Patent ID: 7115506

Claim:
A method of fabricating a contact structure for an integrated circuit, comprising: providing a semiconductor substrate having a lower bulk insulator layer thereupon, a dielectric layer upon the lower bulk insulator layer, and a conductor layer upon the dielectric layer; forming a dielectric layer on the lower bulk insulator layer; forming a conductor layer upon the dielectric layer; forming a first insulator layer upon the conductor layer; forming a second insulator layer upon the first insulator layer, the second insulator layer having a top surface and having a thickness greater than that of the first insulator layer; selectively removing the first and second insulator layers so as to form a opening defined by the lower bulk insulator layer, the dielectric layer, the conductor layer, and the first and second insulator layers, the opening terminating at a bottom surface within the lower bulk insulator layer above the semiconductor substrate; forming a sleeve insulator layer upon the top surface of the second insulator layer and within the opening so as to make contact with each of the lower bulk insulator layer, the dielectric layer, the conductor layer, and the first and second insulator layers; removing the sleeve insulator layer from the bottom surface within the lower bulk insulator layer above the semiconductor substrate, from the top surface of the second insulator layer, such that the sleeve insulator layer has a terminus at an interface between the first and second insulator layers, and extends to an opposite terminus that is above the semiconductor substrate, within the lower bulk insulator layer, and below the dielectric layer; and removing material of the lower bulk insulator layer to expose a contact on the semiconductor substrate.