Wafer double-side thinning method and system

Abstract

The application relates to the field of wafer processing, in particular to a wafer double-face thinning method and system, which comprises the following steps: acquiring wafer surface topography parameters and grinding wheel wear data of a previous wafer; wherein the wafer surface topography parameters comprise a PV curve and a BOW value; establishing a second compensation function model of the wafer surface topography parameters and the grinding wheel wear data about an inclination compensation amount W; and adjusting the inclination compensation amount W of the grinding wheel based on the second compensation function model to center the wafer. The application establishes a functional relationship between the wafer surface topography parameters and the grinding wheel wear data about the inclination compensation based on the wafer surface topography parameters and the grinding wheel wear data of the previous wafer, and the functional relationship is applied to the next wafer processing to center the wafer.

Description

Technical Field

[0001] This application relates to the field of wafer fabrication, and in particular to a method and system for double-sided wafer thinning. Background Technology

[0002] In the double-sided thinning equipment, the wafer is placed vertically on a ring-shaped carrier, which is positioned between two substrates. Fluid is supplied to both sides of the wafer through the substrates to balance the wafer pressure, causing the wafer and the carrier to rotate together. At the same time, grinding wheels located on both sides of the wafer grind the two surfaces of the wafer. During the grinding process, the two grinding wheels are fed axially until the wafer reaches the thickness required by the process.

[0003] In the existing technology, grinding wheels on both sides of the wafer act on the wafer. As the wafer continues to be ground, it becomes thinner, forming a large gap between the wafer and the substrate. This makes the wafer prone to tilting, thus affecting the quality of the wafer thinning process.

[0004] Therefore, the technical problem with the existing technology is that wafer tilting during the thinning process affects the processing quality. Summary of the Invention

[0005] This application provides a wafer double-sided thinning method and system that improves wafer alignment by controlling liquid compensation and / or tilt angle compensation.

[0006] On the one hand, the wafer double-sided thinning method provided in this application adopts the following technical solution:

[0007] A wafer double-sided thinning method is applied to a double-sided thinning apparatus, the double-sided thinning apparatus comprising: a substrate assembly, the substrate assembly including substrates, the substrates having two sets, the two sets of substrates being arranged opposite each other; a support assembly, the support assembly including a carrier ring and a support member, the carrier ring being used to support the wafer, the carrier ring being disposed between the two sets of substrates, and the support member being used to support the carrier ring, so that the carrier ring and the wafer can be vertically arranged between the two sets of substrates; and a grinding wheel assembly, the grinding wheel assembly including grinding wheels, the grinding wheels having two sets, the two sets of grinding wheels being respectively disposed on both sides of the carrier ring, so that the grinding wheels can move along the axial direction. For grinding wafers; and a driving assembly for driving the carrier ring and wafer to rotate; wherein, the substrate is provided with a liquid supply port for supplying liquid to the wafer to support the wafer; the substrate is provided with a distance sensor for detecting wafer offset; the method includes: acquiring the pressure change ΔP between the substrate and the wafer, the wafer position offset Δx, and the wafer position offset rate; establishing a first compensation function model of the pressure change ΔP and the wafer position offset Δx between the substrate and the wafer with respect to the liquid compensation amount Q; and adjusting the liquid compensation amount Q of the liquid supply port based on the first compensation function model to center the wafer.

[0008] Preferably, the first compensation function model is:

[0009]

[0010] Among them, K r It is the proportionality constant of Δx;

[0011] K p This is a control coefficient used to adjust pressure changes;

[0012] K x These are control coefficients used to adjust wafer position offset;

[0013] K dx This is a control coefficient used to adjust the wafer position offset rate.

[0014] Preferably, the grinding wheel is rotatable both vertically and horizontally, allowing for angle adjustment relative to the wafer. The method further includes: acquiring surface morphology parameters of the previous wafer and grinding wheel wear data; wherein the wafer surface morphology parameters include PV curves and BOW values; establishing a second compensation function model of the previous wafer surface morphology parameters and grinding wheel wear data with respect to the tilt angle compensation amount W; and adjusting the tilt angle compensation amount W of the grinding wheel based on the second compensation function model to center the wafer.

[0015] Preferably, the second compensation function model is:

[0016]

[0017] Among them, PV rms K is the root mean square of the peak and trough values ​​in the PV curve. PV For PV rms Control coefficients;

[0018] △PV1 is the maximum amplitude of the Center-mark in the PV curve; K1 is the control coefficient for △PV1;

[0019] △PV2 is the maximum amplitude of the B-ring curve in the PV curve; K2 is the control coefficient for △PV2;

[0020] ΔB is the BOW value; K r ' is the proportionality coefficient of ΔB; K B This is the control coefficient for ΔB;

[0021] △X represents the wear of the grinding wheel; K X This is the control coefficient for △X.

