Wafer double-side thinning apparatus and method

Abstract

This application discloses a wafer double-sided thinning apparatus and method. The apparatus includes: a first grinding wheel having a first grinding surface arranged horizontally upwards; a second grinding wheel having a second grinding surface arranged horizontally downwards; a planetary plate horizontally disposed between the first and second grinding wheels and having a circular hole; the circular hole is used to place the wafer to be thinned, and the diameter of the circular hole satisfies the same condition as the diameter of the wafer to be thinned; a first support post located below the planetary plate; and a second support post located above the planetary plate; wherein the distance between the axis of the first support post and the axis of the second support post is less than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole; the distance between the rotation axis of the first grinding wheel and the rotation axis of the second grinding wheel is greater than the diameter of the circular hole, and the two rotation axes are symmetrically distributed on both sides of the center of the circular hole.

Description

Technical Field

[0001] This application relates to the field of wafer thinning technology, and more particularly to a wafer double-sided thinning apparatus and method. Background Technology

[0002] With the continuous development of semiconductor manufacturing processes, wafer thickness reduction (such as silicon wafers, silicon carbide wafers, etc.) has become a key process in advanced packaging and power device manufacturing. Wafer thinning requires reducing the wafer thickness to a target thickness while ensuring surface flatness and roughness to meet the requirements of subsequent processes.

[0003] Existing wafer thinning equipment mainly includes two types: single-sided thinning equipment and double-sided thinning equipment. Single-sided thinning equipment involves thinning one side of the wafer first, then flipping the wafer and thinning the other side. Double-sided thinning technology uses two grinding wheels symmetrically positioned on both sides of the carrier, allowing simultaneous grinding of both wafer surfaces. Therefore, double-sided thinning technology has higher thinning efficiency than single-sided thinning technology.

[0004] Existing double-sided thinning devices require a separate drive unit to control the rotation of the planetary plate, enabling the wafer to revolve and rotate within the circular apertures of the planetary plate. When the wafer revolves and rotates within the circular apertures, which are larger than its own diameter, existing double-sided thinning devices lack reliable support for the wafer, making it difficult to ensure stable vertical positioning and clamping of the wafer, thus affecting the processing quality of double-sided wafer thinning. Summary of the Invention

[0005] In view of the above problems, this application provides a wafer double-sided thinning apparatus and method, the specific solution of which is as follows: The first aspect of this application provides a wafer double-sided thinning apparatus, comprising: The first grinding wheel has a first grinding surface that is horizontally upward; The second grinding wheel has a second grinding surface that is horizontally downward. The planetary plate is horizontally positioned between the first grinding wheel and the second grinding wheel, and has a circular hole. The circular hole is used to place the wafer to be thinned, and the diameter of the circular hole and the diameter of the wafer to be thinned meet the same conditions. The first support pillar is located below the planetary plate; The second support column is located above the planetary plate; Among them, the distance between the axis of the first support column and the axis of the second support column is less than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole; the distance between the axis of rotation of the first grinding wheel and the axis of rotation of the second grinding wheel is greater than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole. When performing double-sided thinning on the wafer to be thinned, the first grinding wheel and the second grinding wheel can rotate in opposite directions to grind the upper and lower surfaces of the wafer to be thinned, respectively, and can drive the wafer to be thinned to rotate passively within the circular hole based on the friction between them; the first support column and the second support column abut against the upper and lower surfaces of the wafer to be thinned, respectively, to assist the misaligned first grinding wheel and the second grinding wheel in supporting the wafer to be thinned.

[0006] Optionally, in the above-mentioned wafer double-sided thinning apparatus, the first grinding wheel and the second grinding wheel are respectively connected to independent rotation drive mechanisms; The double-sided thinning device also includes a controller. When performing double-sided thinning on the wafer to be thinned, the controller can control the rotation drive mechanism to drive the first grinding wheel and the second grinding wheel to rotate synchronously at the same speed in opposite directions based on the target thinning thickness of the wafer to be thinned. The controller also drives the first grinding wheel and the second grinding wheel to move towards the wafer to be thinned at a uniform speed to gradually remove the wafer to be thinned.

[0007] Optionally, in the above-mentioned wafer double-sided thinning device, the first support column and the second support column are respectively connected to independent feed drive mechanisms; When performing double-sided thinning on the wafer to be thinned, the controller is also used to control the feed drive mechanism to drive the first support column and the second support column to move towards the wafer to be thinned at a uniform speed based on the target thinning thickness, so that the supporting force of the first support column and the second support column on the wafer to be thinned matches the thinning moving speed of the first grinding wheel and the second grinding wheel, and maintains the horizontal state of the wafer to be thinned.

[0008] Optionally, in the above-mentioned wafer double-sided thinning apparatus, before performing double-sided thinning on the wafer to be thinned, the controller pre-sets the endpoint position when the first support column and the second support column move towards each other based on the target thinning thickness. When performing double-sided thinning on the wafer to be thinned, the controller is also used to stop the double-sided thinning operation when the first support post and the second support post move to the end position, so as to achieve self-limiting of the thinning thickness.

[0009] Optionally, the above-mentioned wafer double-sided thinning apparatus also includes a sensor, which is used to collect detection parameters characterizing the thinning thickness of the wafer to be thinned; When performing double-sided thinning on the wafer, the controller is also used to stop the double-sided thinning operation when the thinning thickness reaches the target thinning thickness based on the detection parameters.

[0010] Optionally, in the above-mentioned wafer double-sided thinning apparatus, the first grinding surface and the second grinding surface have overlapping areas with the circular hole; The distance between the center of the circular hole and the axis of rotation of the first grinding wheel is less than or equal to the radius of the first grinding wheel, and the distance between the center of the circular hole and the axis of rotation of the second grinding wheel is less than or equal to the radius of the second grinding wheel.

[0011] Optionally, in the above-mentioned wafer double-sided thinning device, the ends of the first support column and the second support column used to support the wafer to be thinned are both spherical.

[0012] Optionally, in the above-mentioned wafer double-sided thinning apparatus, the axis of the second support column is located at the center of gravity of the overlapping area of ​​the first grinding surface and the circular hole in the vertical direction. The axis of the first support column is located at the center of gravity of the overlapping area between the second grinding surface and the circular hole in the vertical direction.

[0013] Optionally, the above-mentioned wafer double-sided thinning apparatus further includes: Cooling water supply system; During the double-sided thinning process of the wafer to be thinned, the cooling water supply mechanism is used to continuously spray cooling water onto the upper and lower surfaces of the wafer to be thinned.

