Vertical Interconnect Technology for Enlarging Capacity on Micro Solid Thin Film Rechargeable Battery

A vertical interconnect technology for stacking micro solid thin film batteries (STFB) in IoT devices is proposed. This technology consists of stacking glass substrates with a layer of solid thin film battery, drilling by laser machining, filling the holes with solder to connect the stacked batteries, and dicing the stacked wafer to 1×1 mm micro stacked batteries. In this work, various metals are evaluated to identify the appropriate electrode drilled with glass and resin. The effects of the laser wavelength are also investigated.