Heat spreaders, electronics assemblies and methods of manufacturing electronics assemblies with improved thermal performance

Abstract

Heat spreaders, electronics assemblies having heat spreaders, and methods of manufacturing heat spreaders and electronics assemblies having improved thermal performance. One example is a heat spreader configured to be mounted to a die. The heat spreader includes a body including a top side and a bottom side, the top side arranged to face away from the die and the bottom side arranged to face toward the die. The body is shaped and adapted to be mounted to the die such that a first portion of the bottom side is thermally coupled to a first target contact location of the die, a second portion of the bottom side is thermally coupled to a second target contact location of the die, and a third portion of the bottom side is spaced from the die, thereby allowing the heat spreader to dissipate heat generated by the die.

Description

HEAT SPREADERS, ELECTRONICS ASSEMBLIES AND METHODS OF MANUFACTURING ELECTRONICS ASSEMBLIESWITH IMPROVED THERMAL PERFORMANCEFIELD OF THE DISCLOSURE

[0001] The present disclosure generally relates to cooling electronics devices, and, more particularly, to electronics assemblies and methods of manufacturing electronics assemblies with improved thermal performance.BACKGROUND

[0002] Electronics packages are used to provide protection, support, and connections for one or more electronic components therein. However, electronics packages feature one or more components, e.g., dies, that generate heat. This heat can, in turn, negatively affect the performance of the one or more electronic components, and, more generally, the electronics package itself. Accordingly, various techniques have been developed that aim to improve thermal performance by dissipating heat from the one or more heat generating components of these electronics packages.

[0003] FIG. 1 illustrates one of these techniques, whereby an electronics package in the form of a socketed CPU 100 is equipped with an integrated heat spreader 104. While difficult to see in FIG. 1 , the integrated heat spreader 104 is in thermal contact with an exposed die of the socketed CPU 100, such that heat generated by the die is transferred to the integrated heat spreader 104. This heat is then dissipated via one or more heat sinks that, while not shown in FIG. 1 , are spring loaded on the integrated heat spreader 104 in order to achieve a low thermal resistance between the integrated heat spreader 104 and the one or more heat sinks.

[0004] FIGS. 2 and 3 illustrate another one of these techniques, whereby a spring- loaded heat sink 200 is installed on an electronics package in the form of a flip chip ball grid array (FCBGA) 204 that is soldered to a printed circuit board (PCB) 208 via solder balls (not shown). In turn, the spring-loaded heat sink 200 dissipates heat generated by an exposed die 212 of the FCBGA 204.SUMMARY

[0005] In accordance with a first exemplary aspect of the present disclosure, a heat spreader is provided. The heat spreader is configured to be mounted to a die. The heat spreader includes a body including a top side and a bottom side, the top side arranged to face away from the die and the bottom side arranged to face toward the die. The body is shaped and adapted to be mounted to the die such that a first portion of the bottom side is thermally coupled to a first target contact location of the die, a second portion of the bottom side is thermally coupled to a second target contact location of the die, and a third portion of the bottom side is spaced from the die, thereby allowing the heat spreader to dissipate heat generated by the die.

[0006] In accordance with a second exemplary aspect, an electronics assembly is provided. The electronics assembly includes a die having a first target contact location and a second target contact location, the first target contact location associated with a first pre-determined internal hot spot of the die and the second target contact location associated with a second pre-determined internal hot spot of the die. The electronics assembly also includes a heat spreader shaped and mounted to the die such that a first portion of the heat spreader is thermally coupled to the first target contact location of the die and a second portion of the heat spreader is thermally coupled to the second target contact location of the die, thereby allowing the heat spreader to dissipate heat generated by the die. The electronics assembly further includes a thermal grease material that thermally couples the first portion of the heat spreader to the first target contact location of the die and the second portion of the heat spreader to the second target contact location, the thermal grease material being movable between the first and second portions of the heat spreader.

[0007] In accordance with a third exemplary aspect, a method of manufacturing an electronics assembly is provided. The method of manufacturing includes obtaining a die, identifying first and second internal hot spots of the die, and defining first and second target contact locations of the die that are associated with the first and second internal hot spots, respectively. The method of manufacturing then includes obtaining aheat spreader based on the defined first and second target contact locations. The heat spreader has a shape such that a first portion of the heat spreader is thermally coupled to the first target contact location of the die and a second portion of the heat spreader is thermally coupled to the second target contact location of the die. The method of manufacturing further includes mounting the heat spreader to the die.

[0008] In further accordance with any one or more of the foregoing first, second, or third exemplary aspects, a heat spreader, an electronics assembly, and / or a method of manufacturing an electronics assembly may include any one or more of the following further preferred forms.

[0009] In one preferred form, the first and second portions of the bottom side are offset from a central portion of the body.

[0010] In another preferred form, the bottom side has a fourth portion adapted to be thermally coupled to a third target contact location of the die.

[0011] In another preferred form, the bottom side is defined by a plurality of edges and a central portion that is recessed relative to the plurality of edges.

[0012] In another preferred form, the bottom side is defined by a first angled surface and a second angled surface, and the first portion of the bottom side is located on the first angled surface and the second portion of the bottom side is located on the second angled surface.

[0013] In another preferred form, the bottom side is partially flat.

[0014] In another preferred form, one or more flow channels are formed in the bottom side of the heat spreader.

[0015] In another preferred form, the bottom side of the heat spreader includes a first surface made of a first material and the first and second portions of the heat spreader are made of a second material that is different from the first material.

[0016] In another preferred form, the heat spreader has a third portion that is disposed between the first and second portions and is spaced from the die.

[0017] In another preferred form, the electronics assembly includes a flip chip ball grid array that includes the die.

[0018] In another preferred form, the first target location is located between the first pre-determined internal hot spot and a third pre-determined internal hot spot.

[0019] In another preferred form, the first and second portions of the heat spreader are offset from a center of the die.

[0020] In another preferred form, the die has a third target contact location associated with a third pre-determined internal hot spot of the die, and the heat spreader is shaped and mounted to the PCB such that a third portion of the heat spreader thermally contacts the third target contact location.

