Effect of Processing Parameters and Hygro-thermo-mechanical Stresses on the Reliability of Flip Chip Bonding RFID Tags

The thermal-mechanical reliability of flip chip bonding RFID packaging using low cost materials is investigated. The major processing parameters, such die bonding force, curing shrinkage, are discussed. The reliability tests on the new developed packages show that the electrical resistance of some test samples is degraded and unstable after MSL preconditioning and TMCL tests. In order to investigate the roof causes of such failures, an integrated modeling on the bonding process, temperature cycling and moisture absorption were carried out. 3D parametric FE modeling was setup simulate the die bonding process and adhesive curing process, temperature cycling and hygro-swelling. The experimental and numerical results show that the initial deformation in the metal pads caused by the die bonding and ACA curing shrinkage has an important impact on the electrical performance. Moisture-induced swelling reduces the contact pressure between bumps and the metal pads, resulting in electrical instability. It is also found that moisture-induced corrosion between the contact surfaces may also have important influence on the electrical performance, which is under further investigation.