JP6041801B2 - Flexible heat exchanger - Google Patents

Description

  The present invention generally relates to a liquid flow through (LFT) heat exchanger that cools a printed circuit board (PCB) device or other semiconductor device or component. More specifically, the present invention relates to a heat exchanger of the above type that is flexible and easily adaptable for use in semiconductor devices of various heights and other dimensions.

  High performance computing systems use unprecedented amounts of power at high power densities. For this reason, the requirements for cooling the system have become more stringent and it is essential to consider solutions using liquid cooling. Currently available liquid cooling techniques include the heat pipe method, the vapor chamber method, and the liquid flow (LFT) method. On the other hand, these solutions tend to be quite expensive.

  In systems that use liquid cooling, it may also be necessary to place components that remove heat in physical contact with an overlying semiconductor device, such as a PCB assembly. However, the sizes of adjacent semiconductor devices may be different. Moreover, two semiconductor devices of the same type may actually have different dimensions one by one, even though the dimensions are within acceptable tolerances. For this reason, it can be difficult to provide a heat exchanger component that can be substantially adapted to the size requirements created by such different devices. In general, thermal interface materials (TIM) are used by those skilled in the art to perform the function of filling the gap (eg, gels, greases, heat dissipation putty, etc.). However, this reduces heat transfer efficiency. Thus, improvements are needed in the current state of the art.

  According to one aspect of the invention, a method is provided for constructing a heat exchanger that cools one or more semiconductor components. The method includes providing a first planar sheet and a second planar sheet of a predetermined thermally conductive metal foil, each sheet having an outer surface and an inner surface. The method further includes forming one or more thermal contact nodes (TCNs) on the first sheet, each TCN protruding outward from the outer surface of the first sheet, the planar contact member And one or more side portions. The side portions may each include a group of elastic components that jointly allow the contact member of the TCN to move toward and away from the outer surface of the first sheet, and the side portion of the TCN and the contact member jointly include a coolant. Forming a chamber; Each TCN can be formed with a variety of geometric shapes, and each TCN functions substantially independently and mechanically, so multiple TCNs thus formed can have different device heights. It can correspond to. Conduit segments are configured along the inner surface of the first sheet and / or the second sheet, each conduit segment being selectively between two TCN coolant chambers or between the TCN coolant chamber and input port or It extends between the output ports. The method further joins the inner surface of the second sheet to the inner surface of the first sheet to form a closed flow path that includes each conduit segment and allows coolant to enter and exit the coolant chamber of each TCN. Includes steps. The method further includes connector means for connecting or disconnecting the coolant stream to or from the present invention.

  In accordance with another aspect of the present invention, a heat exchange apparatus is provided for cooling one or more semiconductor components, the apparatus comprising: a first plane of a predetermined thermally conductive metal foil having an outer surface and an inner surface. One or more thermal contact nodes (TCN) are formed in the first sheet, each TCN protruding outward from the outer surface of the first sheet, and the planar contact member and one or more Each of which includes a resilient component group that jointly enables the contact member of the TCN to move toward and away from the outer surface of the first sheet, the side portion of the TCN and the contact member, Together, a coolant chamber is formed, and a conduit segment is configured along the inner surface of the first sheet, each conduit segment being selectively between two or more TCN coolant chambers or cooling the TCN. A first planar sheet extending between the chamber and the input or output port; a second planar sheet of a predetermined thermally conductive metal foil as described above having an outer surface and an inner surface; and each conduit segment including each conduit segment Means for joining the inner surface of the second sheet to the inner surface of the first sheet to form a closed flow path that allows the coolant to enter and exit the coolant chamber;

  Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

It is a disassembled perspective view which shows one Embodiment of this invention containing two metal foil sheets which are substantially the same dimension. It is a perspective view which shows the other side of 1 sheet | seat among the sheets shown by FIG. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. FIG. 2 is a schematic diagram illustrating the TCN of the embodiment of FIG. 1 engaging each semiconductor device to remove heat from the semiconductor device. FIG. 2 is a schematic diagram showing a modification of the embodiment of FIG. 1. FIG. 2 is a schematic diagram illustrating a further modification of the embodiment of FIG. 1.

