Substrate processing method and substrate for reducing deformation stress

Abstract

The application provides a substrate processing method and a substrate capable of reducing deformation stress, comprising the following steps: cutting a crystal bar into a wafer, and grinding the wafer to improve the flatness of the wafer; using a slotting component to form a plurality of first grooves parallel to a first direction on a first surface of the wafer, the first direction being parallel to the direction of the flat edge of the wafer, the plurality of first grooves being arranged at intervals in a first radial direction of the wafer, and the plurality of first grooves being arranged along the first radial direction to cover the first surface of the wafer; using the slotting component to form a plurality of second grooves perpendicular to the first grooves on the first surface of the wafer, the plurality of second grooves being arranged at intervals in a second radial direction of the wafer, and the plurality of second grooves being arranged along the second radial direction to cover the first surface of the wafer; performing high-temperature annealing on the wafer with the first grooves and the second grooves; and using a polishing device to polish a second surface of the wafer with the first grooves and the second grooves. The method reduces the warping and deformation degree of the wafer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to a substrate processing method capable of reducing deformation stress and a substrate. BACKGROUND

[0002] With the progress of science and technology, the demand for chips at home and abroad is rising. In the context of fierce competition, the improvement of quality and the uniformity of products are crucial. In the LED industry, the sapphire substrate used is made by crystal cutting, grinding, polishing and other processing. When the sapphire crystal is cut, the diamond wire simultaneously causes brittle damage to the workpiece crystal bar, the crystal is stressed and extruded, and the interaction between ions changes, thereby causing uneven surface and surface stress that is difficult to eliminate. The method for eliminating surface damage and stress residue after wire cutting is generally grinding processing. Grinding includes single-sided grinding and double-sided grinding processing. Double-sided grinding occupies the main market, and its advantages are: high double-sided processing efficiency, small grinding resistance and no damage to the wafer workpiece, and easy control of the thickness tolerance of the processed product.

[0003] Double-sided grinding powder uses B4C (boron carbide) or SiC (silicon carbide) to achieve a certain removal amount, remove the wire cutting marks, and also improve the thickness consistency and reduce the degree of warping after cutting. However, the surface damage layer after grinding still has residual stress. The existing process technology introduces annealing to remove surface stress and eliminate stress on both sides. However, after copper throwing and polishing processes are performed on the wafer, a large stress difference between the polished surface and the unpolished surface of the wafer is caused, which further causes the substrate wafer to bend or deform, thereby affecting the quality of the substrate. Therefore, how to reduce the degree of warping and deformation of the wafer is a technical problem to be solved. SUMMARY

[0004] Therefore, the present application provides a substrate processing method capable of reducing deformation stress and a substrate to solve one or more problems in the prior art.

[0005] According to one aspect of the present application, a substrate processing method capable of reducing deformation stress is disclosed, the method comprising:

[0006] cutting a crystal bar into a wafer and grinding the wafer to improve the flatness of the wafer;

[0007] absorbing the ground wafer on a vacuum seat on a stage, using a slotting component to open a plurality of first grooves parallel to a first direction on a first surface of the wafer, the first direction being parallel to the flat edge direction of the wafer, a plurality of the first grooves being arranged at intervals in a first radial direction of the wafer, and a plurality of the first grooves being distributed along the first radial direction on the first surface of the wafer;

[0008] utilizing the grooving component to groove a plurality of second grooves on the first surface of the wafer, the plurality of second grooves being arranged in a second radial direction of the wafer, and the plurality of second grooves being arranged in the second radial direction to cover the first surface of the wafer;

[0009] performing high-temperature annealing on the wafer with the first grooves and the second grooves;

[0010] utilizing a polishing device to polish a second surface of the wafer with the first grooves and the second grooves, the second surface being opposite to the first surface of the wafer.

[0011] In some embodiments of the present application, the grooving component is a grooving grinding wheel, and the grooving grinding wheel comprises a plurality of abrasive rings arranged in parallel and at intervals, each of the abrasive rings being sleeved on an outer circumferential surface of the grooving grinding wheel.

[0012] In some embodiments of the present application, the abrasive rings are trapezoidal in cross-sectional shape on a plane passing through the axis of the grooving grinding wheel, and the first grooves and the second grooves are trapezoidal in cross-sectional shape.

