Method of manufacturing semiconductor device having reduced contact resistance between access transistors and conductive features

Abstract

The present disclosure provides a method for manufacturing a semiconductor device. The method includes providing a substrate comprising one or more isolation features defining active regions; forming at least one access transistor comprising a plurality of impurity regions, wherein the impurity regions are disposed in the substrate; depositing a dielectric layer to cover the access transistor; forming a first contact hole through the dielectric layer to expose the associated impurity region; forming a sacrificial liner in the first contact hole; removing a portion of the substrate exposed through the first contact hole and the sacrificial liner to form a second contact hole connected to the first contact hole; and forming a conductive feature in the first and second contact holes.