Pillar structure having a non-planar surface for semiconductor devices
View Patent ↗A conductive pillar for a semiconductor device is provided. The conductive pillar is formed such that a top surface is non-planar. In embodiments, the top surface may be concave, convex, or wave shaped. An optional capping layer may be formed over the conductive pillar to allow for a stronger inter-metallic compound (IMC) layer. The IMC layer is a layer formed between solder material and an underlying layer, such as the conductive pillar or the optional capping layer.
1. A semiconductor structure comprising:
a substrate comprising a first conductive layer;
a pillar electrically coupled to the first conductive layer, the pillar having a non-planar upper surface; and
solder material overlying the pillar and in electrical contact with the first conductive layer, wherein a distance between an uppermost point of the non-planar upper surface and a lowermost point of the non-planar upper surface is about 6% of a width of the pillar.
2. The semiconductor structure of claim 1 , wherein the non-planar upper surface is a convex surface.
3. The semiconductor structure of claim 1 , wherein the non-planar upper surface is a concave surface.
4. The semiconductor structure of claim 1 , wherein the non-planar upper surface has a wave shape.
5. The semiconductor structure of claim 1 , further comprising a capping layer interposed between the pillar and the solder material.
6. The semiconductor structure of claim 5 , wherein the capping layer is formed of Ni, Pt, Au, or Ag.
7. The semiconductor structure of claim 6 wherein the capping layer is formed from a first material selected to result in an IMC stronger than a second IMC resulting from a second material forming the pillar.
8. The semiconductor structure of claim 1 , further comprising an inter-metallic compound (IMC) layer interposed between the pillar and the solder material, a thickness of the IMC layer being less than about the distance between the uppermost point of the non-planar upper surface and the lowermost point of the non-planar upper surface.
9. A structure comprising:
a pillar electrically coupled to a first conductive layer, the pillar having a non-planar upper surface;
solder material overlying the pillar and in electrical contact with the first conductive layer, wherein a distance between an uppermost point of the non-planar upper surface and a lowermost point of the non-planar upper surface is about 6% of a width of the pillar; and
a capping layer interposed between the pillar and the solder material.
10. The structure of claim 9 , wherein a distance between an uppermost point of the non-planar upper surface and the lowermost point of the non-planar upper surface is a roughness of the non-planar upper surface.
11. The structure of claim 9 , wherein the non-planar upper surface is one of a convex shape and a concave shape.
12. The structure of claim 11 , further comprising an inter-metallic compound (IMC) layer interposed between the capping layer and the solder material.
13. The structure of claim 12 , wherein the capping layer is formed of Ni, Pt, Au, or Ag.
14. The structure of claim 12 wherein the capping layer is formed from a first material selected to result in an IMC stronger than a second IMC resulting from a second material forming the pillar.
15. The structure of claim 12 , wherein a thickness of the IMC layer is less than about 6 μm, and the distance between an uppermost point of the non-planar upper surface and the lowermost point of the non-planar upper surface is greater than about 6 μm.
16. A structure comprising:
a pillar electrically formed of a first conductive material, the pillar having a non-planar upper surface;
solder material overlying the pillar and in electrical contact with the pillar;
an inter-metallic compound (IMC) layer interposed between the pillar and the solder material;
wherein a thickness of the IMC layer is less than about 6 μm, and a distance between an uppermost point of the non-planar upper surface and a lowermost point of the non-planar upper surface is greater than about 6 μm; and
wherein the pillar has a width such that the distance between the uppermost point of the non-planar upper surface and the lowermost point of the non-planar upper surface is about 6% of the width of the pillar.
17. The structure of claim 16 , further comprising a capping layer disposed between the IMC and the pillar.
18. The structure of claim 17 , wherein the capping layer is formed of Ni, Pt, Au, or Ag.
19. The structure of claim 17 wherein the capping layer is formed from a second material selected to result in an IMC stronger than an IMC formed from the first conductive material forming the pillar.