Laser direct submicron fabrication by controlling reaction time constant of photoresist

Abstract

This paper focuses on fabrication of submicron structures onto photoresist films by use of a continuous wave (CW) laser. Conventional CW laser fabrication has low accuracy, because the laser beam affects the periphery of a beam exposed area; it is unsuitable for three-dimensional submicrofabrication. Therefore, we have developed a high-accuracy exposure method with CW lasers that use controlling the reaction time constant of photoresists. This method makes it possible to restrict the exposure area by making the response of the photochemical reaction depend on the exposure intensity nonlinearly. In our study, we realized to expose the line pattern having 180 nm minimum width, which is smaller than the focused beam spot diameter, by using the CW laser with wavelength of 532 nm.