[0014] A second aspect of this application provides a method for double-sided wafer thinning, employing any of the aforementioned double-sided wafer thinning apparatus. The method includes: The double-sided thinning device was calibrated. The wafer to be thinned is placed in the circular hole of the planetary plate. The planetary plate limits and centers the wafer to be thinned, and the first support post and the second support post abut against the opposite surface of the wafer to be thinned. Adjust the distance between the first grinding wheel and the second grinding wheel so that the first grinding surface of the first grinding wheel and the second grinding surface of the second grinding wheel abut against the opposite surfaces of the wafer to be thinned. The first and second grinding wheels are controlled to rotate synchronously in opposite directions. During the rotation, the first and second grinding wheels drive the wafer to be thinned to rotate passively within the circular hole based on the friction between the first and second grinding wheels and the wafer to be thinned, so as to perform double-sided thinning of the wafer.

[0015] Optionally, in the above-mentioned double-sided wafer thinning method, the method for calibrating the double-sided thinning apparatus includes: Adjust the coaxiality of the grinding wheel center and its own rotation axis of the first and second grinding wheels, as well as the parallelism of their respective grinding surfaces, so that the support end of the first support column is coplanar with the first grinding surface, and the support end of the second support column is coplanar with the second grinding surface.

[0016] Optionally, the above-mentioned double-sided wafer thinning method further includes: When performing double-sided thinning on the wafer to be thinned, based on the target thinning thickness of the wafer, the first grinding wheel and the second grinding wheel are controlled to rotate synchronously at the same speed in opposite directions, and the first grinding wheel and the second grinding wheel are driven to move towards the wafer to be thinned at a uniform speed to gradually remove the wafer to be thinned.

[0017] Optionally, the above-mentioned double-sided wafer thinning method further includes: When performing double-sided thinning on the wafer to be thinned, based on the target thinning thickness, the first support column and the second support column are controlled to move towards the wafer to be thinned at a uniform speed, so that the supporting force of the first support column and the second support column on the wafer to be thinned matches the thinning moving speed of the first grinding wheel and the second grinding wheel, and maintains the horizontal state of the wafer to be thinned.

[0018] Optionally, the above-mentioned double-sided wafer thinning method further includes: Before performing double-sided thinning on the wafer to be thinned, the endpoint positions of the first support pillar and the second support pillar when they move toward each other are preset based on the target thinning thickness. When performing double-sided thinning on the wafer, the double-sided thinning operation is stopped when the first support post and the second support post move to the end position, so as to achieve self-limiting of the thinning thickness.

[0019] Optionally, the above-mentioned double-sided wafer thinning method further includes: When performing double-sided thinning on a wafer, the detection parameters characterizing the thinning thickness of the wafer are collected in real time. When the target thinning thickness is confirmed based on the detection parameters, the double-sided thinning operation is stopped.

[0020] Optionally, the above-mentioned double-sided wafer thinning method further includes: During the double-sided thinning process of the wafer to be thinned, cooling water is continuously sprayed onto the upper and lower surfaces of the wafer.

[0021] Based on the above description, the technical solution of this application includes at least the following technical effects: First, since the distance between the shafts of the first and second grinding wheels is greater than the diameter of the circular hole, and the two shafts are symmetrically distributed on both sides of the center of the circular hole, when performing double-sided thinning on the wafer to be thinned, the first and second grinding wheels can be staggered and set on the upper and lower sides of the wafer to be thinned, respectively grinding the upper and lower surfaces of the wafer to be thinned. Therefore, when the two grinding wheels rotate in opposite directions, the frictional forces acting on the wafer to be thinned are opposite, and the two opposite frictional forces act on two radii of the same diameter of the wafer to be thinned. The two opposite frictional forces can make the wafer to be thinned passively rotate in the same direction of rotation, so that the two grinding wheels can achieve full synchronous thinning of the upper and lower surfaces of the wafer based on the wafer's rotation.

[0022] Secondly, because the two grinding wheels rotate in opposite directions, the torsional stresses acting on the wafer to be thinned are reversed, eliminating the torsional stress generated by unidirectional grinding. This eliminates the spin-locking and wobbling caused by uneven torsional stress on the upper and lower surfaces of the wafer, allowing the wafer to achieve stable passive spin-rotation within the circular aperture. This reduces edge chipping and fragmentation problems caused by wafer spin-rotation instability. Simultaneously, due to the cancellation of torsional stresses on the upper and lower surfaces of the wafer, the planetary plate only serves to limit the spin-rotation of the wafer edge and does not need to bear the tangential load resisting torsional stress. This reduces mechanical extrusion damage to the wafer edge by the planetary plate and improves the quality of double-sided wafer thinning.

[0023] Third, since the diameter of the circular hole of the planetary plate and the diameter of the wafer to be thinned meet the same conditions, there is no space for the wafer to revolve in the circular hole. Therefore, the friction force of the grinding wheel on the wafer to be thinned can only drive the wafer to be thinned to passively rotate within the circular hole. There is no need for a drive device to control the planetary plate to rotate in order to drive the wafer to revolve, which can simplify the structure of the double-sided wafer thinning device.

[0024] Fourth, since the distance between the axes of the first and second support pillars is less than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole, the two support pillars can be staggered and positioned on the upper and lower sides of the wafer to be thinned. In this way, the staggered support pillars, together with the staggered grinding wheels, can support the wafer to be thinned, providing reliable support and ensuring stable vertical positioning and clamping, thus improving the processing quality of double-sided wafer thinning.

[0025] As can be seen, in the technical solution of this application, the coordinated design of the two staggered grinding wheels and their opposite rotations allows the frictional force exerted by the two grinding wheels on the wafer to be thinned to drive the wafer to rotate stably and passively within a circular aperture of a specific diameter within the plane dimension of the planetary plate. In the vertical dimension, it also provides stable positioning and clamping for the wafer to be thinned. Therefore, the technical solution of this application can improve the processing quality of double-sided wafer thinning. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0027] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0028] Figure 1 This is a schematic diagram of the structure of a wafer double-sided thinning device provided in an embodiment of this application; Figure 2 for Figure 1 Top view of the wafer double-sided thinning apparatus shown; Figure 3 This is a schematic diagram of another wafer double-sided thinning apparatus provided in an embodiment of this application; Figure 4 A schematic diagram of the structure of another wafer double-sided thinning device provided in the embodiments of this application; Figure 5 A top view showing the layout of the planetary wafer and two grinding wheels in a wafer double-sided thinning apparatus provided in this application embodiment; Figure 6 A top view showing the layout of the planetary wafer and two grinding wheels in another wafer double-sided thinning apparatus provided in this application embodiment; Figure 7 A schematic diagram of the structure of another wafer double-sided thinning device provided in the embodiments of this application; Figure 8 This is a schematic flowchart of a wafer double-sided thinning method provided in an embodiment of this application.

