Method for forming split gate flash nonvolatile memory devices

Abstract

Disclosed is a method for forming a non-volatile memory device, comprising the steps of: successively depositing a gate oxide and a floating gate material on a semiconductor substrate; depositing and selectively etching a first dielectric on the floating gate material to form a first dielectric pattern; forming a first floating gate oxide on the floating gate material; selectively etching the floating gate material with using the first dielectric pattern as a mask to form a floating gate pattern; forming an insulating layer on the floating gate pattern; etching a portion of the semiconductor substrate between neighboring floating gate patterns to form a trench in the substrate; depositing a control gate oxide on surfaces of the trench; depositing a control gate material to fill the trench and to cover the substrate surface; depositing a second dielectric on the control gate material; selectively etching the second dielectric and the control gate material to form a control gate pattern and a second dielectric layer; selectively removing the control gate pattern to form a source line pattern which extends from the substrate surface exposed in the trench to top surface of the second dielectric layer on the control gate pattern; forming an insulating layer on surface of the source line pattern; and forming source region in portion of the substrate, which is exposed by the source line pattern.