[0013] In some embodiments of the present application, the top width of the trapezoid ranges from 500±20um, the bottom width of the trapezoid ranges from 1000um±20um, the height of the trapezoid ranges from 50±20um, and the interval between two adjacent abrasive rings of the grooving grinding wheel ranges from 2300um±20um.

[0014] In some embodiments of the present application,

[0015] utilizing the grooving component to groove a plurality of first grooves in parallel with the first direction on the first surface of the wafer, comprising:

[0016] utilizing the grooving component to rotate at a first rotating speed and move along the first direction to groove a plurality of first grooves in parallel with the first direction on the first surface of the wafer; and / or

[0017] utilizing the grooving component to groove a plurality of second grooves perpendicular to the first grooves on the first surface of the wafer, comprising:

[0018] rotating the wafer by 90° or 270°, utilizing the grooving component to rotate at a first rotating speed and move along the first direction to groove a plurality of second grooves perpendicular to the first grooves on the first surface of the wafer.

[0019] In some embodiments of the present application, the first rotating speed ranges from 2000rpm to 2500rpm, and the unit area lapping time ranges from 5 to 10 seconds.

[0020] In some embodiments of the present application, a nickel layer is plated on the abrasive ring, and a plurality of diamond particles are attached to the surface of the abrasive ring.

[0021] In some embodiments of the present application, the wafer is polished, including:

[0022] The wafer is polished on both sides.

[0023] According to another aspect of the present application, there is also provided a substrate with reduced deformation stress, which is processed by the substrate processing method with reduced deformation stress as claimed in any one of claims 1 to 8.

[0024] In some embodiments of the present application, the number of the first grooves on the substrate is 33, and the number of the second grooves is 34.

[0025] The substrate processing method with reduced deformation stress and the substrate disclosed in the present application use a grooving component to open a plurality of first grooves and a plurality of second grooves on the back surface of the wafer (the surface opposite to the polishing surface), the first grooves and the second grooves are arranged vertically, and the plurality of first grooves and the plurality of second grooves are arranged along a first radial direction and a second radial direction respectively to cover the back surface of the wafer, that is, the back surface of the wafer is divided into a plurality of unit cells by the first grooves and the second grooves; through the above process steps, the stress on the back surface of the wafer is reduced during polishing, thereby ensuring the uniformity of the stress on the polished surface and the unpolished surface of the wafer, and further relieving the warping and deformation degree of the wafer, and ensuring the flatness of the substrate product.

[0026] Additional advantages, objects, and features of the application will be set forth in part by the description that follows, and will become apparent to those skilled in the art upon examination of the following detailed description and drawings in which

[0027] Those skilled in the art will appreciate that the objects and advantages of the application can be implemented in a manner different than described above and that the above described embodiments are merely illustrative of the principles of the application. The present application should be construed to encompass all such variations that fall within the scope of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present application and, together with the description given below, serve to explain the principles of the application. The components in the drawings are not to scale, with emphasis instead being placed upon illustrating the principles of the application. For purposes of clarity and understanding, it is expressly intended that some portions of the drawings be shown exaggerated in scale, or out of proportion, to illustrate aspects of the application. In the drawings:

[0029] Figure 1 A flow chart of a substrate processing method for reducing deformation stress according to an embodiment of the present application.

[0030] Figure 2 A flow chart of a substrate processing method for reducing deformation stress according to another embodiment of the present application.

[0031] Figure 3 A structure diagram of a slotting component according to an embodiment of the present application.

[0032] Figure 4 A structure diagram of a substrate for reducing deformation stress according to an embodiment of the present application.

[0033] Figure 5 A partial structure diagram of a substrate. Figure 4

[0034] A partial SEM scanning electron microscope picture of a substrate. Figure 6 Figure 5 A slotting device for slotting a substrate according to an embodiment of the present application.

[0035] Figure 7 A comparison diagram of bending and deformation degrees of a substrate of the prior art and a substrate of the present application in each process.

[0036] DETAILED DESCRIPTION Figures 8a to 8d In order to make the objects, technical solutions and advantages of embodiments of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the drawings. Herein, the schematic embodiments of the present application and the descriptions thereof are used to explain the present application, but are not used as a limitation to the present application.

[0037] Herein, it should be noted that, in order to avoid the present application being obscured by unnecessary details, only the structures and / or processing steps closely related to the solutions according to the present application are shown in the drawings, and other details not closely related to the present application are omitted.

