Monitoring Tetramethylammonium Hydroxide (TMAH) in Developer

For the production of semiconductors it is of the utmost importance to use chemicals with an extremely high purity. The presence of impurities (even in very small proportions) can have large effects on the electrical properties of the material. The same counts for the concentrations of the chemicals used during the production process. Tetramethylammonium hydroxide (TMAH, N(CH₃)₄OH) is an alkaline ingredient in photoresist developer, kept at a concentration between 2.38–2.62% in many applications and is highly effective in stripping off the acidic photoresist as it becomes soluble in the developer. This application note demonstrates how a process analyzer configured for titration performs the accurate analysis of tetramethylammonium hydroxide (TMAH) using a combined pH electrode