Quartz wafer resonant frequency and scatter difference statistical method based on wafer differentiation

Abstract

The invention discloses a quartz wafer resonant frequency and scatter difference statistical method based on wafer differentiation. The quartz wafer resonant frequency and scatter difference statistical method based on the wafer differentiation comprises the following steps that a procedure is started, whether this-time sweep frequency sampling is finished or not is judged, if the this-time sweepfrequency sampling is finished, the wafer differentiation and data processing procedures are performed, and after the wafer differentiation and data processing procedures are finished, the procedure of judging whether the continuous circle rotation speed is stable or not is performed; if the this-time sweep frequency sampling is not finished, the procedure of judging whether the continuous circlerotation speed is stable or not is performed; whether the continuous circle rotation speed is stable or not is judged, if the continuous circle rotation speed is stable, whether this-segment timing time in this circle is up or not is further judged; if this-segment timing time in this circle is not up, circle number entering judging is performed; whether this-segment timing time in this circle isup or not is judged, if this-segment timing time in this circle is up, the data processing procedure of this-segment timing time in this circle being up is performed; if this-segment timing time in this circle is not up, the circle number entering judging is performed; whether circle number enters or not is judged, if the circle number enters, the rotating speed stability judgment procedure and the this-circle data end processing procedure are performed, and then the real-time frequency processing procedure is performed; if the circle number does not enter, the real-time frequency processing procedure is performed directly; and whether shutting down is needed or not is judged, if the shutting down is needed, a grinder is shut down, and the procedure is end.

Description

technical field [0001] The invention belongs to the technical field of on-line frequency measurement of wafer grinding, and in particular relates to a statistical method for resonant frequency and dispersion of quartz wafers based on wafer differentiation. Background technique [0002] Resonance frequency and dispersion statistical mechanism and automatic search method are as follows in the prior art: (1) the instantaneous value storage array of resonance frequency is used for storing the instantaneous resonance frequency of wafer every time, and the average value of all data in this array is used for and Target frequency comparison, when reaching the target frequency times exceeds the set value, shut down the grinding machine; (2) The size of the storage array for the instantaneous value of the resonance frequency used to calculate the real-time resonance frequency (average value of the resonance frequency) is a fixed value, and the data storage adopts Stack first-in-first-...

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Problems solved by technology

[0003] The prior art has the following problems: For example, during the automatic search process, the current automatic search method detects that the number of resonant frequencies measured by the specified time is greater than the set value, which means that the automatic search is successful. If there are many interference signals during the automatic search process, there will be When the wrong resonant frequency is automatically searched, when it is close to the target frequency, the automatic search error occurs, and it is easy to overclock.

As another example, in the statistical process of resonant frequency and dispersion, there are the following problems: (1) Due to the influence of interference signals, after each instantaneous resonant frequency is obtained by the waveform matching method, it is considered to be an effective signal after passing simple constraints. If the signal is further processed, it may be obtained by mismeasurement of the interference signal. The mismeasured resonant frequency will cause the average frequency of the entire wafer to deviate from the actual value, resulting in inaccurate shutdown; (2) Due to the compensation of the amount of grinding The reason is that when the resonant frequency is counted, the frequency grinding amount compensation is not performed on the first data in the array, resulting in a certain deviation between the actual value and the average value of the array; there is a time difference between the first data and the new data. The time corresponds to a grinding distance, so it is necessary to compensate the amount of grinding for the data entered first; at the same time, the deviation will vary according to the grinding rate; (3) Due to the influence of the fixed size of the storage array for the instantaneous value of the resonance frequency, during the wafer grinding process The number of resonant frequency measured in each lap is different. Since the size of the storage array for the instantaneous value of the resonant frequency is fixed, the array data cannot represent the frequency information within one lap of a reel, and the average of the array cannot accurately represent the average frequency of the entire reel. ; (4) The instantaneous value storage array of resonance frequency stores the instantaneous value of resonance frequency measured each time, without distinguishing the chips, so the weight of each chip in the array will be different due to the different times of measurement, which will affect the accuracy of shutdown ; (5) The scatter statistical data did not get rid of the false detection signal through the method of chip differentiation, so if the false detection signal participates in the statistics of the scatter value, the scatter statistics will not match the actual situation; (6) The original data of the scatter statistics did not Compensate the amount of grinding, and the dispersion statistics will not match the actual situation

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