Cobalt and nickel electroless plating in microelectronic devices
View Patent ↗An electroless plating method and composition for depositing Co, Ni, or alloys thereof onto a metal-based substrate in manufacture of microelectronic devices, involving a source of deposition ions selected from the group consisting of Co ions and Ni ions, a reducing agent for reducing the depositions ions to metal onto the substrate, and a hydrazine-based leveling agent.
1. A method for electrolessly depositing a cobalt-based alloy selectively onto a metal-based substrate in manufacture of microelectronic devices, the method comprising:
contacting the metal-based substrate with an electroless deposition composition to thereby electrolessly deposit the cobalt-based alloy selectively onto the metal-based substrate, wherein:
the electroless deposition composition has a pH between about 7.5 and about 10;
the electroless deposition composition comprises a) a source of cobalt deposition ions b) a source of hypophosphite for use as a reducing agent for reducing the depositions ions to metal onto the substrate, c) a hydrazine-based leveling agent present at a concentration to yield a hydrazine concentration in the electroless deposition composition from about 1 ppm to about 100 ppm; and d) a source of tungsten ions; and
the cobalt-based alloy comprises cobalt metal, elemental phosphorus, and tungsten metal.
2. The method of claim 1 wherein the electroless deposition composition has a pH from about 8.7 to about 9.3.
3. The method of claim 1 wherein the hydrazine-based leveling agent is selected from the group consisting of hydrazine and derivatives of hydrazine, and wherein the hydrazine and derivatives of hydrazine introduce free hydrazine upon dissolution into the electroless deposition composition.
4. The method of claim 1 wherein the hydrazine-based leveling agent is selected from the group consisting of hydrazine hydrate, hydrazine sulfate, hydrazine chloride, hydrazine bromide, hydrazine dihydrochloride, hydrazine dihydrobromide, and hydrazine tartrate.
5. The method of claim 1 wherein the hydrazine-based leveling agent is a derivative of hydrazine wherein the derivative of hydrazine forms hydrazine as a reaction product in the electroless deposition composition.
6. The method of claim 1 wherein the hydrazine-based leveling agent is selected from the group consisting of 2-hydrazinopyridine, hydrazobenzene, phenyl hydrazine, hydrazine N,N diacetic acid, 1,2-diethylhydrazine, monomethylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, 4-hydrazinobenzenesulfonic acid, hydrazinecarboxylic acid, 2-hydrazinoethanol, semicarbazide, carbohydrazide, aminoguanidine hydrochloride, 1,3-diaminoguanidine monohydrochloride, and triaminoguanidine hydrochloride.
7. The method of claim 1 wherein the hydrazine-based leveling agent is present at a concentration to yield a hydrazine concentration in the electroless deposition composition from about 10 ppm to about 20 ppm.
8. A method for electrolessly depositing a cobalt-based alloy selectively onto a metal interconnect feature located in a SiO 2 or low k dielectric substrate, the method comprising:
contacting the substrate with an electroless deposition composition to thereby electrolessly deposit the cobalt-based alloy selectively onto the metal interconnect feature, wherein:
the electroless deposition composition comprises a) a source of cobalt deposition ions b) a source of hypophosphite for use as a reducing agent for reducing the depositions ions to metal onto the substrate, c) a hydrazine-based leveling agent present in a concentration to yield a hydrazine concentration in the electroless deposition composition from about 1 ppm to about 100 ppm; and d) a source of tungsten ions; and
the cobalt-based alloy comprises cobalt metal, elemental phosphorus, and tungsten metal.
9. The method of claim 8 wherein the electroless deposition composition has a pH from about 7.5 to about 10.0.
10. The method of claim 8 wherein the metal interconnect feature is a copper interconnect feature.
11. The method of claim 8 wherein the substrate is contacted with the electroless deposition composition by immersing the substrate into the electroless deposition composition.
12. The method of claim 8 wherein the electroless deposition composition has a pH from about 8.7 to about 9.3.
13. The method of claim 8 wherein the hydrazine-based leveling agent is selected from the group consisting of hydrazine and derivatives of hydrazine, and wherein the hydrazine and derivatives of hydrazine introduce free hydrazine upon dissolution into the electroless deposition composition.
14. The method of claim 8 wherein the hydrazine-based leveling agent is selected from the group consisting of hydrazine hydrate, hydrazine sulfate, hydrazine chloride, hydrazine bromide, hydrazine dihydrochloride, hydrazine dihydrobromide, and hydrazine tartrate.
15. The method of claim 8 wherein the hydrazine-based leveling agent is a derivative of hydrazine wherein the derivative of hydrazine forms hydrazine as a reaction product in the electroless deposition composition.
16. The method of claim 8 wherein the hydrazine-based leveling agent is selected from the group consisting of 2-hydrazinopyridine, hydrazobenzene, phenyl hydrazine, hydrazine N,N diacetic acid, 1,2-diethylhydrazine, monomethylhydrazine, 1,1-dimethylhydrazine, 1,2-dimethylhydrazine, 4-hydrazinobenzenesulfonic acid, hydrazinecarboxylic acid, 2-hydrazinoethanol, semicarbazide, carbohydrazide, aminoguanidine hydrochloride, 1,3-diaminoguanidine monohydrochloride, and triaminoguanidine hydrochloride.
17. The method of claim 8 wherein the hydrazine-based leveling agent is present at a concentration to yield a hydrazine concentration in the electroless deposition composition from about 10 ppm to about 20 ppm.