Wafer thinning apparatus and thinning method

Abstract

The application relates to the technical field of integrated circuit manufacturing, and provides a wafer thinning device and a thinning method, wherein the thinning method comprises the following steps: acquiring a surface shape feature of a wafer in a wafer grinding process of the wafer thinning device, the surface shape feature comprising a concave-convex degree and a fullness degree; decoupling the concave-convex degree and the fullness degree based on an adjustment relationship between an inclination angle and the surface shape feature, and determining a first-dimension compensation angle and a second-dimension compensation angle based on the surface shape feature; and first adjusting the inclination angle of a main shaft in a first dimension based on the first-dimension compensation angle, and then adjusting the inclination angle of the main shaft in a second dimension based on the second-dimension compensation angle. The application effectively improves the grinding precision and grinding efficiency of the wafer.

Description

Technical Field

[0001] This application belongs to the field of integrated circuit manufacturing technology, and more specifically, relates to a wafer thinning device and a thinning method. Background Technology

[0002] Three-dimensional integrated circuits (3D ICs) are an important technological path for the semiconductor industry to continue Moore's Law and improve chip performance and integration. The core idea is to stack multiple chips or functional layers vertically and achieve interlayer electrical connections through interconnection technologies such as through-silicon vias (TSVs), thereby achieving higher functional density within a limited space.

[0003] Wafer thinning is a key supporting process in 3D IC manufacturing, its main purpose being to reduce the wafer's thickness from its original level to an ultra-thin state suitable for vertical integration. Ultra-thin wafers are the physical basis for 3D stacking and are crucial for optimizing electrical performance and thermal management. As the number of 3D IC stacking layers increases, the requirements for the thinning thickness of individual wafers become increasingly stringent. Simultaneously, 3D IC technology places extremely high demands on the surface quality of the thinned wafer, including excellent Total Thickness Variation (TTV) and extremely low Roughness Average (Ra), to ensure the accuracy, consistency, and stability of subsequent bonding processes.

[0004] To achieve the aforementioned thinning targets, wafer thinning equipment typically utilizes the physical grinding action of grinding wheels to process ultra-thin wafers. Such equipment must have its grinding structure and grinding process precisely designed and controlled to meet the requirements for ultra-thin wafer processing (such as thickness ≤10μm, TTV ≤1.5μm, and Ra ≤5nm) while also considering manufacturing costs and production efficiency.

[0005] The spindle's position directly affects the contact angle between the grinding wheel and the wafer. Therefore, adjusting the spindle tilt angle can be used to adjust the wafer's surface features, thereby improving the grinding accuracy. Currently, the industry has proposed a grinding device with a tiltable spindle assembly, which can adjust the spindle angle to change the direction of the grinding force and adjust the grinding surface. This grinding device provides a structure for adjusting the spindle tilt angle, but it does not propose a quantitative adjustment target or a clear adjustment process. Therefore, it can only be adjusted blindly, resulting in low adjustment efficiency and unreliable adjustment accuracy. This leads to the gradual accumulation of wafer surface deviations due to the lack of timely correction, ultimately making it difficult to meet the grinding accuracy requirements and causing a decrease in wafer yield. Summary of the Invention

[0006] Based on the above problems, this application provides a wafer thinning apparatus and a thinning method, which aims to at least solve or alleviate one of the technical problems existing in the prior art.

[0007] A first aspect of this application provides a wafer thinning apparatus, comprising: a grinding device, an adsorption platform, and an adjustment unit;

[0008] The adsorption platform is used to support the wafer and drive its rotation;

[0009] The grinding device is raised and lowered above the adsorption platform. The grinding device includes: a grinding wheel for grinding wafers and a spindle connected to the grinding wheel for driving the grinding wheel to rotate. The ground wafer has surface features, including unevenness and fullness.

[0010] The adjustment unit is used to decouple concavity and fullness based on the adjustment relationship between tilt angle and surface features, and to determine the first-dimensional compensation angle and the second-dimensional compensation angle based on the surface features. First, the tilt angle of the principal axis in the first dimension is adjusted based on the first-dimensional compensation angle, and then the tilt angle of the principal axis in the second dimension is adjusted based on the second-dimensional compensation angle. The adjustment relationship between tilt angle and surface features includes: changes in the tilt angle of the principal axis in the first dimension cause changes in both concavity and fullness, while changes in the tilt angle in the second dimension cause changes in fullness but no change in concavity.

[0011] In one embodiment, the adjustment unit includes: a monitoring module, a decision-making module, and an execution module;

[0012] The monitoring module is used to acquire the surface features of the wafer during the wafer thinning process.

[0013] The decision module is used to call the first model to read the surface features to determine the first dimension compensation angle and the second dimension compensation angle; the first model is an arc surface model constructed based on the grinding line formed when the grinding wheel contacts the wafer, and the arc surface model is used to characterize the correspondence between the surface features and the tilt angle of the principal axis in the first and second dimensions;

[0014] The execution module is used to adjust the tilt angle of the main axis in the first dimension and the tilt angle in the second dimension based on the first dimension compensation angle and the second dimension compensation angle, respectively.

[0015] In one embodiment, the adjustment unit is configured to:

[0016] Determine if the concavity is less than the first threshold. If so, proceed to determine if the fullness is less than the second threshold. Otherwise, call the first model to read the concavity and fullness to determine the first dimension compensation angle.

[0017] The execution module adjusts the spindle tilt angle in the first dimension based on the first dimension compensation angle, and then triggers the monitoring module to continue the acquisition operation after the preset grinding time continues.

[0018] Determine if the fullness is less than the second threshold. If so, trigger the monitoring module to continue the acquisition operation after the preset grinding time. Otherwise, call the first model to read the concavity and fullness to determine the second dimension compensation angle.

[0019] The execution module adjusts the spindle tilt angle in the second dimension based on the second dimension compensation angle, and then triggers the monitoring module to continue the acquisition operation after the preset grinding time continues.

[0020] In one embodiment, the grinding apparatus further includes a spindle seat, a feed mechanism, and an adjusting pad, wherein the spindle is rotatably coaxially disposed within the spindle seat; the spindle seat is connected to the feed mechanism;

[0021] An adjusting shim is at least partially inserted between the feed mechanism and the spindle seat. The grinding device adjusts the insertion depth of the adjusting shim based on a first-dimensional compensation angle to adjust the spindle tilt angle in the first dimension.

[0022] In one embodiment, the regulating pad is provided with a temperature regulating component;

[0023] The adjustment unit is electrically connected to the temperature control component and is used to determine the target temperature based on the first dimension compensation angle and the second model. The execution module adjusts the temperature of the temperature control component to make the temperature of the adjustment pad reach the target temperature, so that the adjustment pad deforms based on the temperature change to adjust the tilt angle of the spindle in the first dimension.

[0024] In one embodiment, the adjusting pad includes an upper pad and a lower pad, which are inserted downward and upward, respectively, between the feed mechanism and the spindle seat, and a temperature regulating component is disposed on at least one of the upper and lower pads.

[0025] In one embodiment, the temperature regulating component includes:

[0026] A temperature sensor and at least one temperature control actuator are included. Both the temperature sensor and the temperature control actuator are electrically connected to the regulating unit. The temperature sensor is used to monitor the temperature of the regulating pad.

[0027] In one embodiment, the contact portion between the grinding wheel and the wafer forms an arc-shaped grinding line, with one end of the grinding line at the center of the wafer and the other end at the edge of the wafer. The first dimension is the wafer radius direction where both ends of the grinding line are located, and the second dimension is a horizontally extending direction perpendicular to the first dimension.

[0028] A second aspect of this application provides a thinning method, comprising the following steps:

[0029] S1: Obtain the surface features of the wafer during the wafer thinning process using a wafer thinning equipment. The surface features include: unevenness and fullness.

[0030] S2: Based on the adjustment relationship between tilt angle and surface features, decouple concavity and fullness to adjust the tilt angle of the principal axis in the first dimension and / or the tilt angle in the second dimension. The adjustment relationship between tilt angle and surface features includes: changes in the tilt angle in the first dimension cause changes in both concavity and fullness, and changes in the tilt angle in the second dimension cause changes in fullness but no change in concavity.

