| abstract |
(57) Abstract: A method of depositing and etching a dielectric layer having a low dielectric constant and an etch rate that varies by at least 3: 1 to form a horizontal interconnect. The amount of carbon or hydrogen in the dielectric layer varies with changes in deposition conditions to provide an etch stop layer in damascene applications or a low k dielectric layer that can replace conventional dielectric layers. Dual damascene structures with two or more dielectric layers with dielectric constants less than about 4 allow for deposition in a single reactor, followed by a concentration of carbon: oxygen gas such as carbon monoxide. Are etched to form vertical or horizontal interconnects by varying the thickness of the substrate. The etching gas for forming the vertical interconnect preferably includes CO and fluorocarbon, and the etching gas for forming the horizontal interconnect preferably excludes the CO gas. |