Package on-package structures and methods for forming the same
A package includes a package component, which further includes a top surface and a metal pad at the top surface of the package component. The package further includes a non-reflowable electrical connector over and bonded to the metal pad, and a molding material over the package component. The non-reflowable electrical connector is molded in the molding material and in contact with the molding material. The non-reflowable electrical connector has a top surface lower than a top surface of the molding compound.
1. A package comprising:
a bottom package comprising:
a first package component comprising:
a top surface; and
a metal pad at the top surface of the first package component;
a non-reflowable electrical connector over and bonded to the metal pad, wherein a top surface of the non-reflowable electrical connector comprises a rounded portion, with a center portion of the rounded portion being lower than surrounding portions of the rounded portion; and
a molding material over the first package component, with the non-reflowable electrical connector partially molded in the molding material and in contact with the molding material;
a top package over the bottom package; and
a solder region bonding the non-reflowable electrical connector to the top package, wherein the solder region and the non-reflowable electrical connector comprise different materials.
2. The package of claim 1 , wherein the non-reflowable electrical connector has a rounded bottom surface, with the bottom surface having a shape of a part of a ball.
3. The package of claim 2 further comprising a solder paste disposed between, and in contact with, the rounded bottom surface of the non-reflowable electrical connector and a top surface of the metal pad.
4. The package of claim 1 , wherein the non-reflowable electrical connector is in physical contact with the solder region.
5. The package of claim 1 , wherein the non-reflowable electrical connector comprises copper.
6. The package of claim 1 further comprising a second package component bonded to the top surface of the first package component, wherein the molding material molds at least a lower part of the second package component therein.
7. A package comprising:
a bottom package comprising:
a package substrate comprising:
a top surface; and
a metal pad at the top surface of the package substrate;
a partial metal ball over and bonded to the metal pad, wherein the partial metal ball is formed of a non-reflowable material, and a bottom surface of the partial metal ball has a shape of a bottom surface of a ball, wherein the partial metal ball has a top surface;
a die over and bonded to the package substrate; and
a molding material over the package substrate, wherein the partial metal ball and a lower portion of the die are molded in the molding material, and a center portion of the top surface of the partial metal ball is lower than a top surface of the molding material;
a top package over the bottom package; and
an electrical connector bonding the partial metal ball to the top package.
8. The package of claim 7 , wherein the partial metal ball has a non-planar top surface.
9. The package of claim 8 , wherein the top surface of the partial metal ball comprises a rounded portion, with lowest point of the rounded portion being close to a center of the top surface of the partial metal ball.
10. The package of claim 7 further comprising a solder paste disposed between, and in contact with, a rounded bottom surface of the partial metal ball and a top surface of the metal pad.
11. The package of claim 7 , wherein the partial metal ball and the electrical connector comprise copper.
12. The package of claim 7 , wherein the partial metal ball comprises solder.
13. The package of claim 1 , wherein the center portion of the rounded portion is a lowest portion of the top surface of the non-reflowable electrical connector.
14. A package comprising:
a bottom package comprising:
a package substrate comprising:
a top surface; and
a metal pad at the top surface of the package substrate;
a partial metal ball over and bonded to the metal pad, wherein the partial metal ball is formed of a non-reflowable material, and a bottom surface of the partial metal ball has a shape of a bottom surface of a ball, and wherein a top surface of the partial metal ball comprises a rounded portion, with the lowest point of the rounded portion being close to a center of the top surface of the partial metal ball;
a die over and bonded to the package substrate; and
a molding material over the package substrate, wherein the partial metal ball and a lower portion of the die are molded in the molding material;
a top package over the bottom package; and
an electrical connector bonding the partial metal ball to the top package.
15. The package of claim 14 , wherein a center portion of the top surface of the partial metal ball is lower than a top surface of the molding material.
16. The package of claim 14 , wherein the partial metal ball has a non-planar top surface.
17. The package of claim 16 , wherein the partial metal ball comprises copper.
18. The package of claim 14 further comprising a solder paste disposed between, and in contact with, a rounded bottom surface of the partial metal ball and a top surface of the metal pad.
19. The package of claim 14 , wherein the partial metal ball and the electrical connector comprise copper.
20. The package of claim 14 , wherein the partial metal ball comprises solder.