[0029] The annotations in the attached figures are explained as follows: First grinding wheel 101, second grinding wheel 102, planetary plate 103, circular hole 104, wafer to be thinned 105, first support column 106, second support column 107, rotation drive mechanism 108, controller 109, feed drive mechanism 110, cooling water supply mechanism 111. Detailed Implementation

[0030] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0031] In conventional double-sided wafer thinning apparatuses, the diameter of the circular aperture of the planetary wafer is larger than the diameter of the wafer. A separate drive device is required to control the rotation of the planetary wafer. Two synchronously rotating grinding wheels are symmetrically positioned on the upper and lower surfaces of the wafer to allow the wafer to rotate and revolve during the double-sided thinning process. During the double-sided thinning operation, the two opposing grinding wheels always perform eccentric grinding on localized areas of the upper and lower surfaces of the wafer (i.e., the center of the grinding wheel does not coincide with the center of the wafer). Based on the wafer's rotation and revolution within the circular aperture of the planetary wafer, full-area grinding of the upper and lower surfaces of the wafer is achieved.

[0032] Based on the above description, conventional wafer double-sided thinning devices mainly use two symmetrically arranged grinding wheels to support the wafer within the circular hole. Since the center of the grinding wheel does not coincide with the center of the wafer, the two opposing grinding wheels can only support a part of the wafer during the double-sided thinning process. There are always some areas of the wafer that cannot be reliably supported. When the upper and lower grinding wheels contact the wafer at the same time and perform grinding, the wafer itself is relatively thin and is prone to bending deformation under the grinding force, resulting in flatness deviation of the thinned wafer and affecting the processing quality.

[0033] In conventional double-sided wafer thinning equipment, if edge clamping or vacuum adsorption is used to position and clamp the wafer in the vertical direction, edge clamping will block the edge area of ​​the wafer, and vacuum adsorption will occupy the processing area on the wafer surface. It is difficult to simultaneously achieve both vertical positioning and clamping of the wafer and comprehensive grinding of the upper and lower surfaces of the wafer without dead angles.

[0034] Furthermore, conventional double-sided wafer thinning devices suffer from poor coordination between the rotation of the upper and lower grinding wheels and the wafer. The independent rotation control of the planetary plate and the grinding wheel leads to poor compatibility between their rotations, resulting in unstable contact between the grinding wheel and the wafer. This makes the wafer prone to breakage, causes the grinding force to shift, and results in rotational jamming, leading to messy grinding marks, localized over-grinding or under-grinding. This fails to meet the high-precision, low-damage, and high-consistency thinning requirements of high-end wafers.

[0035] Therefore, there is an urgent need in the field of wafer thinning technology for a wafer double-sided thinning device with optimized structure, stable support, and high processing precision.

[0036] In view of this, embodiments of this application provide a wafer double-sided thinning apparatus, comprising: The first grinding wheel has a first grinding surface that is horizontally upward; The second grinding wheel has a second grinding surface that is horizontally downward. The planetary plate is horizontally positioned between the first grinding wheel and the second grinding wheel, and has a circular hole. The circular hole is used to place the wafer to be thinned, and the diameter of the circular hole and the wafer to be thinned meet the same condition. The first support pillar is located below the planetary plate; The second support column is located above the planetary plate; Among them, the distance between the axis of the first support column and the axis of the second support column is less than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole; the distance between the axis of rotation of the first grinding wheel and the axis of rotation of the second grinding wheel is greater than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole. When performing double-sided thinning on the wafer to be thinned, the first grinding wheel and the second grinding wheel can rotate in opposite directions to grind the upper and lower surfaces of the wafer to be thinned, respectively, and can drive the wafer to be thinned to rotate passively within the circular hole based on the friction between them; the first support column and the second support column abut against the upper and lower surfaces of the wafer to be thinned, respectively, to assist the misaligned first grinding wheel and the second grinding wheel in supporting the wafer to be thinned.

[0037] In the wafer double-sided thinning apparatus provided in this application, the coordinated design of the two staggered grinding wheels and their opposite rotations allows the frictional force exerted by the two grinding wheels on the wafer to be thinned to drive the wafer to perform stable passive rotation within a circular aperture of a specific diameter within the plane dimension of the planetary plate. Furthermore, in the vertical direction, it also provides stable positioning and clamping for the wafer. Therefore, the technical solution of this application can improve the processing quality of wafer double-sided thinning.

[0038] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments described in this application are merely some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The terminology used in the embodiments of this application is only used to explain the specific embodiments of this application and is not intended to limit this application.

[0039] refer to Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a wafer double-sided thinning device provided in an embodiment of this application. Figure 2 for Figure 1 The diagram shows a top view of the double-sided wafer thinning apparatus. The relative positions of the structural components within the apparatus are illustrated in the top view to clearly show their positions. Figure 2 The two grinding wheels and two support columns are not shown in the image. Figure 2 The relative position of the grinding wheel is indicated by the axis of rotation corresponding to the grinding wheel, and the relative position of the support column is indicated by the axis of rotation corresponding to the support column.

[0040] like Figure 1 and Figure 2 As shown, the wafer double-sided thinning apparatus includes: a first grinding wheel 101, the first grinding wheel 101 having a first grinding surface arranged horizontally upwards. Figure 1 The upper surface of the first grinding wheel 101 is the first grinding surface; the second grinding wheel 102 has a second grinding surface that is horizontally downward. Figure 1 The lower surface of the second grinding wheel 102 is the second grinding surface; the planetary plate 103 is horizontally disposed between the first grinding wheel 101 and the second grinding wheel 102, and has a circular hole 104; the circular hole 104 is used to place the wafer 105 to be thinned, and the diameter of the circular hole 104 and the wafer 105 to be thinned meet the same condition; the first support post 106 is located below the planetary plate 103; the second support post 107 is located above the planetary plate 103.

[0041] The diameter D1 of the circular hole 104 and the diameter D2 of the wafer 105 to be thinned meet the same condition, that is, D1 and D2 are the same, or D1 is slightly larger than D2, so that the wafer 105 to be thinned can be placed in the circular hole 104. Figure 2 In the diagram, O1 represents the center of the circular hole 104, and O2 represents the center of the wafer 105 to be thinned. When the wafer 105 to be thinned is placed in the circular hole 104, O1 and O2 coincide or nearly coincide.

[0042] The first grinding wheel 101 and the second grinding wheel 102 may have the same or different shapes and dimensions. To facilitate the fabrication, installation, and maintenance of the device components, it is preferable that the two grinding wheels have the same shape and dimensions. Each of the two grinding wheels can rotate based on its own axis. Figure 1 and Figure 2 In the diagram, A1 represents the axis of rotation of the first grinding wheel, and A2 represents the axis of rotation of the second grinding wheel.

[0043] The first support column 106 and the second support column 107 may have the same or different shapes and dimensions. The upper end of the first support column 106 is used to support the wafer 105 to be thinned, and the lower end of the second support column 107 is used to support the wafer 105 to be thinned. To facilitate the fabrication of the device components and the installation and maintenance of the device components, it is preferable that the two support columns have the same shape and dimensions. The support column can be a cylinder or a polygonal prism. The line connecting the centerlines of the upper and lower end faces of the support column is its axis. Figure 1 and Figure 2 In the diagram, L1 represents the axis of the first support column 106, and L2 represents the axis of the second support column 107.

