A method and system for double-sided thinning of wafers

Abstract

This application relates to the field of wafer processing, and particularly to a method and system for double-sided thinning of wafers, including: obtaining the pressure change amount △P, wafer position offset amount △x, and wafer position offset rate between the substrate and the wafer; establishing a first compensation function model for the pressure change amount △P, wafer position offset amount △x, and liquid compensation amount Q between the substrate and the wafer; adjusting the liquid compensation amount Q of the liquid supply port based on the first compensation function model to center the wafer. A method and system for double-sided thinning of wafers can improve the centering effect of the wafer by controlling the liquid compensation.

Description

Technical Field

[0001] The present application relates to the field of wafer processing, and particularly to a method and system for double-sided thinning of wafers. Background Art

[0002] In a double-sided thinning device, a wafer is vertically placed on an annular carrier, the carrier is arranged between two substrates, fluids are supplied to both sides of the wafer through the substrates to balance the pressure of the wafer, the wafer and the carrier rotate together, and grinding wheels arranged on both sides of the wafer grind two surfaces of the wafer. During the grinding process, the two grinding wheels feed axially until the wafer reaches a thickness meeting the process requirements.

[0003] In the prior art, the grinding wheels on both sides of the wafer act on the wafer. As the wafer continues to be ground and becomes thinner, a large gap is formed between the wafer and the substrate, making the wafer prone to tilt, thus affecting the quality of wafer thinning processing.

[0004] Therefore, the technical problem of the prior art is that the tilt of the wafer during the thinning process affects the processing quality. Summary of the Invention

[0005] The present application provides a method and system for double-sided thinning of wafers, and by controlling liquid compensation and / or inclination compensation, the effect of improving wafer centering is achieved.

[0006] On the one hand, a method for double-sided thinning of wafers provided by the present application adopts the following technical solution:

[0007] A method for double-sided thinning of wafers is applied to a double-sided thinning device. The double-sided thinning device includes: a substrate assembly, the substrate assembly includes substrates, there are two groups of the substrates, and the two groups of substrates are arranged oppositely; a bearing assembly, the bearing assembly includes a carrier ring and a support member, the carrier ring is used to carry the wafer, the carrier ring is arranged between the two groups of substrates, and the support member is used to support the carrier ring so that the carrier ring and the wafer can be vertically arranged between the two groups of substrates; a grinding wheel assembly, the grinding wheel assembly includes grinding wheels, there are two groups of the grinding wheels, and the two groups of grinding wheels are respectively arranged on both sides of the carrier ring so that the grinding wheels can act axially on the wafer for grinding; and a driving assembly, the driving assembly is used to drive the carrier ring and the wafer to rotate; wherein, a liquid supply port for supplying liquid to support the wafer is arranged on the substrate; a distance sensor for detecting the offset amount of the wafer is arranged on the substrate; the method includes: obtaining the pressure change amount △P, the wafer position offset amount △x, and the wafer position offset rate between the substrate and the wafer; establishing a first compensation function model of the pressure change amount △P and the wafer position offset amount △x 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 as follows:

[0009]

[0010] where K r is the proportional coefficient of △x;

[0011] K p is the control coefficient for adjusting the pressure change;

[0012] K x is the control coefficient for adjusting the wafer position offset;

[0013] K dx is the control coefficient for adjusting the wafer position offset rate.

[0014] Preferably, the grinding wheel can rotate in the vertical direction and can also rotate in the horizontal direction so that the grinding wheel can adjust the angle relative to the wafer; the method further includes: obtaining the surface topography parameters of the previous wafer and the grinding wheel wear data; wherein, the wafer surface topography parameters include the PV curve and the BOW value; establishing a second compensation function model of the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the tilt compensation amount W; adjusting the tilt 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 as follows:

[0016]

[0017] where PV rms is the root mean square of the peak-to-valley value in the PV curve graph; K PV is the control coefficient for PV rms ;

[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 in the PV curve; K2 is the control coefficient for △PV2;