  As will be appreciated by one skilled in the art, the present invention may be embodied as a system or method. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely process embodiment (including design, manufacture, assembly and use steps, etc.) or a method It may take the form of an embodiment combining aspects with hardware aspects, all of which may be generally referred to herein as “processes” or “assemblies” or “systems”.

  Embodiments of the present invention provide methods and apparatus for removing heat from a semiconductor device or component, such as on a single module or complete PCB assembly. Embodiments promote simplification and reduce costs and are easily adaptable for use with multiple semiconductor components that are adjacent to each other but of different sizes or dimensions. Embodiments of the present invention can also accommodate height or other important dimensional variations that can occur between semiconductor devices of the same type.

  Referring to FIG. 1, there is shown an exploded perspective view of an embodiment of the present invention that includes a liquid flow (LFT) heat exchanger that removes heat from a plurality of semiconductor devices or components. This heat exchanger can be easily adapted for use in devices that are adjacent to each other but of different sizes. FIG. 1 shows two rectangles of substantially planar metal foil sheets 10 and 12, which are the same dimensions as useful. Therefore, the length and cross section of the sheet 10 are equal to the length and cross section of the sheet 12, respectively. Metal foil sheets 10 and 12 are formed of a material having high thermal conductivity such as copper, brass alloy, beryllium copper (BeCu), aluminum, aluminum alloy, or stainless steel. On the other hand, the present invention is not limited to them.

  Each of the sheets 10 and 12 has an inner surface, such as the inner surface 12 a of the sheet 12. The inner surface 10a of the sheet 10 is shown in FIG. Each sheet also has an outer surface, such as the outer surface 10b of the sheet 10, for example. In manufacturing the heat exchanger of FIG. 1, the sheets 10 and 12 are joined so that the inner surfaces 10a and 12a are kept in close contact with each other. As shown in FIG. 1, it is also useful to join two sheets so that the corresponding corners are aligned with each other. On the other hand, it is necessary to form certain structural or three-dimensional features in the material of at least one of the sheets before the sheets can be joined. Such structural features depend on the particular shape of the semiconductor device group in which the heat exchanger of FIG. 1 is used to remove heat.

  Still referring to FIG. 1, by way of example and not limitation, thermal contact nodes (TCNs) 14 and 16 are shown which are each formed in a metal foil sheet 10 and are therefore thermally conductive. The TCN 14 has a flat contact member 14a, and the TCN 16 has a flat contact member 16a. The member 16a protrudes from the outer surface 10b to the outside with a certain distance, and is supported with respect to the outer surface 10b by side portions 16b to 16e arranged along the four sides of the contact member 16a. As described in more detail herein below, each side includes a rigid component and an elastic component. The rigid component is firmly joined to the outer surface 10 b of the sheet 10. The elastic component is disposed between the rigid component and the member 16a, allowing the member 16a to move or bend toward or away from the outer surface 10b, in other words, to move along the Z axis. Yes.

  Similarly, the planar contact member 14a is supported so as to move along the Z-axis by the side surface portions 14b to 14e respectively disposed along the four sides of the contact member 14a. The side portions 14b to 14e have the same structure and function as the side portions 16b to 16e.

  FIG. 1 further shows that the planar contact members 14a and 16a are separated from each other by a certain distance. This means that the assembled heat exchanger of FIG. 1 is used to cool two semiconductor devices that are also spaced apart by that particular distance separating members 14a and 16a. Means. In addition, FIG. 1 shows that the contact member 16a is significantly larger than the member 14a. This means that the device where TCN 16 will be used is larger or requires a larger thermal contact surface area than the device where TCN 14 will be used.

  As described above, providing two TCNs as shown in FIG. 1 is merely an example, and the present invention is not limited to this. More generally, the number of TCNs formed on the sheet 10 and their respective sizes and locations are easily adaptable to meet the needs of many different applications that remove heat from electronic components. Emphasize. This performance highlights the flexibility afforded by embodiments of the present invention. A specifically shaped TCN designed for a particular application can be manufactured by embossing or molding sheet 10 or using other techniques known to those skilled in the art.

