Film Thickness Control Method Based on Quartz Oscillating Film Thickness Monitor

Abstract

The invention provides a very excellent film thickness control method based on a quartz oscillatory type film thickness monitor. Error correction precision of the method is greatly improved, and film thickness measurement precision is greatly improved. The film thickness control method based on the quartz oscillatory type film thickness monitor comprises using a quartz oscillator for measurement in advance before a film forming step to measure the film thickness of a film of a substrate for measurement at different oscillation frequencies, calculating a ratio of a target film thickness measured by the quartz oscillator for the measurement in advance to an actual film thickness, measured at each of the oscillation frequencies, of the film of the substrate for the measurement, multiplying the film thickness, measured by the quartz oscillator when the film is formed, of the film of the substrate for film forming or a film forming speed by a correction ratio corresponding to the corresponding oscillation frequency in the various correction ratios in the film forming step to correct the film thickness of the film of the substrate for the film forming or the film forming speed and then controlling the film thickenss.

Description

technical field [0001] The present invention relates to a film thickness control method based on a quartz oscillator type film thickness monitor, and relates to a technique for correcting errors between a film thickness measured by a quartz vibrator and an actual film thickness on a substrate. Background technique [0002] In a film-forming device that deposits a film-forming material on a substrate by evaporation or sputtering to form a thin film, a film thickness gauge (film thickness monitor) is used to control (manage) the film thickness and the film-forming speed (Rate: rate). device), among which the quartz oscillation type film thickness monitor using the quartz oscillator method is widely used. [0003] This crystal oscillation type film thickness monitor is provided with a quartz vibrator as a measuring part in the film-forming chamber, and utilizes the phenomenon that the resonant vibration changes according to the change in mass when the film-forming material is a...

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Problems solved by technology

[0007] However, in the above calibration method, it is necessary to arrange a calibration crystal vibrator different from the crystal vibrator in parallel, and it is necessary to open the interrupter one by one in the middle of the measurement to perform conversion correction based on the measurement with the calibration crystal vibrator. In addition, this conversion correction is only based on The correction is based on the measurement of the quartz vibrator, not the actual thickness of the thin film on the substrate, and although there is not as much thin film deposited on the quartz vibrator for the calibration as the quartz vibrator used for measurement, the film-forming material is gradually deposited. , the film thickness will still gradually increase, so the correction accuracy of the correction error is poor, and it cannot be said that the measurement accuracy of the film thickness of the substrate has been sufficiently improved.

[0008] In addition, in Patent Document 2 (Japanese Unexamined Patent Publication No. 8-82517), a method of actually measuring and correcting the film thickness of the thin film of the substrate is disclosed, but it is only for a state with a high oscillation frequency and a state with a low oscillation frequency. The actual film thickness is measured and the optimal correction coefficient is calculated by the least square method. Therefore, the two points are only corrected by a fixed value based on the calculation result, and the error correction accuracy is still low. The film thickness of the substrate The measurement accuracy is not enough

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