Wafer grinding and polishing adjustment method based on pressure sensing

Abstract

The invention relates to the technical field of wafer processing, and particularly discloses a wafer grinding and polishing processing adjusting method based on pressure sensing, and the method comprises the steps: S1, measuring the current initial thickness of a to-be-processed wafer, determining the target thickness of the to-be-processed wafer, and bonding the wafer to a substrate, polishing states of the wafer at different time points can be determined by collecting state parameter data of polishing equipment and the wafer in polishing operation in real time for analysis, when a polishing disc is seriously abraded, the feeding distance of a polishing push rod can be adjusted in real time according to the polishing states of the wafer at different time points, and the polishing efficiency is improved. Therefore, good contact between the polishing disc and the wafer in the whole polishing process is guaranteed, the polishing efficiency and effect are guaranteed, whether the polishing disc needs to be replaced or not can be judged by analyzing the state of the machined wafer, the situation that the polishing disc which is seriously abraded increases the load of polishing equipment is avoided, and the polishing efficiency is improved. And wear and aging of the equipment are accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of wafer processing, and in particular to a wafer grinding and polishing processing adjustment method based on pressure sensing. Background Art

[0002] A wafer refers to a silicon chip used to make silicon semiconductor circuits. Its raw material is silicon. Before the wafer is put into use, the surface of the wafer to be processed needs to be ground and polished according to a preset control strategy to ensure that the wafer has good flatness and smoothness after processing to meet the requirements of subsequent processes.

[0003] The conventional adjustment method for wafer grinding and polishing processing is usually to first fix the wafer on the grinding table, and then adjust the initial feed distance of the grinding push rod according to the preset control strategy. After that, the wafer can be ground. During the grinding process, the grinding push rod will gradually move toward the wafer through the preset feed distance to ensure that the grinding disc can have good contact with the wafer, thereby ensuring the grinding and polishing effect of the wafer.

[0004] In the prior art, during the grinding process, the grinding push rod gradually moves toward the wafer through a preset feed distance. However, the grinding surface of the grinding disc will wear during use, resulting in reduced grinding efficiency. If the feed of the grinding push rod is always controlled according to the established feed distance, when the grinding disc is highly worn, the pressure applied by the grinding disc on the wafer will gradually decrease, thereby affecting the grinding efficiency and grinding effect. Summary of the invention

[0005] The purpose of the present invention is to provide a wafer grinding and polishing adjustment method based on pressure sensing to solve the following technical problems:

[0006] How to dynamically adjust the distance of the grinding push rod in real time to ensure grinding efficiency.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] A wafer grinding and polishing process adjustment method based on pressure sensing, the method comprising:

[0009] S1: measuring the current initial thickness of the wafer to be processed, determining the target thickness of the wafer to be processed, and bonding the wafer to the substrate;

[0010] S2: adjusting the initial feed distance of the grinding push rod according to the preset control strategy so that the pressure between the grinding disc and the wafer to be processed reaches the value corresponding to the preset control strategy;

[0011] S3: Perform grinding operation according to the grinding disc speed in the preset strategy, collect and analyze the state parameter data of the grinding equipment and the wafer in real time, determine the grinding state of the wafer at different time points, and adjust the feeding distance of the grinding push rod in real time according to the grinding state of the wafer at different time points;

[0012] S4: When the wafer is polished to the target thickness, the wafer status after processing is analyzed to determine whether the polishing disc needs to be replaced. If not, the wafer polishing operation is completed. If yes, proceed to step S5:

[0013] S5: When it is determined that the grinding disc needs to be replaced, a warning is issued and the wafer grinding operation is automatically stopped to wait for the grinding disc to be replaced.

