IPC분류정보
| 국가/구분 |
United States(US) Patent
등록
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| 국제특허분류(IPC7판) |
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| 출원번호 |
US-0653548
(2003-09-02)
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발명자
/ 주소 |
- Bojkov, Christo P.
- Arbuthnot, Diane L.
- Kunesh, Robert F.
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| 출원인 / 주소 |
- Texas Instruments Incorporated
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| 인용정보 |
피인용 횟수 :
31 인용 특허 :
0 |
초록
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A method for preparing a bonding pad on an integrated circuit wafer by the steps of depositing a conductive seed layer (104) on the bonding pad; depositing a metal layer (301, 302, and 303) over a portion of the conductive seed layer; and immersing the wafer in an etchant solution (501) to remove th
A method for preparing a bonding pad on an integrated circuit wafer by the steps of depositing a conductive seed layer (104) on the bonding pad; depositing a metal layer (301, 302, and 303) over a portion of the conductive seed layer; and immersing the wafer in an etchant solution (501) to remove the portion of the seed layer not covered by the metal layer. The etchant solution contains a chelating agent that bonds ions from the seed layer. When the seed layer is copper or a refractory metal, and the metal layer is gold or palladium, the preferred chelating agent is selected from, but is not limited to, but is not limited to, the families of ethylenediaminetetraacetic acids (EDTA), 8-hydroxy-quinolines, including 8-hydroxy-quinoline-5-sulfonic acid, porphyrins, and phthalocyanines.
대표청구항
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1. A method for the removal of a first metal from the presence of a second noble metal, comprising the step of:providing a layer of the first metal;providing a layer of the second noble metal having a top surface, partially covering the layer of the first metal;exposing the uncovered first metal lay
1. A method for the removal of a first metal from the presence of a second noble metal, comprising the step of:providing a layer of the first metal;providing a layer of the second noble metal having a top surface, partially covering the layer of the first metal;exposing the uncovered first metal layer and the top surface of the second metals in an oxidizing etchant solution containing sulfuric acid and hydrogen peroxide and a chelating agent, said chelating agent selectively forming a complex with the first metal.2. The method according to claim 1 wherein said first metal is copper.3. The method according to claim 1, wherein said second noble metal is gold.4. The method according to claim 1 wherein said second noble metal is palladium.5. The method according to claim 1 wherein said chelating agent is selected from a group consisting of the families of ethylenediaminetetraacetic acids (EDTA), 8-hydroxyquinolines, including 8-hydroxy-quinoline-5-sulfonic acid (HQS), porphyrins, and phthalocyanines.6. A method for making a wire-bond, comprising the steps of:depositing a conductive seed layer on a bonding pad on a wafer;depositing a noble metal layer covering a portion of said conductive seed layer;immersing said wafer in an etchant solution containing sulfuric acid and hydrogen peroxide, exposing the surface of the noble metal layer and the uncovered portion of the seed layer to remove the portion of said seed layer not covered by said metal layer, said etchant solution containing a chelating agent that bonds ions from said seed layer; andwire-bonding a wire to the exposed surface of the noble metal layer at the bonding pad.7. The method according to claim 6 wherein said conductive seed layer is copper.8. The method according to claim 6 wherein said conductive seed layer is a refractory metal including titanium, tungsten, tantalum, nickel, vanadium, or an alloy thereof.9. The method according to claim 6 wherein said noble metal layer is gold.10. The method according to claim 6 wherein said noble metal layer is palladium.11. The method according to claim 6 wherein said chelating agent is selected from a group consisting of the families of ethylenediaminetetraacetic acids (EDTA), 8-hydroxyquinolines, including 8-hydroxy-quinoline-5-sulfonic acid (HQS), porphyrins, and phthalocyanines.12. A method for preparing a bonding pad on an integrated circuit wafer, comprising the steps of:depositing a conductive seed layer containing copper on said bonding pad;depositing a metal layer covering a portion of said conductive seed layer, said metal layer comprising a metal more noble than copper; andimmersing said wafer in an etchant solution containing sulfuric acid and hydrogen peroxide, exposing the uncovered portion of the seed layer to remove the portion of said seed layer not covered by said noble metal layer, said etchant solution containing a chelating agent that binds copper ions from said seed layer, whereby redeposition of said copper ions on said metal layer is avoided.13. The method according to claim 12, wherein said conductive seed layer is copper.14. The method according to claim 12 wherein said conductive seed layer is a refractory metal including titanium, tungsten, tantalum, nickel, vanadium, or an alloy thereof.15. The method according to claim 12, wherein said noble metal layer is made of gold.16. The method according to claim 12, wherein said noble metal layer is made of palladium.17. The method according to claim 12, wherein said chelating agent is selected from a group consisting of the families of ethylenediaminetetraacetic acids (EDTA), 8-hydroxyquinolines, including 8-hydroxy-quinoline-5-sulfonic acid (HQS), porphyrins, and phthalocyanines.
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