[0031] S2 includes:

[0032] S21: Determine whether the concavity is less than the first threshold. If so, execute S22. Otherwise, call the first model to read the concavity and fullness to determine the first dimension compensation angle, and adjust the spindle tilt angle in the first dimension based on the first dimension compensation angle. Then, after continuing grinding for a preset time, execute step S1.

[0033] S22: Determine whether the fullness is less than the second threshold. If so, continue grinding for a preset time and then execute step S1. Otherwise, call the first model to read the concavity and fullness to determine the second dimension compensation angle, and adjust the spindle tilt angle in the second dimension based on the second dimension compensation angle. Then continue grinding for a preset time and then execute step S1.

[0034] In one embodiment, the first model is an arc surface model based on the grinding lines formed when the grinding wheel contacts the wafer. The arc surface model is used to characterize the correspondence between the surface features and the tilt angles of the principal axis in the first and second dimensions.

[0035] In one embodiment, calling the first model to read the concavity and saturation to determine the first dimension compensation angle includes:

[0036] Call the first model to read the concavity and fullness, and obtain the tilt angle of the current principal axis in the first dimension output by the first model;

[0037] The first dimension compensation angle is determined based on the difference between the current tilt angle of the main axis in the first dimension and the preset target tilt angle in the first dimension;

[0038] Calling the first model to read the concavity and fullness to determine the second dimension compensation angle includes:

[0039] Call the first model to read the concavity and fullness, and obtain the tilt angle of the current principal axis in the second dimension output by the first model;

[0040] The second-dimensional compensation angle is determined based on the difference between the current tilt angle of the main axis in the second dimension and the preset target tilt angle in the second dimension.

[0041] In one embodiment, adjusting the tilt angle of the principal axis in the first dimension based on the first dimension compensation angle includes:

[0042] Input the first dimension compensation angle into the second model to determine the target temperature;

[0043] Adjust the temperature of the adjusting pad to reach the target temperature, so that the adjusting pad deforms accordingly based on the temperature change, thereby adjusting the tilt angle of the spindle in the first dimension.

[0044] In one embodiment, the adjusting shim includes an upper shim and a lower shim that are respectively inserted downwards and upwards between the spindle seat and the feed mechanism, and the second model is constructed as follows:

[0045] Based on the horizontal displacements of the upper and lower pads at the upper and lower supports respectively after thermal deformation, the tilt angle of the principal axis of the upper and lower pads after thermal deformation in the first dimension is calculated. Based on the equality relationship that the difference between the tilt angle of the principal axis of the upper and lower pads after thermal deformation in the first dimension and the initial tilt angle of the principal axis in the first dimension is equal to the compensation angle in the first dimension, the target temperature at which the lower or upper pad undergoes deformation is determined.

[0046] In one embodiment, the thinning method includes:

[0047] When the compensation angle in the first dimension is greater than 0°, the target temperature at which the lower pad deforms is solved using the second model, and the temperature of the lower pad is adjusted to the target temperature.

[0048] When the compensation angle in the first dimension is less than 0°, the target temperature at which the upper pad deforms is calculated using the second model, and the temperature of the upper pad is adjusted to the target temperature.

[0049] In one embodiment, the adjustment precision of the first dimension compensation angle is 0.0001°.

[0050] The beneficial effects of the wafer thinning equipment and thinning method provided in this application embodiment are as follows:

[0051] This application can, after obtaining the surface features of the wafer during the wafer grinding process of the wafer thinning equipment, determine two-dimensional compensation angles based on the surface features and a first model, and decouple concavity and fullness based on the adjustment relationship between the tilt angle and the surface features. First, the tilt angle of the main shaft in the first dimension is adjusted based on the first-dimensional compensation angle, and the change in the tilt angle of the main shaft in the first dimension causes both concavity and fullness to change; second, the tilt angle of the main shaft in the second dimension is adjusted based on the second-dimensional compensation angle, and the change in the tilt angle of the main shaft in the second dimension causes the fullness to change, while the concavity remains unchanged.

[0052] This decoupling adjustment method ensures that the tilt angle adjustment of the spindle in the two dimensions does not affect each other, and the concavity and fullness are no longer coupled. This avoids blind and inefficient adjustment of the tilt angle of the spindle in the two dimensions, which can improve the accuracy and efficiency of the tilt angle adjustment in the two dimensions, thereby effectively improving the accuracy of wafer grinding.

[0053] This application can automatically determine the compensation angle and automatically adjust the spindle tilt angle based on the compensation angle, realizing dynamic adjustment and closed-loop control of wafer surface features, effectively improving the overall efficiency of wafer grinding. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the structure of a wafer thinning apparatus provided in one embodiment of this application;

[0056] Figure 2 A schematic diagram of the surface features of a wafer provided in an embodiment of this application;

[0057] Figure 3 A schematic diagram of the surface features of a wafer provided in another embodiment of this application;

[0058] Figure 4 for Figure 1 Schematic diagram of the intermediate grinding device;

[0059] Figure 5 for Figure 4 Left view of the intermediate grinding unit;

[0060] Figure 6 for Figure 4 Front view of the intermediate grinding unit;

[0061] Figure 7 for Figure 6 A cross-sectional view at position BB in the middle;

[0062] Figure 8 for Figure 6 A magnified view of a portion of position A in the middle;

[0063] Figure 9 This is a flowchart of a thinning method provided in an embodiment of this application;

[0064] Figure 10 This is a schematic diagram of a grinding wheel used for wafer grinding according to an embodiment of this application;

[0065] Figure 11 A flowchart of a thinning method provided in another embodiment of this application;

[0066] Figure 12 This is a structural block diagram of a thinning device provided in one embodiment of this application;

[0067] Figure 13 This is a schematic block diagram of an electronic device provided in an embodiment of this application.

[0068] The attached figures are labeled as follows:

[0069] 10. Grinding device; 11. Grinding wheel; 12. Spindle; 13. Spindle seat; 131. Main body; 132. Wing plate; 1321. Upper threaded hole; 14. Feed mechanism; 141. Slide rail; 142. Slider; 151. Upper pad; 1511. Upper fulcrum; 152. Lower pad; 1521. Horizontal part; 1522. Lower fulcrum; 16. Depth adjustment part; 171. Side plate; 172. Upper adjusting bolt; 173. Lower adjusting bolt; 174. Rotating shaft; 20. Adsorption platform; 30. Worktable; 40. Base; 50. Wafer; 110. Monitoring module; 111. Decision module; 112. Execution module; 600. Electronic equipment; 601. Processor; 602. Input device; 603. Output device; 604. Memory; 605. Communication bus. Detailed Implementation

[0070] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0071] To keep the drawings concise, each drawing only schematically shows the parts relevant to the disclosure; these do not represent the actual structure of the product. Furthermore, for ease of understanding, in some drawings, only one of components with the same structure or function is schematically shown, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one," and "several" includes "two" and "more than two."

[0072] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0073] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0074] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to 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.

[0075] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0076] It should be understood that, unless the context clearly states otherwise, the terms "comprising," "including," or "having" as used herein refer to the presence of an element, but do not exclude the presence or addition of one or more other elements. Furthermore, "comprising" and / or "including" as used herein specify the presence of shapes, numbers, steps, operations, members, elements, and / or combinations thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, elements, and / or combinations thereof. Some embodiments of this application are described in detail below with reference to the accompanying drawings. Where there is no conflict between the embodiments, the following embodiments and features can be combined with each other. The steps in the following method embodiments are for illustrative purposes only and are not intended to limit this application.

[0077] Figure 1 This illustration shows a schematic diagram of a wafer thinning apparatus according to one embodiment of the present application, including a grinding device 10 and a worktable 30. The worktable 30 has an adsorption platform 20, which can hold a wafer 50 by adsorption and rotate the wafer 50. The grinding device 10 is vertically and vertically positioned above the adsorption platform 20. The grinding device 10 includes a spindle 12 and a grinding wheel 11, which are coaxially connected and drive the grinding wheel 11 to rotate. During the rotation of the grinding wheel 11, the wafer 50 can be ground. A semi-contact grinding method can be used, meaning the grinding wheel 11 only contacts the area from the center to the edge of the wafer 50 for grinding. After grinding, the wafer 50 has surface features.