  In order to perform the heat removal function, it is necessary to provide a coolant fluid flow that approaches and separates each TCN and each planar contact member 14a and 16a. Thus, in addition to forming TCNs 14 and 16 in sheet 10, a coolant flow channel is also formed there. More specifically, FIG. 1 shows conduit segments 18, 20 and 22 formed in the sheet 10. Each of these segments has a semicircular cross section and is convex with respect to the outer surface 10b of the sheet 10. In other words, each segment protrudes outward from the outer surface. The conduit segment 18 extends from the conduit end 18a to the TCN 16. Segment 20 extends from TCN 16 to TCN 14, and conduit segment 22 extends from TCN 14 to conduit end 22a.

  Referring to FIG. 2, the inner surface 10a of the sheet 10, in other words, the side surface opposite to the outer surface 10b of the sheet is shown. FIG. 2 further shows that the contact member 16a of the TCN 16 and its side portions 16b-16e jointly form a chamber or compartment 24 that can receive and contain the coolant fluid. An end 18 b of the coolant conduit segment 18 is formed to access or open the chamber 24. Similarly, the end 20 a of the conduit segment 20 accesses or opens the chamber 24.

  With further reference to FIG. 2, it can be seen that, similar to TCN 16, contact member 14a and side portions 14b-14e of TCN 14 collectively form a chamber 26 that can receive and contain the coolant fluid. The end 20 b of the conduit segment 20 and the end 22 b of the conduit segment 22 each access or open the chamber 26.

  Referring again to FIG. 1, when sheets 10 and 12 are joined as described above, it can be seen that chambers 24 and 26 will be completely sealed except where they access the conduit segments. In addition, chamber 24, chamber 26, and the conduit segment together constitute a system that is sealed except for conduit ends 18a and 22a. If one of the conduit ends is used as an input port and the other as an output port, the coolant fluid selectively circulates through the conduit segment and further through chamber 24 of TCN 16 and chamber 26 of TCN 14. can do.

  When joining the metal foil sheets 10 and 12, laser welding is used to join the area around or near the TCNs 14 and 16 of the sheets 10 and 12, and also the area adjacent to the conduit segments 18-22. Can also be joined. This ensures that the chambers 24 and 26 containing the fluid and the conduit segments are tightly formed. The edges of the sheets 10 and 12 may be joined by laser welding, or may be joined by an adhesive or by a metallurgical process such as soldering.

  FIG. 1 further shows small conduit segments 28 and 30 formed in the sheet 12. Each of these conduit segments has a semicircular cross section and is convex with respect to the inner surface 12a, in other words, each conduit projects from the sheet 10, as shown in FIG. Conduit segments 28 and 30 are positioned to mate with conduit ends 18a and 22a, respectively, when sheets 10 and 12 are joined. This provides a circular opening at the mouth of each of the conduit segments 18 and 22. Couplings 32 and 34 are each tailored to the size of the corresponding opening of the opening and are attached to the corresponding opening. This coupling may then be connected to a conventional coolant fluid pump (not shown) with one of the couplings selected, for example 34, as the input port and the other as the output port. When the pump is operated, the coolant fluid circulates through each of the TCNs for heat removal applications, as described above. The coolant fluid could include distilled water or other fluids used by those skilled in the art to remove heat from the semiconductor device.

  Referring now to FIG. 3, a cross-sectional view of the metal foil sheet 10 taken along line 3-3 in FIG. 2 is shown. FIG. 3 therefore shows the features of the side portions 16e and 16c of the TCN 16. More particularly, each of these sides is shown to include a component 36 that is relatively rigid. In other words, each side component 36 is constructed such that when the TCN 16 is formed in the sheet 10, the TCN does not move relative to adjacent portions of the sheet 10.

