Method for deep silicon etching using gas pulsing

摘要

Techniques disclosed herein include methods for etching deep silicon features using a continuous gas pulsing process that etches high aspect ratio features having a relatively smooth profile. Such methods provide an etch rate faster than time-multiplexed etch-deposition processes. Techniques include using a continuous process that comprises a cyclic gas-pulsing process of alternating chemistries. One process gas mixture includes a halogen-containing silicon gas and oxygen that creates an oxide layer. A second process gas mixture includes a halogen-containing gas and a fluorocarbon gas that etches oxide and silicon.

主权项

1. A method for etching deep silicon features on a substrate, comprising:
disposing a substrate on a substrate holder in a plasma processing system, the substrate having a patterned mask layer defining openings that expose a silicon surface; flowing a first process gas mixture into the plasma processing system, the first process gas mixture comprising silicon, oxygen, and at least one halogen; flowing a second process gas mixture into the plasma processing system, the second process gas mixture comprising a halogen-containing gas and a fluorocarbon gas; forming plasma from the first process gas mixture and the second process gas mixture such that the silicon surface, through the patterned mask layer, is exposed to the plasma; forming an oxide layer on sidewalls and bottom surfaces of one or more silicon features within the substrate using products from the first gas mixture and the plasma; and etching the one or more silicon features within the substrate using products from the second process gas mixture and the plasma.