[0014] Furthermore, the process of adjusting the feed distance of the grinding push rod in S3 includes:

[0015] S31: firstly, collecting the state data of the wafer during polishing, including the surface temperature, thickness and color depth of the polishing slurry of the wafer during polishing;

[0016] S32: calculating the polishing state influence coefficient of the wafer at different time points by collecting the pressure change between the polishing disk and the wafer to be processed and the rotation speed change of the polishing disk and combining the data collected in S31;

[0017] S33: by comparing the polishing state influence coefficient of the wafer at different time points with the preset influence coefficient, and judging whether it is necessary to adjust the feeding distance of the polishing push rod according to the comparison result, if not, no operation is performed, if yes, proceed to step S34;

[0018] S34: The feeding distance of the polishing push rod is adjusted by combining the polishing state influence coefficient of the wafer at different time points and the driving motor equipment parameters of the polishing push rod.

[0019] Furthermore, the process of calculating the polishing state influence coefficient of the wafer at different time points in S32 includes:

[0020] By formula Calculate the surface temperature dispersion coefficient of the wafer from the beginning of polishing to the i-th time point ;

[0021] Among them, i is the data collection at a fixed time interval since the start of wafer polishing, n is the total number of data collections from the start of wafer polishing to the i-th time point, is the surface temperature of the wafer at the i-th time point after the start of polishing, For all The average value of is the proportionality coefficient, which is set according to empirical fitting. is the room temperature at the i-th time point after the wafer starts polishing, is the preset indoor temperature. is the indoor humidity at the i-th time point after the wafer starts polishing, The preset indoor humidity.

[0022] Furthermore, the process of calculating the polishing state influence coefficient of the wafer at different time points in S32 also includes:

[0023] The real-time speed data of the grinding disc is obtained through real-time monitoring, and the real-time change curve of the grinding disc speed is established. ;

[0024] By formula Calculate the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing ;

[0025] in, is the pressure value between the wafer and the polishing disc at the i-th time point since the start of polishing, is the preset pressure value, is the polishing thickness of the wafer at the i-th time point since the start of polishing, is the preset grinding thickness, is the error influence function, is the color depth of the polishing slurry at the i-th time since the wafer started polishing, is the preset grinding slurry color depth, for The standard value of To define a function, if , then let , otherwise, let , The time point when the first data is collected after the wafer starts polishing. is the time point of the i-th data collection after the wafer starts polishing.

[0026] Furthermore, the comparison process in S33 includes:

[0027] By calculating the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing The preset grinding state influence coefficient threshold Make a comparison;

[0028] like , it is judged that the current grinding state has a high impact, the grinding quality is reduced, and the feeding distance of the grinding push rod needs to be adjusted;

[0029] like , it is judged that the current grinding state has low impact and high grinding quality, and there is no need to adjust the feed distance of the grinding push rod.

[0030] Furthermore, the process of adjusting the feed distance of the grinding push rod in S34 includes:

[0031] By formula Calculate the adjusted grinding push rod feed distance of the wafer at the i-th time point since the start of grinding ;

[0032] in, The preset feed distance for grinding the push rod at the i-th time point, is the voltage value of the grinding push rod drive motor at the i-th time point, For all The standard value of is the current value of the grinding push rod driving motor at the i-th time point, is the preset current value, To adjust the coefficient comparison table function, according to the empirical data The influence of the range of values ​​on the grinding push rod feed distance is obtained based on the test.

[0033] Furthermore, the process of determining whether the grinding disc needs to be replaced in S4 includes:

[0034] By formula Calculate the mass loss coefficient of the finished wafer ;

[0035] in, The flatness of the wafer after polishing. For the preset flatness, The smoothness of the wafer after polishing. is the preset smoothness, is the thickness of the wafer after grinding, is the preset thickness, for The standard value of The total polishing time for the wafer is is the preset polishing time, and m is the total number of data collection times from the start to the end of wafer polishing.

