Wafer thinning apparatus and thinning method

Abstract

The application provides a wafer thinning device and a thinning method, and belongs to the technical field of integrated circuit manufacturing; wherein the thinning method comprises: obtaining a surface shape feature of a wafer in a process of grinding the wafer by the wafer thinning device; determining a compensation angle of a main shaft based on the surface shape feature; inputting the compensation angle into a thermal expansion compensation angle model to obtain an output target temperature; adjusting the temperature of an adjusting pad plate to reach the target temperature, so that the adjusting pad plate generates corresponding deformation based on temperature change to adjust the inclination angle of the main shaft. The application improves the efficiency and grinding precision of wafer grinding.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of integrated circuit manufacturing, and more particularly to a wafer thinning device and a thinning method. BACKGROUND

[0002] Three-dimensional integrated circuit (3D IC) is an important technical 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 in the vertical direction, and realize electrical connection between layers through Through-Silicon Via (TSV) interconnection technology, so as to realize higher functional density in limited space.

[0003] Wafer thinning is a key supporting process in 3D IC manufacturing, and its main purpose is to thin the wafer from the original thickness to a super-thin state suitable for vertical integration. The super-thin wafer is the physical basis for realizing three-dimensional stacking, and is crucial for optimizing electrical performance and thermal management. With the increase of the number of 3D IC stacking layers, the requirement for the thinning thickness of a single wafer is increasingly stringent. At the same time, 3D IC puts forward very high requirements 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 the subsequent bonding process, thereby ensuring the yield of finished integrated circuit chips.

[0004] To achieve the above goal, wafer thinning equipment usually uses the physical grinding action of a grinding wheel to process super-thin wafers. Such equipment must precisely design and control its grinding structure and grinding process in order to meet the requirements of super-thin wafer processing (such as thickness ≤10μm, TTV ≤1.5μm and Ra ≤5nm) while taking into account manufacturing cost and production efficiency.

[0005] From the grinding structure, the pose of the spindle of the wafer thinning equipment directly affects the angle of contact between the grinding wheel and the wafer, so the adjustment of the spindle inclination angle can be used to adjust the surface shape characteristics of the wafer, thereby improving the grinding accuracy of the wafer. Currently, the industry usually only manually adjusts the spindle inclination angle before starting the wafer thinning equipment. On the one hand, due to the limitations of mechanical adjustment structure, the adjustment accuracy is low, and due to the different experiences of operators, human operation errors are brought in, so that the adjustment accuracy cannot be guaranteed, thereby affecting the wafer grinding accuracy. On the other hand, there is a delay in adjustment, which cannot respond in time to the wafer surface shape deviation to make timely adjustment of the spindle inclination angle to adjust the wafer surface shape by changing the cutting angle, resulting in gradual accumulation of wafer surface shape deviation and failure to make timely correction, ultimately making it difficult to meet the wafer grinding accuracy requirements and leading to a decrease in wafer yield. SUMMARY

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

[0007] In a first aspect, the present application provides a wafer thinning device, comprising: a grinding device, an adsorption platform, and a temperature control unit;

[0008] The adsorption platform is used to carry and rotate the wafer;

[0009] The grinding device is arranged above the adsorption platform, and the grinding device comprises: a main shaft for rotating the grinding wheel;

[0010] The grinding device further comprises: a main shaft seat, a feeding mechanism, and an adjusting pad, the main shaft is coaxially arranged in the main shaft seat and can rotate; the main shaft seat is connected to the feeding mechanism; the adjusting pad is at least partially inserted between the feeding mechanism and the main shaft seat; the adjusting pad is provided with a temperature adjusting component;

[0011] The temperature control unit is electrically connected to the temperature adjusting component, and is used to determine a compensation angle of the main shaft based on the surface shape characteristics of the wafer, input the compensation angle into a thermal expansion compensation angle model, obtain a target temperature output, adjust the temperature of the temperature adjusting component to make the temperature of the adjusting pad reach the target temperature, and make the adjusting pad generate corresponding deformation based on the temperature change to adjust the inclination angle of the main shaft.

[0012] In an embodiment, the main shaft seat comprises a tubular main body and wing plates extending outwardly and parallelly on the left and right sides of the main body; the feeding mechanism comprises a slide rail arranged in a vertical direction and a slide block moving vertically along the slide rail;

[0013] The adjusting pad is at least partially inserted between the slide block and the wing plates.

[0014] In an embodiment, the adjusting pad comprises: an upper pad and a lower pad, the upper pad and the lower pad are respectively inserted downwardly and upwardly between the slide block and the wing plates.

[0015] In an embodiment, the temperature adjusting component is arranged at least in one of the upper pad and the lower pad.

[0016] In an embodiment, the temperature adjusting component comprises:

[0017] A temperature sensor and at least one temperature control actuator, the temperature sensor and the temperature control actuator are electrically connected to the temperature control unit, and the temperature sensor is used to monitor the temperature of the adjusting pad.

[0018] In an embodiment, the thermal expansion compensation angle model is constructed as:

[0019] The target temperature at which the lower pad deforms is solved based on the horizontal displacement of the lower pad after thermal deformation at the lower fulcrum, the difference between the main shaft inclination angle after deformation of the lower pad and the initial main shaft inclination angle being equal to the amount of the compensation angle.

[0020] The target temperature at which the lower pad or the upper pad deforms is solved based on the horizontal displacement of the upper pad and the lower pad after thermal deformation at the upper fulcrum and the lower fulcrum, the difference between the main shaft inclination angle after thermal deformation of the upper pad and the lower pad and the initial main shaft inclination angle being equal to the amount of the compensation angle.

[0021] In a second aspect of the embodiments of the present application, a thinning method is provided, comprising:

[0022] Obtaining a surface profile feature of the wafer during grinding of the wafer by a wafer thinning device;

[0023] Determining a compensation angle of a main shaft based on the surface profile feature, the main shaft being connected to a grinding wheel of the wafer to drive the grinding wheel to rotate, and the main shaft being arranged in a main shaft seat;

[0024] Inputting the compensation angle into a thermal expansion compensation angle model to obtain an output target temperature;

[0025] Adjusting the temperature of an adjusting pad between the main shaft seat and the feed mechanism to the target temperature, so that the adjusting pad generates a corresponding deformation based on the temperature change to adjust the main shaft inclination angle.

[0026] In an embodiment, the adjusting pad comprises an upper pad and a lower pad respectively inserted downward and upward between the main shaft seat and the feed mechanism, and the thermal expansion compensation angle model is constructed as follows: the main shaft inclination angle after deformation of the lower pad is calculated based on the horizontal displacement of the lower pad after thermal deformation at the lower fulcrum, and the target temperature at which the lower pad deforms is solved based on the difference between the main shaft inclination angle after deformation of the lower pad and the initial main shaft inclination angle being equal to the amount of the compensation angle.

[0027] In an embodiment, the adjusting pad comprises an upper pad and a lower pad respectively inserted downward and upward between the main shaft seat and the feed mechanism, and the thermal expansion compensation angle model is constructed as follows: the main shaft inclination angle after thermal deformation of the upper pad and the lower pad is calculated based on the horizontal displacement of the upper pad and the lower pad after thermal deformation at the upper fulcrum and the lower fulcrum, and the target temperature at which the lower pad or the upper pad deforms is solved based on the difference between the main shaft inclination angle after thermal deformation of the upper pad and the lower pad and the initial main shaft inclination angle being equal to the amount of the compensation angle.

[0028] In an embodiment, the thermal expansion compensation angle model is constructed as follows:

[0029] The horizontal displacement of the upper pad at the upper fulcrum after thermal deformation is calculated based on the thermal expansion coefficient of the upper pad, the temperature change, and the thickness of the upper pad at the upper fulcrum;

[0030] The horizontal displacement of the lower pad at the lower fulcrum after thermal deformation is calculated based on the thermal expansion coefficient of the lower pad, the temperature change, and the thickness of the lower pad at the lower fulcrum;

[0031] The main shaft inclination angle of the lower pad or the upper pad after thermal deformation is solved based on the difference between the thickness of the lower pad at the lower fulcrum after thermal deformation and the thickness of the upper pad at the upper fulcrum after thermal deformation, the initial distance between the upper fulcrum and the upper surface of the lower pad, and the length of the lower pad along the main shaft direction.

[0032] In an embodiment, the thinning method comprises:

[0033] When the compensation angle is greater than 0°, the target temperature at which the lower pad is deformed is solved by the thermal expansion compensation angle model, and the temperature of the lower pad is adjusted to the target temperature;

[0034] When the compensation angle is less than 0°, the target temperature at which the upper pad is deformed is solved by the thermal expansion compensation angle model, and the temperature of the upper pad is adjusted to the target temperature.

[0035] In an embodiment, determining the compensation angle of the main shaft based on the surface shape feature comprises:

[0036] The surface shape feature is input into the camber surface model to obtain an output current main shaft inclination angle; the camber surface model is constructed based on a grinding line formed when the grinding wheel contacts the wafer, and the camber surface model is used to represent the corresponding relationship between the surface shape feature and the main shaft inclination angle;

[0037] The difference between the current main shaft inclination angle and the target inclination angle is determined as the compensation angle.

