Reprocessable, Creep-Resistant and Fully Biobased Thermosets for Power Semiconductor Packaging.

Amid rapid advances in third-generation semiconductors and holistic life-cycle management, thermoset-based packaging materials are evolving toward high-temperature resistance, eco-friendliness, and reprocessability. However, beyond the pursuit of recyclable carbon, thermosets face a fundamental trade-off between recyclability and high-temperature reliability, which poses a significant challenge. Herein, we report a thermally activated mechanically constrained adaptive network, in which side-group transesterification at nanodomain boundaries enables adaptive reorganization without disrupting the connectivity of the network. This reprocessable network (DHBEP/PF/AE), constructed by tetrafunctional epoxy/phenolic/active ester resins with 100% biomass content, achieves a high Tg (181°C) and excellent high-temperature creep resistance as high as 170°C. Critically, a reprocessable epoxy molding compound is fabricated based on DHBEP/PF/AE, which successfully packages SiC chips via TO-247 method and passes moisture sensitivity level-3 test. This work resolves the classic contradiction between recyclability and reliability of dynamic thermosets, providing a solution for the biomass-based conversion and reuse of vast quantities of semiconductor packaging materials.