| 摘要 |
PURPOSE:To simply convert a malfunction generated due to a cause which cannot be avoided during manufacturing to a satisfactory product and to improve the yield of an electrically rewritable nonvolatile memory by irradiating the memory with ultraviolet-rays to set the memory after the manufacture to an enhancement state. CONSTITUTION:A semiconductor storage device after the manufacture is irradiated with an ultraviolet-rays to provide a protective film 12 of a neutral state of a floating gate 10 charged to a positive. As the film 12 for transmitting the rays, an oxide film used in an EPROM is employed. Since the oxide film has inferior moistureproof as compared with a nitride film, an ultraviolet ray transmitting nitride film which transmits certain degree of the rays is used by altering the refractive index of the acid nitride film mixed with oxygen and nitrogen or normal nitride film. In these cases, its ultraviolet transmission rate is lower than that of the oxide film, and it is necessary to irradiate nitride film with the ultraviolet-rays for a several to several tens of times longer period compared with the case of the oxide film, but since it is used after completion of the product, there is no large problem. |