[0022] Preferably, the method further includes: acquiring liquid compensation amount Q, tilt angle compensation amount W, and grinding current data; establishing a third compensation function model of liquid compensation amount Q, tilt angle compensation amount W, and grinding current data with respect to comprehensive compensation amount Y; and adjusting the liquid compensation amount Q of the liquid supply port and the tilt angle compensation amount W of the grinding wheel based on the third compensation function model to center the wafer.

[0023] Preferably, the third compensation function model is:

[0024]

[0025] Among them, K q This is the proportionality coefficient for the liquid compensation amount;

[0026] K w This is the proportional coefficient for the tilt compensation amount;

[0027] K i This is the scaling factor for the current data during the grinding stage;

[0028] It is a weighted average of the difference between the reference current measured during the grinding stage and the voltage-side current data.

[0029] Preferably, a preset value θ is set, and the liquid compensation amount Q is calculated. It is then determined that: if the liquid compensation amount Q < the preset value θ, the liquid compensation amount Q of the liquid supply port is adjusted based on the first compensation function model to center the wafer; if the liquid compensation amount Q > the preset value θ, the liquid compensation amount Q of the liquid supply port and the tilt angle compensation amount W of the grinding wheel are adjusted based on the third compensation function model to center the wafer.

[0030] On the other hand, the wafer double-sided thinning system provided in this application adopts the following technical solution:

[0031] A wafer double-sided thinning system is applied to a double-sided thinning apparatus, the double-sided thinning apparatus comprising: a substrate assembly, the substrate assembly including substrates, the substrates having two sets, the two sets of substrates being arranged opposite each other; a carrier assembly, the carrier assembly including a carrier ring and a support member, the carrier ring being used to carry the wafer, the carrier ring being disposed between the two sets of substrates, and the support member being used to support the carrier ring, so that the carrier ring and the wafer can be vertically arranged between the two sets of substrates; a grinding wheel assembly, the grinding wheel assembly including grinding wheels, the grinding wheels having two sets, the two sets of grinding wheels being respectively disposed on both sides of the carrier ring, so that the grinding wheels can act on the wafer axially to perform grinding; and a driving assembly, the driving assembly being used to drive the carrier ring. The system includes: a substrate for supplying liquid to the wafer to support it; a distance sensor for detecting wafer offset; and a first parameter acquisition module for acquiring the pressure change ΔP, wafer position offset Δx, and wafer position offset rate between the substrate and the wafer; a first function establishment module for establishing a first compensation function model of the pressure change ΔP and wafer position offset Δx between the substrate and the wafer with respect to the liquid compensation amount Q; and a first adjustment confirmation module for confirming the liquid compensation amount Q of the supply port based on the first compensation function model.

[0032] Preferably, the grinding wheel is rotatable both vertically and horizontally, allowing for angle adjustment relative to the wafer. The system further includes: a second parameter acquisition module for acquiring surface morphology parameters of the previous wafer and grinding wheel wear data; wherein the wafer surface morphology parameters include PV curves and BOW values; a second function establishment module for establishing a second compensation function model of the previous wafer surface morphology parameters and grinding wheel wear data with respect to the tilt angle compensation amount W; and a second adjustment confirmation module for confirming the tilt angle compensation amount W of the grinding wheel based on the second compensation function model.

[0033] Preferably, the system further includes: a third parameter acquisition module, which is used to acquire liquid compensation amount Q, tilt angle compensation amount W, and grinding current data; a third function establishment module, which is used to establish a third compensation function model of liquid compensation amount Q, tilt angle compensation amount W, and grinding current data with respect to comprehensive compensation amount Y; and a third adjustment confirmation module, which is used to confirm the liquid compensation amount Q of the liquid supply port and the tilt angle compensation amount W of the grinding wheel based on the third compensation function model.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] Based on the surface morphology parameters of the previous wafer and the grinding wheel wear data, this application establishes a functional relationship between the surface morphology parameters of the wafer and the grinding wheel wear data with respect to tilt angle compensation, which is then applied to the next wafer processing to achieve wafer alignment. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the double-sided thinning device described in this application;

[0037] Figure 2 This is a schematic diagram of the ranging sensor on the substrate of the double-sided thinning device described in this application;

[0038] Figure 3 This is a schematic diagram of the liquid supply port on the substrate of the double-sided thinning device described in this application;

[0039] Figure 4 This is a schematic diagram of the first embodiment of the double-sided thinning method described in this application;

[0040] Figure 5 This is a second schematic diagram of the double-sided thinning method described in this application;

[0041] Figure 6 This is a schematic diagram of the PV curve in the double-sided thinning method described in this application;

[0042] Figure 7 This is a third schematic diagram of the double-sided thinning method described in this application.

