Weak-polar solvents like PGMEA (Propylene Glycol Monomethyl Ether Acetate) or CHN (Cyclohexanone) are used to dissolve hydrophobic photo-resist polymers, which are challenging for traditional cleaning methods such as distillation, ion-exchange resins service or water-washing processes. This paper investigated two novel surface modifications to see their effectiveness at metal removal and to understand the mechanism. The experiments yielded effective purification methods for metal reduction, focusing on solvent polarities based on HSP (Hansen Solubility Parameters), and developing optimal purification strategies.
Recently nylon filters have been widely implemented in photolithography processes to improve the
yields because many IC and photoresist manufacturers have empirical evidence indicating that the
nylon membrane can adsorb impurities. However, the mechanism by which the nylon membrane
reduces defects is unclear. It is useful to study different defect-causing mechanisms by focusing on the
particular components of photoresists. In this paper various adsorption tests were performed utilizing
surface modification and different photoresist components to measure the effect of nylon membranes
on resist properties, including surface tension, PAG (photoacid generator) concentration and quencher
concentration. Ultimately, the study hopes to determine the most effective way to increase yields by
focusing on how to best implement a nylon filtration strategy.