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TMAH is used in two main areas of semiconductor processing. In higher concentrations (25%) it is used as a crystallographic etch of silicon – similar to KOH etching. In lower concentrations (2.4%), it is used as a positive photoresist developer.

(warning) Higher All concentrations of TMAH solutions pose a severe toxic threat.

  • TMAH acts to interfere with the nervous system, often shutting down breathing.
  • There is no antidote at this time.
    • Death has occurred shortly (30 min) after exposure to quantities of
    higher concentration
    • 25% TMAH solutions (
    greater than
    • as little as 7% body surface area exposed).
    • Death occurred with 12% BSA of 8.75% TMAH
    • So far, there have been no reported deaths due to exposure of developer strengths (one case had the patient on a respirator in intensive care - 28% BSA of 2.38% TMAH).
  • The key to TMAH poisoning appears to be strength of solutions and area exposed. Time to decontamination does not appear to be important – absorption through skin may be very rapid.
  • Symptoms of TMAH poisoning
    • Muscle weakness
    • Salivation
    • 2nd or 3rd degree burns
    • Irregular breathing and heartbeat
    • Progressing to coma, shock and in most high concentration cases – death.