  Still referring to FIG. 3, there is shown a component 38 attached to each rigid component 36 and also to the side or edge of the contact member 16a of the TCN 16. In forming the sheet 10, each component 38 is manufactured to bend or function as a bellows or to be flexible. Therefore, the contact member 16a can move toward and away from the sheet 10, in other words, as shown in FIG. 3, the contact member 16a can move upward or downward, that is, along the Z axis. In forming the sheet 10, the TCN elastic component 38 is usefully provided with a predetermined spring constant, allowing the elements of the TCN to compress or expand within the elastic limits of the material of the sheet 10.

  Although not shown in FIG. 3, the side portions 16b and 16d each include rigid and elastic components similar or identical to the rigid component 36 and elastic component 38, respectively.

  Still referring to FIG. 3, side portions 14e and 14c are shown that include a rigid component 40 and an elastic component 42, respectively. As described above, each component 40 is similar to component 36 and each component 42 is similar to component 38. Therefore, the contact member 14a of the TCN 14 can move along the Z axis in the same manner as the contact member 16a.

  Although not shown in FIG. 3, side portions 14b and 14d each include rigid and elastic components similar or identical to those shown in FIG. 3 in connection with side portions 14c and 14e.

  Referring to FIG. 4, a schematic diagram illustrating the use or operation of the above-described embodiment for removing heat from a semiconductor electronic device is shown. More specifically, FIG. 4 shows semiconductor devices 46 and 48 attached to PCB 44 or the like, with contact member 16a of TCN 16 being in contact with device 46. Accordingly, the heat from the device 46 is transferred to the thermally conductive member 16 a, passes through the member 16 a, and is transferred to the coolant 50 contained in the chamber 24. As described above, a coolant may be circulated through the chamber 24, so that heat is removed from the chamber.

  FIG. 4 similarly shows the contact member 14 a of the TCN 14 that contacts the semiconductor device 48 to remove heat from the semiconductor device and transfer the heat to the coolant 50 in the chamber 26. It can be seen that the semiconductor devices 46 and 48 shown in FIG. 4 are clearly different in size from each other. In view of this, TCNs 14 and 16 are similarly constructed to be different from each other so that each is matched to a corresponding semiconductor device. Accordingly, FIG. 4 further illustrates the flexibility that can be provided by embodiments of the present invention to accommodate various cooling requirements. It is contemplated that any suitable number of TCNs and conduit segments can be formed in the sheet 10 using a configuration that matches the particular arrangement of semiconductor devices.

  To illustrate further advantages provided by embodiments of the present invention, FIG. 4 shows a semiconductor device 46 with a height mark 46a. This indicia represents the height that is within the pre-specified tolerance while being the lowest height that the device 46 may have. FIG. 4 further shows that the device 46 exceeds the minimum height condition 46a by an amount Δ. However, if the TCN 16 is constructed as described above, the elastic component 38 can adjust or compensate for the aforementioned amount Δ while maintaining intimate contact with the device 46 to provide effective heat transfer. It becomes possible. As shown in FIG. 4, the member 16a is moved upward by an amount [Delta] to correspond to the height that the device 46 exceeds the minimum allowable height. At the same time, the elasticity of the components 38 prevents the device 46 or TCN 16 from being overstressed and prevents them from exceeding the elastic limit.

  In one variation of the embodiment shown in FIG. 1, one or more TCN and conduit segments may be formed in the sheet 12 with features similar to those described above with respect to the sheet 10. The resulting modified heat exchanger is then placed between two semiconductor device configurations, one of which is cooled by the TCN of the sheet 10 and the other is cooled by the TCN of the sheet 12 May be possible.

  In a further variation, it may be envisaged that the inner surfaces of both sheets 10 and 12 are covered with a metal called a barrier metal before or after forming any TCN or conduit segment. This metal does not react with the liquid used as the coolant fluid. Therefore, the use of barrier metals reduces corrosion inside the heat exchanger.

