Control system and method for a wafer cassette load port

Abstract

The present application belongs to the technical field of intelligent control, and provides a control system and method for a wafer box loading port. If the correlation between the suction area and the sag distance is relatively close, the correlation adjustment coefficient is obtained, the number of suction cup adjustments is obtained, and whether the suction cup distribution strategy in the multiple historical taking processes is reasonable is analyzed. If not, the distribution of the suction cups is adjusted according to the number of suction cup adjustments, and a suction cup distribution map is constructed. On the one hand, by adjusting the distance between the suction cup and the center of the thin wafer, the probability of the thin wafer tilting in the taking process of the edge suction cup is reduced. On the other hand, by adjusting the circumferential angle of the suction cup on the thin wafer, the circumferential angle distribution of the suction cup on the thin wafer is uniform, the stability of the suction cup in the process of taking the thin wafer is avoided, and the probability of collision with the adjacent thin wafer in the process of taking the thin wafer is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of intelligent control, in particular to a control system and method of a wafer box loading port. BACKGROUND

[0002] In the field of semiconductor manufacturing, wafers as core raw materials, the accuracy and stability of the processing process play a decisive role in the quality of the final product. Wafer box loading port as a key link of wafer transmission and storage, undertakes the important task of safe and efficient transfer of wafers between devices. However, in the actual production process, wafer box loading port faces many technical challenges, which seriously affects the efficiency and quality of wafer processing.

[0003] In the prior art, it is difficult for the staff to clearly understand the distribution interval of the thin wafers in the three-dimensional space, and it is difficult to develop a targeted picking strategy when picking the thin wafers. Moreover, the prior art cannot identify the instantaneous sag risk caused by insufficient adsorption contact area in real time. When the adsorption contact area is insufficient, the wafer may sag instantaneously during the picking process. Therefore, the instantaneous sag distance in each historical picking process is compared with the corresponding thin wafer interval in real time to identify the instantaneous sag risk and ensure the safety of the wafer picking process.

[0004] Secondly, the distribution strategy of the suction cups on the thin wafers directly affects the stability of wafer picking. In the prior art, there is a lack of effective analysis method for whether the suction cup distribution strategy is reasonable. On the one hand, if the distance between the suction cup and the center of the thin wafer is not properly adjusted, the edge suction cup is likely to cause the thin wafer to tilt during the picking process, increasing the risk of wafer damage. On the other hand, uneven distribution of the suction cups on the circumference of the thin wafer will affect the stability of the suction cups during the picking process, which is also likely to cause the wafer to collide with the adjacent thin wafer during the picking process. Therefore, the suction cup distribution strategy in the historical picking process is analyzed to determine whether it is reasonable, and the suction cup distribution is adjusted according to the number of suction cups when it is not reasonable, thereby constructing a suction cup distribution map to improve the stability of wafer picking and reduce the collision probability.

[0005] Therefore, the application provides a control system and method of a wafer box loading port. SUMMARY

[0006] In order to make up for the shortcomings of the prior art and solve at least one technical problem in the background art.

[0007] The technical solution adopted by the application to solve its technical problems is:

[0008] In a first aspect, a control method of a wafer box loading port includes:

[0009] A wafer box is taken as a basis to construct a wafer box three-dimensional model, and a thin wafer area in the wafer box three-dimensional model is extracted to analyze a thin wafer spacing, and the thin wafer spacing is obtained;

[0010] The instantaneous sag distance in each historical taking process is obtained, and the corresponding thin wafer spacing is compared in risk to determine a comparison risk degree, if the risk degree is high, the adsorption contact area in each historical taking process is combined for correlation analysis to determine the correlation degree between the adsorption contact area and the sag distance;

[0011] If the correlation between the adsorption contact area and the sag distance is close, an associated adjustment coefficient is obtained, the number of suction discs is obtained, and whether the distribution strategy of the suction discs in the historical taking process is reasonable is analyzed;

[0012] If it is not reasonable, the distribution of the suction discs is adjusted according to the number of the suction discs, and a suction disc distribution diagram is constructed.

[0013] Preferably, the thin wafer spacing is obtained as follows:

[0014] The length inside the wafer box is taken as the Y axis, the width inside the wafer box is taken as the X axis, and the height inside the wafer box is taken as the Z axis to construct a wafer box three-dimensional model, the thin wafer area in the wafer box three-dimensional model is extracted, and adjacent thin wafers in the thin wafer area are combined to obtain a plurality of thin wafer combinations;

[0015] The distance between adjacent thin wafers in each thin wafer combination is obtained as the thin wafer spacing.

[0016] Preferably, the comparison risk degree is determined as follows:

[0017] The Z axis coordinate of the thin wafer actually on the wafer box three-dimensional model after each historical taking is obtained, and the Z axis coordinate of the thin wafer theoretically on the wafer box three-dimensional model is subtracted to obtain an absolute value, and the Z axis length is calculated by ratio to obtain the instantaneous sag distance;

[0018] The instantaneous sag distance and the corresponding thin wafer spacing are calculated by ratio to output the comparison risk degree.

