Large-area silicon electronics using stretchable metal interconnect

A post-processing module for converting monolithic silicon electronics into a large area system is presented. The concept is based on the previously demonstrated capability of a mesh-patterned, free-standing copper interconnects to be plastically stretched [1]. When such stretchable mesh interconnect is added to a functional silicon wafer, closely spaced array of IC dies can be expanded into a large-area system. Either evaporated aluminum or electroplated copper are investigated as the metal used for deformable interconnect. Optimization of the interconnect geometry and proper positioning of the anchoring points is used to control the stress distribution and to maximize the stretching ratio. The initial fabrication and measurement results with aluminum interconnect show that a 1D stretching ratio for 3times3 mm² silicon islands of more than 15 can be achieved and that the ratio of stretched over unstretched area (2D array) of more than 200 is feasible.