Package structure including a package lid having a plurality of fins and methods of forming the same

A method of forming a package structure, comprising:

• forming a package lid comprising a package lid foot portion, a package lid plate portion connected to the package lid foot portion, and a plurality of fins extending from the package lid plate portion;
• attaching an interposer module to a package substrate, wherein the interposer module comprises a backside metal (BSM) layer;
• placing a thermal interface material (TIM) layer on the BSM layer of the interposer module;
• and
• attaching the package lid to the package substrate such that the plurality of fins of the package lid plate portion extend into the TIM layer over the interposer module.

A package structure, comprising:

• a package substrate;
• an interposer module including a plurality of semiconductor dies on the package substrate;
• a metallic thermal interface material (TIM) layer on the interposer module;
• and
• a package lid on the metallic TIM layer, comprising:
• a package lid foot portion attached to the package substrate;
• a package lid plate portion over the interposer module and connected to the package lid foot portion;
• a plurality of fins extending from the package lid plate portion into the metallic TIM layer over the plurality of semiconductor dies of the interposer module, wherein the plurality of fins comprises a circular cylindrical shape and an arc-shaped end portion of the plurality of fins is embedded in the metallic TIM layer;
• and
• a plating layer on the plurality of fins and on a bottom surface of the package lid plate portion, wherein the plating layer contacts an upper surface of the metallic TIM layer.