Planarization in an encapsulation process for thin film surfaces

摘要

A process to reduce step heights in planarization of thin film carriers in an encapsulation system. The improvements include using an adhesive tape having a thinner adhesive thickness and a stiffer tape for the film sealing the encapsulant on the carrier to result in a low step height surface transition between the carrier and the cured encapsulant. The composition of the encapsulant is modified to reduce the shrinkage upon curing of the encapsulant. The encapsulant may include an absorbent that absorbs the irradiation and cause the top surface to harden first compared to the bulk of the encapsulant, and/or a gas-emitting additive that creates gaseous products that expand upon irradiation to thereby reduce the shrinkage of the encapsulant upon curing. Alternatively, irradiation at very low incidence angle relative to the top surface of the encapsulant causes the top surface to harden before the bulk of the encapsulant.