  In yet another variation, it is contemplated that the cross section of one or more conduit segments can be made larger than the cross section of other portions to increase the rate at which coolant flows out of a particular TCN. For example, the diameter of the conduit segment 18 could be larger than the diameter of the segment 22 as coolant flows from the conduit end 22a through the respective conduit segments and TCNs 14 and 16 to the conduit end 18a. . This would increase the rate at which the coolant flows out of the TCN 16 and thus increases the ability of the TCN 16 to dissipate heat. Alternatively, two or more conduit segments could be formed in the sheet 10 to carry heat away from the TCN 16.

  Referring to FIG. 5, a TCN 52 similar to TCNs 14 and 16 is shown. The TCN 52 thus includes a planar contact member 52a and side portions 52b-52e that together form a coolant chamber. In one variation of the invention, the structure 54 including a series of corrugations or undulations is formed as part of the TCN 52, in other words, integral with or in-situ with other components of the TCN 52. Accordingly, the structure 54 is housed in the coolant chamber of the TCN 52, is formed integrally with the member 52a, and is supported on the member.

  By installing the structure 54 in the coolant chamber of the TCN 52, the coolant flowing through the chamber becomes a significant turbulent flow. This turbulence also effectively dissipates heat transferred from the semiconductor device in contact with member 52a to the fluid in the chamber.

  Referring to FIG. 6, a TCN 56 similar to TCNs 14 and 16 is shown. The TCN 56 thus includes a planar contact member 56a and side portions 56b-56e that collectively form a coolant chamber. In a further modification of the invention, a structure 58 similar to the structure 54 of FIG. 5 includes a series of undulations or undulations. However, the structure 58 is formed independently of the TCN 56 and is installed in the coolant chamber of the TCN 56 after the TCN 56 is formed. Structure 58 creates coolant turbulence in the chamber of TCN 56 in a manner similar to structure 54.

  The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a, an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Further, it is to be understood that the terms “comprise” and / or “comprising”, as used herein, when used herein, describe a feature, integer value, step, Specifies the presence of an action, element or component or any combination thereof, but one or more other features, integer values, steps, actions, elements, components or groups thereof or any combination thereof It does not exclude existence or addition.

  The corresponding structures, materials, acts and equivalents of all means or step plus function elements in the following claims perform that function as specifically claimed in combination with the other claimed elements It is intended to encompass any structure, material or action. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Numerous variations and modifications will become apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments are intended to best illustrate the principles and practical applications of the present invention, as well as to various embodiments with various modifications to suit the particular application contemplated by others skilled in the art. It has been chosen and described so that the invention may be understood.

  The present invention may take the form of an entirely hardware embodiment, an entirely method embodiment or an embodiment containing both hardware and method elements. it can. In preferred embodiments, the present invention is implemented by processes that include, but are not limited to, actual components and portions and specific process steps for designing, manufacturing and utilizing the present invention.

  The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are intended to best illustrate the principles and practical applications of the present invention, as well as to various embodiments with various modifications, as will be appreciated by those skilled in the art to suit the particular application under consideration. It has been chosen and described so that the invention may be understood.

Claims (19)