[0021] In another preferred form, the die has a first shape and the heat spreader has a second shape different from the first shape.

[0022] In another preferred form, the heat spreader has a top side and a bottom side, wherein the top side faces away from the die and the bottom side faces toward the die, and wherein the bottom side is defined by a plurality of edges and a central portion that is recessed relative to the plurality of edges.

[0023] In another preferred form, the heat spreader has a top side and a bottom side, wherein the top side faces away from the die and the bottom side faces toward the die, wherein the bottom side is defined by a first angled surface and a second angled surface, and wherein the first portion of the bottom side is located on the first angled surface and the second portion of the bottom side is located on the second angled surface.

[0024] In another preferred form, the heat spreader is designed based on the defined first and second target contact locations. The heat spreader may then be manufactured.

[0025] In another preferred form, the first and second internal hot spots may be identified from a thermal map produced using a thermal map of the die using a thermal camera.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 illustrates a known electronics package with an integrated heat spreader for dissipating heat generated by the electronics package.

[0027] FIG. 2 illustrates another known electronics package.

[0028] FIG. 3 illustrates a known heat sink for dissipating heat generated by the electronics package of FIG. 2.

[0029] FIG. 4 illustrates another known electronics package that is similar to the electronics package of FIG. 2 but also includes a back plate coupled thereto.

[0030] FIG. 5 illustrates another known electronics package having a die.

[0031] FIG. 6 is an exaggerated side view of the die of FIG. 5.

[0032] FIG. 7 illustrates the internal hot spots of the die of FIG. 5.

[0033] FIG. 8 is a schematic diagram of one example of a method of manufacturing an electronics assembly in accordance with the teachings of the present disclosure.

[0034] FIGS. 9A-9C illustrate one example of a stamp that can be customized and used to manufacture a heat spreader in accordance with the teachings of the present disclosure.

[0035] FIGS. 10A-10D illustrate one example of a portion of an electronics assembly constructed in accordance with the teachings of the present disclosure.

[0036] FIGS. 11 A-11 C illustrate another example of a portion of an electronics assembly constructed in accordance with the teachings of the present disclosure.

[0037] FIGS. 12A-12C illustrate another example of a portion of an electronics assembly constructed in accordance with the teachings of the present disclosure.

[0038] FIGS. 13A-13C illustrate another example of a portion of an electronics assembly constructed in accordance with the teachings of the present disclosure.

[0039] FIGS. 14A-14C illustrate another example of a portion of an electronics assembly constructed in accordance with the teachings of the present disclosure.

[0040] FIGS. 15A-15C illustrate another example of a portion of an electronics assembly constructed in accordance with the teachings of the present disclosure.

[0041] FIG. 16 illustrates another example of a portion of a heat spreader constructed in accordance with the teachings of the present disclosure.

[0042] FIG. 17 illustrates another example of a portion of a heat spreader constructed in accordance with the teachings of the present disclosure.DETAILED DESCRIPTION

[0043] One problem with the techniques discussed above is that spring-loaded heat sinks such as the spring-loaded heat sink 200 introduce forces and therefore mechanical stresses into the electronics packages and, at least in the case of the technique of FIGS. 2 and 3, into the PCB 208 and the solder balls connecting the FCBGA 204 to the PCB 208 as well. In some cases, it is necessary to install a back plate on the rear side of the PCB 208 in order to strengthen the area and reduce mechanical stresses on the solder balls, the FCBGA 204, and the PCB 208. However, even when a back plate is installed on the rear side of the PCB 208, the solder balls will eventually begin to crack in response to the mechanical stresses introduced by the spring-loaded heat sink 200. Over time, these cracks will cause the soldered connection between the FCBGA 204 and the PCB 208 to fail.

[0044] Another problem with the techniques discussed above (and other similar techniques) stems from the fact that exposed dies such as the die 212 and the die 500 illustrated in FIG. 5, which is similar to the die 212, are not flat. Indeed, the inventors of the present application have found that dies such as the die 212 and the die 500 have a convex shape, as illustrated in FIG. 6 (which exaggerates the convex nature of the die 500 for illustrative purposes). The inventors theorize that this is the result of the soldering process by which the FCBGA 204 is soldered to the PCB 208 and by which the FCBGA 600 including the die 500 is soldered to a PCB (not shown), as the die 212 and the die 500 (each made of, for example, silicone) have a different coefficient of thermal expansion than the rest of the FCBGA 204 and the FCBGA 600 (each made of, for example, FR4), respectively. As a result, the die 212 and the die 500 tend to shrink less than the rest of the FCBGA 204 and the FCBGA 600, respectively, during that soldering process, causing the dies 212 and 500 to take on that convex shape.

[0045] Because of the convex shape of the dies 212 and 500, the internal hot spots of the dies 212 and 500 tend not to be centrally (or evenly) distributed across the dies 212 and 500. In many cases, the internal hot spots of the dies 212 and 500 will be offset from a central portion of the dies 212 and 500, respectively. For example, asillustrated in FIG. 7, the die 500 has four internal hot spots 700, each of which is offset from a central portion 704 of the die 500. However, it will be appreciated that the distribution of the internal spots can vary depending upon, for example, the topology, shape, size, or material of the die.

[0046] At the same time, the spring-loaded heat sink 200 and other conventional heat spreaders (or cooling plates) are typically designed to be in thermal contact with the central portion of the die 212 (or die 500), which was previously understood to be ideal for dissipating heat. Thus, when the internal hot spots of the die are not centrally located in the die, the spring-loaded heat sink 200 and other conventional heat spreaders, while effective at dissipating heat, are not optimally designed and mounted for optimal heat dissipation.

[0047] The present disclosure aims to address these (and other) problems with conventional techniques by providing a heat spreader specifically designed based on the internal hot spots of the die and thermally coupling the heat spreader to the die at or via deterministic target contact locations on the die that are associated with the internal hot spots (and, as such, are likely to generate the most heat). In turn, by thermally coupling the heat spreader at or near the spots likely to generate the most heat, the heat spreader dissipates heat generated by the die in a more optimal manner than the spring-loaded heat sink 200 and other conventional heat spreaders.