[0078] The surface features of wafer 50 include unevenness and fullness. Figure 2 and Figure 3 Examples of convex and concave surface roughness and fullness are provided for two cases: convex surface roughness and concave surface roughness. δ1 represents convex surface roughness, and δ2 represents fullness. Convex surface roughness δ1 is the height difference between the wafer center and the edge on the wafer surface, i.e., the center height, which reflects the degree of convexity / concavity of wafer 50. Fullness δ2 is the maximum distance between the wafer 50 surface and the lines connecting the wafer 50 center and the edge, reflecting the fullness of the wafer 50 solid.

[0079] like Figure 4 As shown Figure 1 A schematic diagram of the grinding device 10 in the middle. Figure 5 for Figure 4 Left view of the grinding apparatus 10 shown. Figure 6 for Figure 4 Front view of the grinding apparatus 10 shown; see reference Figure 4 , Figure 5 and Figure 6 The grinding apparatus 10 of this embodiment also includes a spindle seat 13, a feed mechanism 14, and an adjusting pad. The spindle 12 is rotatably coaxially disposed in the spindle seat 13, the spindle seat 13 is connected to the feed mechanism 14, and the adjusting pad is at least partially inserted between the feed mechanism 14 and the spindle seat 13.

[0080] In one embodiment, the feed mechanism 14 includes two vertically arranged slide rails 141 and two sliders 142 movably disposed on the slide rails 141 in the vertical direction. The slide rails 141 are fixed to the base 40 of the wafer thinning equipment. The spindle seat 13 includes a tubular main body 131 and outwardly extending wing plates 132 on its left and right sides. The spindle 12 is rotatably coaxially disposed within the main body 131. The wing plates 132 are parallel to the outer sides of the sliders 142, and the two wing plates 132 are respectively connected to the two sliders 142. Therefore, the spindle seat 13 and the spindle 12 as a whole can move vertically along the slide rails 141, thereby driving the grinding wheel 11 to rise and fall.

[0081] In one embodiment, such as Figure 5 As shown, there are two adjusting pads: an upper pad 151 and a lower pad 152. The lower pad 152 can be a wedge-shaped plate. The upper pad 151 and the lower pad 152 are inserted downwards and upwards between the feed mechanism 14 and the spindle seat 13, respectively.

[0082] In one embodiment, an adjustment pad is disposed between the wing plate 132 and the slider 142. The change in the depth of the adjustment pad inserted between the wing plate 132 and the slider 142 will change the distance between the lower positions of the wing plate 132 and the slider 142, thereby changing the tilt angle of the main shaft 12 in the first dimension.

[0083] In one embodiment, such as Figure 7 As shown, the lower pad 152 is a wedge-shaped plate, and its lower end has a horizontal portion 1521 extending below the slider 142. The horizontal portion 1521 is provided with a rotatable depth adjustment portion 16, which is fixed in a vertically relative position to the horizontal portion 1521. The slider 142 has a depth-adjusting threaded hole that mates with the depth adjustment portion 16. Rotation of the depth adjustment portion 16 changes its depth within the depth-adjusting threaded hole, simultaneously moving the lower pad 152 and changing the depth at which it is inserted between the wing plate 132 and the slider 142. The depth adjustment portion 16 can rotate under the drive of components such as an adjustment motor. For example, the adjustment motor can be controlled to rotate according to the first-dimensional compensation angle, thereby achieving automatic adjustment of the tilt angle of the spindle 12 in the first dimension. In this embodiment, the user can set the thickness variation rate of the lower pad 152 along the vertical direction as needed, thereby controlling the adjustment accuracy of the tilt angle of the spindle 12 in the first dimension.

[0084] In another embodiment, a temperature-regulating component is provided in the adjusting pad. The adjusting pad can deform based on temperature changes to adjust the tilt angle of the main shaft 12 in the first dimension. When there are two adjusting pads, the temperature-regulating component is provided in at least one of the upper pad 151 and the lower pad 152. For example, the temperature-regulating component is provided in the lower pad 152, which can control the temperature of the lower pad 152. The lower pad 152 has the property of thermal expansion and contraction. During thermal expansion and contraction, the lower pad 152 changes the distance between the lower position of the wing plate 132 and the slider 142, that is, the lower pad 152 deforms in the horizontal direction, thereby realizing the fine adjustment of the tilt angle of the main shaft 12 in the first dimension. The volume change caused by the deformation of the lower pad 152 due to temperature changes is usually small. This embodiment utilizes the thermal expansion and contraction property of the lower pad 152 to adjust the tilt angle of the main shaft 12 in the first dimension by adjusting the temperature of the lower pad 152, achieving higher adjustment accuracy, which can reach 0.0001°.

[0085] In another embodiment, temperature regulating components are provided on both the upper pad 151 and the lower pad 152. By coordinating the temperature changes of the upper pad 151 or the lower pad 152, the tilt angle of the spindle 12 in the first dimension can be reduced or increased. See also Figure 5As shown, when the thickness of the upper pad 151 changes, the thickness of the upper pad 151 at the upper support point 1511 changes, causing the main shaft seat 13 to rotate in the first dimension, thereby increasing the forward tilt angle of the main shaft 12. When the thickness of the lower pad 152 changes, the thickness of the lower pad 152 at the lower support point 1522 changes, causing the main shaft seat 13 to rotate in the first dimension, thereby increasing the backward tilt angle of the main shaft 12. It should be noted that the upper support point 1511 is the position where the upper end of the upper pad 151 contacts the airfoil 132. When the upper pad 151 is a wedge-shaped plate, the upper support point 1511 is always the position where the thickness of the upper pad 151 is the greatest. The lower support point 1522 is the position where the lower end of the lower pad 152 contacts the airfoil 132. When the lower pad 152 is a wedge-shaped plate, the lower support point 1522 is always the position where the thickness of the lower pad 152 is the greatest. When adjusting the temperature, the vertical positions of the upper support 1511 and the lower support 1522 will not change, and the vertical distance between the upper support 1511 and the lower support 1522 will remain unchanged.

[0086] It should be noted that this application can combine the tilt angle adjustment method using the depth adjustment unit 16 and the tilt angle adjustment method using the temperature control component. The depth adjustment unit 16 adjusts the depth of the adjustment shim inserted between the wing plate 132 and the slider 142 for coarse tilt angle adjustment, while the temperature control component adjusts the temperature of the adjustment shim to adjust the tilt angle by deforming the adjustment shim for fine spindle tilt angle adjustment. Combining coarse and fine adjustment achieves a balance between adjustment efficiency and accuracy.

[0087] In some embodiments, reference Figure 6 and Figure 8 ,in, Figure 8 for Figure 6A partial enlarged view at position A shows that the grinding device 10 also includes an upper adjusting bolt 172, a lower adjusting bolt 173, and a rotating shaft 174. The rotating shaft 174 vertically penetrates the front of the wing plate 132 and inserts into the slider 142, allowing the spindle seat 13, along with the spindle 12, to rotate around the rotating shaft 174 to adjust the tilt angle of the spindle 12 in the second dimension. The upper adjusting bolt 172 and the lower adjusting bolt 173 can adjust the angle of the spindle seat 13. Specifically, a side plate 171 is provided on the side of the wing plate 132 away from the main body 131, and the side plate 171 is fixedly connected to the slider 142. The side plate 171 has an upper through hole and a lower through hole that penetrate along the second dimension and are distributed vertically. The upper adjusting bolt 172 and the lower adjusting bolt 173 are rotatably disposed in the upper through hole and the lower through hole, respectively. The wing plate 132 has an upper threaded hole 1321 and a lower threaded hole on its side facing the side plate 171, corresponding to the positions of the upper and lower through holes, respectively. An upper adjusting bolt 172 passes through the upper through hole and engages with the upper threaded hole 1321. By adjusting the length of the upper adjusting bolt 172 screwed into the upper threaded hole 1321, the angle between the wing plate 132 and the side plate 171 is controlled, thereby controlling the tilt angle of the main shaft 12 in the second dimension. Correspondingly, a lower adjusting bolt 173 passes through the lower through hole and engages with the lower threaded hole. By adjusting the length of the lower adjusting bolt 173 screwed into the lower threaded hole, the angle between the wing plate 132 and the side plate 171 is controlled, thereby controlling the tilt angle of the main shaft 12 in the second dimension.

