Dummy die placement without backside chipping

1. A method comprising:

bonding a second package component to a first package component;

bonding a third package component to the first package component;

attaching a dummy die to the first package component;

encapsulating the second package component, the third package component, and the dummy die in an encapsulant;

performing a planarization process to level a top surface of the second package component with a top surface of the encapsulant, wherein after the planarization process, an upper portion of the encapsulant overlaps the dummy die; and

sawing-through the dummy die to separate the dummy die into a first dummy die portion and a second dummy die portion, wherein the upper portion of the encapsulant is sawed through.

2. The method of claim 1 , wherein the upper portion of the encapsulant has a thickness greater than about 5 μm.

3. The method of claim 1 , wherein the second package component and the third package component are spaced apart from each other by a space, and wherein the dummy die comprises:

a first portion in the space; and

second portions on opposite sides of the space.

4. The method of claim 1 , wherein at a time the dummy die is sawed through, an entirety of the dummy die is covered by the encapsulant.

5. The method of claim 1 , wherein at a time the dummy die is sawed through, the dummy die comprises a first top surface that is exposed, and a second top surface covered by the upper portion of the encapsulant.

6. The method of claim 5 , wherein after the sawing, in a plane view of the upper portion of the encapsulant, the upper portion of the encapsulant has a length and a width smaller than the length, and wherein the width is greater than about 50 μm.

7. The method of claim 1 , wherein the dummy die comprises silicon.

8. The method of claim 1 , wherein the planarization process is performed until the third package component is further revealed.

9. A method comprising:

bonding a first package component to a second package component, wherein the first package component comprises a device die;

attaching a dummy die to the second package component, wherein the dummy die comprises a recess;

encapsulating the first package component and the dummy die in an encapsulant, wherein the encapsulant comprises a portion filling the recess; and

performing a singulation process using a blade to form a package, wherein the package comprises the first package component, a portion of the second package component, and a portion of the dummy die, and wherein the blade cuts through the portion of the encapsulant in the recess.

10. The method of claim 9 , wherein the portion of the encapsulant in the recess is cut into two portions.

11. The method of claim 9 , wherein the recess is elongated with a lengthwise direction, and the blade cuts along the lengthwise direction.

12. The method of claim 9 further comprising, after the encapsulating and before the singulation process, performing a planarization process to expose a surface of the dummy die.

13. The method of claim 9 , wherein the portion of the encapsulant in the recess and cut through by the blade has a thickness in a range between about 5 μm and about 600 μm.

14. The method of claim 9 , wherein after the singulation process, the portion of the encapsulant in the recess has a remaining portion in the package, and the remaining portion of the encapsulant has a width in a range between about 60 μm and about 500 μm.

15. The method of claim 9 , wherein when the singulation process is performed, the first package component is exposed through the encapsulant.

16. A method comprising:

bonding a first package component to a second package component;

attaching a dummy die to the second package component;

molding the first package component and the dummy die in a molding compound; and

performing a die-saw process to form a package, wherein the package comprises the first package component, a first portion of the second package component, and a second portion of the dummy die, and wherein a saw line of the die-saw process passes through an additional portion of the molding compound and a portion of the dummy die that is directly underlying the additional portion of the molding compound.

17. The method of claim 16 , wherein the additional portion of the molding compound has a first top surface coplanar with a second top surface of the dummy die.

18. The method of claim 16 further comprising, before the molding, recessing the dummy die to form a recess, wherein the molding compound is filled into the recess.

19. The method of claim 18 further comprising:

after the molding and before the molding, performing a planarization process to level top surfaces of the molding compound and the dummy die, wherein the recessing is performed after the planarization process.

20. The method of claim 19 , wherein in the recessing, the first package component is un-recessed.