[0048] FIG. 8 is a schematic diagram of one example of a method 800 of manufacturing an electronics assembly that includes a heat spreader constructed in accordance with the teachings of the present disclosure. In turn, the electronics assemblies (and heat spreaders) manufactured according to the method 800 offer improved thermal performance as compared to conventional electronics assemblies (and conventional heat spreaders). The method 800 is performed in the order shown and described herein, but may be implemented in or according to any number of different orders. The method or process 800 may, in other examples, include additional, fewer, or different acts.

[0049] The method 800 includes the act of obtaining a heat generating component (act 804). In this example, the heat generating component generally takes the form of an exposed die of an electronics package, e.g., the die 500 of the FCBGA 600 described above, which is in turn soldered to a PCB (e.g., the PCB 208) via solder balls. However, in other examples, the electronics package can take the form of a different type of integrated circuit package (e.g., an organic pin-grid array, a pin array cartridge, a pin-grid array, or a ceramic pin-grid array) and / or the integrated circuit package can be mounted to the PCB using a method other than soldering. In these or other examples, the heat generating component may alternatively take the form of a resistor, a cover (e.g., a plastic cover, a metal cover), or another component of the electronics package that generates heat.

[0050] In some examples, the act of obtaining the heat generating component may include manufacturing the heat generating component (or, more generally, the electronics package) using a conventional manufacturing technique and / or an additive manufacturing technique. In other examples, the act of obtaining the heat generating component may include retrieving an already manufactured heat generating component (or, more generally, an already manufactured electronics package).

[0051] The method 800 also includes the act of identifying the internal hot spots of the heat generating component (act 808). Hot spots generally exist where a lot of power is generated in a small volume. In this example, because the heat generating component takes the form of a die, the act includes identifying the internal hot spots of the die. In some examples, the internal hot spots of the die can be identified using a thermal map of the die produced using a thermal camera. In some examples, the internal hot spots of the die can be identified using documentation about the die provided by the supplier of the die. In yet other examples, the internal hot spots of the die can be identified using a simulation of the operation of the die (and, more generally, the electronics package). It will also be appreciated that the internal hot spots of the die can be identified using two or more of these methods (and / or via one or more other methods).

[0052] The method 800 further includes the act of defining target contact locations of the heat generating component (the die in this example) that are associated with the identified internal hot spots (act 812) and correspond to the locations of the heat generating component at which thermal contact with the heat spreader is desired for optimal heat dissipation. More particularly, the act of defining the target contact locations of the die generally includes defining the location and the amount (or number) of target contact locations. In some examples, the number of defined target contact locations will be equal to the number of identified internal hot spots. But in other examples, the number of defined target contact locations will be less than or greater than the number of identified internal hot spots. In some examples, some or all of the target contact locations will be located in exactly the same location as some or all of the identified internal hot spots. In other examples, some (or all) of the target contact locations will be spaced from the identified internal hot spots. In these other examples, the target contact locations may be immediately adjacent the identified internal hot spots. For example, one of the defined target contact locations may be located between two adjacent or opposing internal hot spots of the die.

[0053] The method 800 further generally includes the act of obtaining a heat spreader based on the defined target contact locations of the heat generating component (the die in this example) (act 816). More particularly, the act of obtaining the heat spreader includes obtaining a heat spreader having a size and a shape such that specific portions of the heat spreader are arranged to be thermally coupled to (i.e., in thermal contact with) the defined target contact locations, respectively, of the die while other portions of the heat spreader are spaced from the die in a manner that creates an internal cavity between the heat spreader and the die. In some examples, two target contact locations will be defined, in which case the heat spreader will have a shape such that a first portion of the heat spreader is arranged to be thermally coupled to the first target contact location of the die and a second portion of the heat spreader is arranged to be thermally coupled to the second target contact location of the die.

[0054] Preferably, the act of obtaining the heat spreader includes designing the heat spreader based on the defined target contact locations and then manufacturing the designed heat spreader. In other words, the heat spreader can be custom designed based on the defined target contact locations and then manufactured. In some examples, the desired heat spreader can be designed using three-dimensional modeling software (e.g., Computer Aided Design, or CAD, software). Once the desired heat spreader has been designed, the designed heat spreader can be manufactured using a conventional manufacturing technique and / or an additive manufacturing technique.

[0055] The conventional manufacturing technique may include techniques such as, for example, casting, milling, forging, machining, and stamping. FIGS. 9A-9C illustrate one example of a stamp 900 (as well as a frame 904 coupled to the stamp 900 and a frame 908 for heat spreader 912) that can be customized (e.g., using three-dimensional modeling software) and then used to manufacture the desired heat spreader 912. Meanwhile, the additive manufacturing technique may be any additive manufacturing technique or process that builds three-dimensional objects by adding successive layers of material on a material. The additive manufacturing technique typically involves or uses a computer, three-dimensional modeling software (e.g., Computer Aided Design, or CAD, software), machine equipment, and layering material. Once a CAD model is produced, the machine equipment may read in data from the CAD file and layer or add successive layers of liquid, powder, sheet material (for example) in a layer-upon-layer fashion to fabricate a three-dimensional object. The additive manufacturing technique may include any of several techniques or processes, such as, for example, a fused deposition modeling (“FDM”) process, a multi-jet modeling (“MJM”) process, and a selective laser sintering (“SLS”) process. In some embodiments, the additive manufacturing process may include a directed energy laser deposition process. Such a directed energy laser deposition process may be performed by a multi-axis computer- numerically-controlled (“CNC”) lathe with directed energy laser deposition capabilities.

