Curing kinetics and optimal cure schedules for underfill materials

The curing reactions and optimal schedules of three promising flip-chip und erfill materials under isothermal and nonisothermal treatments are reported . It is found that curing reactions for three-tested underfill materials ar e autocatalytic, and the cure rate can be well described by the correspondi ng model. The activation energy, the rate constants, as well as two reactio n orders m and n are determined to describe the curing progress. The temper ature dependence of the cure degree for each heating rate is also investiga ted. It is found that the extent of reactions at a given temperature is a f unction of the heating rate. The glass transition temperature for the under fill UF-LI is determined as a function of cure degree. It is found that the glass transition temperature increases with the cure time. (C) 2000 Elsevi er Science Ltd. All rights reserved.