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.
What is TMAH etching?
KOH and TMAH are anisotropic silicon etches, used to make V-grooves, membranes, and holes through wafers, as well as other devices. TMAH is a organic hydroxide and stands for Tetramethyl ammonium hydroxide. KOH for etching comes in bottles of 45% by weight concentration and TMAH comes as 25% by weight concentration.
What is the formula for tetramethylammonium hydroxide?
How should you dispose of tetramethylammonium hydroxide?
Discharge into the environment must be avoided. Soak up with inert absorbent material and dispose of as hazardous waste. Keep in suitable, closed containers for disposal.
Is ammonia a solution?
Ammonia has alkaline properties and is corrosive. Ammonia gas dissolves easily in water to form ammonium hydroxide, a caustic solution and weak base. Ammonia gas is easily compressed and forms a clear liquid under pressure. Ammonia is usually shipped as a compressed liquid in steel containers.
Does TMAH etch SiO2?
120: The concentration and temperature-dependent selectivity of the etching rate of (100) – Si and SiO2 in TMAH (left graph) and KOH (right graph). In TMAH, the etch rates of Si and SiO2 have their maximum at different TMAH concentra- tions, which is why their ratio shows a local minimum.
Is TMAH a strong base?
TMAH is a strong base; the 25% solution in water has a pH of greater than 13. The odor of TMAH has been described as a strong, ammonia-like smell.
What is tetramethylammonium hydroxide used for?
General Description and Uses 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.
Is Tmah toxic?
Highly toxic liquid. It is a very strong base with a pH >13. Concentrations between 10 and 25% TMAH will cause 2nd and 3rd degree burns if exposed to skin. Corrodes certain metals. Exposure may result in intense burning of the eyes, nose, throat, lungs and skin.
What is ammonia solution formula?
What are the effects of tetramethylammonium hydroxide ( TMAH )?
• One worker with 28% of body surface contaminated developed muscle weakness, salivation, dyspnea, hyperglycemia, and 1st and 2nd degree burns • Victim required medical intervention with endotracheal intubation and intensive care.
How many people have died from exposure to TMAH?
To better understand the toxicity following dermal exposure to TMAH, we analyzed all cases with TMAH exposure reported to the Taiwan Poison Control Center (PCC-Taiwan). Case reports: In total, there were 13 cases of such exposure, including three patients who died after being exposed to 25% TMAH.
What are the effects of TMAH on the body?
In addition to alkalinity-related chemical burn, dermal exposure to TMAH may also result in respiratory failure and/or sudden death. The latter toxic effect has been of great concern in Taiwan after the occurrence of three fatalities in recent years.
How is TMAH used in the electronics industry?
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. These solutions are assigned the CAS# 75-59-2.