Semiconductor package and substrate having multi-level vias
View Patent ↗A semiconductor package and substrate having multi-level plated vias provide a high density blind via solution at low incremental cost. Via are half-plated atop a circuit pattern and then a second via half is added to complete the via after isolation of elements of the circuit pattern. Successive resist pattern applications and etching are used to form a via tier atop a circuit pattern that is connected by a thin plane of metal. After the tier is deposited, the thin metal plane is etched to isolate the circuit pattern elements. Dielectric is then deposited and the top half of the via is deposited over the tier. The tier may have a larger or smaller diameter with respect to the other half of the via, so that the via halves may be properly registered. Tin plating may also be used to control the etching process to provide etching control.
1. A substrate for mounting at least one die within a semiconductor package, comprising:
a first dielectric layer having a metal circuit pattern formed on a first face thereof;
a second dielectric layer having a first face bonded to the first face of the first dielectric layer, whereby the metal circuit pattern is covered; and
blind vias extending within the second dielectric layer from and perpendicular to a second face of the second dielectric layer inward to the circuit pattern, wherein the blind vias including a tier portion extending partially through the second dielectric layer from the circuit pattern to an interface with a partial via portion extending from the interface to the second face of the second dielectric layer, and wherein the partial via portion has a diameter differing from that of the tier portion, whereby registration of the interface is facilitated.
2. The substrate of claim 1 , wherein the tier portion is formed from copper plated atop the circuit pattern.
3. The substrate of claim 2 , wherein the partial via portion is formed from copper plated atop the tier portion.
4. The substrate of claim 2 , wherein the partial via portion is formed from a conductive paste added atop the tier portion.
5. The substrate of claim 1 , wherein the partial via portion extends through a laser-ablated void formed in the second dielectric layer.
6. The substrate of claim 1 , further comprising a first metal plating layer of dissimilar metal from the circuit pattern between the circuit pattern and the tier portion.
7. The substrate of claim 6 , further comprising a second metal plating layer of the dissimilar metal from the circuit pattern between the partial via portion and the tier portion.
8. The substrate of claim 7 , wherein the circuit pattern and the tier portion are plated copper and wherein the first metal plating layer and the second metal plating layer are tin.
9. The substrate of claim 1 , further comprising a metal plating layer of dissimilar metal from the circuit pattern between the partial via portion and the tier portion.
10. A semiconductor package, comprising:
a substrate having a circuit pattern embedded therein with vias extending from the circuit pattern to a face of the substrate, wherein the vias include a tier portion extending from the circuit pattern to an interface with a half via portion extending from the interface to the face of the substrate, and wherein the diameter of the half via portion differs from the diameter of the tier portion;
a die mounted to the substrate; and
a plurality of electrical terminals mounted to the substrate for connecting the die to external circuits.
11. The semiconductor package of claim 10 , wherein the tier portion is formed from copper plated atop the circuit pattern.
12. The semiconductor package of claim 11 , wherein the partial via portion is formed from copper plated atop the tier portion.
13. The semiconductor package of claim 11 , wherein the partial via portion is formed from a conductive paste added atop the tier portion.
14. The semiconductor package of claim 10 , further comprising a first metal plating layer of dissimilar metal from the circuit pattern between the circuit pattern and the tier portion.
15. The semiconductor package of claim 14 , further comprising a second metal plating layer of the dissimilar metal from the circuit pattern between the partial via portion and the tier portion.
16. A substrate for mounting at least one die within a semiconductor package, comprising:
a first dielectric layer having a metal circuit pattern formed on a first face thereof;
a second dielectric layer having a first face bonded to the first face of the first dielectric layer, whereby the metal circuit pattern is covered; and
blind vias extending within the second dielectric layer from and perpendicular to a second face of the second dielectric layer inward to the circuit pattern, wherein the blind vias include means for reducing a plating height from the circuit pattern required to plate the via above the circuit pattern and means for completing the via from an end of the means for reducing to the second face of the second dielectric layer.
17. The substrate of claim 16 , further comprising means for preventing removal of the circuit pattern during an etching process, wherein the means for preventing removal is located between the circuit pattern and the means for reducing.
18. The substrate of claim 16 , further comprising means for preventing removal of the means for reducing during an etching process, wherein the means for preventing removal is located between the means for reducing and the means for completing the via.
19. A substrate for mounting at least one die within a semiconductor package, comprising:
at least one dielectric layer;
a metal circuit pattern within said at least one dielectric layer whereby said at least one dielectric layer encloses said metal circuit pattern; and
a blind via extending within the at least one dielectric layer from the circuit pattern to an external surface of the at least one dielectric layer, wherein said blind via comprises a first metal segment having a first cross-sectional width and a second metal segment having a second cross-sectional width substantially differing from said first cross-sectional width.
20. The substrate of claim 19 , wherein said blind via further comprises a third metal segment of material differing from that of said first metal segment and said second metal segment disposed between and electrically connecting said first metal segment and said second metal segment.