[0020] ΔB is the BOW value; K r ’ is the proportional coefficient of ΔB; K B is the control coefficient for ΔB;

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

[0022] Preferably, the method also includes: obtaining liquid compensation amount Q, inclination compensation amount W and grinding current data; establishing a third compensation function model of liquid compensation amount Q, inclination 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 inclination 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] in, is the proportional coefficient of liquid compensation;

[0026] is the proportional coefficient of the tilt compensation;

[0027] is the proportional coefficient of the current data in the grinding stage;

[0028] It is the weighted average of the difference between the baseline current measured in the grinding stage and the current on the pressurized side.

[0029] Preferably, a preset value θ is set, the liquid compensation amount Q is calculated, and a judgment is made: if the liquid compensation amount Q is less than 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 is greater than the preset value θ, the liquid compensation amount Q of the liquid supply port and the inclination 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 present application provides a double-sided wafer thinning system, which adopts the following technical solution:

[0031] A double-sided wafer thinning system is applied to a double-sided thinning device, the double-sided thinning device comprising: a substrate assembly, the substrate assembly comprising two groups of substrates, the two groups of substrates being arranged opposite to each other; a carrying assembly, the carrying assembly comprising a carrying ring and a supporting member, the carrying ring being used to carry the wafer, the carrying ring being arranged between the two groups of substrates, and the supporting member being used to support the carrying ring so that the carrying ring and the wafer can be arranged vertically between the two groups of substrates; a grinding wheel assembly, the grinding wheel assembly comprising a grinding wheel, the grinding wheel having two groups, the two groups of grinding wheels being respectively arranged on both sides of the carrying ring so that the grinding wheel can act on the wafer axially for grinding; and a driving assembly, the driving assembly being used to drive the carrying ring and wafer rotation; 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 the wafer offset; the system comprises: a first parameter acquisition module, the first parameter acquisition module is used to obtain the pressure change △P between the substrate and the wafer, the wafer position offset △x and the wafer position offset rate; a first function establishment module, the first function establishment module is used to establish a first compensation function model of the pressure change △P between the substrate and the wafer, the wafer position offset △x with respect to the liquid compensation amount Q; and a first adjustment confirmation module, the first adjustment confirmation module is used to confirm the liquid compensation amount Q of the liquid supply port based on the first compensation function model.

[0032] Preferably, the grinding wheel can rotate in the vertical direction and in the horizontal direction so that the angle of the grinding wheel can be adjusted compared to the wafer; the system also includes: a second parameter acquisition module, the second parameter acquisition module is used to obtain 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; a second function establishment module, the second function establishment module is used to establish a second compensation function model of the surface morphology parameters of the previous wafer and the grinding wheel wear data with respect to the inclination compensation amount W; and a second adjustment confirmation module, the second adjustment confirmation module is used to confirm the inclination compensation amount W of the grinding wheel based on the second compensation function model.

[0033] Preferably, it also includes: a third parameter acquisition module, which is used to obtain the liquid compensation amount Q, the inclination compensation amount W and the grinding current data; a third function establishment module, which is used to establish a third compensation function model of the liquid compensation amount Q, the inclination compensation amount W and the grinding current data with respect to the 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 inclination 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] By establishing a first compensation function model for the pressure change amount △P, the wafer position offset amount △x, and the liquid compensation amount Q between the substrate and the wafer, and adjusting the liquid supply port compensation amount based on the compensation function model, wafer centering is achieved. Description of the Drawings

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

[0037] Figure 2 is a schematic diagram of the distance measuring sensor on the substrate of the double-sided thinning device described in the present application;

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

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

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

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

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

[0043] Description of the reference numerals: 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 Description of the Embodiments

[0044] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meanings. The "connection" and "coupling" mentioned in the present application, unless otherwise specified, both include direct and indirect connections (couplings). In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0045] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

