Tetramethylammonium hydroxide (TMAH or TMAOH) is a quaternary ammonium salt with the molecular formula N(CH3)4+ OH−. It is commonly encountered as concentrated solutions in water or methanol. The solid and solutions are colorless, or yellowish if impure.
TMAH solution is widely used in the electronics industry as a developer or cleaner. TMAH is typically one of several ingredients in etching / stripping mixtures, although it may also be used as a pure chemical. It is often used in solution in water, and less frequently, in methanol.
Buffered Oxide Etch (BOE) or just hydrofluoric acid is used for etching silicon dioxide on silicon wafers. Buffered oxide etch is a mixture of hydrofluoric acid and ammonium fluoride. Ammonium fluoride containing etches give silicon surfaces with an atomically smoother surface than HF.
KOH and TMAH are anisotropic silicon etches, used to make V-grooves, membranes, and holes through wafers, as well as other devices. ... KOH is simply the hydroxide of potassium. TMAH is a organic hydroxide and stands for Tetramethyl ammonium hydroxide.
