Alternative surfaces for conductive pad layers of silicon bridges for semiconductor packages
Alternative surfaces for conductive pad layers of silicon bridges for semiconductor packages, and the resulting silicon bridges and semiconductor packages, are described. In an example, a semiconductor structure includes a substrate having a lower insulating layer disposed thereon. The substrate has a perimeter. A metallization structure is disposed on the lower insulating layer. The metallization structure includes conductive routing disposed in a dielectric material stack. First and second pluralities of conductive pads are disposed in a plane above the metallization structure. Conductive routing of the metallization structure electrically connects the first plurality of conductive pads with the second plurality of conductive pads. An upper insulating layer is disposed on the first and second pluralities of conductive pads. The upper insulating layer has a perimeter substantially the same as the perimeter of the substrate.
1. A method of fabricating a plurality of silicon bridge dies, the method comprising:
providing a wafer having a plurality of silicon bridge dies thereon, each of the plurality of silicon bridge dies having an uppermost layer of copper pads exposed;
forming a silicon nitride layer on the wafer, the silicon nitride layer covering the uppermost layer of copper pads of the plurality of silicon bridge dies; and
singulating the plurality of silicon bridge dies by sawing along scribe lines of the wafer, through the silicon nitride layer.
2. The method of claim 1 , wherein forming the silicon nitride layer on the wafer comprises forming the silicon nitride layer without substantially thinning the uppermost layer of copper pads prior to the forming the silicon nitride layer.
3. The method of claim 1 , wherein forming the silicon nitride layer comprises forming a layer selected from the group consisting of a silicon rich silicon nitride layer, a silicon poor silicon nitride layer, and a stoichiometric silicon nitride layer (Si 3 N 4 ).
4. The method of claim 1 , further comprising:
subsequent to singulating the plurality of silicon bridge dies, forming a plurality of holes in the silicon nitride layer, the plurality of holes exposing copper pads of the uppermost layer of copper pads.
5. The method of claim 1 , wherein forming the silicon nitride layer on the wafer comprises forming the silicon nitride layer on the uppermost layer of copper pads and on a layer of silicon oxide in which the uppermost layer of copper pads is formed.
6. A method of fabricating a semiconductor structure, the method comprising:
providing a substrate having a lower insulating layer disposed thereon, the substrate having a perimeter, the perimeter having a first side and a second side laterally opposite the first side from a cross-sectional perspective;
forming a metallization structure disposed on the lower insulating layer, the metallization structure comprising conductive routing disposed in a dielectric material stack;
forming a conductive pad disposed in a plane above the metallization structure, the conductive pad electrically coupled to the conductive routing of the metallization structure;
forming a conductive structure laterally adjacent to the metallization structure and the conductive pad, the conductive structure comprising a vertically dense arrangement of lines and vias aligned along a common axis; and
forming an upper insulating layer disposed on the conductive pad, the upper insulating layer having a perimeter substantially the same as the perimeter of the substrate, the upper insulating layer having a hole exposing only a portion of the conductive pad, and the upper insulating layer entirely covering the conductive structure, wherein an entirety of the upper insulating layer has a uniform thickness and is planar, and wherein the upper insulating layer is entirely within the first side and the second side of the perimeter from the cross-sectional perspective.
7. The method of claim 6 , wherein the upper insulating layer is a layer of silicon nitride.
8. The method of claim 7 , wherein the layer of silicon nitride is a layer selected from the group consisting of a silicon rich silicon nitride layer, a silicon poor silicon nitride layer, and a stoichiometric silicon nitride layer (Si 3 N 4 ).
9. The method of claim 7 , wherein the layer of silicon nitride has a thickness approximately in the range of 75-150 nanometers.
10. The method of claim 6 , wherein the conductive pad has a thickness of approximately 2 microns.
11. The method of claim 6 , wherein the conductive pad comprises copper.
12. The method of claim 6 , wherein the metallization structure comprises a bottommost metal line layer disposed on the lower insulating layer, intermediate layers of alternating metal line layers and via layers disposed on the bottommost metal line layer, and an uppermost metal line layer disposed on the intermediate layers of alternating metal line layers and via layers.
13. The method of claim 12 , wherein the conductive pad is disposed on a layer comprising a terminal via structure disposed in a second intermediate insulating layer, and wherein the terminal via structure couples the conductive pad to the uppermost metal line layer of the metallization structure.
14. The method of claim 6 , wherein the conductive pad is disposed in a layer of silicon oxide.
15. The method of claim 6 , wherein the semiconductor structure is a silicon bridge.
16. The method of claim 6 , wherein the substrate is free from having semiconductor devices disposed therein.