A modified DXRL process for fabricating a polymer microstructure

Abstract

Deep x-ray lithography (DXRL), a fabrication method for producing microstructures with high aspect ratios, plays an important role in the subsequent electroplating process. However, secondary radiation, which is generated during x-ray exposure, damages the resist adhesion to the metal layer. To avoid secondary radiation effects, we modified the conventional DXRL process, changing the sequence of polymer adhesion in the DXRL process and applying thickness losses at the irradiated parts of poly(methyl methacrylate) samples. Optimizing the x-ray exposure, post-exposure relaxation process and development conditions based on a calculated and modified x-ray power spectrum, we fabricated various polymer microstructures and achieved a maximum aspect ratio of 100 with a lateral accuracy of 0.5 µm.