Electrodeposition of cobalt tungsten films
AssigneeLam Research Corporation
InventorsTighe A. Spurlin, Edward C. Opocensky, Zhange Feng, Matthew A. Rigsby, Jonathan David Reid
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Abstract
Tungsten-containing metal films may be deposited in recessed features of semiconductor substrates by electrodeposition. The tungsten-containing metal film is electrodeposited under conditions so that the tunsten-containing metal film is free or substantially free of oxide. Conditions are optimized during electrodeposition for pH, tungsten concentration, and current density, among other parameters. The tungsten-containing metal film may include cobalt tungsten alloy, cobalt nickel tungsten alloy, or nickel tungsten alloy, where a tungsten content in the tungsten-containing metal film is between about 1-20 atomic %.
Claims20
A method of electroplating a tungsten-containing metal film on a semiconductor substrate, the method comprising:
- providing a semiconductor substrate to an electroplating apparatus, wherein the semiconductor substrate has at least one recessed feature and comprises an exposed conductive seed layer at least on sidewalls of the at least one recessed feature;
- contacting the semiconductor substrate with an electroplating solution in the electroplating apparatus;
- and
- cathodically biasing the semiconductor substrate in the electroplating apparatus to electroplate a tungsten-containing metal film and electrochemically fill the at least one recessed feature with the tungsten-containing metal film, wherein the tungsten-containing metal film comprises a metal selected from a group consisting of cobalt, nickel, and combinations thereof, wherein a tungsten content in the tungsten-containing metal film is between about 1-20 atomic %.
An aqueous electroplating solution for electroplating a tungsten-containing metal film, wherein the aqueous electroplating solution comprises:
- a source of tungsten, wherein the source of tungsten comprises tungsten-oxygen bonds, and wherein concentration of tungsten in the aqueous electroplating solution is equal to or less than about 4 g/L;
- a source of a metal in addition to the source of tungsten, wherein the metal is selected from a group consisting of cobalt, nickel, and combinations thereof;
- and
- an acid, wherein the aqueous electroplating solution has a pH of less than about 6.
An apparatus for electroplating tungsten-containing metal film on a semiconductor substrate, the apparatus comprising:
- an electroplating chamber configured to hold an electroplating solution;
- a substrate holder configured to hold the semiconductor substrate in the electroplating solution;
- a power supply;
- and
- a controller configured with program instructions for performing the following operations:
- contacting a semiconductor substrate with an electroplating solution, wherein the semiconductor substrate has a plurality of recessed features, and wherein the electroplating solution comprises a source of tungsten and a source of a metal selected from a group consisting of cobalt, nickel, and combinations thereof;
- and
- cathodically biasing the semiconductor substrate to electroplate the tungsten-containing metal film and electrochemically fill the plurality of recessed features with the tungsten-containing metal film, wherein a tungsten content in the tungsten-containing metal film is between about 1-20 atomic %.
Dependencies are inferred from the claim text.