[0036] Furthermore, the process of determining whether the grinding disc needs to be replaced in S4 also includes:

[0037] By adjusting the wafer polishing state influence coefficient The preset grinding state influence coefficient threshold Make a comparison;

[0038] like , it is judged that the quality loss coefficient of the finished wafer is small, which means that the state of the wafer polishing process and the polishing effect are good, and there is no need to replace the polishing disc;

[0039] like , it is judged that the quality loss coefficient of the finished wafer is large, which means that the state of the wafer polishing process and the polishing effect are poor, and the polishing disc needs to be replaced.

[0040] Beneficial effects of the present invention:

[0041] (1) The present invention can determine the polishing status of the wafer at different time points by collecting and analyzing the status parameter data of the polishing equipment and the wafer during the polishing operation in real time. When the polishing disc is severely worn, the feed distance of the polishing push rod can be adjusted in real time according to the polishing status of the wafer at different time points, thereby ensuring that the polishing disc and the wafer have good contact throughout the entire polishing process and ensuring the efficiency and effect of polishing. In addition, by analyzing the status of the wafer after processing, it can be determined whether the polishing disc needs to be replaced, thereby avoiding a severely worn polishing disc from increasing the load on the polishing equipment and accelerating the wear and aging of the equipment.

[0042] (2) The present invention can calculate the polishing state influence coefficient of the wafer at different time points by combining the state data of the wafer during polishing with the pressure change between the polishing disk and the wafer to be processed and the rotation speed change parameters of the polishing disk. The data reflects the polishing state of the wafer at different time points. Therefore, by comparing the polishing state influence coefficient of the wafer at different time points with the preset influence coefficient, it is possible to judge whether it is necessary to adjust the feed distance of the polishing push rod, and timely adjust the feed distance of the polishing push rod based on the data, thereby ensuring that the polishing disk applies sufficient pressure to the wafer and improving the polishing efficiency and effect.

[0043] (3) The present invention combines the wafer status data during the polishing operation, the data information of the polishing equipment, and the surface temperature dispersion coefficient of the wafer from the beginning of polishing to the i-th time point The diversified data improves the accuracy and reliability of the calculation results of the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing, and provides accurate and reliable data support for the subsequent adjustment of the feed distance of the polishing push rod, ensuring the accuracy of the adjustment results of the polishing push rod feed distance.

[0044] (4) The present invention calculates the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing. The preset grinding state influence coefficient threshold Through this comparison method, the grinding quality can be judged in combination with the influence of the grinding state at the current time point. When judging the grinding quality, it means that if the feed of the grinding push rod is still controlled according to the established feed distance, the grinding efficiency and grinding effect will be greatly reduced. The feed distance of the grinding push rod needs to be adjusted, thereby realizing real-time dynamic adjustment of the distance of the grinding push rod to ensure the grinding efficiency.

[0045] (5) The present invention reduces the influence coefficient of wafer polishing state by The preset grinding state influence coefficient threshold Through this comparison method, the state of the wafer polishing process and the polishing effect can be analyzed and judged according to the size of the mass loss coefficient of the finished wafer, and a decision can be made based on the analysis results whether the polishing disc needs to be replaced, thereby avoiding the situation where the polishing efficiency is reduced due to excessive wear of the polishing disc and improving the polishing effect of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described below in conjunction with the accompanying drawings.

[0047] Figure 1 It is a flow chart of a wafer grinding and polishing processing adjustment method based on pressure sensing in the present invention;

[0048] Figure 2 It is a flow chart of the process of adjusting the feed distance of the grinding push rod in the present invention. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] See also Figure 1 As shown, in one embodiment, the present application provides a wafer grinding and polishing process adjustment method based on pressure sensing, the method comprising:

[0051] S1: measuring the current initial thickness of the wafer to be processed, determining the target thickness of the wafer to be processed, and bonding the wafer to the substrate;

[0052] S2: adjusting the initial feed distance of the grinding push rod according to the preset control strategy so that the pressure between the grinding disc and the wafer to be processed reaches the value corresponding to the preset control strategy;

