Relationship between Dissolution Inhibitors and Dissolution Rate of Resist in Chemically Amplified Three-Component Positive Resist

For chemically amplified electron beam (EB) resist composed of partially tert-butoxycarbonyl (tBOC) protected poly(p- vinylphenol) (PVP), a dissolution inhibitor, and an acid generator, the effect of the dissolution inhibitors on the dissolution characteristics of resist are investigated. As dissolution inhibitors, hydroquinone protected by a tert-butoxycarbonyl group (B-HQ) and isophthalic acid protected by a tert-butyl group (B-IP) are used. Dissolution inhibitors (B-HQ and B-IP) become dissolution promoters (HQ and IP) after exposure. The dissolution rate of the resist consisting of B-IP was faster than that of B-HQ in the exposed area. pKa of IP is smaller than that of HQ, and the acidity of IP is higher than that of HQ. Therefore IP enhances the solubility of the matrix resin in the alkaline developer. A 0.14 µ m line and space pattern is fabricated at 17.5 µ C/cm2 using 50 keV EB in the resist consisting of B-IP.