[0038] It should be emphasized that the terms "comprise / comprising" when used in this specification are taken to specify the presence of stated features, elements, steps or components but do not preclude the presence or addition of one or more other features, elements, steps, components or groups thereof.

[0039] In the following, embodiments of the present application will be described with reference to the drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0040]

[0041] Figure 1 ​​This is a schematic flowchart of a substrate processing method for reducing deformation stress according to an embodiment of the present invention, as shown below. Figure 1 As shown, the substrate processing method that can reduce deformation stress includes at least steps S10 to S50.

[0042] Step S10: Cut the crystal rod into wafers and grind the wafers to improve the flatness of the wafers.

[0043] In this step, the crystal ingot is cut into wafers using a crystal ingot cutting device. Specifically, a thin, annular saw blade with diamond particles embedded in its inner edge can be used to cut the crystal ingot into wafers. Because the outer edges of the cut wafers are very sharp, to prevent chipping and damage to the wafer's strength, surface finish, and contamination particles in subsequent processes, the wafer edge shape and outer diameter can be further refined. Grinding aims to remove saw marks and damage generated during cutting, achieving the required surface finish. Wafer grinding can be performed on a wafer grinding machine. In this step, wafer grinding can be single-sided or double-sided.

[0044] Step S20: The polished wafer is adsorbed onto the vacuum seat on the stage. Multiple first grooves parallel to a first direction are opened on the first surface of the wafer using a grooving component. The first direction is parallel to the flat edge direction of the wafer. The multiple first grooves are spaced apart in the first radial direction of the wafer, and the multiple first grooves cover the first surface of the wafer along the first radial direction.

[0045] Figure 7 This is a schematic diagram of a grooving device for grooving a substrate according to an embodiment of the present invention, as shown below. Figure 7 As shown, the grooving equipment includes at least a stage 200, a vacuum seat 300, and a grooving component 100. The stage 200 and vacuum seat 300 can be existing equipment commonly used in the fabrication of wafer 001. The vacuum seat 300 is used to hold the wafer 001, while the stage 200 can rotate around its axis to adjust the angle of the wafer 001; additionally, the stage can also move along the X2 direction. Figure 7 In this design, the grooving component 100 is located above the wafer 001. For example, the grooving component 100 is a grooving grinding wheel. When grooving the wafer 001, the grooving grinding wheel located above the wafer 001 can not only rotate around its own axis, but also move horizontally. It should be understood that, in addition to a grooving grinding wheel, other grooving components such as grooving blades can also be used when grooving the wafer.

[0046] For example, the step of using the grooving component to groove a plurality of first grooves on the first surface of the wafer in parallel with the first direction comprises: using the grooving component to rotate at a first rotating speed and move along the first direction to groove a plurality of first grooves on the first surface of the wafer in parallel with the first direction. At this time, the first direction is a direction parallel with the first grooves and the flat side of the wafer, and the first direction can also be understood as a horizontal direction.

[0047] Specifically, when grooving the first grooves, the wafer is first placed on the wafer supporting table, and the flat side direction of the wafer is adjusted to be parallel with the axis of the grooving grinding wheel. The grooving grinding wheel rotates around its own axis at a rotating speed R1 (first rotating speed) to grind the wafer. The grooving grinding wheel moves along the horizontal direction in the process of rotation, and thus the grooving of the first grooves is completed. Since the width of the grooving grinding wheel is generally smaller than the diameter of the wafer, the grooving grinding wheel can pass through a plurality of reciprocating movements to make a plurality of first grooves distributed on the first surface of the wafer along the first radial direction of the wafer. In this step, the first radial direction can be understood as a direction perpendicular to the flat side of the wafer. And the plurality of first grooves distributed on the first surface of the wafer can also be understood as that the distance between the outermost first groove and the outer edge of the wafer is small enough so that a first groove cannot be further grooved.

[0048] Further, the grooving grinding wheel comprises a plurality of abrasive rings arranged in parallel and at intervals, and each of the abrasive rings is sleeved on the outer circumferential surface of the grooving grinding wheel. At this time, the grooving grinding wheel with a plurality of abrasive rings can groove a plurality of parallel first grooves on the first surface of the wafer in one reciprocating movement.

[0049] Step S30: using the grooving component to groove a plurality of second grooves on the first surface of the wafer in parallel with the first grooves, and the plurality of second grooves are arranged at intervals in the second radial direction of the wafer and distributed on the first surface of the wafer along the second radial direction.

