Substrate processing method

Abstract

A substrate processing apparatus capable of improving a processing controllability in an etching process is provided. The substrate processing apparatus (10) includes a depressurized processing room (11); a susceptor (12) that is provided in the processing room (11) and configured to mount a wafer (W) thereon; a HF high frequency power supply (18) configured to apply a high frequency voltage for plasma generation to the susceptor (12); a LF high frequency power supply (20) configured to apply a high frequency voltage for a bias voltage generation to the susceptor (12); and a DC voltage applying unit (23) configured to apply a DC voltage of a rectangle-shaped wave to the susceptor (12).

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of Japanese Patent Application No. 2011-079733 filed on Mar. 31, 2011, and U.S. Provisional Application Ser. No. 61 / 477,634 on Apr. 21, 2011, the entire disclosures of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present disclosure relates to a substrate processing method for performing a certain process on a substrate by using plasma.BACKGROUND OF THE INVENTION[0003]A substrate processing apparatus performs a certain plasma process on a semiconductor wafer (hereinafter, referred to as simply a “wafer”) serving as a substrate by using plasma. The substrate processing apparatus includes a depressurized processing chamber; a mounting table provided in the processing chamber; a HF (High Frequency) high frequency power supply configured to be connected to the mounting table and apply a high frequency voltage of a relatively high frequency (hereinafter, referred to as a “HF high ...

AI Technical Summary

Benefits of technology

[0014]In accordance with the illustrative embodiments, a second high frequency power supply applies a high frequency voltage of a relatively low frequency to the mounting table. A DC voltage applying unit applies a DC voltage of a rectangle-shaped wave to the mounting table. If a bias voltage is generated on the mounting table by applying the high frequency voltage of the relatively low frequency to the mounting table, it is possible to obtain an ion energy distribution, formed in a certain range, having a peak of relatively low energy and a peak of relatively high energy. If the bias voltage is generated on the mounting table by applying the DC voltage of the rectangle-shaped wave to the mounting table, the ion energy distribution is locally formed and has only one peak. The intensity of anisotropy and the intensity of isotropy in the etching process vary depending on positions or the number of peaks in the ion energy distribution. Accordingly, by adjusting a ratio of an output value from the second high frequency power supply to an output value from the DC voltage applying unit, the intensity of anisotropy and the intensity of isotropy in the etching process can be controlled. As a result, the processing controllability in the etching process can be improved.

Problems solved by technology

However, etching by ions of relatively low energy is strongly isotropic.

Also, isotropy in etching becomes strong even when anisotropy in the etching is needed.

As a result, a desired shape of a hole or a trench may not be formed by the etching.

That is, when the bias voltage is generated in the susceptor by using the LF high frequency voltage, processing controllability in an etching process is not so good.

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