[0038] In an embodiment, the output current main shaft inclination angle comprises a first dimension inclination angle and a second dimension inclination angle; the contact part of the grinding wheel and the wafer forms an arc-shaped grinding line, one end of the grinding line is at the center of the wafer, and the other end is at the edge of the wafer; the first dimension is the wafer radius direction where the two ends of the grinding line are located, and the second dimension is the horizontal direction perpendicular to the first dimension;

[0039] The difference between the current main shaft inclination angle and the target inclination angle is determined as the compensation angle comprises:

[0040] The difference between the first dimension inclination angle and the first dimension target inclination angle is determined as the compensation angle.

[0041] The wafer thinning device and the thinning method provided by the embodiments of the present application have the following beneficial effects:

[0042] The present application can determine the compensation angle of the main shaft based on the surface shape characteristics of the wafer, input the compensation angle into a thermal expansion compensation angle model to obtain an output target temperature, and further adjust the temperature of the adjusting pad plate to reach the target temperature, so that the adjusting pad plate generates corresponding deformation based on the temperature change to adjust the inclination angle of the main shaft.

[0043] The present application realizes closed-loop control of the wafer grinding surface shape characteristics, eliminates the delay problem and uncertain factors of manual mechanical adjustment, significantly reduces the dependence of the adjustment result on the skills of the operator, reduces the errors caused by manual operation, effectively improves the overall efficiency of wafer grinding, and improves the wafer grinding precision.

[0044] The present application utilizes the thermal expansion and contraction property of the adjusting pad plate, accurately controls the temperature change of the adjusting pad plate, makes the adjusting pad plate generate corresponding deformation, thereby realizing ultra-fine adjustment of the inclination angle of the main shaft, avoiding the inherent step change of mechanical adjustment, and more finely and stably realizing stepless fine adjustment of the inclination angle of the main shaft, more accurately controlling the wafer grinding surface shape, and improving the wafer grinding precision, thereby providing technical support for ultra-high-density semiconductor stacking process. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0046] Figure 1 The structure schematic diagram of a wafer thinning device of an embodiment of the present application;

[0047] Figure 2 The surface shape characteristics schematic diagram of a wafer provided by an embodiment of the present application;

[0048] Figure 3 The surface shape characteristics schematic diagram of a wafer provided by another embodiment of the present application;

[0049] Figure 4 The structure schematic diagram of a grinding device in the present application; Figure 1

[0050] The structure schematic diagram of a grinding device in the present application; Figure 5 Figure 4 The left view of an embodiment of a grinding device in the present application;

[0051] Figure 6 The left view of another embodiment of a grinding device in the present application; Figure 4

[0052] Figure 7 ​​A thinning method flow chart provided by an embodiment of the present application;

[0053] Figure 8 A method flow chart for constructing a thermal expansion compensation angle model provided by an embodiment of the present application;

[0054] Figure 9 A method flow chart for constructing a thermal expansion compensation angle model provided by another embodiment of the present application;

[0055] Figure 10 A schematic diagram of a grinding wheel grinding wafer provided by an embodiment of the present application;

[0056] Figure 11 A structure block diagram of a thinning device provided by an embodiment of the present application;

[0057] Figure 12 A structure block diagram of an electronic device provided by an embodiment of the present application.

[0058] Reference signs:

[0059] 10, grinding device, 11, grinding wheel, 12, spindle, 13, spindle holder, 131, main body, 132, wing plate, 14, feeding mechanism, 141, slide rail, 142, slide block, 151, upper pad, 1511, upper fulcrum, 152, lower pad, 1521, horizontal part, 1522, lower fulcrum, 16, depth adjustment part, 20, adsorption platform, 30, workbench, 40, base, 50, wafer, 110, feature acquisition unit, 111, compensation angle determination unit, 112, target temperature determination unit, 113, inclination angle adjustment unit, 600, electronic device, 601, processor, 602, input device, 603, output device, 604, memory, 605, communication bus. DETAILED DESCRIPTION

[0060] In order to make the personnel in the art better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the specific embodiments of the present application, all other embodiments obtained by the person skilled in the art should belong to the scope of protection of the embodiments of the present application.

[0061] For the purpose of clarity, only the parts of the apparatus that are pertinent to the disclosure have been shown in the drawings, and they do not necessarily represent the actual configuration or structure of the apparatus. In addition, for the purpose of brevity and clarity, in some of the drawings, only one of a plurality of similar structures or components is shown, or only one of a plurality of similar structures or components is labeled. In this document, "a" or "an" can mean one or more than one unless otherwise indicated.

[0062] In this document, unless otherwise indicated or implied, the terms "mounting", "connected", "connection" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0063] In this application, unless otherwise specified and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. "Below", "below" and "below" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0064] In the description of the embodiments, the terms "up", "down", "left", "right", and other orientation or position relationships are based on the orientation or position relationships shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0065] In addition, in the description of the present application, the terms "first", "second" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0066] It should be understood that the terms "include", "comprise", or "have" used in the present application are intended to mean the presence of a certain element, but not excluding the presence or addition of one or more other elements, unless the context clearly indicates otherwise. In addition, "include" and / or "comprise" used herein indicate the presence of a shape, number, step, operation, member, element, and / or combination 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 the present application are described in detail below with reference to the accompanying drawings. The embodiments described below and the features in the embodiments can be combined with each other in the case of no conflict. The steps in the following method embodiments are only used for exemplary description, and are not used to limit the present application.

[0067] Figure 1 The structure of the wafer thinning device provided by an embodiment of the present application is shown, which includes a grinding device 10 and an adsorption platform 20, a workbench 30 for carrying and moving the adsorption platform 20, so that the grinding device 10 can act on the wafers 50 on different adsorption platforms 20, and the adsorption platform 20 can carry the wafers 50 by adsorption and drive the wafers 50 to rotate. Although not shown, the existing wafer thinning device usually supplies cooling water to the adsorption platform 20 and / or the wafer 50 to avoid the influence of heat-induced deformation on the final wafer 50 processing result, and the material of the adsorption platform 20 is also optimized in the prior art, such as using ceramic materials and / or invar alloys with low thermal expansion coefficients to reduce the influence of thermal deformation.

[0068] However, the grinding device 10 is arranged above the adsorption platform 20 in a lifting manner, and the heat that cannot be timely conducted and dissipated by the cooling water exists to be conducted upward to the grinding device 10, thereby affecting the pose factor of the grinding device 10. The grinding device 10 includes a spindle 12 and a grinding wheel 11, and the spindle 12 is coaxially connected with the grinding wheel 11 and drives the grinding wheel 11 to rotate. On the other hand, in the high-heat operation of grinding hard materials such as SiC, external cooling of the grinding device 10 can cause undesirable consequences such as insufficient cooling water acting on the grinding device 10 or serious overuse of total water.

[0069] The grinding wheel 11 can grind the wafer 50 during rotation, and a semi-contact grinding method can be used, that is, the grinding wheel 11 only contacts the area from the center to the edge of the wafer 50 to grind, and the wafer 50 has surface characteristics after grinding, including concave-convex degree and fullness. Figure 2 and Figure 3 are respectively examples of the concave-convex degree and fullness in the two cases of the outer convex surface shape and the inner concave surface shape, wherein δ 1 represents the concave-convex degree, and δ 2 represents the fullness.

[0070] In this application, the grinding wheel 11 can adjust the surface features of the wafer 50 while grinding the wafer 50. Specifically, this application adjusts the surface features of the wafer 50 by changing the angle between the grinding wheel 11 and the upper surface of the wafer 50 by adjusting the spindle tilt angle.

[0071] Reference Figure 4 and Figure 5 , Figure 4 for Figure 1 Schematic diagram of the intermediate grinding device 10 Figure 5 for Figure 4 Left view of the grinding device 10. The grinding device 10 also includes a spindle seat 13, a feed mechanism 14, and an adjusting pad. The spindle 12 is rotatably mounted in the spindle seat 13, and the spindle seat 13 is connected to the feed mechanism 14. The feed mechanism 14 can drive the spindle seat 13, the spindle 12, and the grinding wheel 11 to move up and down as a whole.

[0072] like Figure 4 and Figure 5 As shown, the adjusting pad is at least partially inserted between the feed mechanism 14 and the spindle seat 13. Specifically, the adjusting pad may include an upper pad 151 and a lower pad 152. The adjusting pad is provided with a temperature regulating component (not shown). The wafer thinning equipment also includes a temperature control unit. The temperature control unit is connected to the temperature regulating component to regulate the temperature of the temperature regulating component so that the temperature of the adjusting pad reaches the target temperature. The adjusting pad can produce corresponding deformation based on temperature changes in order to achieve ultra-fine adjustment of the spindle tilt angle.

