IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0773316
(2007-07-03)
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등록번호 |
US-7658790
(2010-04-02)
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발명자
/ 주소 |
- Gorer, Alexander
- Chiang, Tony
- Lang, Chi-I
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출원인 / 주소 |
|
인용정보 |
피인용 횟수 :
1 인용 특허 :
6 |
초록
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An electroless solution for deposition of a cobalt-based alloy on a substrate is provided. The electroless solution may be formed by mixing first and second solutions, with the first and second solutions being prepared from concentrated precursors. In one embodiment, the first solution contains a co
An electroless solution for deposition of a cobalt-based alloy on a substrate is provided. The electroless solution may be formed by mixing first and second solutions, with the first and second solutions being prepared from concentrated precursors. In one embodiment, the first solution contains a cobalt (Co) ion source and a complexing and deposition selectivity agent. In one embodiment, the cobalt concentration in the first solution is at least 90 millimoles per liter. The second solution contains a reducing agent. In one embodiment, the reducing agent is dimethylamineborane (DMAB) having a concentration of at least 10 grams per liter. In other embodiments, the first solution also contains a tungsten (W) ion source, and either the first or second solution also contains a phosphorous (P) ion source.
대표청구항
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What is claimed is: 1. A method for forming an electroless solution for depositing a cobalt-based alloy on a substrate, comprising: forming a first solution comprised of a cobalt (Co) ion source and a complexing and deposition selectivity agent, the first solution having a cobalt (Co) concentration
What is claimed is: 1. A method for forming an electroless solution for depositing a cobalt-based alloy on a substrate, comprising: forming a first solution comprised of a cobalt (Co) ion source and a complexing and deposition selectivity agent, the first solution having a cobalt (Co) concentration of at least 90 millimoles per liter and heating the first solution to a temperature in the approximate range of 40° C. to 100° C.; forming an unheated second solution comprised of a reducing agent; mixing the heated first solution and the unheated second solution to form the electroless solution, wherein the volume ratio of the first solution to the second solution is in the approximate range of 1:2 to 10:1; and heating the electroless solution to a temperature of approximately 80° C. immediately before application of the electroless solution to the substrate. 2. The method of forming the electroless solution of claim 1, wherein forming the second solution includes selecting the reducing agent from the group consisting of boric acid, a borohydride, and alkyl borane compounds. 3. The method of forming the electroless solution of claim 2, wherein the borohydride is tetramethylammonium borohydride. 4. The method of forming the electroless solution of claim 2, wherein the alkyl borane compound is dimethylamineborane (DMAB). 5. The method of forming the electroless solution of claim 1, wherein the cobalt (Co) ion source is selected from the group consisting of cobalt acetate, cobalt chloride, cobalt hydroxide, cobalt nitrate, cobalt sulfate, and cobalt sulfate heptahydrate. 6. The method of forming the electroless solution of claim 1, wherein the complexing and deposition selectivity agent is selected from the group consisting of citric acid, ammonium chloride, ammonium citrate, 3 NH4-citrate, acetic acid, ethylenediamine, tetramethylammonium hydroxide (TMAH), and combinations thereof. 7. The method of forming the electroless solution of claim 6, wherein an amount of the complexing and deposition selectivity agent is such that a molar ratio of citric acid to cobalt (Co) in the electroless solution is in a range from 1.5 to 4.5. 8. The method of forming the electroless solution of claim 1, wherein either the first solution or the second solution further comprises a phosphorous (P) ion source. 9. The method of forming the electroless solution of claim 8, wherein the phosphorous (P) ion source is hypophosphorous acid, and an amount of hypophosphorous acid is such that a molar ratio of hypophosphorous acid to cobalt (Co) in the first solution is in a range from 1:1 to 3:1. 10. The method of forming the electroless solution of claim 1, wherein the first solution further comprises a tungsten (W) ion source. 11. The method of forming the electroless solution of claim 10, wherein the tungsten (W) ion source is selected from the group consisting of phosphotungstic acid, tungstic acid, and ammonium tungstate. 12. The method of forming the electroless solution of claim 11, wherein the tungsten (W) ion source is phosphotungstic acid, and an amount of phosphotungstic acid is such that a molar ratio of phosphotungstic acid to cobalt (Co) in the first solution is in a range from 1.25:1 to 5:1. 13. The method of forming the electroless solution of claim 1, wherein the first solution has a pH in a range from 8.9 to 10. 14. The method of forming the electroless solution of claim 1, wherein the first solution is mixed with the second solution so that the volume ratio of the first solution to the second solution is in the approximate range of 1:1 to 10:1. 15. A method for electrolessly depositing a cobalt based alloy on a substrate, comprising: forming an electroless solution by mixing a first concentrated solution consisting essentially of cobalt sulfate, citric acid, TMAH, ammonium chloride, phosphotungstic acid, and hypophosphorous acid at a temperature of approximately 80° C. with a second concentrated solution consisting essentially of dimethylborane (DMAB) having a temperature of approximately 20° C.; and applying the electroless solution to a patterned surface of the substrate, the patterned surface of the substrate having copper interconnection separated by a silicon carbonitride-based dielectric; and depositing the cobalt based alloy comprising cobalt, tungsten, phosphorous, and boron. 16. The method of claim 15, wherein the ratio of the first solution to the second solution is 1:1. 17. The method of claim 15, wherein the pH of the electroless solution is approximately 9.5. 18. The method of claim 16, wherein the cobalt based alloy selectively deposits on copper surfaces wherein the temperature of the electroless solution when it is applied to the substrate is approximately 80° C.
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