PURPOSE: To enable patterning precision to be improved easily and safely, by performing reactive ion etching, in which freon-group gas is used, to develop a lower-layer resist.
CONSTITUTION: A pattern 22 having a step by difference is formed on a wafer substrate 21, and the pattern 22 is coated with a polymethacrylate methyl (PMMA) resist 23 serving as lower-layer resist. Then, UV posi resist is applied as an upper-layer resist. Thereafter, a mask 25 is used to perform exposure developing. Then, with the developed upper-layer resist pattern 24a serving as mask, general overall exposure is performed by distant ultraviolet rays (DUV). Thereafter, developing of the lower-layer resist 23 is performed by using RIE technology as it is called. For example, 60 sccm of C2F6+CHF3 in a ratio of 80:20 is introduced, pressure is regulated to 80 pa, a high frequency wave of 13.56 MHz is impressed on electrodes, and besides temperature at a wafer-mounted side of the parallel plate electrodes is made a little higher than that at the other side. Hence, dry developing of the PMMA resist 23 is performed.
OTSUKA HIROSHI
MATSUI TAKAYUKI
ITO YOSHIO
