Physical and lithographic properties of structurally diverse acetal-derivatized hydroxy styrene polymers are reported. The dissolution and thermal properties of the acetalblocked polymers vary with the size of the pendent acetal moiety. The lithographic performance of the resists containing "bulky" acetal-derivatized polymers was found to be superior to those containing non-bulky acetal functionalized polymers. In the cases where the acidolysis products of the bulky acetal-based polymers are non-volatile alcohols, the post-exposure volatilization, film shrinkage and plasma etch resistance were found to be significantly improved. Bulky acetal-derivatized polymers also show excellent thermal and shelf life stability.

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ABSTRACT:Direct polycondensation reactions of various nylon salts prepared from diamines and dicarboxylic acids were carried out under mild conditions with triphenylphosphine and halides. Reaction conditions including the monomer concentration, amount of reagents, kind of halides, solvents and organophosphorus compounds, and temperature were investigated. A combination of triphenylphosphine and tetrabromomethane was found to be satisfactory for the aliphatic polyamide synthesis. Nylon 6, 10 having the highest molecular weight was obtained with the molar ratio of triphenylphosphineltetrabromomethanelcarboxyl groups of the monomer= 1.511.511.0 in pyridine at 40°C.KEY WORDSPolycondensation reaction is usually carried out at elevated temperatures above the melting points of the resulting polymers in order to eliminate volatile products so as to shift the equilibrium towards the polymer formation. Several methods have been developed for the synthesis of polyamides under mild conditions1 even at room temperature, where the polycondensation reaction was promoted using active monomers such as dicarboxylic acid chlorides or active diesters.Phosphorylation reaction has been applied1-5 for the polyamide synthesis from diamines and dicarboxylic acids, so that the polycondensation reaction takes place under mild conditions. Although the yield of polyamide was almost quantitative, the solution viscosity of the product did not exceed 0.4. The difficulty of synthesizing aliphatic polyamides under mild conditions may be ascribed to the high basicity of aliphatic diamines which presumably causes significant side reactions such as the formation of P-N linkages and the less solubility in solvents.Recently, an aromatic polyamide of a high molecular weight could be obtained in quantitative yield under mild conditions 5 with triphenylphosphine and hexachloroethane in pyridine. 6 This paper deals with the synthesis of high molecular weight aliphatic polyamides from nylon salts, which are prepared from diamines and dicarboxylic acids, by the direct polycondensation with the combination of triphenylphosphine and a halide.

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