Use of novel photoresists in the production of submillimeter-wave integrated circuits

A new technique is reported for micro-machining millimeter and submillimeter-wave rectangular waveguide components using an advanced thick film UV photoresist known as EPON TM SU-8. The recent introduction of this resist has been of great interest to the millimeter-wave and terahertz micro-machining communities, as it is capable of producing features up to 1 mm in height with very high aspect ratios in only a single UV exposure. It therefore represents a possible low-cost alternative to the LIGA process. S-parameter measurements on the new rectangular waveguides show that they achieve lower loss than those produced using other on-chip fabrication techniques, they have highly accurate dimensions, are physically robust, and cheap and easy to manufacture.