[0050] In this step, a plurality of second grooves are further grooved on the first surface of the wafer on which the first grooves are grooved, and the direction of the second grooves is perpendicular to the direction of the first grooves, and thus the direction of the second grooves is also perpendicular to the flat side direction of the wafer. The second grooves are also grooved by the grooving grinding wheel, and preferably, the same grooving component is used to groove the first grooves and the second grooves, and at this time, the shape and size of the first grooves and the second grooves are the same.

[0051] Specifically, when the second groove is opened, the wafer is rotated 90° or 270° by the carrier under the vacuum seat, at this time, the flat edge on the wafer is perpendicular to the axis of the slotting grinding wheel, further, the slotting component is rotated at a first rotating speed, and the slotting grinding wheel moves along the first direction while rotating, so as to open a plurality of second grooves on the first surface of the wafer, which are perpendicular to the first grooves. Similarly, the slotting grinding wheel is reciprocated for multiple times, so as to make the plurality of second grooves be distributed on the first surface of the wafer along the second radial direction of the wafer; and the plurality of second grooves being distributed on the first surface of the wafer can also be understood as that the distance between the outermost second groove and the corresponding outer edge of the wafer is small enough.

[0052] Step S40: high-temperature annealing is performed on the wafer with the first grooves and the second grooves.

[0053] In order to further reduce the residual stress of the wafer, after the first grooves and the second grooves are opened on the back surface of the wafer, the wafer is further subjected to high-temperature annealing, and the annealing temperature used in this step is exemplarily 650°C.

[0054] In another embodiment, as shown in FIG. 6, before the wafer with the first grooves and the second grooves is subjected to high-temperature annealing, the wafer can be further subjected to edge chamfering. When the edge chamfering is performed, specifically, a diamond grinding wheel can be used to polish the edge of the wafer, so that the edge of the wafer is rounded and smooth, and is not easy to break. Figure 2

[0055] Step S50: the second surface of the wafer with the first grooves and the second grooves is polished by using a polishing device, and the second surface is the opposite surface of the wafer to the first surface.

[0056] Polishing is an important process of semiconductor wafer processing by removing the mechanical damage layer on the surface of the wafer and making it mirror-like by mechanical polishing, chemical polishing or chemical mechanical polishing. Chemical polishing is a purpose of polishing the surface by chemical non-selective corrosion, and the mechanical damage layer remaining on the wafer surface is small, but the surface state and geometric size precision are poor. Mechanical polishing is to achieve surface polishing by mechanical friction, which is easy to obtain a bright and mirror-like wafer surface, and the geometric size precision of the wafer is high, but the depth of the residual mechanical damage layer is affected by the type and granularity of the polishing. Chemical mechanical polishing is to make the wafer surface and the polishing material can chemically react to generate water-soluble compounds, and the chemical reaction is removed by controlled mechanical friction to achieve the purpose of polishing. In this embodiment, the wafer polishing method can be selected according to the actual application scenario.

[0057] ​In addition, when the side of the wafer on which the first grooves and the second grooves are formed is the back side of the wafer, the second surface is the front side of the wafer, and in this step, the polishing surface of the wafer is arranged opposite to the grooved surface, the tensile stress generated by the grooving of the back side of the wafer can reduce the deformation stress of the wafer, thereby inhibiting the warping and bending caused by the stress difference between the polished surface and the unpolished surface of the wafer.

[0058] The substrate processing method for reducing deformation stress includes the following steps: after the wafer is ground, the first grooves and the second grooves are formed on the first surface of the wafer by a grooving grinding wheel, so that the back side of the wafer is divided into multiple regions by the first grooves and the second grooves. The purpose is to more evenly and better reduce the stress difference between the polished surface and the unpolished line of the wafer during single-sided polishing processing of the wafer, so that the surface tensile stress is reduced, the wafer warping is avoided in the later processing, and the flatness of the substrate product is improved. On the other hand, since the tensile stress is released, the bending degree during the high-temperature operation of epitaxial crystal is lower than that of the substrate without grooving (general substrate), so that the wafer back side grooving can make the wavelength uniformity of epitaxial crystal better.

