Tetramethylammonium Hydroxide 25% (TMAH)

Tetramethylammonium Hydroxide 25% (TMAH) (CAS 75-59-2, molecular formula C4H13NO) is a process chemical for electronics and metal finishing, where trace metal content and particle contamination matter as much as headline assay. China Chemicals supplies it at 25% w/w in pack sizes from 1 L through to 200 L Drum, so laboratory trial quantities and full production volumes can be sourced from the same specification.

It is also traded as TMAH, TMAOH, Tetramethylammonium Hydroxide Solution. Every consignment ships with a batch-specific Certificate of Analysis and the current Safety Data Sheet, and material is stored and picked under stock rotation so you receive product well inside its shelf life.

Typical applications

Photoresist developer in semiconductor lithography
Anisotropic silicon wafer etching
Metal-ion-free cleaning of display and wafer surfaces
Surfactant and phase transfer catalyst
pH adjustment where sodium and potassium must be excluded

Technical specification

Chemical name	Tetramethylammonium Hydroxide 25% (TMAH)
Synonyms	TMAH, TMAOH, Tetramethylammonium Hydroxide Solution
CAS number	75-59-2
Molecular formula	C4H13NO
Appearance	Clear colourless liquid
Assay	25.0% w/w ± 0.5
Sodium (Na)	50 ppb max
Potassium (K)	50 ppb max
Iron (Fe)	20 ppb max
Particle count >0.5 µm	50/mL max
Appearance	Clear, particle free

Values above are typical and are confirmed on the Certificate of Analysis issued against each batch. Tighter specifications can be quoted where a process requires them.

Packaging and supply

Available in 1 L, 5 L, 25 L, 200 L Drum. Bulk, road tanker and export drum quantities are quoted on request, including FOB and CIF terms for international shipment. Pricing shown is per pack in USD, exclusive of freight and any applicable duties.

Handling and safety

Transport classification: UN1835 · Corrosive / Acute toxin, Class 8. Store in the original closed container in a cool, well-ventilated area away from incompatible materials, and handle using appropriate personal protective equipment. Read the Safety Data Sheet in full before use — it is issued with every order and is available on request before purchase.

Supply to industry only. Products are sold for legitimate industrial, laboratory and manufacturing use. We may request end-use details and business registration before releasing an order.