[0088] In one embodiment, at least one of the upper adjusting bolt 172 and the lower adjusting bolt 173 is provided with a temperature regulating component, which is used for rapid thermal compensation of the upper adjusting bolt 172 and the lower adjusting bolt 173. The structure of the temperature regulating component is the same as that of the temperature regulating component in the lower pad 152, and will not be described again here. In this embodiment, by providing a temperature regulating component, thermal compensation can be performed on the material of the upper adjusting bolt 172 and / or the lower adjusting bolt 173, preventing the adjusting bolts from deforming due to thermal expansion and contraction and changing the tilt angle of the spindle 12 in the second dimension, thereby affecting the grinding accuracy. This embodiment ensures the controllability and stability of the grinding process.

[0089] In this embodiment, the upper adjusting bolt 172 and the lower adjusting bolt 173 allow the wing plate 132 to swing at a small angle around the rotation axis 174 in a plane perpendicular to the rotation axis 174, thereby fine-tuning the tilt angle of the spindle seat 13 and the spindle 12 in the second dimension. The single-turn feed of the adjusting bolt can be set to 0.05mm, so the tilt angle adjustment accuracy of the spindle 12 in the second dimension can be controlled within 0.0001°. In other words, by adjusting the distance between the wing plate 132 and the side plate 171, which are distributed at two points above and below the rotation axis 174, the included angle between them can be adjusted to tilt the spindle 12. The structure is simple and easy to operate.

[0090] In one embodiment, the wafer thinning apparatus further includes an adjustment unit. This adjustment unit is used to decouple the unevenness δ1 and fullness δ2 based on the adjustment relationship between the tilt angle and surface features, and to determine a first-dimensional compensation angle and a second-dimensional compensation angle based on the surface features. First, the tilt angle of the main shaft 12 in the first dimension is adjusted based on the first-dimensional compensation angle, and then the tilt angle of the main shaft 12 in the second dimension is adjusted based on the second-dimensional compensation angle. The adjustment relationship between the tilt angle and surface features includes: a change in the tilt angle of the main shaft 12 in the first dimension causes a change in both the unevenness δ1 and fullness δ2; a change in the tilt angle in the second dimension causes a change in fullness δ2, while the unevenness δ1 remains unchanged. (See also...) Figure 5 , Figure 6 and Figure 10 The contact portion between the grinding wheel 11 and the wafer 50 forms an arc-shaped grinding line OM. One end O of the grinding line OM is located at the center of the wafer 50, and the other end M is located at the edge of the wafer 50. The first dimension is the radial direction Y' of the wafer 50 where both ends of the grinding line are located, and the second dimension is the horizontally extending direction X' perpendicular to the first dimension. When the tilt angle of the first dimension changes, the relative heights of points O, M, and M' all change, thus changing both the concavity / convexity δ1 and the fullness δ2. When the tilt angle of the second dimension changes, the relative heights of points O and M remain the same, while the relative height of point M' changes, thus changing the fullness δ2 and keeping the concavity / convexity δ1 unchanged. Figure 4 The diagram shows two dimensions in which the spindle tilt angle of the grinding device 10 is variable. The tilt angle adjustment of the spindle 12 in the first and second dimensions can be understood as pitch adjustment along arc b-b' and sway adjustment along arc a-a', respectively.

[0091] In one embodiment, the adjustment unit includes a monitoring module, a decision module, and an execution module. The monitoring module acquires the surface features of the wafer during the wafer thinning process. The decision module can decouple the concavity / convexity δ1 and fullness δ2 based on the adjustment relationship between the tilt angle and the surface features to adjust the tilt angle of the spindle 12 in the first dimension and / or the tilt angle in the second dimension. The decision module can also call a first model to read the surface features to determine the first-dimensional compensation angle and the second-dimensional compensation angle; the execution module can adjust the tilt angle of the spindle 12 in the first dimension and the second-dimensional tilt angle according to the first-dimensional compensation angle and the second-dimensional compensation angle, respectively. The first model is an arc-shaped model constructed based on the grinding lines formed when the grinding wheel contacts the wafer; the arc-shaped model is used to characterize the correspondence between the surface features and the tilt angles of the spindle 12 in the first and second dimensions.

[0092] In one embodiment, the adjustment unit is configured to:

[0093] Determine whether the concavity δ1 is less than the first threshold. If so, determine whether the fullness δ2 is less than the second threshold. Otherwise, call the first model to read the concavity δ1 and fullness δ2 to determine the first dimension compensation angle. The execution module adjusts the tilt angle of the spindle 12 in the first dimension based on the first dimension compensation angle. Then, after continuing grinding for a preset time, the monitoring module is triggered to continue the acquisition operation.

[0094] If the fullness δ2 is less than the second threshold, the monitoring module is triggered to continue the acquisition operation after the preset grinding time. Otherwise, the first model is called to read the concavity δ1 and fullness δ2 to determine the second dimension compensation angle. The execution module adjusts the tilt angle of the spindle 12 in the second dimension based on the second dimension compensation angle. Then, the monitoring module is triggered to continue the acquisition operation after the preset grinding time.

[0095] In one embodiment, the adjustment unit is electrically connected to the adjustment motor and is used to control the adjustment motor to drive the depth adjustment part 16 to rotate based on the first dimension compensation angle, so as to adjust the depth of the adjustment pad inserted between the feed mechanism 14 and the spindle seat 13, thereby adjusting the tilt angle of the spindle 12 in the first dimension.

[0096] In one embodiment, the adjustment unit can be electrically connected to the temperature control component, specifically, for determining the target temperature based on the first dimension compensation angle and the second model; the execution module can adjust the temperature of the temperature control component to make the temperature of the adjustment pad reach the target temperature, thereby causing the adjustment pad to deform due to temperature change, so as to adjust the tilt angle of the main shaft 12 in the first dimension.

[0097] In one embodiment, the temperature control component includes a temperature sensor and at least one temperature control actuator. Both the temperature sensor and the temperature control actuator are electrically connected to the adjustment unit, and the temperature sensor is used to monitor the temperature of the adjustment pad. After the execution module controls the temperature control component to adjust the temperature of the adjustment pad, the temperature sensor monitors the temperature of the adjustment pad, forming a closed-loop temperature control, which improves the accuracy of temperature control.

[0098] Reference Figure 9 This is a flowchart of a wafer thinning method provided in an embodiment of this application. The method uses the wafer thinning equipment of this application to perform grinding processing on the wafer, and includes the following steps:

[0099] S1. Obtain the surface features of the wafer during the wafer thinning process using a wafer thinning equipment. The surface features include: unevenness δ1 and fullness δ2.

[0100] In one embodiment, step S1 can be executed once at a preset time period, that is, grinding is paused after a preset grinding duration to monitor and acquire the surface features of the wafer once. In this embodiment, the monitored surface features of the wafer can be acquired from the monitoring components set in the wafer thinning equipment itself, or from the monitoring components of other equipment; this application does not impose specific limitations on this.

[0101] In one embodiment, the surface features of the wafer can be monitored by contact or non-contact measurement methods. Taking non-contact measurement as an example, it can be performed using an NCG (Non-contact Thickness Gauge). The NCG can be any of the following: a white light interferometer, a laser displacement sensor, or a spectral confocal displacement sensor, etc. This embodiment does not impose specific limitations on this.

[0102] In one embodiment, the monitoring process can select multiple feature radii (e.g., any integer from 5 to 10), such as five radii located at distances of 0.03R, 0.23R, 0.50R, 0.67R, and 0.90R from the center, where R represents the wafer radius. For each radius, multiple points (e.g., any integer from 20 to 30) are selected for thickness measurement. Data with significant deviations are discarded, and the average of the remaining thicknesses is taken as the thickness of that radius. Based on this thickness, the unevenness δ1 and fullness δ2 can be determined. For example, the difference between the thickness at the minimum radius and the thickness at the maximum radius is taken as the unevenness δ1, and the height difference between the maximum thickness and the center-edge line is taken as the fullness δ2.

[0103] S2. Based on the adjustment relationship between tilt angle and surface features, decouple concavity δ1 and fullness δ2 to adjust the tilt angle of the principal axis 12 in the first dimension and / or in the second dimension. The adjustment relationship between tilt angle and surface features includes: changes in the tilt angle in the first dimension cause changes in both concavity δ1 and fullness δ2, and changes in the tilt angle in the second dimension cause changes in fullness δ2 but no change in concavity δ1.