[0073] In the traditional packaging field, the TTV requirement is generally between 1.5μm and 10μm, mainly considering the package size and heat dissipation performance. 3D IC stacking generally requires less than 1.5μm, but future stacking of more than 20 layers requires TTV to be less than 0.5μm or even 0.2μm. Therefore, the traditional method of adjusting the spindle tilt angle once before grinding is difficult to meet the extreme requirements of the new process for TTV. The new process requires real-time micro-adjustment of the spindle tilt angle during grinding.

[0074] When selecting the material for the adjusting pad, the effect of metal thermal creep need not be considered. This is because adjusting pads are usually made of high-strength materials such as carbon steel, and the creep initiation temperature is approximately (0.3~0.4) × T. m (K), approximately 229℃~396℃, far exceeding the operating temperature of the grinding wheel 11, and consequently far exceeding the operating temperature of the spindle 12 and spindle seat 13 cooled by cooling water (20℃ to 60℃), and from T / T m>0.3~0.4 this creep condition, also can exclude the influence of thermal field to adjust the pad plate strength. Because the thermal expansion coefficient of the adjusting pad plate is stable, so the corresponding deformation of the adjusting pad plate can be generated by accurately controlling the temperature change of the adjusting pad plate, and the deformation amount can be accurately controlled, so that the bidirectional ultra-fine adjustment of the main shaft inclination angle is realized by the independent contraction and / or expansion control of the upper pad plate 151 and the lower pad plate 152.

[0075] It should be noted that the thermal expansion coefficient of the material of the adjusting pad plate in contact with the main body part 131 should be greater than or equal to the thermal expansion coefficient of the main body part 131, and has high magnetic resistance (for example, containing copper, silver or graphite) and high compressive strength; In particular, considering that the thickness of the adjusting pad plate is small to reduce the overall volume of the grinding device 10 and control the accumulation of pollutants at the gap, the adjusting pad plate should be selected from a material with a bulk thermal expansion coefficient greater than 16×10 -6 / ℃, the compressive strength is greater than 500MPa, and preferably a composite material of metal and non-metal; Further, in order to achieve better thermal expansion effect, it is preferred to use a composite material containing ABS plastic, including high modulus carbon fiber / epoxy resin, high temperature thermoplastic carbon fiber / PEEK.

[0076] In one embodiment, the temperature control unit is used to determine the compensation angle of the main shaft 12 based on the surface shape characteristics of the wafer 50, input the compensation angle into the thermal expansion compensation angle model, obtain the output target temperature, adjust the temperature of the temperature adjusting component (not shown) to make the temperature of the adjusting pad plate reach the target temperature, and make the adjusting pad plate generate corresponding deformation based on the temperature change, and then adjust the main shaft inclination angle.

[0077] Although there are many components with temperature adjustment function in general field, in the present embodiment, considering that the gap cannot be too wide to avoid introducing pollutants and other factors, the thickness of the adjusting pad plate cannot be increased too much compared with the prior art. The adjustment of the main shaft inclination angle can be completed by the cooperation of the upper pad plate 151 and the lower pad plate 152, and in the present embodiment, the temperature adjusting components acting on the upper pad plate 151 and the lower pad plate 152 can cooperatively realize the functions of heating and cooling (for example, the upper pad plate 151 is heated and expanded, and the lower pad plate 152 is cooled and contracted).

[0078] The temperature adjusting component having both heating and cooling functions includes Peltier, vortex tube and the like, and the upper pad 151 and the lower pad 152 can share one temperature adjusting component, so that the heating energy and the cooling energy are transmitted respectively, thereby saving space and volume and avoiding the introduction of pollutants. In the embodiment, the target temperature is obtained by the thermal expansion compensation angle model, and then the temperature of the adjusting pad is adjusted to the target temperature by the temperature adjusting component, and then the deformation amount of the adjusting pad is controlled to adjust the spindle inclination angle, so that the precision control of the spindle inclination angle can reach 0.0001°. For example, in the case of a temperature control accuracy of 2℃, the precision control of the spindle inclination angle is 0.0001°, which is much higher than the 0.01° that can be achieved by the conventional mechanical adjustment mode (such as screw, wedge, etc.). The adjustment of the spindle inclination angle by the temperature control of the adjusting pad can be monitored and adjusted in real time, and the continuous and smooth adjustment characteristic avoids the inherent step change of the mechanical adjustment, so that the stepless ultra-fine adjustment of the spindle inclination angle can be realized more finely and stably, and the ultra-fine adjustment of the wafer grinding surface shape can be controlled more accurately. Further, through the automatic control of the temperature adjusting component, the human uncertainty is greatly reduced, the dependence of the adjustment result on the operator's skill is significantly reduced, the adjustment operation error is reduced, and the wafer grinding precision is further improved.

[0079] In one embodiment, as shown in Figure 4 , the feeding mechanism 14 includes two vertical slide rails 141 and two slide blocks 142 movably arranged on the slide rails 141 in the vertical direction. The slide rails 141 are fixed on the base 40 of the wafer thinning device. The spindle holder 13 includes a tubular main body 131 and two wing plates 132 extending outwardly and parallel to each other on the left and right sides of the main body 131, and the spindle 12 is coaxially arranged in the main body 131 and can rotate. The wing plates 132 are parallel to the outer sides of the slide blocks 142, and the two wing plates 132 are connected to the two slide blocks 142 respectively, so that the spindle holder 13 and the spindle 12 as a whole can move in the vertical direction along the slide rails 141, thereby driving the grinding wheel 11 to ascend and descend. In the embodiment, the adjustment of the spindle inclination angle refers to the forward and backward pitch adjustment of the spindle 12 along the arc b-b', and the arc a-a' represents that the spindle 12 can swing left and right along the arc, and the adjustment of the left and right swing is not specifically limited. Figure 4

[0080] As shown in Figure 4 and Figure 5 , the adjusting pad is arranged between the wing plate 132 and the slide block 142, and the depth of the adjusting pad inserted between the wing plate 132 and the slide block 142 changes the distance between the wing plate 132 and the slide block 142, thereby changing the spindle inclination angle. In a specific embodiment, as shown in Figure 5 ​As shown, there are two sets of adjusting shims: an upper shim 151 and a lower shim 152. One or both of the upper shim 151 and the lower shim 152 can be wedge-shaped plates, allowing for mechanical adjustment of the spindle 12's pitch by adjusting the insertion depth of the wedge-shaped plates. The upper shim 151 and the lower shim 152 are inserted downwards and upwards, respectively, between the feed mechanism 14 and the spindle seat 13.

[0081] In one embodiment, such as Figure 4 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 adjusting motor (not shown). For example, the adjusting motor can be controlled to rotate according to a compensation angle, thereby achieving automatic adjustment of the spindle tilt angle. In this embodiment, the thickness variation rate of the lower pad 152 along the vertical direction can be set according to process requirements, thereby controlling the adjustment accuracy of the spindle tilt angle.

[0082] In another embodiment of this application (not limiting), a temperature regulating component is provided in at least one of the upper pad 151 and the lower pad 152. In one embodiment, the upper pad 151 is made of a material with a very low coefficient of thermal expansion, so the thermal deformation of the upper pad 151 can be ignored. Only the lower pad 152 is provided with a temperature regulating component, which can control the temperature of the lower pad 152. The lower pad 152 has the property of thermal expansion and contraction. After thermal expansion, the lower pad 152 will change the distance between the lower position of the wing plate 132 and the slider 142, that is, the lower pad 152 will deform in the horizontal direction, thereby realizing the fine adjustment of the spindle tilt angle. The deformation caused by the temperature change of the lower pad 152 is usually much smaller than the adjustment amount of mechanical adjustment. This embodiment utilizes the property of thermal expansion and contraction of the lower pad 152 to adjust the spindle tilt angle by adjusting the temperature of the lower pad 152, with high adjustment accuracy, reaching 0.0001°.

[0083] Non-limiting, 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 and the lower pad 152, the spindle tilt angle can be reduced or increased, thereby minimizing the adjustment amount of each adjusting pad or maximizing the adjustment range. See also Figure 5As shown, when the thickness of the upper pad 151 changes, the thickness of the upper pad 151 at the upper fulcrum 1511 changes, and the thickness change direction is as shown by the horizontal arrow Figure 5 As shown by the horizontal arrow, the spindle holder 13 rotates in the first direction by an angle n, thereby increasing the angle of the forward inclination of the spindle 12. As shown by the horizontal arrow Figure 6 As shown, when the thickness of the lower pad 152 changes, the thickness of the lower pad 152 at the lower fulcrum 1522 changes, and the thickness change direction is as shown by the horizontal arrow Figure 6 As shown by the horizontal arrow, the spindle holder 13 rotates in the first direction by an angle m, thereby increasing the angle of the backward inclination of the spindle 12. It should be noted that the upper fulcrum 1511 is the position where the upper end of the upper pad 151 contacts the wing plate 132. When the upper pad 151 is a wedge-shaped plate, the upper fulcrum 1511 is always the position where the thickness of the upper pad 151 is the largest. The lower fulcrum 1522 is the position where the lower end of the lower pad 152 contacts the wing plate 132. When the lower pad 152 is a wedge-shaped plate, the lower fulcrum 1522 is always the position where the thickness of the lower pad 152 is the largest. When temperature adjustment is performed, the vertical positions of the upper fulcrum 1511 and the lower fulcrum 1522 do not change, and the distance between the upper fulcrum 1511 and the lower fulcrum 1522 in the vertical direction does not change.

