Patent ID: 6190974
Filing Date: 2001-02-20
Classification: H01L

Abstract:
A method of fabricating a mask read-only memory (mask ROM) for forming a circuit having a mask ROM and other types of memory or logic devices therein, comprising the steps of:providing a substrate having a plurality of bit lines, a plurality of word lines, an inter-layer dielectric layer, an inter-metal dielectric layer and a metallic interconnect pattern;performing a photolithographic operation to form a coding mask for code implantation over the inter-metal dielectric layer;etching the inter-metal dielectric layer and the inter-layer dielectric layer to form a contact opening leading to a device using the coding mask as an etching mask;performing an ion implantation to implant ions into coding positions of the substrate of the device;removing the coding mask; anddepositing dielectric material to form a dielectric layer inside the contact opening.