Probe pad with indentation
An integrated electronic circuit having probe indentations filled by a hard covering substance. The integrated circuit device results from a process of manufacture including forming a substrate comprising a plurality of functional components of the electronic circuit, creating a plurality of conductive layers on such substrate to form an electric contact region with high hardness equal to or greater than a first hardness value of about 300 HV, contacting the electric contact region with a probe thereby causing an indentation. In an embodiment, the process further comprises, after the test run, creating a covering conductive layer on at least one part of the electric contact region contacted by the probe to fill the indentation.
1. An integrated circuit, comprising:
a substrate; and
a conductive pad disposed over the substrate and including:
a first conductive layer having an indentation, and
a second conductive layer disposed over the first conductive layer and having an opening that is aligned with the indentation, and
a third conductive layer disposed over the first and second conductive layers filling the indentation in the first conductive layer and the opening in the second conductive layer, the third conductive layer being at least coplanar with a top surface of the second conductive layer.
2. The integrated circuit of claim 1 wherein the first conductive layer consisting essentially of nickel.
3. The integrated circuit of claim 1 wherein the first conductive layer is harder than the second conductive layer.
4. The integrated circuit of claim 1 wherein the first conductive layer has a hardness within a range of 350 and 1100 HV.
5. The integrated circuit of claim 1 wherein the first conductive layer has a thickness within a range of 2 to 20 μm.
6. The integrated circuit of claim 1 wherein the indentation comprises a probe mark.
7. The integrated circuit of claim 1 wherein the second conductive layer comprises palladium.
8. The integrated circuit of claim 1 wherein the second conductive layer comprises gold.
9. The integrated circuit of claim 1 wherein the second conductive layer is disposed over a portion of the first conductive layer beyond the indentation.
10. The integrated circuit of claim 1 , wherein the third conductive layer is disposed over a portion of the first conductive layer beyond the indentation and over a portion of the second conductive layer beyond the opening.
11. The integrated circuit of claim 1 , wherein the second conductive layer has a thickness that is between 2% and 15% of the thickness of the first conductive layer.
12. The integrated circuit of claim 1 , further comprising:
a passivation layer disposed over the substrate adjacent to the conductive pad and having a top surface; and
wherein the third conductive layer has a top surface that is coplanar with the top surface of the passivation layer.
13. The integrated circuit of claim 1 , further comprising a wire bond disposed over the indentation.
14. The integrated circuit of claim 1 , further comprising a wire bond in contact with the third conductive layer.
15. The integrated circuit of claim 1 , further comprising a circuit disposed in the substrate and coupled to the conductive pad.
16. The integrated circuit of claim 1 , further comprising a package within which the substrate and the conductive pad are disposed.
17. An integrated circuit, comprising:
a substrate; and
a conductive pad disposed over the substrate and including:
a first conductive layer having an indentation,
a second conductive layer disposed covering the first conductive layer, and
a cavity extending through the second conductive layer and aligned with the indentation in the first conductive layer, and
a third conductive layer that fills the cavity and covers the first and second conductive layers to form a substantially planar surface above the second conductive layer for receiving a wire bond.
18. The integrated circuit of claim 17 , wherein the second conductive layer has a thickness that is between 2% and 15% of a thickness of the first conductive layer.
19. The integrated circuit of claim 17 , further comprising:
a passivation layer disposed over the substrate adjacent to the conductive pad and having a top surface; and
wherein the third conductive layer has a top surface that is coplanar with the top surface of the passivation layer.
20. The integrated circuit of claim 17 wherein the first conductive layer consists essentially of nickel.
21. The integrated circuit of claim 17 wherein the first conductive layer is harder than the second conductive layer.
22. The integrated circuit of claim 17 wherein the first conductive layer has a hardness within a range of 350 and 1100 HV.