[0019] Preferably, if the risk degree is high, the adsorption contact area in each historical taking process is combined for correlation analysis as follows:

[0020] If the comparison risk degree is greater than a comparison risk degree threshold, a high risk signal is displayed, the shape of the bottom of the suction disc is taken as a circular shape, the area of the bottom of each suction disc is obtained by using a circular area calculation formula, the sum is calculated, and the thin wafer surface area is calculated by ratio to obtain the adsorption contact area;

[0021] The adsorption contact area and the comparison risk degree in each historical taking process are taken as a set of correlation analysis data sets, a plurality of sets of correlation analysis data sets are obtained, the adsorption contact area and the comparison risk degree in each set of correlation analysis data sets are extracted, and the adsorption contact area sequence and the comparison risk sequence are obtained by sorting and summarizing according to the time sequence corresponding to the historical taking.

[0022] In the comparison risk sequence, adjacent comparison risk degrees are combined to obtain adjacent comparison risk combinations, the adjacent adsorption contact areas in each adjacent comparison risk combination are subtracted, and the adjacent comparison risk degrees are subtracted to obtain a single set of adsorption contact differences and a single set of comparison risk differences.

[0023] Preferably, the correlation degree between the adsorption contact area and the sag distance is determined as follows:

[0024] All single sets of adsorption contact differences and single sets of comparison risk differences are processed by using the Pearson correlation coefficient calculation method to obtain correlation analysis values.

[0025] If the correlation analysis value is greater than or equal to the correlation analysis threshold value, a correlation close signal is displayed.

[0026] Preferably, the correlation adjustment coefficient is obtained to obtain the number of adjusted suction cups, and the process is as follows:

[0027] All unit correlation coefficients are averaged to obtain the correlation adjustment coefficient;

[0028] The comparison risk degree threshold value is compared with the correlation adjustment coefficient to obtain the adjusted adsorption contact area quantity, which is summed with the current adsorption contact area to obtain the adjusted adsorption contact area, and the adjusted adsorption contact area is compared with the adsorption area corresponding to each suction cup to obtain the number of adjusted suction cups.

[0029] Preferably, whether the suction cup distribution strategy in the historical taking process is reasonable is analyzed, and the process is as follows:

[0030] On the thin wafer surface, the center of each suction cup bottom and the center of the thin wafer surface are extracted, the distance between the center of each suction cup bottom and the center of the thin wafer surface is obtained, and the distance is compared with the circumference of the thin wafer surface to obtain a unit radial distance, and all unit radial distances are averaged to obtain a radial distance average.

[0031] The centers of adjacent suction cup bottoms are connected by a straight line, and the centers of adjacent suction cup bottoms are respectively connected with the center of the thin wafer surface by a straight line to construct a fitting triangle.

[0032] The distance between the centers of adjacent suction cup bottoms is obtained as the side length of the fitting triangle A.

[0033] Respectively, the distance between the center of the bottom of the adjacent suction cup and the center of the surface of the thin wafer is taken as the length of the fitting triangle B and the length of the fitting triangle C;

[0034] The length of the fitting triangle A, the length of the fitting triangle B and the length of the fitting triangle C are all input into the cosine theorem formula, and are calculated by ratio with the circumferential angle, and the unit circumferential angle is output;

[0035] The difference between the circumferential angle and the average radial distance is summed up, and the distribution strategy evaluation value is output, and if the distribution strategy evaluation value is greater than the distribution strategy evaluation threshold, a distribution strategy low matching signal is displayed.

[0036] Preferably, the distribution of the suction cups is adjusted according to the number of suction cup adjustments, and the process is as follows:

[0037] The circumferential angle is calculated by ratio with the number of suction cup adjustments, and the average circumferential angle is output;

[0038] The distribution strategy evaluation threshold is calculated by ratio with the number of suction cup adjustments, and the adjusted radial value is output, and is subtracted from the unit radial distance to obtain the unit radial adjustment amount.

[0039] Preferably, the construction process of the suction cup distribution map is as follows:

[0040] According to the adjusted radial value and the average circumferential angle, each suction cup is placed on the corresponding angle line on the surface of the thin wafer to construct the suction cup distribution map.

[0041] Secondly, a control system of a wafer box loading port comprises:

[0042] A three-dimensional model of the wafer box is constructed according to the length, width and height of the wafer box, and a thin wafer area in the three-dimensional model of the wafer box is extracted, and the distribution spacing of the thin wafer is analyzed to obtain a thin wafer spacing.

[0043] A correlation analysis module: the instantaneous sag distance in each historical taking process is obtained, and the corresponding thin wafer spacing is compared in risk to determine the risk degree, and if the risk degree is high, the correlation between the suction contact area in each historical taking process and the sag distance is analyzed to determine the correlation degree between the suction contact area and the sag distance.

[0044] An adjustment evaluation module: if the correlation between the suction contact area and the sag distance is close, an adjustment correlation coefficient is obtained, the number of suction cup adjustments is obtained, and whether the distribution strategy of the suction cup in the historical taking process is reasonable is analyzed.

