Underfill Control Structures and Method

A package comprising:

• a semiconductor die encapsulated in a molding compound;
• a redistribution structure over the semiconductor die and the molding compound, wherein the redistribution structure comprises:
• a redistribution line;
• and
• a passivation layer covering a first portion of the redistribution line and exposing a second portion of the redistribution line;
• an external connector extending through the passivation layer to the first portion of the redistribution line;
• a surface device directly bonded to the second portion of the redistribution line;
• and
• an underfill between the redistribution structure and the surface device, wherein the underfill extends below a top surface of the passivation layer.

A package comprising:

• a die encapsulated in a molding compound:
• a redistribution line over and electrically connected to the die;
• a passivation layer partially covering the redistribution line;
• a passive device bonded to the redistribution line;
• and
• an underfill between the redistribution line and the passive device, wherein a sidewall of the passivation layer surrounds the underfill in a top down view.