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

[0047] In order to better understand the above technical solution, the following will be described in detail with reference to the accompanying drawings and specific implementation methods. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0048] The present application provides a double-sided thinning method for a wafer 400, which is applied to a double-sided thinning device, such as Figure 1-3 As shown, the double-sided thinning device includes: a substrate assembly 100, a carrying assembly 200, a grinding wheel assembly 300 and a driving assembly (the driving assembly is not shown in the figure), the substrate assembly 100 includes a substrate 110, the substrate 110 has two groups, and the two groups of substrates 110 are arranged opposite to each other; the carrying assembly 200 includes a carrier ring 210 and a support member 220, the carrier ring 210 is used to carry the wafer 400, the carrier ring 210 is arranged between the two groups of substrates 110, and the support member 220 is used to support the carrier ring 2 10, so that the carrier ring 210 and the wafer 400 can be vertically arranged between the two groups of substrates 110, and the support member 220 can be rotated, so that the carrier ring 210 can be supported by the support member 220 and can rotate at the same time; the grinding wheel assembly 300 includes a grinding wheel 310, and the grinding wheel 310 has two groups. The two groups of grinding wheels 310 are respectively arranged on both sides of the carrier ring 210, so that the grinding wheel 310 can act on the wafer 400 in the axial direction for 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 bearing assembly 200 , the grinding wheel assembly 300 and the driving assembly are all existing double-sided thinning structures, and will not be described again in this embodiment.

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

[0051] Based on the above-mentioned double-sided thinning equipment, this embodiment proposes the following method: Figure 4 As shown, S1.1: obtain the pressure change △P, wafer position offset △x 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 △P and wafer position offset △x 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 calculation of the fluid compensation amount, Q, is based on the pressure change, ΔP, and the wafer position offset, Δx. Q is related to ΔP and Δx, and by using the simultaneous correlation function, the parameters required for dynamic fluid compensation can be calculated. It should be noted that precise fluid compensation is achieved by monitoring the changes in ΔP and Δx in real time and dynamically adjusting the fluid flow rate and pressure based on the calculated results.

[0053] The first compensation function model is:

[0054]

[0055] Among them, K r is the proportionality coefficient of △x;

[0056] K p is the control coefficient used to adjust the pressure change;

[0057] K x is a control coefficient for adjusting wafer position offset;

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

[0059] In one embodiment, the pneumatic measuring instrument monitors the distance between the wafer 400 and the substrate 110 in real time, with 3 monitoring points on each side, for a total of 6 raw data. The wafer position offset Δx at each pneumatic measuring instrument monitoring port isij (i=1, 2, 3, j=1, 2, 3) = x 基ij -x 加ij , j1, j2, and j3 correspond to the values of the tool connection position, the start of the fine grinding stage, and the start of the light grinding stage, respectively.

[0060] The above 9 data are fitted with a curve to obtain the overall wafer 400 deflection state and wafer position offset Δx; at the same time, Δx is sampled every 1 second. ij The numerical value of the grinding stage is fitted to obtain the wafer position deviation rate ;Record the pressure P adjusted manually each time ij (i=1-8 corresponds to 8 liquid supply ports 120, j=1, 2 corresponds to two substrates 110), and the weighted average of each set of data is obtained , ΔP= -Ps (Ps is the standard value 0.2MPa).

[0061] The above Δx, , ΔP value is recorded into the first compensation function model In the meantime, K r Take a trial value of 1 / 2 to verify the deviation between subsequent data and model, and continue to try K r After obtaining a more accurate value, the fastest gradient confirms K p , K x , K dx The control coefficients are equal, and the first compensation function model is now established.

