Abstract
This paper aims to investigate the residual film thickness of negative photoresist with varied exposure dose after developmemt, namely, the contrast curve, affected by the photoinitiators. Three kinds of photoinitiators (Irgacure 369, Irgacure 907, and Irgacure OXE-02) were used as studied materials, blending with carboxylated cresol acrylic resin and trimethylolpropane triacrylate in co-solvent of propyleneglycol monomethyl ether acetate and cyclohexanone. As shown in the results, the photoinitiator grouped with oxime ester, such as Irgacure OXE-02, can be used to increase the contrast of negative-work photo-resist in the photolithography, and reduce the exposure dose needed for cross-linking reaction due to the more free radicals produced by the photoinitiator with a wider spectral absorption range. This suggests that the contrast curve method may be employed to optimize and integrate the photosensitive polymer in the photolithography process.
