Novel technique for high aspect ratio high resolution patterning of membranes

A technique of x-ray exposure through membrane is developed for fabrication of self-aligned gold patterns on both sides of membranes and multiple layers of self-aligned structures. The final structures have aspect ratio several times higher than the ones obtained in single photoresist layer exposure. This is important for sub-0.2 μm patterns when the photoresist collapse prevents fabrication of high aspect ratio structures. Fresnel zone plates (FZPs) for hard x-ray microscopy are fabricated using these techniques. The final FZPs have total thickness of gold pattern of 1.6 μm, and the smallest linewidths in FZP pattern is 0.15 μm. At this critical dimension level, both developed techniques demonstrate good results.