A NOVEL METHOD OF STEREOLITHOGRAPHIC ALIGNMENT FOR MEMS STRUCTURES
Arnab Choudhury and Peter J. Hesketh
Georgia Institute of Technology, US
Keywords: Stereolithography, alignment
In recent years there has been a fair amount of interest in integration of stereolithography with MEMS devices for purposes of packaging of microfluidic devices or to build new MEMS devices that are able to leverage from the high aspect ratio 3D structures that can be built using stereolithography (SLA). However little success has been possible in fabrication in which feature size or dimensional tolerances are very small and/or where accurate alignment with devices fabricated by micromachining of silicon is required. This work seeks this address the issue of alignment with microdevices fabricated by traditional MEMS techniques.
In the current work we have attempted to ensure more accurate alignment of the stereolithgraphically fabricated feature with the microfabricated device by extending the principle of lithography used in microfabrication to the integration of SLA structures to the silicon die. A mask was created in a 3D Systems SLA with a build resolution of 50µm. The negative curing stereolithographic photopolymer SL5510 was spun coated onto the wafer and alignment was done on a conventional mask aligner. Adhesion between the silicon die and the SLA mask was ensured by prolonged exposure at 365nm for 1000s. After this a post cure further hardens SLA parts.
NSTI Nanotech 2003 Conference Technical Program Abstract