Thermally cleavable epoxy resins for electronic and optoelectronic applications

Owing to their excellent electrical properties, mechanical strength and processability, epoxy resins are widely adapted in the field of electronics. Epoxy in the nature of thermosetting, however, would produce intractable polymeric materials after being cured. Intractability is considered disadvantageous in terms of reworkability. To achieve reworkability, two types of epoxy resins with built-in thermally cleavable functionalities, namely thermally degradable and thermally reversible groups, were designed and synthesized. The thermally degradable type resin (TDR) was formulated into an underfill formulation for flip-chip technology. The thermally reversible type resin (TRR) was put in the adhesive formulation for potential optoelectronic applications. Experiments showed the easiness of chip removal and the cleanability of the residue.