Overcoming SU-8 stiction in high aspect ratio structures

Deep X-ray lithography is a well known technique used for making high aspect ratio structures (HARS). However, well known difficulties arise in the creation of some HARS; adhesion of the developed resist structures to the plating base commonly fails, and when resist structures are densely packed features can clump together. This in turn can exacerbate adhesion failure. The problem of clumping is sometimes known as stiction. In this paper we describe an idea involving a low dose UV second exposure that can help overcome stiction in certain designs and thus promote adhesion and the retention of the designed structure.