PURPOSE: To package a PROM having a fuse without decreasing the writing yield and the reliability by sealing a resin layer to allow a cavity to remain in the hole of an insulating film part on the fuse.

CONSTITUTION: A polycrystalline silicon wire 29 formed at a PROM partly has a narrow fuse 28. First, the PROM is covered entirely with a protective insulating film 32. Thereafter, the film 32 on the fuse 28 is opened at a hole 37. Then, a spin-ON glass film is formed at the periphery of the hole 37, and a refractory organic macromolecular film 35 is then covered on the overall surface. A hole of small diameter is formed at the film 35 corresponding to the hole 37, and the spin-ON glass film is dissolved and removed through the hole. Thereafter, the entire element is molded with epoxy resin 40. In this case, since the inlet side of the hole 37 has a small diameter, the resin does not enter into the entire hole 37, but a cavity 39 is formed.