Method of transforming otp rom manufacturing process into rom manufacturing process

Abstract

A method of transforming the OTP ROM manufacturing process into the ROM manufacturing process comprises a check step for checking the OTP ROM manufacturing process to determine which manufacturing step is already performed. If the step of depositing the polysilicon layer, acting a control gate, has already been performed, a standard OTP ROM manufacturing process is then performed. Thereafter, a coding energy is performed, in which the coding energy is about 50 KeV higher than a standard coding energy. If the step of depositing the polysilicon layer, acting a control gate, has not yet been performed, then the coding energy is about a standard coding energy. Whatever step the ongoing OTP ROM manufacturing process is on, the present invention can transform the OTP ROM manufacturing process into the ROM manufacturing process to produce ROM by the direct implanting step. It isn't necessary to redesign the masks. The size of the OTP ROM is approximately the same as the ROM so that no die surface is sacrificed.

Dependencies are inferred from the claim text.