Agrochemical Intermediates, Dyestuff Intermediates, Pharmaceutical Intermediates, Syntheses Material Intermediates
25% & 50%
Tetramethyl ammonium hydroxide
Tetramethylammonium hydroxide (TMAH or TMAOH) is a with the molecular formula (CH3)4NOH. It is used as an of . It is also used as a basic solvent in the of acidic in the process. Since it is a , it is highly effective in stripping photoresist. It is also used as a in the synthesis of , to prevent .
TMAH solution is a strong base. The tetramethylammonium ion can damage nerves and muscles, causing difficulties in breathing and possibly death in a short period of time after exposure by contact even with a small amount. It also smells like dead fish, if it is not pure, from impurity. TMAH has virtually no odor when pure.
 Wet anisotropic Etching
TMAH belongs to the family of quaternary ammonium hydroxide (QAH) solutions and is commonly used to . Typical etching temperatures are between 70°-90°C and typical concentrations are 5-25 wt% TMAH in water. (100) silicon etch rates generally increase with temperature and decrease with increasing TMAH concentration. Etched silicon (100) surface roughness decreases with increasing TMAH concentration, and smooth surfaces can be obtained with 20% TMAH solutions.
Common masking materials for long etches in TMAH include ( and thermal) and . Silicon nitride has a negligible etch rate in TMAH; the etch rate for silicon dioxide in TMAH varies with the quality of the film, but is generally on the order of 0.1 nm/minute.