Micro devices integration with large-area 2D chip-network using stretchable electroplating copper spring

Abstract

This study presents a large-area multi-devices integration scheme using stretchable electroplated copper spring. Each device is located on the silicon-node of a 2D chip-network distributed, which are mechanically and electrically connected to surrounding devices by stretchable copper spring. The springs stretch and expand the functional devices by several orders of magnitude area forming a variable-density network of interconnected devices. Advantages of this approach include: (1) using existing process technologies and materials for semiconductor in large-area applications, compatible with foundry fabrication processes; (2) stretchable electroplated copper springs with large maximum strain act as both mechanical and electrical connections between devices; (3) silicon-nodes act as hubs for device implementation and integration; and (4) the chip-network can be applied to 2D-curved (spherical) surfaces. The proposed expandable network using stretchable springs integrated with multiple devices has been implemented and tested.