Specific Process Knowledge/Etch/Etching of Silicon Oxide/SiO2 etch using Plasma Asher
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SiO2 can be etched in the Plasma Asher using CF4
Test work done January 2014 by Lis Nielsen and Berit Herstrøm @Danchip
SiO2 can be etched in the Plasma Asher using CF4. This gives an isotropic etch. In test2 the SiO2 layer has been etched through and there is a small over etch in the Silicon substrate. The masking material is 100nm Al. Etch rate and uniformity measurements have been done on wafers with no mask.
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Plasma Asher parameter settings and results for the tests | ||||||
Test1 | Test2 | |||||
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O2 flow | 0 sccm | 0 sccm | ||||
N2 flow | 0 sccm | 0 sccm | ||||
CF4 flow | 200 sccm | 200 sccm | ||||
Power | 1000 W | 1000 W | ||||
Process Time | 10 min | 50 min | ||||
Average Etch rate on wafer (5 points measured) | 22.6 nm/min | 31.8 nm/min | ||||
Non-uniformity over the wafer (5 points measured) | ±10.8 % | ±11.0 % | ||||
Non-uniformity plot | ||||||