a reusable packaging material for semiconductor devices . the semiconductor device package is formed from a thermoplastic resin . the resin has good fluidity and good adhesion . the new package is recyclable because the thermoplastic resin hardening process is reversible . the new package has sufficient mechanical strength and adhesion to seal a semiconductor device . a thermoplastic material for sealing a semiconductor element is characterized by 4 . 5 × 10 − 5 or less linear thermal expansivity at about 150 - 200 . degree . c .