Underfill pattern with gap

摘要

An embodiment is a structure comprising a package, a substrate, and external electrical connectors mechanically and electrically coupling the package to the substrate. The package contains a die. The external electrical connectors are between the package and the substrate. An underfill material is around a periphery region of the package and between the periphery region and the substrate. A gap is between a central region of the package and the substrate, and does not contain the underfill material. The underfill material may seal the gap. The gap may be an air gap. In some embodiments, the underfill material may fill greater than or equal to 10 percent and no more than 70 percent of a volume between the package and the substrate.

主权项

1. A structure comprising:
a first package comprising:
a first die comprising:
a passivation layer on an active side of the first die;a conductive pillar electrically connected to a conductive pad in the passivation layer; anda dielectric layer disposed around the conductive pillar;an encapsulant at least laterally encapsulating the first die; anda redistribution structure on an active side of the first die and the encapsulant, wherein the redistribution structure extends laterally past edges of the first die, and wherein an conductive feature in the redistribution structure is electrically connected to the conductive pad through the conductive pillar; a substrate; first external electrical connectors mechanically and electrically coupling the first package to the substrate, the first external electrical connectors being between the first package and the substrate; and an underfill material around a first periphery region of the first package and between the first periphery region and the substrate, a first gap being between a first central region of the first package and the substrate and not containing the underfill material, wherein a sidewall of the underfill material is disposed between a first one of the first external electrical connectors and a second one of the first external electrical connectors disposed within the first gap, wherein the underfill material extends along sidewalls of the redistribution structure, and wherein the underfill material extends higher than a surface of the passivation layer opposite the dielectric layer and lower than a surface of the first die opposite the redistribution structure.