[0084] It should be noted that the present application can combine the adjustment method of adjusting the inclination angle by the depth adjustment part 16 and the adjustment method of adjusting the inclination angle by the temperature adjustment part. The depth adjustment part 16 adjusts the depth of the adjustment pad inserted between the wing plate 132 and the slider 142 for coarse adjustment of the inclination angle, and the temperature adjustment part adjusts the temperature of the adjustment pad to adjust the inclination angle by deforming the adjustment pad for fine adjustment of the inclination angle of the spindle. The combination of coarse adjustment and fine adjustment can balance the adjustment efficiency and the adjustment accuracy, and reduce the adjustment deviation and the cumulative error.

[0085] In an embodiment, the temperature adjustment part includes a temperature sensor and at least one temperature control actuator. 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. The temperature sensors of the upper pad 151 and the lower pad 152 are arranged on the surface thereof. Further, for the adjustment pad made of a metal and a non-metal composite material, the temperature sensor is preferably arranged on the surface or in the interior of the side away from the temperature control actuator. After the temperature adjustment unit controls the temperature adjustment part to adjust the temperature of the adjustment pad, the temperature sensor monitors the temperature of the adjustment pad, forming a closed-loop control of the temperature, and improving the accuracy of the temperature control.

[0086] Considering that the strategy of cooperative adjustment of the two adjustment pads is relatively complex, the adjustment method is described below by an embodiment of separate adjustment of the lower pad 152.

[0087] Referring toFigure 7 , Figure 7 A wafer thinning method flow chart is provided for an embodiment of the present application, the method uses the wafer thinning device of the present application to grind the wafer, including the following steps:

[0088] S1: Obtain the surface profile characteristics of the wafer during the wafer grinding process.

[0089] In an embodiment, the wafer thinning device can also include a monitoring assembly, and the surface profile characteristics of the wafer can be obtained through the monitoring assembly at a preset frequency, that is, step S1 is executed cyclically every certain time interval.

[0090] In another embodiment, the surface profile characteristics of the wafer during the wafer grinding process can also be obtained by an external monitoring device, which is consistent with the foregoing, and the surface profile characteristics of the wafer should also be obtained at a preset frequency. The preset frequency can be set by the person skilled in the art based on experience.

[0091] In an embodiment, the surface profile characteristics of the wafer can be monitored by contact or non-contact measurement. Taking non-contact measurement as an example, it can be measured by NCG (Non-contact Thickness Gauge). The NCG can be any one of a white light interferometer, a laser displacement sensor, or a spectral confocal displacement sensor, and the present embodiment does not make specific limitations.

[0092] In an embodiment, the monitoring process can select a plurality of (for example, any integer between 5 and 10) characteristic radii, for example, 5 radii at positions 0.03R, 0.23R, 0.50R, 0.67R, and 0.90R from the center, R represents the radius of the wafer, a plurality of (for example, any integer between 20 and 30) points are selected for thickness measurement for each radius, the data with obvious deviation is removed, and the average value of the remaining thickness is taken as the thickness of the radius. Based on the thickness, the concave-convex degree δ 1 and the fullness degree δ 2 can be determined. For example, the thickness difference between the minimum radius and the maximum radius is taken as the concave-convex degree δ 1, and the height difference of the maximum thickness from the center-edge line is taken as the fullness degree δ 2.

[0093] S2: Determine the compensation angle of the main shaft 12 based on the surface profile characteristics. The main shaft 12 is connected with the grinding wheel 11 of the wafer grinding to drive the grinding wheel 11 to rotate, and the main shaft 12 is arranged in the main shaft seat 13.

[0094] The compensation angle of the main shaft 12 refers to the inclination angle to be adjusted of the main shaft 12.

[0095] ​In an embodiment, the method for determining the compensation angle of the spindle 12 based on the surface profile includes:

[0096] The surface profile obtained in step S1 can be input into a pre-constructed cambered surface model to obtain the current spindle inclination angle. The difference between the current spindle inclination angle and the target inclination angle is determined as the compensation angle of the spindle 12. The cambered surface model is constructed based on the grinding line formed when the grinding wheel 11 contacts the wafer, and is used to represent the correspondence between the surface profile and the spindle inclination angle.

[0097] S3: input the compensation angle into the thermal expansion compensation angle model to obtain the output target temperature.

[0098] In an embodiment, the compensation angle calculated in step S2 can be input into a pre-constructed thermal expansion compensation angle model to determine the target temperature, which is the temperature that the adjusting pad needs to reach after temperature adjustment.

[0099] In an embodiment, if the adjusting pad includes an upper pad 151 and a lower pad 152, and the upper pad 151 is made of a material that is not easily deformed by heat, i.e., the thermal expansion coefficient of the upper pad 151 is small (the thermal expansion coefficient of the upper pad 151 is less than or equal to a pre-set thermal expansion coefficient threshold), then the deformation amount of the upper pad 151 can be ignored, and the spindle inclination angle can be adjusted only by changing the temperature of the lower pad 152. At this time, the thermal expansion compensation angle model is constructed as follows: based on the horizontal displacement of the lower pad 152 at the lower fulcrum 1522 after thermal deformation, the spindle inclination angle of the lower pad 152 after thermal deformation is calculated, and then based on the difference between the spindle inclination angle of the lower pad 152 after thermal deformation and the initial spindle inclination angle being equal to the compensation angle, the target temperature at which the lower pad 152 deforms is solved.

[0100] In an embodiment, the horizontal displacement of the lower pad 152 at the lower fulcrum 1522 after thermal deformation can be calculated based on the thermal expansion coefficient of the lower pad 152, the temperature change, and the thickness (before thermal deformation) of the lower pad 152 at the lower fulcrum 1522. And based on the thickness of the lower pad 152 at the lower fulcrum 1522 after thermal deformation, the thickness of the upper pad 151 at the upper fulcrum 1511, the initial distance between the upper fulcrum 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, the spindle inclination angle of the lower pad 152 after thermal deformation is solved.

[0101] Corresponding to the above embodiment in which the deformation amount of the upper pad 151 is ignored, an embodiment of the present application provides a method for constructing a thermal expansion compensation angle model, which is described with reference to Figure 8 To construct the flow chart of the thermal expansion compensation angle model method, the following steps are included:

[0102] S21, determine the initial spindle inclination angle;

[0103] The initial spindle inclination angle is the inclination angle of the spindle 12 with respect to the axis of the chucking platform 20 in the initial state, i.e., the inclination angle of the spindle 12 with respect to the axis of the wafer 50, and the initial state is the state in which the adjusting pad has not been deformed, which can be understood as the state at the ambient temperature or room temperature of the wafer thinning device.

[0104] In the embodiment, the initial spindle inclination angle The initial spindle inclination angle can be obtained based on the following relationship:

[0105] ;

[0106] wherein, represents the thickness of the lower pad 152 at the lower fulcrum 1522 (the horizontal thickness of the lower pad 152 when not deformed by heat); represents the thickness of the upper pad 151 at the upper fulcrum 1511 (the horizontal thickness of the upper pad 151 when not deformed by heat); represents the initial distance between the upper fulcrum 1511 and the upper surface of the lower pad 152; represents the length of the lower pad 152 along the direction of the spindle 12.

[0107] The embodiment is described by taking the example that the lower pad 152 is just fully inserted between the feeding mechanism 14 and the spindle seat 13 (i.e., the lower surface of the lower pad 152 is in the same plane as the lower fulcrum), and if the lower pad 152 is partially inserted between the feeding mechanism 14 and the spindle seat 13, the corresponding represents the length of the portion of the lower pad 152 inserted between the feeding mechanism 14 and the spindle seat 13 along the direction of the spindle 12, and if the lower pad 152 is a wedge-shaped plate, the wedge-shaped portion is ensured to be fully inserted, and the lowermost end of the portion of the lower pad 152 inserted between the feeding mechanism 14 and the spindle seat 13 is a non-wedge-shaped portion.

[0108] S22, calculate the horizontal displacement of the lower pad 152 at the lower fulcrum 1522 after being deformed by heat;

[0109] The lower pad 152 is deformed in the horizontal direction after being deformed by heat, and the relative position between the upper fulcrum 1511 and the lower fulcrum 1522 is fixed in the vertical direction. The horizontal displacement is related to the temperature change and the thermal expansion coefficient of the lower pad 152, and the horizontal displacement of the lower pad 152 can be calculated using the following relationship:

[0110] ;

[0111] wherein, represents the thermal expansion coefficient of the lower pad 152, ​represents the temperature of the lower pad 152, i.e. the target temperature, represents the initial temperature, i.e. the initial temperature of the lower pad 152, represents the thickness of the lower pad 152 at the lower fulcrum 1522, which is the thickness in the horizontal direction when the lower pad 152 is not deformed. Wherein refers to the room temperature, i.e. the ambient temperature of the wafer thinning device when it is not started, which can be a fixed value.

