Semiconductor packages and methods of forming

A semiconductor package comprising:

• a substrate;
• a first encapsulant material on the substrate;
• a semiconductor structure embedded in the first encapsulant material, wherein the semiconductor structure comprises:
• an interposer;
• a die attached to a first side of the interposer distal from the substrate;
• a second encapsulant material on the first side of the interposer around the die;
• and
• conductive bumps at a second side of the interposer facing the substrate;
• a thermal interface material (TIM) over a first side of the semiconductor structure distal from the substrate, wherein the first side of the semiconductor structure is exposed by the first encapsulant material;
• and
• a heat spreader over and attached to the TIM, wherein a lower surface of the heat spreader facing the semiconductor structure has a recess proximate to a sidewall of the TIM.

A method of forming a semiconductor package, the method comprising:

• attaching a semiconductor structure to a substrate;
• forming a first encapsulant material on the substrate around the semiconductor structure;
• after forming the first encapsulant material, forming a cavity in the first encapsulant material by removing a portion of the first encapsulant material, wherein a first surface of the semiconductor structure distal from the substrate is exposed at a bottom of the cavity, wherein a width of the cavity is larger than a width of the semiconductor structure;
• forming a thermal interface material (TIM) over the first surface of the semiconductor structure;
• and
• attaching a heat spreader to the TIM.