[0062] Data fitting:

[0063] The offset data is directly read and calculated through each pneumatic measuring instrument monitoring port; for the data of three monitoring points in the same stage (such as the knife connection stage), a cubic polynomial fitting is used to obtain the overall offset function , where t is time. For example, the offset function in the cutter connection phase can be expressed as:

[0064]

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

[0066] Offset rate calculation:

[0067] By taking the derivative of the fitting function with respect to time, we can get the rate of change of the offset:

[0068]

[0069] For example, in the fine grinding stage (j=2), if the fitting result is , then the rate is:

[0070]

[0071] Pressure deviation calculation:

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

[0073]

[0074] where the weight w i is set according to the distribution symmetry of the support positions (for example, the weight of the central support position is 0.3, and the weight of the edge support position is 0.1); the pressure deviation is:

[0075]

[0076] The first compensation function model is:

[0077]

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

[0079] Gradient descent optimization:

[0080] Define the loss function: , and calculate the partial derivatives of the loss with respect to each coefficient: , and similarly calculate , .

[0081] Update the coefficients: , where α is the learning rate (for example, α = 0.01); iterate until the loss function converges, such as L < 10 −4 .

[0082] Exemplary:

[0083] Suppose the monitoring data for a certain time is △P = 0.05 MPa, △x = 0.8 μm, = 0.2 μm / s, and the model output under the 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 = 1.5, then the loss is L = (1.5 - 1.144)2 = 0.127; The coefficients are iteratively adjusted through gradient descent, and finally K is optimized to obtain p = 2.1, K x = 1.6, K dx = 0.5 。

[0085] However, limited by the mechanical structure, when the adjustment amount of Q is small (Q ≤ θ), liquid compensation can meet the requirements for adjusting the posture of the wafer 400; but when Q ≥ θ, the inclination compensation of the grinding wheel 310 needs to be combined:

[0086] By combining the Wrap3D image obtained from the calibration wafer on the detection equipment (viewing the overall topography of the simulated wafer 400), the PV curve graph and values (viewing the concavity and convexity degree and amplitude of the Center-mark and B-ring regions, the uniformity and values of the overall PV curve), the BOW curve and values (viewing how the wafer 400 bends on the overall level), and at the same time comprehensively combining the current monitoring situation on both sides of the grinding wheel 310 during each grinding of the grinding wheel 310 and the tooth consumption data of the grinding wheel 310, to adjust the small horizontal angle of the grinding wheel 310 on both sides and the left and right micron-level movement of the tool engagement position of the grinding wheel 310 in the axial direction, so as to accurately adjust the grinding upright state of the wafer 400 and the warping degree of the wafer 400, and to control the parameters of the wafer 400.

[0087] Furthermore, the grinding wheel 310 can rotate in the vertical direction and can also rotate in the horizontal direction, so that the grinding wheel 310 can adjust the angle relative to the wafer 400; in other words, the grinding wheel 310 can be adjusted relative to the wafer 400, so that the wafer 400 can be aligned and centered by adjusting the position of the grinding wheel 310. As Figure 5 shown, the method further includes: S2.1: Obtain the surface topography parameters of the previous wafer and the grinding wheel wear data; wherein, the wafer surface topography parameters include the PV curve and the BOW value; S2.2: Establish a second compensation function model of the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the inclination compensation amount W; S2.3: Adjust the inclination compensation amount W of the grinding wheel 310 based on the second compensation function model to align the wafer 400.

[0088] The second compensation function model is:

[0089]

[0090] wherein, is the root mean square of the peak-to-valley values in the PV curve graph, reflecting the microscopic unevenness of the surface of the wafer 400; is its corresponding control coefficient; is the maximum amplitude of the Center-mark in the PV, is the maximum amplitude of the B-ring in the PV; are their corresponding control coefficients respectively; is the BOW value (including positive and negative), K r 'It is with The coefficient ratios are: is its corresponding control coefficient; is the wear of the grinding wheel. is its corresponding control coefficient;

[0091] like Figure 6 As shown in the PV curve, collect the PV values corresponding to every 25 coordinates from the horizontal coordinates 25 to 250 in the 1st to 4th curves. i (1≤ i ≤11), the root mean square of these data is obtained .

[0092] Select the maximum / minimum value in the horizontal axis range of 100-200 to get , select the maximum / minimum value in the horizontal axis range of 0-50, 250-300 to get .

