Felfe & Lynch
High contrast low metal ion positive photoresist developing method using aqueous base solutions with surfactants
A novel low metal ion developer composition used in a two step process which provided high contrast images and long developer bath life is provided. The process gives high contrast images. The substrate coated with positive photoresist is exposed then immersed in a "predip" bath, rinsed, and then, immersed in the developer bath, rinsed and dried. This process provided high contrast which does not decrease over the life of the developer system. The system consists of (1) a predip solution containing aqueous non-metal ion organic base and a cationic surfactant adjusted to a concentration that does not give development, and (2) a developer solution containing an aqueous solution of an non-metal ion organic base and a fluorochemical surfactant adjusted to a concentration that provides development. The high contrast is achieved by the cationic surfactant coating the resist and inhibiting the attack on the unexposed resist by the developer while permitting the developer to dissolve away the exposed resist.
Petrarch Systems, Inc.
G
G03F
inventional
James M. Andrew J.
Lewis Blakeney