Due to its excellent structural quality, resist SU-8 is in principle suitable for the fabrication of galvanic components, but the extremely difficult removal of resist structures after electroplating argues against this application. Our negative resist AR-N 4400-50 (CAR 44) which can also be used for layer thicknesses of up to 100 µm is however relatively easy to remove after the process.
In cooperation with United Monolithic Semiconductors GmbH, Ulm, it was possible to optimise the processing method for AR-N 4400-50 such that 30 µm-structures with vertical edges were generated. Exposure and development regime were precisely adapted to the technological requirements. Electroplating with this optimised resist finally yielded metal structures with a desired thickness of 18 μm.
Detailed view of the metal structure, confirming the vertical edges of AR-N 4400-50
Metalized structures after resist removal
The successful evaluation of our development at one of our largest customers was the reason for us to select AR-N 4400-50 as resist of the month of July.