Semiconductor device package having backside contact and method for manufacturing
View Patent ↗A method and apparatus for forming a backside contact, electrical and/or thermal, for die encapsulated in a semiconductor device package are provided. Die of varying thicknesses can be accommodated within the semiconductor device package. Embodiments of the present invention provide a conductive pedestal coupled to a backside contact of a die, where the coupling is performed prior to encapsulating the die within the package. In addition, conductive pedestals coupled to varying die within a semiconductor device package are of such a thickness that each conductive pedestal can be exposed on the back side of the package without exposing or damaging the backside of any encapsulated die. Embodiments of the present invention provide for the conductive pedestals being made of electrically or thermally conductive material and coupled to the device die contact using an electrically and/or thermally conductive adhesive.
1. A method for packaging an electronic device assembly, the method comprising:
coupling a conductive pedestal to a die contact of an electronic device die to form a first die-pedestal assembly, wherein
the conductive pedestal comprises a first major surface coupled to the die contact and a second major surface opposite the first major surface, and
an area of the first major surface is less than an area of the electronic device die major surface comprising the die contact,
said coupling comprises holding a lead frame on a carrier wherein the lead frame comprises a plurality of conductive pedestals coupled to one another by one or more spars and the plurality of conductive pedestals comprises the conductive pedestal, applying a conductive adhesive to the first major surface of the conductive pedestal, and placing the electronic device die on the conductive adhesive wherein the die contact is in contact with the conductive adhesive;
placing the first die-pedestal assembly in a first area for the electronic device assembly;
forming an encapsulant over and around sides of the first die-pedestal assembly; and
exposing the second major surface of the conductive pedestal.
2. The method of claim 1 wherein the conductive pedestal comprises one or more of copper, nickel, gold, aluminum, ceramic, and a metal alloy.
3. The method of claim 1 wherein said coupling further comprises:
performing a curing operation to set the conductive adhesive.
4. The method of claim 3 wherein the conductive adhesive comprises solder and the curing operation comprises a solder reflow.
5. The method of claim 3 wherein the conductive adhesive comprises conductive epoxy and the curing operation comprises heating the region comprising the conductive epoxy.
6. The method of claim 1 further comprising:
separating the conductive pedestal from the plurality of conductive pedestals by cutting the spars, wherein said cutting is performed such that any burrs from remaining spar material are retained within an area defined by the electronic device die.
7. The method of claim 1 wherein said coupling comprises:
holding the electronic device die such that the die contact is accessible;
applying a conductive adhesive to the electronic device die surface comprising the die contact;
placing the conductive pedestal on the conductive adhesive such that the conductive pedestal is one or more of directly in contact with the die contact or in electrical or thermal contact with the die contact by virtue of the conductive adhesive.
8. The method of claim 1 wherein said coupling provides one or more of an electronic coupling or a thermal coupling.
9. The method of claim 1 further comprising:
coupling a heat sink to the second major surface of the pedestal, wherein
said coupling the heat sink is performed subsequent to said exposing, and
the die contact is a thermal contact.
10. The method of claim 1 further comprising:
coupling a second electronic device contact to the second major surface of the conductive pedestal, wherein
said coupling the second electronic device contact is performed subsequent to said exposing, and
the die contact is an electronic contact.
11. The method of claim 1 further comprising:
placing a second die-pedestal assembly in a second area for the electronic device assembly, wherein
a combined thickness of the second die-pedestal assembly is not the same as a combined thickness of the first die-pedestal assembly,
the encapsulant is further formed over and around sides of the second die-pedestal assembly; and
performing said exposing to expose both the free major surface of the conductive pedestal and a conductive pedestal of the second die-pedestal assembly.
12. The method of claim 11 wherein said performing said exposing comprises:
performing a back grind operation to a depth sufficient to expose the free surface of the shortest of the conductive pedestals of the first and second die-pedestal assemblies.