| Popis: |
Photomask resist strip processes have traditionally used the sulfuric-peroxide-mix, known as SPM, or Piranha. This paper details a recent investigation into the utilization of solvent-based resist strip solutions applied to photomask resist stripping. Studies of two commercially available solvents are documented in this report: one formulated for positive resist stripping [Chem A, which contains a primary amine, glycol and is semi-aqueous], and another rated for 'hard-to-remove' positive resist stripping [Chem B, which contains glycol ethers, organic cyclics -- all proprietary]. Resist types, such as IP3600, and most Chemically Amplified Resists (CAR) will strip easily with any of the chemicals mentioned, however, other adverse effects may deter one from using them. The screening process employed in this study monitors effects of processing on EAPSM phase and transmission, AR layer reflectivity changes and surface ionic analytical comparisons. Chem A and B will show similarly low phase and transmission shifts at higher temperature and longer process times, while reflectivity data shows lower level changes associated with the use of Chem A (favorable). As for surface ionic contamination: on F and Cl contaminated surfaces, Chem A shows favorable results. Overall Chem A seems to be the appropriate choice for more thorough investigation in a production mask-making environment. |
