Electronic assembly

Abstract

This disclosure relates to an electronic component including a heat sink with a channel formed by cutting the heat sink. A thermal interface material is disposed between the heat sink and an electronic device. A compressible filler is disposed in the channel to surround and confine the thermal interface material.

Description

Electronic component This disclosure relates to the cooling of electronic devices. Electronic devices such as central processing units (CPUs), graphics processing units (GPUs), and application specific integrated circuits (ASICs) generate a large amount of heat and thus need to be cooled for normal operation. One way to cool an electronic device is to connect a heat sink to the electronic device. The heat sink serves as a heat exchanger that dissipates the heat generated by the electronic device to the ambient space when used for air cooling, or dissipates the heat to a coolant when used for immersion cooling. A thermal interface material is disposed between the electronic device and the heat sink to facilitate heat transfer from the electronic device to the heat sink. The thermal interface material includes, for example, a thermal pad, a thermal adhesive, a thermal filler, a graphite sheet, a phase change material, a liquid metal, etc. The thermal interface material is adhered or laid on a flat surface of the heat sink and further attached to the electronic device. When the thermal interface material is compressed between the heat sink and the electronic device, especially when the thermal interface material is in a liquid phase, the thermal interface material may overflow. Therefore, the thermal interface material may leak and contaminate nearby components, damage the integrated circuit (IC) socket, cause an electrical short circuit, or other permanent damage. In an immersion cooling system, compatibility issues limit the selection of thermal interface materials. For example, a thermal paste cannot be used when hydrocarbon oil is used as a coolant for immersion cooling. After a period of time, the hydrocarbon oil will wash away the thermal paste and reduce its heat transfer ability. In addition, the washed-away thermal paste will change the properties of the hydrocarbon oil. Generally, there is no specific limiting mechanism designed for thermal interface materials. In cases where the thermal interface material is conductive and in a liquid state at high temperatures, such as liquid metal, a sponge or gasket is directly bonded to the flat surface of the heat sink to surround the thermal interface material. Sponges and adhesives are not oil-resistant, thus limiting their application in immersion cooling systems. Sponges and adhesives also cannot provide a rigid structure and may still cause leakage of the thermal interface material. Tapes and foams can also be used to limit the thermal interface material, but have similar problems to sponges and adhesives in preventing leakage of the thermal interface material. In one embodiment, the electronic component includes a heat sink, an electronic device, a thermal interface material, and a compressible filler. The heat sink has a first channel formed by cutting on its surface. The thermal interface material is disposed between the heat sink and the electronic device, adheres to the surface of the heat sink and the surface of the electronic device, and is disposed within the perimeter of the compressible filler. The compressible filler is disposed in the first channel to completely surround and limit the thermal interface material. In another embodiment, the electronic component includes a heat sink, an electronic device, a thermal interface material, and a compressible filler. The heat sink has a continuous channel formed by cutting on its bottom surface. The thermal interface material is disposed between the heat sink and the electronic device, wherein the thermal interface material directly contacts the bottom surface of the heat sink and directly contacts the top surface of the electronic device. The compressible filler is fixed in the continuous channel in a non-adhesive manner and completely surrounds the thermal interface material. Those of ordinary skill in the art to which this disclosure pertains, upon reviewing this disclosure including the claims and in conjunction with the appended drawings, should be able to fully understand the technical features of this disclosure. The embodiments of this disclosure can confine the thermal interface material within a specific area to prevent leakage, prevent deterioration of the thermal interface material, and enable a wider selection of thermal interface materials. This disclosure illustrates numerous specific details, such as components, elements, structures, and methods, to facilitate a thorough understanding of the embodiments of this disclosure. However, those of ordinary skill in the art will be able to understand that this disclosure can still be implemented by omitting one or more specific details. In other cases, well-known details are not shown or described to avoid obscuring the direction of this disclosure. As shown in FIG. 1, it is a front view of the bottom of a heat sink 100 according to an embodiment of this disclosure. The bottom serves as the base of the heat sink 100. The bottom has a relatively flat and smooth bottom surface 104, and a continuous channel 101 is formed by cutting on the bottom surface 104. A thermal interface material 103 is disposed on the bottom surface 104, and the channel 101 forms a closed perimeter that completely surrounds the thermal interface material 103. The channel 101 can be a groove, a slot, or other structures that form a depth relative to the plane of the bottom surface 104, which is used to hold and confine a compressible filler (such as a compressible filler 152 shown in FIG. 3). There is an overflow area 102 between the channel 101 and the thermal interface material 103, and when compressed between the heat sink 100 and an electronic device (such as an electronic device 150 shown in FIG. 3), the thermal