Epoxy adhesive and process enhancement on delamination related IC and packaging reliability problems: An evaluation study I

The surface modification of bare Cu leadframe surfaces by heat treatment, or plasma cleaning, or the coupling of both treatments, either before die-attach, encapsulation, or before both processes, as a means to combat package reliability issue especially delamination of mode I & II were investigated. The effectiveness of these treatments were gauged with contact angle measurements: before, after and during post treatment ageing period of 24hrs. Prototype units were assembled and subjected to pre-condition of 85degC/85RH for 168hrs follow-up with 3 times reflow (peak temperature at 260degC for 20-40sec, MSLI). CSAM is used to interpret the performance of the epoxy adhesion on the pre-treated surfaces. The treatments were found to be effective in overcoming the delamination of mode I & II.