DIAGONAL HARDMASKS FOR IMPROVED OVERLAY IN FABRICATING BACK END OF LINE (BEOL) INTERCONNECTS

摘要

Self-aligned via and plug patterning using diagonal hardmasks for improved overlay in fabricating back end of line (BEOL) interconnects is described. In an example, a method of fabricating an interconnect structure for an integrated circuit involves forming a first hardmask layer above an interlayer dielectric layer disposed above a substrate. The first hardmask layer includes a plurality of first hardmask lines having a first grating in a first direction and comprising one or more sacrificial materials interleaved with the first grating. The method also involves forming a second hardmask layer above the first hardmask layer. The second hardmask layer includes a plurality of second hardmask lines having a second grating in a second direction, diagonal to the first direction. The method also involves, using the second hardmask layer as a mask, etching the first hardmask layer to form a patterned first hardmask layer. The etching involves removing a portion of the one or more sacrificial materials.

主权项

1. An interconnect structure for an integrated circuit, the interconnect structure comprising:
an interlayer dielectric layer disposed above a substrate; and a grating structure disposed above the interlayer dielectric layer and comprising co-planar alternating dielectric hardmask lines and conductive lines, wherein one or more of the conductive lines extends into the interlayer dielectric layer, and one or more of the conductive lines does not extend into the interlayer dielectric layer.