interface material 103 overflows into the overflow area 102. FIG. 2 shows a cross-sectional view of an electronic component 120 according to an embodiment of this disclosure. As an example shown in FIG. 2, for ease of illustration, the heat sink 100 shown therein has a plurality of fins 156. It can be understood that the heat sink 100 can also be a water-cooled plate or other heat dissipation structures. As shown in FIG. 2, the aforementioned heat sink 100 is attached to an electronic device 150 (such as a CPU, GPU, ASIC, etc.). The electronic device 150 is mounted on a surface 155 of a substrate 151, and in one embodiment, the substrate 151 is a printed circuit board (PCB). The substrate 151 can be, for example, the motherboard of a server computer. As shown in the example of FIG. 2, the thermal interface material 103 is directly disposed on its bottom surface 104 and is located within the perimeter of the channel 101. A top surface 153 of the electronic device 150 faces the thermal interface material 103, and a bottom surface 154 of the electronic device 150 faces the substrate 151. FIG. 3 shows a cross-sectional view of the electronic component 120 according to an embodiment of the present disclosure. As shown in FIG. 3, the heat sink 100 is attached to the electronic device 150. A compressible filler 152 is inserted into the channel 101, and when the heat sink 100 is attached to the electronic device 150, the compressible filler 152 is compressed together with the thermal interface material 103 onto the top surface 153 of the electronic device 150 (as shown in FIG. 2). When pressing against the electronic device 150, the compressible filler 152 and the thermal interface material 103 directly contact the top surface 153 of the electronic device 150. When the thermal interface material 103 presses against the electronic device 150, it overflows into the overflow region 102 (as shown in FIG. 1). As shown in the example of FIG. 3, the channel 101 does not extend beyond the perimeter of the electronic device 150. More specifically, in the example shown in FIG. 3, the channel 101 can be aligned with the perimeter of the electronic device 150 or slightly located within the perimeter of the electronic device 150. The heat generated by the electronic device 150 is transferred to the heat sink 100 via the thermal interface material 103. The compressible filler 152 completely surrounds the thermal interface material 103. The compressible filler 152 is firmly held and constrained in the channel 101, and it forms a continuous and solid structure that confines the thermal interface material 103 within the perimeter of the compressible filler 152 and prevents external fluids from reaching the thermal interface material 103. Thereby, it prevents the thermal interface material 103 from leaking outside the perimeter of the compressible filler 152 and prevents the thermal interface material 103 from being contaminated by the coolant in immersion cooling applications. The compressible filler 152 can include rubber or other compressible materials suitable for specific cooling applications. For example, the compressible filler 152 can be a rubber sponge. The compressible filler 152 follows the shape / contour of the channel 101. The compressible filler 152 can be interference-fitted into the channel 101 without glue or other adhesives. For specific cooling applications, not using adhesives allows for a wider selection of thermal interface materials. FIG. 4 shows a cross-sectional view of the electronic component 120 according to an embodiment of the present disclosure. In the example of the figure, as shown in FIG. 4, a heat sink 200 is the same as the heat sink 100 of the aforementioned electronic component 120, except that a continuous overflow channel 201 is added within the perimeter of the channel 101. The overflow channel 201 has the same shape and structure as the channel 101, except that the depth of the overflow channel 201 is shallower than the depth of the channel 101. The overflow channel 201 is disposed separately from the channel 101. The electronic components 220 and 120 with the same reference numerals have the same components in other aspects. FIG. 5 shows a cross-sectional view of the electronic component 220 according to an embodiment of the present disclosure. FIG. 5 shows the heat sink 200 after being attached to the electronic device 150. As described above, when the heat sink 200 is attached to the electronic device 150, the compressible filler 152 is inserted into the channel 101 and compressed together with the thermal interface material 103 against the top surface 153 of the electronic device 150 (as shown in FIG. 4). When the thermal interface material 103 presses against the electronic device 150, the thermal interface material 103 overflows into the overflow channel 201. It should be noted that the portion of the thermal interface material 103 located in the overflow channel 201 does not contact the compressible filler 152 in the channel 101. When the thermal interface material 103 is compressed, shear stress is applied thereto, which may cause the thermal interface material 103 to be thicker at the corners than in the central region. The overflow channel 201 receives the overflowing thermal interface material 103, allowing the thermal interface material 103 to be evenly distributed on the electronic device 150. FIG. 6 shows a cross-sectional view of the electronic component 220 according to an embodiment of the present disclosure. In the example shown in FIG. 6, a heat sink 300 is substantially the same as the heat sink 200 of the aforementioned electronic component 220, except for a continuous overflow channel 301. The overflow channel 301 is substantially the same as the overflow channel 201 of the aforementioned heat sink 200, except that the overflow channel 301 is directly adjacent to the outside of the channel 101. Similar to the overflow channel 201 of the aforementioned heat sink 200, the overflow channel 301 of the heat sink 300 is located within the perimeter of the channel 