Self-Filleting Die Attach Paste

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 shear stress to the resin and filler from 0.1 Pa to 200 Pa and then reducing the shear stress from 200 Pa to 0.1 Pa, within ten minutes and at 25° 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.