Metal air gap

摘要

Methods are described for forming “air gaps” between adjacent copper lines on patterned substrates. The air gaps may be located between copper lines on the same layer. A sacrificial patterned dielectric layer is used as a template to form a layer of copper by physical vapor deposition in a substrate processing system (i.e. a mainframe). Without breaking vacuum, the copper is redistributed into the gaps with a copper reflow process. Dielectric material from the template is removed, again in the same mainframe, using a remote fluorine etch process leaving the gapfill copper as the structural material. A conformal capping layer (such as silicon carbon nitride) is then deposited (e.g. by ALD) to seal the patterned substrate before removing the patterned substrate from the mainframe.

主权项

1. A method of forming an integrated circuit, the method comprising:
transferring a patterned substrate into a substrate processing mainframe, wherein the patterned substrate comprises a patterned dielectric layer with two adjacent lines of silicon oxide; forming a conformal titanium barrier layer over the two adjacent lines of silicon oxide; and forming a nonconformal layer of copper by physical vapor deposition onto the conformal titanium barrier layer; and reflowing the nonconformal layer of copper to form a copper gapfill line between the two adjacent lines of silicon oxide and exposing the conformal titanium barrier layer at the tops of the two adjacent lines of silicon oxide; and etching the conformal titanium barrier layer from the tops of the two adjacent lines of silicon oxide; etching the two adjacent lines of silicon oxide forming voids on either side of the copper gapfill line by introducing radical-fluorine from a remote plasma region into a substrate processing region housing the substrate; and depositing a conformal capping layer over the patterned substrate to protect the copper gapfill line from oxidation; and removing the patterned substrate from the substrate processing mainframe, wherein the patterned substrate is not exposed to atmosphere between transferring the patterned substrate into the substrate processing mainframe and removing the patterned substrate from the substrate processing mainframe.