Method of making exposed pad ball grid array package
View Patent ↗A method of making an exposed-pad ball-grid array package ( 11 ) includes applying a conductive sheet ( 16 ) to an adhesive tape ( 18 ). Stamping the conductive sheet ( 16 ) to form a die pad ( 24 ) and separating the remainder ( 26 ) of the sheet from the adhesive tape ( 18 ) so that only the die pad ( 24 ) remains on the adhesive tape ( 18 ). A substrate ( 28 ) is applied to the adhesive tape ( 18 ) proximate to the die pad ( 24 ). A die ( 30 ) is attached to the die pad ( 24 ) and electrically coupled to the substrate ( 28 ). An encapsulant ( 34 ) is formed around at least a portion of the die ( 30 ), the die pad ( 24 ) and the substrate ( 28 ) above the adhesive tape ( 18 ). The adhesive tape ( 18 ) is removed from the die pad ( 24 ), substrate ( 28 ) and encapsulant ( 34 ). Conductive balls ( 36 ) are attached to the substrate ( 28 ).
1. A method of making an exposed-pad ball-grid array (BGA) package comprising:
applying a conductive sheet to an adhesive tape;
forming a die pad from the conductive sheet by stamping a portion of the conductive sheet and removing a remainder of the conductive sheet, wherein the stamped portion of the conductive sheet defines the die pad;
applying a substrate to the adhesive tape proximate to the die pad;
attaching a semiconductor die to the die pad;
electrically coupling the die to a top surface of the substrate;
encapsulating at least a portion of the die, the die pad and the substrate with an encapsulant above the adhesive tape;
removing the adhesive tape from the die pad, substrate and encapsulant; and
attaching at least one conductive ball to a bottom surface of the substrate.
2. The method of making an exposed-pad BGA package according to claim 1 , further comprising:
forming a plurality of die pads in the stamping step;
attaching a semiconductor die to each of the plurality of die pads; and
dividing the substrate in order to form a plurality of BGA packages each having at least one die and die pad.
3. The method of making an exposed-pad BGA package according to claim 2 , further comprising removing at least a portion of the encapsulant from an upper surface of the substrate.
4. The method of making an exposed-pad BGA package according to claim 3 , further comprising stacking the exposed-pad BGA package on another exposed-pad BGA package so that the at least one conductive ball of the exposed-pad BGA package electrically contacts conductive traces of the substrate of the other exposed-pad BGA package.
5. The method of making an exposed-pad BGA package according to claim 2 , wherein the conductive sheet and the adhesive tape are fed from one of a roll of material, a stack of sheets of material, a film-stretcher and an extruder.
6. The method of making an exposed-pad BGA package according to claim 2 , wherein the dividing is performed by one of sawing, punching and slicing.
7. The method of making an exposed-pad BGA package according to claim 1 , further comprising electrically coupling the die pad to a printed circuit board.
8. The method of making an exposed-pad BGA package according to claim 7 , wherein the electrical coupling of the die pad to the printed circuit board includes soldering.
9. The method of making an exposed-pad BGA package according to claim 1 , wherein the conductive sheet is one of copper foil, nickel-plated copper foil, palladium-plated copper foil and nickel-palladium-plated copper foil.
10. The method of making an exposed-pad BGA package according to claim 1 , wherein adhesive tape is polyimide adhesive tape.
11. The method of making an exposed-pad BGA package according to claim 1 , wherein the removal of the adhesive tape leaves an underside of the die pad exposed.
12. The method of making an exposed-pad BGA package according to claim 1 , wherein the die stamping step includes using a plurality of die stamps to simultaneously form a plurality of die pads during stamping.
13. The method of making an exposed-pad BGA package according to claim 12 , wherein various size die stamps are used to form die pads of varying size.
14. An exposed-pad ball-grid array (BGA) package formed in accordance with the method of claim 1 .
15. A method of making an exposed-pad ball-grid array (BGA) package comprising:
laminating a foil sheet to an adhesive tape;
forming at least one die pad on the adhesive tape by stamping the laminated foil sheet;
applying a substrate to the adhesive tape proximate to the die pad;
attaching a semiconductor die to the die pad;
electrically coupling the die to the substrate;
encapsulating at least a portion of the die, the die pad and the substrate with an encapsulant above the adhesive tape;
removing the adhesive tape from the die pad, substrate and encapsulant; and
attaching at least one conductive ball to a bottom surface of the substrate.
16. The method of making an exposed-pad BGA package according to claim 15 , wherein the conductive sheet is one of copper foil, nickel-plated copper foil, palladium-plated copper foil and nickel-palladium-plated copper foil.
17. The method of making an exposed-pad BGA package according to claim 16 , wherein adhesive tape is polyimide adhesive tape.
18. The method of making an exposed-pad BGA package according to claim 15 , wherein various size die pads are formed by the stamping step.
19. The method of making an exposed-pad BGA package according to claim 15 , wherein the electrically coupling step comprises wirebonding.
20. The method of making an exposed-pad BGA package according to claim 15 , further comprising:
forming a plurality of die pads in the stamping step;
attaching a semiconductor die to each of the plurality of die pads; and
singulating the substrate in order to form a plurality of BGA packages each having at least one die and die pad.