Lateral capacitor and method of making

A method for forming a semiconductor structure, comprising:

• forming an active device region in and on a semiconductor substrate;
• forming a first dielectric layer of a first dielectric material over the active device region, wherein the first dielectric material has a first dielectric constant;
• forming an etch stop layer over the first dielectric layer;
• forming a second dielectric layer of a second dielectric material over the etch stop layer, wherein the second dielectric material has a second dielectric constant;
• forming a plurality of conductive vias in the first dielectric layer and a plurality of metal interconnects in the second dielectric layer, wherein the second dielectric layer and the plurality of metal interconnects are further characterized as a trench-level portion of an interconnect layer, wherein each of the plurality of metal interconnects is laterally spaced apart from each other and wherein the plurality of metal interconnects form at least one lateral capacitor;
• removing a portion of the second dielectric material from the trench-level portion of the interconnect layer using the etch stop layer such that the removed portion is removed from locations above the etch-stop layer and between laterally adjacent metal interconnects of the plurality of metal interconnects and a remaining portion of the second dielectric material remains within the trench-level portion of the interconnect layer;
• and
• filling the locations between the laterally adjacent metal interconnects from which the portion of the second dielectric material was removed with a third dielectric material having a third dielectric constant, the third dielectric constant being higher than the second dielectric constant.

A semiconductor structure comprising:

• a semiconductor substrate;
• an active device region in and on the semiconductor substrate;
• an interconnect layer over the active device region, wherein the interconnect layer comprises a trench-level portion over a via-level portion, wherein the trench-level portion of the interconnect layer comprises a plurality of metal interconnects, each laterally spaced apart from each other, wherein the trench-level portion further comprises:
• a first dielectric material between laterally adjacent metal interconnects of the plurality of metal interconnects, the first dielectric material having a first dielectric constant;
• and
• a second dielectric material outside the plurality of metal interconnects, the second dielectric material having a second dielectric constant lower than the first dielectric constant.