Package structure, package-on-package structure and method of fabricating the same

A structure, comprising:

• a first redistribution layer, wherein the first redistribution layer comprises:
• a conductive layer embedded in a first dielectric layer;
• a plurality of connecting portions embedded in a second dielectric layer, wherein the second dielectric layer is directly disposed on the first dielectric layer, and the plurality of connecting portions is directly joined with a surface of the conductive layer, the plurality of connecting portions comprises joint patterns with two or more different shapes, including at least one circular joint pattern and at least one trapezoidal joint pattern that are exposed at a surface of the second dielectric layer, and a height of the plurality of connecting portions is greater than a thickness of the conductive layer;
• a semiconductor die disposed on the first dielectric layer;
• through insulator vias disposed on the first dielectric layer and electrically connected to the conductive layer;
• and
• a plurality of metallization layers electrically connected to the semiconductor die and the through insulator vias.

A package-on-package structure, comprising:

• a first package, the first package comprises:
• a plurality of connecting portions embedded in a first dielectric layer, wherein the plurality of connecting portions has a first side, a second side, and sidewalls joining the first side to the second side, the first side of the plurality of connecting portions is exposed from and coplanar with a first surface of the first dielectric layer;
• a conductive layer joined with the second side of the plurality of connecting portions;
• and
• a semiconductor die disposed over the first dielectric layer;
• a second package stacked on the first package, wherein the second package is electrically connected to the first side of the plurality of connecting portions through a plurality of conductive balls;
• an underfill disposed on the first dielectric layer and surrounding the plurality of conductive balls, wherein an interface between the underfill and the first dielectric layer is aligned with an interface between the plurality of conductive balls and the first side of the plurality of connecting portions;
• and
• a silver paste disposed on the first side of one of the connecting portions in between the first package and the second package, wherein the plurality of conductive balls of the second package surrounds the silver paste, and the underfill further surrounds and contact sidewalls of the silver paste.