Photoresist Reactive Ion Etching at Reduced Etch Rate
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
A cathode material for dry etching a trilayer structure is proposed, by means of which an an etch rate ratio of photoresist/SiNO or Si3N4 layer of < 1 is obtained. The figure shows a mask for a trilayer process. The mask is positioned on a wafer and was produced from a thick photoresist layer, an SiNO or an Si3N4 layer and a thin photoresist layer as the top layer. A high resolution necessitates a low etch rate for the photoresist mask, so that at a given resist thickness, deep structures can be etched into the underlying material. Normally, however, the etch rate of a photoresist, such as AZ 1350 (Shipley Company), is about 30% higher than that of an SiNO or an Si3N4 layer. There is no known etch gas, by means of which an etch rate ratio of resist/SiNO or Si3N4 layer of < 1 could be obtained.