[0093] Each time the grinding 、 、 , and the aforementioned 、 Data, imported into W model, K r 'Try to take 1.5, and temporarily take the proportion of other coefficients as 1, verify the subsequent data and model deviation value, and keep trying K r After obtaining a more accurate value, the fastest gradient is confirmed. 、 、 、 、 The control coefficients are equal, and the second compensation function model is now established.

[0094] Specific model parameter determination process:

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

[0096] PVrms refers to the root mean square value of the PV curve in a specific area, which is used to quantify the surface micro-roughness. In the range of 25 to 250 on the horizontal axis of the PV curve, a point is taken every 25, for a total of 11 points (coordinates 25, 50, 75,..., 250); the PV value (peak-to-valley difference) of each point is recorded and recorded as PV1, PV2,..., PV 11 ,but

[0097]

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

[0099]

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

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

[0102]

[0103] Example: If the maximum PV value in the area is 10μm and the minimum is 4μm, then △PV1=6um.

[0104] △PV2: In the range of 0-50 and 250-300 on the horizontal axis, take the difference between the maximum and minimum PV values, and then calculate the total:

[0105]

[0106] Example: If the maximum PV in the 0-50 range is 8 um and the minimum is 2 μm; the maximum PV in the 250-300 range is 7 um and the minimum is 3 μm, then: △PV2=max(8,7)-min(2,3)=8-2=6 μm.

[0107] The BOW value (wafer 400 bow) refers to the overall curvature of the wafer 400 analyzed through the Wrap3D image. The BOW value is the height difference between the center and edge of the wafer 400. If the Wrap3D image shows a center concave depth of +5um and an edge warpage of -3um, then: ;

[0108] Grinding wheel wear (ΔX) refers to the thickness reduction of the grinding wheel 310 during the grinding process, which is monitored in real time by the tooth profile sensor. If the thickness of the grinding wheel 310 decreases by 0.1 mm after a certain grinding, then: .

[0109] The second compensation function model is:

[0110] ;

[0111] Set K r '=1.5, the remaining coefficients K PV =1, K1=1, K2=1, K B =1,K X =1;

[0112] Gradient descent optimization:

[0113] Define the loss function:

[0114]

[0115] Compute partial derivatives and update coefficients:

[0116] For example, if PV rms If the item is the maximum value, update K PV : , where β is the learning rate, such as β=0.001.

[0117] Through data from three dimensions: PV curve, BOW curvature, and grinding wheel wear, the causes of wafer 400 posture abnormalities are comprehensively reflected; the max function is used to automatically select the parameter that has the greatest impact on the current state, avoiding the limitations of a single factor; the BOW exponential term and the square root term of grinding wheel wear enhance the model's adaptability to complex processes.

[0118] When the fluid compensation reaches the limit value θ, the grinding wheel 310 tilt compensation value W is further introduced. The adjustment of W is based on the microscopic roughness (rms PV) of the wafer 400 surface, the degree of concavity and convexity in the center-mark and B-ring areas (PV1 and PV2), the uniformity and value of the overall PV curve, the BOW value, and the grinding wheel wear ΔX. By constructing a functional model for W and collecting relevant data, the optimal grinding wheel 310 tilt compensation value can be calculated.

[0119] Therefore, if Figure 7 As shown, the method also includes: S3.1: obtaining liquid compensation amount Q, inclination compensation amount W and grinding current data; S3.2: establishing a third compensation function model of liquid compensation amount Q, inclination compensation amount W, and grinding current data with respect to comprehensive compensation amount Y; S3.3: adjusting the liquid compensation amount Q of the liquid supply port 120 and the inclination compensation amount W of the grinding wheel 310 based on the third compensation function model to center the wafer 400.

