Comment stsetch SNF 2010-08-27 09:19:41: Test wafer results

I etched a bulk-Si test wafer for 120 min using the DEEP recipe and Al holder.
SPR220 thickness (avg. of 5 points):
Start: 69879 A
End: 55869 A
Etch rate: 117 A/min
Within expected range.
Backside Helium (sccm?):
Start: 1.62
End: 1.52
Etch step:
SF6: 129.2 sccm
Pressure: 32 mT
Dep step:
C4F8: 84.5 sccm
Pressure: 19 mT
Si trench depths:
Right: 249.8 um
Middle: 235.5 um
Left: 230.2 um
Locations on wafer when facing tool. Uniformity is poor. Trench profiles are W shaped (faster etching at the sidewalls). Minimum trench width is 150 um. SEMs available if needed.
Reflected power was always 0-1 W, except when switching where it jumped to as high as 180 W for a couple seconds.
Mary, Nancy or Elmer will take my time slot today (10a-2p) to continue assessing tool performance.