[0045] A distribution adjustment module: if it is not reasonable, the distribution of the suction cup is adjusted according to the number of suction cup adjustments, and a suction cup distribution map is constructed.

[0046] The beneficial effects of the present application are as follows:

[0047] The present application constructs a wafer box three-dimensional model according to the wafer placement environment in the wafer box, extracts the thin wafer area, obtains the distribution spacing of the thin wafers in the thin wafer area, obtains the thin wafer spacing, is beneficial to the analysis of the adjacent relationship of the thin wafers in multiple spatial directions, makes the staff more clearly understand the distribution spacing of the thin wafers in the three-dimensional space, formulates a targeted taking strategy for subsequent taking of the thin wafers, reduces the probability of collision with adjacent thin wafers in the taking process, obtains the instantaneous sag distance in each historical taking process, and compares and analyzes the risk with the corresponding thin wafer spacing to determine the comparison risk degree, if the risk is high, the correlation analysis of the adsorption contact area in each historical taking process is carried out to determine the correlation degree between the adsorption contact area and the sag distance, which is helpful to real-time identification of the instantaneous sag risk caused by insufficient adsorption contact area, triggering of the loading port control system to automatically adjust the parameters of the suction cup to avoid collision with the vertically lower wafer, and providing design optimization basic data for the thin wafer loading density (spacing) in the wafer box through the uniform distribution analysis of the thin wafers in the thin wafer area, and optimizing the design of the thin wafer loading density in the wafer box;

[0048] If the correlation between the adsorption contact area and the sag distance is relatively close, the correlation adjustment coefficient is obtained, the number of suction cup adjustments is obtained, and whether the distribution strategy of the suction cup in the multiple historical taking processes is reasonable is analyzed, if not, the distribution of the suction cup is adjusted according to the number of suction cup adjustments, and a suction cup distribution map is constructed, on the one hand, the distance between the suction cup and the center of the thin wafer is adjusted to reduce the probability of thin wafer inclination in the taking process of the edge suction cup, on the other hand, the circumferential angle of the suction cup on the thin wafer is adjusted to make the circumferential angle of the suction cup on the thin wafer uniform, avoid affecting the stability of the suction cup in the process of taking the thin wafer, and reduce the probability of collision with adjacent thin wafers in the process of taking the thin wafer. BRIEF DESCRIPTION OF DRAWINGS

[0049] The present application will be further described below with reference to the accompanying drawings.

[0050] Figure 1 is a step flow chart of the control method of the wafer box loading port of the present application;

[0051] Figure 2 is a judgment flow chart of the control method of the wafer box loading port of the present application;

[0052] Figure 3 is a schematic diagram of the control system of the wafer box loading port of the present application. DETAILED DESCRIPTION

[0053] In order to make the technical means, creative features, purposes and effects realized by the present application easy to understand, the present application will be further described below with reference to the specific embodiments.

[0054] Embodiment 1:

[0055] As shown in the control method of the wafer box loading port provided by the embodiment of the present application, the method comprises the following steps: Figure 1 - Figure 2 As shown in the control method of the wafer box loading port provided by the embodiment of the present application, the method comprises the following steps:

[0056] Step 1: Space conversion is performed on the wafer placement environment in the wafer box to construct a wafer box three-dimensional model, extract a thin wafer area, and obtain the distribution interval of the thin wafers in the thin wafer area to obtain a thin wafer interval.

[0057] In some embodiments, the length inside the wafer box is taken as the Y axis, the width inside the wafer box is taken as the X axis, and the height inside the wafer box is taken as the Z axis to construct the wafer box three-dimensional model, and the specific process is as follows:

[0058] For example, the chessboard method is used to calibrate the top camera and the four side cameras respectively to determine the focal length, focal point position and distortion coefficient of each camera. After calibration, each pixel coordinate obtained by each camera is converted into a physical coordinate, and the wafer box three-dimensional model is constructed according to the converted physical coordinate.

[0059] The thin wafer area in the wafer box three-dimensional model is extracted, and adjacent thin wafers in the thin wafer area are combined to obtain a plurality of thin wafer combinations.

[0060] It should be noted that the plurality of thin wafer combinations includes horizontally adjacent thin wafers and vertically adjacent thin wafers, wherein the horizontally adjacent thin wafers include X-axis horizontally adjacent thin wafers and Y-axis horizontally adjacent thin wafers, and the vertically adjacent thin wafers include Z-axis vertically adjacent thin wafers.

[0061] The distance between adjacent thin wafers in each thin wafer combination is obtained, and mean value calculation is performed to obtain a thin wafer interval.

[0062] The distance between adjacent thin wafers in each thin wafer combination is obtained by taking each thin wafer in the thin wafer area as a thin wafer point in the wafer box three-dimensional model, using the coordinate distance formula to obtain the distance between adjacent thin wafer points in each thin wafer combination, and performing ratio calculation with the length of the corresponding coordinate axis in the wafer box three-dimensional model.

[0063] For example, if the analyzed thin wafer combination is X-axis horizontally adjacent thin wafers or Y-axis horizontally adjacent thin wafers, after the distance between adjacent thin wafer points in each thin wafer combination is obtained by using the coordinate distance formula, ratio calculation is performed with the length of the X or Y coordinate axis in the wafer box three-dimensional model (the width inside the wafer box or the length inside the wafer box).