[0043] Explanation of reference numerals in the attached drawings: 100, substrate assembly; 110, substrate; 120, liquid supply port; 130, distance sensor; 200, carrier assembly; 210, carrier ring; 220, support member; 300, grinding wheel assembly; 310, grinding wheel; 400, wafer. Detailed Implementation

[0044] The serial numbers assigned to components in this document, such as "first" and "second," are used solely to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). It should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are used solely for the convenience of describing this application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] This application provides a method and system for double-sided thinning of a 400 wafer, which improves the centering effect of the 400 wafer by controlling liquid compensation and tilt angle compensation.

[0047] To better understand the above technical solutions, a detailed description of the technical solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit the scope of this application.

[0048] This application provides a method for double-sided thinning of a 400mm wafer, applied to a double-sided thinning apparatus, such as... Figures 1-3 As shown, the double-sided thinning apparatus includes: a substrate assembly 100, a support assembly 200, a grinding wheel assembly 300, and a drive assembly (not shown). The substrate assembly 100 includes two sets of substrates 110, which are arranged opposite each other. The support assembly 200 includes a carrier ring 210 and a support member 220. The carrier ring 210 is used to support the wafer 400 and is disposed between the two sets of substrates 110. The support member 220 is used to support the carrier ring 210. 10, so that the carrier ring 210 and the wafer 400 can be vertically arranged between the two sets of substrates 110, and the support member 220 can be rotated so that the carrier ring 210 can rotate while being supported by the support member 220; the grinding wheel assembly 300 includes grinding wheels 310, which have two sets, and the two sets of grinding wheels 310 are respectively arranged on both sides of the carrier ring 210 so that the grinding wheels 310 can act on the wafer 400 along the axial direction to perform grinding; the driving assembly is used to drive the carrier ring 210 and the wafer 400 to rotate.

[0049] It should be noted that the substrate assembly 100, the carrier assembly 200, the grinding wheel assembly 300, and the drive assembly are all existing double-sided thinning structures, and will not be described in detail in this embodiment.

[0050] Among them, such as Figure 2 , 3As shown, a liquid supply port 120 is provided on the substrate 110 for supplying liquid to the wafer 400 to support the wafer 400; a distance sensor 130 is provided on the substrate 110 for detecting the offset of the wafer 400; specifically, the liquid supply port 120 is used to connect to an external liquid supply source, such as a water tank, and a water pump supplies liquid from the water tank to the liquid supply port 120 so that the liquid flows out from the liquid supply port 120 to support the wafer 400; in one embodiment, multiple liquid supply ports 120 can be provided on each substrate 110; the distance sensor 130 can be a pneumatic gauge, and a pneumatic gauge detection port is provided on the substrate 110 to detect the position of the wafer 400; in one embodiment, multiple pneumatic gauges (distance sensors) can be provided on each substrate 110.

[0051] Based on the aforementioned double-sided thinning equipment, this embodiment proposes the following method: (e.g., ...) Figure 4 As shown, S1.1: Obtain the pressure change ΔP, wafer position offset Δx, and wafer position offset rate between the substrate 110 and the wafer 400; S1.2: Establish a first compensation function model of the pressure change ΔP and wafer position offset Δx between the substrate 110 and the wafer 400 with respect to the liquid compensation amount Q; S1.3: Adjust the liquid compensation amount Q of the liquid supply port 120 based on the first compensation function model to center the wafer 400.

[0052] In other words, the fluid compensation amount Q is calculated based on the pressure change ΔP and the wafer position offset Δx. Q is related to ΔP and Δx, and by simultaneously solving the correlation functions, the parameters required to achieve dynamic fluid compensation can be calculated. It should be noted that real-time monitoring of changes in ΔP and Δx, and dynamic adjustment of fluid flow rate and pressure based on the calculation results, are necessary to achieve accurate fluid compensation.

[0053] The first compensation function model is:

[0054]

[0055] Among them, K r It is the proportionality constant of Δx;

[0056] K p This is a control coefficient used to adjust pressure changes;

[0057] K x These are control coefficients used to adjust wafer position offset;

[0058] K dx This is a control coefficient used to adjust the wafer position offset rate.

