Structure and formation method of chip package with reinforcing structures

1. A method for forming a package structure, comprising:

disposing a die package and a reinforcing structure over a circuit substrate, wherein the reinforcing structure partially surrounds a corner of the die package, the die package has a first sidewall and a second sidewall opposite to the first sidewall, and the reinforcing structure has an end located between extension lines of the first sidewall and the second sidewall; and

forming an underfill structure over the circuit substrate after the reinforcing structure is disposed, wherein a first portion of the underfill structure is between the die package and the circuit substrate, a second portion of the underfill structure laterally extends exceeding an inner sidewall of the reinforcing structure, and the second portion of the underfill structure extends along and wraps around the end of the reinforcing structure, wherein in a top view of the package structure, the reinforcing structure has an outer corner, a first part of the second portion of the second portion of the underfill structure is between the outer corner of the reinforcing structure and the die package, and the outer corner of the reinforcing structure is exposed by the underfill structure.

2. The method for forming a package structure as claimed in claim 1 , further comprising disposing a warpage-control element over the circuit substrate after the underfill structure is formed, wherein the warpage-control element surrounds the die package and the reinforcing structure.

3. The method for forming a package structure as claimed in claim 1 , further comprising attaching the reinforcing structure to the circuit substrate through an adhesive layer, wherein the adhesive layer is in direct contact with the underfill structure.

4. The method for forming a package structure as claimed in claim 1 , further comprising disposing a second reinforcing structure to partially surround a second corner of the die package before the underfill structure is formed.

5. The method for forming a package structure as claimed in claim 1 , further comprising:

partially removing the circuit substrate to form a recess before the die package is disposed over the circuit substrate, wherein an element of the die package enters the recess after the die package is disposed over the circuit substrate.

6. The method for forming a package structure as claimed in claim 5 , wherein the underfill structure fills the recess and surrounds the element of the die package.

7. The method for forming a package structure as claimed in claim 5 , wherein the element of the die package is a chip structure.

8. The method for forming a package structure as claimed in claim 1 , wherein the underfill structure has a third portion adjacent to a sidewall of the die package, and the first part of the second portion is thicker than the third portion.

9. The method for forming a package structure as claimed in claim 8 , wherein the reinforcing structure has an outer sidewall, the inner sidewall is between the outer sidewall and the die package, and the inner sidewall is completely covered by the underfill structure.

10. The method for forming a package structure as claimed in claim 9 , wherein the outer sidewall of the reinforcing structure is partially covered by the underfill structure.

11. The method for forming a package structure as claimed in claim 10 , wherein the second portion of the underfill structure has a second part adjacent to the outer sidewall of the reinforcing structure, and the third portion of the underfill structure is thicker than the second part of the second portion.

12. The method for forming a package structure as claimed in claim 1 , further comprising:

disposing a second reinforcing structure over the circuit substrate, wherein the second reinforcing structure partially surrounds a second corner of the die package, and the second reinforcing structure is separated from the reinforcing structure.

13. A method for forming a package structure, comprising:

disposing a die package over a substrate;

disposing a reinforcing structure over the substrate, wherein the reinforcing structure partially surrounds a corner of the die package, and the reinforcing structure has an L-shape top view profile or a C-shape top view profile; and

forming an underfill structure over the substrate, wherein a first portion of the underfill structure is between the die package and the substrate, a second portion of the underfill structure laterally extends across opposite sidewalls of the reinforcing structure, and the underfill structure wraps around an end of the reinforcing structure, wherein in a top view of the package structure, the reinforcing structure has an outer corner, a part of the second portion of the second portion of the underfill structure is between the outer corner of the reinforcing structure and the die package, and the underfill structure is not in direct contact with the outer corner of the reinforcing structure.

14. The method for forming a package structure as claimed in claim 13 , further comprising:

disposing a second reinforcing structure over the substrate, wherein the second reinforcing structure partially surrounds a second corner of the die package, the second reinforcing structure has an end, and the die package extends across the end.

15. The method for forming a package structure as claimed in claim 14 , further comprising:

disposing a warpage-control element over the substrate after the underfill structure is formed, wherein the warpage-control element surrounds the die package, the reinforcing structure, and the second reinforcing structure.

16. The method for forming a package structure as claimed in claim 13 , wherein a top of the part of the second portion of the underfill structure is substantially as high as a top surface of the reinforcing structure.

17. A method for forming a package structure, comprising:

bonding a die package to a substrate through bonding structures, wherein the die package has a plurality of corners;

disposing a plurality of reinforcing structures over the substrate, wherein each of the corners of the die package is partially surrounded by at least one of the reinforcing structures, a reinforcing structure of the reinforcing structures has a portion extending across a corner of the corners, the portion has an end, and the die package extends across the end; and

forming an underfill structure surrounding the bonding structures, wherein the underfill structure partially surrounds the reinforcing structures and extends along and wraps around the end of the portion of the reinforcing structure, wherein in a top view of the package structure, the reinforcing structure of the reinforcing structures has an outer corner, a first portion of the underfill structure is between the outer corner of the reinforcing structure and the die package, and the outer corner of the reinforcing structure is separated from the underfill structure.

18. The method for forming a package structure as claimed in claim 17 , wherein the underfill structure is formed to have a second portion and a third portion, the second portion is adjacent to the die package and an interior sidewall of a second reinforcing structure of the reinforcing structures, the third portion is adjacent to a sidewall of the die package and separated from the second reinforcing structure, and the second portion is thicker than the third portion.

19. The method for forming a package structure as claimed in claim 17 , wherein top surfaces of the reinforcing structures are lower than a top surface of the die package.

20. The method for forming a package structure as claimed in claim 17 , wherein the underfill structure is formed to be in direct contact with the reinforcing structures.