101 and has a depth shallower than the depth of the channel 101. The electronic components 320 and 220 with the same reference numerals have the same components in other aspects. FIG. 7 shows a cross-sectional view of an electronic component 320 according to an embodiment of the present disclosure. FIG. 7 shows a heat sink 300 attached to the electronic device 150. As described above, when the heat sink 300 is attached to the electronic device 150, the compressible filler 152 is inserted into the channel 101 and compressed together with the thermal interface material 103 against the top surface 153 of the electronic device 150 (as shown in FIG. 6). When the thermal interface material 103 is pressed against the electronic device 150, the thermal interface material 103 overflows into the overflow channel 301. Compared with the overflow channel 201 of the heat sink 200 described above, the portion of the thermal interface material 103 located in the overflow channel 301 directly contacts the compressible filler 152 in the channel 101. FIG. 8 shows a cross-sectional view of an electronic component 420 according to an embodiment of the present disclosure. As an example shown in FIG. 8, a heat sink 400 is substantially the same as the heat sink 100 of the electronic component 120 described above, except for a continuous channel 401. The channel 401 is substantially the same as the channel 101 of the heat sink 100 described above, except that when the heat sink 400 is attached to the electronic device 150, the channel 401 is located outside the periphery of the electronic device 150, which results in a compressible filler 402 (as shown in FIG. 9) in the channel 401 being located outside the periphery of the electronic device 150. The electronic components 120 and 420 with the same reference numerals have the same components in other respects. FIG. 9 shows a cross-sectional view of an electronic component 420 according to an embodiment of the present disclosure. FIG. 9 shows a heat sink 400 attached to the electronic device 150. When the heat sink 400 is attached to the electronic device 150, the compressible filler 402 is inserted into the channel 401 and pressed together with the thermal interface material 103 against the substrate 151. The thermal interface material 103 is compressed against the top surface 153 of the electronic device 150 (as shown in FIG. 8), and the compressible filler 402 is compressed against the surface 155 of the substrate 151. Similar to the compressible filler 152 of the electronic component 120 described above, the compressible filler 402 may include rubber or other suitable compressible materials. For example, the compressible filler 402 may be a rubber sponge. The compressible filler 402 follows the shape / contour of the channel 401. The compressible filler 402 completely surrounds the electronic device 150 and the thermal interface material 103. By arranging the channel 401 outside the periphery of the electronic device 150, the channel 401 can be made shallower than the channel 101 of the heat sink 100 of the electronic component 120 described above, and the compressible filler 402 is arranged on the side of the electronic device 150 instead of the top. This configuration improves the heat transfer performance and slightly expands the coverage area of the thermal interface material 103 on the electronic device 150. The thermal interface material 103 may include liquid metal, thermal paste, or other thermal interface materials suitable for specific cooling applications. It can be understood that the embodiments of the present disclosure allow for a wider selection of thermal interface materials. For example, the embodiments of the present disclosure allow the use of thermal paste as the thermal interface material in an immersion cooling system because the compressible fillers (152, 402) in the channels (101, 401) of the embodiments can prevent the leakage of the thermal paste and prevent the thermal capacitance from contacting the coolant. The electronic components disclosed herein may be immersed in the coolant of an immersion cooling system. It can be understood that although the embodiments of the present disclosure are particularly advantageous for immersion cooling systems, these embodiments are also advantageous for air cooling systems or other cooling systems. The above specific embodiments are only explanations of the present disclosure and are not intended to limit the present disclosure. Those of ordinary skill in the technical field to which the present disclosure pertains can make obvious modifications to these embodiments as needed after reading this specification, and all of them are equally included within the scope of the present disclosure. 100: Heat sink 101: Channel 102: Overflow area 103: Thermal interface material 104: Bottom surface 120: Electronic component 150: Electronic device 151: Substrate 152: Compressible filler 153: Top surface 154: Bottom surface 155: Surface 156: Fin 200: Heat sink 201: Overflow channel 220: Electronic component 300: Heat sink 301: Overflow channel 320: Electronic component 400: Heat sink 401: Channel 402: Compressible filler 420: Electronic component The technical content of the present disclosure can be more comprehensively understood by referring to the detailed description and the claims and in combination with the accompanying drawings. The drawings are not drawn to scale. FIG. 1 shows a bottom side view of a heat sink in an embodiment of the present disclosure. FIGS. 2 and 3 show cross-sectional views of an electronic component in an embodiment of the present disclosure. FIGS. 4 and 5 show cross-sectional views of an electronic component in another embodiment of the present disclosure. FIGS. 6 and 7 show cross-sectional views of an electronic component in yet another embodiment of the present disclosure. FIGS. 8 and 9 show cross-sectional views of an electronic component in yet another embodiment of the present disclosure. 100: Heat sink 101: Channel 102: Overflow area 103: Thermal interface material 104: Bottom surface

