Systems and methods for interlock features on power modules

Abstract

A system includes a power module, wherein the power module includes a first interlock feature on a first surface of the power module; and at least one heat sink, where the at least one heat sink includes a second interlocking feature on a surface of the at least one heat sink, where the surface of the at least one heat sink includes a layer of thermal interface material.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. non-provisional patent application No. 18 / 159,427 filed on January 25, 2023, which claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 377,486 filed on September 28, 2022, U.S. Provisional Patent Application No. 63 / 377,501 filed on September 28, 2022, U.S. Provisional Patent Application No. 63 / 377,512 filed on September 28, 2022, and U.S. Provisional Patent Application No. 63 / 378,601 filed on October 6, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Various embodiments of the present disclosure relate generally to power modules, and more particularly to systems and methods for providing bond wire thickness (BLT) control and interlocking features on a power module to, for example, facilitate alignment of the power module with one or more heat sinks during an assembly process. Background Art

[0004] The power module is one of the key components in the traction inverter for controlling the performance and / or efficiency of the drive system. The key aspects for performance and reliability come from the correct bond wire thickness control of the TIM (thermal interface material) and from the correct placement of the power module on the heat sink in a way that a strong bond integrity is formed between the power module and the heat sink. Summary of the invention

[0005] In some aspects, the technology described herein relates to a system comprising: a power module, wherein the power module includes a first interlocking feature on a first surface of the power module; and at least one heat sink, wherein the at least one heat sink includes a second interlocking feature on a surface of the at least one heat sink, wherein the surface of the at least one heat sink includes a thermal interface material layer.

[0006] In some aspects, the technology described herein relates to a system wherein a power module includes a first interlocking feature on a second surface of the power module, wherein the second surface is separated from the first surface by a width of the power module.

[0007] In some aspects, the technology described herein relates to a system wherein the first interlocking feature is a protruding interlocking feature.

[0008] In some aspects, the technology described herein relates to a system wherein the second interlocking feature is a recessed interlocking feature.

[0009] In some aspects, the technology described herein relates to a system wherein the recessed interlocking feature is a blind cavity.

[0010] In some aspects, the technology described herein relates to a system wherein the thermal interface material layer includes thermally conductive tape, gel, thermally conductive epoxy, solder, grease, gap filler pads, and phase change material.

[0011] In some aspects, the technology described herein relates to a system wherein the first surface and the second surface include an epoxy molding compound or a copper layer.

[0012] In some aspects, the technology described herein relates to a system wherein the first interlocking feature is located on an epoxy molding compound or a copper layer.

[0013] In some aspects, the technology described herein relates to a system wherein the at least one heat sink includes an inlet port or an outlet port.

[0014] In some aspects, the technology described herein relates to a system in which a layer of thermal interface material extends uniformly across a surface between recessed interlocking features of the at least one heat spreader.

[0015] In some aspects, the technology described herein relates to a method for aligning a power module and a heat sink, the method comprising: forming a first interlocking feature on a surface of the power module; forming a second interlocking feature on a surface of the heat sink; applying a layer of thermal interface material on a surface of the heat sink or the power module; and mating the first interlocking feature with the second interlocking feature.

[0016] In some aspects, the technology described herein relates to a method wherein forming the second interlocking feature includes machining or laser drilling into a surface of the heat sink.

[0017] In some aspects, the technology described herein is directed to a method wherein the first interlocking feature is a protruding interlocking feature.

[0018] In some aspects, the technology described herein is directed to a method wherein the second interlocking feature is a recessed interlocking feature.

[0019] In some aspects, the technology described herein relates to a method in which a layer of thermal interface material is uniformly applied to a surface between recessed interlocking features of a heat sink.

[0020] In some aspects, the technology described herein relates to a method further comprising: performing a finite element analysis to determine ideal positions for both the first interlocking feature and the second interlocking feature.

[0021] In some aspects, the technology described herein relates to a method wherein applying a thermal interface material layer includes dispensing the thermal interface material layer onto a surface of a heat sink or a power module using a solder paste, a silver sintering paste, or a pump.

