Conformal dummy die

1. A packaged semiconductor device comprising:

a semiconductor die having a plurality of pads on an active side;

a dummy die having a plurality of openings that extend from a first major surface to a second major surface opposite the first major surface, wherein the plurality of openings are aligned with the plurality of pads;

a silicone-based glue attaching the dummy die to the active side of the semiconductor die, wherein a plurality of bondable surfaces of the semiconductor die are exposed through the plurality of openings of the dummy die;

an under bump metallization (UBM) layer formed on the plurality of pads, wherein top surfaces of the UBM layer on the plurality of pads provide the plurality of bondable surfaces;

a plurality of solder bumps attached to the UBM layer on the plurality of pads, and

a fillet of the silicone-based glue laterally surrounding and contacting each solder bump, wherein the fillet provides a sealed barrier over the active surface of the semiconductor die within each opening of the dummy die.

2. The packaged semiconductor device of claim 1 , wherein

each opening of the dummy die is aligned to a respective pad of the semiconductor die, and

a portion of the dummy die is located between adjacent pads.

3. The packaged semiconductor device of claim 1 , wherein

the dummy die has a perimeter that corresponds to a perimeter of the semiconductor die.

4. The packaged semiconductor device of claim 1 , wherein

the semiconductor die includes a stress-sensitive area on the active side, wherein the dummy die covers the stress-sensitive area.

5. The packaged semiconductor device of claim 4 , wherein

the dummy die has a perimeter that extends beyond a perimeter of the stress-sensitive area by a minimum distance.

6. The packaged semiconductor device of claim 4 , wherein

the stress-sensitive area extends underneath at least one of the plurality of pads on the semiconductor die.

7. The packaged semiconductor device of claim 1 , wherein

the dummy die has a thickness in a range between 10 and 100 microns.

8. The packaged semiconductor device of claim 1 , wherein

the silicone-based glue has a thickness in a range between 20 and 50 microns.

9. The packaged semiconductor device of claim 1 , wherein

a portion of the plurality of openings are located in a peripheral part of the dummy die.

10. The packaged semiconductor device of claim 1 , wherein

a portion of the plurality of openings are located in a central part of the dummy die.

11. The packaged semiconductor device of claim 1 , wherein

the semiconductor die is one of a plurality of semiconductor dies as part of a semiconductor die wafer,

the dummy die is one of a plurality of dummy dies as part of a dummy die wafer, and

the silicone-based glue attaches the dummy die wafer to the semiconductor die wafer, wherein the plurality of bondable surfaces of each of the plurality of semiconductor dies are exposed through the plurality of openings of each of the plurality of dummy dies.

12. A packaged semiconductor device comprising:

a semiconductor die having a plurality of pads on an active side;

a dummy die having a plurality of openings that extend from a first major surface to a second major surface opposite the first major surface, wherein the plurality of openings are aligned with the plurality of pads; and

a silicone-based glue attaching the dummy die to the active side of the semiconductor die, wherein a plurality of bondable surfaces of the semiconductor die are exposed through the plurality of openings of the dummy die;

a plurality of stud bumps formed on the plurality of pads, wherein top surfaces of the plurality of stud bumps provide the plurality of bondable surfaces; and

a fillet of the silicone-based glue laterally surrounding and contacting each stud bump, wherein the fillet provides a sealed barrier over the active surface of the semiconductor die within each opening of the dummy die.

13. A packaged semiconductor device comprising:

a semiconductor die having a plurality of pads on an active side;

a dummy die having a plurality of openings that extend from a first major surface to a second major surface opposite the first major surface, wherein the plurality of openings are aligned with the plurality of pads; and

a silicone-based glue attaching the dummy die to the active side of the semiconductor die, wherein a plurality of bondable surfaces of the semiconductor die are exposed through the plurality of openings of the dummy die;

a plurality of ball bonds attached to the plurality of bondable surfaces within each opening of the dummy die; and

a fillet of the silicone-based glue laterally surrounding and contacting each ball bond, wherein the fillet provides a sealed barrier over the active surface of the semiconductor die within each opening of the dummy die.

14. A packaged semiconductor device comprising:

a semiconductor die having a plurality of pads on an active side;

a dummy die having a plurality of openings that extend from a first major surface to a second major surface opposite the first major surface, wherein the plurality of openings are aligned with the plurality of pads; and

a silicone-based glue attaching the dummy die to the active side of the semiconductor die, wherein a plurality of bondable surfaces of the semiconductor die are exposed through the plurality of openings of the dummy die;

a plurality of ball bonds attached to the plurality of bondable surfaces within each opening of the dummy die; and

a lead frame having a die flag and a plurality of lead fingers, wherein

a back side of the semiconductor die is attached to the die flag with die attach material, and

the plurality of ball bonds are part of a plurality of wire bond interconnects that also include tail bonds attached to the plurality of lead fingers.

15. The packaged semiconductor device of claim 14 , further comprising:

an encapsulant body that encapsulates the lead frame, the semiconductor die, the dummy die, and the plurality of wire bond interconnects.