Air cavity package with copper heat sink and ceramic window frame
An air cavity package is manufactured by attaching a die to a surface of a copper heat sink, dispensing a bead of epoxy around a periphery of the heat sink surface after the die is attached to the copper heat sink so that the bead of epoxy generally surrounds the die and placing a ceramic window frame on the bead of epoxy. The epoxy is cured to attach a bottom surface of the ceramic window frame to the copper heat sink.
1. An air cavity package, comprising:
a copper heat sink having a thermal conductivity of at least 350 W/mK;
a die attached to a surface of the copper heat sink;
a ceramic window frame having a bottom surface attached to a periphery of the heat sink surface via a cured epoxy, the ceramic window frame generally surrounding the die; and
a fillet formed from a portion of the cured epoxy disposed along an outer sidewall of the ceramic window frame facing away from the die, the fillet extending over at least 25% of the height of the outer sidewall of the ceramic window frame as measured from the heat sink surface.
2. The air cavity package of claim 1 , wherein the cured epoxy has a thickness that is equal to or less than 8 mils in a region under the bottom surface of the ceramic window frame.
3. The air cavity package of claim 1 , wherein the heat sink is plated with a metal that comprises Au.
4. The air cavity package of claim 1 , further comprising an additional fillet formed from a portion of the cured epoxy disposed along an inner sidewall of the ceramic window frame facing toward the die.
5. The air cavity package of claim 1 , wherein the cured epoxy has a cure temperature above 125° C., but less than about 265° C.
6. The air cavity package of claim 5 , wherein the cured epoxy has a cure temperature above 200° C., but less than about 265° C.
7. The air cavity package of claim 1 , wherein the ceramic window frame comprises 95% alumina.
8. The air cavity package of claim 1 , wherein the copper heat sink is plated with a Ni/Pd/Au metallization.
9. A package, comprising:
a heat sink made of a copper alloy having a thermal conductivity of at least 350 W/mK;
a die attached to a surface of the heat sink;
a ceramic window frame having a bottom surface attached to a periphery of the heat sink surface via a cured epoxy, the ceramic window frame generally surrounding the die; and
a fillet formed from a portion of the cured epoxy disposed along an outer sidewall of the ceramic window frame facing away from the die, the fillet extending over at least 25% of the height of the outer sidewall of the ceramic window frame as measured from the heat sink surface.
10. The package of claim 9 , wherein the cured epoxy has a cure temperature above 125° C., but less than about 265° C.
11. The package of claim 10 , wherein the cured epoxy has a cure temperature above 200° C., but less than about 265° C.
12. The package of claim 9 , wherein the heat sink is plated with a Ni/Pd/Au metallization.
13. The package of claim 9 , further comprising an additional fillet formed from a portion of the cured epoxy disposed along an inner sidewall of the ceramic window frame facing toward the die.
14. The package of claim 9 , wherein the fillet extends up to about 50% of the height of the outer sidewall of the ceramic window frame.
15. The package of claim 9 , wherein the ceramic window frame comprises 95% alumina.