[0059] In one embodiment, a pneumatic gauge monitors the distance between wafer 400 and substrate 110 in real time, with three monitoring points on each side, resulting in a total of six raw data points. The wafer position offset Δx at each pneumatic gauge monitoring port is recorded.ij (i=1, 2, 3, j=1, 2, 3)=x 基ij -x 加ij j1, j2, and j3 correspond to the values ​​at the tool receiving position, the start of the fine grinding stage, and the start of the finishing grinding stage, respectively.

[0060] By fitting the above 9 data points to a curve, the overall wafer 400 skew state and wafer position offset Δx were obtained; Δx was sampled every 1 second. ij The wafer position offset rate is obtained by fitting the values ​​from the grinding stage. Record the pressure P for each manual adjustment. ij (i = 1-8 corresponds to 8 liquid supply ports 120, j = 1, 2, corresponding to two substrates 110), the weighted average of each group of data is obtained. (Ps is the standard value of 0.2 MPa).

[0061] The above Δx, The ΔP value is recorded in the first compensation function model. In the middle, at the same time K r Use 1 / 2 as a trial value to verify the deviation between subsequent data and the model, and continuously try different values ​​for K. r After obtaining a more accurate value, the steepest gradient is confirmed for K. p K x K dx With the control coefficients set, the first compensation function model is now complete.

[0062] Data fitting:

[0063] Offset data is directly read and calculated through each pneumatic gauge monitoring port; for data from three monitoring points in the same stage (e.g., the tool engagement stage), a cubic polynomial fitting is used to obtain the overall offset function Δx. j (t), where t is time. For example, the offset function during the tool engagement stage can be expressed as:

[0064] Δx1(t)=a1t 3 +b1t 2 +c1t+d1

[0065] The coefficients a1, b1, c1, and d1 are determined by least squares fitting.

[0066] Offset rate calculation:

[0067] The rate of change of the offset is obtained by taking the derivative of the fitting function with respect to time:

[0068]

[0069] For example, in the fine grinding stage (j=2), if the fitting result is Δx2(t) = 0.02t 3 -0.5t 2 +3t, then the speed is:

[0070]

[0071] Pressure deviation calculation:

[0072] In one embodiment, pressure data P is collected from eight water support ports. ij (i = 1-8 correspond to 8 liquid supply ports 120, j = 1, 2, corresponding to two substrates 110), calculate the weighted average:

[0073]

[0074] Where the weight w i The weighting is set according to the symmetry of the support locations (e.g., the weight of the central support location is 0.3, and the weight of the edge support location is 0.1); the pressure deviation is:

[0075]

[0076] The first compensation function model is:

[0077]

[0078] Initial trial value: Set K r =0.5, other coefficients K p =K x =K dx =1.

[0079] Gradient descent optimization:

[0080] Define the loss function: L = ∑(Q) 实际 -Q 模型 ) 2 Calculate the partial derivatives of the loss with respect to each coefficient: Similarly, calculate

[0081] Update coefficients: Where α is the learning rate (e.g., α = 0.01); iterate until the loss function converges, such as L < 10. -4 .

[0082] For example:

[0083] Assume that a certain monitoring data is ΔP = 0.05 MPa and Δx = 0.8 μm. The model output with initial coefficients is: Q 模型 = 1 × 0.05 + 1 × 0.8 0.5+1×0.2=1.144;

[0084] If the actual compensation amount Q 实际 If the value is 1.5, then the loss is L = (1.5 - 1.144). 2 =0.127; by iteratively adjusting the coefficients through gradient descent, K is finally obtained after optimization. p =2.1,K x =1.6,K dx =0.5.

[0085] However, due to limitations in the mechanical structure, when the Q adjustment is small (Q≤θ), liquid compensation can meet the wafer 400 attitude adjustment requirements; but when Q≥θ, it is necessary to combine it with the tilt compensation of the grinding wheel 310.

[0086] By combining the Wrap3D image (to view the simulated overall morphology of wafer 400), PV curve and values ​​(to view the degree and amplitude of unevenness in the Center-mark and B-ring areas, the uniformity and values ​​of the overall PV curve), and BOW curve and values ​​(to view how wafer 400 bends at the overall level) obtained on the testing equipment, and by comprehensively combining the current monitoring data on both sides of the grinding wheel 310 during each grinding cycle and the tooth consumption data of the grinding wheel 310, the minute horizontal angle of the two sides of the grinding wheel 310 and the micron-level left and right movement of the grinding wheel 310 tool engagement position in the axial direction can be adjusted to achieve precise adjustment of the upright state of wafer 400 during grinding and the degree of wafer 400 warpage, thereby controlling the wafer 400 parameters.

