Synthesis of Novolak P-Cresol-Formaldehyde Resins for Deep UV Lithography
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
A series of cresol-formaldehyde novolak resins have been synthesized a evaluated with respect to their utility as matrix resins for deep ultraviolet (UV) resist formulations. One of the isomeric cresols, the p-isomer, provides a resin which has far greater optical transmission at 254 nm than the commercial cresylic acid novolaks used to formulate the classical photoresists. For the same molecular weight, the p-isomer also shows much lower solubility rate than the meta, ortho and the commercially available UV resin. This property has potential for high resolution resist material, when properly formulated with a photoactive compound.