Method and system for processing radio-frequency plasma

Abstract

The present application discloses a technology of radio frequency plasma treatment using radio frequency waves of two different frequencies, in which plasma can be sufficiently and stably generated and maintained. The first frequency is used to generate a plasma by inducing a discharge, and the second frequency is used to generate a self-bias voltage on the substrate being processed. The wave of the second frequency is applied with a time lag after the application of the radio frequency wave of the first frequency. The present application also discloses impedance matching techniques in radio frequency plasma processing in which the impedance provided is optimized for inducing discharge and stabilizing the plasma.

Description

technical field [0001] The present invention relates to processes utilizing plasmas generated by radio frequency (RF) waves. In particular, the present invention relates to processes that simultaneously utilize radio frequency waves of different frequencies. Background technique [0002] The process of using plasma generated by the energy of radio frequency waves is very practical in the manufacture of semiconductor devices such as large scale integration (LSI) and display devices such as liquid crystal displays (LCD), and this process is hereinafter referred to as It is called "RF plasma process" or "RF plasma treatment". In such processes, higher frequency radio frequency waves like in very high frequency (VHF), ie 30 MHz to 300 MHz, have been used more often. This point will be described later. [0003] One reason for using higher frequency waves is the need to reduce the pressure in the process. The requirement to reduce the process pressure is closely related to the...

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Problems solved by technology

[0012] However, from the research of the inventors, the fact that the use of two different frequencies, for example in the VHF band and the HF band, brings about some problems that cannot be ignored

Specifically, it poses the problem that the plasma cannot be well maintained because the coupling of the RF energy to the plasma becomes insufficient, and that the plasma becomes unstable in its initial state

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