Reliable metal bumps on top of I/O pads after removal of test probe marks
View Patent ↗In accordance with the objectives of the invention a new method is provided for the creation of metal bumps over surfaces of I/O pads. Contact pads are provided over the surface of a layer of dielectric. The aluminum of the I/O pads, which have been used as I/O pads during wafer level semiconductor device testing, is completely or partially removed over a surface area that is smaller than the surface area of the contact pad using methods of metal dry etching or wet etching. The contact pad can be accessed either by interconnect metal created in a plane of the contact pad or by via that are provided through the layer of dielectric over which the contact pad has been deposited. The process can be further extended by the deposition, patterning and etching of a layer of polyimide over the layer of passivation that serves to protect the contact pad.
1. A circuit component comprising:
a semiconductor substrate;
a dielectric layer directly on said semiconductor substrate, wherein a via is in said dielectric layer and penetrates through said dielectric layer;
a conductive pad directly on said dielectric layer, said conductive pad coupled to said semiconductor substrate through said via;
a passivation layer on said dielectric layer and directly on a surface of said conductive pad opposite said dielectric layer, wherein a first opening in said passivation layer exposes a contact point of said conductive pad, in which a thickness of the conductive pad covered by the passivation layer is greater than a thickness of the conductive pad exposed by the first opening in the passivation layer;
a polymer layer on said passivation layer and said contact point and in said first opening, wherein a second opening in said polymer layer exposes said contact point; and
a conductive interconnect on said contact point and said polymer layer, wherein said conductive interconnect is coupled to said contact point through said second opening, wherein said conductive interconnect comprises a conductive layer on said contact point and said polymer layer, wherein said conductive layer comprises a copper-containing layer, a nickel layer on said conductive layer opposite said contact point, and a solder on said nickel layer.
2. The circuit component of claim 1 , wherein said conductive pad comprises copper.
3. The circuit component of claim 1 , wherein said polymer layer comprises polyimide.
4. The circuit component of claim 1 , wherein said via is aligned with said conductive pad and said solder.
5. The circuit component of claim 1 , wherein said nickel layer has a thickness between 1 to 10 micrometers.
6. The circuit component of claim 1 , wherein said conductive pad comprises aluminum.
7. The circuit component of claim 1 , wherein said circuit component is a wafer.
8. A circuit component comprising:
a semiconductor substrate;
a dielectric layer directly on said semiconductor substrate, wherein a via is in said dielectric layer and penetrates through said dielectric layer;
a conductive pad directly on said dielectric layer, said conductive pad coupled to said semiconductor substrate through said via;
a passivation layer on said dielectric layer and directly on a surface of said conductive pad opposite said dielectric layer, wherein a first opening in said passivation layer exposes a contact point of said conductive pad, in which a thickness of the conductive pad covered by the passivation layer is greater than a thickness of the conductive pad exposed by the first opening in the passivation layer;
a polymer layer on said passivation layer, wherein a second opening in said polymer layer exposes said contact point; and
a conductive interconnect on said contact point and said polymer layer, wherein said conductive interconnect is coupled to said contact point through said second opening, wherein said conductive interconnect comprises a conductive layer on said contact point and said polymer layer, wherein said conductive layer comprises a copper-containing layer, a nickel layer on said conductive layer and opposite said contact point, and a gold layer on said nickel layer.
9. The circuit component of claim 8 , wherein said polymer layer is further on said contact point and in said first opening.
10. The circuit component of claim 8 , wherein said polymer layer comprises polyimide.
11. The circuit component of claim 8 , wherein said via is aligned with said conductive pad and said gold layer.
12. The circuit component of claim 8 , wherein said nickel layer has a thickness between 1 and 10 micrometers.
13. The circuit component of claim 8 , wherein said conductive pad comprises aluminum.
14. The circuit component of claim 8 , wherein said circuit component is a wafer.
15. A circuit component comprising:
a semiconductor substrate;
a dielectric layer directly on said semiconductor substrate, wherein a first via is in said dielectric layer and penetrates through said dielectric layer;
a conductive pad directly on said dielectric layer and aligned with said first via, said conductive pad coupled to said semiconductor substrate through said via;
a passivation layer on said dielectric layer and directly on a surface of said conductive pad opposite said dielectric layer, wherein an opening in said passivation layer exposes a contact point of said conductive pad, in which a thickness of the conductive pad covered by the passivation layer is greater than a thickness of the conductive pad exposed by the first opening in the passivation layer;
a polymer layer on said passivation layer, wherein a second opening in said polymer layer exposes said contact point; and
a conductive interconnect on said contact point and said polymer layer and aligned with said first via, wherein said conductive interconnect is coupled to said contact point through said opening, wherein said conductive interconnect comprises a conductive layer on said contact point and said polymer layer, wherein said conductive layer comprises a copper-containing layer, a nickel layer on said conductive layer opposite said contact point, wherein said nickel layer has a thickness between 1 and 10 micrometers, and a solder coupled to said nickel layer, said contact point, said polymer layer and said first via.
16. The circuit component of claim 15 , wherein a second via in said dielectric layer is aligned with said conductive pad and said solder.
17. The circuit component of claim 15 , wherein said polymer layer is further on- and in contact with said conductive pad.
18. The circuit component of claim 15 , wherein said polymer layer comprises polyimide.
19. The circuit component of claim 15 , wherein said first via has a width less than that of said opening.
20. The circuit component of claim 15 , wherein said conductive pad comprises copper.
21. The circuit component of claim 15 , wherein said conductive pad comprises aluminum.
22. The circuit component of claim 15 , wherein said circuit component is a wafer.