Abstract
Cresol formaldehyde novolac resins (Cre/Form) having hard properties cannot be applied minutely the positivetype photoresist material onto dry films. Therefore, a new development was needed, so we carried out the synthesis and application of cresol novolac resins having flexibility. The polycondensation reactions of cresols with succinaldehyde, glutaraldehyde, and adipaldehyde were carried to obtain cresol novolac resins. The obtained resins having both dissolving rate for alkaline aq. solution below 1000Å/sec and Mw over 3000 were chosen for the test. The 5 μm thick cast films of the obtained resin were applied onto polyimide films in order to evaluate the flexibility properties of the obtained resins by observation of their bent parts. Though the Cre/Form resin of the bent part was scattered, the obtained resins just cracked. The flexibility of the obtained resin was also confirmed from the results of the dynamic storage modulus measurement, too. The lithography performance of the obtained resin coated 1.5 μm in thickness onto the silicon wafer was examined. The residual membrane thickness was high (90%) and the resolution of the resist was up to 2.5 μm.
