Poly-Si etching using electron cyclotron resonance microwave plasma sources with multipole confinement
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- SEMATECH, Austin, TX (United States); Advanced Micro Devices, Austin, TX (United States)
In this study, mirror field and single coil 2.45 GHz electron cyclotron resonance microwave plasma sources were coupled to a multipole, multicusp plasma confinement system and used to produce chlorine plasmas for poly-Si etching. Scanning Langmuir probes were used to study the effect of process parameters on plasma potentials, plasma density, plasma density uniformity, and electron temperature, while poly-Si etching experiments on 150 mm diam wafers were used to relate process parameters and Langmuir probe results to etch rate, SiO2 selectivity, photoresist selectivity, and etch uniformity. Radio-frequency substrate bias at 13.56 MHz was used for ion energy control, and the addition of a third coil below the substrate plane was found useful for fine-tuning the radial plasma uniformity. Undoped poly-Si etch rates ≳3000 Å/min, Si/SiO2 etch selectivities ≳25 and 150 mm diam etch uniformities <2% at 1 σ were obtained, but not simultaneously. Tradeoffs in choosing operating conditions for optimum poly-Si etch performance will be discussed.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10110758
- Report Number(s):
- CONF-911132--11; ON: DE92005114
- Journal Information:
- Journal of Vacuum Science and Technology A, Journal Name: Journal of Vacuum Science and Technology A Journal Issue: 4 Vol. 10; ISSN 0734-2101
- Publisher:
- American Vacuum Society / AIP
- Country of Publication:
- United States
- Language:
- English
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