[0044] Optionally, the ends of the first support pillar 106 and the second support pillar 107 used to support the wafer 105 to be thinned are both spherical. The spherical ends have self-adaptive bonding capabilities, which can adapt to the slight tilt and warping deformation of the wafer, ensuring reliable bonding between the support pillar and the wafer surface over a large area, avoiding stress concentration at point contacts, and reducing the risk of the wafer being damaged by the support pillar. The material of the two support pillars can be set according to requirements, such as alumina ceramic support pillars.

[0045] In the wafer double-sided thinning apparatus provided in this application embodiment, the distance S2 between the rotation axis A1 of the first grinding wheel 101 and the rotation axis A2 of the second grinding wheel 102 is greater than the diameter D1 of the circular hole 104, and the two rotation axes are symmetrically distributed on both sides of the center of the circular hole 104. Figure 2 As shown, on the plane where the planetary plate 103 is located, the intersection of the axes of rotation of the two grinding wheels with this plane is collinear with the center O2 of the circular hole 104. The intersection of the axes of rotation of the two grinding wheels with this plane is symmetrically located on both sides of the center O2. The distance S1 between the axis L1 of the first support column 106 and the axis L2 of the second support column 107 is less than the diameter D1 of the circular hole 104, and the two axes are symmetrically distributed on both sides of the center O1 of the circular hole 104. Figure 2 As shown, on the plane where the planetary plate 103 is located, the intersection of the axes of the two support columns with the plane is collinear with the center O2 of the circular hole 104, and the intersection of the axes of the two support columns with the plane is symmetrically located on both sides of the center O2.

[0046] like Figure 1 As shown, by selecting a grinding wheel and support column of appropriate size, the first grinding surface of the first grinding wheel 101 can abut against and support the left side of the wafer 105 to be thinned, and the first support column 106 can abut against and support the right side of the wafer 105 to be thinned. Thus, the first support column 106 can work with the first grinding wheel 101 to support the lower surface of the wafer 105 to be thinned, so that the wafer 105 to be thinned can be placed horizontally within the circular hole 104.

[0047] In addition, such as Figure 1 As shown, on the upper surface of the wafer 105 to be thinned, the right side of the wafer 105 can be supported by the second grinding surface of the second grinding wheel 102, and the left side of the wafer 105 can be supported by the second support column 107. Thus, the upper surface of the wafer 105 can be supported by the second support column 107 in conjunction with the second grinding wheel 102. In this way, in the vertical direction, the first grinding wheel 101 and the first support column 106 supporting the lower part of the wafer 105 can stably clamp the wafer 105 to be thinned with the second grinding wheel 102 and the second support column 107 supporting the upper part of the wafer 105, so that it can maintain a horizontal position during the double-sided thinning process, thereby ensuring the quality of double-sided processing.

[0048] In the wafer double-sided thinning apparatus provided in this application embodiment, when performing double-sided thinning on the wafer 105 to be thinned, the first grinding wheel 101 and the second grinding wheel 102 can rotate in opposite directions to grind the upper and lower surfaces of the wafer 105 to be thinned, respectively, and can drive the wafer 105 to be thinned to be passively rotate within the circular hole 104 based on the frictional force between them; the first support column 106 and the second support column 107 respectively abut against the upper and lower surfaces of the wafer 105 to assist the misaligned first grinding wheel 101 and the second grinding wheel 102 in supporting the wafer 105 to be thinned.

[0049] When the wafer double-sided thinning device provided in this application performs double-sided thinning on the wafer 105 to be thinned, the first grinding wheel 101 and the second grinding wheel 102 can be staggered and set on the upper and lower sides of the wafer 105 to be thinned, respectively grinding the upper and lower surfaces of the wafer 105 to be thinned. Therefore, when the two grinding wheels rotate in opposite directions, the frictional forces acting on the wafer 105 to be thinned are opposite, and the two opposite frictional forces act on two radii of the same diameter of the wafer to be thinned. The two opposite frictional forces can make the wafer to be thinned passively rotate in the same rotation direction, so that the two grinding wheels can achieve full synchronous thinning of the upper and lower surfaces of the wafer based on the rotation of the wafer.

[0050] In the wafer double-sided thinning apparatus provided in this application embodiment, since the two grinding wheels rotate in opposite directions, the torsional stresses acting on the wafer to be thinned by the two grinding wheels are reversed, eliminating the torsional stress generated by unidirectional grinding. This can eliminate the spin-locking and wobbling caused by uneven torsional stress on the upper and lower surfaces of the wafer, allowing the wafer 105 to achieve stable passive spin-rotation within the circular hole 104, reducing edge chipping and fragmentation problems caused by wafer spin-rotation instability. At the same time, due to the cancellation of torsional stresses on the upper and lower surfaces of the wafer, the planetary plate 103 only serves to limit the spin-rotation of the wafer edge and does not need to bear the tangential load of resisting torsional stress, reducing the mechanical extrusion damage to the wafer edge by the planetary plate 103 and improving the quality of wafer double-sided thinning.

[0051] Furthermore, since the diameter D1 of the circular hole 104 of the planetary plate 103 and the diameter D2 of the wafer 105 to be thinned meet the same conditions, there is no space for the wafer 105 to revolve in the circular hole 104. Therefore, the friction force of the grinding wheel on the wafer 105 to be thinned can only drive the wafer 105 to passively rotate within the circular hole 104. There is no need for a drive device to control the planetary plate 103 to rotate in order to drive the wafer 105 to revolve. This simplifies the structure of the double-sided wafer thinning device and reduces the cost of the device.

[0052] Furthermore, since the distance S1 between the axis L1 of the first support post 106 and the axis L2 of the second support post 107 is smaller than the diameter D1 of the circular hole 104, and the two axes are symmetrically distributed on both sides of the center O1 of the circular hole 104, the two support posts can be staggered and positioned on the upper and lower sides of the wafer 105 to be thinned. In this way, the staggered two support posts, together with the staggered two grinding wheels, can support the wafer 105 to be thinned, providing reliable support and ensuring stable vertical positioning and clamping, thereby improving the processing quality of double-sided wafer thinning.

[0053] As described above, the staggered arrangement of the two grinding wheels and their counter-rotation in the embodiments of this application, within the plane dimension of the planetary plate 103, allows the frictional force exerted by the two grinding wheels on the wafer 105 to be thinned to drive the wafer 105 to undergo stable passive rotation within the circular hole 104 of a specific diameter; in the vertical dimension, it also provides stable positioning and clamping for the wafer 105 to be thinned. Therefore, the technical solution of this application can improve the processing quality of double-sided wafer thinning.