[0087] Furthermore, the grinding wheel 310 can rotate vertically and horizontally, allowing the grinding wheel 310 to be angled relative to the wafer 400; in other words, the grinding wheel 310 is adjustable relative to the wafer 400, so that the wafer 400 can be aligned and centered through the adjustment of the grinding wheel 310's position. Figure 5 As shown, the method further includes: S2.1: acquiring the surface morphology parameters of the previous wafer and the grinding wheel wear data; wherein, the wafer surface morphology parameters include the PV curve and BOW value; S2.2: establishing a second compensation function model of the surface morphology parameters of the previous wafer and the grinding wheel wear data with respect to the tilt angle compensation amount W; S2.3: adjusting the tilt angle compensation amount W of the grinding wheel 310 based on the second compensation function model to center the wafer 400.

[0088] The second compensation function model is:

[0089]

[0090] Among them, PV rms It is the root mean square of the peak and valley values ​​in the PV curve, reflecting the microscopic unevenness of the wafer 400 surface; K PVThese are their corresponding control coefficients; ΔPV1 is the maximum amplitude of the Center-mark in PV, and ΔPV2 is the maximum amplitude of the B-ring in PV; K1 and K2 are their corresponding control coefficients; ΔB is the BOW value (including positive and negative), K r ' is the coefficient ratio related to ΔB, K B It is its corresponding control coefficient; ΔX is the wear amount of the grinding wheel in this grinding cycle, K X It is its corresponding control coefficient;

[0091] like Figure 6 As shown in the PV curve graph, the PV values ​​corresponding to every 25 points from the horizontal axis 25 to 250 in the first to fourth curves are collected. i (1≤i≤11), the root mean square of these data is used to obtain PV rms .

[0092] ΔPV1 is obtained by selecting the maximum / minimum value within the range of 100-200 on the horizontal axis, and ΔPV2 is obtained by selecting the maximum / minimum value within the ranges of 0-50 and 250-300 on the horizontal axis.

[0093] The above PV for each grinding wheel rms ΔPV1, ΔPV2, and the aforementioned ΔB and ΔX data are imported into the W model, K r 'Start with 1.5 as a trial value, and temporarily set the proportions of the other coefficients to 1. Verify the deviation between the subsequent data and the model, and continuously test K.' r After obtaining a more accurate value, the steepest gradient is confirmed for K. PV K1, K2, K B K X With the control coefficients set, the second compensation function model is now complete.

[0094] Specific model parameter determination process:

[0095] The PV curve reflects the peak-valley height difference at different locations on the wafer 400 surface during grinding, and is used to evaluate surface flatness; the maximum peak and valley values ​​are obtained to form the PV curve.

[0096] The root mean square (PVrms) value of the PV curve refers to the root mean square value of the PV curve over a specific region, used to quantify the surface micro-irregularity. Within the x-axis range of 25 to 250 of the PV curve, 11 points are taken at intervals of 25 (coordinates 25, 50, 75, ..., 250); the PV value (peak-to-valley difference) at each point is recorded and denoted as PV1, PV2, ..., PV... 11 ,but

[0097]

[0098] Example: If the PV values ​​of the 11 points are 2, 3, 4, ..., 12 μm, then:

[0099]

[0100] Regional peak-to-valley difference (△PV1 and △PV2):

[0101] △PV1: Within the range of 100-200 on the horizontal axis, take the difference between the maximum and minimum PV values.

[0102] ΔPV1=PV max (100-200)-PV min (100-200) Example: If the maximum PV value in this area is 10μm and the minimum is 4μm, then △PV1=6um.

[0103] △PV2: Within the horizontal coordinate ranges of 0-50 and 250-300, take the difference between the maximum and minimum PV values ​​respectively, and then calculate them together:

[0104] ΔPV2=max(PV max (0-50), PV max (250-300))-min(PV min (0-50), PV min (250-300)

[0105] Example: If the maximum value of PV in the range of 0-50 is 8 μm and the minimum value is 2 μm; and the maximum value of PV in the range of 250-300 is 7 μm and the minimum value is 3 μm, then: △PV2=max(8,7)-min(2,3)=8-2=6μm.

