Patent ID: 8940634
Filing Date: 2015-01-27
Classification: H01L

Abstract:
1. A method of forming overlapping contacts in a semiconductor device, the method comprising: forming a first contact in a dielectric layer; etching the dielectric layer, thus forming a recess adjacent to the first contact, and removing a top portion of the first contact by the etching of the dielectric layer while forming the recess in the dielectric layer, wherein a bottom portion of the first contact remains in the dielectric layer after the recess is formed in the dielectric layer, wherein the dielectric layer comprises a top dielectric layer and a bottom dielectric layer, the top dielectric layer and the bottom dielectric layer comprising different dielectric materials, the top dielectric layer being located directly on a top surface of the bottom dielectric layer such that an interface between the top dielectric layer and the bottom dielectric layer acts as an etch stop during the etching of the dielectric layer, such that the top surface of the bottom dielectric layer is exposed by the etching, and wherein the recess is formed in the top dielectric layer; and forming a second contact in the recess adjacent to the bottom portion of the first contact and directly on top of a top surface of the bottom portion of the first contact after removing the top portion of the first contact, wherein the second contact is formed in the recess directly on the top surface of the bottom dielectric layer that was exposed by the etching, such that the second contact does not extend below the top surface of the bottom dielectric layer.