Relationship between deprotection and film thickness loss during plasma etching of positive tone chemically amplified resists

A study of the relationship between deprotection and film thickness loss during plasma etching of positive tone chemically amplified (CA) resists was performed. The degree of cleavage occurring under plasma etching conditions was greatly affected by the activation energy of the deprotection reaction. The extent of deprotection was directly influenced by the nature or acidity of the plasma chemistry. Acid plasma induced deprotection and exposure of photoacid generators (PAG) within the etch chambers were two mechanisms during the deprotection. Etch rate in all cases were considered linear and the deprotection-related film thickness loss was insignificant.