A patterning of the conductive coating Electra 92 is to a certain extent possible if the following procedure is used:
A negative resist (e.g. AR-N 4340) is coated onto the substrate, exposed, and developed. The exposure dose should be chosen as small as possible to provide the desired slight undercut which supports the later lifting. Onto these structures, Electra 92 is coated. Thin (50 – 200 nm), high-quality Electra films can be obtained through an optimisation of the spin speed. Negative resist structures are then removed (lifted) by carefully rinsing with acetone and, if required, with ultrasonic support, while Electra 92 remains unchanged. A small increase of the film thickness at the edge of Electra structures may occur which should however not impair the quality. This procedure allows the manufacture of directly conductive samples.
Overview E-beam Other Resists