[0064] When the analyzed thin wafer combination is a Z-axis vertical adjacent thin wafer, the distance between the points of the adjacent thin wafers in each thin wafer combination is obtained by using the coordinate distance formula, and then a ratio calculation is performed with the length of the Z-axis coordinate in the three-dimensional model of the corresponding wafer box (the height inside the wafer box).

[0065] Specifically, obtaining the thin wafer spacing is beneficial to: combining the adjacent thin wafers in the thin wafer area into multiple thin wafer combinations, including horizontal adjacent thin wafers (X-axis horizontal adjacent thin wafers and Y-axis horizontal adjacent thin wafers) and vertical adjacent thin wafers (Z-axis vertical adjacent thin wafers), analyzing the adjacent relationship of the thin wafers from multiple spatial directions, so that the staff can more clearly understand the distribution spacing of the thin wafers in the three-dimensional space.

[0066] Secondly, since there is a spatial limitation in the wafer box, the thin wafers are prone to collision with adjacent thin wafers during the taking process, therefore, after understanding the distribution spacing of the thin wafers in the three-dimensional space, a targeted taking strategy can be formulated for subsequent taking of the thin wafers, reducing the probability of collision with adjacent thin wafers during the taking process.

[0067] Step two: in the process of taking the thin wafers multiple times, the instantaneous sag distance in each historical taking process is obtained, and a risk comparison analysis is performed with the corresponding thin wafer spacing to determine the comparison risk degree, if the risk is high, then the correlation analysis is performed in combination with the adsorption contact area in each historical taking process to determine the correlation degree between the adsorption contact area and the sag distance.

[0068] In some embodiments, the determination process of the comparison risk degree is as follows:

[0069] The Z-axis coordinate of the actual thin wafer after each historical taking on the three-dimensional model of the wafer box is obtained by using the laser displacement sensor, and the Z-axis coordinate of the theoretical thin wafer on the three-dimensional model of the wafer box is obtained, the absolute value is obtained by subtracting, and the ratio calculation is performed with the length of the Z-axis, to obtain the instantaneous sag distance;

[0070] The instantaneous sag distance is compared with the corresponding thin wafer spacing to obtain the comparison risk degree by ratio calculation;

[0071] It should be noted that the meaning of the corresponding thin wafer spacing is: for example, when taking the thin wafer from the wafer box, since there is a limitation in the space inside the wafer box, the thin wafer can only be taken by horizontal extraction, but at the moment when the suction cup adsorbs the thin wafer for taking, there will be an instantaneous sag phenomenon, which is prone to cause collision with the vertically placed thin wafer below, therefore, the corresponding thin wafer spacing is the distance between the taken thin wafer and the vertically placed thin wafer below when taking the thin wafer;

[0072] If the comparison risk degree is less than or equal to the comparison risk degree threshold value, it indicates that in the analyzed historical taking process, the instantaneous sag phenomenon occurring when the thin wafer is adsorbed by the suction cup leads to a relatively small probability of collision with the thin wafer placed vertically below;

[0073] If the comparison risk degree is greater than the comparison risk degree threshold value, it indicates that in the analyzed historical taking process, the instantaneous sag phenomenon occurring when the thin wafer is adsorbed by the suction cup leads to a relatively large probability of collision with the thin wafer placed vertically below;

[0074] If the probability is relatively large, the adsorption contact area is analyzed in association with the comparison risk degree, and the process is as follows:

[0075] Taking a circular shape as an example, the area of the bottom of each suction cup is obtained by using the circular area calculation formula as the adsorption contact area;

[0076] It should be noted that in each historical taking process, each suction cup is in complete contact with the surface of the thin wafer, and there is no gap between the suction cup and the surface of the thin wafer.

[0077] The adsorption area corresponding to each suction cup is summed up and calculated by ratio with the surface area of the thin wafer to obtain the adsorption contact area;

[0078] It should be noted that the surface of the thin wafer is usually circular, and can also be obtained by the circular area calculation formula;

[0079] The adsorption contact area in each historical taking process and the comparison risk degree are taken as a set of associated analysis data groups to obtain multiple sets of associated analysis data groups;

[0080] The adsorption contact area in each set of associated analysis data groups is extracted and sorted and summarized according to the time sequence corresponding to the historical taking to obtain an adsorption area sequence;

[0081] In the adsorption area sequence, adjacent adsorption contact areas are combined to obtain adjacent adsorption combinations;

[0082] Similarly, the comparison risk degree in each set of associated analysis data groups is extracted and sorted and summarized according to the time sequence corresponding to the historical taking to obtain a comparison risk sequence;

[0083] In the comparison risk sequence, adjacent comparison risk degrees are combined to obtain adjacent comparison risk combinations;

[0084] In the adjacent adsorption combination, the adjacent adsorption contact areas are subtracted to obtain a single adsorption difference;

[0085] In the adjacent ratio combination, the adjacent ratio is subtracted from the risk degree, and the absolute value is obtained as a single group ratio difference;

