Photoresists have been widely used as patterning materials for electronic devices such as displays and semiconductors. Understanding pattern formation mechanisms is essential for the efficient development of resist materials. In particular, the dissolution mechanism of resist materials is an important process in pattern formation. In this study, the dissolution mechanisms of negative-type resists for display manufacture were investigated using a quartz crystal microbalance (QCM) method. The changes in frequency during development were measured for polymer and resist films. The observed major trend was as follows. The development type changed from an insoluble state to a peeling type and a dissolution type with Case II diffusion with an increase in the acid value of the polymers. The characteristics of the dissolution with Case II diffusion are the formation of a transient swelling layer (dissolution front) and steady-state front motion (linear weight loss). For the dissolution with Case II diffusion, the dissolution time and the original thickness of the transient swelling layer decreased with an increase in the acid value of the polymers.
Photoresists are an indispensable technology used for manufacturing electronic devices such as displays and semiconductors. In this study, we investigated the relationship between C=C double bond conversion and dissolution kinetics in cross-linking-type photoresists used for display manufacture using real-time Fourier transform infrared spectroscopy (FTIR) and quartz crystal microbalance (QCM) methods. To improve photoresist performance, it is important to understand the development mechanism of photoresists. Two kinds of polymers (a polymer with peeling-type dissolution and a polymer with a dissolution type with Case II diffusion) were used. 1,2-Octanedione-1-[4-(phenylthio)-2-(O-benzoyloxime)] and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide were used as photoinitiators. The dissolution was of the peeling type when the polymers were formulated as a typical cross-linking-type photoresist. With increasing conversion ratio of C=C double bonds, the rate of developer intake decreased and the impregnation threshold before the onset of peeling increased and then decreased. It was also found that the dissolution kinetics were affected by the radicals generated upon the decomposition of photoinitiators.
The absolute quantum efficiency of free radicals is one of the most important primary parameters in UV curing processes initiated by photoradical initiators. Herein, a novel experimental protocol has been developed to evaluate the radical generation yield of photoinitiators upon UV irradiation using a galvinoxyl radical as an indicator. The absolute quantum efficiency of free radical generation was determined by this method for six different photoinitiators. The yields were in good agreement with the results of theoretical calculations, where the rate of intersystem crossing was revealed to be the determinant step for the resultant radical generation yield. In particular, note that the high quantum yield of initiators could be attainable in the design of a molecule with an efficient intersystem crossing from the first singlet excited state (S1: nπ*) to the second triplet excited state (T2: ππ*).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.