The Third Fishenden Memorial Lecture: The Photo-Resist Story—From NiéPce to the Modern Polymer Chemist

At present with International Publishing Corporation Ltd, Paper read to the Society on 3 December 1963.

Abstract

The photo-resist was first used to provide eorly photographs, then became restricted to photomechanical applications, but recently has found widespread industrial uses. The first system was that of Niepce employing bitumen, but the dichromate methods soon took over. The practical drawbacks of the dichromate system urged more searching for improved methods employing new colloid binders and alternative light-sensitive agents, as well as two-layer systems. Diazo compounds have been shown to photo-crosslink in a similar manner to dichromate and the advent of diazo-resin condensates was important. Needs for a hydrophobic resist system caused much study of methods of sensitizing partially crosslin ed resins in solvent based systems. Poor stability of the systems prevailed, but a break-through occurred with polymers having inherent light sensitivity. The polyvinyl cinnamate system is outstandingly successful and other methods in which hydrophobic resins are sensitized with azides are also of interest. Photo-polymerization of monomer systems has been widely explored and certain processes have been developed. Reversed or direct positive systems are of interest and have received attention including several diazo methods. The ideal resist still remains to be found and the widening applications call for a variety of requirements in the product.

Notes

At present with International Publishing Corporation Ltd, Paper read to the Society on 3 December 1963.