Evaluating the influence of post-mould cure and additives on the viscoelastic properties of a low stress epoxy mould compound

This work investigates the influence of post mould cure (PMC) duration on the viscoelastic properties of a low stress, epoxy mould compound. Results show glass transition increases while modulus measured at room temperature decreases with increasing PMC duration. Glass transition typically increases with increasing PMC as cross-linking density increases. Modulus is not expected to decrease with increased cross-link density. It is postulated that progressive attachment of silicone particles to the cross-link network of the encapsulant is active during PMC. The net effect of the attachment of silicone particles to the cross-linked network and increased cross-link density as a result of residual cure is a decrease in modulus with increasing post mould cure.