ABSTRACT
Photostimulated charge separation and its migration along the chain are key processes in polymer photo-conductor. Although extensive studies have been so far carried out to reveal the processes, no one has succeeded directly in measuring the primary processes. H. Miyasaka, T. Moriyama et al. detected the processes by combining the picosecond transient absorption spectra and transient dichroism. Photo-lithography research is currently aiming at development of a new type of photoresist polymer systems which have sensitivity in the deep-UV region and reactive ion etching durability. The sensitivity at shorter wavelengths is indispensable to achieve high lithographic resolution applicable to 256 Mbit or 1 Gbit DRAM. Photochromic reactions, in general, have no reaction threshold, and the memory is destroyed during multiple readout operations. Useful photochromic compounds must have non-destructive readout ability. Polymers having extended p-conjugation in the main chain exhibit a third order non-linear property.