[0112] S23, calculating the main shaft inclination angle of the lower pad 152 after thermal deformation;

[0113] Since the transverse thickness of the lower pad 152 changes after thermal expansion, i.e. the horizontal displacement, the vertical distance between the upper fulcrum 1511 and the lower fulcrum 1522 remains unchanged, and the deformation of the upper pad 151 is ignored in this embodiment, therefore, the main shaft inclination angle of the lower pad 152 after thermal deformation is which can be calculated using the following relationship:

[0114] .

[0115] S24, based on the difference between the main shaft inclination angle of the lower pad 152 after thermal deformation and the initial main shaft inclination angle being equal to the compensation angle, solving the target temperature of the lower pad 152 corresponding to the thermal deformation.

[0116] Let the compensation angle be , using the relationship of , the calculated in the above steps S21 and S23 is brought into this formula, and the only unknown .

[0117] In this embodiment, the compensation angle determined in step S2 can be input into the thermal expansion compensation angle model constructed by the method, and the target temperature can be obtained.

[0118] For ease of understanding, in the above embodiment, the upper pad 151 adopts a material with a small thermal expansion coefficient, so that the deformation of the upper pad 151 after heating can be ignored, and only by controlling the temperature change of the lower pad 152, the lower pad 152 is heated to produce corresponding deformation to adjust the main shaft inclination angle. Since the thermal expansion coefficient of the lower pad 152 is fixed under the condition that the Curie temperature is far lower than the Curie temperature, the thermal deformation amount is fixed under the condition that the temperature change is determined, therefore, as long as the temperature change amount of the lower pad 152 is accurately controlled, the adjustment of the main shaft inclination angle can be realized, and by selecting the material of the lower pad 152 with different thermal expansion coefficients, the adjustment accuracy of the main shaft inclination angle can be controlled, so that the ultra-fine adjustment of the main shaft inclination angle can be realized.

[0119] In another embodiment, considering that it is more difficult to achieve the cold shrinkage of the material by cooling, and the adjustment of the spindle inclination angle can include both the increase and the decrease of the inclination angle, for this purpose, the upper pad plate 151 and the lower pad plate 152 can both adopt a material that expands when heated, and the adjustment of the spindle inclination angle in both the increase and the decrease directions can be achieved by cooperating the upper pad plate 151 or the lower pad plate 152, and the thermal expansion compensation angle model constructed for this embodiment is:

[0120] Based on the horizontal displacement amounts of the upper pad plate 151 and the lower pad plate 152 at the upper fulcrum 1511 and the lower fulcrum 1522 respectively after thermal deformation, the spindle inclination angle after thermal deformation of the upper pad plate 151 and the lower pad plate 152 is calculated, and then based on the difference between the spindle inclination angle after thermal deformation of the upper pad plate 151 and the lower pad plate 152 and the initial spindle inclination angle being equal to the amount of the compensation angle, the target temperature at which the lower pad plate 152 and / or the upper pad plate 151 deforms is solved.

[0121] Wherein, when the compensation angle is greater than 0°, that is, the spindle inclination angle needs to be increased, that is, the thickness of the lower pad plate 152 needs to be increased, and the thermal deformation of the lower pad plate 152 is greater than that of the upper pad plate 151, at this time, the lower pad plate 152 can be controlled to deform by thermal expansion, and the upper pad plate 151 does not need to be temperature controlled, the temperature of the upper pad plate 151 is obtained by monitoring, and then the thermal expansion compensation angle model can be used to solve the target temperature at which the lower pad plate 152 deforms;

[0122] When the compensation angle is less than 0°, that is, the spindle inclination angle needs to be reduced, at this time, it can be realized by making the thermal deformation of the upper pad plate 151 greater than that of the lower pad plate 152, by controlling the upper pad plate 151 to deform by thermal expansion, the lower pad plate 152 does not need to be temperature controlled, and the temperature of the lower pad plate 152 can be obtained by real-time monitoring, then the thermal expansion compensation angle model can be used to solve the target temperature at which the upper pad plate 151 deforms.

[0123] In one embodiment, based on the horizontal displacement amounts of the upper pad plate 151 and the lower pad plate 152 at the upper fulcrum 1511 and the lower fulcrum 1522 respectively after thermal deformation, the method for calculating the spindle inclination angle after thermal deformation of the upper pad plate 151 and the lower pad plate 152 includes:

[0124] The horizontal displacement amount of the upper cushion plate 151 at the upper fulcrum 1511 after thermal deformation is calculated based on the thermal expansion coefficient of the upper cushion plate 151, the temperature change, and the thickness of the upper cushion plate 151 at the upper fulcrum 1511; and the horizontal displacement amount of the lower cushion plate 152 at the lower fulcrum 1522 after thermal deformation is calculated based on the thermal expansion coefficient of the lower cushion plate 152, the temperature change, and the thickness of the lower cushion plate at the lower fulcrum 1522; the main shaft inclination angle after deformation of the lower cushion plate 152 or the upper cushion plate 151 is solved based on the difference between the thickness of the lower cushion plate 152 at the lower fulcrum 1522 after thermal deformation and the thickness of the upper cushion plate 151 at the upper fulcrum 1511 after thermal deformation, the initial distance between the upper fulcrum 1511 and the upper surface of the lower cushion plate 152, and the length of the lower cushion plate 152 in the direction of the main shaft 12.

[0125] Corresponding to the above-mentioned upper cushion plate 151 and lower cushion plate 152 considering thermal deformation, an embodiment of the present application provides a method for constructing a thermal expansion compensation angle model, referring to Figure 9 The flowchart of the method for constructing the thermal expansion compensation angle model includes the following steps:

[0126] S31, determine the initial main shaft inclination angle;

[0127] The initial main shaft inclination angle is the inclination angle between the main shaft 12 and the axis of the adsorption platform 20 in the initial state, that is, the inclination angle between the main shaft 12 and the axis of the wafer 50. The initial state is the state in which the upper cushion plate 151 and the lower cushion plate 152 are not deformed, which can also be understood as the state at the ambient temperature or room temperature of the wafer thinning device.

[0128] In the embodiment, the initial main shaft inclination angle The initial main shaft inclination angle can be obtained based on the following relationship:

[0129] ;

[0130] Wherein, represents the thickness of the lower cushion plate at the lower fulcrum 1522 (the horizontal direction thickness of the lower cushion plate 152 without thermal deformation); represents the thickness of the upper cushion plate 151 at the upper fulcrum 1511 (the horizontal direction thickness of the upper cushion plate 151 without thermal deformation); represents the initial distance between the upper fulcrum 1511 and the upper surface of the lower cushion plate 152; represents the length of the lower cushion plate 152 in the direction of the main shaft 12.

[0131] The present embodiment is described by taking the example that the lower pad plate 152 is completely inserted between the feeding mechanism 14 and the spindle seat 13 (i.e. the lower surface of the lower pad plate 152 is in the same plane as the lower fulcrum), if the lower pad plate 152 is partially inserted between the feeding mechanism 14 and the spindle seat 13, the corresponding represents the length of the portion of the lower pad plate 152 inserted between the feeding mechanism 14 and the spindle seat 13 in the direction of the spindle 12, and if the lower pad plate 152 is a wedge-shaped plate, the wedge-shaped portion is ensured to be completely inserted, and the lowermost end of the portion of the lower pad plate 152 inserted between the feeding mechanism 14 and the spindle seat 13 is a non-wedge-shaped portion.

[0132] S32, calculate the horizontal displacement amount of the upper pad plate 151 after thermal deformation at the upper fulcrum 1511;

[0133] The upper pad plate 151 is deformed in the horizontal direction after thermal deformation, and the relative position of the upper fulcrum 1511 and the lower fulcrum 1522 in the vertical direction is fixed. The horizontal displacement amount of the upper pad plate 151 is related to the temperature change and the thermal expansion coefficient of the upper pad plate 151, and the horizontal displacement amount of the upper pad plate 151 can be calculated using the following relationship :

[0134] ;

[0135] wherein, represents the thermal expansion coefficient of the upper pad plate 151, represents the temperature of the upper pad plate 151, represents the initial temperature, i.e. the initial temperature of the upper pad plate 151 and the lower pad plate 152, i.e. the environmental temperature in which the wafer thinning device is in the state of being not started, and the temperature value can be a fixed value;

[0136] S33: calculate the horizontal displacement amount of the lower pad plate 152 after thermal deformation at the lower fulcrum 1522;

[0137] The lower pad plate 152 is deformed in the horizontal direction after thermal deformation, and the relative position of the upper fulcrum 1511 and the lower fulcrum 1522 in the vertical direction is fixed. The horizontal displacement amount of the lower pad plate 152 is related to the temperature change and the thermal expansion coefficient of the lower pad plate 152, and the horizontal displacement amount of the lower pad plate 152 can be calculated using the following relationship :

[0138] ;

[0139] wherein, represents the thermal expansion coefficient of the lower pad plate 152, represents the temperature of the lower pad plate 152.