[0056] Finally, the method 800 includes the act of mounting the obtained heat spreader to the die (act 820). The heat spreader is preferably mounted to the die by positioning the heat spreader in a desired position relative to the die and then holding the heat spreader in the desired position. The heat spreader may be positioned in the desired position and held in the desired position using any of the techniques discussed in, for example, U.S. Patent No. 11 ,114,361 , which is hereby incorporated by reference in its entirety. For example, the heat spreader may be desirably positioned and held in that position using a magnet assembly including two or more magnets, a single magnet, a single weight, one or more weights, one or more springs, or combinations thereof. However, in other examples, the heat spreader can be glued to the die or mounted to the die in a different manner. In any event, the heat spreader is mounted to the die such that the specific portions of the heat spreader are thermally coupled to the die via the target contact locations of the die (which are at or close to the internal hot spots of the die). In turn, the heat spreader is optimally positioned to dissipate heat generated by the die (and, more particularly, heat generated by the internal hot spots of the die).Moreover, because the heat spreader thermally contacts multiple portions of the die, the pressure applied by the heat spreader onto the die is distributed across a larger surface, thereby lowering any local stresses at and in the die.

[0057] At the same time, the heat spreader is mounted so that other portions of the heat spreader are spaced from the die, thereby creating the internal cavity briefly discussed above. The internal cavity allows, for example, superfluous thermal interface material applied to the die to freely move within that internal cavity toward locations where the thermal interface material is needed and / or away from locations where the thermal interface material is not needed (e.g., the portions of the heat spreader in thermal contact with the target contact locations of the die), thereby optimizing the distribution of the thermal interface material along the die.

[0058] In some examples, the method 800 may further include the act of obtaining the PCB (e.g., the PCB 204). In one example, obtaining the PCB may include manufacturing the PCB, but in another example obtaining the PCB may includeretrieving an already manufactured PCB. The PCB preferably takes the form of a 136 circuit board that includes or is formed of any number of electronics components known in the art. In other examples, however, the PCB may take the form of a different circuit board. In some examples, the method 800 may further include the act of mounting the electronics package (which includes the die) to the PCB. In one example, the electronics package is mounted to the PCB by soldering (e.g., using a surface mount soldering process, a wave soldering processor any other known soldering process).

[0059] In some examples, the method 800 may further include measuring the shape of the heat generating component. When the heat generating component is a die, the measuring includes measuring the convex shape of the die. In some examples, the method 800 further includes generating a three-dimensional model of the heat generating component that represents the measured shape of the heat generating component. In some examples, the act of defining the target contact locations and / or the act of obtaining the heat spreader can be based on the generated three-dimensional model. In one example, the three-dimensional model can be used to define the tangent for each target contact location and the heat spreader can be designed in accordance with those tangential surfaces. For example, when two target contact locations are defined, the heat spreader can be designed so that a first portion of the heat spreader has a tangential contact with the first target contact location and a second surface of the heat spreader has a tangential contact with the second target contact location.

[0060] In some examples, the method 800 may further include, prior to mounting the heat spreader to the heat generating component, applying a thermal interface material (e.g., thermal grease) to the heat generating component. In turn, when the heat spreader is mounted to the heat generating component, the thermal interface material is disposed between the heat generating component and the heat spreader. Preferably, the thermal interface material should be applied so that at least some of the thermal interface material is located at or close to the target contact locations of the die.

[0061] In some examples, the method 800 may further include, prior to mounting the heat spreader to the heat generating component, modifying part or all of the surface(s)of the designed heat spreader in order to enhance the thermal connection between the heat spreader and the heat generating component. For example, part or all of the surface(s) of the designed heat spreader may be modified by brushing or polishing some or all of the surface(s), finishing part or all of the surface(s), structuring (e.g., laser structuring) some or all of the surface(s), or combinations thereof.

[0062] It will be appreciated that one or more of any of the foregoing acts of the method 800 may be partially or entirely performed using a controller 850. The controller 850 may, for example, cause a thermal camera to perform a thermal scan of the die, produce a thermal map from that thermal scan, and identify the internal hot spots of the die using the produced thermal map. The controller 850 may, as another example, define the target contact locations of the die based on the identified internal hot spots. The controller 850 may, as a further example, design the heat spreader to be manufactured and / or facilitate the manufacture of the heat spreader.

[0063] The method 800 described herein can be used to provide heat spreaders of all shapes and sizes for optimally dissipating heat generated by dies (or other heat generating components) of different shapes and sizes. Generally speaking, the provided heat spreaders will have one or more portions that specifically match the shape and size of the die(s). More particularly, the provided heat spreaders will have a body that includes a top side and a bottom side, the top side arranged to face away from the die and the bottom side arranged to face toward the die and including two or more portions shaped and adapted to be thermally coupled to two or more defined target contact locations of the die, respectively. In some examples, the bottom side of the provided heat spreader may be at least partially defined by a plurality of edges and a central portion that is recessed relative to the plurality of edges. In some examples, the bottom side of the provided heat spreader may be partially flat, while in other examples the bottom side of the provided heat spreader may be entirely curved. In some examples, the bottom side of the provided heat spreader may be at least partially defined by one or more angled surfaces that are not parallel to the PCB and / or not parallel to the top surface of the die. In some examples, the bottom side of the providedheat spreader may be at least partially defined by two or more angled surfaces. In one example, the two or more angled surfaces are not co-planar with one another. In one example, some or all of the angled surfaces may contact the die at a different target contact location. In other words, some or all of the angled surfaces may carry one or more of the portions shaped and adapted to be thermally coupled to the defined target contact locations. In this example, one or more internal cavities may be formed between the different target contact locations by gaps where the surfaces do not contact the top surface of the die.

[0064] FIGS. 10A-10D illustrate one example of a portion of an electronics assembly 1000 that can be produced using the method 800 (or a different method constructed in accordance with the teachings of the present disclosure). The electronics assembly 1000 generally includes an exposed silicon die 1004 and a heat spreader 1008 designed to be thermally coupled to, and to optimally dissipate heat generated by, the die 1000. While not illustrated herein, it will be appreciated that the exposed die 1004 is part of an electronics package such as a flip chip ball grid array that is in turn mounted to a PCB. Thus, it will be appreciated that FIGS. 10A-10D only illustrate a portion of the heat spreader 1008, which will typically be larger (and sometimes significantly larger) than the exposed silicon die 1004.

