Semiconductor package including a top-surface metal layer for implementing circuit features
View Patent ↗A semiconductor package including a top-surface metal layer for implementing circuit features provides improvements in top-surface interconnect density, more flexible routing and mounting of top surface semiconductor packages, dies and passive components or a conformal shield cap implementation. The metal layer interconnected with an internal substrate of the semiconductor package by blind vias laser-ablated through the encapsulation and filled with metal. The vias extend from the top surface to an internal package substrate or through the encapsulation to form bottom-side terminals. The metal layer may be formed by circuit patterns and/or terminals embedded within the encapsulation conformal to the top surface by laser-ablating channels in the top surface of the encapsulation and filling the channels with metal. A conformal coating may be applied to the top surface of the semiconductor package over the metal layer to prevent solder bridging to circuit patterns of the metal layer.
1. A method comprising:
mounting a semiconductor die on a top surface of a substrate;
covering the semiconductor die and the top surface of the substrate with an encapsulation;
laser-ablating via holes in the encapsulation;
laser-ablating channels in a top surface of the encapsulation;
depositing conductive material in the via holes to form vias; and
depositing conductive material in the channels to form a metal layer within the encapsulation at the top surface of the encapsulation.
2. The method of claim 1 wherein the via holes extend from the top surface of the encapsulation to electrical connections of the semiconductor die.
3. The method of claim 2 wherein the vias are directly connected to the electrical connections of the semiconductor die.
4. The method of claim 1 wherein the substrate comprises a circuit pattern on the top surface of the substrate.
5. The method of claim 4 wherein the via holes extend from the top surface of the encapsulation to the circuit pattern.
6. The method of claim 5 wherein the vias are directly connected to the circuit pattern.
7. The method of claim 4 further comprising electrically connecting electrical connections of the semiconductor die to the circuit pattern with wires.
8. The method of claim 1 wherein the substrate comprises lands on a bottom surface of the substrate.
9. The method of claim 8 wherein the via holes extend from the top surface of the encapsulation, through the encapsulation, through the substrate, and to a top surface of the lands.
10. The method of claim 8 wherein the via holes extend from the top surface of the encapsulation, through the encapsulation, through the substrate, and through the lands.
11. The method of claim 8 wherein the vias are directly connected to the lands.
12. The semiconductor package of claim 8 further comprising solder balls attached to the lands.
13. The method of claim 1 further comprising:
forming a solder mask over the top surface of the encapsulation and portions of the metal layer, the solder mask comprising openings therein that expose terminals of the metal layer.
14. The method of claim 1 wherein the metal layer is connected to the vias.
15. A method comprising:
mounting a semiconductor die on a top surface of a substrate;
covering the semiconductor die and the top surface of the substrate with an encapsulation;
laser-ablating via holes in the encapsulation;
laser-ablating a shield cavity in a top surface of the encapsulation;
depositing conductive material in the via holes to form vias; and
depositing conductive material in the shield cavity to form a metal shield layer within, the encapsulation at the top surface of the encapsulation.
16. The method of claim 15 wherein the metal shield layer is contained within sides of the encapsulation.
17. The method of claim 15 wherein a portion of the top surface of the encapsulation remains between the metal shield layer and the sides of the encapsulation.
18. A method comprising:
forming a bottom semiconductor package comprising:
laser-ablating via holes in an encapsulation of the bottom semiconductor package;
laser-ablating channels in a top surface of the encapsulation of the bottom semiconductor package;
depositing conductive material in the via holes to form vias; and
depositing conductive material in the channels to form a metal layer within the encapsulation at the top surface of the encapsulation, the metal layer comprising terminals; and
coupling a semiconductor die to the terminals of the metal layer.
19. The method of claim 18 wherein wires couple the semiconductor die to the terminals of the metal layer, the method further comprising:
applying a second encapsulation over the semiconductor die, the wires, and at least part of the top surface of the encapsulation.
20. The method of claim 18 wherein a top semiconductor package comprises the semiconductor die, the coupling a semiconductor die to the terminals of the metal layer comprising:
mounting solder balls of the top semiconductor package to the terminals of the metal layer.