[0059] In an embodiment of the present application, the cross-sectional shape of the first grooves and the second grooves is trapezoidal, and the shape of each region on the first surface of the wafer divided by the first grooves and the second grooves is prismatic. Further, if the size of the first grooves and the second grooves is the same, and the distance between the two adjacent first grooves is equal to the distance between the two adjacent second grooves, the prismatic region divided by the first grooves and the second grooves is a right prism. Correspondingly, the cross-sectional shape of the abrasive ring in the plane passing through the axis of the grooving grinding wheel and the cross-sectional shape of the first grooves and the second grooves are also trapezoidal. Figure 3 , Figure 3 The outer surface of the grooving grinding wheel has a plurality of abrasive rings 110, and the distance between the two adjacent abrasive rings 110 is equal.

[0060] Further, the abrasive ring on the slotting grinding wheel has a trapezoidal cross-sectional shape, and the protruding height of the abrasive ring is 50±20um, the top width of the trapezoidal cross-sectional shape of the abrasive ring ranges from 500±20um, the bottom width ranges from 1000um±20um, and the distance between two adjacent abrasive rings ranges from 2300um±20um. It is understood that the size of the first groove and the second groove on the wafer back surface based on the slotting grinding wheel and the shape size of the abrasive ring on the slotting grinding wheel are consistent, i.e. the cross-sectional shape of the first groove and / or the second groove is also trapezoidal, the top width of the trapezoidal ranges from 500±20um, the bottom width ranges from 1000um±20um, the height ranges from 50±20um, and the distance between any two first grooves or any two second grooves is 2300um±20um. For example, the protruding height of the abrasive ring is 50um, the top width of the abrasive ring cross-section is 500um, the bottom width is 1000um, and the distance between the grooves is 2300um. It is understood that the number of abrasive rings on the slotting grinding wheel is not specifically limited, but the more the number of abrasive rings on the slotting grinding wheel, the higher the corresponding slotting efficiency; and the size and spacing of the abrasive rings on the slotting grinding wheel can be specifically limited according to the application scenario.

[0061] In an embodiment, the base material of the slotting grinding wheel is stainless steel, the abrasive ring on the slotting grinding wheel is plated with a nickel layer, and the surface of the abrasive ring is attached with a plurality of diamond particles. Referring to Figure 7 When slotting the wafer surface, the abrasive ring of the slotting grinding wheel is perpendicular to the wafer to ensure that the surface cutting angle and depth meet the expectations. For example, the size of the diamond particles on the slotting grinding wheel can be 500-600, and 500 can be selected. The slotting grinding wheel rotates at a first speed, and the first speed ranges from 2000rpm to 2500rpm, and the optimal surface grinding speed is 2200rpm. In addition, the grinding time per unit area ranges from 5 to 10 seconds, and the optimal grinding time is 8 seconds. In this embodiment, the size of the diamond particles on the slotting grinding wheel is selected to be 500 to better slot. When the diamond particles are small, it is difficult to achieve the expected grinding effect, and when the diamond particles are large, the diamond particles on the slotting grinding wheel are more likely to fall off. In addition, when the first speed of the slotting grinding wheel is too high, the air inflation effect will occur, so that the cutting fluid cannot flow well to the grinding surface; and when the first speed of the slotting grinding wheel is too low, the surface of the grinding surface is brittle, and the slotting efficiency is low, so that the speed of the slotting grinding wheel is between 2000rpm and 2500rpm when the wafer back surface is slotted. The speed of 2200rpm can effectively avoid the above-mentioned situation, and the speed of the slotting grinding wheel is more optimal.

[0062] Figure 7This is a schematic diagram of a grooving device for grooving a substrate according to an embodiment of the present invention, as shown below. Figure 7 As shown, the grooving equipment mainly includes a stage and a vacuum holder. The grooving wheel of this equipment rotates at a speed of R1, at which point the wheel is perpendicular and in contact with the wafer surface. During the rotation of the grooving wheel, the stage remains stationary; however, when it is necessary to change the orientation or position of the wafer, the stage can rotate at a speed of R2 and move along the X2 and Y directions. Additionally, the grooving wheel can also move along the horizontal direction X1 and the vertical direction Z. The vertical movement of the grooving wheel in the Z direction is to ensure that the abrasive ring of the grooving wheel contacts the wafer surface. The vacuum holder is the base for holding the wafer, with a vacuum pressure range of approximately -60 to -80 kPa, optimally -70 kPa.

