Impedance Matching Method for Plasma Etching System

Abstract

The invention relates to an impedance matching method of a plasma etching system. The impedance method comprises the steps of providing a plasma etching system, wherein the plasma etching system comprises an impedance matching device, the input end of the impedance matching device is electrically connected with a source power and a bias power supply, the output end of the impedance matching device is electrically connected with a reaction cavity, the end, connected with the source power, of the impedance matching device is electrically connected with one end of a voltage-current detector, and the other end of the voltage-current detector is connected with the source power through a frequency regulation control unit; the source power and the bias power supply simultaneously work under a continuous power mode, and a first matching frequency can be obtained by adjusting the frequency of the source power; the bias power supply is converted into a pulse power mode, and the first matching frequency serves as a benchmark frequency of the source power under a bias power supply pulse opening state, and when the bias power supply is converted to a pulse closing state from the pulse opening state, the benchmark frequency is adopted as the benchmark, so that a second matching frequency can be obtained by increasing or reducing the frequency of the source power.

Description

Technical field [0001] The present invention relates to the field of semiconductor technology, in particular to an impedance matching method of a plasma etching system. Background technique [0002] In semiconductor processes, plasma gas-related processes are becoming more and more important in the manufacture of semiconductor devices, such as plasma etching processes, reactive ion etching processes, and so on. [0003] The dual-frequency plasma etching system generally includes an etching chamber, a bias power and a source power. The source power has a higher frequency, such as 13MHZ, 27MHZ or above 60Mhz, for generating in the reaction chamber. While maintaining the plasma, it is used to control the density of the plasma. The frequency of the bias power supply is relatively low, such as a 2Mhz radio frequency power supply, which is used to control the movement direction of the plasma and the energy carried. The bias power supply and the source power supply provide radio frequenc...

AI Technical Summary

Problems solved by technology

In the existing method of adjusting the frequency of the source power to achieve impedance matching, the frequency modulation algorithm of the source power is inefficient and cannot automatically find a suitable matching frequency

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