Through via connected backside embedded circuit features structure and method
View Patent ↗A method includes forming through vias in a substrate of an array. Nubs of the through vias are exposed from a backside surface of the substrate. A backside passivation layer is applied to enclose the nubs. Laser-ablated artifacts are formed in the backside passivation layer to expose the nubs. Circuit features are formed within the laser-ablated artifacts. By forming the circuit features within the laser-ablated artifacts in the backside passivation layer, the cost of fabricating the array is minimized. More particularly, the number of operations to form the embedded circuit features is minimized thus minimizing fabrication cost of the array.
1. A structure comprising:
a substrate comprising a backside surface;
through vias comprising nubs extending from the backside surface;
a backside passivation layer coupled to the backside surface, the backside passivation layer comprising only a single layer of material; and
circuit features embedded within the backside passivation layer and coupled to the nubs, the circuit features comprising recessed surfaces, at least a portion of the backside passivation layer between the recessed surfaces and a first passivation layer surface of the backside passivation layer.
2. The structure of claim 1 , comprising a respective via passivation lining between the backside passivation layer and at least a portion of each of the nubs.
3. The structure of claim 1 , wherein the nubs are generally of the same diameter as the through vias.
4. A structure comprising:
a substrate;
through vias in the substrate, nubs of the through vias being exposed from a backside surface of the substrate;
a backside passivation layer comprising a first passivation layer surface directly coupled to the backside surface of the substrate;
laser-ablated artifacts in the backside passivation layer, the laser-ablated artifacts comprising recessed surfaces, the backside passivation layer remaining between the recessed surfaces and the first passivation layer surface, the nubs protruding from the recessed surfaces into the laser-ablated artifacts; and
an electrically conductive material filling the laser-ablated artifacts.
5. The structure of claim 4 , wherein the electrically conductive material comprises a single conductive layer that fills the laser-ablated artifacts.
6. The structure of claim 5 wherein the single conductive layer fills the laser-ablated artifact and extends beyond the backside passivation layer.
7. The structure of claim 5 wherein the circuit features are entirely embedded in the backside passivation layer.
8. The structure of claim 5 wherein the laser-ablated artifacts comprise a land opening and the circuit features comprise a land in the land opening.
9. The structure of claim 5 wherein the laser-ablated artifacts comprise a trace channel and the circuit features comprise a trace in the trace channel.
10. The structure of claim 5 wherein the backside passivation layer comprises a single continuous layer applied directly to the backside surface of the substrate and to the nubs.
11. The structure of claim 10 wherein the single continuous layer is thicker than a distance to which the nubs protrude from the substrate.
12. The structure of claim 4 wherein the laser-ablated artifacts expose the nubs.
13. The structure of claim 4 , wherein:
the backside passivation layer comprises a second passivation layer surface opposite to and parallel to the first passivation layer surface; and
the laser-ablated artifacts extend from the second passivation layer surface to a base surface that is between the first and second passivation layer surfaces.
14. The structure of claim 4 wherein the electrically conductive material forms electrically conductive circuit features partially embedded in the backside passivation layer and extending onto a surface of the backside passivation layer.
15. A structure comprising:
a substrate;
through vias in the substrate, nubs of the through vias being exposed from a backside surface of the substrate;
a backside passivation layer directly coupled to the backside surface of the substrate; and
circuit features at least partially embedded in the backside passivation layer, the circuit features being coupled to the nubs, the circuit features comprising recessed surfaces, the backside passivation layer remaining between the recessed surfaces and a first passivation layer surface of the backside passivation layer, the nubs protruding from the recessed surfaces into the circuit features.
16. The structure of claim 15 further comprising:
laser-ablated artifacts in the backside passivation layer, the circuit features being within the laser-ablated artifacts.
17. The structure of claim 15 wherein the circuit features are selected from the group consisting of lands, traces, and vias.
18. The structure of claim 15 wherein the through vias comprise through via passivation linings and through via columns, the nubs comprising portions of the through via passivation linings and the through via columns exposed from the backside surface of the substrate.
19. The structure of claim 15 wherein the through vias comprise through via passivation linings and through via columns, the nubs consisting of portions of the through via columns exposed from the backside surface of the substrate.
20. The structure of claim 15 wherein the nubs comprise upper rounded ends.