[0065] As illustrated in FIG. 10A, the exposed die 1004 has four perimeter edges 1010 and four internal hot spots 1012 within those perimeter edges 1010, each of which is offset from a central portion 1016 of the die 1004. The four internal hot spots 1012 may, for example, be identified using a thermal map of the die 1008 or documentation about the die 1004 provided by the supplier. Based on the internal hot spots 1012, two target contact locations 1020A, 1020B are defined. The two target contact locations 1020A, 1020B are also offset from the central portion 1016 of the die 1004, with the first target contact location 1020A generally located between the upper two internal hot spots 1012 and the second target contact location 1020B generally located between the lower two internal hot spots 1012. Thus, the first target contact location 1020A isassociated with the upper two internal hot spots 1012 and the second target contact location 1020B is associated with the lower two internal hot spots 1012.

[0066] The heat spreader 1008 is specifically designed based on the defined target contact locations 1020A, 1020B of the die 1004. More particularly, the heat spreader 1008 is specifically designed (e.g., shaped and sized) so that first and second portions 1024A, 1024B of the heat spreader 1008 are thermally coupled to the target contact locations 1020A, 1020B of the die 1008, respectively, either directly or via a thermal interface material 1026 disposed therebetween, when the heat spreader 1008 is mounted to the die 1004.

[0067] As illustrated in FIG. 10B, the heat spreader 1008 in this example has a body (only a portion of which is visible) that has a top side 1028 and a bottom side 1032 that is opposite the top side 1028 and includes the first and second portions 1024A, 1024B. The portion of the top side 1028 visible in FIG. 10B is substantially if not entirely flat. However, the portion of the bottom side 1032 visible in FIG. 10B has a substantially triangular shape that is defined by a first edge 1036, a second edge 1040 opposite the first edge 1036, a first angled surface 1044 that extends inward from the first edge 1036, and a second angled surface 1048 that extends inward from the second edge 1040 toward the first edge 1036. The second angled surface 1048 meets the first angled surface 1044 at a central portion 1052 that is in turn recessed relative to the first and second edges 1036, 1040.

[0068] After the thermal interface material 1026 is applied to the die 1004, the heat spreader 1008 is mounted to the die 1004 so that the first and second edges 1036, 1040 of the bottom side 1032 of the heat spreader 1008 are substantially aligned with two of the edges 1010 of the die 1004, as illustrated in FIG. 10C. In turn, the first portion 1024A of the heat spreader 1008 is thermally coupled to the first target contact location 1020A via the thermal interface material 1026, and the second portion 1024B of the heat spreader 1008 is thermally coupled to the second target contact location 1020B (also via the thermal interface material 1026), as illustrated in both FIGS. 10C and 10D. At the same time, multiple portions of the heat spreader 1008, including the centralportion 1052 (which is located between the first and second portions 1024A, 1024B), are spaced from the die 1004. As a result, one or more internal cavities 1056 are created between the bottom side 1032 of the heat spreader 1008 and the die 1004. In this example, three such cavities 1056 are created, one immediately adjacent the first edge 1036, one immediately adjacent the second edge 1040, and one below the central portion 1052.

[0069] In operation, the heat spreader 1008 dissipates heat generated by the die 1004. More particularly, heat spreader 1008 is optimally positioned and mounted to the die 1004 so as to dissipate heat generated by the internal hot spots 1012 of the die 1004. This is accomplished by way of the thermal coupling between the first and second portions 1024A, 1024B of the heat spreader 1008 and the first and second target contact locations 1020A, 1020B, respectively, of the die 1004. Optimal heat dissipation is facilitated by the internal cavities 1056, which allow the thermal interface material 1026 to freely move within the internal cavities 1056, such that superfluous thermal interface material is movable towards location where the thermal interface material is needed (e.g., beneath the central portion 1052) and / or away from locations where the thermal interface material is not needed (e.g., the first and second portions 1024A, 1024B).

[0070] FIGS. 11 A-11 C illustrate another example of a portion of an electronics assembly 1 100 that can be produced using the method 800 (or a different method constructed in accordance with the teachings of the present disclosure). The electronics assembly 1 100 is structurally and functionally similar to the electronics assembly 1000 but is different in several ways.

[0071] First, unlike the exposed die 1004, the electronics assembly 1100 has an exposed die 1104 having three internal hot spots 1112. Based on those internal hot spots 1112, three target contact locations 1120A, 1 120B, 1120C are defined. Like the target contact locations 1020A, 1020B, the target contact locations 1120A, 1120B, 1 120C are offset from a central portion of the die 1104, but the target contact locations 1 120A, 1120B, 1120C are aligned with the three internal hot spots 11 12, respectively.

[0072] Second, as a result of the differences between the internal hot spots 1012 and the internal hot spots 1 1 12 and the target contact locations 1020A, 1020B and 1120A, 1 120B, 1120C, the electronics assembly 1 100 has a heat spreader 1 108 that is different from the heat spreader 1008. More particularly, the heat spreader 1108 (only a portion of which is visible in FIGS. 11 B and 1 1 C) is specifically designed (e.g., shaped and sized) so that first, second, and third portions 1124A, 1 124B, 1 124C of the heat spreader 1108 are thermally coupled to the target contact locations 1 120A, 1120B, 1 120C, respectively, either directly or via a thermal interface material (not shown) disposed therebetween, when the heat spreader 1108 is mounted to the die 1 104.

[0073] Third, and to this end, the heat spreader 1108 has a bottom side 1 132 that has a different shape than the bottom side 1032 of the heat spreader 1008. The portion of the bottom side 1 132 illustrated in FIG. 11 B is defined by a first edge 1136, a second edge 1140 opposite the first edge 1136, a first angled surface 1144 that extends inward from the first edge 1136, a second angled surface 1148 that extends inward from the first angled surface 1 144, and a third angled surface 1 150 arranged between the second edge 1 140 and the second angled surface 1 148.

