Wafer bonded top-side cooling module with thermal interface material containment

A microelectronic module comprising:

• a module substrate;
• at least one flip-chip die attached to a top surface of the module substrate;
• at least one heat spreader residing over and thermally coupled to the at least one flip-chip die;
• a mold compound formed over the top surface of the module substrate and surrounding the at least one flip-chip die and the at least one heat spreader, wherein:
• a top surface of the mold compound and a top surface of the at least one heat spreader are coplanar;
• and
• a plurality of heat spreader notches is formed at the top surface of the at least one heat spreader;
• a thermal interface material (TIM) section that fills each of the plurality of heat spreader notches and extends over the top surface of the at least one heat spreader and the top surface of the mold compound;
• and
• a heat sink directly residing on the TIM section and thermally coupled to the at least one heat spreader through the TIM section, wherein the plurality of heat spreader notches is configured to constrain certain portions of the TIM section confined within the top surface of the at least one heat spreader.

A microelectronic module comprising:

• a module substrate;
• at least one flip-chip die attached to a top surface of the module substrate;
• at least one heat spreader residing over and thermally coupled to the at least one flip-chip die;
• a mold compound formed over the top surface of the module substrate and surrounding the at least one flip-chip die and the at least one heat spreader, wherein:
• a top surface of the mold compound and a top surface of the at least one heat spreader are coplanar;
• and
• at least one mold compound notch is formed at the top surface of the mold compound and surrounding the at least one heat spreader;
• a thermal interface material (TIM) section that fills the at least one mold compound notch and extends over the top surface of the at least one heat spreader and the top surface of the mold compound;
• and
• a heat sink directly residing on the TIM section and thermally coupled to the at least one heat spreader through the TIM section, wherein the at least one mold compound notch is configured to constrain certain portions of the TIM section confined within the top surface of the at least one heat spreader.

A communication device comprising:

• a control system;
• a baseband processor;
• receive circuitry;
• and
• transmit circuitry, wherein at least one or any combination of the control system, the baseband processer, the transmit circuitry, and the receive circuitry is implemented in a microelectronic module, which has a module substrate, at least one flip-chip die, at least one heat spreader, a mold compound, at least one thermal interface material (TIM) section, at least one TIM barrier, and a heat sink, wherein:
• the at least one flip-chip die is attached to a top surface of the module substrate, and the at least one heat spreader resides over and is thermally coupled to the at least one flip-chip die;
• the mold compound is formed over the top surface of the module substrate and surrounds the at least one flip-chip die and the at least one heat spreader, wherein a top surface of the mold compound and a top surface of the at least one heat spreader are coplanar;
• the at least one TIM barrier continuously surrounds a periphery of the at least one heat spreader and protrudes vertically beyond the top surface of the at least one heat spreader to provide at least one TIM cavity;
• the at least one TIM section covers at least the top surface of the at least one heat spreader and fills the at least one TIM cavity;
• and
• the heat sink resides over and is thermally coupled to the at least one heat spreader through the at least one TIM section, wherein the heat
• sink is in contact with both the at least one TIM section and the at least one TIM barrier, and the TIM barrier is configured to prevent the at least one TIM section from shifting away from the top surface of the at least one heat spreader.

A method of fabricating a microelectronic package comprising:

• providing a precursor module, which includes a module substrate, at least one flip-chip die, at least one heat spreader, and a mold compound, wherein:
• the at least one flip-chip die is attached to a top surface of the module substrate, and the at least one heat spreader resides over and is thermally coupled to the at least one flip-chip die;
• and
• the mold compound is formed over the top surface of the module substrate and surrounds the at least one flip-chip die and the at least one heat spreader, wherein a top surface of the mold compound and a top surface of the at least one heat spreader are coplanar;
• forming at least one ring trench within the mold compound and continuously surrounding the at least one heat spreader, wherein the at least one ring trench extends vertically from the top surface of the mold compound and downwardly into the mold compound;
• applying an adhesive material to fill the at least one ring trench and protrude the top surface of the at least one heat spreader, so as to form at least one thermal interface material (TIM) barrier continuously surrounding the at least one heat spreader, wherein the protrusion of the at least one TIM barrier provides at least one TIM cavity over the top surface of the at least one heat spreader;
• applying a TIM over the top surface of the at least one heat spreader and fully filling the at least one TIM cavity to form at least one TIM section;
• and
• placing a heat sink in contact with the at least one TIM section and the at least one TIM barrier, wherein the TIM barrier is configured to prevent the at least one TIM section from shifting away from the top surface of the at least one heat spreader, thereby maintaining thermal coupling between the heat sink and the at least one heat spreader through the at least one TIM section.