[0104] In one embodiment, the tilt angle refers to the tilt angle of the main axis 12 relative to the axis of the adsorption platform 20, that is, the tilt angle of the main axis 12 relative to the wafer axis. (See also...) Figure 5 , Figure 6 and Figure 10The contact portion between the grinding wheel 11 and the wafer 50 forms an arc-shaped grinding line OM. One end O of the grinding line OM is located at the center of the wafer 50, and the other end M is located at the edge of the wafer 50. The first dimension is the radial direction Y' of the wafer 50 where both ends of the grinding line are located, and the second dimension is the horizontally extending direction X' perpendicular to the first dimension. When the tilt angle of the first dimension changes, the relative heights of points O, M, and M' all change, thus changing both the concavity / convexity δ1 and the fullness δ2. When the tilt angle of the second dimension changes, the relative heights of points O and M remain the same, while the relative height of point M' changes, thus changing the fullness δ2 and keeping the concavity / convexity δ1 unchanged.

[0105] Existing spindle tilt adjustment methods fail to decouple concavity δ1 and fullness δ2, making it impossible to accurately obtain the adjustment amounts in both dimensions. When adjusting the spindle tilt to meet the concavity δ1 requirement, the fullness δ2 changes simultaneously; similarly, when adjusting the spindle tilt to meet the fullness δ2 requirement, the concavity δ1 changes simultaneously. Therefore, the adjustment process cannot simultaneously consider both concavity δ1 and fullness δ2, requiring repeated adjustments and attempts to simultaneously meet both requirements. Consequently, the adjustment rate is low, and adjustment accuracy cannot be guaranteed.

[0106] This application utilizes the adjustment relationship between tilt angle and surface features to decouple the convexity δ1 and fullness δ2, so that the convexity δ1 and fullness δ2 are no longer coupled. This avoids blind and inefficient adjustment of the tilt angle of the spindle 12 in two dimensions. The convexity δ1 and fullness δ2 can be used to obtain precise compensation angles in two dimensions respectively. First, the tilt angle in the first dimension is adjusted. Since the change in the tilt angle in the first dimension causes both the convexity δ1 and fullness δ2 to change, the convexity δ1 and fullness δ2 can be changed simultaneously when adjusting the tilt angle in the first dimension. By adjusting the tilt angle in the first dimension, at least the convexity δ1 can be ensured to meet the requirements, or both the convexity δ1 and fullness δ2 can be ensured to meet the requirements. In this case, there is no need to perform the second dimension tilt angle adjustment, which effectively improves the tilt angle adjustment efficiency and thus ensures the wafer grinding efficiency. Furthermore, when adjusting the second-dimensional tilt angle, the fullness δ2 is made to meet the requirements by adjusting the second-dimensional tilt angle, while keeping the already adjusted unevenness δ1 unaffected. This avoids the repeated and inefficient adjustment of unevenness δ1 and fullness δ2 by using the first-dimensional tilt angle and the second-dimensional tilt angle. This decoupled adjustment method has a clear and specific adjustment target and a reasonable and effective adjustment sequence. It not only improves the efficiency of tilt angle adjustment, but also improves the control accuracy of wafer unevenness δ1 and fullness δ2 during the adjustment process, thereby improving the TTV accuracy of wafer grinding.

[0107] refer to Figure 11 Here is a flowchart of another embodiment of the thinning method provided in this application, the method comprising:

[0108] S1. Obtain the surface features of the wafer during the wafer thinning process using a wafer thinning equipment. The surface features include: unevenness δ1 and fullness δ2.

[0109] The method for obtaining surface features in this step is the same as in the above embodiment, and will not be repeated here.

[0110] S21. Determine whether the concavity / convexity δ1 is less than the first threshold.

[0111] Based on the adjustment relationship between the tilt angle and surface features, it can be seen that changes in the tilt angle of the main axis 12 in the first dimension cause changes in both the concavity / convexity δ1 and the fullness δ2, while changes in the tilt angle in the second dimension cause changes in the fullness δ2 but no change in the concavity / convexity δ1. Therefore, in this embodiment, the first-dimensional tilt angle adjustment is performed first, that is, the first-dimensional tilt angle is adjusted so that the concavity / convexity δ1 meets the requirements. In this way, if the second-dimensional tilt angle needs to be adjusted later, it will not affect the concavity / convexity δ1, ensuring that the concavity / convexity δ1 can meet the requirements. Therefore, it is first determined whether the concavity / convexity δ1 is less than the first threshold; if yes, step S22 is executed; if no, step S25 is executed.

[0112] S22. Determine whether the fullness δ2 is less than the second threshold.

[0113] This step involves determining whether the fullness δ2 meets the requirements after confirming that the unevenness δ1 meets the requirements. If yes, then step S1 is executed after grinding for the preset time; otherwise, step S23 is executed.

[0114] S23. Call the first model to read the concavity δ1 and fullness δ2 to determine the second dimension compensation angle.

[0115] This step involves adjusting the tilt angle of the main axis 12 in the second dimension, provided that the fullness δ2 is not less than the second threshold. The first model is used to determine the compensation angle in the second dimension. The first model can be used to obtain the quantified compensation angle in the second dimension, thereby enabling precise adjustment of the main axis 12 in the second dimension.

[0116] S24. Adjust the tilt angle of the main axis 12 in the second dimension based on the second dimension compensation angle.

[0117] Then, after continuing grinding for the preset time, step S1 is executed.

[0118] S25. Call the first model to read the concavity δ1 and fullness δ2 to determine the first dimension compensation angle.

[0119] This step involves adjusting the tilt angle of the main axis 12 in the first dimension, provided that the concavity δ1 is not less than the first threshold. The first model is used to determine the compensation angle in the first dimension. The first model can be used to obtain the quantized compensation angle in the first dimension, thereby enabling precise adjustment of the main axis 12 in the first dimension.

[0120] S26. Adjust the tilt angle of the main axis 12 in the first dimension based on the first dimension compensation angle.

[0121] Then, after continuing grinding for the preset time, step S1 is executed.

[0122] In this embodiment, the first threshold and the second threshold can be set according to accuracy requirements; for example, the first threshold can be set to 0.8. The second threshold can be set to 0.6. .

[0123] In this embodiment, the first model is an arc-shaped model based on the grinding lines formed when the grinding wheel contacts the wafer. This arc-shaped model is used to characterize the correspondence between the surface features and the tilt angles of the principal axis 12 in the first and second dimensions. (Reference) Figure 10 This embodiment is a semi-contact grinding method, and the grinding line refers to the arc OM in the figure.

[0124] In one embodiment, reference Figure 10 The methods for constructing the first model include:

[0125] First, taking the center O' of the grinding wheel as the origin and the lower surface of the grinding wheel as the reference point... Plane, with the extension direction of principal axis 12 as In a coordinate system (not shown), construct the coordinates of the grinding line OM. :

[0126]

[0127] in, , Where is the radius of the grinding wheel; The radius of the wafer;

[0128] Secondly, a coordinate transformation is performed to obtain the tilt angle of principal axis 12 along the second dimension. and the tilt angle along the first dimension The coordinates (x, y, z) of the grinding line OM.

[0129]

[0130] in, This is the transformation matrix for the second dimension. This is the transformation matrix for the first dimension.

[0131] ,

[0132] Secondly, solve for the grinding wire OM around the center point of the wafer. O（ Rotation The following represents the arc coordinates of the wafer surface grinding morphology. ， .

[0133] Among them, the circular arc rotation matrix ;

[0134] Coordinates of wafer center point O ;

[0135] Finally, the arc surface can be constructed using software such as Matlab based on the arc surface coordinate expression. The resulting arc surface is the wafer surface shape. That is, the grinding wheel grinds the wafer based on the grinding line. The arc surface obtained after grinding 360° is the wafer surface shape. Then, the surface shape features of the wafer can be obtained based on the arc surface, thereby establishing the relationship between the surface shape features and the tilt angle of the principal axis 12 in the first and second dimensions.

[0136] In this embodiment, the first model can be pre-built, and then the tilt angle of the current principal axis 12 along the second dimension can be solved in reverse based on the surface features (undulation δ1 and fullness δ2) of the current wafer. θ x and the tilt angle along the first dimension θ y This allows for precise compensation angles in two dimensions, providing an accurate basis for adjusting the spindle tilt angle and effectively improving the accuracy of spindle tilt angle adjustment, thereby enhancing the precision of wafer grinding.