[0120] The third compensation function model is:

[0121]

[0122] in is the integration proportional coefficient of the liquid compensation amount, is the integration proportional coefficient of the tilt compensation amount, is the proportional coefficient of the current data in the grinding stage; The weighted average of the difference between the reference current and the pressurized side current data sampled every second during the grinding stage; the Q, W, Data, imported into the Y model, Try it with 0.7, and temporarily take the other coefficient ratios as 1, and confirm the fastest gradient 、 The control coefficients are equal, and the third compensation function model is now established.

[0123] Current difference calculation: collect current data of reference side and pressurized side I every second 基 (t) and I 加 (t), where the pressurized side and the reference side correspond to the two substrates 110, and a weighted average value is calculated:

[0124] =

[0125] The weight w(t) can be set according to time decay (e.g. w(t)=e −0.1t ).

[0126] For the third compensation function model:

[0127]

[0128] Initial trial value: Set K q = 0.7, K w = 1, K i = 1;

[0129] Define the total loss function ;

[0130] Update the coefficients via partial derivatives: ;

[0131] Similarly, update K w , K i .

[0132] For example: Assume that in a certain adjustment, Q=7.2, W=30.14, =0.5, the model output under the initial coefficient is:

[0133]

[0134] If the actual demand is 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.

[0135] As a preference, a preset value θ is set, the calculated liquid compensation amount Q is determined:

[0136] 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 align the wafer 400; if the liquid compensation amount Q > the preset value θ, adjust the liquid compensation amount Q of the liquid supply port 120 and the inclination compensation amount W of the grinding wheel 310 based on the third compensation function model to align the wafer 400.

[0137] In other words, when Q < θ: only adjust the liquid compensation amount Q through the first compensation function model; when Q ≥ θ: activate the third compensation function model and adjust Q and the inclination compensation amount W of the grinding wheel 310 simultaneously.

[0138] This embodiment also provides a double-sided thinning system for the wafer 400, which is applied to a double-sided thinning device. The double-sided thinning device includes a substrate assembly 100, a carrier assembly 200, a grinding wheel assembly 300, and a driving assembly. The substrate assembly 100 includes substrates 110, and there are two groups of substrates 110 arranged oppositely; the carrier assembly 200 includes a carrier ring 210 and a support member 220. The carrier ring 210 is used to carry the wafer 400, and the carrier ring 210 is arranged between the two groups of substrates 110. 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 groups 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, and there are two groups of grinding wheels 310 respectively arranged on both sides of the carrier ring 210, so that the grinding wheels 310 can act on the wafer 400 axially for grinding; the driving assembly is used to drive the carrier ring 210 and the wafer 400 to rotate.

[0139] It should be noted that the substrate assembly 100, the carrier assembly 200, the grinding wheel assembly 300, and the driving assembly are all existing double-sided thinning structures, and will not be elaborated in this embodiment.

[0140] Among them, a liquid supply port 120 for supplying liquid to the wafer 400 to support the wafer 400 is provided on the substrate 110; a distance sensor 130 for detecting the offset amount of the wafer 400 is provided on the substrate 110; specifically, the liquid supply port 120 is used to connect an external liquid supply source, such as a water tank, etc. The water tank supplies liquid to the liquid supply port 120 through a water pump, so that the liquid flows out of 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 adopt 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.

[0141] The double-sided thinning system includes:

[0142] A first parameter acquisition module, the first parameter acquisition module is used to obtain the pressure change ΔP between the substrate 110 and the wafer 400, the wafer position offset Δx, and the wafer position offset rate;

[0143] A first function establishment module, the first function establishment module is used to establish a first compensation function model of the pressure change ΔP between the substrate 110 and the wafer 400, the wafer position offset Δx, and the liquid compensation amount Q; and

[0144] 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.

