Photoresist Characterization and Wet Strip after Low-k Dry Etch

摘要

In new semiconductor technology generations, with BEOL feature sizes shrinking to 65 nm andbelow, the amount of damage induced by plasma etch and ash processes to porous low-k materials isbecoming an issue [1]. The k-value degradation from densification and chemical modification of thelow-k is generally unacceptable, while the removal of the damaged layer may affect criticaldimension (CD) control too severely to be taken into account in the design. Consequently, all-wetprocesses are gaining renewed interest for the removal of post-etch photoresist (PR). However,specifications on material loss and k-value integrity considerably reduce the operating space for apurely wet-chemical clean.