Specific Process Knowledge/Etch/Etching of Silicon: Difference between revisions

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*[[/Si etch using RIE1 or RIE2|Dry etch using RIE1 or RIE2]]
*[[/Si etch using RIE1 or RIE2|Dry etch using RIE1 or RIE2]]
*[[/Si etch using ASE|ASE (Advanced Silicon Etch)]]
*[[/Si etch using ASE|ASE (Advanced Silicon Etch)]]
*[[Etch/DRIE-Pegasus|DRIE-Pegasus (Silicon Etch)]]
*[[Specific Process Knowledge/Etch/DRIE-Pegasus|DRIE-Pegasus (Silicon Etch)]]


==Comparison of KOH etch, wet PolySilicon etch, RIE etch and ASE etch for etching of Silicon==
==Comparison of KOH etch, wet PolySilicon etch, RIE etch and ASE etch for etching of Silicon==

Revision as of 08:20, 11 May 2011

Etch of silicon can be done by either wet etch or dry etch. The standard setups for this here at DANCHIP are:

Wet etches:

Dry etches:

Comparison of KOH etch, wet PolySilicon etch, RIE etch and ASE etch for etching of Silicon

KOH PolySilicon etch RIE ASE
General description
  • Anisotropic etch in the (100)-plan
  • High selectivity to the other plans
  • Isotropic etch in Silicon and Polysilicon
  • Can etch isotropic and anisotropic depending on the process parameters
  • Anisotropic etch: vertical sidewalls independent on the crystal plans
  • As RIE but better for high aspect ratio etching and deep etches (higher etch rate)
  • Good selectivity to photoresist
Possible masking materials
  • Silicon Nitride
  • Silicon Oxide
  • Photoresist
  • Photoresist
  • E-beam resist
  • Silicon Oxide
  • Silicon Nitride
  • Aluminium
  • Chromium (ONLY RIE2!)
  • Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)
  • Photoresist
  • Silicon Oxide
  • Silicon Nitride
  • Aluminium
Etch rate
  • Si(100) @80oC: 1.29+0.05 µm/min
  • Si(100) @70oC: ~0.7 µm/min
  • Si(100) @60oC: ~0.4 µm/min
  • ~100-200 nm/min, highly dependent on doping level
  • <40nm/min to >600nm/min depending on recipe parameters and mask design
  • <130nm/min to >5.6 µm/min depending on recipe, mask design and aspect ratio.
Size of substrate
  • 4" in our standard bath
  • 4", 2" in "Fumehood KOH"
  • 4" in our standard bath
  • 4" (or smaller with carrier)
  • 6" (when it is set up for 6") and 4" (or smaller if you have a carrier)
Batch size
  • 25 wafers at a time
  • 1-5 wafers in "Fumehood KOH"
  • 25 wafers at a time
  • One wafer at a time
  • One wafer at a time
Allowed materials
  • Silicon
  • Silicon Oxide
  • Silicon Nitride
  • Silicon Oxynitride
  • Other materials (only in "Fumehood KOH")
  • Silicon
  • Silicon Oxide
  • Silicon Nitride
  • Silicon Oxynitride
  • Photoresist
  • Silicon
  • Silicon Oxide
  • Silicon Nitride
  • Silicon Oxynitride
  • Photoresist
  • E-beam resist
  • Aluminium
  • Chromium (ONLY RIE2!)
  • Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)
  • Silicon
  • Silicon Oxide
  • Silicon Nitride
  • Silicon Oxynitride
  • Photoresist
  • E-beam resist
  • Aluminium