Method for generating plasma method for cleaning and method for treating substrate

Abstract

A plasma generation method in a toroidal plasma generator that includes a gas passage having a gas entrance and a gas outlet and forming a circuitous path and a coil wound around a part of the gas passage includes the steps of supplying a mixed gas of an Ar gas and an NF3 gas containing at least 5% of NF3 and igniting plasma by driving the coil with a high-frequency power, wherein the plasma ignition step is conducted under a total pressure of 6.65-66.5 Pa.

Description

TECHNICAL FIELD [0001] The present invention generally relates to fabrication of semiconductor devices and more particularly to a cleaning method and substrate processing method that uses plasma. Further, the present invention related to a plasma generator and particularly to a plasma ignition method. [0002] Plasma generator is used extensively in fabrication of semiconductor devices or liquid crystal display devices. For example, with the use of plasma generator, it becomes possible to carry out film formation processing or etching processing at a low temperature in which there is caused no change of concentration profile of impurity elements formed in a semiconductor substrate. Further, plasma generator is used also for cleaning the interior of processing vessel after conducting a substrate processing therein. BACKGROUND ART [0003]FIG. 1 shows the construction of a typical conventional single-wafer CVD apparatus 10. [0004] Referring to FIG. 1, the single-wafer CVD apparatus 10 inc...

AI Technical Summary

Benefits of technology

[0081] According to the present invention, it becomes possible with a toroidal plasma generator to ignite plasma by a high-frequency power under a total pressure of 6.65-66.5 Pa while supplying a mixed gas of an Ar gas and a NF3 gas containing at least 5% of NF3 and thus it becomes possible to ignite plasma for an Ar / NF3 mixed gas. As a result, it becomes possible to eliminate the purging process of an NF3 gas from a remote plasma source, which has been necessary in single-wafer substrate processing systems whenever there is a need of turning plasma on and off, and it becomes possible to improve the throughput of cleaning or substrate processing significantly. Once the plasma has been ignited, it becomes possible to move from a ignition point of plasma to a processing point where cleaning or etching processing is conducted, without extinguishing the plasma, and efficient plasma process becomes necessary.

[0082] Further, according to the present invention, it becomes possible to ignite plasma with low voltage even in a gas containing a halogen compound, by decreasing the gas pressure at the time of plasma ignition. With this, it becomes possible to avoid occurrence of large voltage overshoot caused by large impedance change occurring at the moment of plasma ignition and associated problems of damaging in the driving power source, electrodes or coils. Further, with the present invention, it becomes possible to carry out the desired cleaning process or etching process efficiently after such ignition of plasma, by increasing the gas pressure to a predetermined process condition while sustaining plasma. Further, according to the present invention, it becomes possible to ignite plasma in the gas containing a halogen compound, and thus, the need of purging the gas containing halogen compound each time plasma is to be ignited is no longer necessary in the process where there is a need of turning on and turning off the plasma frequently, as in the case of single-wafer process, and the throughput of cleaning or substrate processing is improved significantly.

Problems solved by technology

However, when such frequent cleaning processing has been conducted, the cleaning time associated with the cleaning processing causes serious decrease in the throughput of semiconductor production.

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