[0140] S34: Calculate the main shaft inclination angle after the upper pad 151 and the lower pad 152 are deformed by heat;

[0141] the main shaft inclination angle after the upper pad 151 and the lower pad 152 are deformed by heat The following relationship can be used for calculation:

[0142] .

[0143] wherein, represents the thickness of the lower pad 152 at the lower fulcrum 1522 after deformed by heat, represents the thickness of the upper pad 151 at the upper fulcrum 1511 after deformed by heat.

[0144] S35: Solve the target temperature at which the lower pad 152 or the upper pad 151 is deformed based on the relationship that the difference between the main shaft inclination angle after the upper pad 151 and the lower pad 152 are deformed by heat and the initial main shaft inclination angle is equal to the compensation angle.

[0145] Since the difference between the main shaft inclination angle after the upper pad 151 and the lower pad 152 are deformed by heat and the initial main shaft inclination angle is equal to the compensation angle (denoted as ), the calculated in step S31 and step S34 are brought into this formula, wherein, in Δ θ y >0, the thermal expansion amount of the lower pad 152 needs to be controlled to increase the main shaft inclination angle, and the temperature control of the upper pad 151 can be omitted, at this time can be obtained by real-time monitoring, for example, by temperature sensor monitoring, because the grinding wheel 11 contacts the wafer 50 during the grinding process of the wafer thinning device, which generates grinding heat, and the grinding heat is conducted from the grinding wheel 11 to the main shaft 12, so that the temperature of the upper pad 151 in the working state is higher than the ambient temperature, that is , so even if the temperature control of the upper pad 151 is not performed, the temperature of the upper pad 151 is higher than the ambient temperature, thereby generating a temperature difference. In this case, the thermal expansion compensation angle model constructed in the embodiment can be used to solve the target temperature at which the lower pad 152 is deformed .

[0146] Similarly, when Δ θ y <0, the thermal expansion amount of the upper pad 151 needs to be controlled to reduce the main shaft inclination angle, and the temperature control of the lower pad 152 can be omitted, at this time can be obtained by real-time monitoring, and the temperature of the lower pad 152 in the working state is higher than the room temperature, that is Therefore, even if the lower pad 152 is not temperature controlled, the lower pad 152 will be higher than room temperature, thereby generating a temperature difference. In this case, the thermal expansion compensation angle model constructed in the embodiment can be used to solve the target temperature at which the upper pad 151 generates deformation .

[0147] It should be noted that, from the perspective of one-way thermal expansion, since the upper pad 151 and the lower pad 152 are both between the slider and the wing plate, the adjustment of the main shaft inclination angle can be realized by the deformation of the upper pad 151 and the deformation of the lower pad 152. By controlling the thermal deformation of the lower pad 152, the main shaft inclination angle can be increased, and conversely, by controlling the thermal deformation of the upper pad 151, the main shaft inclination angle can be decreased. Considering that it is easier to realize and has higher control accuracy to expand the adjustment pad by heating than to shrink the adjustment pad by cooling, the embodiment of the present application can use the thermal expansion characteristic to adjust the inclination angle in both cases of increasing and decreasing the main shaft inclination angle, and the adjustment of increasing or decreasing the main shaft 12 can be realized by separately controlling the temperature of a single pad, which can improve the adjustment efficiency and also improve the adjustment accuracy.

[0148] Non-limitingly, the embodiment uses the characteristics that it is easier to control and has higher accuracy to increase the temperature than to decrease the temperature, strategically selects the adjustment object, avoids adjustment lag or overshoot caused by factors such as unstable heat dissipation rate and environmental temperature interference during the cooling process, ensures the stability of the temperature reaching the target value, and further ensures the consistency of the deformation of the pad.

[0149] Non-limitingly, for a scenario in which the wafer thinning temperature is relatively sensitive, the heating expansion control of the lower pad 152 can cause heat conduction to the wafer 50, causing the grinding temperature to rise and thereby affecting the process result of the wafer 50. For the adjustment of the main shaft inclination angle of such wafer thinning, a joint adjustment mode of cooling or moderately heating the lower pad 152 while adjusting the upper pad 151 can be considered.

[0150] S4: Adjust the temperature of the adjustment pad between the main shaft seat 13 and the feed mechanism 14 to the target temperature, so that the adjustment pad generates corresponding deformation based on the temperature change to adjust the main shaft inclination angle.

[0151] After the target temperature is solved as described above, the temperature of the temperature adjusting component can be controlled to adjust the temperature of the adjustment pad to the target temperature, so that the adjustment pad deforms based on the change in temperature, and then the distance between the slider and the wing plate is adjusted, so that the main shaft inclination angle changes.

[0152] The embodiment utilizes the thermal expansion characteristics of the adjusting pad to adjust the inclination angle of the main shaft. When the inclination angle of the main shaft needs to be adjusted, the temperature of the adjusting pad is controlled to change, so that the adjusting pad deforms based on the temperature change, thereby adjusting the inclination angle of the main shaft. Since the thermal expansion coefficient of the adjusting pad is fixed, the deformation amount caused by heating is also fixed when the temperature change is determined. Therefore, the deformation amount of the adjusting pad required can be generated by accurately controlling the temperature change of the adjusting pad, so that the inclination angle of the main shaft can be finely adjusted.

[0153] Compared with the traditional mechanical adjustment, the application avoids the step change inherent in the mechanical adjustment, so that the inclination angle of the main shaft can be finely and stably adjusted, and the wear of the adjusting pad caused by the mechanical adjustment is avoided, and the grinding surface of the wafer is more accurately controlled. It should be noted that mechanical adjustment can cause wear of the adjusting component, thereby affecting the adjustment accuracy, and metal wear pollution can cause device contact short circuit and affect the yield of wafer processing.

[0154] Further, by automatic control of the temperature adjusting component, the uncertainty of manual operation is greatly reduced, the dependence of the adjustment result on the skill of the operator is significantly reduced, the adjustment operation error is reduced, and the grinding accuracy of the wafer is further improved.

[0155] The application can monitor the wafer surface in real time and adjust in time, realizes closed-loop control of the wafer grinding surface, eliminates the accumulation of wafer surface deviation caused by the delay problem of manual mechanical adjustment, and effectively improves the grinding accuracy of the wafer.

[0156] Since the traditional inclination angle adjustment of the main shaft depends on the hard contact of mechanical components, long-term and frequent adjustment can easily cause wear of the mechanical components, thereby increasing the frequency and cost of equipment maintenance. The embodiment adjusts the inclination angle of the main shaft indirectly by the thermal expansion deformation of the adjusting pad, without hard friction between mechanical components, greatly reduces the mechanical wear of the main shaft 12, the grinding wheel 11 and other core components, and prolongs the maintenance cycle of the wafer grinding equipment.

[0157] Reference Figure 10The schematic diagram of the grinding wheel grinding wafer provided by an embodiment of the present application is shown in the figure. When the grinding wheel 11 grinds the wafer 50, the arc formed by the contact part of the grinding wheel 11 and the wafer 50 is the grinding line OM, one end O of the grinding line is at the center of the wafer 50, and the other end M is at the edge of the wafer 50. The compensation angle of the spindle 12 can be divided into two dimensions of compensation angle, which are the first dimension compensation angle and the second dimension compensation angle, wherein the first dimension is the front and back direction, more specifically, it refers to the radius direction of the wafer 50 formed by the line connecting the two ends of the grinding line OM, and the second dimension is the left and right direction, more specifically, it refers to the direction perpendicular to the first dimension and extending horizontally. As known from the foregoing, the adjusting pad is arranged between the feed mechanism 14 and the spindle seat 13, so the spindle tilt angle adjusted based on the thermal deformation characteristics of the adjusting pad is the tilt angle of the spindle 12 in the first dimension. The tilt angle of the spindle 12 in the second dimension is not specifically limited in the present application.

[0158] In the present embodiment, the compensation angle of the spindle 12 based on the surface shape characteristics can specifically include:

[0159] The concave-convex degree δ 1 and the fullness degree δ 2 are input into the cambered surface model to obtain the output of the current first dimension tilt angle and the second dimension tilt angle of the spindle 12; that is, in the present embodiment, the spindle tilt angle includes the first dimension tilt angle and the second dimension tilt angle, and the cambered surface model is used to represent the corresponding relationship between the surface shape characteristics and the first dimension tilt angle and the second dimension tilt angle of the spindle 12.

[0160] The difference between the first dimension tilt angle and the first dimension target tilt angle is determined as the compensation angle.

[0161] Based on the cambered surface model, a quantitative compensation angle can be obtained, so that accurate adjustment and control of the tilt angle can be realized according to the compensation angle. For the compensation angle, the adjusting pad can be deformed by the temperature adjustment based on the present embodiment to realize the adjustment, which can realize ultra-fine adjustment and closed-loop control of the spindle tilt angle, improve the adjustment efficiency and accuracy of the spindle tilt angle, and because the temperature adjustment range is much lower than the Curie temperature of the spindle material, the elastic modulus of the spindle material and the stiffness of the spindle are not affected, thereby greatly improving the precision of wafer grinding.