[0086] The data of all single group adsorption contact differences and single group ratio differences are processed by using the Pearson correlation coefficient calculation method, and the specific process is as follows:

[0087] S1, the average values of all single group adsorption contact differences and all single group ratio differences are obtained, respectively, to obtain the average value of the adsorption contact difference and the average value of the ratio difference ;

[0088] S2, the covariance corresponding to all single group adsorption contact differences and the covariance corresponding to all single group ratio differences are obtained, respectively, to obtain the adsorption contact covariance and the ratio covariance, and the sum is calculated to obtain the numerator in the Pearson correlation coefficient calculation formula ; m represents the total number of single group adsorption contact differences, and also represents the total number of single group ratio differences, wherein the total number of single group adsorption contact differences is equal to the total number of single group ratio differences;

[0089] S3, the sum of squares of deviations corresponding to all single group adsorption contact differences and the sum of squares of deviations corresponding to all single group ratio differences are obtained, respectively, to obtain the sum of squares of deviations of adsorption contact and the sum of squares of deviations of ratio, as the denominator in the Pearson correlation coefficient calculation formula ; m represents the total number of single group adsorption contact differences, and also represents the total number of single group ratio differences, wherein the total number of single group adsorption contact differences is equal to the total number of single group ratio differences;

[0090] S4, according to the numerator and denominator in the Pearson correlation coefficient calculation formula, input into the improved Pearson correlation coefficient calculation formula, and calculate to obtain the correlation analysis value ;

[0091] Specifically, ;

[0092] If the correlation analysis value is greater than or equal to the correlation analysis threshold value, it indicates that the correlation degree between the adsorption contact area and the ratio risk degree is relatively close, and the correlation close signal is displayed;

[0093] If the correlation analysis value is less than the correlation analysis threshold value, it indicates that the correlation degree between the adsorption contact area and the ratio risk degree is relatively not close, and the correlation non-close signal is displayed;

[0094] It should be noted that since the data of all single group adsorption contact differences and single group ratio differences are calculated and processed by using the Pearson correlation coefficient calculation formula, the calculated value is in the interval, the original Pearson correlation coefficient calculation formula is processed by absolute value, therefore, the calculated value is in the The principle behind the Pearson correlation coefficient calculation formula is that the closer it is to 1, the stronger the linear positive correlation; the closer it is to -1, the stronger the linear negative correlation; and the closer it is to 0, the weaker the linear correlation.

[0095] Specifically, correlation analysis is beneficial for: identifying the risk of instantaneous sagging caused by insufficient adsorption contact area in real time, triggering the loading port control system to automatically adjust the suction cup parameters, and avoiding collision with the wafer vertically below;

[0096] Secondly, to increase the adsorption contact area, the bottom of the suction cup can be designed as an arc-shaped adsorption plate and a sealing groove can be added. This provides an adjustment idea for the bottom design of the suction cup and reduces the risk of wafer slippage due to unstable adsorption.

[0097] Furthermore, by combining the analysis of the uniform distribution of thin wafers within the thin wafer area, basic data for design optimization of the thin wafer loading density (spacing) within the wafer box is provided, and the thin wafer loading density within the wafer box is optimized in a targeted manner.

[0098] The solution in this embodiment is as follows: A three-dimensional model of the wafer cassette is constructed based on the wafer placement environment within the cassette, and a thin wafer region is extracted. The uniformity of the thin wafer distribution within this region is analyzed to diagnose whether the thin wafer distribution is uniform. This facilitates the analysis of the adjacency relationships of the thin wafers in multiple spatial directions, allowing staff to more clearly understand the spacing of the thin wafers in three-dimensional space. This enables the development of targeted handling strategies for subsequent thin wafer retrieval, reducing the probability of collisions with adjacent thin wafers during handling. The solution involves obtaining the instantaneous droop distance during each historical handling process and comparing it with the corresponding thin wafer spacing. Risk comparison analysis is conducted to determine the risk level. If the risk is high, correlation analysis is performed based on the adsorption contact area during each historical retrieval process to determine the correlation between the adsorption area and the droop distance. This helps to identify the risk of instantaneous drooping caused by insufficient adsorption contact area in real time, triggering the loading port control system to automatically adjust the suction cup parameters to avoid collision with the wafer vertically below. In addition, combined with the analysis of the uniform distribution of thin wafers in the thin wafer area, basic data for design optimization of the thin wafer loading density in the wafer box is provided, and the thin wafer loading density in the wafer box is optimized in a targeted manner.

[0099] Example 2:

[0100] like Figure 1 - Figure 2 As shown, based on Embodiment 1, the control method for a wafer cassette loading port according to this embodiment of the invention further includes:

[0101] Step 3: If the relationship between the suction area and the droop distance is relatively close, obtain the correlation adjustment coefficient, get the number of suction cups to be adjusted, and distribute them according to the suction cup distribution strategy in multiple historical retrieval processes to obtain the distribution strategy evaluation value and evaluate whether the suction cup distribution strategy is reasonable.

