Package substrate having photo-sensitive dielectric layer and method of fabricating the same

摘要

A package substrate and a method of fabricating the package substrate are provided. The package substrate may include an interposer having at least one conductive through via, a photo-sensitive dielectric layer formed on one side of the interposer, and at least one conductive via formed in the photo-sensitive dielectric layer and electrically connected to the conductive through via. By means of a photo lithography process with high alignment accuracy, at least one via with an extremely small diameter can be formed on the photo-sensitive dielectric layer and align with the conductive through via. Therefore, the conductive through via can have its diameter reduced as required, without considering the alignment with the at least one via. Accordingly, the interconnection density of the conductive through via on the interposer is increased.

主权项

1. A package substrate, comprising:
an interposer having a first side and a second side opposite to the first side; at least one conductive through via penetrating from the first side to the second side; a redistribution layer formed on the first side and electrically connected to the conductive through via; a photo-sensitive dielectric layer formed on the second side of the interposer; a molding layer formed to encapsulate the interposer, wherein a bottom surface of the molding layer is aligned with an end of the conductive through via, and the photo-sensitive dielectric layer directly covers the molding layer and the interposer; and at least one conductive via formed in the photo-sensitive dielectric layer and electrically connected to the conductive through via, wherein the conductive via is in direct physical and electrical contact with the conductive through via, wherein the photo-sensitive dielectric layer is photo-sensitive polyimide (PSPI).