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Wet etchants for silicon and silicon compounds
written 8.1 years ago by gravatar for hetalgosavi hetalgosavi • 1.6k modified 8.1 years ago by gravatar for juilee juilee • 100

Mumbai University > Electronics Engineering > Sem 8 > MEMS Technology

Marks: 3M
mems technology
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written 8.1 years ago by gravatar for hetalgosavi hetalgosavi • 1.6k
  • HNA for isotropic etching at room temperature.
  • Alkaline chemicals with ph> 12 for anisotropic etching.

  • Popular anisotropic etchants are:

    KOH (potassium hydroxide)

    EDP (Ethylene-diamine and pyrocatecol)

    TMAH (Tetramethy ammonium hydroxide)

    Hydrazine

  • Most etchants are used with 1 : 1 by weight mixture with water.
  • Typical etching rates are:
Materials Etchants Etch Rates
Silicon in<100>
Silicon in <100>		 KOH
EDP		 0.25 – 1.4 µm/min
0.75 µm/min
Silicon dioxide
Silicon dioxide		 KOH
EDP		 40 -80 nm / hr
12 nm/hr
Silicon nitride
Silicon nitride		 KOH
EDP		 5 nm/hr
6 nm/hr
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