[0063] Accordingly, the present invention also discloses a substrate that can reduce deformation stress, which is fabricated using the substrate fabrication method for reducing deformation stress as described in any of the above embodiments. Figure 4 This is a schematic diagram of the structure of a substrate that can reduce deformation stress according to an embodiment of the present invention, as shown below. Figure 4 As shown, the multiple first trenches and multiple second trenches on the first surface of the substrate are all the same in size and shape, and the spacing between any two first trenches is equal to the spacing between any two second trenches. Figure 4 The shapes of the regions on the back side of the wafer are frustum-shaped; from Figure 4 As can be seen, the surface of the trenched finished wafer has regular grooves, with multiple grooves completely distributed on the wafer surface. This allows the tensile stress on the wafer surface to be released, thereby minimizing residual stress and substrate deformation during subsequent copper polishing and polishing processes. In this embodiment, the number of first grooves on the first surface is 33, and the number of second grooves is 34. It is easy to understand that the number of first and second grooves is related to the size of the grooving abrasive ring used and the size of the wafer. Therefore, in the actual substrate processing, the number, size, and shape of each groove on the wafer can be changed according to actual needs.

[0064] Figure 5 for Figure 4 The diagram shows a partial structural schematic of the substrate, while Figure 6 for Figure 5 Partial SEM image of the substrate shown; from Figure 6 As can be seen, the surface trenches are intact after the wafer surface is trenched, without any cracking or other damage to the wafer.

[0065] To better illustrate the present application, the following compares the degree of bending and deformation of the substrate of the prior art and the substrate of the present application during each process to illustrate the technical effects of the present application. For example, the cross-sectional shape of the trench is trapezoidal, the top width of the trapezoid is 500um, the bottom width of the trapezoid is 1000um, the height of the trapezoid is 50um, and the distance between two adjacent trenches is 2300um. At this time Figures 8a to 8d The following is a comparison chart of the degree of bending and deformation of the substrate of the prior art (control group) and the substrate of the present application (experimental group) during each process; Figure 8a The following is a simulation chart of the degree of bending and deformation of the control group after annealing, from Figure 8a It can be seen from the simulation chart that the Warp (warpage) and Bow (bending) of the control group after annealing are 10.36um and -3.80um, respectively; Figure 8b The following is a simulation chart of the degree of bending and deformation of the control group after polishing, from Figure 8b It can be seen from the simulation chart that after surface copper polishing, the wafer deformation is large due to uneven stress on both sides, the Warp is 88.90um, and the Bow is 73.84um; Figure 8c The following is a simulation chart of the degree of bending and deformation of the experimental group after annealing, from Figure 8c It can be seen from the simulation chart that the Warp and Bow of the experimental group after annealing are 10.55um and -3.01um, respectively; Figure 8d The following is a simulation chart of the degree of bending and deformation of the experimental group after polishing, from Figure 8d It can be seen from the simulation chart that the Warp of the experimental group after surface copper polishing is 83.28um, and the Bow is 67.84um. From Figures 8a to 8d It can be seen that when the experimental group substrate with grooves of the present application is subjected to diamond grinding on the surface, the tensile stress caused by uneven stress on both sides can be effectively reduced, thereby reducing the degree of wafer bending.

[0066] In another embodiment, on the basis of the same quality wafer source as the above embodiment, the bottom width of the trapezoidal groove is 700±20um, the top width is 1000um±20um, the distance between the grooves is 2300±20um, and the depth of the groove is 70±20um; at this time, the warp and bow of the wafer after annealing are 10.47um and-3.39um respectively, and the warp after surface copper polishing is 84.28um and the bow is 72.81um; compared with the substrate of the above embodiment, the substrate of this embodiment has the defects of incomplete stress release, reduced wafer top end support surface, and increased probability of cracking. Therefore, the abrasive ring of the selected slotting grinding wheel is preferably limited to a protruding height of 50±20um, a top width of 500±20um, a bottom width of 1000um±20um, and a distance between adjacent two abrasive rings of 2300um±20um.

[0067] As can be seen from the above embodiments, the slotting grinding wheel performs horizontal and vertical slotting on the back of the wafer, forms several uniform squares on the effective use area of the wafer back, and the square shape is a trapezoidal block, each trapezoidal block has a length, a width, a height, and a side length that are approximately equivalent; through the slotting method, the surface roughness generated after the wafer is ground is uniformly divided regionally, so as to achieve uniform stress release as much as possible during the later processing.

