Method for forming an inter-metal dielectric layer

摘要

A method for forming an inter-metal dielectric layer without voids therein is described. Wiring lines are formed on a provided substrate. Each of the wiring lines comprises a protective layer thereon. A liner layer is formed over the substrate and over the wiring lines. An FSG layer is formed on the liner layer by using HDPCVD. A thickness of the FSG layer is about 0.9-1 times a thickness of the wiring lines. A cap layer is formed on the FSG layer using HDPCVD. A thickness of the cap layer is about 0.2-0.3 times a thickness of the wiring lines. An oxide layer is formed on the cap layer to achieve a predetermined thickness. A part of the dielectric layer is removed to obtain a planarized surface.