Method of forming a bond pad
View Patent ↗A front-end method of fabricating nickel plated caps over copper bond pads used in a memory device. The method provides protection of the bond pads from an oxidizing atmosphere without exposing sensitive structures in the memory device to the copper during fabrication.
1. A method of forming a bond pad comprising:
forming integrated circuitry on a substrate;
forming at least one dielectric layer over said integrated circuitry;
removing at least part of said dielectric layer;
forming said bond pad in an area where said dielectric layer was removed;
forming an oxide layer over said at least one dielectric layer and said bond pad;
removing the oxide layer in an area over the bond pad;
plating the bond pad with nickel; and
after plating the bond pad with nickel, removing a remainder of said oxide layer.
2. The method of claim 1 , wherein the step of plating the bond pad with nickel comprises exposing the bond pad to an electroless nickel bath.
3. The method of claim 2 , wherein the nickel is plated to a thickness of about 4000 Angstroms.
4. The method of claim 1 , wherein the step of forming said bond pad comprises depositing a copper material.
5. The method of claim 1 , wherein said step of removing the oxide layer in an area over the bond pad comprises:
forming a photoresist over said oxide layer, said photoresist having a bond pad pattern located over said bond pad.
6. The method of claim 1 , further comprising, after said step of removing said oxide layer, depositing a cell material over said integrated circuitry.
7. The method of claim 6 , wherein said step of depositing a cell material comprises forming a layer of cell material.
8. The method of claim 6 , wherein said cell material comprises resistance variable cell material.
9. The method of claim 6 , wherein said cell material includes at least one of the following materials:
germanium selenide;
chalcogenide glass; and
silver-containing material.
10. A method of forming a device having a bond pad, said method comprising:
forming a bond pad in an area of a dielectric material;
forming an oxide layer over said dielectric layer and said bond pad;
removing the oxide layer in an area over the bond pad;
plating the bond pad with nickel; and
after said step of plating the bond pad with nickel, depositing a cell material over said dielectric layer.
11. The method of claim 10 , wherein said step of forming a bond pad comprises depositing a copper material in said area of said dielectric material.
12. The method of claim 10 , wherein said bond pad is formed in a peripheral area of said device.
13. The method of claim 10 , wherein said step of plating the bond pad with nickel further comprises exposing the bond pad to an electroless nickel bath.
14. A method of forming a device having a bond pad, said method comprising:
forming a bond pad in an area of a dielectric material;
forming an oxide layer over said dielectric layer and said bond pad;
removing the oxide layer in an area over the bond pad;
plating the bond pad with nickel; and
after said step of plating the bond pad with nickel, removing a remainder of said oxide layer.
15. The method of claim 14 , further comprising, after said step of removing said oxide layer, depositing a cell material over integrated circuitry of said device.
16. The method of claim 15 , wherein said device is formed such that said cell material is not substantially exposed to copper during fabrication of said device.
17. The method of claim 15 , wherein said device is formed such that said bond pad is not substantially exposed to oxygen during fabrication of said device.