[0102] In some embodiments, the adsorption contact area within each set of correlation analysis data set is divided by the comparison risk degree, and the unit correlation coefficient is output;

[0103] The unit correlation coefficients of all correlation analysis data sets are averaged to output the correlation adjustment coefficient;

[0104] The comparison risk degree threshold is divided by the correlation adjustment coefficient to output the adjusted adsorption area quantity, and the current adsorption area is summed to output the adjusted adsorption area;

[0105] The adjusted adsorption area is divided by the adsorption area corresponding to each suction cup to output the suction cup adjustment quantity;

[0106] The suction cup adjustment quantity is evenly distributed according to the current suction cup adsorption strategy, and the process is as follows:

[0107] A1, on the surface of the thin wafer, the bottom center of each suction cup and the center of the thin wafer surface are extracted, the distance between the bottom center of each suction cup and the center of the thin wafer surface is obtained, and the circumference of the thin wafer surface is divided by the distance to obtain the unit radial distance, and all unit radial distances are averaged to output the radial distance average;

[0108] It should be noted that since there is a direct correlation between the sag risk and the stress of the wafer, specifically, if the contact point between the suction cup and the thin wafer deviates from the center of the thin wafer too far, it is easy to form an eccentric torque around the center of the thin wafer, causing the thin wafer to tilt during the picking process, therefore, the unit radial distance is obtained, which is beneficial to obtain the potential tilt risk of the thin wafer during the picking process from the two-dimensional plane dimension;

[0109] A2, the bottom centers of adjacent suction cups are connected by a straight line, and the bottom centers of adjacent suction cups are respectively connected with the center of the thin wafer surface by a straight line to construct a fitting triangle;

[0110] The distance between the bottom centers of adjacent suction cups is obtained as the side length of the fitting triangle A;

[0111] The distance between the bottom centers of adjacent suction cups and the center of the thin wafer surface is respectively taken as the side length of the fitting triangle B and the side length of the fitting triangle C;

[0112] The side length of the fitting triangle A, the side length of the fitting triangle B and the side length of the fitting triangle C are input into the cosine theorem formula, and the circumferential angle (θ) is divided by the side length to output the unit circumferential angle ;

[0113] Specifically, the formula of the triangle function is:​ wherein, represents the length of the side of the fitting triangle A, represents the length of the side of the fitting triangle B, and represents the length of the side of the fitting triangle C;

[0114] combining the adjacent chuck bottom parts to obtain a chuck arrangement combination, wherein the chuck arrangement combination further comprises a first arranged chuck bottom part and a last arranged chuck bottom part;

[0115] inputting the corresponding unit circumferential angle of the chuck arrangement combination into the Euclidean distance formula in a clockwise manner, and outputting to obtain a circumferential angle difference;

[0116] summing the circumferential angle difference and the radial distance average, and outputting to obtain a distribution strategy evaluation value;

[0117] It can be understood that the meaning represented by the distribution strategy evaluation value is that by combining the radial distance average and the circumferential angle difference, the rationality of the current chuck distribution strategy is quantitatively evaluated. On the one hand, the radial distance average reflects the distance between the center of each chuck bottom part and the center of the thin wafer surface. Since the overall distribution of the chucks deviates far from the center of the thin wafer, it is easy to form an eccentric moment around the center of the thin wafer. Moreover, in actual operation, if the chucks are mainly distributed in the edge region of the thin wafer, and there are fewer chucks in the center region, then during picking, the pulling force of the edge chucks on the thin wafer will cause the thin wafer to rotate around the center, thereby causing tilting. On the other hand, the circumferential angle difference reflects the distribution angle of adjacent chucks in the circumferential direction of the thin wafer. Since the chucks are unevenly distributed in the circumferential direction, the thin wafer is subjected to uneven circumferential forces during picking, thereby affecting the stability of picking and causing the thin wafer to rotate or twist during picking;

[0118] If the distribution strategy evaluation value is greater than the distribution strategy evaluation threshold value, it indicates that the chuck distribution strategy in the multiple historical picking processes has a low matching degree with the current adjusted number of chucks, and there is a high potential tilting risk degree, which is displayed as a low matching signal of the distribution strategy;

[0119] If the distribution strategy evaluation value is less than or equal to the distribution strategy evaluation threshold value, it indicates that the chuck distribution strategy in the multiple historical picking processes has a high matching degree with the current adjusted number of chucks, and there is a low potential tilting risk degree, which is displayed as a high matching signal of the distribution strategy;

[0120] Step four: if the matching degree of the chuck distribution strategy and the adjusted number of chucks is low, adjust the distribution of the chucks according to the adjusted number of chucks, and construct a chuck distribution map;

[0121] In some embodiments, the circumferential angle is calculated by ratio of the number of chuck adjustments, and the average circumferential angle is outputted;

[0122] According to the average circumferential angle, each chuck is placed on the corresponding angle line on the surface of the thin wafer, and the radial distance of each chuck is adjusted, as follows:

[0123] It should be noted that the angle line is a straight line from the center of the thin wafer surface to the edge of the thin wafer surface, with the average circumferential angle as the reference angle, and each angle line corresponds to only one chuck;