[0137] In one embodiment of this application, calling the first model to read the concavity δ1 and fullness δ2 to determine the first dimension compensation angle includes:

[0138] The first model is called to read the concavity δ1 and fullness δ2, and the tilt angle of the current principal axis 12 in the first dimension is obtained from the output of the first model; the first dimension compensation angle is determined based on the difference between the tilt angle of the current principal axis 12 in the first dimension and the preset first dimension target tilt angle.

[0139] Calling the first model to read the concavity δ1 and fullness δ2 to determine the second dimension compensation angle includes:

[0140] The first model is invoked to read the concavity δ1 and fullness δ2, and the tilt angle of the current principal axis 12 in the second dimension is obtained from the output of the first model; the second dimension compensation angle is determined based on the difference between the tilt angle of the current principal axis 12 in the second dimension and the preset target tilt angle in the second dimension.

[0141] In this embodiment, the preset first-dimensional target tilt angle and the preset second-dimensional target tilt angle can be determined based on the target surface features, that is, based on the target concavity / convexity δ1 and the target fullness δ2, and the first model. Therefore, the first-dimensional compensation angle can be determined based on the difference between the current main axis's tilt angle in the first dimension and the first-dimensional target tilt angle, and the second-dimensional compensation angle can be determined based on the difference between the current main axis's tilt angle in the second dimension and the second-dimensional target tilt angle. This embodiment automatically determines the compensation angles of the main axis 12 in two dimensions based on the first model, thereby allowing adjustment of the main axis tilt angle based on these two-dimensional compensation angles. This not only improves the accuracy of the compensation angle determination but also simplifies the process, requiring minimal computation, and helps improve the efficiency and timeliness of tilt angle adjustment.

[0142] In one embodiment of this application, adjusting the tilt angle of the principal axis 12 in the first dimension based on the first dimension compensation angle includes:

[0143] Input the first dimension compensation angle into the second model to determine the target temperature;

[0144] Adjust the temperature of the adjusting pad to reach the target temperature, so that the adjusting pad deforms accordingly based on the temperature change, thereby adjusting the tilt angle of the main shaft 12 in the first dimension.

[0145] In this embodiment, the tilt angle of the spindle in the first dimension can be adjusted by regulating the adjusting shim. The adjusting shim can be a wedge-shaped plate, and the insertion amount of the lower shim 152 can be controlled mechanically to achieve initial tilt angle adjustment. During the wafer grinding process, the temperature of the adjusting shim can be regulated by a temperature control component. After determining the target temperature, the temperature of the adjusting shim is adjusted to that target temperature. Utilizing the thermal expansion and contraction properties of the adjusting shim, corresponding deformation occurs based on temperature changes, thereby achieving ultra-fine compensation for the tilt angle of the spindle 12 in the first dimension. Since the coefficient of thermal expansion of the adjusting shim is fixed, the temperature change of the adjusting shim can be precisely controlled to cause corresponding deformation of the adjusting shim. The amount of deformation can be precisely controlled, thus achieving ultra-fine adjustment of the tilt angle of the spindle 12 in the first dimension.

[0146] Meanwhile, this embodiment realizes the automatic determination of the compensation angle based on the monitored surface features, and the automatic determination of the target temperature based on the determined compensation angle. Furthermore, the temperature adjustment component is used to automatically adjust the temperature of the adjustment pad. The fully automated closed-loop adjustment process avoids the delay problem and error problem caused by manual adjustment, and further improves the adjustment accuracy, thereby obtaining excellent wafer grinding TTV.

[0147] In one embodiment, there are two adjusting pads, namely an upper pad 151 and a lower pad 152. When both the upper pad 151 and the lower pad 152 are equipped with temperature regulating components, the second model is constructed as follows: based on the horizontal displacement of the upper pad 151 and the lower pad 152 at the upper support point 1511 and the lower support point 1522 respectively after the upper pad 151 and the lower pad 152 are deformed by heat, the tilt angle of the main shaft 12 after the upper pad 151 and the lower pad 152 are calculated in the first dimension. Then, based on the equality that the difference between the tilt angle of the main shaft 12 after the upper pad 151 and the lower pad 152 are deformed in the first dimension and the initial tilt angle of the main shaft 12 in the first dimension is equal to the first dimension compensation angle, the target temperature at which the lower pad 152 or the upper pad 151 deforms is solved.

[0148] When the compensation angle in the first dimension is greater than 0°, the tilt angle of the main shaft 12 in the first dimension needs to be increased, which means the thickness of the lower pad 152 needs to be increased so that the thermal deformation of the lower pad 152 is greater than that of the upper pad 151. At this time, the deformation caused by the thermal expansion of the lower pad 152 can be controlled, and there is no need to control the temperature of the upper pad 151. The temperature of the upper pad 151 is obtained by monitoring. Then, the second model can be used to solve the target temperature at which the lower pad 152 deforms and adjust the temperature of the lower pad 152 to the target temperature.

[0149] When the compensation angle in the first dimension is less than 0°, it is necessary to reduce the tilt angle of the spindle 12 in the first dimension. This can be achieved by making the upper pad 151 deformed by heat greater than the lower pad 152. By controlling the deformation of the upper pad 151 by heat, there is no need to control the temperature of the lower pad 152. The temperature of the lower pad 152 can be obtained by real-time monitoring. The second model can then be used to solve for the target temperature at which the upper pad 151 deforms and adjust the temperature of the upper pad 151 to the target temperature.

[0150] In one embodiment, the method for calculating the tilt angle of the spindle 12 in the first dimension after the thermal deformation of the upper pad 151 and the lower pad 152 at the upper support point 1511 and the lower support point 1522, respectively, includes:

[0151] First, based on the thermal expansion coefficient, temperature change, and thickness of the upper pad 151 at the upper support 1511, calculate the horizontal displacement of the upper pad 151 at the upper support 1511 after thermal deformation; then, based on the thermal expansion coefficient, temperature change, and thickness of the lower pad 152 at the lower support 1522, calculate the horizontal displacement of the lower pad 152 at the lower support 1522 after thermal deformation; based on the difference between the thickness of the lower pad 152 at the lower support 1522 and the thickness of the upper pad 151 at the upper support 1511 after thermal deformation, the initial distance between the upper support 1511 and the upper surface of the lower pad 152, and the length of the lower pad 152 along the main axis 12, solve for the tilt angle of the main axis 12 in the first dimension after the lower pad 152 or the upper pad 151 undergoes deformation.

[0152] In one embodiment, the method for constructing the second model includes:

[0153] S31. Determine the tilt angle of the initial principal axis 12 in the first dimension;

[0154] The initial tilt angle of the main spindle 12 in the first dimension is the tilt angle between the main spindle 12 and the axis of the adsorption platform 20 in the first dimension in the initial state, which is also the tilt angle between the main spindle 12 and the axis of the wafer 50 in the first dimension. The initial state is that neither the upper pad 151 nor the lower pad 152 has deformed.

[0155] S32. Calculate the horizontal displacement of the upper support 1511 after the upper pad 151 is deformed by heat.

[0156] After being heated, the upper pad 151 deforms in the horizontal direction, while the upper support 1511 and the lower support 1522 remain fixed in their relative positions in the vertical direction. The amount of horizontal displacement is related to the temperature change and the coefficient of thermal expansion of the upper pad 151.

[0157] S33: Calculate the horizontal displacement at the lower support point 1522 after the lower pad 152 is deformed by heat;

[0158] After being heated, the lower pad 152 deforms in the horizontal direction, while the upper support 1511 and the lower support 1522 remain fixed in their relative positions in the vertical direction. The amount of horizontal displacement is related to the temperature change and the coefficient of thermal expansion of the lower pad 152.

[0159] S34: Calculate the tilt angle of the main shaft 12 in the first dimension after the upper pad 151 and the lower pad 152 are deformed by heat;

[0160] The tilt angle of the spindle 12 in the first dimension after the upper pad 151 and the lower pad 152 are deformed by heat can be obtained based on: the thickness of the lower pad 152 at the lower support point 1522 after the heat deformation, the thickness of the upper pad 151 at the upper support point 1511 after the heat deformation, the initial distance between the upper support point 1511 and the upper surface of the lower pad 152, and the length of the lower pad 152 along the direction of the spindle 12.