[0022] In some aspects, the technology described herein relates to a method in which applying a layer of thermal interface material comprises any suitable pattern, such as dots, serpentines, or spirals.

[0023] In some aspects, the technology described herein relates to a method further comprising aligning a heat sink with a power module.

[0024] In some aspects, the technology described herein relates to a method in which a heat sink and a power module are aligned by a deformable washer or a spring clamp.

[0025] Other objects and advantages of the disclosed embodiments will be described in part in the following description, and in part will be obvious from the description, or can be understood by practicing the disclosed embodiments. The objects and advantages of the disclosed embodiments will be realized and achieved by means of the elements and combinations particularly pointed out in the appended claims.

[0026] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed embodiments, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments.

[0028] Figure 1 An exemplary system infrastructure for a vehicle including a traction inverter is depicted according to one or more embodiments.

[0029] Figure 2A and Figure 2B Depicted is a side view of an exemplary system of interlocking features on a power module and heat sink according to an embodiment of the present disclosure.

[0030] Figure 3A and Figure 3B Another embodiment of an exemplary system of interlocking features on a power module and a heat sink is depicted.

[0031] Figure 4A and Figure 4B Another embodiment of an exemplary system of interlocking features on a power module and a heat sink is depicted.

[0032] Figure 5A and Figure 5B Another embodiment of an exemplary system of interlocking features on a power module and a heat sink is depicted.

[0033] Figure 6 An exemplary method for aligning interlocking features on a heat sink with interlocking features on a power module is depicted. DETAILED DESCRIPTION

[0034] Both the foregoing general description and the following detailed description are exemplary and explanatory only and do not constrain the claimed features. As used herein, the terms "comprises," "comprising," "has," "having," "includes," "including," or other variations thereof are intended to encompass non-exclusive inclusions such that a process, method, article, or device that includes a series of elements includes not only those elements, but may also include other elements that are not explicitly listed or inherent to such process, method, article, or device. In the present disclosure, unless otherwise stated, relative terms (such as, for example, "about," "substantially," and "approximately") are used to indicate possible ±10% variations in the stated values. In the present disclosure, unless otherwise stated, any numerical value may include possible ±10% variations in the stated values.

[0035] The terms used below may be interpreted in their broadest reasonable manner, although they are being used in conjunction with a detailed description of certain specific examples of the present disclosure. Indeed, certain terms may even be emphasized below; however, any term intended to be interpreted in any constrained manner will be explicitly and specifically defined as such in this detailed description. For example, in the context of the present disclosure, a power module may be described as a device, but may refer to any device used to control power flow in a circuit. For example, a power module may be, for example, a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT) or a relay, or any combination thereof, but is not limited thereto.

[0036] As described herein, interlocking features on a power module and / or heat sink can eliminate the tools required to ensure proper placement of the power module on the heat sink during package assembly. In addition, the interlocking features can provide an increase in the strength of the bond integrity between the power module and the heat sink. The increase in strength provided by the interlocking features can reduce failures or cracks on the power module by forming a strong interlocking bond and tight control of the bond wire thickness.

[0037] Now turn to Figure 1, depicts an exemplary system infrastructure for a vehicle including a traction inverter 102 according to one or more embodiments of the present disclosure. The electric vehicle 100 may include a traction inverter 102, a drive motor 106, a battery 110, and a connector 104 connecting the inverter 102 and the battery 110. The traction inverter 102 may include components for receiving electric power from an external source and outputting electric power to charge the battery 110 of the electric vehicle 100. For example, the traction inverter 102 may convert DC power from the battery 110 in the electric vehicle 100 into AC power by using a power module to provide power to the motor 106 and wheels 108 of the electric vehicle 100, but the embodiment is not limited thereto. For example, the power module may be bidirectional and may convert DC power to AC power, or convert AC power to DC power, such as during regenerative braking. The traction inverter 102 may be a three-phase inverter, a single-phase inverter, or a multi-phase inverter.

