Plasma processing apparatus and method

Abstract

Disclosed is a plasma processing apparatus and a plasma processing method, by which ions of plasma can be injected uniformly over the whole surface of a substrate to be processed, in a short time. Specifically, when the substrate is processed in a reaction container, the gas pressure inside the reaction container is increased. Alternatively, the distance between a plasma processing portion and the substrate is enlarged, or the substrate is temporally moved outwardly of the reaction container. As a further alternative, a shutter is disposed between the plasma producing zone and the substrate. With this procedure, incidence of ions of the plasma upon the substrate can be substantially intercepted for a predetermined time period from the start of plasma production.

Description

FIELD OF THE INVENTION AND RELATED ART [0001] This invention relates to plasma processing apparatus and method for injecting ions of plasma into a whole surface to be processed, uniformly and in a short time. Such apparatus and method will be particularly suitably usable in production of microdevices having an extraordinarily fine pattern, such as semiconductor chip (e.g. VLSI: very large scaled integrated circuit), LCD (liquid crystal display), CCD (charge coupled device), thin-film magnetic head, micromachine, etc. [0002] In recent attempts to meet further increases in density of semiconductor devices, silicon oxynitride films are used as a gate insulating film of a thickness not greater than 3 nm. The silicon oxynitride film is produced by introducing nitrogen into a silicon oxide film. The silicon oxynitride film has high relative dielectric constant, and also it has a function for reducing leakage current or boron diffusion from a gate electrode. Because of these superior chara...

AI Technical Summary

Benefits of technology

The present invention provides a plasma processing apparatus and method that improves processing uniformity and reduces inconveniences. The improvement involves intercepting the incidence of ions of the plasma onto the substrate for a predetermined time period, which allows for stabilization of the plasma distribution and ensures nitriding uniformity of the substrate. This can be achieved by controlling the gas pressure inside the reaction container, using shutter means or stage means, or by controlling the microwave surface-wave plasma density. The invention allows for high-density plasma processing with uniform ion density over the whole surface of the substrate.

Problems solved by technology

Since the nitrogen concentration at the interface between silicon and silicon oxide film is high, the device characteristic will not be good.

Further, because of high temperature treatment of a wafer at around 800 to 1000° C., substances other than nitrogen will be diffused together, and this will make the device characteristic worse.

Furthermore, there is another problem that the process time is quite long.

According to the remote plasma processing method, however, since necessary nitrogen active species will be reduced together with nitrogen ions inside the plasma, it is not easy to obtain sufficient nitrogen active species and thus the processing time is very long.

Furthermore, there is another problem that, since the nitrogen concentration distribution in depth direction inside the silicon oxide film decreases sharply with the depth, it is difficult to assure an increased nitrogen surface concentration.

According to this plasma processing method, however, there is a possibility that, within a very little time till the localized plasma spreads over the whole surface of a dielectric material window, ions in that plasma locally nitrides the silicon oxide film to thereby degrade the nitrogen uniformness of the silicon oxide film.

Furthermore, since the silicon oxide film is processed by high density plasma, the time required for producing a silicon oxynitride film of desired nitrogen concentration is short so that the little time described above can not be disregarded.

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