[0053] S3: Perform grinding operation according to the grinding disc speed in the preset strategy, collect and analyze the state parameter data of the grinding equipment and the wafer in real time, determine the grinding state of the wafer at different time points, and adjust the feeding distance of the grinding push rod in real time according to the grinding state of the wafer at different time points;

[0054] S4: When the wafer is polished to the target thickness, the wafer status after processing is analyzed to determine whether the polishing disc needs to be replaced. If not, the wafer polishing operation is completed. If yes, proceed to step S5:

[0055] S5: When it is determined that the grinding disc needs to be replaced, a warning is issued and the wafer grinding operation is automatically stopped to wait for the grinding disc to be replaced;

[0056] Through the above technical scheme, this embodiment provides a wafer grinding and polishing adjustment method based on pressure sensing, firstly, the current initial thickness of the wafer to be processed is measured, the target thickness of the wafer to be processed is determined, and the wafer is bonded to the substrate, and then the initial feed distance of the grinding push rod is adjusted according to the preset control strategy, so that the pressure between the grinding disc and the wafer to be processed reaches the size corresponding to the preset control strategy, and then the grinding operation can be performed according to the grinding disc speed in the preset strategy, and the state parameter data of the grinding equipment and the wafer are collected in real time for analysis to determine the grinding state of the wafer at different time points, and the feed distance of the grinding push rod is adjusted in real time according to the grinding state of the wafer at different time points; when the wafer is polished to the target thickness, the state of the wafer after the processing is completed is analyzed to determine whether the grinding disc needs to be replaced, if it is determined that the grinding disc does not need to be replaced, the wafer grinding operation is completed directly, if it is determined that the grinding disc needs to be replaced, a warning is issued, and the wafer grinding operation is automatically stopped, waiting for the grinding disc to be replaced;

[0057] Through such a setting, this embodiment can determine the polishing status of the wafer at different time points by real-time collection of status parameter data of the polishing equipment and the wafer during the polishing operation for analysis. When the polishing disc is severely worn, the feed distance of the polishing push rod can be adjusted in real time according to the polishing status of the wafer at different time points, thereby ensuring good contact between the polishing disc and the wafer during the entire polishing process, ensuring the efficiency and effect of polishing, and by analyzing the status of the wafer after processing, it can be determined whether the polishing disc needs to be replaced, thereby avoiding severely worn polishing discs that increase the load on the polishing equipment and accelerate the wear and aging of the equipment.

[0058] See also Figure 2 As shown, the process of adjusting the feed distance of the grinding push rod in S3 includes:

[0059] S31: firstly, collecting the state data of the wafer during polishing, including the surface temperature, thickness and color depth of the polishing slurry of the wafer during polishing;

[0060] S32: calculating the polishing state influence coefficient of the wafer at different time points by collecting the pressure change between the polishing disk and the wafer to be processed and the rotation speed change of the polishing disk and combining with the data collected in S31;

[0061] S33: by comparing the polishing state influence coefficient of the wafer at different time points with the preset influence coefficient, and judging whether it is necessary to adjust the feeding distance of the polishing push rod according to the comparison result, if not, no operation is performed, if yes, proceed to step S34;

[0062] S34: adjusting the feeding distance of the polishing push rod by combining the polishing state influence coefficient of the wafer at different time points and the driving motor equipment parameters of the polishing push rod;

[0063] Through the above technical scheme, this embodiment provides a process for adjusting the feed distance of the grinding push rod. First, the state data of the wafer during grinding is collected, including the surface temperature, thickness and grinding slurry color depth of the wafer during the grinding process. Then, the pressure change between the grinding disk and the wafer to be processed and the rotation speed change of the grinding disk are collected, and the grinding state influence coefficient of the wafer at different time points is calculated in combination with the state data of the wafer during grinding. Then, the grinding state influence coefficient of the wafer at different time points is compared with the preset influence coefficient, and it is judged whether the feed distance of the grinding push rod needs to be adjusted according to the comparison result. When it is judged that the feed distance of the grinding push rod needs to be adjusted, the feed distance of the grinding push rod is adjusted in combination with the grinding state influence coefficient of the wafer at different time points and the driving motor equipment parameters of the grinding push rod;

