and the central axis of the grinding wheel 1 is L, the radius of the wafer 5 is R, and L≤R.

[0065] In some embodiments, the second driving mechanism 4 drives the grinding wheel 1 to move so that the grinding wheel 1 moves in a straight line relative to the support platform 3 along a preset path, so that the center of the grinding wheel 1 has a second moving trajectory, and the second moving trajectory of the grinding wheel 1 is intersected with the central axis of the wafer 5.

[0066] In some embodiments, the second drive mechanism 4 is configured such that the second moving trajectory of the center of the grinding wheel 1 intersects the central axis of the wafer 5, and on the cross-section of the wafer 5, the line connecting the orthographic projection of the notch 52 on the outer peripheral wall of the wafer 5 and the orthographic projection of the center of the wafer 5 forms an angle β with the orthographic projection of the second moving trajectory of the center of the grinding wheel 1, where 0°≤β≤45°.

[0067] In some embodiments, the second driving mechanism 4 drives the support platform 3 to move, so that the support platform 3 drives the wafer 5 to move linearly relative to the grinding wheel 1 along a preset path, so that the center of the wafer 5 has a second moving trajectory, and the second moving trajectory of the wafer 5 is arranged out of plane with the central axis of the grinding wheel 1.

[0068] In some embodiments, the second drive mechanism 4 is configured such that the second moving trajectory of the center of the grinding wheel 1 is out of plane with the central axis of the wafer 5, the distance between the second moving trajectory of the grinding wheel 1 and the central axis of the wafer 5 is L, the radius of the wafer 5 is R, and L≤R.

[0069] According to a third aspect embodiment of the present invention, the wafer 51 has grinding marks on its surface. The grinding marks include a plurality of sub-marks 5b arranged sequentially along the radial direction of the wafer 51. The sub-marks 5b are arcs connecting two points spaced apart circumferentially along the outer periphery of the wafer 51.

[0070] According to an embodiment of the present invention, the grinding marks on the surface of the wafer 51 are multiple arcs arranged sequentially along the radial direction of the wafer 51. Since the form of the grinding marks is significantly different from that of crystal growth defects, the interference of the grinding marks on the detection of the wafer 51 is reduced, and the accuracy of the detection is improved.

[0071] It should be noted that wafer 51 is formed by grinding wafer 5 to a specified thickness using grinding wheel 1.

[0072] In some embodiments, such as Figure 4 As shown, the outer peripheral wall of the wafer 51 has a notch 52 (or V-groove), and multiple sub-marks 5b are arranged sequentially along the line connecting the center of the wafer 51 and the notch 52. At this time, the feed direction of the wafer 51 during the grinding process is parallel to the line connecting the center of the wafer 51 and the notch 52, so that the sub-marks 5b do not coincide with the notch 52, thereby reducing the breakage rate of the wafer 51.

[0073] Of course, multiple sub-marks 5b can also be sequentially arranged along a direction forming an angle γ with the line connecting the center of wafer 51 and notch 52, where 0° < γ ≤ 45°, such as... Figure 5 As shown, this also avoids the grinding marks from coinciding with notch 52, thus reducing the breakage rate.

[0074] Furthermore, the inventors of this application conducted experiments on the radial feed grinding wafer grinding method of this application and the axial feed grinding method in related technologies. The fracture strength of various points of the wafer 51 obtained by the two grinding methods of radial feed (corresponding to the wafer grinding method of this application) and axial feed was tested, as shown in the table below. According to the experimental data, the minimum and average fracture strength of the radial feed grinding method are significantly higher than those of the axial feed grinding method. Moreover, the breakage of the wafer 52 is mainly determined by the minimum fracture strength. Therefore, the radial feed grinding wafer grinding method of this application can effectively reduce the breakage rate of the wafer 51.

[0075]

[0076] In the description of this invention, it should be understood that the terms "center," "thickness," "upper," "lower," "front," "horizontal," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0077] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0080] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A wafer grinding method, characterized in that, Includes the following steps: S1. The central axis of the grinding wheel (1) and the central axis of the wafer (5) are arranged parallel to each other. The grinding wheel (1) has a grinding surface (1a) on one axial side, and the wafer (5) has a grinding surface (5a) on one axial side. S2. The grinding wheel (1) rotates around its central axis. One of the wafer (5) and the grinding wheel (1) moves in a straight line relative to the other along a preset path. The grinding surface (1a) grinds the surface to be ground (5a). The grinding marks on the wafer (5) include multiple arcs arranged sequentially along the radial direction of the wafer (5). The center of the grinding wheel (1) is located on the central axis of the grinding wheel (1), and the center of the wafer (5) is located on the central axis of the wafer (5). The preset path is perpendicular to the central axis of the grinding wheel (1) so that the form of the grinding marks on the wafer (5) is different from the distribution form of crystal growth defects. The wafer (5) moves along the preset path so that the center of the wafer (5) has a first moving trajectory. The first moving trajectory is skewed from the central axis of the grinding wheel (1). A notch (52) is formed on the outer peripheral wall of the wafer (5). On the cross-section of the wafer (5), the line connecting the orthographic projection of the notch (52) and the orthographic projection of the center of the wafer (5) forms an angle α with the orthographic projection of the first moving trajectory, where 0° < α ≤ 45°, to reduce the overlap of grinding marks on the wafer (5) with the notch (52); or, The grinding wheel (1) moves along the preset path so that the center of the grinding wheel (1) has a second moving trajectory. On the cross-section of the wafer (5), the orthographic projection of the center of the wafer (5) and the orthographic projection of the second moving trajectory are spaced apart. A notch (52) is formed on the outer peripheral wall of the wafer (5). On the cross-section of the wafer (5), the line connecting the orthographic projection of the notch (52) and the orthographic projection of the center of the wafer (5) forms an angle β with the orthographic projection of the second moving trajectory, 0°<β≤45, so as to reduce the grinding marks of the wafer (5) from coinciding with the notch (52).

2. The wafer grinding method according to claim 1, characterized in that, The distance between the first moving trajectory and the central axis of the grinding wheel (1) is L, and the radius of the wafer (5) is R, where L≤R.

3. A wafer (51), characterized in that, Wafers are processed using the wafer grinding method according to any one of claims 1-2. The surface of the wafer (51) has grinding marks, which include a plurality of sub-marks (5b) arranged sequentially along the radial direction of the wafer (51). The sub-marks (5b) are arcs connecting two points spaced apart circumferentially along the outer periphery of the wafer (51). The outer peripheral wall of the wafer (51) has a notch (52), and the sequential arrangement direction of the plurality of sub-marks (5b) forms an angle γ with the line connecting the center of the wafer (51) and the notch (52), 0°<γ≤45°, so as to avoid the grinding marks coinciding with the notch (52).

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