Package with UBM and Methods of Forming

A package structure comprising:

• a composite structure comprising an integrated circuit die and an encapsulating material at least laterally encapsulating the integrated circuit die;
• a redistribution structure on the composite structure, a first surface of the redistribution structure being distal from the composite structure;
• an under ball metallization (UBM) on the redistribution structure, the UBM having a first portion on the first surface, a sidewall of the first portion forming a non-perpendicular angle with the first surface, the non-perpendicular angle being measured internal to the UBM;
• an adhesion layer on the first portion of the UBM;
• a first dielectric layer on the redistribution structure and adjoining the adhesion layer;
• and
• an external electrical connector disposed through the first dielectric layer and on the UBM.

A method comprising:

• encapsulating an integrated circuit die with an encapsulant;
• forming a redistribution structure on the integrated circuit die and the encapsulant, the redistribution structure comprising a metallization pattern and a first dielectric layer on the metallization pattern, the first dielectric layer having a first surface distal from the integrated circuit die and the encapsulant;
• forming an under ball metallization (UBM) on the redistribution structure, the UBM having a first portion on the first surface and a second portion disposed in an opening through the first dielectric layer to the metallization pattern, the first portion of the UBM having a sidewall surface that is non-perpendicular to the first surface of the first dielectric layer;
• forming a second dielectric layer on the first surface of the first dielectric layer and the first portion of the UBM;
• and
• forming an external electrical connector through an opening through the second dielectric layer to the UBM.