TMAH and its Alternatives: Where Do We Go From Here?
Kevin McLaughlin; Hidde van Assendelft; Jerry Windisch
(SACHEM Inc., Austin, TX)
The semiconductor industry has a long history of using high-pH chemicals directly and in formulations for lithography, etching, cleaning, polishing, and stripping applications. As performance and purity requirements increased in early fabrication processes, tetramethylammonium hydroxide (TMAH) quickly supplanted metal-containing hydroxides and has long reigned as the strong base of choice in fab operations. However, concerns over the toxicity of TMAH combined with reports of serious incidents involving TMAH exposure have greatly increased scrutiny of this material by both the semiconductor industry and regulatory entities. This has created a strong and growing interest in identifying and incorporating alternatives to TMAH in semiconductor processing. As a leader in quaternary chemistry, SACHEM has long championed TMAH safety and has developed a portfolio of alternative products for use in semiconductor applications. In this presentation, we will review these alternatives, their performance characteristics, and provide an overview of safe handling practices for these types of chemicals. In addition, we will discuss technology available for the recovery and reuse of quaternary compounds such as TMAH and its alternatives.