[0054] It should be noted that the thickness of the planetary plate 103 can be less than the thickness of the wafer 105 after thinning, so that the support pillars and grinding wheels on the same side of the wafer can be coplanar and horizontally abut against the surface of that side during the entire double-sided thinning process, thus avoiding interference of the planetary plate 103 with the grinding quality of the wafer surface.

[0055] like Figure 1 As shown, the axis L2 of the second support column 107 is located at the center of gravity of the overlapping area of ​​the first grinding surface and the circular hole 104 in the vertical direction; the axis L1 of the first support column 106 is located at the center of gravity of the overlapping area of ​​the second grinding surface and the circular hole 104 in the vertical direction. Thus, in the vertical direction, when the overlapping area between the grinding surface of the grinding wheel and the wafer is fixed, the equivalent point of application of the supporting force exerted by the grinding wheel on the overlapping area is located at the center of gravity of the overlapping area. The support column on the opposite side of the overlapping area can abut against this center of gravity, providing a reverse force to the overlapping area. This allows the opposing support columns and the grinding wheel to provide two opposing forces with the same point of application at the center of gravity of the overlapping area, thereby better positioning in the vertical direction to clamp the wafer 105 to be thinned, maintaining the wafer 105 in a horizontal state during double-sided thinning and preventing wafer warping from affecting its surface grinding quality.

[0056] refer to Figure 3 , Figure 3 This is a schematic diagram of another wafer double-sided thinning apparatus provided in an embodiment of this application. Based on other implementations, Figure 3In the wafer double-sided thinning apparatus shown, the first grinding wheel 101 and the second grinding wheel 102 are respectively connected to independent rotation drive mechanisms 108. The double-sided thinning apparatus also includes a controller 109. When performing double-sided thinning on the wafer 105 to be thinned, the controller 109 can control the rotation drive mechanism 108 to drive the first grinding wheel 101 and the second grinding wheel 102 to rotate synchronously in opposite directions at the same speed, based on the target thinning thickness of the wafer 105 to be thinned. The controller 109 can also drive the first grinding wheel 101 and the second grinding wheel 102 to move towards the wafer 105 at a uniform speed, gradually removing the wafer 105 to be thinned. For a given target thinning thickness, the controller 109 can simultaneously control the two grinding wheels to grind half of the target thinning thickness on the upper and lower surfaces of the wafer 105 to be thinned.

[0057] The target thinning thickness is the thickness that needs to be removed by grinding from the wafer 105 to be thinned.

[0058] Optionally, the rotation drive mechanism 108 can be a servo spindle motor or other multi-axis drive device.

[0059] The initial thickness of the wafer 105 to be thinned is a fixed value, and its target thinning thickness is related to the final required processing thickness of the wafer, which is also a fixed value. Figure 3 In the illustrated configuration, the grinding wheels are equipped with independent rotation drive mechanisms 108, which can precisely control the grinding wheel speed and rotation direction through the controller 109 to achieve synchronous rotation of the two grinding wheels in opposite directions at the same speed. The controller 109 can uniformly manage the rotation and feed motion of the grinding wheels to achieve automated control of the grinding process, ensuring a balanced grinding removal rate on both sides of the wafer and avoiding over-grinding or under-grinding on one side.

[0060] refer to Figure 4 , Figure 4 This is a schematic diagram of another wafer double-sided thinning apparatus provided in the embodiments of this application. Figure 3 Based on the method shown, Figure 4 In the wafer double-sided thinning apparatus shown, the first support column 106 and the second support column 107 are respectively connected to independent feed drive mechanisms 110. During double-sided thinning of the wafer 105, the controller 109 is also used to control the feed drive mechanism 110 to drive the first support column 106 and the second support column 107 to move towards the wafer 105 at a uniform speed, based on the target thinning thickness. This ensures that the supporting force of the first support column 106 and the second support column 107 on the wafer 105 matches the thinning movement speed of the first grinding wheel 101 and the second grinding wheel 102, maintaining the horizontal state of the wafer 105. Optionally, the feed drive mechanism 110 can be a servo motor with a linear motor slide.

[0061] exist Figure 4In the illustrated configuration, the support column has an independent feed drive and can move synchronously with the grinding wheel feed. As the wafer thickness decreases, the support column continuously follows and compensates for the displacement, always maintaining bidirectional contact support on the upper and lower surfaces of the wafer, preventing the wafer from losing support and warping during the thinning process, and ensuring the wafer flatness.

[0062] In one embodiment of this application, before performing double-sided thinning on the wafer 105 to be thinned, the controller 109 pre-sets the endpoint positions of the first support column 106 and the second support column 107 when they move toward each other based on the target thinning thickness; when performing double-sided thinning on the wafer 105 to be thinned, the controller 109 is also used to stop the double-sided thinning operation when the first support column 106 and the second support column 107 move to the endpoint positions, so as to achieve self-limiting of the thinning thickness.

[0063] In this method, the controller 109 can determine the endpoint positions of the two support columns in advance based on the initial thickness and target thinning thickness of the wafer 105 to be thinned. When the support columns reach the endpoint positions, the controller controls the rotation drive mechanism 108 and the feed drive mechanism 110 to stop working, thereby stopping the double-sided thinning operation. This method can achieve automatic limiting of wafer thinning thickness, and can accurately control the final thickness without additional thickness measurement feedback. This method relies on the endpoint of the mechanical displacement of the support columns to achieve hardware-level self-limiting of thinning thickness, and does not simply rely on grinding time or grinding wheel feed for control. It can accurately control the final thinning thickness without additional thickness measurement feedback, and can effectively prevent over-grinding.

[0064] In one embodiment of this application, the double-sided thinning device may further include a sensor. The sensor is used to collect detection parameters characterizing the thinning thickness of the wafer 105 to be thinned. During double-sided thinning of the wafer, the controller 109 is also used to stop the double-sided thinning operation when the thinning thickness is confirmed to have reached the target thinning thickness based on the detection parameters. The sensor may be an optical sensor. This method achieves closed-loop feedback control by real-time thickness monitoring using a sensor, further improving the accuracy and reliability of thickness control.

[0065] In the double-sided thinning device, the self-limiting control of the thinning thickness can be achieved solely based on the end position of the support column, or the closed-loop feedback control of the thinning thickness can be achieved solely through the detection parameters of the sensor, or both control schemes can be used simultaneously.

[0066] refer to Figure 5 , Figure 5This is a top view of the layout of a planetary wafer and two grinding wheels in a wafer double-sided thinning apparatus provided in an embodiment of this application. In this configuration, the first grinding surface of the first grinding wheel 101 and the second grinding surface of the second grinding wheel 102 overlap with the circular hole 104. The distance O1A1 between the center O1 of the circular hole 104 and the rotation axis A1 of the first grinding wheel 101 is equal to the radius r1 of the first grinding wheel 101, and the distance O1A2 between the center O1 of the circular hole 104 and the rotation axis A2 of the second grinding wheel 102 is equal to the radius r2 of the second grinding wheel 102.

