Three level interconnect process for manufacture of integrated circuit devices

Claim 1

A method of making an insulated gate field effect transistor and a cross-over connection in an integrated circuit comprising the steps of: (a) selectively growing thick field oxide using an oxidation mask to provide an enclosed surface area on said face for the transistor and a defined area for the cross-over connection, (b) introducing N-type impurity into said defined area to produce a conductive region and into the enclosed surface area to produce source and drain regions of an N-channel transistor leaving a space between said source and drain regions to create a channel, (c) depositing a layer of conductive material on said face over a thin gate insulator and patterning the conductive material to provide a gate of an N-channel transistor in said enclosed surface area in the space between the source and drain regions but leaving a gap between such gate and source and drain regions, the conductive material after patterning also extending across said conductive region, (d) and implanting N-type impurity into the enclosed surface area, self-aligned with said gate, adjacent said source and drain regions, to bridge said gaps.

Claim 2

A method of making an insulated gate field effect transistor and a cross-over connection in an integrated circuit comprising the steps of: (a) selectively growing thick field oxide using an oxidation mask to provide an enclosed surface area on said face for the transistor and a defined area for the cross-over connection, (b) introducing N-type impurity into said defined area to produce a conductive region and into the enclosed surface area to produce source and drain regions of an N-channel transistor leaving a space between said source and drain regions to create a channel, (c) depositing a layer of conductive material on said face over a thin gate insulator and patterning the conductive material to provide a gate of an N-channel transistor in said enclosed surface area in the space between the source and drain regions but leaving a gap between such gate and source and drain regions, the conductive material after patterning also extending across said conductive region, (d) and implanting N-type impurity into the enclosed surface area, self-aligned with said gate, adjacent said source and drain regions, to bridge said gaps.

Claim 4

A method of making an insulated gate field effect transistor and cross-over connections in an integrated circuit comprising the steps of: (a) introducing impurity of one type into a first surface area of a face of a semiconductor body of opposite type to produce source and drain regions of a transistor and also into a second surface area of the face to produce a conductive region, (b) depositing a layer of conductive material on said face over a thin gate insulator and patterning the conductive material to provide a gate of the transistor on said first surface area spaced from the source and drain regions by gaps, and also to provide a conductor crossing over said second surface area, (c) and implanting said one type impurity into said first surface area, self-aligned with said gates, adjacent said source and drain regions, to bridge said gaps.

Claim 5

A method of making an insulated gate field effect transistor and cross-over connections in an integrated circuit comprising the steps of: (a) introducing impurity of one type into a first surface area of a face of a semiconductor body of opposite type to produce source and drain regions of a transistor and also into a second surface area of the face to produce a conductive region, (b) depositing a layer of conductive material on said face over a thin gate insulator and patterning the conductive material to provide a gate of the transistor on said first surface area spaced from the source and drain regions by gaps, and also to provide a conductor crossing over said second surface area, (c) and implanting said one type impurity into said first surface area, self-aligned with said gates, adjacent said source and drain regions, to bridge said gaps.