[0074] After the thermal interface material is applied to the die 1104, the heat spreader 1108 is mounted to the die 1104 so that the first and second edges 1136, 1 140 of the bottom side 1132 of the heat spreader 1 108 are substantially aligned with two of the edges 11 10 of the die 1104, as illustrated in FIG. 1 1 C. In turn, the first portion 1124A of the heat spreader 1108 is thermally coupled to the first target contact location 1 120A via the thermal interface material, the second portion 1124B of the heat spreader 1108 is thermally coupled to the second target contact location 1 120B (also via the thermal interface material, and the third portion 1 124C of the heat spreader 1108 is thermally coupled to the third target contact location 1 120C (also via the thermal interface material) as illustrated in FIG. 11 C. At the same time, and like the electronics assembly 1000, multiple portions of the heat spreader 1 108 are spaced from the die 1 104. As a result, one or more internal cavities are created between the bottom side 1 132 of the heat spreader 1 108 and the die 1104.

[0075] In operation, the heat spreader 1 108 dissipates heat generated by the die 1 104. More particularly, heat spreader 1 108 is optimally positioned and mounted to the die 1104 so as to dissipate heat generated by the internal hot spots 1 1 12 of the die 1 104. This is accomplished by way of the thermal coupling between the first, second, and third portions 1 124A, 1124B, and 1 124C of the heat spreader 1 108 and the first, second, and third target contact locations 1120A, 1 120B, and 1120C, respectively, of the die 1104. Optimal heat dissipation is facilitated by the internal cavities, which allow the thermal interface material to freely move within the internal cavities, such that superfluous thermal interface material is movable towards location where the thermal interface material is needed and / or away from locations where the thermal interface material is not needed (e.g., the first, second, and third portions 1 124A, 1124B, and 1 124C).

[0076] FIGS. 12A-12C illustrate another example of a portion of an electronics assembly 1200 that can be produced using the method 800 (or a different method constructed in accordance with the teachings of the present disclosure). The electronics assembly 1200 is structurally and functionally similar to the electronics assembly 1000 but is different in several ways.

[0077] First, like the exposed die 1004, the electronics assembly 1200 has an exposed die 1204 having four internal hot spots 1212, but the internal hot spots 1212 are located in a different location than the internal hot spots 1012 of the exposed die 1004. Based on those internal hot spots 1212, four target contact locations 1220A, 1220B, 1220C, and 1220D are defined. Like the target contact locations 1020A, 1020B, the target contact locations 1220A, 1220B, 1220C, 1220D are offset from a central portion of the die 1204, but the target contact locations 1220A, 1220B, 1220C, and 1220D are aligned with the four internal hot spots 1212, respectively.

[0078] Second, as a result of the differences between the internal hot spots 1212 and the internal hot spots 1012 and the target contact locations 1020A, 1020B and 1220A- 1 120D, the electronics assembly 1200 has a heat spreader 1208 that is different from the heat spreader 1008. More particularly, the heat spreader 1208 (only a portion ofwhich is visible in FIGS. 12B and 12C) is specifically designed (e.g., shaped and sized) so that first, second, third, and fourth portions 1224A, 1224B, 1224C, and 1224D of the heat spreader 1208 are thermally coupled to the target contact locations 1220A, 1220B, 1220C, and 1220D, respectively, either directly or via a thermal interface material (not shown) disposed therebetween, when the heat spreader 1208 is mounted to the die 1204.

[0079] Third, and to this end, the heat spreader 1208 has a bottom side 1232 that has a different shape than the bottom side 1032 of the heat spreader 1008. Indeed, the portion of the bottom side 1232 illustrated in FIG. 12B is defined by a first edge 1236, a second edge 1240 opposite the first edge 1236, a third edge 1241 , a fourth edge 1242 opposite the third edge 1241 , and four angled surfaces that extend inward from the four edges 1236, 1240, 1241 , and 1242 and meet at a recessed central portion 1252.

[0080] After the thermal interface material is applied to the die 1204, the heat spreader 1208 is mounted to the die 1204 so that the edges 1236, 1240, 1241 , 1242 of the bottom side 1232 of the heat spreader 1208 are substantially aligned with the edges 1210 of the die 1204, as illustrated in FIG. 12C. In turn, the first portion 1224A of the heat spreader 1208 is thermally coupled to the first target contact location 1220A via the thermal interface material, the second portion 1224B of the heat spreader 1208 is thermally coupled to the second target contact location 1220B (also via the thermal interface material, the third portion 1224C of the heat spreader 1208 is thermally coupled to the third target contact location 1220C (also via the thermal interface material), and the fourth portion 1224D of the heat spreader 1208 is thermally coupled to the fourth target contact location 1220D, as illustrated in FIG. 12C. At the same time, and like the electronics assembly 1000, multiple portions of the heat spreader 1208 are spaced from the die 1204. As a result, one or more internal cavities are created between the bottom side 1232 of the heat spreader 1208 and the die 1204.

[0081] In operation, the heat spreader 1208 dissipates heat generated by the die 1204. More particularly, heat spreader 1208 is optimally positioned and mounted to the die 1204 so as to dissipate heat generated by the internal hot spots 1212 of the die1204. This is accomplished by way of the thermal coupling between the first, second. Third, and fourth portions 1224A, 1224B, 1224C, and 1224D of the heat spreader 1208 and the first, second, third, and fourth target contact locations 1220A, 1220B, 1220C, and 1220D, respectively, of the die 1204. Optimal heat dissipation is facilitated by the internal cavities, which allow the thermal interface material to freely move within the internal cavities, such that superfluous thermal interface material is movable towards location where the thermal interface material is needed and / or away from locations where the thermal interface material is not needed (e.g., the first, second, third, and fourth portions 1224A, 1224B, 1224C, and 1224D).

[0082] FIGS. 13A-13C illustrate another example of a portion of an electronics assembly 1300 that can be produced using the method 800 (or a different method constructed in accordance with the teachings of the present disclosure). The electronics assembly 1300 is structurally and functionally similar to the electronics assembly 1000 but is different in several ways.

