Optimization of Thick Negative Photoresist for Fabrication of Interdigitated Capacitor Structures

Investigations were conducted in the optimization of a lift-off photolithography technique using thick negative photoresist (PR) NR9-8000 to achieve and optimize micron-scale interdigitated capacitor (IDC) structures by lift-off process for use in high-frequency electrical characterization measurements. Target feature resolution was in the range of 3 20 m, with PR thickness in the range of 6 20 m. Systematic deviations were made from manufacturer-recommended PR processing conditions to investigate a processing-structure relationship for optimizing of IDC fabrication including PR response to manipulation of substrate material, spin-speed, postexposure bake, exposure dose, and development process conditions. Postexposure bake temperature was found to be the most sensitive and critical parameter for the optimization of PR structures.
The original document contains color images.