Etching a dielectric layer in an integrated circuit structure having a metal hard mask layer

摘要

The invention relates to the etching of a dielectric layer in an integrated circuit (IC) structure having a patterned metal hard mask layer. The method comprises feeding a gas mixture that includes a carbon monoxide (CO) and at least one fluorocarbon gas mixture into a reactor. The gas mixture has no oxygen (O₂) gas. The gas mixture is then converted into a plasma. The plasma selectively etches the dielectric layer. Typically, the dielectric layer comprises silicon.