[0038] Figure 2A and Figure 2B A side view of a system 200 is depicted, which may include a power module 202, a first heat sink 204, a second heat sink 206, a protruding interlocking feature 208, recessed interlocking features 210 and 212, and thermal interface materials 222 and 224. The system 200 may include a power module 202, wherein the first heat sink 204 may be located above a first surface 218 (e.g., a top surface 218) of the power module 202, and the second heat sink 206 may be located below a second surface 220 (e.g., a bottom surface 220) of the power module 202. The power module 202 may include a plurality of protruding interlocking features 208. The protruding interlocking features 208 may include any suitable shape, geometry, and configuration. For example, in some embodiments, the protruding interlocking features 208 may actually be replaced with recessed portions configured to receive corresponding mating protrusions on the heat sinks 204, 206. However, as Figure 2A As shown, in one embodiment, the protruding interlocking features 208 include a plurality of protrusions on the top surface 218, wherein the protruding interlocking features 208 include extensions of the top surface 218. The power module 202 may also include a plurality of protruding interlocking features 208 on the bottom surface 220 of the power module 202, wherein the protruding interlocking features 208 include extensions of the bottom surface 220.

[0039] The protruding interlocking features 208 may include any suitable size, shape, or configuration. Figure 2A Only two protruding interlocking features 208 are depicted on each of the top surface 218 and the bottom surface 220, but one of ordinary skill in the art will appreciate that any suitable number of protruding interlocking features 208 is within the scope of the embodiments described herein. Figure 3AAs shown, alternative embodiments may include, for example, four protruding interlocking features, as described in detail below. Further, the number, size, or configuration of the protruding interlocking features 208 on the top surface 218 may be the same as or different in one or more aspects from the protruding interlocking features 208 on the bottom surface 220. In addition, one or more of the protruding interlocking features 208 may include any suitable material known in the art, including but not limited to copper, aluminum, or alloys of copper and aluminum. Each of the protruding interlocking features 208 may be made of the same material composition, or one or more interlocking features 208 may include a material composition that is different from the material composition of the other protruding interlocking features 208.

[0040] In another implementation, only one side of the power module 202 may include a plurality of protruding interlocking features 208. For example, the top surface 218 of the power module may include a plurality of protruding interlocking features 208, but the bottom surface 220 of the power module 202 may include a flat surface.

[0041] The plurality of protruding interlocking features 208 may all be located at an equal distance from the edge of the power module 202. For example, one of the plurality of protruding interlocking features 208 may be located, for example, at about 2 mm from the first edge 226 of the power module, and one of the other plurality of protruding interlocking features 208 may be located, for example, at about 2 mm from the second edge 228 of the power module 202. In another specific implementation, the positions of the protruding interlocking features 208 from the first edge 226 and the second edge 228 of the power module 202 may be different compared to each other. For example, one of the plurality of protruding interlocking features 208 may be located, for example, at about 3 mm from the first edge 226 of the power module 202, and one of the other protruding interlocking features 208 may be located, for example, at about 5 mm from the second edge 228 of the power module 202.

[0042] The power module 202 may include, for example, an approximately 800 volt silicon carbide inverter (e.g., for electric vehicles), although other suitable structures and uses may also be envisioned. The power module 202 may include one or more silicon carbide (SiC)-based power modules that provide relatively high power density and efficiency required to extend battery range and performance. The power module 202 may contain circuits and components configured to convert direct current (DC) from an electric vehicle battery into alternating current (AC) current, which may be utilized in an electric motor that drives a propulsion system. The power module 202 may be mounted on one or more power board assemblies. The power module 202 may include a combination of transistors, diodes, metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), and silicon controlled rectifiers (SCRs). The power module 202 may include a combination of transistors configured to both half-bridge and H-bridge configurations, which may allow the ability to switch the direction of current through the motor from a single voltage power supply. In addition, the power module 202 may also include up to six transistors for inverter applications (such as switching direct current to alternating current).

[0043] First heat sink 204 may include a plurality of recessed interlocking features 210 on surface 216, wherein recessed interlocking features 210 include blind cavities in surface 216. Second heat sink 206 may also include a plurality of recessed interlocking features 212 on surface 214, wherein recessed interlocking features include blind cavities in surface 214.

