Novel Method of Thermal Epoxy Curing Based on Photogeneration of Polymeric Amines and Negative-Tone Image Formation

Abstract

Polymeric amines generated by UV-induced electron transfer in polymeric quaternized tetraalkylammonium borate salts are found suitable for the thermal cross-linking of epoxides where nucleophilic attack on the epoxy ring is favorable. A cross-linked polymer network insoluble in organic solvent becomes the basis of a negative-tone photoimaging system. Sensitivity and resolution parameters have been evaluated by atomic force microscopy (AFM). Addition of reagents containing hydroxyl moieties to a film containing both the polymeric amine precursor and epoxide improves sensitivity more than 3-fold manifesting chemical amplification due to the catalytic nature of the cross-linking process.

Base-amplifying silicone resins with photobase-generating side chains and their application to negative-working photoresists

“…The BA units in these resins were found to be decomposed abruptly after an induction period, which indicated autocatalytic decomposition triggered by amines generated from PBG units. High photosensitivity, 8.1 mJ cm 22 , was accomplished using a film of the resin containing 10% PBG units with PEB for 30 min at 100 C. To our great delight, the potential ability of the baseproliferation reaction was clearly shown by comparison between resins having blank/PBG or BA/PBG units, which showed about 490 times enhancement of photosensitivity. Finally, a negative-tone relief image with 4 3 10 mm lineand-space pattern was successfully fabricated, which was comparable to a conventional acid-amplifying resist.…”

“…Photosensitive polymers are indispensable for this process as photoresists to protect metal surfaces while being subjected to an etching process. [1][2][3][4][5] To accomplish high photosensitivity, various chemical amplification systems have been developed in which photogenerated acid 6,7 or base [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] catalyses a chemical reaction in a resist film. While photosensitive materials based on basecatalysed reactions have merit for preventing erosion of metallic substrates, photobase generators generally have low quantum yields, which leads to low photosensitivity.…”

4-(Bromomethyl)benzophenone

“…Water-soluble photoinitiators which can be used in watersoluble UV-cured coatings have attracted a great deal of interest over the last few years (Mejiritski et al, 1997). The title compound, (I), is an important intermediate for the synthesis of water-soluble photoinitiators (Green & Green, 1989) and we report its crystal structure here.…”

Sensitivity Enhancement of a Photocuring Material by Base Amplifiers.

“…systems relying on the photochemical liberation of a basic species [1][2][3][4] have received far less attention probably due to relatively low quantum yields of photobase photogeneration, leading to the low photosensitivity.…”