Method of forming land grid array packaged device
View Patent ↗A method of packaging an integrated circuit die ( 12 ) includes the steps of forming an array of soft conductive balls ( 14 ) in a fixture ( 30 ) and flattening opposing sides of the balls. The flattened balls are then transferred from the fixture to a mold masking tape ( 36 ). A first side of the IC die is attached to the balls with a die attach adhesive ( 16 ) and then wire bonding pads ( 20 ) on the die are electrically connected directly to respective balls with wires ( 22 ). An encapsulant ( 24 ) is formed over the die, the electrical connections, and a top portion of the formed balls. The tape is removed and adjacent, encapsulated dice are separated via saw singulation. The result is an encapsulated IC having a bottom side with exposed balls.
1. A method of packaging an integrated circuit die, comprising the steps of:
forming a plurality of soft conductive forms in a fixture, wherein opposing sides of the forms are at least partially flattened;
transferring the formed forms from the fixture to a mold masking tape;
attaching a first side of an integrated circuit die to the mold masking tape, wherein a second side of the die has a plurality of die bonding pads and wherein the die is surrounded by the formed forms;
electrically connecting the die bonding pads to respective ones of the formed forms surrounding the die;
encapsulating the die, the electrical connections, and a top portion of the formed forms with a mold compound; and
removing the mold masking tape such that a bottom portions of the forms are exposed.
2. The method of packaging an integrated circuit die of claim 1 , wherein the forms formed in the fixture are spherical.
3. The method of packaging an integrated circuit die of claim 1 , wherein the forms formed in the fixture are generally rectangular.
4. The method of packaging an integrated circuit die of claim 1 , wherein the forms undergo a mechanical coining step wherein at least two opposing sides of the forms are at least partially flattened.
5. The method of packaging an integrated circuit die of claim 1 , wherein an array of forms is formed in the fixture.
6. The method of packaging an integrated circuit die of claim 1 , further comprising attaching the mold masking tape to a frame.
7. The method of packaging an integrated circuit die of claim 1 , wherein the die attaching step comprises attaching the first side of the die to a plurality of the forms with a die attach adhesive.
8. The method of packaging an integrated circuit die of claim 1 , wherein the electrically connecting step comprises wirebonding the die bonding pads to the respective ones of the forms with a corresponding plurality of wires.
9. The method of packaging an integrated circuit die of claim 8 , wherein in the wirebonding step, the wires penetrate into the forms and are embedded therein.
10. The method of packaging an integrated circuit die of claim 9 , wherein the wires are formed of copper, gold, or an alloy thereof.
11. The method of packaging an integrated circuit die of claim 10 , wherein the forms are formed of a metal that is softer than the wires so that the wires can be embedded into the forms.
12. The method of packaging an integrated circuit die of claim 11 , wherein the metal comprises solder or gold.
13. The method of packaging an integrated circuit die of claim 1 , further comprising the step of saw singulating the encapsulated die from adjacent encapsulated dice.
14. A method of packaging a plurality of integrated circuit dice, comprising the steps of:
forming a plurality of soft conductive forms in a fixture, wherein opposing sides of the forms are at least partially flattened;
transferring the formed forms from the fixture to a mold masking tape;
attaching first sides of the plurality of integrated circuit dice to the mold masking tape, wherein a second side of the dice have a plurality of die bonding pads and wherein each of the die is surrounded by some of the formed forms;
electrically connecting the die bonding pads of the dice to respective ones of the formed forms surrounding the dice;
encapsulating the dice, the electrical connections, and a top portion of the formed forms with a mold compound;
removing the mold masking tape such that a bottom portions of the forms are exposed; and
singulating the encapsulated dice to form individual packaged devices.
15. The method of packaging an integrated circuit die of claim 14 , wherein the forms formed in the fixture are spherical.
16. The method of packaging an integrated circuit die of claim 14 , wherein the forms formed in the fixture are generally rectangular.
17. The method of packaging an integrated circuit die of claim 14 , wherein the forms undergo a mechanical coining step wherein at least two opposing sides of the balls are at least partially flattened.
18. The method of packaging an integrated circuit die of claim 14 , wherein an array of forms is formed in the fixture.
19. The method of packaging an integrated circuit die of claim 14 , further comprising the step of attaching the mold masking tape to a frame.
20. The method of packaging an integrated circuit die of claim 14 , wherein the dice attaching step comprises attaching the first side of the dice to a plurality of the forms with a die attach adhesive.
21. The method of packaging an integrated circuit die of claim 14 , wherein the electrically connecting step comprises wirebonding the die bonding pads to the respective ones of the forms with a corresponding plurality of wires.
22. The method of packaging an integrated circuit die of claim 21 , wherein in the wirebonding step, the wires penetrate the forms and are embedded therein.
23. The method of packaging an integrated circuit die of claim 22 , wherein the wires are formed of copper, gold, or an alloy.
24. The method of packaging an integrated circuit die of claim 23 , wherein the forms are formed of a metal that is softer than the wires so that the wires can be embedded into the forms.
25. The method of packaging an integrated circuit die of claim 24 , wherein the metal comprises solder or gold.