[0044] The recessed interlocking features 210 and 212 may include any suitable size, shape, or configuration. Figure 2A Only two recessed interlocking features 210 and 212 are depicted on each of the surface 216 of the first heat sink 204 and the surface 214 of the second heat sink 206, but one of ordinary skill in the art will appreciate that any suitable number of recessed interlocking features 210 and 212 is within the scope of the embodiments described herein. Figure 3A As shown, an alternative embodiment may include, for example, four recessed interlocking features, as described in detail below. Further, the number, size, or configuration of the recessed interlocking features 210 on the surface 216 may be the same as the recessed interlocking features 212 on the surface 214 or may differ in one or more aspects.

[0045] The plurality of recessed interlocking features 210 and 212 may all be located at an equal distance from the edge of the first heat sink 204 or the second heat sink 206. For example, one of the plurality of recessed interlocking features 210 may be located, for example, approximately 2 mm from the first edge 230 of the first heat sink 204, and one of the other plurality of recessed interlocking features 210 may be located, for example, approximately 2 mm from the second edge 232 of the first heat sink 204. In another specific implementation, the positions of the recessed interlocking features 210 and 212 from the edges of the first heat sink 204 and the second heat sink 206 may be different from each other. For example, one of the plurality of recessed interlocking features 210 may be located, for example, approximately 3 mm from the first edge 230 of the first heat sink 204, and one or more of the other plurality of recessed interlocking features 210 may be located, for example, approximately 5 mm from the second edge 232 of the heat sink 204.

[0046] The recessed interlocking features 210 and 212 and the protruding interlocking feature 208, when engaged, can generate a force that causes the TIM layer (discussed in more detail below) to be more evenly spread over the first heat sink 204 and the second heat sink 206, which in turn can reduce the bond wire thickness. In some examples, the entire applied TIM layer can be within 15%, 10%, 5%, 3%, 2%, 1% or less of the median thickness. In addition, the entire outer surface of all power modules (except for exposed electrical connections) can be covered by the TIM. The reduction in bond wire thickness can relieve stress on the power module 202, which can reduce the risk of cracking and failure of the power module structure.

[0047] The surface 216 of the first heat sink 204 and the surface 216 of the second heat sink 206 may include thermal interface material (TIM) layers 222 and 224, respectively, to further facilitate thermal conduction between the first heat sink 204 and the power module 202, and between the second heat sink 206 and the power module 202. The TIM layers 222 and 224 may include any suitable thermally conductive tape, gel, thermally conductive epoxy, solder, grease, gap-filling pads, phase change materials, or combinations thereof.

[0048] The TIM layers 222 and 224 on the surface 214 or 216 may include a TIM extending across substantially the entire surface 214 and 216 or across only a portion of the surface. In addition, the TIM layers 222 and 224 may include a TIM across a portion of the surfaces 214 and 216 between the recessed interlocking features 210 and 212. The amount of TIM extending across the surface 214 may be the same as the amount of TIM extending across the surface 216 or may be different in one or more aspects. In addition, the TIM layers 222 and 224 may include any suitable material known in the art, including but not limited to silicone elastomers, fiberglass, or combinations thereof. The surface 214 may include a TIM layer 222 made of the same material composition as the TIM layer 224 included on the surface 216, or the TIM layer 222 may include a material composition different from the material composition of the TIM layer 224.

[0049] The TIM layers 222 and 224 may be uniformly composed of the same material. In another implementation, the TIM layers 222 and 224 are a composite of different materials. For example, the TIM layers 222 and 224 may include a combination of gel and grease. For example, in another implementation, the TIM layers 222 and 224 disposed in the blind cavities of the recessed interlocking features 210 and 212 may be composed of a different material than the TIM layers 222 and 224 included on the surfaces 214 and 216.