[0162] In another embodiment of the present application, the difference between the first dimension tilt angle and the first dimension target tilt angle can be determined as the first dimension compensation angle, and the difference between the second dimension tilt angle and the second dimension target tilt angle can also be determined as the second dimension compensation angle. The present embodiment can further decouple the concave-convex degree δ 1 and the fullness degree δ 2 based on the adjustment relationship between the tilt angle and the surface shape characteristics to adjust the tilt angle of the spindle 12 in the first dimension and / or the tilt angle in the second dimension. The adjustment relationship between the tilt angle and the surface shape characteristics includes: the change of the first dimension tilt angle causes the concave-convex degree δ1 and fullness δ 2 both change, the second dimension tilt angle change makes the fullness δ 2 change, concavo-convex degree δ 1 no change. This embodiment first adjusts the tilt angle of the main shaft 12 in the first dimension based on the first dimension compensation angle, and then adjusts the tilt angle of the main shaft 12 in the second dimension based on the second dimension compensation angle. Specifically, it includes:

[0163] determine the concavo-convex degree δ 1 whether it is less than a first threshold, if so, execute the operation of determining the fullness δ 2 whether it is less than a second threshold, if not, adjust the tilt angle of the main shaft 12 in the first dimension based on the first dimension compensation angle, and then continue to execute the acquisition operation after continuing to grind for a preset time length; wherein adjusting the tilt angle of the main shaft 12 in the first dimension based on the first dimension compensation angle can use the method of the present application to adjust the tilt angle of the main shaft 12 in the first dimension by controlling the temperature change of the adjustment backing plate to cause the adjustment backing plate to generate corresponding deformation based on the temperature change.

[0164] determine the fullness δ 2 whether it is less than a second threshold, if so, trigger the execution of the acquisition operation after continuing to grind for a preset time length, if not, adjust the tilt angle of the main shaft 12 in the second dimension based on the second dimension compensation angle, and then trigger the execution of the acquisition operation after continuing to grind for a preset time length.

[0165] Wherein, the first dimension target tilt angle and the second dimension target tilt angle can be determined based on the target surface shape feature, that is, the first dimension target tilt angle and the second dimension target tilt angle are determined based on the target concavo-convex degree and the target fullness and the cambered surface model.

[0166] This embodiment decouples the concavo-convex degree δ 1 and fullness δ 2, so that the concavo-convex degree δ 1 and fullness δ 2 is no longer coupled, avoiding blind and inefficient adjustment of the tilt angle of the main shaft 12 in two dimensions, and through the concavo-convex degree δ 1 and fullness δ 2, accurate compensation angles can be obtained in two dimensions respectively, and the first dimension tilt angle is adjusted first. Since the first dimension tilt angle change makes the concavo-convex degree δ 1 and fullness δ 2 both change, therefore, when adjusting the first dimension tilt angle, the concavo-convex degree δ 1 and fullness δ 2 can be changed at the same time, through the adjustment of the first dimension tilt angle, at least the concavo-convex degree δ 1 meets the requirements, or makes the concavo-convex degree δ 1 and fullness δ2 meet the requirements, no need to perform the second dimension tilt angle adjustment, effectively improve the tilt angle adjustment efficiency, so as to ensure the wafer grinding efficiency. In addition, in the adjustment of the second dimension tilt angle, by adjusting the second dimension tilt angle to make the fullness δ 2 meet the requirements, while maintaining the already adjusted concave-convex degree δ 1 unaffected, thereby avoiding the repeated, inefficient adjustment of the concave-convex degree δ 1 and fullness δ 2 by the first dimension tilt angle, the second dimension tilt angle, the decoupling adjustment mode adjustment target is clear and reasonable, not only improves the efficiency of the tilt angle adjustment, and the adjustment process on the wafer's concave-convex degree δ 1 and fullness δ 2 control precision, and then improve the TTV precision of wafer grinding.

[0167] An embodiment of the present application provides a kind of construction method of cambered surface model, refer to Figure 10 , it includes the following steps:

[0168] First, in the coordinate system with the center O' of grinding wheel as origin, with the lower surface of grinding wheel as , with the extension direction of main shaft 12 as (Not shown) coordinate system, the grinding line OM Coordinate ( :

[0169]

[0170] Wherein, , Grinding wheel radius; Wafer radius;

[0171] Second, coordinate conversion is carried out, and the coordinate ( , ) of the grinding line OM after the main shaft 12 along the second dimension swing tilt angle x And along the first dimension swing tilt angle y Is obtained. z

[0172]

[0173] Wherein, Second dimension conversion matrix, First dimension conversion matrix.

[0174] ,

[0175] Third, the grinding line OM rotates around the center point O Of wafer​ the spherical coordinate representing the wafer surface grinding profile after grinding , .

[0176] wherein the circular arc rotation matrix ;

[0177] wafer center point O coordinate ;

[0178] Finally, the spherical surface can be constructed according to the spherical coordinate expression using software such as Matlab, and the obtained spherical surface is the wafer surface shape, that is, the spherical surface obtained after the grinding wheel grinds the wafer based on the grinding line for 360° is the wafer surface shape, and then the surface shape characteristics of the wafer can be obtained based on the spherical surface, thereby establishing the relationship between the surface shape characteristics and the inclination angles of the main shaft 12 in the first dimension and the second dimension.

[0179] In the present embodiment, the spherical surface model can be constructed in advance, and then the inclination angle of the current main shaft 12 along the second dimension and the inclination angle along the first dimension can be inversely solved based on the surface shape characteristics of the current wafer, so that the compensation angle can be obtained based on the inclination angle of the first dimension , which provides an accurate basis for the adjustment of the main shaft inclination angle, effectively improves the accuracy of the adjustment of the main shaft inclination angle, and thus improves the accuracy of the wafer grinding.

[0180] It has been verified that, by using the thinning method of the present application, the control accuracy of the main shaft inclination angle can reach 0.0001°, and the TTV accuracy of the ground wafer can reach less than 1 μm.

[0181] The present application realizes closed-loop control of the wafer grinding surface shape characteristics, eliminates the delay problem of artificial mechanical adjustment and the error caused by artificial operation, effectively improves the overall efficiency of wafer grinding, and improves the TTV accuracy of wafer grinding.

[0182] The present application utilizes the thermal expansion and contraction property of the adjustment pad, accurately controls the temperature change of the adjustment pad, makes the adjustment pad produce corresponding deformation, thereby realizing ultra-fine adjustment of the main shaft inclination angle, effectively improving the accuracy of the adjustment of the main shaft inclination angle, and effectively controlling the surface shape characteristics of wafer grinding, improving the TTV accuracy of wafer grinding, thereby providing technical support for ultra-high density semiconductor stacking process. Compared with the traditional mechanical adjustment method, the present application avoids the adjustment error and equipment failure caused by the wear and loosening of mechanical parts, improves the stability and reliability of the equipment.

[0183] In a non-limiting embodiment, this application also provides a method for wafer grinding, comprising: determining a wafer surface shape; inputting the wafer surface shape into an arc surface model to determine a grinding parameter adjustment method; the grinding parameter adjustment method includes: the proportion and adjustment amount of different adjustment methods; the different adjustment methods include: adjusting the temperature of the lower pad 152, adjusting the temperature of the upper pad 151, and adjusting the position of the worktable 30.

[0184] Reference Figure 11 The diagram shown is a structural block diagram of a thinning device provided in one embodiment of this application, including: a feature acquisition unit 110, a compensation angle determination unit 111, a target temperature determination unit 112, and a tilt angle adjustment unit 113.

[0185] The feature acquisition unit 110 is used to acquire the surface features of the wafer during the wafer grinding process of the wafer thinning equipment;

[0186] The compensation angle determination unit 111 is used to determine the compensation angle of the spindle 12 based on the surface features. The spindle 12 is connected to the grinding wheel 11 for grinding the wafer to drive the grinding wheel 11 to rotate, and the spindle 12 is located in the spindle seat 13.

[0187] The target temperature determination unit 112 is used to input the compensation angle into the thermal expansion compensation angle model to obtain the output target temperature.

[0188] The tilt angle adjustment unit 113 is used to adjust the temperature of the adjustment pad between the spindle seat 13 and the feed mechanism 14 to the target temperature, so that the adjustment pad will deform accordingly based on the temperature change, thereby adjusting the spindle tilt angle.

[0189] 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.

[0190] See Figure 12 , Figure 12 This is a schematic block diagram of an electronic device provided according to an embodiment of this application. Figure 12 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 each unit in the above-described device embodiments, for example... Figure 11 The functions of the feature acquisition unit 110, compensation angle determination unit 111, target temperature determination unit 112, and tilt angle adjustment unit 113 are shown.

[0191] It should be understood that, in the embodiments of the present application, the processor 601 can be a central processing unit, and can also be other general-purpose processors, digital signal processors, application-specific integrated circuits, etc.

[0192] The input device 602 can include a touchpad, etc., and the output device 603 can include a display, a speaker, etc.

[0193] The memory 604 can include a read-only memory or a random access memory, and provide instructions and data for the processor 601, and a part of the memory 604 can also include a non-volatile random access memory.