[0124] The distribution strategy evaluation threshold is calculated by ratio of the number of chuck adjustments, and the radial adjustment value is outputted, and the unit radial distance is subtracted to obtain the unit radial adjustment amount;

[0125] According to the radial adjustment value and the average circumferential angle, each chuck is placed on the corresponding angle line on the surface of the thin wafer, and a chuck distribution map is constructed;

[0126] The embodiment scheme is: if the correlation between the suction area and the sag distance is relatively close, the correlation adjustment coefficient is obtained, the number of chuck adjustments is obtained, and whether the chuck distribution strategy in the multiple historical taking processes is reasonable is analyzed, if not, the distribution of the chucks is adjusted according to the number of chuck adjustments, and a chuck distribution map is constructed, on the one hand, by adjusting the distance between the chucks and the center of the thin wafer, the probability of the thin wafer tilting in the taking process of the edge chuck is reduced, on the other hand, by adjusting the circumferential angle of the chucks on the thin wafer, the circumferential angle of the chucks on the thin wafer is uniformly distributed, and the stability of the chucks in the taking process of the thin wafer is avoided, and the probability of collision with adjacent thin wafers in the taking process of the thin wafer is reduced.

[0127] Embodiment 3:

[0128] As shown in Figure 3 , the control system of the wafer box loading port of the embodiment of the application comprises:

[0129] The extraction module is constructed: according to the length, width and height in the wafer box, a three-dimensional model of the wafer box is constructed, and the thin wafer area in the three-dimensional model of the wafer box is extracted, the distribution distance of the thin wafers is analyzed, and the thin wafer distance is obtained;

[0130] The correlation analysis module: the instantaneous sag distance in each historical taking process is obtained, and the corresponding thin wafer distance is compared in risk, the comparison risk degree is determined, if the risk degree is high, the correlation analysis is combined with the suction contact area in each historical taking process, and the correlation degree between the suction contact area and the sag distance is determined;

[0131] Adjustment evaluation module: if the correlation between the suction area and the sag distance is close, the correlation adjustment coefficient is obtained, the number of suction disc adjustments is obtained, and whether the suction disc distribution strategy in the historical taking process is reasonable is analyzed;

[0132] Distribution adjustment module: if it is not reasonable, the distribution of the suction disc is adjusted according to the number of suction disc adjustments, and a suction disc distribution diagram is constructed.

[0133] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A method of controlling a wafer cassette load port, the method comprising: The method comprises the following steps: ​ A three-dimensional model of the wafer box is constructed by taking the length of the wafer box as the Y axis, the width of the wafer box as the X axis, and the height of the wafer box as the Z axis, and a thin wafer area in the three-dimensional model of the wafer box is extracted to analyze the distribution interval of the thin wafers and obtain the thin wafer interval; The instantaneous sag distance in each historical taking process is obtained, and the corresponding thin wafer interval is compared to determine the comparison risk degree; if the risk degree is high, the adsorption contact area in each historical taking process is analyzed to determine the correlation between the adsorption contact area and the sag distance; The comparison risk degree is determined as follows: The Z-axis coordinate of the thin wafer after each historical taking on the three-dimensional model of the wafer box is obtained, and the Z-axis coordinate of the thin wafer on the three-dimensional model of the wafer box is subtracted to obtain the absolute value, and the Z-axis length is compared to obtain the instantaneous sag distance; The instantaneous sag distance and the corresponding thin wafer interval are compared to obtain the comparison risk degree; If the correlation between the adsorption contact area and the sag distance is close, the correlation adjustment coefficient is obtained to obtain the number of adjusted suction cups, and whether the suction cup distribution strategy in the historical taking process is reasonable is analyzed; The correlation adjustment coefficient is obtained to obtain the number of adjusted suction cups as follows: The adsorption contact area and the comparison risk degree in each group of correlation analysis data are compared to obtain the unit correlation coefficient; All unit correlation coefficients are averaged to obtain the correlation adjustment coefficient; The comparison risk degree threshold and the correlation adjustment coefficient are compared to obtain the adjusted adsorption contact area, which is summed with the current adsorption contact area to obtain the adjusted adsorption contact area, and the adsorption area of each suction cup is compared to obtain the number of adjusted suction cups; If it is not reasonable, the distribution of the suction cups is adjusted according to the number of adjusted suction cups to construct a suction cup distribution map.

2. The control method of a wafer cassette load port according to claim 1, wherein: The thin wafer interval is obtained as follows: The thin wafer area in the three-dimensional model of the wafer box is extracted, and adjacent thin wafers in the thin wafer area are combined to obtain a plurality of thin wafer combinations; The distance between adjacent thin wafers in each thin wafer combination is obtained as the thin wafer interval.

