Online frequency measurement system for quartz wafer polishing and grinding

Abstract

The invention discloses an online frequency measurement system for quartz wafer polishing and grinding, comprising a DDS signal module, a radio frequency power amplification module, a phi network interface circuit module, an impedance matching module, a signal processing module, an MCU control system module and a power module for providing a working voltage for the above modules, wherein the DDS signal module generates a specified frequency range and a sweep frequency velocity according to a specified sweep frequency instruction issued by the MCU control system module, and outputs a sinusoidalsweep frequency signal of the power, power amplification is performed on a resonant signal generated by the DDS signal module via the radio frequency power amplification module, the signal subject tothe power amplification is connected to the phi network interface circuit module, the sinusoidal sweep frequency signal acts on a wafer through a phi network to cause the same to generate mechanicalvibration, meanwhile the mechanical vibration of the wafer generates an alternating electric field, when the external positive sweep frequency signal frequency is a certain particular value, the amplitude is significantly increased, and when a signal with a significantly increased amplitude is generated, an effective signal is captured.

Description

technical field [0001] The invention belongs to the technical field of quartz wafer detection, in particular to an on-line frequency measurement system for quartz wafer polishing. Background technique [0002] In the prior art, the on-line frequency measurement of the quartz chip is mostly through signal acquisition and amplification, then peak detection, amplification and filtering, and DC coupling into the single-chip ADC for DC sampling. Its main disadvantages are: it cannot be measured at low frequencies below 5M, and it cannot be measured on polished wafers. The main reasons are as follows: (1) The original circuit is limited by the hardware and has limited amplification ability and limited noise removal ability, which is not enough to distinguish and analyze the signals entering the low frequency and polishing. (2) Low frequency and polishing signals are inherently small, even if the original system can amplify enough, but because the existing DC component will also b...

AI Technical Summary

Problems solved by technology

Its main disadvantages are: it cannot be measured at low frequencies below 5M, and it cannot be measured on polished wafers.

The main reasons are as follows: (1) The original circuit is limited by the hardware and has limited amplification ability and limited noise removal ability, which is not enough to distinguish and analyze the signals entering the low frequency and polishing

(2) Low-frequency and polishing signals are inherently small. Even if the original system can amplify enough, but because the existing DC component will also be amplified at the same time, it cannot be sampled if it exceeds the ADC voltage range of the single-chip microcomputer.

[0003] At the same time, in the prior art, the online frequency monitor (Auto Lapping Controlsystem-ALC) of TRANSAT Company of the United States conducts online measurement and control of the wafer frequency during the grinding process, and there is a problem of "jumping of frequency measurement values ​​in certain frequency bands", and ALC cannot be measured on polished quartz wafers, which cannot meet the current production environment

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