Patent ID: 8286465

Claim:
A method for selecting die attach adhesives that will auto-flow and self-fillet when disposed between two substrates comprising: providing a die attach adhesive comprising a resin and a filler; applying an initial shear stress to the die attach adhesive until it turns from a viscoelastic solid to a liquid, for a time duration ranging from two to ten minutes at 25Â° C.; equilibrating the die attach adhesive, for a time duration ranging from two to ten minutes at 25Â° C.; applying shear stress to the die attach adhesive by ramping up from 0.1 Pa to 200 Pa, for a time duration ranging from two to ten minutes at 25Â° C. and then by ramping down from 200 Pa to 0.1 Pa, for a time duration ranging from two to ten minutes at 25Â° C., to generate a yield stress rheological curve; determining the yield stress value from the yield stress rheological curve; and selecting those die attach adhesives that have a yield stress value between 1.8 Pa and 10 Pa.