Method for forming tungsten film having low resistivity, low roughness and high reflectivity

摘要

Top-down methods of increasing reflectivity of tungsten films to form films having high reflectivity, low resistivity and low roughness are provided. The methods involve bulk deposition of tungsten followed by a removing a top portion of the deposited tungsten. In particular embodiments, removing a top portion of the deposited tungsten involve exposing it to a fluorine-containing plasma. The methods produce low resistivity tungsten bulk layers having lower roughness and higher reflectivity. The smooth and highly reflective tungsten layers are easier to photopattern than conventional low resistivity tungsten films. Applications include forming tungsten bit lines.

主权项

1. A method of forming a tungsten layer on a substrate surface, the method comprising:
receiving a substrate having an exposed deposited tungsten layer on a planar surface of the substrate, wherein the deposited tungsten layer has a thickness T1; and removing a top portion of the deposited tungsten layer to form a tungsten bulk layer having thickness Td on the planar surface, wherein Td is less than T1, wherein the top portion is between about 5% and 25% of the thickness T1 of the deposited tungsten layer; and halting the removing once the top portion is removed and the tungsten bulk layer has a thickness of Td, and further comprising introducing a fluorine-containing compound to a remote plasma generator upstream of a chamber that houses the substrate, generating atomic fluorine within the remote plasma generator, and flowing atomic fluorine from the remote plasma generator to the chamber to remove the top portion of the deposited tungsten layer.