Disclosed is a method that uses a high-temperature polymer wafer media to process ultra thin wafers through a solder paste machine and a high-convection reflow oven. Benefits include a solution that safeguards the ultra thin wafers from scratches, cracks, and mishandling.

Background

Many processing issues (e.g. cracking, non-wets, bump uniformity, etc.) are associated with the bumping and reflowing of ultra thin wafers through a solder paste printing machine and a high- temperature, high-convection oven.

To solve these problems, wafers are placed in a solder paste machine by hand with a pair of tweezers, then paste printed; however, this process scraps 50% of the wafers due to cracking and mishandling. The remaining wafers are then removed by hand, placed on a carrier, taped down with thermal tape, and sent through a reflow oven. This process flow can also cause scratching or cracking on the wafers.

General Description

The disclosed method is a high-temperature media that keeps wafers level and in place, and is able to withstand high-temperatures in the shape of a wafer. The wafer media is ported for vacuum and supplied with a vacuum line once on the solder paste print machine to keep wafers flat when they are processed. This media is also used to process the wafers through a reflow oven after they have been stencil printed with solder paste. A top interconnecting retaining ring is placed on top of the med...