Specific Process Knowledge/Etch/DRIE-Pegasus/Pegasus-4/SiO2 Etch/Cr mask

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Unless otherwise stated, all content in this section was done by Berit Herstrøm, DTU Nanolab

Start parameters, variations noted in the gallery headline Recipe name: no 10 with lower platen power
Coil Power [W] 2500
Platen Power [W] 200
Platen temperature [oC] 20
H2 flow [sccm] 25.6
C4F8 flow [sccm] 25.6
He flow [sccm] 448.7
Pressure Fully open APC valve (8-9 mTorr)
Electromagnetic coils (EM) 'outer coil' / 'inner coil' '2 A' / '30 A' (PLEASE DO NOT RUN WITH THESE SETTINGS FOR MORE THAN 6 MIN)
  • 100 nm Cr mask etched in ICP metal with 500nm DUV neg resist (NUV 2300-0.5) and 65 nm barc.

Results

Temporary conclusions on how the process parameters affect the results in this study: What process parameters affect the results?
  • Going from full wafer to small piece on Si carrier:
    • Seemed to give more sidewall passivation
  • Platen power: lowering the platen power gives
    • more sidewall passivation
    • lower etch rate
    • Less trenching
  • Removing the H2 gave:
    • less sidewall passivation
  • Adding O2 gave:
    • less sidewall passivation
  • Process pressure/total gasflow rate
    • Reducing total gasflow rate which reduced the pressur inside the chamber gave:
      • less sidewall passivation
      • Reduced the CD (Critical Dimensions)
  • Coil power: Reducing coil power
    • less CD loss
    • more sidewall passivation
  • Increasing process time:
    • less sidewall passivation
    • more sidewall bow
    • CD loss due to larger mask faceting
  • Sidewall passivation
    • Sample size
    • Platen power
    • Coil power
    • H2 flow
    • O2 flow
    • Total gas flow rate/pressure