Electronic assemblies, such as microprocessors and power electronics chips, may generate significant heat during operation which requires cooling in order to keep the electronic assemblies within their operating temperature range. Conventional cooling systems can involve passing a cooling fluid across electronic assembles to cool the electronic assembly and maintain the electronic assembly within its operating temperature range.
Micro-coolers may be used to cool electronic devices. In small scale applications, it may be difficult to maintain adequate cooling fluid coverage across the entire micro-cooler, especially at higher temperatures and/or hot spot heat fluxes. Therefore, there exists a need for a micro-cooler for cooling electronic devices which is capable of providing adequate cooling fluid coverage even on a small scale.
Embodiments of the present disclosure are directed to micro-cooler assemblies for cooling electronic devices. The micro-cooler assemblies described herein may include a manifold and a cold plate placed on top of an electronic device. Cooling fluid may be flowed through micro-channels formed in the micro-cooler via wicking action. Heat from the electronic device may vaporize the cooling fluid. The vaporized cooling fluid may pass through vapor gaps formed between the microchannels. The cooling fluid may return to a liquid supply to be re-cooled and re-used.
In one embodiment, a micro-cooler assembly includes a manifold having at least one inlet for receiving a liquid, a plurality of fins, wherein each fin of the plurality of fins includes a micro-channel, and a plurality of vapor gaps interlaced with the plurality of fins. A width of the micro-channels is graded. The micro-cooler assembly further includes a cold plate that includes a surface and a wick region disposed on the surface. The manifold is coupled to the surface of the cold plate. The at least one inlet is operable to provide the liquid proximate the wick region. The liquid is operable to be wicked into the wick region through the micro-channels of the plurality of fins, and heating of the liquid changes phase to a vapor that exits the manifold through the plurality of vapor gaps.
In another embodiment, a micro-cooler array includes an array of manifolds and a cold plate. Each manifold includes a plurality of fins, where each fin of the plurality of fins includes a micro-channel. Each manifold also includes a plurality of vapor gaps interlaced with the plurality of fins. The micro-cooler array also includes a central inlet for receiving a liquid centrally disposed within the array of manifolds. The cold plate includes an array of wick regions vertically aligned with the array of manifolds. The cold plate also includes an inlet distribution path positioned between individual wick regions of the array of wick regions. The inlet distribution path includes a plurality of micro-structures. The array of manifolds is coupled to a surface of the cold plate. The central inlet is operable to provide the liquid to a central location with respect to the array of wick regions, and the liquid is operable to be wicked within the inlet distribution path and into the array of wick regions through the micro-channels of the plurality of fins. Heating of the liquid changes phase to a vapor that exits the array of manifolds through the plurality of vapor gaps.
In another embodiment, a micro-cooler array includes an array of manifolds and a cold plate. Each manifold includes an inlet manifold, a plurality of fins, where each fin of the plurality of fins includes a micro-channel and has a right angle shape, and a plurality of vapor gaps interlaced with the plurality of fins. The micro-cooler array also includes a plurality of inlets for receiving a liquid disposed within the array of inlet manifolds of the array of manifolds. The cold plate includes an array of wick regions vertically aligned with the array of manifolds. The plurality of inlets is operable to provide the liquid to the array of wick regions. The liquid is operable to be wicked into the array of wick regions through the micro-channels of the plurality of fins. Heating of the liquid changes phase to a vapor that exits the array of manifolds through the plurality of vapor gaps.
To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.
Embodiments of the present disclosure are directed to micro-cooler assemblies for cooling electronic devices. The micro-cooler assemblies described herein may include a manifold and a cold plate placed on top of an electronic device. Cooling fluid may be flowed through microchannels formed in the micro-cooler via wicking action. Heat from the electronic device may vaporize the cooling fluid. The vaporized cooling fluid may pass through vapor gaps formed between the microchannels. The cooling fluid may return to a liquid supply to be re-cooled and re-used.
Conventional micro-cooler assemblies may not provide even fluid distribution across the entire electronic device, especially in small scale applications and/or when the electronic device has localized hot spots. Embodiments can more evenly distribute cooling fluid across the entire electronic device, while effectively evacuating vapor, compared to conventional micro-cooler assemblies.
Referring now to
The manifold 104 has one or more inlets 106 operable to introduce a liquid onto the front surface 116 of the cold plate 114. In the illustrated embodiment, the manifold 104 has two inlets 106; however, more or fewer inlets 106 may be provided. The example inlets 106 are cylindrical in shape but embodiments are not limited thereto. The inlets 106 may be configured as couplings operate to receive fluid lines that fluidly couple the inlets 106 to a liquid reservoir (not shown).
