Interconnect structure and forming method thereof

摘要

An interconnect structure and a forming method thereof are provided. The method includes: providing a semiconductor substrate which has semiconductor devices formed therein; forming a conductive layer on the semiconductor substrate; forming a mask layer on the conductive layer; forming a groove in the mask layer and the conductive layer, the groove having a depth-to-width ratio greater than 0.8; and depositing an intermetallic dielectric layer to cover the mask layer and fill the groove, wherein an air gap is formed in a portion of the intermetallic dielectric layer in the groove. The mask layer is formed on the conductive layer, so that the depth-to-width ratio of the groove between adjacent interconnects is increased. Besides, the air gap with a relatively large size is formed between two adjacent interconnects. Therefore, a dielectric constant and parasitic capacitance between adjacent interconnects are reduced evidently, and the performance of the semiconductor devices is improved.

主权项

1. A method for forming an interconnect structure, comprising:
providing a semiconductor substrate that has semiconductor devices formed therein; forming a conductive layer on the semiconductor substrate; forming a mask layer on the conductive layer; forming a groove in the mask layer and the conductive layer, the groove having a depth-to-width ratio greater than 0.8, wherein a depth of the groove is a sum of a depth of the mask layer and a depth of the conductive layer; and depositing an intermetallic dielectric layer to cover the mask layer and fill the groove, wherein an air gap is formed in a portion of the intermetallic dielectric layer in the groove.