Suppression of ArF Photoresist Deformation in Inductively Coupled Plasma (ICP)

초록

The ArF photoresist, which can be exposed at 193 nm wavelengths, has been applied in semiconductor manufacturing for a 0.1? feature size and beyond. Recently reported results show that ArF photoresist is much weaker and thinner than KrF (248 nm) photoresist. It will be a challenge in plasma etch process to maintain the integrity of ArF photoresist, leading to be free of resist deformation during critical etch process such as Si3N4 hardmask opening. In this paper, plasma etch resistance and morphological changes of ArF photoresist in various plasma etching environments was checked. To determine the main etch parameter causing deformation of ArF photoresist, etching parameters in Inductively Coupled Plasma (ICP) source was varied and compared the results. We present alternative etch techniques consists of a triple sequence of protective layer coating, polymer/ photoresist trimming and final etch step. The effect of fluorocarbon layer formation on selectivity and etch profile will be discussed.