TW279268B - Fabrication method of mask ROM - Google Patents

Abstract

A fabrication method of mask ROM, that is applicable to implement mask ROM with the first-type semiconductor substrate, comprises the steps of: forming multiple masking material along one first direction on the above semiconductor substrate; forming polysilicon layer on semiconductor substrate between the above masking material; doping the second-type dopant to the above polysilicon layer, and through the above polysilicon layer diffusing to the above first-typesemiconductor substrate to form the second-type doped area; forming metal silicide on the above polysilicon layer, and making the above metal silicide, polysilicon and doped area become bit line of the above mask ROM; removing the above masking material; forming gate oxide on the above bit line and semiconductor substrate; forming multiple word lines along the second direction with determined angle to the first direction on gate oxide, and forming trench on word line located between the above bit lines; through the above trench doping the first-type dopant to the first-type semiconductor substrate between the above second-type doped area to perform coding.