Skip-level TSV with hybrid dielectric scheme for backside power delivery
A skip-level through-silicon via structure is provided that enables low resistance via connection for backside power distribution by skipping one or more intermediate backside metal layers. The skip-level through-silicon via structure can enable a greater design flexibility for power grid. The skip-level through-silicon via structure has a large size that provides lower through-silicon via resistance as compared with conventional through-silicon via structures.
1. A semiconductor structure comprising:
a skip-level through-silicon via structure having a first portion, a second portion, a first surface and a second surface opposite the first surface, wherein the first portion and the second portion are in direct physical contact with each other;
a semiconductor substrate located laterally adjacent to the first portion of the skip-level through-silicon via structure;
a dielectric barrier layer separating the semiconductor substrate from the first portion of the skip-level through-silicon via structure;
a backside dielectric material region located laterally adjacent to, and in direct physical contact with, a sidewall of the second portion of the skip-level through-silicon via structure;
a buried power rail located in the semiconductor substrate and in electrical contact with the first surface of the skip-level through-silicon via structure; and
an n+1 backside metal layer located in the backside dielectric material region and in electrical contact with the second surface of the skip-level through-silicon via structure, wherein the skip-level through-silicon via structure skips electrical connection with each intermediate backside metal layer located above the n+1 backside metal layer.
2. The semiconductor structure of claim 1 , wherein the first portion of the skip-level through-silicon via structure has a width that is less than a width of the second portion of the skip-level through-silicon via structure.
3. The semiconductor structure of claim 1 , wherein n is 1, and the skip-level through-silicon via structure skips electrical connection to a first backside metal layer.
4. The semiconductor structure of claim 1 , wherein n is 2, and the skip-level through-silicon via structure skips electrical connection to a first backside metal layer and a second backside metal layer.
5. The semiconductor structure of claim 1 , wherein each intermediate backside metal layer located above the n+1 backside metal layer is located in the backside dielectric material region.
6. The semiconductor structure of claim 1 , wherein the backside dielectric material region is located beneath the semiconductor substrate and forms a material interface with a surface of the semiconductor substrate.
7. The semiconductor structure of claim 1 , wherein a portion of the dielectric barrier layer contacts a sidewall of the backside dielectric material region.
8. The semiconductor structure of claim 1 , wherein the buried power rail has a width that is greater than a width of the first portion of the skip-level through-silicon via structure.
9. The semiconductor structure of claim 1 , wherein the skip-level through-silicon via structure is composed of an electrically conductive metal or an electrically conductive metal alloy.
10. The semiconductor structure of claim 1 , wherein the n+1 backside metal layer has a width greater than a width of the second portion of the skip-level through-silicon via structure.
11. The semiconductor structure of claim 1 , further comprising a non-skip-level through-silicon via structure located in the semiconductor substrate and spaced apart from the skip-level through-silicon via structure, wherein the non-skip-level through-silicon via structure is separated from the semiconductor substrate by another dielectric barrier layer.
12. The semiconductor structure of claim 11 , wherein the non-skip-level through-silicon via structure has a first surface in electrical contact with the buried power rail, and a second surface opposite the first surface that is in electrical contact with a first backside metal layer that comprises one of the intermediate backside metal layers.
13. The semiconductor structure of claim 12 , wherein an electrically conductive via structure electrically connects the first backside metal layer to a second backside metal layer, wherein the second backside metal layer is the n+1 backside metal layer.
14. The semiconductor structure of claim 1 , wherein the n+1 backside metal layer and each intermediate backside metal layer are composed of a backside metal or backside metal alloy.
15. The semiconductor structure of claim 1 , wherein each intermediate backside metal layer is spaced apart from the skip-level through-silicon via structure and from the n+1 backside metal layer by the backside dielectric material region.