Reactor characterization for a process to etch Si(3)N(4) formed on thin SiO(2)

• Published in: IEEE transactions on semiconductor manufacturing 1993-08, Vol.6 (3), p.290-292
• Main Authors: Riley, P E, Defonseka, B N, Sum, J C, Figueredo, D
• Format: Article
• Language: English
• ISSN: 0894-6507
• DOI: 10.1109/66.238183

A plasma etching process for patterning LPCVD (low-pressure chemical vapor deposition) Si(3)N(4) which has been formed on thin thermally grown SiO(2) has been developed and characterized with an Applied Materials 8110 batch system using 100-mm-diameter silicon wafers. To fulfill the primary process objectives of minimal critical dimension (CD) loss (~0.08 mum), vertical profiles after etch, retention of some of the underlying thermal SiO(2), and batch etch uniformity, the reactor has been characterized by evaluating the effects of variation of reactor pressure (15 to 65 mTorr), O(2) concentration by flow rate (30 to 70%) of an O(2)/CHF(2) mixture, and DC bias voltage (-200 to -550 V). Analysis of the resulting etch rate, etch uniformity, dimensional, and profile data suggests that satisfactory processing may be achieved at low reactor pressure (~25 mTorr), 50-60% O(2) by flow rate in O(2)/CHF(3), and low DC bias (-200 to -250 V)