[0161] S35: Based on the equality relationship that the difference between the initial tilt angle of the spindle 12 in the first dimension and the tilt angle of the spindle 12 in the first dimension after the upper pad 151 and the lower pad 152 are deformed by heat, the target temperature at which the lower pad 152 or the upper pad 151 deforms is calculated.

[0162] Due to the thermal deformation of the upper pad 151 and the lower pad 152, the tilt angle of the main shaft 12 in the first dimension Inclination angle with the initial principal axis 12 in the first dimension The difference is equal to the compensation angle (denoted as ). ), The results calculated in steps S31 and S34 Substituting into this formula, where, in Δ θ y When the temperature is greater than 0, it is necessary to control the thermal expansion of the lower pad 152 to increase the tilt angle of the spindle 12 in the first dimension. Temperature control of the upper pad 151 is not required. In this case, the temperature of the upper pad 151 can be obtained through real-time monitoring, such as using a temperature sensor. Because the grinding wheel 11 generates grinding heat during the wafer thinning process, this heat is conducted from the grinding wheel 11 to the spindle 12, causing the temperature of the upper pad 151 to be higher than room temperature during operation. Therefore, even without temperature control, the upper pad 151 will remain above room temperature, resulting in a temperature difference. In this case, the second model constructed in this embodiment can be used to solve for the target temperature at which the lower pad 152 deforms.

[0163] Similarly, in Δ θ y When the temperature is less than 0, it is necessary to control the thermal expansion of the upper pad 151 to reduce the tilt angle of the spindle 12 in the first dimension. No temperature control of the lower pad 152 is required. The temperature of the lower pad 152 can be obtained through real-time monitoring. During operation, the temperature of the lower pad 152 will be higher than room temperature. Therefore, even without temperature control, the lower pad 152 will remain above room temperature, resulting in a temperature difference. In this case, the second model constructed in this embodiment can be used to solve for the target temperature at which the upper pad 151 deforms.

[0164] It should be noted that since both the upper pad 151 and the lower pad 152 are located between the slider 142 and the wing plate 132, the deformation of the upper pad 151 and the lower pad 152 can be coordinated to adjust the tilt angle of the main shaft 12 in the first dimension. By controlling the thermal deformation of the lower pad 152, the tilt angle of the main shaft 12 in the first dimension can be increased; conversely, by controlling the thermal deformation of the upper pad 151, the tilt angle of the main shaft 12 in the first dimension can be decreased. Considering that heating to expand the adjusting pad is easier to achieve and has higher control precision than cooling to shrink the adjusting pad, this embodiment of the application uses the thermal expansion characteristic in both cases of increasing and decreasing the tilt angle of the main shaft 12 in the first dimension. By controlling the temperature of a single pad individually to adjust the tilt angle of the main shaft 12 in the first dimension, both adjustment efficiency and adjustment precision can be improved. This embodiment utilizes the characteristic that temperature rise is easier to control and has higher precision than temperature fall. It strategically selects the adjustment object to avoid adjustment lag or overshoot caused by factors such as unstable heat dissipation rate or ambient temperature interference during the cooling process, ensuring the stability of the temperature reaching the target value and thus guaranteeing the consistency of the pad deformation.

[0165] Through multiple experiments, it has been verified that using the thinning method of this application, the TTV precision of the ground wafer can reach less than 1μm, the adjustment precision of the first dimension compensation angle can reach 0.0001°, and the adjustment range of the first dimension angle is ±0.001°. Taking the copper wedge plate as an example, its adjustment precision in the first dimension can reach 0.00007°, and the adjustment range of the first dimension angle is ±0.0007°. The temperature adjustment range is controlled within ±20℃, and the temperature control precision is controlled within 2℃.

[0166] In this embodiment, the single-turn feed amount of the control bolt in the second dimension is 0.05mm, and the adjustment accuracy of the compensation angle in the second dimension can be controlled within 0.0001°.

[0167] This embodiment of the application determines the target temperature by inputting the first dimension compensation angle into the second model, thus more accurately obtaining the temperature value that needs to be adjusted. This embodiment of the application adjusts the temperature of the adjusting pad to the target temperature, causing the adjusting pad to deform accordingly based on the temperature change, thereby adjusting the spindle tilt angle. Utilizing the thermal expansion characteristics of materials, this is a non-mechanical contact adjustment method. Compared with traditional mechanical adjustment methods, it avoids adjustment errors and equipment failures caused by wear and loosening of mechanical parts, improving the stability and reliability of the equipment.

[0168] Reference Figure 12 The diagram shown is a structural block diagram of a thinning device provided in one embodiment of this application, including: a monitoring module 110, a decision module 111, and an execution module 112.

[0169] The monitoring module 110 is used to acquire the surface features of the wafer during the wafer thinning process of the wafer grinding equipment.

[0170] The decision module 111 is used to call the first model to read the surface features to determine the first dimension compensation angle and the second dimension compensation angle; the first model is an arc surface model constructed based on the grinding line formed when the grinding wheel contacts the wafer, and the arc surface model is used to characterize the correspondence between the surface features and the tilt angle of the main axis 12 in the first and second dimensions.

[0171] The execution module 112 is used to adjust the tilt angle of the main shaft 12 in the first dimension and the tilt angle in the second dimension based on the first dimension compensation angle and the second dimension compensation angle, respectively.

[0172] The further functions of the thinning device in this embodiment refer to the thinning method in the embodiment of this application, and will not be repeated here.

[0173] See Figure 13 , Figure 13 This is a schematic block diagram of an electronic device provided according to an embodiment of this application. Figure 13 The electronic device 600 in this embodiment may include one or more processors 601, one or more input devices 602, one or more output devices 603, and one or more memories 604. The processors 601, input devices 602, output devices 603, and memories 604 communicate with each other via a communication bus 605. The memory 604 stores computer programs, including program instructions. The processor 601 executes the program instructions stored in the memory 604. The processor 601 is configured to invoke the program instructions to perform the functions of the units in the above-described device embodiments, for example... Figure 12 The functions of the monitoring module 110, decision module 111, and execution module 112 shown are illustrated.

[0174] It should be understood that, in the embodiments of this application, the processor 601 may be a central processing unit, and the processor may also be other general-purpose processors, digital signal processors, application-specific integrated circuits, etc.

[0175] Input device 602 may include a touchpad, etc., and output device 603 may include a display, speaker, etc.

[0176] The memory 604 may include read-only memory and random access memory, and provides instructions and data to the processor 601. A portion of the memory 604 may also include non-volatile random access memory.

[0177] In specific implementations, the processor 601, input device 602, and output device 603 described in the embodiments of this application can execute the implementation methods described in the thinning method provided in the embodiments of this application. They can also execute the implementation methods of the electronic devices described in the embodiments of this application, which will not be elaborated further here.

[0178] In another embodiment of this application, a computer-readable storage medium is provided. This computer-readable storage medium stores a computer program, which includes program instructions. When executed by a processor, the program instructions implement all or part of the processes in the methods described above. Alternatively, the computer program can instruct related hardware to perform these processes. The computer-readable medium may include any entity or device capable of carrying computer program code, such as a USB flash drive, a portable hard drive, a computer memory, or a read-only memory.

[0179] The computer-readable storage medium can be an internal storage unit of the electronic device in any of the foregoing embodiments, such as a hard disk or memory of the electronic device. The computer-readable storage medium can also be an external storage device of the electronic device, such as a plug-in hard disk, smart memory card, etc., provided on the electronic device.

[0180] This application provides a computer program product, which includes computer-executable instructions or a computer program. The computer-executable instructions or computer program are stored in a computer-readable storage medium. The processor of an electronic device reads the computer-executable instructions from the computer-readable storage medium and executes the computer-executable instructions, causing the electronic device to perform the implementation described in the thinning method provided in this application.

[0181] It should be noted that, depending on the implementation needs, the various components / steps described in the embodiments of this application can be broken down into more components / steps, or two or more components / steps or parts of the operation of components / steps can be combined into new components / steps to achieve the purpose of the embodiments of this application.