[0083] First, unlike the exposed die 1004, the electronics assembly 1300 has an exposed die 1304 having two internal hot spots 1312. Based on those internal hot spots 1312, two target contact locations 1320A and 1320B are defined. Like the target contact locations 1020A, 1020B, the target contact locations 1320A and 1320B are offset from a central portion of the die 1304, but the target contact locations 1320A and 1320B are aligned with the two internal hot spots 1312, respectively.

[0084] Second, as a result of the differences between the internal hot spots 1312 and the internal hot spots 1012 and the target contact locations 1020A, 1020B and 1320A and 1320B, the electronics assembly 1300 has a heat spreader 1308 that is different from the heat spreader 1008. More particularly, the heat spreader 1308 (only a portion of which is visible in FIGS. 13B and 13C) is specifically designed (e.g., shaped and sized) so that first and second portions 1324A and 1324B of the heat spreader 1308 are thermally coupled to the target contact locations 1320A and 1320B, respectively, either directly or via a thermal interface material (not shown) disposed therebetween, when the heat spreader 1308 is mounted to the die 1304.

[0085] Third, and to this end, the heat spreader 1308 has a bottom side 1332 that has a different shape than the bottom side 1032 of the heat spreader 1008. The portion of the bottom side 1332 illustrated in FIG. 13B is defined by a first edge 1336, a second edge 1340 opposite the first edge 1336, a third edge 1341 , a fourth edge 1342 opposite the third edge 1341 , two flat surfaces, and two angled surfaces that extend inward from the two flat surfaces and meet at a central portion 1352.

[0086] After the thermal interface material is applied to the die 1304, the heat spreader 1308 is mounted to the die 1304 so that the edges 1336, 1340, 1341 , 1342 of the bottom side 1332 of the heat spreader 1308 are substantially aligned with the edges 1310 of the die 1304, as illustrated in FIG. 13C. In turn, the first portion 1324A of the heat spreader 1308 is thermally coupled to the first target contact location 1320A via the thermal interface material, and the second portion 1324B of the heat spreader 1308 is thermally coupled to the second target contact location 1320B (also via the thermal interface material. At the same time, and like the electronics assembly 1000, multiple portions of the heat spreader 1308 are spaced from the die 1304. As a result, one or more internal cavities are created between the bottom side 1332 of the heat spreader 1308 and the die 1304.

[0087] In operation, the heat spreader 1308 dissipates heat generated by the die 1304. More particularly, heat spreader 1308 is optimally positioned and mounted to the die 1304 so as to dissipate heat generated by the internal hot spots 1312 of the die 1304. This is accomplished by way of the thermal coupling between the first and second portions 1324A and 1324B of the heat spreader 1308 and the first and second target contact locations 1320A and 1320D, respectively, of the die 1304. Optimal heat dissipation is facilitated by the internal cavities, which allow the thermal interface material to freely move within the internal cavities, such that superfluous thermal interface material is movable towards location where the thermal interface material is needed and / or away from locations where the thermal interface material is not needed.

[0088] FIGS. 14A-14C and 15A-15C illustrate portions of other examples of electronic assemblies 1400, 1500, respectively, that can be produced using the method800 (or a different method constructed in accordance with the teachings of the present disclosure). The electronic assemblies 1400, 1500 are structurally similar to the electronics assembly 1000. However, because the electronics assemblies 1400, 1500 have exposed dies 1404, 1504, respectively, that have different internal hot spots, the electronics assemblies 1400, 1500 have different target contact locations 1420, 1520, respectively, and different heat spreaders 1408, 1508, respectively, designed to be thermally coupled to those different target contact locations 1420, 1520, respectively. Nonetheless, despite these differences, the heat spreaders 1408, 1508 (only a portion of which is visible in FIGS. 14B, 14C and FIGS. 15B, 15C) dissipate heat generated by the dies 1404, 1504, respectively, in a similar manner as the other heat spreaders described above.

[0089] FIG. 16 illustrates one example of a portion of a heat spreader 1608 that can be utilized in any of the electronic assemblies described herein (or other electronic assemblies constructed in accordance with the teachings of the present disclosure). The heat spreader 1608 is similar to the heat spreader 1408, but the portion of the heat spreader 1608 visible in FIG. 16 also includes one or more flow channels formed in a bottom side 1632 of the heat spreader 1608. In this example, the heat spreader 1608 includes a plurality of flow channels 1660 formed in the bottom side 1632 of the heat spreader 1608. The plurality of flow channels 1660 are formed in the angled surfaces of the bottom side 1632 of the heat spreader 1608, though in other examples, the plurality of flow channels 1660 can be formed in a different manner. In any event, the plurality of flow channels 1660 help to facilitate movement of the thermal interface material between the heat spreader 1608 and the heat generating component to which the heat spreader 1608 is mounted.

[0090] FIG. 17 illustrates another example of a portion of a heat spreader 1708 that can be utilized in any of the electronics assemblies described herein (or other electronic assemblies constructed in accordance with the teachings of the present disclosure). The heat spreader 1708 is similar to the heat spreader 1408, but the portion of the heat spreader 1708 visible in FIG. 17 includes one or more portions made of a differentmaterial than the rest of the heat spreader 1708. In this example, the heat spreader 1708 includes four portions 1724 that are made of a second material that is different from a first material from which the rest of the heat spreader 1708 is made, and those four portions 1724 are the portions of the heat spreader 1708 configured to be thermally coupled to the four target contact locations, respectively, of the heat generating component to which the heat spreader 1708 is mounted. In this example, the second material has a greater surface roughness than the first material, such that the four portions 1724 are rougher than the rest of the heat spreader 1708, which may facilitate better heat dissipation from the four target contact locations thermally coupled thereto. In other examples, however, the second material can have a surface roughness that is less than the first material.

