The present disclosure is directed to a method of manufacturing a semiconductor structure in which a low-k dielectric layer is formed over a semiconductor substrate. Features can be formed proximate to the low-k dielectric layer by plasma etching with a plasma formed of a mixture of a CO2, CO, or carboxyl-containing source gas and a fluorine-containing source gas. The method allows for formation of damascene structures without encountering the problems associated with damage to a low-K dielectric layer.