[0067] refer to Figure 6 , Figure 6 This is a top view of the layout of the planetary wafer and two grinding wheels in another wafer double-sided thinning apparatus provided in this application embodiment. In this configuration, the first grinding surface of the first grinding wheel 101 and the second grinding surface of the second grinding wheel 102 overlap with the circular hole 104. The distance O1A1 between the center O1 of the circular hole 104 and the rotation axis A1 of the first grinding wheel 101 is less than the radius r1 of the first grinding wheel 101, and the distance O1A2 between the center O1 of the circular hole 104 and the rotation axis A2 of the second grinding wheel 102 is less than the radius r2 of the second grinding wheel 102.

[0068] exist Figure 5 and Figure 6 In the method shown, the radial dimension of the area covered by the corresponding grinding wheel on the upper and lower surfaces of the wafer is not less than the wafer radius. Therefore, during the double-sided thinning process, the passive rotation of the wafer can complete the full thinning of the upper and lower surfaces of the wafer, avoiding the occurrence of thinning blind spots on the upper and lower surfaces of the wafer.

[0069] refer to Figure 7 , Figure 7 This is a schematic diagram of another wafer double-sided thinning apparatus provided in the embodiments of this application. Based on other implementation methods, Figure 7 The wafer double-sided thinning apparatus shown also includes a cooling water supply mechanism 111. During the double-sided thinning process of the wafer 105 to be thinned, the cooling water supply mechanism 111 continuously sprays cooling water onto the upper and lower surfaces of the wafer 105. In this method, the continuous spraying of cooling water by the cooling water supply mechanism 111 during the double-sided thinning process can effectively reduce the temperature of the grinding zone, reduce thermal damage and microcracks, and promptly remove grinding debris, ensuring the surface grinding quality.

[0070] Based on the above description, in the wafer double-sided thinning device provided in this application embodiment, two grinding wheels staggered on the upper and lower sides of the planetary wafer are respectively provided with a support column. During the double-sided thinning process of the wafer 105 to be thinned, each grinding wheel can provide a reverse force through the support column. The support column can counteract the bending moment acting on the surface of the wafer 105 to be thinned when the grinding wheels rotate, significantly suppressing the elastic deformation and warping of the wafer 105 to be thinned during the processing, so that the wafer can obtain stable, continuous, uniform and reliable support on both sides. It can effectively suppress wafer bending deformation, improve the flatness (TTV) and thickness consistency of the wafer after thinning, and meet the precision requirements of ultra-thin wafer processing.

[0071] In addition, the double-sided wafer thinning device can achieve passive drive rotation of the wafer 105 to be thinned. Based on two staggered and oppositely rotating grinding wheels, it can provide reverse friction force to two radii of the same diameter of the wafer 105 to be thinned, so that the wafer 105 to be thinned can passively rotate. There is no need for an independent wafer rotation drive mechanism, which simplifies the equipment structure and optimizes the grinding kinematics. Compared to conventional vertical wafer positioning solutions such as edge clamping or vacuum adsorption, in this embodiment, the two staggered support columns can be vertically opposed to the two staggered grinding wheels, providing sufficient holding force for the wafer 105 to be thinned. This allows the wafer 105 to be stably positioned without a dedicated clamping mechanism. The support columns and the opposing grinding wheels can provide reverse support forces to the wafer 105, creating sufficient friction between the grinding wheels and the wafer 105, thereby causing the wafer 105 to passively rotate. The planetary plate 103 and the wafer 105 do not need to be configured with independent rotation drive mechanisms, thus avoiding obstruction and contamination of the upper and lower surfaces of the wafer and simplifying the device structure.

[0072] Furthermore, the double-sided wafer thinning device can also achieve thickness self-limiting control. As described above, the endpoint positions of the two support pillars can be predetermined based on the target thinning thickness. When the wafer 105 to be thinned is thinned to the target thickness that matches the endpoint positions of the two support pillars, the two support pillars no longer move, thus limiting the wafer 105 to be thinned to the predetermined thickness.

[0073] Furthermore, the double-sided wafer thinning device can also improve thinning efficiency and surface quality. Since the upper and lower grinding wheels can rotate synchronously in opposite directions, they grind the upper and lower surfaces of the wafer simultaneously, eliminating the stress asymmetry problem of single-sided grinding. Simultaneously, the passive rotation of the wafer 105 to be thinned achieves a more uniform grinding trajectory, improving surface roughness and processing efficiency. The rotational speed of the wafer 105 is determined by the difference in surface linear velocity between the two grinding wheels and can be flexibly adjusted according to process requirements. The coordinated movement of the wafer 105 and the two grinding wheels ensures that every point on the wafer surface experiences multi-directional, intersecting grinding trajectories, eliminating scratch orientation caused by unidirectional grinding. Simultaneously, the synchronous grinding on both sides balances the grinding forces, resulting in lower surface roughness (Ra) and higher processing efficiency.

[0074] Based on the double-sided thinning apparatus provided in the above embodiments, another embodiment of this application also provides a wafer double-sided thinning method using the above-described double-sided thinning apparatus, which can be performed as follows: Figure 8 As shown.

[0075] refer to Figure 8 , Figure 8 This is a flowchart illustrating a wafer double-sided thinning method provided in an embodiment of this application. The wafer double-sided thinning method includes: Step S11: Perform equipment calibration on the double-sided thinning device.

[0076] In step S11, the method for calibrating the double-sided thinning device includes: adjusting the coaxiality of the centers of the first grinding wheel 101 and the second grinding wheel 102 with their own rotation axes, and the parallelism of their respective grinding surfaces, so that the support end of the first support column 106 is coplanar with the first grinding surface, and the support end of the second support column 107 is coplanar with the second grinding surface. By adjusting the coaxiality of the grinding wheel centers with their own rotation axes, the centers of the two grinding wheels can be made to coincide with their own rotation axes. By adjusting the parallelism of the grinding surfaces of the grinding wheels, the grinding surfaces of the grinding wheels can be made to be parallel to the horizontal plane, thereby ensuring that the rotation axes of the two grinding wheels are parallel to the vertical direction and coincide with the centers of the grinding wheels themselves, so as to prevent the grinding wheel rotation axis from shifting and affecting the grinding quality.

[0077] Step S12: Place the wafer 105 to be thinned into the circular hole 104 of the planetary plate 103. The planetary plate 103 limits and centers the wafer 105 to be thinned, and makes the first support post 106 and the second support post 107 respectively abut against the opposite surface of the wafer 105 to be thinned.

[0078] In step S12, the wafer to be thinned 105 can be centered and positioned by the circular hole 104 of the planetary plate 103, and the wafer to be thinned 105 can be bidirectionally and stably supported by the support pillars on the upper and lower sides of the wafer and the grinding wheel, so as to provide a stable and reliable working posture for subsequent double-sided thinning of the wafer.

