Rheokinetics models for epoxy molding compounds used in IC encapsulation

This study focuses on the development of next generation integrated CAD-based software tools to simulate reactive flow phenomena during plastic encapsulation of ICs. These tools are applicable to both existing production packages and future configurations, such as moulded MCMs, chip scale packages, ball grid arrays, and ultra-thin QFPs. Successful flow simulation for accurate encapsulation process modelling is strongly dependent on input data for cure kinetics and moulding compound rheology. Studies of rheokinetic relations for epoxy systems have investigated model systems rather than commercial materials, mainly because model systems have slower cure kinetics that are better understood than fast (<1 min) commercial resins. In this study, a commercial epoxy moulding compound, Sumikon EME 6300 HN, is explored. Our approach for conversion and rheological data collection on these systems involves initial models of epoxy compounds with reduced catalyst loading rather than standard formulations. As gelation time for these systems is much longer, kinetics and rheological data collection in the pre-gel region is simplified. A Kamal autocatalytic kinetic equation is used to model the change in conversion with reaction time during polymerization of epoxy systems. Differences are noted in the kinetics between systems reacted isothermally at a typical process temperature (~170°C) and those reacted with a slow (<15°C/min) dynamic temperature ramp. Viscosity data for both isothermal and dynamic modes were collected. Use of the Castro-Macosko equation to model pre-gel region viscosity conversion data is presented