Forming a bottle-like deep channel in a substrate comprises etching to form an upper region of the channel in the substrate using a plasma gas, etching to form a bottle-like base region of the channel and vertically etching

摘要

Process for forming a bottle-like deep channel in a substrate comprises etching to form an upper region of the channel in the substrate using a plasma gas consisting of NF3, HBr and He-O2 at a predetermined pressure; etching to form a bottle-like base region of the channel by raising the HBr flow, raising the NF3 flow and adjusting the through-flow ratio of HBr to He-O2 to above 4; and vertically etching the substrate so that the bottle-like profile of the channel is maintained by raising the predetermined HBr flow and reducing the predetermined pressure. Preferred Features: The predetermined pressure is 80-110 Torr. The through-flow ratio of HBr, NF3 and He-O2 in the first step is 87: 13: 35, in the second step is 200: 20: 20 and in the third step is 150: 13: 20.