[0145] Furthermore, the grinding wheel 310 is rotatable in the vertical direction and in the horizontal direction, so that the angle of the grinding wheel 310 relative to the wafer 400 can be adjusted. The system further includes:

[0146] A second parameter acquisition module is used to obtain the surface topography parameters of the previous wafer and the grinding wheel wear data; wherein the wafer surface topography parameters include PV curve and BOW value;

[0147] A second function establishment module, the second function establishment module is used to establish a second compensation function model of the surface topography parameters of the previous wafer, the grinding wheel wear data and the tilt angle compensation amount W; and

[0148] The second adjustment confirmation module is used to confirm the inclination compensation amount W of the grinding wheel 310 based on the second compensation function model.

[0149] Furthermore, the system further comprises: a third parameter acquisition module, the third parameter acquisition module being used to acquire liquid compensation amount Q, tilt angle compensation amount W and grinding current data;

[0150] A third function establishment module, the third function establishment module is used to establish a third compensation function model of the liquid compensation amount Q, the inclination compensation amount W, the grinding current data and the comprehensive compensation amount Y; and

[0151] The third adjustment confirmation module is used to confirm the liquid compensation amount Q of the liquid supply port 120 and the inclination compensation amount W of the grinding wheel 310 based on the third compensation function model.

[0152] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0153] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for double-sided thinning of a wafer, applied to a double-sided thinning device, characterized in that The double-sided thinning device includes: A substrate assembly (100), the substrate assembly (100) includes a substrate (110), there are two groups of the substrates (110), and the two groups of substrates (110) are arranged oppositely; A carrying assembly (200), the carrying 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 arranged between the two groups 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 groups of substrates (110); A grinding wheel assembly (300), the grinding wheel assembly (300) includes grinding wheels (310), there are two groups of the grinding wheels (310), and the two groups 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) axially for grinding; and A driving assembly, the driving assembly is used to drive the carrier ring (210) and the wafer (400) to rotate; Wherein, a liquid supply port (120) for supplying liquid to the wafer (400) to support the wafer (400) is arranged on the substrate (110); a distance sensor (130) for detecting the offset amount of the wafer (400) is arranged on the substrate (110); The method includes: Obtaining the pressure change amount △P, the wafer position offset amount △x and the wafer position offset rate between the substrate (110) and the wafer (400); Establishing a first compensation function model of the pressure change amount △P and the wafer position offset amount △x between the substrate (110) and the wafer (400) with respect to the liquid compensation amount Q; Adjusting the liquid compensation amount Q of the liquid supply port (120) based on the first compensation function model to align the wafer (400); Establishing a second compensation function model of the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the inclination compensation amount W of the grinding wheel; Establishing a third compensation function model of the liquid compensation amount Q, the inclination compensation amount W and the grinding current data with respect to the comprehensive compensation amount Y; Setting a preset value θ, calculating the liquid compensation amount Q, and judging: If the liquid compensation amount Q < the preset value θ, adjusting the liquid compensation amount Q of the liquid supply port (120) based on the first compensation function model to align the wafer (400); If the liquid compensation amount Q > the preset value θ, adjusting the liquid compensation amount Q of the liquid supply port (120) and the inclination compensation amount W of the grinding wheel (310) based on the third compensation function model to align the wafer (400).

2. The method for double-sided thinning of a wafer according to claim 1, wherein The first compensation function model is: ； Among them, K r is the proportionality coefficient of △x; K p is the control coefficient for adjusting the pressure change; K x is a control coefficient for adjusting the wafer position offset; K dx is a control coefficient for adjusting the wafer position offset rate.

3. A method for double-sided thinning of a wafer according to claim 2, characterized in that, Making the grinding wheel (310) rotatable in the vertical direction and rotatable in the horizontal direction so that the grinding wheel (310) can adjust the angle relative to the wafer (400); The method further includes: Obtaining the surface topography parameters of the previous wafer and the grinding wheel wear data; wherein, the wafer surface topography parameters include a PV curve and a BOW value; Establishing a second compensation function model of the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the inclination compensation amount W; Adjust the inclination compensation amount W of the grinding wheel (310) based on the second compensation function model to center the wafer (400).

