CMP of copper/ruthenium/tantalum substrates
The invention provides a chemical-mechanical polishing composition for polishing a substrate. The polishing composition comprises an abrasive, an oxidizing agent, an amphiphilic nonionic surfactant, calcium ion or magnesium ion, a corrosion inhibitor for copper, and water, wherein the pH of the polishing composition is about 6 to about 12. The invention further provides a method of chemically-mechanically polishing a substrate with the aforementioned polishing composition.
1 . A chemical-mechanical polishing composition comprising:
(a) about 0.01 wt. % to about 10 wt. % of an abrasive,
(b) about 0.01 wt. % to about 10 wt. % of an oxidizing agent,
(c) about 1 ppm to about 5000 ppm of an amphiphilic nonionic surfactant comprising a head group and a tail group,
(d) about 1 ppm to about 500 ppm of calcium ion or magnesium ion,
(e) about 0.001 wt. % to about 0.5 wt. % of a corrosion inhibitor for copper, and
(f) water,
wherein the pH of the polishing composition is about 6 to about 12.
2 . The polishing composition of claim 1 , wherein the abrasive comprises α-alumina.
3 . The polishing composition of claim 2 , wherein the α-alumina is treated with a negatively-charged polymer or copolymer selected from the group consisting of poly(2-acrylamido-2-methylpropane sulfonic acid) and polystyrenesulfonic acid.
4 . The polishing composition of claim 2 , wherein the polishing composition further comprises silica.
5 . The polishing composition of claim 1 , wherein the oxidizing agent is hydrogen peroxide, and wherein the polishing composition comprises about 0.1 wt. % to about 5 wt. % of hydrogen peroxide.
6 . The polishing composition of claim 1 , wherein the polishing composition further comprises an organic acid selected from the group consisting of malonic acid, succinic acid, adipic acid, lactic acid, malic acid, citric acid, glycine, aspartic acid, gluconic acid, iminodiacetic acid, fumaric acid, and combinations thereof.
7 . The polishing composition of claim 1 , wherein the polishing composition further comprises tartaric acid.
8 . The polishing composition of claim 1 , wherein the amphiphilic nonionic surfactant is a block or graft copolymer comprising polyoxyethylene and polyethylene.
9 . The polishing composition of claim 8 , wherein the amphiphilic nonionic surfactant has a HLB of about 8 or more.
10 . The polishing composition of claim 8 , wherein the amphiphilic nonionic surfactant has a molecular weight of about 5,000 Daltons or more.
11 . The polishing composition of claim 1 , wherein the corrosion inhibitor for copper is at least one heterocyclic compound selected from the group consisting of benzotriazole, 4-methylbenzotriazole, 5-methylbenzotriazole, 5-chlorobenzotriazole, and combinations thereof.
12 . The polishing composition of claim 11 , wherein the corrosion inhibitor for copper is benzotriazole, and wherein the polishing composition comprises about 0.005 wt. % to about 0.1 wt. % of benzotriazole.
13 . The polishing composition of claim 1 , wherein the polishing composition comprises about 5 ppm to about 250 ppm of calcium ion.
14 . The polishing composition of claim 1 , wherein the polishing composition further comprises ammonium hydroxide.
15 . A method of chemically-mechanically polishing a substrate, which method comprises:
(i) providing a substrate,
(ii) providing a chemical-mechanical polishing composition comprising:
(a) about 0.01 wt. % to about 10 wt. % of an abrasive,
(b) about 0.01 wt. % to about 10 wt. % of an oxidizing agent,
(c) about 1 ppm to about 5000 ppm of an amphiphilic nonionic surfactant comprising a head group and a tail group,
(d) about 1 ppm to about 500 ppm of calcium ion or magnesium ion,
(e) about 0.001 wt. % to about 0.5 wt. % of a corrosion inhibitor for copper, and
(f) water,
wherein the pH of the polishing composition is about 6 to about 12,
(iii) contacting the substrate with a polishing pad with the polishing composition therebetween,
(iv) moving the polishing pad and polishing composition relative to the substrate, and
(iv) abrading at least a portion of the substrate to polish the substrate.
16 . The method of claim 15 , wherein the substrate comprises at least one layer of copper, at least one layer of ruthenium, and at least one layer of tantalum, and wherein at least one ruthenium layer is disposed between at least one copper layer and at least one tantalum layer.
17 . The method of claim 16 , wherein the abrasive comprises α-alumina.
18 . The method of claim 17 , wherein the α-alumina is treated with a negatively-charged polymer or copolymer selected from the group consisting of poly(2-acrylamido-2-methylpropane sulfonic acid) and polystyrenesulfonic acid.
19 . The method of claim 17 , wherein the abrasive further comprises silica.
20 . The method of claim 16 , wherein the oxidizing agent is hydrogen peroxide, and wherein the polishing composition comprises about 0.1 wt. % to about 5 wt. % of hydrogen peroxide.
21 . The method of claim 16 , wherein the polishing composition further comprises an organic acid selected from the group consisting of malonic acid, succinic acid, adipic acid, lactic acid, malic acid, citric acid, glycine, aspartic acid, gluconic acid, iminodiacetic acid, fumaric acid, and combinations thereof.
22 . The method of claim 16 , wherein the polishing composition further comprises tartaric acid.
23 . The method of claim 16 , wherein the amphiphilic nonionic surfactant is a block or graft copolymer comprising polyoxyethylene and polyethylene.
24 . The method of claim 23 , wherein the amphiphilic nonionic surfactant has a HLB of about 8 or more.
25 . The method of claim 23 , wherein the amphiphilic nonionic surfactant has a molecular weight of about 5,000 Daltons or more.
26 . The method of claim 16 , wherein the corrosion inhibitor for copper is at least one heterocyclic compound selected from the group consisting of benzotriazole, 4-methylbenzotriazole, 5-methylbenzotriazole, 5-chlorobenzotriazole, and combinations thereof.
27 . The method of claim 26 , wherein the corrosion inhibitor for copper is benzotriazole, and wherein the polishing composition comprises about 0.005 wt. % to about 0.1 wt. % of benzotriazole.
28 . The method of claim 16 , wherein the polishing composition comprises about 5 ppm to about 250 ppm of calcium ion.
29 . The method of claim 16 , wherein the polishing composition further comprises ammonium hydroxide.
30 . The method of claim 16 , wherein the pH of the polishing composition is about 7 to about 9.
31 . The method of claim 16 , wherein at least one layer of ruthenium and at least one layer of copper are in electrical contact, and wherein the difference between the open circuit potential of copper and the open circuit potential of ruthenium in the polishing composition is about 50 mV or less.
32 . The method of claim 16 , wherein at least a portion of at least one tantalum layer is abraded to polish the substrate.