Methods and apparatus for transmission lines in packages
Methods and apparatus for forming a semiconductor device package with a transmission line using a micro-bump layer are disclosed. The micro-bump layer may comprise micro-bumps and micro-bump lines, formed between a top device and a bottom device. A signal transmission line may be formed using a micro-bump line above a bottom device. A ground plane may be formed using a redistribution layer (RDL) within the bottom device, or using additional micro-bump lines. The RDL formed ground plane may comprise open slots. There may be RDLs at the bottom device and the top device above and below the micro-bump lines to form parts of the ground planes.
1. A device comprising:
a first substrate;
a first insulator layer over the first substrate;
a redistribution layer over the first insulator layer, the redistribution layer comprising a first redistribution line and a second redistribution line;
a second insulator layer over the redistribution layer;
a micro-bump layer over the second insulator layer, the micro-bump layer comprising a micro-bump line and a micro-bump structure, wherein the micro-bump line is laterally above the first redistribution line and the micro-bump structure contacts the second redistribution line, wherein the micro-bump line and the micro-bump structure comprise a same one or more layers, wherein the micro-bump line and the micro-bump structure each comprise a layer of solder material;
a second substrate coupled to the micro-bump structure; and
an underfill interposed between the second insulator layer and the second substrate, the underfill completely separating the micro-bump line and the second substrate.
2. The device of claim 1 , wherein a width of the micro-bump line is less than a width of the first redistribution line, the micro-bump line being a signal transmission line and the first redistribution line being coupled to a ground plane.
3. The device of claim 1 , wherein a width of the micro-bump line is greater than a width of the first redistribution line, the micro-bump line being coupled to a ground plane and the first redistribution line being coupled to a signal transmission line.
4. The device of claim 1 , wherein the redistribution layer further comprises a third redistribution line, wherein the micro-bump line overlaps the first redistribution line and the third redistribution line, a width of the micro-bump line is less than a combined width of the first redistribution line and the third redistribution line, the micro-bump line being coupled to signal transmission line, wherein the first redistribution line and the third redistribution line are coupled to a ground plane.
5. The device of claim 1 , wherein the first redistribution line comprises one or more slots.
6. The device of claim 1 , wherein the micro-bump line and the micro-bump structure each comprise a layer of copper.
7. The device of claim 1 , wherein the micro-bump line and the micro-bump structure comprises an under bump metallization (UBM).
8. A device comprising:
a first substrate having a redistribution line and a first insulator layer;
a micro-bump layer comprising a micro-bump line and a micro-bump structure, wherein the first insulator layer is interposed between the redistribution line and the micro-bump line, each of the micro-bump line and the micro-bump structure comprising both one or more metallic layers and a solder layer on the one or more metallic layers, wherein the one or more metallic layers is interposed between the solder layer and the first insulator layer;
a second substrate bonded to the micro-bump structure by the solder layer; and
an underfill interposed between the micro-bump line and the second substrate, the underfill completely separating the micro-bump line and the second substrate.
9. The device of claim 8 , wherein the redistribution line comprises slots.
10. The device of claim 9 , wherein a longitudinal axis of the slots are perpendicular to a longitudinal axis of the micro-bump line.
11. The device of claim 10 , wherein the slots are wider than the micro-bump line in a plan view.
12. The device of claim 8 , wherein the micro-bump layer further comprises a first micro-bump ground line and a second micro-bump ground line, wherein the micro-bump line is laterally interposed between the first micro-bump ground line and the second micro-bump ground line.
13. The device of claim 12 , wherein the redistribution line extends under the first micro-bump ground line and the second micro-bump ground line.
14. The device of claim 8 , wherein the redistribution line and the micro-bump line are on opposite sides of the first substrate.
15. A device comprising:
a micro-bump layer on a first substrate, the micro-bump layer comprising one or more micro-bump lines and a micro-bump structure, wherein each of the one or more micro-bump lines and the micro-bump structure have a same conductive layer structure, wherein the conductive layer structure of both the one or more micro-bump lines and the micro-bump structure comprises a solder layer;
a redistribution line below the micro-bump layer;
a first insulator layer interposed between the redistribution line and the micro-bump layer;
a second substrate coupled to the micro-bump structure by the solder layer of the micro-bump structure; and
an underfill interposed between the micro-bump line and the second substrate, wherein the underfill extends closer to the second substrate than the one or more micro-bump lines.
16. The device of claim 15 , wherein the redistribution line comprises a plurality of lines connected to ground, wherein a first micro-bump line of the micro-bump lines comprises a signal micro-bump line, wherein a width of the redistribution line is greater than a width of the signal micro-bump line.
17. The device of claim 15 , wherein a plurality of the micro-bump lines are electrically coupled to the redistribution line.
18. The device of claim 15 , wherein the redistribution line comprises slots.
19. The device of claim 18 , wherein a plurality of the micro-bump lines are coupled the redistribution line, wherein the redistribution line is coupled to ground.
20. The device of claim 15 , wherein the redistribution line is coupled to ground, the one or more micro-bump lines comprise is a signal line, and the first substrate is interposed between the redistribution line and the signal line.