RESIST ASHING AT ROOM-TEMPERATURE USING SURFACE-WAVE-PRODUCED PLASMAS

Resist ashing characteristics at room temperature with O2/CF4 plasma in the surface-wave-plasma (SWP) asher are reported. The characteristics of ashing nonpatterned resists and resists on Al alloy were observed. A high ashing rate of 2-mu-m/min was compatible with a high selectivity of 500 to SiO2 when the CF4 concentration was 6%. In ashing of a resist on Al alloy etched with Cl2/BCl3, a notch under the Al alloy and the resist-residue did not exist. In ashing of a resist on Al alloy etched with Cl2/SiCl4, the resist-residue remained. The residue was composed of C, Si, and Al at least. The residue was removed by a wet cleaning. As a result, the ashing process using an SWP asher has no significant problem and the SWP asher performs very well.