[0194] In specific implementations, the processor 601, the input device 602, and the output device 603 described in the embodiments of the present application can execute the implementation manners described in the thinning method provided by the embodiments of the present application, and can also execute the implementation manners of the electronic device described in the embodiments of the present application, which will not be described here.

[0195] In another embodiment of the present application, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program. The computer program includes program instructions, and the program instructions are executed by a processor to implement all or part of the processes in the above-mentioned embodiment method, or the related hardware can be completed by the computer program. The computer readable medium can include any entity or device capable of carrying computer program codes, a U disk, a mobile hard disk, a computer memory, a read-only memory, etc.

[0196] 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 a 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, a smart memory card, etc.

[0197] The embodiments of the present application provide a computer program product, which includes computer executable instructions or a computer program. The computer executable instructions or the computer program are stored in a computer readable storage medium. A processor of an electronic device reads the computer executable instructions from the computer readable storage medium. The processor executes the computer executable instructions, so that the electronic device executes the implementation manners described in the thinning method provided by the embodiments of the present application.

[0198] It should be noted that, according to the needs of implementation, each component / step described in the embodiments of the present application can be split into more components / steps, or two or more components / steps or part of the operations of the components / steps can be combined into a new component / step, to achieve the purpose of the embodiments of the present application.

[0199] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A thinning method characterized by, The method comprises: acquiring a surface profile of a wafer during grinding of the wafer by a wafer thinning apparatus; the surface profile comprises concave-convex degree and fullness degree; determining a compensation angle of a spindle based on the surface profile, the spindle being connected with a grinding wheel of the wafer thinning apparatus to drive the grinding wheel to rotate, and the spindle being arranged in a spindle holder; decoupling the concave-convex degree and the fullness degree based on an adjustment relationship between an inclination angle of the spindle and the surface profile, to adjust the inclination angle of the spindle, the adjustment relationship between the inclination angle and the surface profile comprising: a first dimension inclination angle change causing both the concave-convex degree and the fullness degree to change, and a second dimension inclination angle change causing the fullness degree to change and the concave-convex degree to remain unchanged; wherein, the first dimension inclination angle is adjusted based on a first dimension compensation angle first, so that at least the concave-convex degree meets the requirement, and then the second dimension inclination angle is adjusted based on a second dimension compensation angle, so that the fullness degree meets the requirement while the concave-convex degree that has been adjusted remains unchanged; the adjustment of the first dimension inclination angle based on the first dimension compensation angle comprises: inputting the first dimension compensation angle into a thermal expansion compensation angle model to obtain a target temperature as an output; adjusting a temperature of an adjustment pad plate between the spindle holder and a feed mechanism to the target temperature, so that the adjustment pad plate generates a corresponding deformation based on the temperature change to adjust the inclination angle of the spindle in the first dimension.

2. The thinning method according to claim 1, characterized by, the adjustment pad plate comprises an upper pad plate and a lower pad plate inserted downward and upward between the spindle holder and the feed mechanism respectively, and the thermal expansion compensation angle model is constructed based on a horizontal displacement amount of the lower pad plate at a lower fulcrum after thermal deformation of the lower pad plate, to calculate a spindle inclination angle after deformation of the lower pad plate, and based on an equal amount relationship that a difference between the spindle inclination angle after deformation of the lower pad plate and an initial spindle inclination angle is equal to the first dimension compensation angle, to solve a target temperature at which the lower pad plate generates the deformation.

3. The thinning method of claim 1, wherein the adjustment pad plate comprises an upper pad plate and a lower pad plate inserted downward and upward between the spindle holder and the feed mechanism respectively, and the thermal expansion compensation angle model is constructed based on horizontal displacement amounts of the upper pad plate and the lower pad plate at upper and lower fulcrums respectively after thermal deformation of the upper pad plate and the lower pad plate, to calculate a spindle inclination angle after thermal deformation of the upper pad plate and the lower pad plate, and based on an equal amount relationship that a difference between the spindle inclination angle after thermal deformation of the upper pad plate and the lower pad plate and an initial spindle inclination angle is equal to the first dimension compensation angle, to solve a target temperature at which the lower pad plate or the upper pad plate generates the deformation.

4. The thinning method according to claim 3, characterized by, the thermal expansion compensation angle model is constructed based on: calculating the horizontal displacement amount of the upper pad plate at the upper fulcrum after thermal deformation of the upper pad plate based on a thermal expansion coefficient of the upper pad plate, a temperature change, and a thickness of the upper pad plate at the upper fulcrum; calculating the horizontal displacement amount of the lower pad plate at the lower fulcrum after thermal deformation of the lower pad plate based on a thermal expansion coefficient of the lower pad plate, a temperature change, and a thickness of the lower pad plate at the lower fulcrum; calculating the spindle inclination angle after thermal deformation of the lower pad plate or the upper pad plate based on a difference between the thickness of the lower pad plate at the lower fulcrum after thermal deformation and the thickness of the upper pad plate at the upper fulcrum after thermal deformation, an initial distance between the upper fulcrum and a top surface of the lower pad plate, and a length of the lower pad plate along a direction of the spindle.

5. The thinning method according to claim 3, wherein the thinning method comprises: when the first dimension compensation angle is greater than 0°, solving the target temperature at which the lower pad plate generates the deformation by the thermal expansion compensation angle model, and adjusting the temperature of the lower pad plate to the target temperature; When the first-dimension compensation angle is less than 0°, a target temperature at which the upper pad generates the deformation is solved by the thermal expansion compensation angle model, and the temperature of the upper pad is adjusted to the target temperature.

6. The thinning method according to any one of claims 1 to 5, characterized by, The compensation angle of the main shaft based on the surface shape feature comprises: inputting the surface shape feature into a ruled surface model to obtain an output current main shaft inclination angle; the ruled surface model is constructed based on a grinding line formed when the grinding wheel contacts the wafer, and the ruled surface model is used to represent the corresponding relationship between the surface shape feature and the main shaft inclination angle; a difference between the current main shaft inclination angle and a target inclination angle is determined as the compensation angle.

7. The thinning method according to claim 6, characterized by, The output current main shaft inclination angle comprises a first-dimension inclination angle and a second-dimension inclination angle; the contact part of the grinding wheel and the wafer forms an arc-shaped grinding line, one end of the grinding line is at the center of the wafer, and the other end is at the edge of the wafer; the first dimension is the wafer radius direction in which the two ends of the grinding line are located; and the second dimension is a horizontal direction perpendicular to the first dimension.

8. Wafer thinning apparatus characterized by, Comprise: a grinding device, an adsorption platform, and a temperature control unit; The adsorption platform is used to carry and rotate the wafer; The grinding device is arranged above the adsorption platform and comprises a main shaft for rotating the grinding wheel; The grinding device further comprises a main shaft seat, a feeding mechanism, and an adjusting pad; the main shaft is coaxially arranged in the main shaft seat; the main shaft seat is connected to the feeding mechanism; the adjusting pad is at least partially inserted between the feeding mechanism and the main shaft seat; and the adjusting pad is provided with a temperature adjusting component; The temperature control unit is electrically connected with the temperature adjusting component and is used to execute the method of any one of claims 1 to 7 to adjust the main shaft inclination angle.

9. The wafer thinning apparatus according to claim 8, wherein The main shaft seat comprises a tubular main body and wing plates extending outwardly and parallelly on the left and right sides of the main body; the feeding mechanism comprises a slide rail arranged in a vertical direction and a slide block moving vertically along the slide rail; The adjusting pad is at least partially inserted between the slide block and the wing plates.

10. The wafer thinning apparatus according to claim 9, wherein The adjusting pad comprises an upper pad and a lower pad, which are respectively inserted downwardly and upwardly between the slide block and the wing plates.

11. The wafer thinning apparatus according to claim 10, wherein The temperature adjusting component is arranged at least in one of the upper pad and the lower pad.

12. The wafer thinning apparatus according to any one of claims 8 to 11, wherein The temperature adjusting component comprises: a temperature sensor and at least one temperature control actuator; the temperature sensor and the temperature control actuator are electrically connected with the temperature control unit; and the temperature sensor is used to monitor the temperature of the adjusting pad.

13. The wafer thinning apparatus of claim 10, wherein, The thermal expansion compensation angle model is constructed as: a horizontal displacement of the lower pad at a lower fulcrum after being deformed by heat is used to calculate the main shaft inclination angle after the deformation of the lower pad; a difference between the main shaft inclination angle after the deformation of the lower pad and an initial main shaft inclination angle is equal to the first-dimension compensation angle in an equivalent relationship, and a target temperature at which the lower pad generates the deformation is solved; or Based on the horizontal displacement amounts of the upper pad and the lower pad after being deformed by heat at the upper fulcrum and the lower fulcrum respectively, the main shaft inclination angle after the upper pad and the lower pad are deformed by heat is calculated, and based on the difference between the main shaft inclination angle after the upper pad and the lower pad are deformed by heat and the initial main shaft inclination angle being equal to the first dimension compensation angle, the target temperature at which the lower pad or the upper pad generates the deformation is solved.

Images