Semiconductor device and method of controlling distribution of liquid metal TIM using lid structure
A semiconductor device has an electrical component and a heat sink disposed over the electrical component. The heat sink has a cover with a wall extending from the cover forming a pocket around a perimeter of the electrical component. The heat sink also has a horizontal step, and a riser extending from the horizontal step to the cover. The wall extends from the cover to form the pocket. A TIM is disposed between the cover and a surface of the electrical component. The TIM can be liquid metal. The heat sink is pressed onto the TIM under force and heat to distribute the TIM between the cover and surface of the electrical component. The TIM remains contained within the pocket by the wall. The wall or cover can have a vent hole. The TIM may extend over a side surface of the electrical component.
1 . A semiconductor device, comprising:
a substrate;
an electrical component disposed over the substrate;
a dam material disposed on the substrate around the electrical component;
an underfill material filling a first gap between substrate and electrical component, wherein the underfill material extends to the dam material;
a heat sink disposed over the electrical component, wherein the heat sink includes a cover with a wall extending from the cover forming a pocket around a perimeter of the electrical component, wherein the pocket includes a lateral gap between the wall and the electrical component such that the electrical component does not directly physically contact the wall, and wherein the wall is a unibody extension of the cover; and
a thermal interface material (TIM) disposed between the cover and a surface of the electrical component, wherein the TIM remains contained within the pocket by physical contact with the wall, wherein the TIM is routed down a side surface of the electrical component physically contacting the side surface of the electrical component, and wherein the TIM extends only partially down the side surface of the electrical component without reaching a bottom surface of the electrical component or the substrate, and wherein a third gap remains between a top surface of the underfill material and a bottom surface of the TIM in the lateral gap.
2 . The semiconductor device of claim 1 , wherein the TIM includes liquid metal.
3 . The semiconductor device of claim 1 , wherein the heat sink includes:
a horizontal step; and
a riser extending from the horizontal step to the cover.
4 . The semiconductor device of claim 1 , wherein the wall includes a vent hole, and wherein the TIM extends to the vent hole.
5 . The semiconductor device of claim 1 , wherein the cover includes a vent hole.
6 . The semiconductor device of claim 1 , wherein the TIM physically contacts both a side surface of the electrical component and a surface of the wall, thereby spanning a gap between the wall and electrical component.
7 . A semiconductor device, comprising:
a substrate, wherein the substrate includes a plurality of conductive layers and a plurality of insulating layers;
a dam material disposed on the substrate, wherein the dam material is formed of solder resist;
an electrical component disposed on the substrate within a boundary defined by the dam material, wherein the dam material extends continuously and completely around a perimeter of the electrical component in plan view, and wherein a solder bump of the electrical component extends to the substrate;
an underfill material extending around the solder bump and filling a first gap between substrate and electrical component, wherein the underfill material extends to the dam material on two opposing sides of the electrical component;
a heat sink disposed over the electrical component, wherein the heat sink includes,
a cover,
a wall extending from the cover forming a pocket around a perimeter of the electrical component, wherein the wall is positioned directly over the dam material, and
a first adhesive disposed between the cover and the wall, wherein the wall is bonded to the cover by the first adhesive;
a second adhesive disposed between the wall and the dam material, wherein the wall is bonded to the dam material by the second adhesive; and
a thermal interface material (TIM) disposed between the electrical component and heat sink, wherein the TIM physically contacts both a side surface of the electrical component and a surface of the wall, thereby spanning a second gap between the wall and electrical component, and wherein a third gap remains between a top surface of the underfill material and a bottom surface of the TIM in the second gap.
8 . The semiconductor device of claim 7 , wherein the TIM remains contained within the pocket by the wall.
9 . The semiconductor device of claim 7 , wherein the TIM includes liquid metal.
10 . The semiconductor device of claim 7 , wherein the heat sink includes:
a horizontal step; and
a riser extending from the horizontal step to the cover.
11 . The semiconductor device of claim 7 , wherein the wall includes a vent hole.
12 . The semiconductor device of claim 7 , wherein the cover includes a vent hole.
13 . The semiconductor device of claim 7 , wherein the wall is bonded to a surface of the cover.
14 . A method of making a semiconductor device, comprising:
providing a semiconductor die;
disposing an underfill material under the semiconductor die;
disposing a thermal interface material (TIM) on a top surface of the semiconductor die, wherein the TIM is disposed to be contained completely on the top surface without extending outside a footprint of the semiconductor die; and
disposing a heat sink over the semiconductor die after disposing the TIM on the top surface of the semiconductor die, wherein the heat sink includes a cover with a wall extending from the cover forming a pocket around a perimeter of the semiconductor die, wherein the pocket includes a lateral gap between the wall and the semiconductor die such that the semiconductor die does not directly physically contact the wall, wherein the wall is a unibody extension of the cover, wherein the heat sink presses the TIM such that the TIM is routed down and directly physically contacts a side surface of the semiconductor die but remains contained within the pocket by physical contact with the wall, and wherein a vertical gap remains between a top surface of the underfill material and a bottom surface of the TIM after disposing the heat sink.
15 . The method of claim 14 , wherein the TIM includes liquid metal.
16 . The method of claim 14 , further including providing the heat sink to include:
a horizontal step; and
a riser extending from the horizontal step to the cover.
17 . The method of claim 14 , further including forming a vent hole in the wall.
18 . The method of claim 14 , further including forming a vent hole in the cover.
19 . A method of making a semiconductor device, comprising:
providing a substrate, wherein the substrate includes a plurality of conductive layers and a plurality of insulating layers;
disposing a dam material on the substrate;
disposing an electrical component on the substrate within a boundary defined by the dam material, wherein the dam material extends continuously and completely around a perimeter of the electrical component in plan view;
disposing an underfill material between the substrate and electrical component;
disposing a thermal-interface material (TIM) over the electrical component, wherein the TIM extends down a side surface of the electrical component while a vertical gap remains between a top surface of the underfill material and a bottom surface of the TIM;
disposing a heat sink over the electrical component, wherein the heat sink includes a cover with a wall extending from the cover forming a pocket around a perimeter of the electrical component, and wherein the heat sink is positioned with the wall directly over the dam material; and
disposing an adhesive between the wall and the dam material.
20 . The method of claim 19 , wherein the TIM remains contained within the pocket by the wall.
21 . The method of claim 20 , wherein the TIM includes liquid metal.
22 . The method of claim 19 , further including providing the heat sink to include:
a horizontal step; and
a riser extending from the horizontal step to the cover.
23 . The method of claim 19 , further including forming a vent hole in the wall.
24 . The method of claim 19 , further including forming a vent hole in the cover.