AIR-GAP SCHEME FOR BEOL PROCESS

摘要

The present disclosure relates a back-end-of-the-line (BEOL) metallization stack having an air gap disposed between adjacent metal interconnect features, which provides for an inter-level dielectric material with a low dielectric constant. In some embodiments, the BEOL metallization stack has an inter-level dielectric (ILD) layer disposed over a substrate. A metal interconnect layer is disposed within the ILD layer, and an air gap is arranged disposed within the ILD layer at a position between a first feature and a second feature of the metal interconnect layer. The air gap has an upper surface with a first curve that meets a second curve at a peak arranged below a top of the metal interconnect layer. The first curve becomes steeper as a distance from the peak decreases and the second curve becomes steeper as a distance from the peak decreases.

主权项

1. A back-end-of-the-line (BEOL) metal interconnect stack, comprising:
an inter-level dielectric (ILD) layer disposed over a substrate; a metal interconnect layer disposed within the ILD layer; and an air gap disposed within the ILD layer at a position between a first feature and a second feature of the metal interconnect layer, wherein the air gap comprises an upper surface having a first curve that meets a second curve at a peak arranged below a top of the metal interconnect layer, wherein the first curve becomes steeper as a distance from the peak decreases and wherein the second curve becomes steeper as a distance from the peak decreases.