[0079] Step S13: Adjust the distance between the first grinding wheel 101 and the second grinding wheel 102 so that the first grinding surface of the first grinding wheel 101 and the second grinding surface of the second grinding wheel 102 respectively abut against the opposite surfaces of the wafer 105 to be thinned.

[0080] In step S13, the distance between the two grinding wheels can be finely adjusted according to the initial thickness and target thinning thickness of the wafer 105 to be thinned, so that the grinding surfaces of the two grinding wheels slightly abut against the upper and lower surfaces of the wafer 105 to be thinned. During this adjustment process, the wafer 105 to be thinned is supported by two support pillars on the upper and lower sides of the wafer 105.

[0081] Step S14: Control the first grinding wheel 101 and the second grinding wheel 102 to rotate synchronously in opposite directions. During the rotation, the first grinding wheel 101 and the second grinding wheel 102 drive the wafer 105 to be thinned to rotate passively within the circular hole 104 based on the friction between them, so as to perform double-sided thinning of the wafer 105.

[0082] In step S14, the rotation drive device is started to control the two grinding wheels to rotate synchronously in opposite directions. During the rotation of the grinding wheels, the friction force can drive the wafer 105 to be thinned to rotate passively, so as to achieve uniform and synchronous thinning of the upper and lower surfaces of the wafer.

[0083] Optionally, the double-sided wafer thinning method further includes: continuously spraying cooling water onto the upper and lower surfaces of the wafer 105 to be thinned during the double-sided thinning process.

[0084] Optionally, the wafer double-sided thinning method further includes: when performing double-sided thinning on the wafer to be thinned, based on the target thinning thickness of the wafer 105 to be thinned, controlling the first grinding wheel 101 and the second grinding wheel 102 to rotate synchronously at the same speed in opposite directions, and driving the first grinding wheel 101 and the second grinding wheel 102 to move towards the wafer 105 to be thinned at a uniform speed, so as to gradually remove the wafer 105 to be thinned.

[0085] Optionally, the wafer double-sided thinning method further includes: when performing double-sided thinning on the wafer to be thinned, based on the target thinning thickness, controlling the first support column 106 and the second support column 107 to move towards the wafer to be thinned 105 at a uniform speed, so that the supporting force of the first support column 106 and the second support column 107 on the wafer to be thinned 105 matches the thinning moving speed of the first grinding wheel 101 and the second grinding wheel 102, and maintaining the horizontal state of the wafer to be thinned 105.

[0086] Optionally, the wafer double-sided thinning method further includes: before performing double-sided thinning on the wafer 105 to be thinned, based on the target thinning thickness, pre-setting the endpoint position when the first support post 106 and the second support post 107 move toward each other; When performing double-sided thinning on the wafer to be thinned, the double-sided thinning operation is stopped when the first support post 106 and the second support post 107 move to the end position, so as to achieve self-limiting of the thinning thickness.

[0087] Optionally, the wafer double-sided thinning method further includes: during the double-sided thinning of the wafer to be thinned, acquiring detection parameters in real time that characterize the thinning thickness of the wafer 105 to be thinned; and stopping the double-sided thinning operation when the thinning thickness is confirmed to have reached the target thinning thickness based on the detection parameters.

[0088] The wafer double-sided thinning method and wafer double-sided thinning apparatus disclosed in the above embodiments have the same or corresponding beneficial effects, and will not be repeated here to avoid repetition.

[0089] The technical effects of the proposed solution will be further explained below, based on comparative experimental data.

[0090] The control group was set up as follows: Using 8-inch silicon carbide epitaxial wafers with an initial thickness of 450 μm and a target thinning thickness of 200 μm, resulting in a final target thickness of 250 μm, 25 wafers were divided into two groups of five. A double-spindle, double-sided thinning machine without support pillars was used. A planetary plate was placed in the middle to hold the wafers, and alumina ceramic material was selected as the support pillars. After placing the wafers, the upper and lower support pillars were lowered and attached to the wafer surface. The processing parameters were: diamond grinding wheel grit #20000, corresponding to an upper and lower spindle speed of 2800 r / min, removing 100 μm from both the carbon and silicon surfaces simultaneously, continuous pure water spraying during processing, and a single continuous processing time of 35 min.

[0091] The experimental group was set up as follows: Using 8-inch silicon carbide epitaxial wafers with an initial thickness of 450 μm and a target thinning thickness of 200 μm, resulting in a post-thinning target thickness of 250 μm, 25 wafers were divided into two groups of five. The wafer double-sided thinning device provided in this embodiment was used. This device features upper and lower dual spindles controlling the rotation of the grinding wheel, with a planetary plate in the middle to hold the wafer. Alumina ceramic material was selected as the support pillars. After placing the wafer, the upper and lower support pillars were lowered to fit against the wafer surface. The processing parameters were: diamond grinding wheel grit #20000, upper and lower spindle speed 2800 r / min, simultaneous removal of 100 μm from both the carbon and silicon surfaces, continuous pure water spraying during processing, and a single continuous processing time of 35 min.

[0092] Table 1 Comparison of grinding wheel speed and number of chips / fractures

[0093] Table 2 Comparison of test data for samples after processing

[0094] Based on the data comparison in Table 1, it can be seen that the technical solution of this application has a lower number of wafer cracks / edge chips. Based on the data comparison in Table 2, it can be seen that the wafer thinning quality grade in this application is all qualified Grade A or Grade B, and there is no lowest grade C or unqualified grade NG.

[0095] The various embodiments in this application are described in a progressive, parallel, or combined manner. Each embodiment focuses on its differences from other embodiments, and similar or identical parts between embodiments can be referred to interchangeably. The embodiments provided in this application can be combined with each other without contradiction.

[0096] It should be noted that, in the description of this application, the accompanying drawings and embodiments are illustrative rather than restrictive. The same reference numerals throughout the embodiments identify the same structures. Additionally, for ease of understanding and description, the thicknesses of some layers, films, panels, regions, etc., may be exaggerated in the drawings. It is also understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be intermediate elements. Furthermore, "on" means positioning an element on or below another element, but does not inherently mean positioning it above another element according to the direction of gravity.

[0097] The terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for 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. Therefore, they should not be construed as limitations on this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the middle.

