Dendritic material as a dry-release sacrificial layer

A dry-release process using highly structured dendritic material, specifically, hyperbranched polymers (HBP's), has been developed. A particular HBP under study, known as HB560, has been characterized and successfully integrated with microelectromechanical systems processing. An array of electroplated nickel cantilever beams 100 /spl mu/m/spl times/100 /spl mu/m /spl sim/1000 /spl mu/m in length has been successfully fabricated and dry released. The required release time is 10 min at 600/spl deg/C in O/sub 2/. Single open-ended microchannels were fabricated to determine the etch time and tunneling length achieved using HB560 as a sacrificial material. The time improvement for the sacrificial release is on the order of 40/spl times/ compared to standard HF wet-etch processes. Etch lengths of 1 cm have been successfully demonstrated with a sacrificial layer aspect ratio of 1600. A photosensitive version of the dendritic material has also been synthesized and characterized to reduce the process steps.