SELF-ALIGNED BACK END OF LINE CUT

摘要

Embodiments of the present invention provide a method for self-aligned metal cuts in a back end of line structure. Sacrificial Mx+1 lines are formed above metal Mx lines. Spacers are formed on each Mx+1 sacrificial line. The gap between the spacers is used to determine the location and thickness of cuts to the Mx metal lines. This ensures that the Mx metal line cuts do not encroach on vias that interconnect the Mx and Mx+1 levels. It also allows for reduced limits in terms of via enclosure rules, which enables increased circuit density.

主权项

1. A method of forming a semiconductor structure, comprising:
forming a plurality of Mx metal lines in a dielectric layer; depositing a capping layer over the plurality of Mx metal lines; forming a plurality of sacrificial Mx+1 lines on the dielectric layer; forming spacers adjacent to each of the plurality of sacrificial Mx+1 lines; depositing a first resist layer over the plurality of sacrificial Mx+1 lines; forming an opening in the first resist layer at a location corresponding to a line cut for at least one Mx metal line of the plurality of Mx metal lines; removing the capping layer at the location corresponding to the line cut; and performing a metal etch to cut the at least one Mx metal line of the plurality of Mx metal lines.