Complexing Agents (CAs) for Semiconductor Cleaning Chemistries: Characterization of CA Lifetimes by UV/VIS-Spectroscopy

摘要

Single chemistry cleaning may serve as a potential substitute for the conventionally used RCA cleaning sequence to meet progressively stringent requirements during semiconductor fabrication. The current study involves stability determination of aromatic complexing agents (CAs) such as catechol, Shqsa and pyridinone-type compounds employed in 1/4/20 APM and related cleaning mixtures (like 1.65/1/5 NC and TPM) at 35°C and 50°C. The CA concentration was monitored as a function of UV absorption after periodic sampling from corresponding solutions. CA degradation was assumed to follow a linear or an exponential decay representing rate equation laws of zeroth and first or pseudo-first order, respectively, and the lifetimes of the CAs (t_(1/2)) deduced accordingly. Compound 'X' was the most stable of all CAs under investigation. All others were less stable by a factor of 3 - 5. The stability of CAs may be discriminated according to their radical scavenging capability and where applicable the oxidation potentials of their tautomers.