4. A method for double-sided thinning of a wafer according to claim 3, characterized in that, The method further includes: Obtain the liquid compensation amount Q, the inclination compensation amount W, and the grinding current data; Establish a third compensation function model of the liquid compensation amount Q, the inclination compensation amount W, and the grinding current data with respect to the comprehensive compensation amount Y; Adjust the liquid compensation amount Q of the liquid supply port (120) and the inclination compensation amount W of the grinding wheel (310) based on the third compensation function model to center the wafer (400).

5. A method for double-sided thinning of a wafer according to claim 4, characterized in that The third compensation function model is: ； Among them, is the proportionality coefficient of the liquid compensation amount; is the proportionality coefficient of the inclination compensation amount; is the proportionality coefficient of the current data in the grinding stage; It is the weighted average of the difference between the current data on the reference side and the current data on the pressurized side during the grinding stage.

6. A wafer double-sided thinning system, applied to a double-sided thinning device, is characterized in that The double-sided thinning device includes: A substrate assembly (100), the substrate assembly (100) includes a substrate (110), there are two groups of the substrates (110), and the two groups of substrates (110) are arranged oppositely; A carrier assembly (200), the carrier assembly (200) includes a carrier ring (210) and a support member (220), the carrier ring (210) is used to carry the wafer (400), the carrier ring (210) is arranged between the two groups 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 groups of substrates (110); A grinding wheel assembly (300), the grinding wheel assembly (300) includes a grinding wheel (310), there are two groups of the grinding wheels (310), and the two groups of grinding wheels (310) are respectively arranged on both sides of the carrier ring (210) so that the grinding wheel (310) can act on the wafer (400) axially for grinding; and A driving assembly for driving the carrier ring (210) and the wafer (400) to rotate; Wherein, a liquid supply port (120) for supplying liquid to the wafer (400) to support the wafer (400) is arranged on the substrate (110); a distance sensor (130) for detecting the offset amount of the wafer (400) is arranged on the substrate (110); The system includes: A first parameter acquisition module for acquiring the pressure change amount △P, the wafer position offset amount △x, and the wafer position offset rate between the substrate (110) and the wafer (400); A first function establishment module for establishing a first compensation function model of the pressure change amount △P and the wafer position offset amount △x between the substrate (110) and the wafer (400) with respect to the liquid compensation amount Q; and A first adjustment confirmation module for confirming the liquid compensation amount Q of the liquid supply port (120) based on the first compensation function model; Establish a second compensation function model of the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the inclination compensation amount W of the grinding wheel; Establish a third compensation function model of the liquid compensation amount Q, the inclination compensation amount W, and the grinding current data with respect to the comprehensive compensation amount Y; Set a preset value θ, calculate the liquid compensation amount Q, and judge: 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 inclination compensation amount W of the grinding wheel (310) are adjusted based on the third compensation function model to center the wafer (400).

7. The wafer double-sided thinning system according to claim 6, characterized in that The grinding wheel (310) is rotatable in the vertical direction and rotatable in the horizontal direction so that the grinding wheel (310) can adjust the angle relative to the wafer (400); The system further includes: A second parameter acquisition module, which is used to acquire the surface topography parameters of the previous wafer and the grinding wheel wear data; wherein, the wafer surface topography parameters include the PV curve and the BOW value; A second function establishment module, which is used to establish a second compensation function model of the surface topography parameters of the previous wafer and the grinding wheel wear data with respect to the inclination compensation amount W; and A second adjustment confirmation module, which is used to confirm the inclination compensation amount W of the grinding wheel (310) based on the second compensation function model.

8. A wafer double-sided thinning system according to claim 7, wherein It further includes: A third parameter acquisition module, which is used to acquire the liquid compensation amount Q, the inclination compensation amount W, and the grinding current data; A third function establishment module, which is used to establish a third compensation function model of the liquid compensation amount Q, the inclination compensation amount W, and the grinding current data with respect to the 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 (120) and the inclination compensation amount W of the grinding wheel (310) based on the third compensation function model.

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