[0182] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wafer thinning equipment, characterized in that, include: An adsorption platform is used to support and rotate the wafer. The grinding device, which is raised and lowered above the adsorption platform, includes: a grinding wheel for grinding wafers and a spindle connected to the grinding wheel for driving the grinding wheel to rotate. The ground wafer has surface features, including unevenness and fullness. An adjustment unit is used to decouple concavity and fullness based on the adjustment relationship between tilt angle and surface features, and to determine a first-dimensional compensation angle and a second-dimensional compensation angle based on surface features. First, the tilt angle of the main axis in the first dimension is adjusted based on the first-dimensional compensation angle, and then the tilt angle of the main axis in the second dimension is adjusted based on the second-dimensional compensation angle. The adjustment relationship between tilt angle and surface features includes: changes in the tilt angle of the main axis in the first dimension cause changes in both concavity and fullness, while changes in the tilt angle in the second dimension cause changes in fullness but no change in concavity. The control unit includes a monitoring module, a decision-making module, and an execution module. The control unit is configured as follows: Determine whether the concavity is less than the first threshold. If so, perform the operation of determining whether the fullness is less than the second threshold. Otherwise, call the first model to read the concavity and fullness to determine the first dimension compensation angle. The execution module adjusts the tilt angle of the spindle in the first dimension based on the first dimension compensation angle, and then triggers the monitoring module to continue the operation of acquiring the surface features of the wafer after the preset grinding time continues; If the fullness is less than the second threshold, the monitoring module is triggered to continue the operation of acquiring the surface features of the wafer after the preset grinding time is continued; otherwise, the first model is called to read the concavity and fullness to determine the second dimension compensation angle. The execution module adjusts the spindle tilt angle in the second dimension based on the second dimension compensation angle, and then triggers the monitoring module to continue the operation of acquiring the surface features of the wafer after the preset grinding time continues.

2. The wafer thinning equipment according to claim 1, characterized in that, The monitoring module is used to acquire the surface features of the wafer during the wafer thinning process of the wafer grinding equipment; The decision module is used to call the first model to read the surface features to determine the first dimension compensation angle and the second dimension compensation angle; the first model is an arc surface model constructed based on the grinding line formed when the grinding wheel contacts the wafer, and the arc surface model is used to characterize the correspondence between the surface features and the tilt angle of the main axis in the first and second dimensions; The execution module is used to adjust the tilt angle of the main shaft in the first dimension and the tilt angle in the second dimension based on the first dimension compensation angle and the second dimension compensation angle, respectively.

3. The wafer thinning equipment according to claim 2, characterized in that, The grinding device also includes a spindle seat, a feed mechanism, and an adjusting plate. The spindle is rotatably coaxially disposed within the spindle seat; the spindle seat is connected to the feed mechanism. The adjusting shim is at least partially inserted between the feed mechanism and the spindle seat, and the grinding device adjusts the insertion depth of the adjusting shim based on a first-dimensional compensation angle to adjust the tilt angle of the spindle in the first dimension.

4. The wafer thinning equipment according to claim 3, characterized in that, The regulating pad is equipped with a temperature regulating component; The adjustment unit is electrically connected to the temperature control component and is used to determine the target temperature based on the first dimension compensation angle and the second model. The execution module adjusts the temperature of the temperature control component to make the temperature of the adjustment pad reach the target temperature, so that the adjustment pad deforms based on the temperature change to adjust the tilt angle of the spindle in the first dimension.

5. The wafer thinning equipment according to claim 4, characterized in that, The adjusting pad includes an upper pad and a lower pad, which are inserted downward and upward respectively between the feed mechanism and the spindle seat, and the temperature regulating component is disposed on at least one of the upper pad and the lower pad.

6. The wafer thinning equipment according to claim 5, characterized in that, The temperature regulating component includes: The unit includes a temperature sensor and at least one temperature control actuator, both of which are electrically connected to the regulating unit. The temperature sensor is used to monitor the temperature of the regulating pad.

7. The wafer thinning equipment according to claim 1, characterized in that, The contact portion between the grinding wheel and the wafer forms an arc-shaped grinding line, with one end of the grinding line at the center of the wafer and the other end at the edge of the wafer. The first dimension is the direction of the wafer radius where both ends of the grinding line are located, and the second dimension is a horizontally extending direction perpendicular to the first dimension.

8. A thinning method, characterized in that, The method of grinding a wafer using the wafer thinning equipment according to any one of claims 1 to 7 includes the following steps: S1: Obtain the surface features of the wafer during the wafer grinding process of the wafer thinning equipment, the surface features including: unevenness and fullness; S2: Based on the adjustment relationship between tilt angle and surface features, decouple concavity and fullness to adjust the tilt angle of the principal axis in the first dimension and / or the tilt angle in the second dimension. The adjustment relationship between tilt angle and surface features includes: changes in the tilt angle in the first dimension cause changes in both concavity and fullness, and changes in the tilt angle in the second dimension cause changes in fullness but no change in concavity. S2 includes: S21: Determine whether the concavity is less than the first threshold. If so, execute S22. Otherwise, call the first model to read the concavity and fullness to determine the first dimension compensation angle, and adjust the tilt angle of the spindle in the first dimension based on the first dimension compensation angle. Then, after continuing grinding for a preset time, execute step S1. S22: Determine whether the fullness is less than the second threshold. If so, execute step S1 after continuing grinding for a preset time. Otherwise, call the first model to read the concavity and fullness to determine the second dimension compensation angle, and adjust the spindle tilt angle in the second dimension based on the second dimension compensation angle. Then, execute step S1 after continuing grinding for a preset time.

9. The thinning method according to claim 8, characterized in that, The first model is an arc surface model based on the grinding lines formed when the grinding wheel contacts the wafer. The arc surface model is used to characterize the correspondence between the surface features and the tilt angles of the principal axis in the first and second dimensions.

10. The thinning method according to claim 8, characterized in that, The step of calling the first model to read the concavity and convexity and the fullness to determine the first dimension compensation angle includes: The first model is invoked to read the concavity and saturation, and the tilt angle of the current principal axis in the first dimension is obtained from the first model output. The first dimension compensation angle is determined based on the difference between the current spindle tilt angle in the first dimension and the preset first dimension target tilt angle. The step of calling the first model to read the concavity and convexity and the fullness to determine the second dimension compensation angle includes: The first model is invoked to read the concavity and saturation, and the tilt angle of the current principal axis in the second dimension is obtained from the first model output. The second dimension compensation angle is determined based on the difference between the current spindle tilt angle in the second dimension and the preset target tilt angle in the second dimension.

11. The thinning method according to any one of claims 8 to 10, characterized in that, The grinding device includes a spindle seat, a feed mechanism, and an adjusting shim, wherein the adjusting shim is at least partially inserted between the feed mechanism and the spindle seat; adjusting the spindle tilt angle in the first dimension based on the first dimension compensation angle includes: The first dimension compensation angle is input into the second model to determine the target temperature; The temperature of the adjusting pad is adjusted to reach the target temperature, causing the adjusting pad to deform accordingly based on the temperature change, thereby adjusting the tilt angle of the spindle in the first dimension.

12. The thinning method according to claim 11, characterized in that, The adjusting pad includes an upper pad and a lower pad that are inserted downwards and upwards respectively between the spindle seat and the feed mechanism. The second model is constructed as follows: Based on the horizontal displacements of the upper and lower pads at the upper and lower supports respectively after thermal deformation, the tilt angle of the main shaft of the upper and lower pads after thermal deformation in the first dimension is calculated. Based on the equality relationship that the difference between the tilt angle of the main shaft of the upper and lower pads after thermal deformation in the first dimension and the initial tilt angle of the main shaft in the first dimension is equal to the compensation angle in the first dimension, the target temperature at which the deformation occurs in the lower or upper pad is determined.

13. The thinning method according to claim 12, characterized in that, The thinning method includes: When the first dimension compensation angle is greater than 0°, the target temperature at which the lower pad produces the deformation is calculated using the second model, and the temperature of the lower pad is adjusted to the target temperature. When the compensation angle in the first dimension is less than 0°, the target temperature at which the upper pad produces the deformation is calculated using the second model, and the temperature of the upper pad is adjusted to the target temperature.

14. The thinning method according to any one of claims 8 to 10, characterized in that, The adjustment precision of the first dimension compensation angle is 0.0001°.

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