Package structures and method for forming the same

A package structure, comprising:

• a first package component mounted on a substrate;
• a lid structure disposed on the first package component and around the first package component, wherein the lid structure has a plurality of sections separated from each other, and each of the sections of the lid structure partially covers the first package component and exposes a top surface of an underfill of the first package component, wherein the sections of the lid structure are free from direct contact with the underfill;
• and
• a thermal interface material located between the first package component and the lid structure, wherein the thermal interface material has a plurality of sections, and the plurality of sections are separated from each other without overlapping a top surface of the underfill.

A method for forming a package structure, comprising:

• providing a substrate;
• mounting a first package component to the substrate, wherein the first package component comprises a plurality of integrated circuit dies and an underfill formed between the integrated circuit dies;
• disposing a thermal interface material on the first package component, wherein the thermal interface material covers the integrated circuit dies and has an opening exposing the underfill in a normal direction of the substrate;
• and
• disposing a lid structure on the substrate and around the first package component, wherein the lid structure covers the integrated circuit dies and exposes the underfill in the normal direction of the substrate, a top surface of the underfill is lower than a top surface of the lid structure, and a bottom surface of the underfill is higher than a bottom surface of the lid structure.