SEMICONDUCTOR MEMORY

PURPOSE:To erase memory comparatively simply, reducing cost, and to execute a writing test for ensuring reliability simply and properly without generating large waste by disposing fluorescent substance to a section covering at least a memory section in a semiconductor chip for an EP-ROM. CONSTITUTION:A semiconductor substrate to which memory circuits are integrated and formed-that is, a semiconductor chip 1, is sealed into a light-screening package 5 under the state in which it is mounted onto a lead frame 2. A fluorescent substance 6 is arranged to a section covering at least a memory section in the semiconductor chip 1 in the light-screening package 5. Consequently, when the fluorescent substance 6 is shaped, the internal fluorescent substance 6 is excited by transmitting X-rays 21 by projecting X-rays 21 from the outside of the package 5. Ultraviolet rays 22 for erasing are radiated from the fluorescent substance 6 by the X-ray excitation, and the memory section is irradiated by ultraviolet rays. Accordingly, informations written to the memory section can be erased by ultraviolet rays by package structure having no introducing window for beams for erasing.