Solder Pump Technology for Through-Silicon via Fabrication

We present a solder pump method that injects conductive material into a device wafer to form low-resistance through-silicon vias (TSVs). Building on previous work that exploits the Gibbs-Thomson effect, this pump geometry uses a reusable wafer set to produce a pattern of U-shaped reservoirs into which solder balls are loaded. After introduction of the device wafer with a corresponding pattern of through-wafer-etched holes, reflow results in the complete transfer of the solder from the reservoirs into the device structure to produce the vias. This approach forms the basis of a rapid low-cost batch-fabrication process for TSVs.