Moisture resistance of epoxy resin used for extremely low profile IC modules

Since IC cards and TAB (tape automated bonding) represent extremely-low profile IC modules, it is difficult to realize packages of these types with high moisture resistance. The authors evaluate three different types of epoxy resins (pellet, liquid, and solvent type) that suit automated and inline processes. They also consider problems regarding reliability and process control. Moisture resistance is shown to decrease in epoxy resins of the pellet, solvent, and liquid types, in that order, because the liquid epoxy resin liberates a large quantity of Cl ions due to the production process used for the epoxy resin and the design of the composites. The pellet-type resin contains many fillers, and, as a result, moisture diffusion into the bulk resin is low. In the case of the liquid resin, it is important to minimize the moisture absorption during the time between coating and curing