Novel non-chemically amplified resist utilizing interaction between hexafluoroisopropylalcohol-containing styrene and photochemical acid generator

It is very important in the design of positive-type resists to consider the dissolution inhibition effect to form high-resolution patterns. Previously, the phenomenon of the inhibition of hexafluoroisopropylalcohol-containing polystyrene's dissolution into alkaline developers by sulfonium salt photochemical acid generator (PAG) was studied. In the present study, patterning was conducted to examine whether the above platform can be applied to positive-type resists. As a result, the platform was found to be useful for the formation of resist patterns and be a novel non-chemically amplified resist. On the other hand, a decrease in sensitivity was observed with an increase in the amount of PAG to enhance the dissolution inhibition effect, and an increase in the amounts of residues derived from decomposition products of PAG occurred by making the resist films thinner to improve the sensitivity. It was suggested that enhancement of the interaction and light transmittance by changing polymer compositions and structures of PAG and improvement of miscibility of PAG with alkaline developers might be effective. This resist system is expected to be one of the platforms as a solution when resist materials with nearly critical dimensions for which chemically amplified type cannot be applied are required in the future.