[0064] Through such a setting, by combining the state data of the wafer during polishing with the pressure change between the polishing disk and the wafer to be processed and the rotation speed change parameters of the polishing disk, the polishing state influence coefficient of the wafer at different time points can be calculated. This data reflects the polishing state of the wafer at different time points. Therefore, by comparing the polishing state influence coefficient of the wafer at different time points with the preset influence coefficient, it is possible to judge whether it is necessary to adjust the feed distance of the polishing push rod, and adjust the feed distance of the polishing push rod in time based on the data, so as to ensure that the polishing disk applies sufficient pressure on the wafer and improve the polishing efficiency and effect.

[0065] The process of calculating the polishing state influence coefficient of the wafer at different time points in S32 includes:

[0066] By formula Calculate the surface temperature dispersion coefficient of the wafer from the beginning of polishing to the i-th time point ;

[0067] Among them, i is the data collection at a fixed time interval since the start of wafer polishing, n is the total number of data collections from the start of wafer polishing to the i-th time point, is the surface temperature of the wafer at the i-th time point after the start of polishing, For all The average value of is the proportionality coefficient, which is set according to empirical fitting. is the room temperature at the i-th time point after the wafer starts polishing, is the preset indoor temperature. is the indoor humidity at the i-th time point after the wafer starts polishing, is the preset indoor humidity;

[0068] Through the above technical solution, this embodiment provides the surface temperature dispersion coefficient of the wafer from the beginning of polishing to the i-th time point: , can be obtained through the formula It is obvious that when the difference between the surface temperature data of the wafer at each data collection at a fixed time interval since the start of polishing is greater, and the indoor temperature is higher and the humidity is lower, then the surface temperature dispersion coefficient of the wafer from the start of polishing to the i-th time point is On the contrary, when the difference between the surface temperature data of the wafer at each data collection at a fixed time interval since the start of polishing is smaller, and the lower the indoor temperature and the higher the humidity, the surface temperature dispersion coefficient of the wafer from the start of polishing to the i-th time point is The smaller it is;

[0069] By eliminating the influence of indoor temperature and humidity, the greater the difference in surface temperature data of the wafer at each data collection at a fixed time interval since the start of polishing, it means that the pressure applied by the polishing disc on the wafer is continuously changing, which means that there is a certain amount of wear on the polishing disc. Through this calculation method, the subsequent adjustment of the feed distance of the polishing push rod can be supported by diversified data, thereby improving the accuracy and reliability of the adjustment results, ensuring that after the polishing push rod adjustment is completed, the polishing disc can apply sufficient pressure on the wafer to ensure the polishing effect and efficiency.

[0070] The process of calculating the polishing state influence coefficient of the wafer at different time points in S32 also includes:

[0071] The real-time speed data of the grinding disc is obtained through real-time monitoring, and the real-time change curve of the grinding disc speed is established. ;

[0072] By formula Calculate the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing ;

[0073] in, is the pressure value between the wafer and the polishing disc at the i-th time point since the start of polishing, is the preset pressure value, is the polishing thickness of the wafer at the i-th time point since the start of polishing, is the preset grinding thickness, is the error influence function, is the color depth of the polishing slurry at the i-th time since the wafer started polishing, is the preset grinding slurry color depth, for The standard value can be selected and set according to the allowable error in the empirical data. To define a function, if , then let , otherwise, let , The time point when the first data is collected after the wafer starts polishing. is the time point of the i-th data collection after the wafer starts polishing;

