Reactor characterization for a process to etchSi3N4 formed on thin SiO2 |
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| Authors: | Riley P.E. Defonseka B.N. Sum J.C. Figueredo D. |
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| Affiliation: | Hewlett-Packard Co., Palo Alto, CA; |
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| Abstract: | A plasma etching process for patterning LPCVD (low-pressure chemical vapor deposition) Si3N4 which has been formed on thin thermally grown SiO2 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 μm), vertical profiles after etch, retention of some of the underlying thermal SiO2, and batch etch uniformity, the reactor has been characterized by evaluating the effects of variation of reactor pressure (15 to 65 mTorr), O2 concentration by flow rate (30 to 70%) of an O2/CHF2 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% O2 by flow rate in O2/CHF3, and low DC bias (-200 to -250 V) |
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