Hybrid hard mask for damascene and dual damascene

摘要

A method of forming damascene vias or dual damascene wires. The method includes using a patterned two layer hard mask wherein the patterns in the lower and upper hard mask layers are formed using a reactive ion etch process. Openings are then formed in the interlevel dielectric layer under the two layer hard mask using a second reactive ion etch process which also removes and the upper hard mask layer. The lower hard mask layer is then removed with a wet etch. Further processing completes forming the damascene vias or dual damascene wires.

主权项

1. A method, comprising:
forming a damascene conductor in a dielectric layer on a semiconductor substrate and a dielectric barrier layer on a top surface of said damascene conductor and a top surface of said dielectric layer; forming a dielectric stack on a top surface of said dielectric barrier layer, said dielectric stack comprising an interlevel dielectric layer on a top surface of said dielectric barrier layer; forming a lower hard mask layer on a top surface of said dielectric stack and an upper hard mask layer on a top surface of said lower hard mask layer; using a first reactive ion etch selective to said upper and lower hard mask layers over said interlevel dielectric layer, forming a via opening through said upper hard mask layer and said lower hard mask layer to a top surface of said dielectric stack; using a second reactive ion etch selective to said upper hard mask layer and said interlevel dielectric layer over said dielectric barrier layer, extending said via opening through said interlevel dielectric layer to said dielectric barrier layer; removing said lower hard mask layer using a wet etch; using a third reactive ion etch selective to said dielectric barrier layer over said damascene conductor and said interlevel dielectric layer to said damascene conductor, extending said via opening through said dielectric barrier layer to said damascene conductor; and filling said via opening with an electrical conductor.