Modification of Photoresist by UV for Post-Etch Wet Strip Applications
In Back-End-of-Line processing, the remaining photoresist layer after plasma etch is traditionally removed using a plasma process. Plasma process was reported to induce damage to porous dielectric [1-3]. To minimize damage to low-k material, wet alternative methods of removal of photoresist layer on porous low-k dielectrics are gaining a renewed interest . However, the presence of a “crust” generated by etch plasma at the photoresist surface makes it impossible to completely remove by a pure organic solvent. Indeed, the crust, most likely composed of crosslinked polymer, is not soluble in organic solvents . For this reason, a UV pre-treatment is investigated to break cross-links in the crust or to modify the crust to enhance removal efficiency with solvent stripping in more advanced generations.
Paul Mertens, Marc Meuris and Marc Heyns
Q. T. Le et al., "Modification of Photoresist by UV for Post-Etch Wet Strip Applications", Solid State Phenomena, Vols. 145-146, pp. 323-326, 2009