[0106] The BOW value (wafer 400 curvature) refers to the overall curvature of wafer 400 analyzed by Wrap3D image. The BOW value is the height difference between the center and the edge of wafer 400. If the Wrap3D image shows that the center concavity depth is +5um and the edge warping is -3um, then: ΔB=5-(-3)=8μm;

[0107] The grinding wheel wear (ΔX) refers to the reduction in thickness of the grinding wheel 310 during the grinding process, which is monitored in real time by a tooth profile sensor. If the thickness of the grinding wheel 310 decreases by 0.1 mm after a certain grinding cycle, then:

[0108] The second compensation function model is:

[0109]

[0110] Setting K r =1.5, the remaining coefficients K PV=1, K1=1, K2=1, K B =1,K X =1;

[0111] Gradient descent optimization:

[0112] Define the loss function:

[0113] L=∑(W 实际 -W 模型 ) 2

[0114] Calculate partial derivatives and update coefficients:

[0115] For example, if PV rms If the term is the maximum value, then update K. PV : Where β is the learning rate, such as β = 0.001.

[0116] The model comprehensively reflects the causes of wafer 400 orientation anomalies by using data from three dimensions: PV curve, BOW curvature, and grinding wheel wear. The max function is used to automatically select the parameter with the greatest impact on the current state, avoiding the limitations of a single factor. The exponential term of BOW and the square root term of grinding wheel wear enhance the model's adaptability to complex processes.

[0117] When the fluid compensation reaches its limit value θ, a further grinding wheel 310 tilt angle compensation amount W is introduced. The adjustment of W is based on the micro-unevenness (rms PV) of the wafer 400 surface, the unevenness of the center-mark and B-ring regions (PV1 and PV2), the uniformity and value of the overall PV curve, the BOW value, and the grinding wheel wear amount ΔX. By constructing a functional model of W and collecting relevant data, the optimal grinding wheel 310 tilt angle compensation amount can be calculated.

[0118] Therefore, as Figure 7 As shown, the method also includes: S3.1: acquiring liquid compensation amount Q, tilt angle compensation amount W, and grinding current data; S3.2: establishing a third compensation function model of liquid compensation amount Q, tilt angle compensation amount W, and grinding current data with respect to comprehensive compensation amount Y; S3.3: adjusting the liquid compensation amount Q of liquid supply port 120 and the tilt angle compensation amount W of grinding wheel 310 based on the third compensation function model to center wafer 400.

[0119] The third compensation function model is:

[0120]

[0121] Where K q The integration ratio coefficient for liquid compensation amount, K w The integration ratio coefficient for tilt compensation, K iThis is the scaling factor for the current data during the grinding stage; The weighted average of the difference between the reference current and the applied current, sampled every second during the grinding stage; the above Q, W, and [other parameters] are adjusted for each grinding wheel adjustment. Data, imported into the Y model, K i We'll start with 0.7, and tentatively use 1 for the proportions of the other coefficients. The steepest gradient will then confirm K. q K w With the control coefficients adjusted, the third compensation function model is now complete.

[0122] Current difference calculation: Current data I from the reference side and the applied side is collected every second. 基 (t) and I 加 (t), where the pressurized side and the reference side correspond to two substrates 110, and the weighted average value is calculated:

[0123]

[0124] The weight w(t) can be set according to time decay (e.g., w(t) = e -0.1t ).

[0125] For the third compensation function model:

[0126]

[0127] Initial trial value: Set K q =0.7, K w =1,K i =1;

[0128] Define the total loss function L 总 =∑(Y 实际 -Y 模型 ) 2 ;

[0129] Update coefficients using partial derivatives:

[0130] Similarly, update K. w K i .

[0131] For example: Suppose in a certain adjustment Q = 7.2, W = 30.14, The model output with initial coefficients is:

[0132] Y 模型 =0.7×7.2+1×30.14+1×0.5=5.04+30.14+0.5=35.68

[0133] If the actual demand Y 实际=38, then the loss is (38-35.68)2=5.38, and the target value is gradually approached by adjusting the coefficient.

[0134] As a preferred option, a preset value θ is set, the calculated liquid compensation amount Q is used, and the following judgments are made:

[0135] If the liquid compensation amount Q is less than the preset value θ, the liquid compensation amount Q of the liquid supply port 120 is adjusted based on the first compensation function model to center the wafer 400; if the liquid compensation amount Q is greater than the preset value θ, the liquid compensation amount Q of the liquid supply port 120 and the tilt angle compensation amount W of the grinding wheel 310 are adjusted based on the third compensation function model to center the wafer 400.

[0136] In other words, when Q < θ: only the liquid compensation amount Q is adjusted through the first compensation function model; when Q ≥ θ: the third compensation function model is activated, and Q and the grinding wheel 310 tilt angle compensation amount W are adjusted simultaneously.

