Protective enclosure for an electronic device
A protective enclosure for a PCB assembly, e.g., a solid-state-drive assembly. In an example embodiment, the enclosure comprises a flexible, stamped-metal heat spreader connected, by way of cured-liquid TIM parts, to at least some of the packaged integrated circuits on one side of the PCB assembly. In some embodiments, additional cured-liquid TIM parts may be connected between the body of the protective enclosure and packaged integrated circuits on the other side of the PCB assembly and/or the assembly's PCB. The PCB assembly, heat spreader, and various TIM parts are arranged in a manner that helps to significantly lower the risk of solder-joint failure under thermal cycling.
1. An apparatus, comprising:
an enclosure comprising a base and a lid attached to one another;
a printed-circuit-board assembly in the enclosure, the printed-circuit-board assembly comprising a printed circuit board and a plurality of electronic components attached to the printed circuit board;
a heat spreader in the enclosure, the heat spreader being a stamped sheet-metal part having a plurality of legs, each of the legs being fixedly attached to an inner main surface of the lid; and
one or more first thermal-interface-material (TIM) parts, each of the one or more first TIM parts being in contact with and vertically between the heat spreader and a corresponding one of the electronic components,
wherein the stamped sheet-metal part is shaped such that:
a first flat portion of the stamped sheet-metal part facing the inner main surface of the lid is at a first nonzero vertical distance from the inner main surface and is parallel to the inner main surface; and
a second flat portion of the stamped sheet-metal part facing the inner main surface of the lid is at a second vertical distance from the inner main surface and is parallel to the inner main surface, the second vertical distance being larger than the first nonzero vertical distance.
2. The apparatus of claim 1 , further comprising one or more second TIM parts, each of the one or more second TIM parts being in contact with and vertically between the base and a respective one of the electronic components.
3. The apparatus of claim 2 , further comprising one or more third TIM parts, each of the one or more third TIM parts being in contact with and vertically between the base and the printed circuit board.
4. The apparatus of claim 3 , wherein the first, second, and third TIM parts are cured-liquid TIM parts.
5. The apparatus of claim 1 , wherein the electronic components are attached and electrically connected to the printed circuit board using solder joints.
6. The apparatus of claim 1 , wherein the stamped sheet-metal part is flexible to allow for vertical displacement of a section thereof when the printed-circuit-board assembly is subjected to thermal cycling.
7. The apparatus of claim 1 ,
wherein the base and the lid are attached to one another using one or more first fastening elements, each of which is not in contact with the printed circuit board; and
wherein the printed circuit board is attached to the base using one or more second fastening elements, each of which is not in contact with the lid.
8. The apparatus of claim 1 , wherein the electronic components include one or more of the following:
a flash memory chip;
a processor or controller chip;
a dynamic random-access memory chip; and
a power-management chip.
9. The apparatus of claim 1 , wherein the apparatus comprises a solid-state drive.
10. The apparatus of claim 1 , further comprising one or more second TIM parts, each of the one or more second TIM parts being in contact with and vertically between a respective one of the legs of the stamped sheet-metal part and a respective portion of the inner main surface of the lid.
11. The apparatus of claim 10 , wherein each one of the second TIM parts is a piece of thermal adhesive tape.
12. The apparatus of claim 1 , wherein the plurality of legs includes more than four legs.
13. The apparatus of claim 1 , wherein neither the first flat portion nor the second flat portion of the stamped sheet-metal part is in direct contact with the lid.
14. A manufacturing method, comprising:
attaching a printed-circuit-board assembly to a base, the printed-circuit-board assembly comprising a printed circuit board and a plurality of electronic components attached to the printed circuit board;
forming a sub-assembly by attaching a heat spreader to a lid, the heat spreader being a stamped sheet-metal part having a plurality of legs, each of the legs being fixedly attached to an inner main surface of the lid;
depositing one or more drops of a fluid thermal-interface material onto the subassembly; and
attaching the subassembly to the base to enclose the printed-circuit-board assembly therebetween such that each of the one or more drops is in contact with and vertically between the heat spreader and a corresponding one of the electronic components,
wherein the stamped sheet-metal part is shaped such that after the attaching:
a first flat portion of the stamped sheet-metal part facing the inner main surface of the lid is at a first nonzero vertical distance from the inner main surface and is parallel to the inner main surface; and
a second flat portion of the stamped sheet-metal part facing the inner main surface of the lid is at a second vertical distance from the inner main surface and is parallel to the inner main surface, the second vertical distance being larger than the first nonzero vertical distance.
15. The method of claim 14 , further comprising curing the drops.
16. The method of claim 14 , further comprising depositing additional drops of the fluid TIM onto the base prior to the attaching the printed-circuit-board assembly to the base.
17. The method of claim 14 , wherein the electronic components are attached and electrically connected to the printed circuit board using solder joints.
18. The method of claim 14 , wherein the stamped sheet-metal part is flexible to allow for vertical displacement of a section thereof when the printed-circuit-board assembly is subjected to thermal cycling.
19. The method of claim 14 , further comprising:
attaching the base and the lid to one another using one or more first fastening elements, each of which is not in contact with the printed circuit board; and
attaching the printed circuit board to the base using one or more second fastening elements, each of which is not in contact with the lid.
20. The method of claim 14 , wherein the printed-circuit-board assembly implements a solid-state drive.