Abstract
A novel way by employing JSR THB-430N negative tone resist to replace SU-8 resist for ultrathick plating mold fabrication is proposed in this paper. SU-8 is a common resist utilized for fabrication of high aspect ratio micro-structures. However, it is well known that SU-8 is hard to strip when served as a plating mold, especially in ultrathick and high aspect ratio regions. In contrast, cured THB-430N resist proposed in this paper can be softened in acetone and then easily striped by THB-S1 stripper without damage of micro-structures. Current approach using THB-430N resist can reach a structure height of 1.4 mm and an aspect ratio at least 5. Low power ultrasound has been employed to eliminate undercut problem and reduce developing time [Microsyst. Technol., in press]. Through-mold plating and PR striping of 1.4 mm thick THB-430N resist has been successfully demonstrated, and the plated thick copper structures show good structure integrity.