Novolacs With Alternating P-Cresol & Polyhydroxyphenyl Monomer Units: Developer Cationic Effects And Thermal Properties

Novolacs which alternate p-cresol monomer units with polyhydroxyphenyl monomer units have been synthesized by acid catalyzed condensation of 2,6-bis(hydroxymethyl)-p-cresol with polyhydroxybenzenes such as resorcinol or 4-chlororesorcinol. These novolacs are highly alkaline soluble and exhibit improved glass transition temperatures relative to conventional novolacs. Unexpected developer cation effects have been observed on the dissolution times of some of these novolacs. The effect of molecular weight on these effects will be discussed for one system. The dissolution discrimination and inhibition of a 4- chlororesorcinol containing novolac was examined relative to a standard m-,p-cresol novolac and polyvinyl phenol. Images produced from a resist using a p-cresol/ 4-chlororesorcinol novolac showed no significant image degradation at 200 degrees C.