The photomask used in the lithography process has the important role of transferring circuit pattern images onto the photoresist. To meet the demand for increased photomask manufacturing throughput, the current density of electron beam (EB) writers has been increased. EB exposure locally increases the resist temperature on the mask substrate depending on various factors, including current density, shot size, and writing order. Resist sensitivity increases with irradiated resist temperature, a phenomenon known as “heating effect”. In this study, we reported the cause of the temperature-dependent sensitivity increase in a polyhydroxystyrene-type chemically amplified resist. The experimental results, including acid generation efficiency measurements and pulse radiolysis with changing temperature, suggest that the heating effect is mainly caused by the deprotonation efficiency associated with the radical cation of the base polymer.

A new family of emissive donor–acceptor–donor (D-A-D) compounds has been developed by introducing two electron donors into the 7,8-diaza[5]helicene core as a novel helical electron acceptor. The X-ray crystallographic analyses revealed the uniquely twisted and helical structures of these compounds in the solid states. Notably, some D-A-D compounds developed herein display distinct mechanochromic luminescence (MCL) in the solid state, and a D-A-D helicene shows circularly polarized luminescence (CPL) with a relatively high luminescence dissymmetry factor g lum of ca. 10–3. Time-resolved spectroscopic analysis revealed the aspects of thermally activated delayed fluorescence characters of the helicenes. Furthermore, the emissive helicenes were applied to organic light-emitting diodes as emitters.

Efforts are being focused on increasing the power of extreme ultraviolet (EUV) light sources used in semiconductor manufacturing to increase the throughput. As a result, the investigation of the effect of high power sources on resist materials is a critical issue. A chemically amplified resist (CAR) and a non-CAR were irradiated with 13.5 nm EUV high-flux pulses from a soft X-ray free-electron laser (FEL). In the non-CAR, the positive-tone resist (ZEP520A) exhibited lower sensitivity at high irradiation densities, while the negative-tone resist exhibited a higher sensitivity. In addition, the dose rate did not considerably affect the sensitivity of the CAR.

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