3. The control method of a wafer cassette load port according to claim 1, wherein: If the risk degree is high, the adsorption contact area in each historical taking process is analyzed as follows: If the comparison risk degree is greater than the comparison risk degree threshold, a high-risk signal is displayed, the area of the bottom of each suction cup is obtained by using the circular area calculation formula, summed, and compared with the surface area of the thin wafer to obtain the adsorption contact area; The adsorption contact area and the comparison risk degree in each historical taking process are taken as a group of correlation analysis data to obtain a plurality of groups of correlation analysis data, the adsorption contact area and the comparison risk degree in each group of correlation analysis data are extracted, and the time sequence corresponding to the historical taking is sorted to obtain the adsorption contact area sequence and the comparison risk sequence; In the comparison risk sequence, adjacent comparison risk degrees are combined to obtain adjacent comparison risk combinations, and the adjacent adsorption contact areas in each adjacent comparison risk combination are subtracted, and the adjacent comparison risk degrees are subtracted to obtain the absolute value to obtain the single-group adsorption difference and the single-group comparison risk difference.

4. The control method of a wafer cassette load port according to claim 3, wherein: The correlation between the suction area and the sag distance is determined as follows: The data of all single group suction differences and single group risk differences are processed by using the Pearson correlation coefficient calculation method to obtain the correlation analysis value. If the correlation analysis value is greater than or equal to the correlation analysis threshold, a correlation close signal is displayed.

5. The method of claim 1, wherein: The process of analyzing whether the suction cup distribution strategy in the historical taking process is reasonable is as follows: On the thin wafer surface, the bottom center of each suction cup and the center of the thin wafer surface are extracted, the distance between the bottom center of each suction cup and the center of the thin wafer surface is obtained, and the ratio calculation is performed with the circumference length of the thin wafer surface to obtain the unit radial distance, and the mean value of all unit radial distances is calculated to output the radial distance mean value; The bottom centers of adjacent suction cups are connected by a straight line, and the bottom centers of adjacent suction cups and the center of the thin wafer surface are connected by a straight line to construct a fitting triangle; The distance between the bottom centers of adjacent suction cups is obtained as the length of side A of the fitting triangle; The distance between the bottom centers of adjacent suction cups and the center of the thin wafer surface is obtained as the length of side B and side C of the fitting triangle, respectively; The length of side A, side B and side C of the fitting triangle are input into the cosine theorem formula, and the ratio calculation is performed with the circumferential angle to output the unit circumferential angle; The sum of the circumferential angle difference and the radial distance mean value is calculated to output the distribution strategy evaluation value, and if the distribution strategy evaluation value is greater than the distribution strategy evaluation threshold, a distribution strategy low matching signal is displayed.

6. The control method of a wafer cassette load port according to claim 1, wherein: The distribution of the suction cups is adjusted according to the number of suction cup adjustments, and the process is as follows: The circumferential angle is divided by the number of suction cup adjustments to output the average circumferential angle; The distribution strategy evaluation threshold is divided by the number of suction cup adjustments to output the adjustment radial value, and the unit radial distance is subtracted to obtain the unit radial adjustment amount.

7. The method of claim 6, wherein: The construction process of the suction cup distribution map is as follows: According to the adjustment radial value and the average circumferential angle, each suction cup is placed on the corresponding angle line on the thin wafer surface to construct a suction cup distribution map.

8. A control system for a wafer cassette load port, the control system comprising: It includes: A construction extraction module: a wafer box inside the length as the Y axis, the wafer box inside the width as the X axis, the wafer box inside the height as the Z axis, construct the wafer box three-dimensional model, and extract the thin wafer area in the wafer box three-dimensional model, analyze the distribution spacing of the thin wafer, and obtain the thin wafer spacing; The correlation analysis module: the instantaneous sag distance in each historical taking process is obtained, and the corresponding thin wafer spacing is compared to determine the comparison risk degree, if the risk degree is high, the correlation analysis is combined with the suction contact area in each historical taking process to determine the correlation between the suction area and the sag distance; The determination process of the comparison risk degree is as follows: The Z-axis coordinate of the thin wafer after each historical taking on the wafer box three-dimensional model is obtained, and the absolute value of the difference between the Z-axis coordinate of the thin wafer and the theoretical Z-axis coordinate of the wafer box three-dimensional model is calculated, and the ratio calculation is performed with the Z-axis length to obtain the instantaneous sag distance; The ratio calculation is performed between the instantaneous sag distance and the corresponding thin wafer spacing to output the comparison risk degree; Adjustment evaluation module: if the correlation between the suction area and the sag distance is close, obtain the correlation adjustment coefficient, get the suction cup adjustment quantity, and analyze whether the suction cup distribution strategy in the historical taking process is reasonable; Obtain the correlation adjustment coefficient to get the suction cup adjustment quantity. The process is as follows: Calculate the ratio of the adsorption contact area in each group of correlation analysis data set to the comparison risk degree, and output the unit correlation coefficient. Calculate the mean value of all unit correlation coefficients, and output the correlation adjustment coefficient. Calculate the ratio of the comparison risk degree threshold value to the correlation adjustment coefficient, output the adjustment suction area quantity, sum the current suction area, output the adjustment suction area, and calculate the ratio of the adjustment suction area to the adsorption area corresponding to each suction cup, and output the suction cup adjustment quantity. Distribution adjustment module: if it is not reasonable, adjust the distribution of the suction cup according to the suction cup adjustment quantity, and construct a suction cup distribution map.

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