A dual quartz crystal film thickness controller and error correction method

Abstract

The invention discloses a dual quartz crystal oscillator film thickness controller and an error correction method. It belongs to the field of film thickness monitoring and includes: a vacuum chamber, an evaporation source in the vacuum chamber, a substrate structure and a dual quartz crystal oscillator structure, and oscillation outside the vacuum chamber. device and control device; the substrate structure contains a substrate as a coating carrier; the dual quartz crystal oscillator structure includes: one or more pairs of quartz crystal oscillators, a first shell fixed on the wall of the vacuum chamber, which faces the evaporation source A first window is provided on one side, and a first turntable is provided inside. Each pair of quartz crystal oscillators is fixed on both sides of the first turntable and is connected through a thermally conductive material; the oscillator is used to send a signal to a pair of quartz crystal oscillators at the first window. The same changing current is passed through to make it vibrate; the control device is used to calculate the real-time film thickness based on the electronic signal generated by the vibration of the quartz crystal oscillator, and control the evaporation power according to the calculation results, and control the rotation of the first turntable. The invention can improve the film thickness measurement accuracy of the quartz crystal oscillator film thickness controller.

Description

technical field [0001] The invention belongs to the field of film thickness monitoring, and more specifically relates to a dual quartz crystal vibration film thickness controller and an error correction method. Background technique [0002] The quartz crystal vibration film thickness controller uses the quartz crystal vibration method to monitor the coating thickness. The sensitivity is very high, up to the order of angstroms. It is currently the only method that can simultaneously control the film thickness and film formation rate, and has been widely used in the field of film thickness monitoring. [0003] The quartz crystal vibration film thickness controller mainly uses two effects of the quartz crystal vibration plate, namely the piezoelectric effect and the mass load effect. Quartz crystal is an ionic crystal. Due to the regular distribution of the crystal lattice, when mechanical deformation (such as stretching or compression) occurs, electric polarization occurs insi...

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Problems solved by technology

[0005] However, during the coating process, as the thickness of the coating increases, the resonant vibration of the quartz crystal oscillator will gradually weaken, and the measured film-forming speed will gradually decrease, while the film-forming speed on the substrate is uniform, so as the coating With the passage of time, the film thickness measurement accuracy of the quartz crystal film thickness meter will gradually decrease; in addition, the sensitivity of the quartz wafer is very high, and the inevitable temperature change during the coating process will also affect its oscillation frequency, thereby affecting the measured film thickness. the accuracy of

In addition, the working life of a quartz wafer is limited. When the coating thickness is too high, the fundamental frequency of the quartz crystal oscillator drops too much, and it cannot work stably, resulting in frequency hopping. If the film layer continues to be deposited at this time, it will appear vibration stop

In order to ensure stable oscillation and high sensitivity, after the film on the crystal is plated to a certain thickness, a new crystal oscillator should be replaced. This process will also reduce the working efficiency of the film thickness meter.

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