Process Hierarchy

If you are interested in this process, either by itself or as part of a longer processing sequence, please send us email at engineering@mems-exchange.org or call us at (703) 262-5368
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  Silicon dioxide plasma etch (anisotropic, MOS clean)
Process characteristics:
Depth
Depth of material removed by etch process
Depth*
Depth of material removed by etch process, must be 0.01 .. 1 µm
0.01 .. 1 µm
Ambient
Ambient to which substrate is exposed during processing
 trifluoromethane, carbon tetrafluoride, helium, oxygen, argon, nitrogen
Aspect ratio 10
Batch size 4
Etch rate 0.3 µm/min
Material silicon dioxide
Min feature size 1 µm
Pressure
Pressure of process chamber during processing
 250 mTorr
Selectivity
Primary material removal rate divided by removal rates of secondary materials (i.e., factors by which primary material is removed faster than secondary materials)
 photoresist (category): 7.5, silicon dioxide: 1, silicon: 7.5
Sides processed either
Temperature 65 °C
Wafer size
Wafer size
Equipment Applied Materials Precision 5000 (chamber B)
Equipment characteristics:
Wafer holder
Device that holds the wafers during processing.
 mechanical clamp
Wafer materials
List of wafer materials this tool can accept (not list of all materials, just the wafer itself).
 silicon, quartz (single crystal), silicon on insulator, silicon germanium
Wafer thickness
List or range of wafer thicknesses the tool can accept
 350 .. 600 µm
Comments:
  • This is an MOS clean machine.
  • Resist must be baked at 110 degC at least 24 hrs before etching.
  • No resist allowed on backside of wafers.
  • Resists thicker that 1.6 um will burn. Users should consider an alternate masking material.
  • Quartz wafers must have non-transparent material on backside.
  • The outer 5 mm of the edge of the wafers must be free of resist to avoid wafers sticking the the chuck clamp.
  • Endpoint detection available, assuming etch stop material is silicon