The manifold also includes a plurality of vapor gaps 108 interlaced between a plurality of fins 134. The vapor gaps 108 of the illustrated embodiment are configured as slots within the material of the manifold 104; however, the vapor gaps 108 may take on other shapes. Any number of vapor gaps 108 may be utilized depending on the application. As described in more detail below, the vapor gaps 108 are provided to remove vapor generated by the heating of the liquid introduced into the wick region 120 of the cold plate 114 caused by the heat generating component 128, which may be an electronic device, such as a power electronic device or a microchip.
Referring now to
The lower surface 112 of the manifold 104 includes one or more inlet regions 124 fluidly coupled to the one or more inlets 106. In the illustrated embodiment, there are two inlet regions 124 for the two inlets 106. The inlet regions 124 are configured as recesses within the lower surface 112 of the manifold 104 such that a gap is present when the lower surface 112 of the manifold 104 is coupled to the front surface 116 of the cold plate 114. Liquid that is introduced into the inlet regions 124 is then wicked toward the vapor gaps 108 and thus the heat transfer wick region 120. In some embodiments, a micro-pillar array 126 is provided within the inlet regions 124 to further optimize flow and facilitate wicking of fluid toward the heat transfer wick region 120 as well as provide additional surface area for heat transfer.
Referring now to
Each fin 134 has a micro-channel 136 that is exposed to the inlet regions 124 to receive liquid 122 as shown by the horizontal arrows. The micro-channels 136 draw the liquid toward the wick region 120 by a wicking capillary force. The liquid 122 is then substantially uniformly distributed along the wick region 120, where it is heated and turned into a vapor 138 by heat 192 generated by a heat generating component. Excess liquid travels laterally across the cold plate 114 and may then exit through drains (not shown), which may be configured as holes within the cold plate 114.
As a non-limiting example, the micro-cooler assembly 102 is designed to cool a 0.5 cm×0.5 cm microprocessor footprint area that is designed for efficient liquid delivery and vapor extraction to achieve complete vapor-liquid phase separation or vapor exit quality of approximately 1. The wick region 120 may be configured as a 25 μm thick MIO structure with a 0.5 cm×0.5 cm footprint area. The width of the micro-channel 136 Wch and the width of the fin walls Wwall may be 100 μm. The height hch of the micro-channel 136 may be 300 μm. It should be understood that these dimensions are provided for illustrative purposes only, and that other dimensions may be utilized depending on the application.
In some embodiments, the width Wch of the micro-channels 136 within the fins 134 may be graded to provide optimal liquid distribution on the wick region. Referring to
Additionally, the size of the vapor gap 108 (i.e., the width between fins 134) may also be graded. The grading may be provided in any direction to enhance the removal of vapor.
An example non-limiting method of fabricating a cold plate 114 is now described. Referring to
Referring to
Next in
Next, as shown in
In
An example non-limiting method of fabricating a manifold 104 is now described. Referring to
As shown in
Another photoresist 154 pattern is applied to the backside of the wafer as shown in
An etching process (e.g., DRIE) is performed until the vapor gaps 108 extend fully through the silicon substrate 152, as shown in
Finally, any remaining photoresist is removed by immersing the wafer in a solution, such as Piranha solution. The result is shown in
The designs described herein can be tiled together to form a micro-cooler array 162 that is used to cool an electronic device array 156, as shown in
The manifolds 104 have the fins 134 and vapor gaps 108 as described above. Additionally, a wick region 120 is provided on the cold plate 164 beneath each manifold 104. In the illustrated embodiment, an inlet 106 may be centrally provided (not shown) with respect to each of the manifolds 104. Therefore, a single inlet 106 feeds liquid to each manifold 104 and thus each wick region 120 of the cold plate 114 positioned beneath each manifold 104. Additionally, a drainage path 160 is provided between adjacent manifolds to provide an area for excess liquid to flow.
Referring now to
The liquid feed manifold layer 194 includes an array of right angle fins 186 that define an array of right angle vapor gaps 188. Each right angle fin 186 includes a micro-channel 136 (not visible in
It should now be understood that embodiments are directed to capillary-assisted micro-cooler assemblies that combine a three-dimensional silicon microchannel manifold with a silicon cold plate having a porous wick structure. Micro-fabrication techniques are used to fabricate the silicon-based microchannel manifold and the cold plate. The microporous wick region has a same area as a heat generating component that is to be cooled.
It may be noted that one or more of the following claims utilize the terms “where,” “wherein,” or “in which” as transitional phrases. For the purposes of defining the present technology, it may be noted that these terms are introduced in the claims as an open-ended transitional phrase that are used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”
It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure.
Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it may be noted that the various details described in this disclosure should not be taken to imply that these details relate to elements that are essential components of the various embodiments described in this disclosure, even in casings where a particular element may be illustrated in each of the drawings that accompany the present description. Rather, the claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described in this disclosure. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.
This application claims priority to U.S. Provisional Application No. 63/608,716, filed Dec. 11, 2023, which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63608716 | Dec 2023 | US |