[0098] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0099] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wafer double-side thinning apparatus, characterized by, include: A first grinding wheel, the first grinding wheel having a first grinding surface arranged horizontally upward; The second grinding wheel has a second grinding surface that is horizontally downward. A planetary plate, which is horizontally disposed between the first grinding wheel and the second grinding wheel, and has a circular hole; the circular hole is used to place the wafer to be thinned, and the diameter of the circular hole and the diameter of the wafer to be thinned meet the same condition; A first support column is located below the planetary plate; The second support column is located above the planetary plate; Wherein, the distance between the axis of the first support column and the axis of the second support column is less than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole; the distance between the axis of rotation of the first grinding wheel and the axis of rotation of the second grinding wheel is greater than the diameter of the circular hole, and the two axes are symmetrically distributed on both sides of the center of the circular hole. When performing double-sided thinning on the wafer to be thinned, the first grinding wheel and the second grinding wheel can rotate in opposite directions to grind the upper and lower surfaces of the wafer to be thinned, respectively, and can drive the wafer to be thinned to passively rotate within the circular hole based on the friction between them; the first support column and the second support column abut against the upper and lower surfaces of the wafer to be thinned, respectively, to assist the misaligned first grinding wheel and the second grinding wheel in supporting the wafer to be thinned.

2. The wafer double-sided thinning apparatus according to claim 1, characterized in that, The first grinding wheel and the second grinding wheel are each connected to an independent rotation drive mechanism; The double-sided thinning device also includes a controller. When performing double-sided thinning on the wafer to be thinned, the controller can control the rotation drive mechanism to drive the first grinding wheel and the second grinding wheel to rotate synchronously at the same speed in opposite directions based on the target thinning thickness of the wafer to be thinned, and drive the first grinding wheel and the second grinding wheel to move towards the wafer to be thinned at a uniform speed to gradually remove the wafer to be thinned.

3. The wafer double-sided thinning apparatus according to claim 2, characterized in that, The first support column and the second support column are each connected to an independent feed drive mechanism; When performing double-sided thinning on the wafer to be thinned, the controller is also used to control the feed drive mechanism to drive the first support column and the second support column to move towards the wafer to be thinned at a constant speed based on the target thinning thickness, so that the supporting force of the first support column and the second support column on the wafer to be thinned matches the thinning moving speed of the first grinding wheel and the second grinding wheel, and maintains the horizontal state of the wafer to be thinned.

4. The wafer double-sided thinning apparatus according to claim 3, characterized in that, Before performing double-sided thinning on the wafer to be thinned, the controller pre-sets the endpoint position when the first support column and the second support column move towards each other based on the target thinning thickness. When performing double-sided thinning on the wafer to be thinned, the controller is also used to stop the double-sided thinning operation when the first support post and the second support post move to the end position, so as to achieve self-limiting of the thinning thickness.

5. The wafer double-sided thinning apparatus according to claim 3, characterized in that, It also includes sensors for acquiring detection parameters characterizing the thinning thickness of the wafer to be thinned; When performing double-sided thinning on the wafer to be thinned, the controller is also used to stop the double-sided thinning operation when the thinning thickness is confirmed to have reached the target thinning thickness based on the detection parameters.

6. The wafer double-sided thinning apparatus according to claim 1, characterized in that, The first grinding surface and the second grinding surface each have overlapping areas with the circular hole. The distance between the center of the circular hole and the axis of rotation of the first grinding wheel is less than or equal to the radius of the first grinding wheel, and the distance between the center of the circular hole and the axis of rotation of the second grinding wheel is less than or equal to the radius of the second grinding wheel.

7. The wafer double-sided thinning apparatus according to claim 1, characterized in that, The ends of the first support column and the second support column used to support the wafer to be thinned are both spherical.

8. The wafer double-sided thinning apparatus according to claim 1, characterized in that, The axis of the second support column is located at the center of gravity of the overlapping area of ​​the first grinding surface and the circular hole in the vertical direction; The axis of the first support column is located at the center of gravity of the overlapping area between the second grinding surface and the circular hole in the vertical direction.

9. The wafer double-sided thinning apparatus according to any one of claims 1-8, characterized in that, Also includes: Cooling water supply system; During the double-sided thinning process of the wafer to be thinned, the cooling water supply mechanism is used to continuously spray cooling water onto the upper and lower surfaces of the wafer to be thinned.

10. A method for double-sided thinning of a wafer, characterized in that, The wafer double-sided thinning method, employing the wafer double-sided thinning apparatus as described in any one of claims 1-9, comprises: The double-sided thinning device was calibrated. The wafer to be thinned is placed in the circular hole of the planetary plate. The planetary plate limits and centers the wafer, and the first support post and the second support post abut against the opposite surface of the wafer to be thinned. Adjust the distance between the first grinding wheel and the second grinding wheel so that the first grinding surface of the first grinding wheel and the second grinding surface of the second grinding wheel respectively abut against the opposite surfaces of the wafer to be thinned; The first grinding wheel and the second grinding wheel are controlled to rotate synchronously in opposite directions. During the rotation, the first grinding wheel and the second grinding wheel drive the wafer to be thinned to rotate passively within the circular hole based on the friction between the first grinding wheel and the wafer to be thinned, so as to perform double-sided thinning of the wafer.

11. The wafer double-sided thinning method according to claim 10, characterized in that, The method for calibrating the double-sided thinning device includes: Adjust the coaxiality of the grinding wheel center and its own rotation axis of the first grinding wheel and the parallelism of their respective grinding surfaces, and make the supporting end of the first support column coplanar with the first grinding surface, and the supporting end of the second support column coplanar with the second grinding surface.

12. The wafer double-sided thinning method according to claim 10, characterized in that, Also includes: When performing double-sided thinning on the wafer to be thinned, based on the target thinning thickness of the wafer to be thinned, the first grinding wheel and the second grinding wheel are controlled to rotate synchronously at the same speed in opposite directions, and the first grinding wheel and the second grinding wheel are driven to move towards the wafer to be thinned at a uniform speed to gradually remove the wafer to be thinned.

13. The wafer double-sided thinning method according to claim 12, characterized in that, Also includes: When performing double-sided thinning on the wafer to be thinned, based on the target thinning thickness, the first support column and the second support column are controlled to move towards the wafer to be thinned at a uniform speed, so that the supporting force of the first support column and the second support column on the wafer to be thinned matches the thinning moving speed of the first grinding wheel and the second grinding wheel, and the wafer to be thinned is maintained in a horizontal state.

14. The wafer double-sided thinning method according to claim 10, characterized in that, Also includes: Before performing double-sided thinning on the wafer to be thinned, the endpoint position of the first support column and the second support column when they move toward each other is preset based on the target thinning thickness. When performing double-sided thinning on the wafer to be thinned, the double-sided thinning operation is stopped when the first support post and the second support post move to the endpoint position, so as to achieve self-limiting of the thinning thickness.

15. The wafer double-sided thinning method according to claim 10, characterized in that, Also includes: During the double-sided thinning of the wafer to be thinned, detection parameters characterizing the thinning thickness of the wafer to be thinned are collected in real time. When the thinning thickness is confirmed to have reached the target thinning thickness based on the detection parameters, the double-sided thinning operation is stopped.

16. The wafer double-sided thinning method according to any one of claims 10-15, characterized in that, Also includes: During the double-sided thinning process of the wafer to be thinned, cooling water is continuously sprayed onto the upper and lower surfaces of the wafer.

Images