Silicon projection mask-making technology for e-beam lithography

Abstract

We have developed a new method to manufacture with a high degree of accuracy silicon (Si) stencil mask (or projection mask) which provides stability and is also adaptable to electron beam (EB) cell projection lithography that has a high throughput. The important processes are the technologies of dry etching for forming an aperture pattern, wet etching for forming the membrane pattern area, and the development of metal material that adapts EB lithography. At this time, when each process combines, adaptation is required that does not cause technical problems, and also it is important to consider the stability of the whole process and the necessity to do all processes at as low temperature as possible. We succeed in doing it under at 100 degrees, upon investigation after testing the EB exposure with the stencil mask, which was manufactured by using a productive method that was already developed, it was found to have a resolution under 0.2 micrometer. By development of this, stable fabrication of the stencil mask that was one of the key technology of EB cell projection lithography became practical. Also it was considered that it could contribute to the new generation of ultra-large-scale-integration (ULSI) product technology in the future.