Method and composition for polishing a substrate
Polishing compositions and methods for removing conductive materials and barrier materials from a substrate surface are provided. Polishing compositions are provided for removing at least a barrier material from a substrate surface by a chemical mechanical polishing process or by an electrochemical mechanical polishing process. The polishing compositions used in barrier removal may further be used after a process for electrochemical mechanical planarization process of a conductive material. The polishing compositions and methods described herein improve the effective removal rate of materials from the substrate surface with a reduction in planarization type defects.
1. A method of processing a substrate, comprising:
disposing a substrate having patterned feature definitions, a barrier material disposed in the patterned feature definitions, and a tungsten layer formed thereon in a polishing apparatus;
polishing the tungsten layer to expose the barrier layer;
polishing the barrier layer by a process comprising:
providing a barrier polishing composition comprising:
between about 1 wt. % and about 10 wt. % of an oxidizer;
between about 0.5 wt. % and about 5 wt. % of a chelating agent; between about 0.0001 wt % and about 1 wt % of a polymeric stabilizer;
between about 0.3 wt % and about 10 wt % of abrasive particles;
a pH between about 1 and about 6; and
a solvent; and
contacting the substrate to a polishing article;
providing relative motion between the substrate and the polishing article; and
removing the barrier material from the substrate, wherein the barrier layer is removed at a barrier layer removal rate to tungsten removal rate between about 30:1 and about 80:1.
2. The method of claim 1 , wherein the composition comprises:
the oxidizer comprises a peroxide compound
the chelating agent comprises a compound having one or more functional groups selected from the group consisting of carboxylic acid groups, amine groups, amide groups, and combinations thereof;
the polymeric stabilizer comprises a polyethylene derivative, a polyacrylic derivative, or a combination thereof;
the abrasive particles are selected from the group of alumina, silica, ceria, and combinations thereof; and
the solvent comprises water.
3. The method of claim 2 , wherein the composition comprises:
between about 1 wt. % and about 5 wt. % of hydrogen peroxide;
between about 0.5 wt. % and about 2 wt. % of a salt having one or more functional groups selected from the group consisting of carboxylic acid groups, amine groups, amide groups, and combinations thereof;
between about 0.01 wt % and about 1 wt % of a polyacrylic acid;
between about 0.3 wt % and about 5 wt % of alumina particles;
a pH between about 3 and about 6; and
water.
4. The method of claim 3 , wherein the composition comprises:
about 3 wt. % of hydrogen peroxide;
about 1 wt. % of ammonium citrate;
about 0.1 wt. % of polyacrylic acid;
about 4 wt % of alumina particles;
a pH between about 4 and about 5; and
a solvent.
5. A method of processing a substrate comprising:
disposing a substrate having patterned feature definitions, a barrier material disposed in the patterned feature definitions, and a tungsten layer formed thereon in a polishing apparatus having at least one electrochemical mechanical polishing station;
polishing the tungsten layer to expose the barrier layer, wherein polishing the tungsten layer comprises;
polishing the substrate in the at least one electrochemical mechanical polishing station to remove a first portion of the tungsten layer by a process comprising:
providing a first polishing composition between the first electrode and the substrate;
contacting the substrate to a polishing article at a first pressure between the substrate and the polishing article;
providing a first relative motion between the substrate and the polishing article; and
applying a first bias between the first electrode and the second electrode; and
polishing the substrate in the at least one electrochemical mechanical polishing station to remove a second portion of the tungsten layer by a process comprising:
providing a second polishing composition between the first electrode and the substrate;
contacting the substrate to a polishing article at a second pressure between the substrate and the polishing article;
providing a second relative motion between the substrate and the polishing article; and
applying a second bias between the first electrode and the second electrode;
polishing the barrier layer by a process comprising:
providing a barrier polishing composition comprising:
between about 1 wt. % and about 10 wt. % of an oxidizer;
between about 0.5 wt. % and about 5 wt. % of a chelating agent;
between about 0.0001 wt % and about 1 wt % of a polymeric stabilizer;
between about 0.3 wt % and about 10 wt % of abrasive particles;
a pH between about 1 and about 6; and
a solvent; and
contacting the substrate to a polishing article;
providing relative motion between the substrate and the polishing article; and
removing the barrier material from the substrate.
6. The method of claim 5 , wherein the barrier layer is removed at a barrier layer removal rate to tungsten removal rate between about 30:1 and about 80:1.
7. A method of processing a substrate comprising a dielectric surface, feature definitions formed in the dielectric surface, a barrier material disposed in the feature definitions and on the dielectric surface, and a conductive material disposed on the barrier material, the method comprising:
polishing the conductive material to expose the barrier material;
disposing the substrate in a process apparatus comprising a first electrode and a second electrode, wherein the substrate is in electrical contact with the second electrode;
providing a polishing composition between the first electrode and the substrate, wherein the polishing composition comprises:
an acid based electrolyte system;
one or more etching agents;
one or more etching inhibitors, wherein the one or more etching inhibitors are selected from the group consisting of polymethylacrylic acids, polycarboxylic acid, polyphosphate, and combinations thereof;
one or more activating agents;
one or more pH adjusting agents to provide a pH between about 2 and about 7; and
a solvent;
applying a pressure between the substrate and a polishing article by use of a polishing head;
providing relative motion between the substrate and the polishing article by mechanical means;
applying a bias between the first electrode and the second electrode; and
removing barrier material from the dielectric surface.
8. The method of claim 7 , wherein the bias is applied to the substrate to initiate an anodic dissolution at a current density between about 0.01 milliamps/cm 2 and about 20 milliamps/cm 2 .
9. The method of claim 7 , wherein the pressure applied between the substrate and polishing article is between about 0.01 and less than about 2 psi.
10. The method of claim 7 , wherein the one or more etching agents include a compound having one or more functional groups selected from the group consisting of amine groups, amide groups, carboxylate groups, dicarboxylate groups, tri-carboxylate groups, and combinations thereof.
11. A method of processing a substrate comprising a dielectric surface, feature definitions formed in the dielectric surface, a barrier material disposed in the feature definitions and the dielectric surface, and a conductive material disposed on the barrier material, the method comprising:
polishing the conductive material to expose the barrier material;
disposing the substrate in a process apparatus comprising a first electrode and a second electrode, wherein the substrate is in electrical contact with the second electrode;
providing a polishing composition between the first electrode and the substrate, wherein the polishing composition comprises;
an acid based electrolyte system;
one or more etching agents;
one or more etching inhibitors;
one or more activating agents, wherein the activating agents are selected from the group of iron compounds, aluminum compounds, hexafluorotitanium ([TiF 6 ] 2− ) salts, hexafluorosilicon ([SiF 6 ] 2− ), and combinations thereof;
one or more pH adjusting agents to provide a pH between about 2 and about 7; and
a solvent;
applying a pressure between the substrate and a polishing article by use of a polishing head;
providing relative motion between the substrate and the polishing article by mechanical means;
applying a bias between the first electrode and the second electrode; and
removing barrier material from the dielectric surface.
12. The method of claim 7 , wherein the conductive material is tungsten, and the barrier material is selected from the group consisting of titanium, titanium nitride, tantalum, tantalum nitride, and ruthenium.
13. The method of claim 7 , wherein the substrate in electrical contact with the second electrode comprises contacting the substrate with a conductive polishing article and the conductive polishing article is electrically connected with the second electrode.
14. The method of claim 13 , wherein the polishing article is a conductive polishing material.