Semiconductor package signal routing using conductive vias
View Patent ↗A mechanism is provided by which signal travel distance within and between semiconductor device packages is reduced and substrate size and complexity can be reduced. This capacity is provided by virtue of a conductive via that intersects a wire bond molded within a package substrate. The via provides a direct electrical connection between an external signal transmitter or receiver and the points connected by the wire bond, and thereby avoiding the need for the signal to transit built up interconnects in the semiconductor device package. Conductive vias can provide connectivity through or to a package substrate, and can be through vias or blind vias. The conductive via is formed by either mechanical or laser drilling, and is filled using standard fill techniques, and is therefore readily incorporated into a package production flow.
1. A method for packaging an electronic device assembly, the method comprising:
electrically coupling an electronic device to one or more signal pads, wherein said electrically coupling is performed using corresponding wire bonds;
forming an encapsulant over and around sides of the electronic device and over and around the wire bonds and signal pads to provide an encapsulated electronic device assembly, wherein the encapsulated electronic device assembly comprises a first and second opposing major surfaces;
drilling a hole from one of the first or second major surface toward the opposing major surface, wherein the hole severs a wire bond electrically coupling the electronic device to a signal pad of the one or more signal pads; and
filling the hole with a conductive material to form a conductive via having a contact surface at or near the major surface from which the hole is drilled, wherein
the conductive via is in electrical contact with severed ends of the severed wire bond, and
the conductive via electrically couples the contact surface with the severed ends of the severed wire bond.
2. The method of claim 1 further comprising:
providing a package substrate comprising the one or more signal pads; and
placing the electronic device in an area of the package substrate for the electronic device assembly, wherein
said forming the encapsulant further comprises forming the encapsulant over the package substrate in the area for the electronic device assembly, and
the first major surface of the encapsulated device assembly comprises the package substrate.
3. The method of claim 2 wherein said drilling the hole from one of the first or second major surface comprises drilling the hole through the package substrate from the first major surface.
4. The method of claim 3 further comprising:
forming a first solder ball on the first major surface of the electronic device assembly subsequent to said forming the encapsulant, wherein the first solder ball is coupled to a signal contact on the package substrate; and
forming a second solder ball on the contact surface of the conductive via.
5. The method of claim 2 wherein said drilling the hole from one of the first or second major surface comprises drilling the hole from the second major surface to the package substrate but not through the package substrate.
6. The method of claim 5 wherein said filling the hole with a conductive material further forms the conductive via electrically coupled with a signal contact on the package substrate.
7. The method of claim 1 , wherein
said drilling the hole from one of the first or second major surface toward the opposing major surface further comprises drilling the hole through the opposing major surface, and
said filling the hole with a conductive material forms a through via further having a second contact surface at or near the major surface opposing the major surface from which the hole is drilled.
8. The method of claim 1 further comprising:
placing a second electronic device assembly on one of the first or second major surface of the encapsulated electronic device assembly from which the hole is drilled; and
forming an electrical connection between a signal contact on the second electronic device assembly and the contact surface of the conductive via of the encapsulated electronic device assembly.
9. The method of claim 8 wherein said forming the electrical connection comprises using a solder ball between the signal contact on the second electronic device assembly and the contact surface.
10. The method of claim 8 wherein said forming the electrical connection comprises performing a solder reflow.
11. The method of claim 1 wherein the wire bond comprises one or more of gold, copper, aluminum, and palladium.
12. The method of claim 1 wherein the conductive material forming the conductive via comprises a solder paste.
13. The method of claim 1 further comprising:
providing a lead frame comprising the one or more signal pads and a die pad; and
placing the electronic device on the die pad, wherein
said forming the encapsulant further comprises forming the encapsulant over the lead frame and around sides of the lead frame, and
the first major surface of the encapsulated device assembly comprises the lead frame.