Claims

1. An electronic component, comprising: A heat sink, on one surface of which a channel and an overflow channel are cut to form, wherein the depth of the overflow channel is shallower than the depth of the channel; an electronic device; a thermal interface material disposed between the heat sink and the electronic device, the thermal interface material being attached to the surface of the heat sink and the surface of the electronic device, and the overflow channel being located within the perimeter of the first channel and accommodating an overflow portion of the thermal interface material. And a compressible filler disposed in the channel, the compressible filler completely surrounding the thermal interface material and confining the thermal interface material within the perimeter formed by the compressible filler.

2. The electronic component as claimed in claim 1, wherein the compressible filler contacts the surface of the electronic device.

3. The electronic component as described in claim 1, further comprising: A substrate, wherein the electronic device is attached to a surface of the substrate.

4. The electronic component as claimed in claim 4, wherein the compressible filler contacts the surface of the substrate.

5. The electronic component as claimed in claim 1, wherein the compressible filler is disposed outside the periphery of the electronic device.

6. The electronic component as claimed in claim 1, wherein the electronic device is a central processing unit (CPU), a graphics processing unit (GPU), or an application-specific integrated circuit (ASIC).

7. The electronic component as claimed in claim 1, wherein the compressible filler is fixed in the first channel in an adhesive-free manner.

8. The electronic component as claimed in claim 1, wherein the compressible filler is fixed in the first channel by an interference fit.

9. The electronic component as claimed in claim 1, wherein the thermal interface material comprises thermal paste or liquid metal.

10. In the electronic assembly as claimed in claim 1, wherein the overflow channel is configured separately from the channel.

11. In the electronic assembly of claim 1, wherein the overflow channel is directly adjacent to the outside of the channel.

12. An electronic component, comprising: A heat sink, wherein a continuous channel and an overflow channel are cut into a bottom surface of the heat sink, wherein the depth of the overflow channel is shallower than the depth of the continuous channel; an electronic device; a thermal interface material disposed between the heat sink and the electronic device, wherein the thermal interface material directly contacts the bottom surface of the heat sink and directly contacts a top surface of the electronic device, and the overflow channel accommodates an overflow portion of the thermal interface material; and a compressible filler fixed in the continuous channel in an adhesive-free manner and completely surrounding the thermal interface material.

13. The electronic component as claimed in claim 12, wherein the continuous channel extends beyond one periphery of the electronic device.

14. The electronic assembly as claimed in claim 12, wherein the compressible filler is in direct contact with the top surface of the electronic device.

15. The electronic component as described in claim 12, further comprising: A printed circuit board (PCB) wherein the electronic device is attached to one surface of the printed circuit board.

16. The electronic component of claim 15, wherein the compressible filler is in direct contact with the surface of the printed circuit board.

17. In the electronic assembly as claimed in claim 12, wherein the overflow channel is configured separately from the channel.

18. In the electronic assembly of claim 12, the overflow channel is directly adjacent to the outside of the channel.

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