[0068] For sapphire wafers after grinding process, the wafer thickness uniformity and flatness are better than that of cut wafers, so the use of trapezoidal grinding wheel can ensure the consistency of slotting depth and shape; after the wafer surface is slotted, the internal residual stress of the substrate is further released by annealing; due to the consistency of the slotting form, the deformation amount of the substrate stress is more uniform and more flat; therefore, the influence on the later process is small, the warping deformation amount is lower, and then the wafer product quality is improved. That is, the wafer slotted on the back of the wafer according to the present application has tensile stress due to slotting, which can reduce the deformation stress of the wafer and inhibit the warping and bending caused by the stress difference between the polished surface and the unpolished surface of the wafer.

[0069] It should be further noted that the exemplary embodiments mentioned in the present application describe some methods or systems based on a series of steps or devices. However, the present application is not limited to the order of the above steps, that is, the steps can be performed in the order mentioned in the embodiments, or in an order different from the embodiments, or several steps can be performed simultaneously.

[0070] Features described and / or illustrated with respect to one implementation can be used in the same manner or in a similar manner in one or more other implementations and / or in combination with or in place of features of other implementations.

[0071] The above descriptions are merely some embodiments of the present application, but are not intended to limit the present application. The embodiments of the present application can be variously changed and / or modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A substrate processing method that can reduce deformation stress, characterized in that, The method includes: The crystal rod is cut into wafers, and the wafers are ground to improve the flatness of the wafers; The polished wafer is adsorbed onto a vacuum seat on a stage. A plurality of first grooves parallel to a first direction are formed on the first surface of the wafer using a grooving component. The first direction is parallel to the flat edge direction of the wafer. The plurality of first grooves are spaced apart in the first radial direction of the wafer, and the plurality of first grooves cover the first surface of the wafer along the first radial direction. The grooving component is used to open a plurality of second grooves perpendicular to the first groove on the first surface of the wafer. The plurality of second grooves are spaced apart in the second radial direction of the wafer, and the plurality of second grooves cover the first surface of the wafer along the second radial direction. The wafer with the first trench and the second trench is subjected to high-temperature annealing; The second surface of a wafer with a first groove and a second groove is polished using a polishing device. The second surface is the side of the wafer opposite to the first surface. The grooving component is a grooving grinding wheel, which includes a plurality of parallel and spaced abrasive rings, each of which is sleeved on the outer circumferential surface of the grooving grinding wheel. The abrasive ring of the slotted grinding wheel is perpendicular to the wafer, and multiple diamond particles are attached to the surface of the abrasive ring, with the size of the diamond particles ranging from 500 to 600.

2. The substrate processing method for reducing deformation stress according to claim 1, characterized in that, The cross-sectional shape of the abrasive ring on the plane passing through the axis of the grooved grinding wheel, as well as the cross-sectional shapes of the first groove and the second groove, are all trapezoidal.

3. The substrate processing method for reducing deformation stress according to claim 2, characterized in that, The top width of the trapezoid is 500±20um, the bottom width is 1000um±20um, the height is 50±20um, and the spacing between two adjacent abrasive rings of the grooved grinding wheel is 2300um±20um.

4. The substrate processing method for reducing deformation stress according to claim 1, characterized in that, A plurality of first trenches parallel to a first direction are formed on the first surface of the wafer using a grooving component, including: The grooving component rotates at a first rotational speed and moves along a first direction to create a plurality of first grooves parallel to the first direction on a first surface of the wafer; and / or The grooving component is used to create a plurality of second trenches perpendicular to the first trenches on the first surface of the wafer, including: The wafer is rotated 90° or 270°, and the grooving component is rotated at a first speed and moved along a first direction to open a plurality of second grooves perpendicular to the first grooves on the first surface of the wafer.

5. The substrate processing method for reducing deformation stress according to claim 4, characterized in that, The first rotational speed range is 2000rpm to 2500rpm, and the grinding time per unit area ranges from 5 to 10 seconds.

6. The substrate processing method for reducing deformation stress according to any one of claims 1 to 5, characterized in that, The abrasive ring is plated with a nickel layer.

7. The substrate processing method for reducing deformation stress according to claim 6, characterized in that, Grinding the wafer includes: The wafer is then subjected to double-sided grinding.

8. A substrate capable of reducing deformation stress, characterized in that, The substrate is fabricated using a substrate processing method that reduces deformation stress as described in any one of claims 1 to 7.

9. The substrate with reduced deformation stress according to claim 8, characterized in that, The number of first trenches on the substrate is 33, and the number of second trenches is 34.

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