A method of constructing a heat exchanger for cooling one or more semiconductor components comprising:
Providing first and second planar sheets of predetermined thermally conductive metal foil, each of the planar sheets having an inner surface and an outer surface;
Forming one or more thermal contact nodes (TCNs) on the first planar sheet, each TCN protruding outward from the outer surface of the first planar sheet, and 1 with the planar contact member; Two or more side portions, and the side portions of the at least one TCN jointly enable the contact member of the TCN to move toward and away from the outer surface of the first flat sheet. Each side of the TCN and the contact member jointly form a coolant chamber;
Configuring conduit segments along the inner surface of the first planar sheet, each conduit segment optionally between two or more of the coolant chambers of the TCN, or of the TCN. Said configuring step extending between the coolant chamber and the input or output port;
The inner surface of the second planar sheet is joined to the inner surface of the first planar sheet to form a closed flow path that includes each conduit segment and allows coolant to enter and exit the coolant chamber of each TCN. The method comprising the steps of:   The side portions of all of the TCNs each include a group of elastic components that collectively enable the contact members of the TCN to move toward and away from the outer surface of the first flat sheet. The method described.   A plurality of TCNs are formed on the first planar sheet, and each TCN has a dimension measured along a Z-axis orthogonal to the first planar sheet, and one Z-axis dimension of the TCN is the TCN. The method according to claim 1, wherein the method is different from one of the other Z-axis dimensions.   The method according to claim 1, wherein the elastic component of each of the side portions includes a bellows structure.   One or more TCNs are formed on the second planar sheet, and each TCN formed on the second planar sheet protrudes outward from the outer surface of the second planar sheet, and has one planar contact member. The method as described in any one of Claims 1-4 containing the above side part.   One or more of the conduit segments to cause the coolant to flow out of the coolant chamber of at least one of the TCNs at a rate different from that flowing out of the coolant chamber of another one of the TCNs; 6. The method according to any one of the preceding claims, wherein the cross section is made different from the cross section of one or more other conduit segments.   7. A method according to any one of the preceding claims, wherein a selected structure is installed in the given coolant chamber to produce a turbulent coolant flow through the given coolant chamber. .   The method according to claim 1, wherein the TCN and the conduit segment are formed in the first flat sheet by embossing. Said first and second planar sheet, each of each and the conduit segment of the TCN to bond a range surrounding each laser welding process is used, according to any one of claims 1-7 Method.   2. Prior to forming the TCN and configuring the conduit segment, the inner surfaces of the first and second planar sheets are each covered with a selected barrier metal that does not react with the coolant. The method as described in any one of -9.   11. The method of any one of claims 1 to 10, wherein the conduit segment and the coolant chamber jointly define a flow path for the coolant from the input port to the output port. A heat exchange device for cooling one or more semiconductor components comprising:
A first planar sheet of a predetermined thermally conductive metal foil and a second planar sheet of the predetermined thermally conductive metal foil, each of the planar sheets having an inner surface and an outer surface, and one or more thermal contact nodes (TCN) is formed on the first flat sheet, and each TCN protrudes outward from the outer surface of the first flat sheet and includes a flat contact member and one or more side portions, and at least 1 The side portions of the two TCNs each include a group of elastic components that jointly allow the contact members of the TCNs to move toward and away from the outer surface of the first flat sheet, The side portion and the contact member jointly form a coolant chamber and a conduit segment is configured along the inner surface of the first planar sheet, each conduit segment optionally including two or more of the T Between the coolant chamber of the N, or extending between the coolant chamber and the input port or output port of the TCN, said first plane sheet and the second flat sheet,
The inner surface of the second planar sheet is joined to the inner surface of the first planar sheet to form a closed flow path that includes each conduit segment and allows coolant to enter and exit the coolant chamber of each TCN. And said device.   The apparatus of claim 12, wherein the resilient component of each side includes a bellows structure.   One or more of the conduit segments to cause the coolant to flow out of the coolant chamber of at least one of the TCNs at a rate different from that flowing out of the coolant chamber of another one of the TCNs; 14. A device according to claim 12 or 13, wherein the cross section is made different from the cross section of one or more other conduit segments.   In order to increase the heat transfer efficiency of the TCN, a selected liquid flow turbulence structure is installed in the given coolant chamber to create a turbulent flow of coolant through the given coolant chamber. The device according to any one of claims 12 to 14.   The apparatus according to any one of claims 12 to 15, wherein the TCN and the conduit segment are formed in the first flat sheet by embossing.   The apparatus according to any one of claims 12 to 16, wherein the inner surfaces of the first and second planar sheets are each covered with a selected barrier metal that does not react with the coolant. An input coolant connector joined to the input port to receive coolant from the coolant circulation mechanism;
The apparatus according to claim 12, further comprising: an output coolant connector joined to the output port so as to return the coolant to the coolant circulation mechanism.   A first TCN of the TCN is in contact with a first semiconductor component, and a second TCN of the TCN is in contact with a second semiconductor component, the first and The apparatus according to any one of claims 12 to 18, wherein the second semiconductor components are adjacent to each other and each have a different height dimension.

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