METHOD FOR SHAPING RESIST PATTERN

PROBLEM TO BE SOLVED: To prevent the formation of a oxide film on the surface of GaAs by shaping a resist pattern by performing plasma treatment using sulfur hexafluoride. SOLUTION: A resist pattern 6 is etched by several tens of nanometers in thickness by the RIE method using sulfur hexafluoride (SF6 ) as an etching gas. When the plasma treatment is performed, a slope part 6a in the lower section of the resist pattern is removed and the pattern 6 is formed on a vertical sidewall. In the plasma treatment, the etching is performed by adjusting the flow rate of the SF6 gas to 40 sccm, pressure of the gas to 20 Pa, and RF power to 100W. The etching rates of the resist and GaAs under the above- mentioned etching condition becomes 550 /min and 30 /min, respectively. The hemming bottom 6a of the pattern 6 is removed by performing the plasma treatment for about one minute under the above-mentioned condition. Therefore, the etching can be performed without deteriorating the etching rate and nor roughening the surface at the time of etching a GaAs layer in the succeeding process, because the resist pattern can be shaped without oxidizing the surface of the GaAs layer.