TAB Versus Wire Bond-Relative Thermal Performance

There has been a resurgence of interest in tape automated bonding (TAB) as a method of interconnection between the chip and the substrate in recent years. Proponents of TAB have claimed superior thermal performance for TAB bonded packages compared to wire bonded packages. However, little experimental evidence for such claims existed. Described are experiments and theoretical modeling done on Wire bonded and TAB bonded packages under free air, forced air, and conduction cooling for various die attach methods. For packages mounted on cold plates where
\theta
jc
(i.e., internal thermal resistance of the package) dominates the thermal behavior of the package, TAB bonded packages were found to have slightly lower thermal resistance than wire bonded packages. For PCB- and socket-mounted packages dissipating heat in natural or forced-air cooling where
\theta
ca
(i.e., external thermal resistance) dominates the thermal behavior of the package, TAB bonded and wire bonded packages were found to have about the same thermal performance.