[0074] Through the above technical solution, this embodiment provides the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing: , can be obtained by formula Calculated, where the formula The rotation speed change of the wafer between the time point of the first data collection after the start of polishing and the time point of the i-th data collection can be calculated. Obviously, when the rotation speed change is larger, and the polishing thickness, grinding slurry color depth and pressure value between the wafer and the polishing disk at the i-th time point since the start of polishing are smaller, then the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing is larger, indicating that the polishing state of the wafer at the current time point is more affected, and the polishing effect is poor. On the contrary, when the rotation speed change is smaller, and the polishing thickness, grinding slurry color depth and pressure value between the wafer and the polishing disk at the i-th time point since the start of polishing are closer to the preset value, then the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing is smaller, indicating that the polishing state of the wafer at the current time point is less affected, and the polishing effect is good.

[0075] That is because when the polishing thickness, slurry color depth and pressure value between the wafer and the polishing disc at the i-th time point since the start of polishing are smaller, it means that at this time point, the bonding effect between the polishing disc and the wafer becomes worse, which will cause the polishing thickness to be less than the preset thickness, and less dust will cause the slurry color to be lighter, and the pressure value between the wafer and the polishing disc to be less than the preset value, which means that if the feed of the polishing push rod is still controlled according to the established feed distance at this time, the polishing efficiency and polishing effect will be greatly reduced, and the feed distance of the polishing push rod needs to be adjusted;

[0076] Through this calculation method, by combining the state data of the wafer during the polishing operation, the data information of the polishing equipment, and the surface temperature dispersion coefficient of the wafer from the beginning of polishing to the i-th time point, The diversified data improves the accuracy and reliability of the calculation results of the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing, and provides accurate and reliable data support for the subsequent adjustment of the feed distance of the polishing push rod, ensuring the accuracy of the adjustment results of the polishing push rod feed distance.

[0077] The comparison process in S33 includes:

[0078] By calculating the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing Compare with the preset grinding state influence coefficient threshold ;

[0079] like , it is judged that the current grinding state has a high impact, the grinding quality is reduced, and the feeding distance of the grinding push rod needs to be adjusted;

[0080] like , it is judged that the current grinding state has low impact and high grinding quality, and there is no need to adjust the feeding distance of the grinding push rod;

[0081] Through the above technical solution, this embodiment calculates the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing The preset grinding state influence coefficient threshold Through this comparison method, the grinding quality can be judged in combination with the influence of the grinding state at the current time point. When judging the grinding quality, it means that if the feed of the grinding push rod is still controlled according to the established feed distance, the grinding efficiency and grinding effect will be greatly reduced. The feed distance of the grinding push rod needs to be adjusted, thereby realizing real-time dynamic adjustment of the distance of the grinding push rod to ensure the grinding efficiency.

[0082] The process of adjusting the feeding distance of the grinding push rod in S34 includes:

[0083] By formula Calculate the adjusted grinding push rod feed distance of the wafer at the i-th time point since the start of grinding ;

[0084] in, The preset feed distance for grinding the push rod at the i-th time point, is the voltage value of the grinding push rod drive motor at the i-th time point, For all The standard value of is the current value of the grinding push rod driving motor at the i-th time point, is the preset current value, To adjust the coefficient comparison table function, according to the empirical data The influence of the range of values ​​on the grinding push rod feed distance is obtained based on the test;

[0085] Through the above technical solution, this embodiment provides the grinding push rod feed distance adjusted from the i-th time point of the start of grinding. Through this calculation method, after combining the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing and the voltage and current data of the polishing push rod driving motor, it is possible to provide diversified data support for the calculation results of the feed distance of the polishing push rod after adjustment at different time points, thereby improving the accuracy of the calculation results, ensuring real-time adjustment of the feed distance of the polishing push rod, while improving the accuracy and reliability of the feed distance adjustment, and ensuring the polishing efficiency and polishing effect.

