By adding suitable dyes to negative-working CAR resists, even a patterning beyond the usual wavelength range is possible if pulsed lasers with sufficiently high intensity are used for exposure. Relevant laser wavelengths are for example 532 nm and 1064 nm. The dye, which intensively absorbs in the respective wavelength range, is heated during exposure and consequently induces a crosslinking reaction in the resist film. Many users of laser systems do not operate under yellow light conditions. It is thus essential to use photosensitive compounds which are stable under white light and only activated and crosslinked upon exposure to UV light with a wavelength of <300 nm.
Overview Photoresists- Negative