Integrated-Ultra High Density (iUHD) die thinning and handling

Draper Labs IR&D 2007Motivation: This project is driven by an increasing demand for vanishingly small electronic devices especially for intelligence operations. The use of thinner die directly translates into lower internal stresses within the chips.

iUHD die thickness goalForty microns (40 um) or less is the die thickness goal.

Thinning is currently envisioned as a two step process. #1. Coarse thinning - Bulk silicon is removed from the back of each die using a lapping process with diamond slurry.

#2. Fine thinning – The remainder of silicon is removed using cmp to eliminate stress raising scratches and provide a mirror-like surface.

Unique carrier fixture for die thinning is requiredThe goal is to develop a thinning process that will allow dies to be thinned, inspected, and applied to the substrate as a group.

Device Variables

• Die range in size from about 12 mm square to about 0.5 mm square.

• Die have unique topography and surface dielectric coating Common Defects:•Edge chips•Sub-surface damage•Scratches•Curled/Wavy die•Particulate embedded in die face