DEVELOPMENT OF A FAST AND HIGH-RESOLUTION E-BEAM PROCESS FOR THE FABRICATION OF X-RAY MASKS WITH CD OF 0.15 MU-M

In this paper it is presented a study on the process optimization for an e-beam sensitive commercial chemically amplified negative resist, the Shipley SAL 601-ER 7, used for fabrication of gold X-ray masks with CD down to 0.15 mum and complexity equivalent to that of 1 Gbit DRAM. The study includes the effect of pre-baking and post-baking thermal processes on resolution, exposure latitude and resist contrast. It is demonstrated that by using 105-degrees-C temperature for pre- and post-exposure baking, 0.15 mum lines spaced of 0.15 mum can be achieved with an aspect ratio exceeding 4. Resist process is also successfully exploited for fabrication of a gold additive x-ray mask.