[0137] This embodiment also provides a wafer 400 double-sided thinning system applied to a double-sided thinning device. The double-sided thinning device includes a substrate assembly 100, a support assembly 200, a grinding wheel assembly 300, and a drive assembly. The substrate assembly 100 includes two sets of substrates 110, which are arranged opposite to each other. The support assembly 200 includes a carrier ring 210 and a support member 220. The carrier ring 210 is used to support the wafer 400 and is disposed between the two sets of substrates 110. 20 is used to support the carrier ring 210, so that the carrier ring 210 and the wafer 400 can be vertically arranged between the two sets of substrates 110. The support member 220 is rotatable, so that the carrier ring 210 can rotate while being supported by the support member 220. The grinding wheel assembly 300 includes grinding wheels 310, which have two sets. The two sets of grinding wheels 310 are respectively arranged on both sides of the carrier ring 210, so that the grinding wheels 310 can act on the wafer 400 along the axial direction to perform grinding. The drive assembly is used to drive the carrier ring 210 and the wafer 400 to rotate.

[0138] It should be noted that the substrate assembly 100, the carrier assembly 200, the grinding wheel assembly 300, and the drive assembly are all existing double-sided thinning structures, and will not be described in detail in this embodiment.

[0139] The substrate 110 is provided with a liquid supply port 120 for supplying liquid to the wafer 400 to support the wafer 400; the substrate 110 is also provided with a distance sensor 130 for detecting the offset of the wafer 400; specifically, the liquid supply port 120 is used to connect to an external liquid supply source, such as a water tank, and a water pump supplies liquid from the water tank to the liquid supply port 120 so that the liquid flows out from the liquid supply port 120 to support the wafer 400; in one embodiment, multiple liquid supply ports 120 may be provided on each substrate 110; the distance sensor 130 may be a pneumatic gauge, and a pneumatic gauge detection port is provided on the substrate 110 to detect the position of the wafer 400; in one embodiment, multiple pneumatic gauges (distance sensors) may be provided on each substrate 110.

[0140] The double-sided thinning system includes:

[0141] The first parameter acquisition module is used to acquire the pressure change ΔP, the wafer position offset Δx, and the wafer position offset rate between the substrate 110 and the wafer 400.

[0142] The first function establishment module is used to establish first compensation function models for the pressure change ΔP, wafer position offset Δx, and liquid compensation Q between the substrate 110 and the wafer 400; and

[0143] The first adjustment confirmation module is used to confirm the liquid compensation amount Q of the liquid supply port 120 based on the first compensation function model.

[0144] Furthermore, the grinding wheel 310 is rotatable both vertically and horizontally, allowing the grinding wheel 310 to adjust its angle relative to the wafer 400; the system also includes:

[0145] The second parameter acquisition module is used to acquire the surface morphology parameters of the previous wafer and the grinding wheel wear data; among which, the wafer surface morphology parameters include PV curve and BOW value;

[0146] The second function establishment module is used to establish a second compensation function model for the surface topography parameters of the previous wafer, grinding wheel wear data, and tilt angle compensation amount W; and

[0147] The second adjustment confirmation module is used to confirm the tilt compensation amount W of the grinding wheel 310 based on the second compensation function model.

[0148] Furthermore, the system also includes a third parameter acquisition module, which is used to acquire liquid compensation amount Q, tilt angle compensation amount W and grinding current data;

[0149] The third function establishment module is used to establish the third compensation function model for the liquid compensation amount Q, tilt angle compensation amount W, grinding current data, and comprehensive compensation amount Y; and

[0150] The third adjustment confirmation module is used to confirm the liquid compensation amount Q of the liquid supply port 120 and the tilt angle compensation amount W of the grinding wheel 310 based on the third compensation function model.

[0151] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0152] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A wafer double-sided thinning method, applied to a double-sided thinning apparatus, characterized in that, The double-sided thinning device includes: A substrate assembly (100) includes a substrate (110), the substrate (110) having two sets, the two sets of substrates (110) being arranged opposite to each other; A carrier assembly (200) includes a carrier ring (210) and a support member (220). The carrier ring (210) is used to carry a wafer (400). The carrier ring (210) is disposed between two sets of substrates (110), and the support member (220) is used to support the carrier ring (210), so that the carrier ring (210) and the wafer (400) can be vertically arranged between the two sets of substrates (110). A grinding wheel assembly (300) includes two grinding wheels (310), each set of which is disposed on both sides of a carrier ring (210) to grind the wafer (400) axially; and A driving assembly for driving the carrier ring (210) and the wafer (400) to rotate; The substrate (110) is provided with a liquid supply port (120) for supplying liquid to the wafer (400) to support the wafer (400); the substrate (110) is provided with a distance sensor (130) for detecting the offset of the wafer (400). The grinding wheel (310) is rotatable in both the vertical and horizontal directions, so that the angle of the grinding wheel (310) relative to the wafer (400) can be adjusted. The method includes: Obtain the surface morphology parameters and grinding wheel wear data of the previous wafer; wherein, the wafer surface morphology parameters include PV curve and BOW value; Establish a second compensation function model for the surface morphology parameters of the previous wafer and the grinding wheel wear data with respect to the tilt angle compensation amount W; The tilt compensation amount W of the grinding wheel (310) is adjusted based on the second compensation function model to center the wafer (400).