[0086] The process of determining whether the grinding disc needs to be replaced in S4 includes:

[0087] By formula Calculate the mass loss coefficient of the finished wafer ;

[0088] in, The flatness of the wafer after polishing. For the preset flatness, The smoothness of the wafer after polishing. is the preset smoothness, is the thickness of the wafer after grinding, is the preset thickness, for The standard value of The total polishing time for the wafer is is the preset polishing time, m is the total number of data collection times from the start to the end of polishing;

[0089] Through the above technical solution, this implementation provides the quality loss coefficient of the finished wafer , can be obtained by formula It is calculated that, obviously, when the flatness and smoothness of the wafer after grinding are higher, the thickness is less different from the preset value, and the grinding time and the average feed distance adjusted by the grinding push rod during the grinding operation are shorter, then the mass loss coefficient of the finished wafer is lower, indicating that the quality of the finished wafer is higher, and the wear of the grinding disc is lower, and it does not need to be replaced. On the contrary, when the flatness and smoothness of the wafer after grinding are higher, the thickness is more different from the preset value, and the grinding time and the average feed distance adjusted by the grinding push rod during the grinding operation are longer, then the mass loss coefficient of the finished wafer is higher, indicating that the quality of the finished wafer is lower, and the wear of the grinding disc is higher, and it needs to be replaced.

[0090] The process of determining whether the grinding disc needs to be replaced in S4 also includes:

[0091] By adjusting the wafer polishing state influence coefficient The preset grinding state influence coefficient threshold Make a comparison;

[0092] like , it is judged that the quality loss coefficient of the finished wafer is small, which means that the state of the wafer polishing process and the polishing effect are good, and there is no need to replace the polishing disc;

[0093] like , it is judged that the quality loss coefficient of the finished wafer is large, which means that the state of the wafer grinding process and the grinding effect are poor, and the grinding disc needs to be replaced;

[0094] Through the above technical solution, this embodiment adjusts the wafer polishing state influence coefficient The preset grinding state influence coefficient threshold Through this comparison method, the state of the wafer polishing process and the polishing effect can be analyzed and judged according to the size of the mass loss coefficient of the finished wafer, and a decision can be made based on the analysis results whether the polishing disc needs to be replaced, thereby avoiding the situation where the polishing efficiency is reduced due to excessive wear of the polishing disc and improving the polishing effect of the wafer.

[0095] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A wafer grinding and polishing adjustment method based on pressure sensing, characterized in that: The method comprises: S1: measuring the current initial thickness of the wafer to be processed, determining the target thickness of the wafer to be processed, and bonding the wafer to the substrate; S2: adjusting the initial feed distance of the grinding push rod according to the preset control strategy so that the pressure between the grinding disc and the wafer to be processed reaches the value corresponding to the preset control strategy; S3: Perform grinding operation according to the grinding disc speed in the preset strategy, collect and analyze the state parameter data of the grinding equipment and the wafer in real time, determine the grinding state of the wafer at different time points, and adjust the feeding distance of the grinding push rod in real time according to the grinding state of the wafer at different time points; S4: When the wafer is polished to the target thickness, the wafer status after processing is analyzed to determine whether the polishing disc needs to be replaced. If not, the wafer polishing operation is completed. If yes, proceed to step S5: S5: When it is determined that the grinding disc needs to be replaced, a warning is issued and the wafer grinding operation is automatically stopped to wait for the grinding disc to be replaced.

2. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 1 is characterized in that: The process of adjusting the feed distance of the grinding push rod in S3 includes: S31: firstly, collecting the state data of the wafer during polishing, including the surface temperature, thickness and color depth of the polishing slurry of the wafer during polishing; S32: calculating the polishing state influence coefficient of the wafer at different time points by collecting the pressure change between the polishing disk and the wafer to be processed and the rotation speed change of the polishing disk and combining the data collected in S31; S33: by comparing the polishing state influence coefficient of the wafer at different time points with the preset influence coefficient, and judging whether it is necessary to adjust the feeding distance of the polishing push rod according to the comparison result, if not, no operation is performed, if yes, proceed to step S34; S34: The feeding distance of the polishing push rod is adjusted by combining the polishing state influence coefficient of the wafer at different time points and the driving motor equipment parameters of the polishing push rod.

3. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 2 is characterized in that: The process of calculating the polishing state influence coefficient of the wafer at different time points in S32 includes: By formula Calculate the surface temperature dispersion coefficient of the wafer from the beginning of polishing to the i-th time point ; Among them, i is the data collection at a fixed time interval since the start of wafer polishing, n is the total number of data collections from the start of wafer polishing to the i-th time point, is the surface temperature of the wafer at the i-th time point after the start of polishing, For all The average value of is the proportionality coefficient, which is set according to empirical fitting. is the room temperature at the i-th time point after the wafer starts polishing, is the preset indoor temperature. is the indoor humidity at the i-th time point after the wafer starts polishing, The preset indoor humidity.

4. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 3 is characterized in that: The process of calculating the polishing state influence coefficient of the wafer at different time points in S32 also includes: The real-time speed data of the grinding disc is obtained through real-time monitoring, and the real-time change curve of the grinding disc speed is established. ; By formula Calculate the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing ; in, is the pressure value between the wafer and the polishing disc at the i-th time point since the start of polishing, is the preset pressure value, is the polishing thickness of the wafer at the i-th time point since the start of polishing, is the preset grinding thickness, is the error influence function, is the color depth of the polishing slurry at the i-th time since the wafer started polishing, is the preset grinding slurry color depth, for The standard value of To define a function, if , then let , otherwise, let , The time point when the first data is collected after the wafer starts polishing. is the time point of the i-th data collection after the wafer starts polishing.

5. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 4 is characterized in that: The comparison process in S33 includes: By calculating the polishing state influence coefficient of the wafer at the i-th time point since the start of polishing The preset grinding state influence coefficient threshold Make a comparison; like , it is judged that the current grinding state has a high impact, the grinding quality is reduced, and the feeding distance of the grinding push rod needs to be adjusted; like , it is judged that the current grinding state has low impact and high grinding quality, and there is no need to adjust the feed distance of the grinding push rod.

6. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 5 is characterized in that: The process of adjusting the feeding distance of the grinding push rod in S34 includes: By formula Calculate the adjusted grinding push rod feed distance of the wafer at the i-th time point since the start of grinding ; in, The preset feed distance for grinding the push rod at the i-th time point, is the voltage value of the grinding push rod drive motor at the i-th time point, For all The standard value of is the current value of the grinding push rod driving motor at the i-th time point, is the preset current value, To adjust the coefficient comparison table function, according to the empirical data The influence of the range of values ​​on the grinding push rod feed distance is obtained based on the test.

7. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 6 is characterized in that: The process of determining whether the grinding disc needs to be replaced in S4 includes: By formula Calculate the mass loss coefficient of the finished wafer ; in, The flatness of the wafer after polishing. For the preset flatness, The smoothness of the wafer after polishing. is the preset smoothness, is the thickness of the wafer after grinding, is the preset thickness, for The standard value of The total polishing time for the wafer is is the preset polishing time, and m is the total number of data collection times from the start to the end of wafer polishing.

8. The wafer grinding and polishing adjustment method based on pressure sensing according to claim 7 is characterized in that: The process of determining whether the grinding disc needs to be replaced in S4 also includes: By adjusting the wafer polishing state influence coefficient The preset grinding state influence coefficient threshold Make a comparison; like , it is judged that the quality loss coefficient of the finished wafer is small, which means that the state of the wafer polishing process and the polishing effect are good, and there is no need to replace the polishing disc; like , it is judged that the quality loss coefficient of the finished wafer is large, which means that the state of the wafer polishing process and the polishing effect are poor, and the polishing disc needs to be replaced.

Images