Solder bump creation by using droplet microgripper for electronic packaging

A simple and effective method to create solder bumps by using a droplet microgripper for electronic packaging is described. A reusable droplet microgripper was realised simply by patterning a Teflon amorphous fluoropolymer on a glass substrate to make a 5 × 5 hydrophilic opening site array of 300 μm-diameter circles and 600××m pitches. The microgripper was used to self-arrange solder balls of 300 μm diameter on its wetted sites. After transferring the solder balls to a flux-coated soldering substrate by an alignment process, solder bumps were successfully created on the corresponding solder ball lands through a reflow process.