2. The wafer double-sided thinning method according to claim 1, characterized in that, The second compensation function model is: Among them, PV rms K is the root mean square of the peak and trough values ​​in the PV curve. PV For PV rms Control coefficients; △PV1 is the maximum amplitude of the Center-mark in the PV curve; K1 is the control coefficient for △PV1; △PV2 is the maximum amplitude of the B-ring curve in the PV curve; K2 is the control coefficient for △PV2; ΔB is the BOW value; K r ' is the proportionality coefficient of ΔB; K B This is the control coefficient for ΔB; △X represents the wear of the grinding wheel; K X This is the control coefficient for △X.

3. The wafer double-sided thinning method according to claim 2, characterized in that, The method further includes: Acquire fluid compensation Q, tilt angle compensation W, and grinding current data; A third compensation function model is established for the liquid compensation amount Q, the tilt angle compensation amount W, and the grinding current data with respect to the comprehensive compensation amount Y; Based on the third compensation function model, adjust the liquid compensation amount Q of the liquid supply port (120) and the tilt angle compensation amount W of the grinding wheel (310) to center the wafer (400).

4. The wafer double-sided thinning method according to claim 3, characterized in that, The third compensation function model is as follows: Among them, K q This is the proportionality coefficient for the liquid compensation amount; K w This is the proportional coefficient for the tilt compensation amount; K i This is the scaling factor for the current data during the grinding stage; It is a weighted average of the difference between the reference current measured during the grinding stage and the voltage-side current data.

5. A wafer double-sided thinning method according to claim 3 or 4, characterized in that, Set a preset value θ, calculate the liquid compensation amount Q, and determine: If the liquid compensation amount Q < the preset value θ, adjust the liquid compensation amount Q of the liquid supply port (120) based on the first compensation function model to center the wafer (400); If the liquid compensation amount Q > the preset value θ, the liquid compensation amount Q of the liquid supply port (120) and the tilt angle compensation amount W of the grinding wheel (310) are adjusted based on the third compensation function model to make the wafer (400) centered.

6. A wafer double-sided thinning system, applied to a double-sided thinning apparatus, characterized in that, The double-sided thinning device includes: A substrate assembly (100) includes a substrate (110), the substrate (110) having two sets, the two sets of substrates (110) being arranged opposite to each other; A carrier assembly (200) includes a carrier ring (210) and a support member (220). The carrier ring (210) is used to carry a wafer (400). The carrier ring (210) is disposed between two sets of substrates (110), and the support member (220) is used to support the carrier ring (210), so that the carrier ring (210) and the wafer (400) can be vertically arranged between the two sets of substrates (110). A grinding wheel assembly (300) includes two grinding wheels (310), each set of which is disposed on both sides of a carrier ring (210) to grind the wafer (400) axially; and A driving assembly for driving the carrier ring (210) and the wafer (400) to rotate; The substrate (110) is provided with a liquid supply port (120) for supplying liquid to the wafer (400) to support the wafer (400); the substrate (110) is provided with a distance sensor (130) for detecting the offset of the wafer (400). The grinding wheel (310) is rotatable in both the vertical and horizontal directions, so that the angle of the grinding wheel (310) relative to the wafer (400) can be adjusted. The system also includes: The second parameter acquisition module is used to acquire the surface morphology parameters of the previous wafer and the grinding wheel wear data; wherein, the wafer surface morphology parameters include PV curve and BOW value; The second function establishment module is used to establish a second compensation function model for the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the tilt angle compensation amount W; and The second adjustment confirmation module is used to confirm the tilt compensation amount W of the grinding wheel (310) based on the second compensation function model.

7. A wafer double-sided thinning system according to claim 6, characterized in that, Also includes: The third parameter acquisition module is used to acquire liquid compensation amount Q, tilt angle compensation amount W and grinding current data. The third function establishment module is used to establish a third compensation function model for the liquid compensation amount Q, the tilt angle compensation amount W, and the grinding current data with respect to the comprehensive compensation amount Y; and The third adjustment confirmation module is used to confirm the liquid compensation amount Q of the liquid supply port (120) and the tilt angle compensation amount W of the grinding wheel (310) based on the third compensation function model.

Images