Encapsulation of a stack of semiconductor dice
Systems and methods for encapsulating a stack of semiconductor dice are described. A stack of semiconductor dice may be formed, for example by attaching die to flexible printed circuit supports attached to frames and stacking the supports, and then encapsulated by flowing a liquid encapsulant around the stack of dice and solidifying the liquid encapsulant. The die supports may contain encapsulant flow openings, such as rectangular slits, that allow the liquid encapsulant to flow around the stack of dice.
1. A method comprising:
forming a stack of semiconductor dice; and
encapsulating the stack of semiconductor dice by flowing a liquid encapsulant through a plurality of encapsulant flow openings in a printed circuit support, where the openings are proximate to, and on all four sides of, a position of attachment of a die to the printed circuit support, and by solidifying the liquid encapsulant in the openings.
2. The method of claim 1 , wherein said flowing the encapsulant through the openings comprises flowing the encapsulant through an encapsulant flow opening having a rectangular, square, circular, or triangular shape.
3. The method of claim 1 , wherein said flowing the encapsulant through the openings comprises flowing the encapsulant through a slit.
4. The method of claim 1 , wherein said flowing the encapsulant through the openings comprises flowing the encapsulant from one side of the printed circuit support to another.
5. The method of claim 1 , wherein said forming the stack of semiconductor dice comprises attaching dice to the printed circuit support based at least in part on die defect information.
6. The method of claim 1 , wherein said forming the stack of semiconductor dice comprises forming a stack of semiconductor dice that includes Flash memory, and further comprising including the encapsulated stack of semiconductor dice in a mobile communication system.
7. A method comprising:
attaching a die to a flexible printed circuit that is held in a rigid frame, the flexible printed circuit including an encapsulant flow opening;
stacking a second die relative to the die to create a stack of semiconductor dice; and
encapsulating the stack of the semiconductor dice by flowing an encapsulant through the encapsulant flow opening, and solidifying the encapsulant in the opening.
8. The method of claim 7 , wherein said flowing the encapsulant through the opening comprises flowing the encapsulant through a slit having a width between 0.5–2millimeters and a length that is greater than 2 millimeters.
9. The method of claim 7 , further comprising flowing the encapsulant through a first plurality of encapsulant flow openings in the flexible printed circuit that are each proximate a first die attach position and flowing the encapsulant through a second plurality of encapsulant flow openings that are each proximate a second die attach position.
10. The method of claim 7 , wherein the die and the second die have bare semiconductor surfaces during said stacking.
11. The method of claim 7 , wherein the second die is stacked relative to the die based at least in part on die defect information and die attach position defect information.
12. The method of claim 7 , further comprising:
placing the stack of semiconductor dice in an encapsulation chamber,
adding liquid encapsulant to the chamber; and
flowing the liquid encapsulant from the encapsulation chamber through the encapsulant flow opening.
13. The method of claim 7 , wherein flowing the encapsulant through the opening comprises flowing the encapsulant through an opening having a shape selected from a rectangular, square, circular, or triangular shape.
14. The method of claim 7 , wherein said attaching the die to the flexible printed circuit comprises attaching a die having Flash memory, and further comprising including the encapsulated stack of semiconductor dice in a mobile communication system.
15. A method comprising:
forming a stack of semiconductor dice; and
encapsulating the stack of semiconductor dice by flowing a liquid encapsulant through a plurality of encapsulant flow openings through a printed circuit support, and solidifying the liquid encapsulant in the openings, where the openings are proximate a die attach position of the printed circuit support and are on opposite sides of the die attach position, and wherein the openings include a slit.
16. The method of claim 15 , further comprising forming an encapsulant flow opening of the plurality in the printed circuit support by an approach selected from punching, puncturing, cutting, and drilling.
17. The method of claim 15 , wherein said forming the stack comprises forming a stack that includes a Flash memory, and further comprising including the encapsulated stack of semiconductor dice in a cellular phone.
18. A method comprising:
forming a stack of semiconductor dice; and
encapsulating the stack of semiconductor dice by flowing an encapsulant through encapsulant flow openings in a printed circuit support, and solidifying the encapsulant in the openings, where the openings are proximate a die attach position of the printed circuit support, are on opposite sides of the die attach position, and are on all four sides of the die attach position.
19. The method of claim 18 , further comprising forming an encapsulant flow opening of the plurality in the printed circuit support by an approach selected from punching, puncturing, cutting, and drilling.
20. The method of claim 18 , wherein said forming the stack comprises forming a stack that includes a Flash memory, and further comprising including the encapsulated stack of semiconductor dice in a cellular phone.
21. A method comprising:
attaching a first die to a first printed circuit having a first encapsulant flow opening;
attaching a second die to a second printed circuit having a second encapsulant flow opening;
stacking the first die attached to the first printed circuit over the second die attached to the second printed circuit;
after said stacking, flowing an encapsulant through the first encapsulant flow opening from one side of the first printed circuit to another, flowing the encapsulant through the second encapsulant flow opening from one side of the second printed circuit to another; and
solidifying the encapsulant over and around the first die and the second die and in the first and second encapsulant flow openings.
22. The method of claim 21 , wherein said flowing the encapsulant through the first encapsulant flow opening comprises flowing the encapsulant through an opening having a rectangular, square, circular, or triangular shape.
23. The method of claim 21 , wherein said attaching the first die to the first printed circuit comprises attaching the first die to a printed circuit held in a rigid frame.
24. The method of claim 23 , further comprising aligning the first and the second die by using alignment holes of the frames.
25. The method of claim 21 , wherein said attaching the first die and the second die comprises attaching the dice based, at least in part, on die defect information.
26. The method of claim 21 , wherein said attaching the first die comprises attaching the first die to the first printed circuit between a plurality of encapsulant flow openings of the first printed circuit.
27. The method of claim 21 , wherein the first die comprises Flash memory, and further comprising placing the encapsulated stack in a mobile communication system.