[0091] The heat spreaders described herein are preferably made of a sheet metal with a higher thermal conductivity, such as, for example, copper, steel, nickel, tin, or a metal alloy. In some cases, the heat spreaders described herein can be brushed or polished. In some cases, the heat spreaders described herein can be partially or entirely surface treated with a surface material (e.g., gold, nickel, or tin) that is compatible with the metallic material of the rest of the heat spreader, can be soldered, and also is thermally conductive. For example, the heat spreader can be made of copper and, as discussed above, a portion or all of the heat spreader can be finished with a nickel and gold plate. And in some cases, the heat spreaders described herein can be partially or entirely structured (e.g., laser structured) or subjected to another type of post-manufacturing process.

[0092] It will also be appreciated that the electronics assemblies described herein typically include a heat sink (e.g., a spring-loaded heat sink). The heat sink is thermally coupled to the respective heat spreader in order to facilitate dissipation of the heat generated by the heat generating component (e.g., the die) and transferred to the heat spreader. In some examples, the heat sink is thermally coupled to the heat spreader via a thermal material, e.g., a thermal grease, a thermal paste, or a thermal pad, disposed between the heat sink and the heat spreader.

[0093] Preferred embodiments of this invention are described herein, including the best mode or modes known to the inventors for carrying out the invention. Although numerous examples are shown and described herein, those of skill in the art will readily understand that details of the various embodiments need not be mutually exclusive. Instead, those of skill in the art upon reading the teachings herein should be able to combine one or more features of one embodiment with one or more features of the remaining embodiments. Further, it also should be understood that the illustrated embodiments are exemplary only and should not be taken as limiting the scope of the invention. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the aspects of the exemplary embodiment or embodiments of the invention, and do not pose a limitation on the scope of the invention. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Claims

CLAIMS1 . A heat spreader configured to be mounted to a die, the heat spreader comprising: a body comprising a top side and a bottom side, the top side arranged to face away from the die and the bottom side arranged to face toward the die, wherein the body is shaped and adapted to be mounted to the die such that a first portion of the bottom side is thermally coupled to a first target contact location of the die, a second portion of the bottom side is thermally coupled to a second target contact location of the die, and a third portion of the bottom side is spaced from the die, thereby allowing the heat spreader to dissipate heat generated by the die.

2. The heat spreader of claim 1 , wherein the first and second portions of the bottom side are offset from a central portion of the body.

3. The heat spreader of claim 1 , wherein the bottom side has a fourth portion adapted to be thermally coupled to a third target contact location of the die.

4. The heat spreader of claim 1 , wherein the bottom side is defined by a plurality of edges and a central portion that is recessed relative to the plurality of edges.

5. The heat spreader of claim 1 , wherein the bottom side is defined by a first angled surface and a second angled surface, and wherein the first portion of the bottom side is located on the first angled surface and the second portion of the bottom side is located on the second angled surface.

6. The heat spreader of claim 1 , wherein the bottom side is partially flat.

7. The heat spreader of claim 1 , further comprising one or more flow channels formed in the bottom side of the heat spreader.

8. The electronics assembly of claim 1 , wherein the bottom side of the heat spreader comprises a first surface made of a first material and the first and second portions of the heat spreader are made of a second material that is different from the first material.

9. An electronics assembly, comprising: a die having a first target contact location and a second target contact location, the first target contact location associated with a first pre-determined internal hot spot of the die and the second target contact location associated with a second pre-determined internal hot spot of the die; a heat spreader shaped and mounted to the die such that a first portion of the heat spreader is thermally coupled to the first target contact location of the die and a second portion of the heat spreader is thermally coupled to the second target contact location of the die, thereby allowing the heat spreader to dissipate heat generated by the die; and a thermal grease material that thermally couples the first portion of the heat spreader to the first target contact location of the die and the second portion of the heat spreader to the second target contact location, wherein the thermal grease material is movable between the first and second portions of the heat spreader.

10. The electronics assembly of claim 9, wherein the heat spreader has a third portion that is disposed between the first and second portions and is spaced from the die.1 1 . The electronics assembly of claim 9, further comprising a flip chip ball grid array (FCBGA) comprising the die.

12. The electronics assembly of claim 9, wherein the first target location is located between the first pre-determined internal hot spot and a third pre-determined internal hot spot.

13. The electronics assembly of claim 9, wherein the first and second portions of the heat spreader are offset from a center of the die.

14. The electronics assembly of claim 9, wherein the die has a third target contact location associated with a third pre-determined internal hot spot of the die, and wherein the heat spreader is shaped and mounted to the die such that a third portion of the heat spreader thermally contacts the third target contact location.

15. The electronics assembly of claim 9, wherein the die has a first shape and the heat spreader has a second shape different from the first shape.

16. The electronics assembly of claim 9, wherein the heat spreader has a top side and a bottom side, wherein the top side faces away from the die and the bottom side faces toward the die, and wherein the bottom side is defined by a plurality of edges and a central portion that is recessed relative to the plurality of edges.

17. The electronics assembly of claim 9, wherein the heat spreader has a top side and a bottom side, wherein the top side faces away from the die and the bottom side faces toward the die, wherein the bottom side is defined by a first angled surface and a second angled surface, and wherein the first portion of the bottom side is located on the first angled surface and the second portion of the bottom side is located on the second angled surface.

18. A method of manufacturing an electronics assembly, comprising: obtaining a die; identifying first and second internal hot spots of the die; defining first and second target contact locations of the die that are associated with the first and second internal hot spots, respectively; obtaining a heat spreader based on the defined first and second target contact locations, the heat spreader having a shape such that a first portion of the heat spreader is thermally coupled to the first target contact location of the die and a second portion of the heat spreader is thermally coupled to the second target contact location of the die; and mounting the heat spreader to the die.

19. The method of manufacturing of claim 18, wherein the act of obtaining the heat spreader comprises: designing the heat spreader based on the defined first and second target contact locations; and manufacturing the designed heat spreader.

20. The method of manufacturing of claim 18, further comprising producing a thermal map of the die using a thermal camera, wherein the first and second internal hot spots are identified from the produced thermal map.

Images