[0050] The first heat sink 204 and the second heat sink 206 can provide heat dissipation for the power module 202. The heat sinks 204 and 206 can include multiple components. The material of the heat sinks 204 and 206 can be selected based on the required thermal performance required to draw heat away from the power module 202. For example, the heat sinks 204 and 206 can include an aluminum alloy that has high thermal conductivity while being mechanically soft. In another embodiment, the heat sinks 204 and 206 can include copper. In some embodiments, the heat sinks 204 and 206 can be similar to radiators used in internal combustion engines and can include a circulating fluid or gas therein. The heat sinks 204 and 206 can be in an extruded, folded fin, bonded fin, active fan, stamped, or cross-cut configuration.

[0051] like Figure 2BAs shown, the plurality of protruding interlocking features 208 on the top surface 218 of the power module 202 may mate with the plurality of recessed interlocking features 210 of the first heat sink 204. Additionally, the plurality of protruding interlocking features 208 on the bottom surface 220 of the power module 202 may mate with the plurality of recessed interlocking features 212 of the second heat sink 206. The plurality of recessed interlocking features 210 and 212 may be wider than the plurality of protruding interlocking features 208 of the power module 202 such that substantially the entire protruding interlocking features 208 are received therein. Lubricating material may be included on top of the TIM layers 222 and 224 to facilitate the mating of the protruding interlocking features 208 with the recessed interlocking features 210 and 212. The top surface 218 and the bottom surface 220 of the power module 202 may include an adhesive material (not shown) to keep the heat sinks 204 and 206 mated with the power module 202 when the power module 202 generates a large amount of heat.

[0052] Figure 3A and Figure 3B Another embodiment system 300 is depicted. In an embodiment of the system 300, the protruding interlocking features 314 on the power module 304 may be located within the epoxy molding compound 308 (eg, Figure 3A as shown) or copper layer 324 (as shown Figure 3B The protruding interlocking features 314 may be located on any area of ​​the epoxy molding compound 308 or the copper layer 324 as long as the protruding interlocking features 314 are aligned with the corresponding recessed interlocking features 312 located on the heat sinks 302 and 316. Figure 3A and Figure 3B In both, the TIM layer 322 on both heat sinks 302 and 316 may include a TIM that extends across substantially the entire surface of the heat sinks 302 and 316 or across only a portion of the surface of the heat sinks. In another embodiment, the TIM may be included only in the area where the power module 304 will mate with the heat sinks 302 and 316.

[0053] Heat sinks 302 and 316 may include integral fluid-conducting microchannels for liquid cooling. In particular, heat sinks 302 and 316 may include one or more inlet ports 306 for supplying liquid coolant within the respective heat sinks and one or more outlet ports 326 for exhausting the coolant that has passed through the fluid-conducting microchannels. Heat sinks 302 and 316 may also include fluid seals 310 for fluidically sealing inlet ports 306 and outlet ports 326. The fluid-conducting microchannels coupled with the TIM layer may allow for more efficient cooling of the power module.

[0054] Figure 4A and Figure 4B Depicted is an example system 200 (eg Figure 2A and Figure 2B200). However, system 400 differs from system 200 in that surface 216 of first heat sink 204 and surface 214 of second heat sink 206 do not include a plurality of recessed interlocking features (such as Figure 4A Surface 216 of first heat sink 204 and surface 214 of second heat sink 206 may be substantially flat or otherwise continuous surfaces.

[0055] The plurality of protruding interlocking features 208 on the top surface 218 of the power module 202 may contact the surface 216 of the first heat sink 204, wherein a gap is formed between the surface 216 and the top surface 218. Additionally, the plurality of protruding interlocking features 208 on the bottom surface 220 of the power module 202 may contact the surface 214 of the second heat sink 206, wherein a gap is formed between the surface 214 and the bottom surface 220. The gap formed between the heat sinks 204 and 206 and the power module 202 may be uniform. In another specific implementation, the height of the plurality of protruding interlocking features 208 on the top surface 218 may be different from the height of the plurality of protruding interlocking features on the bottom surface 220. Thus, the height of the gap formed when the protruding interlocking features 208 on the top surface 218 contact the surface 216 of the first heat sink 204 may be different from the height of the gap formed when the protruding interlocking features 208 on the bottom surface 220 contact the surface 214 of the second heat sink 206.

[0056] The TIM layers 222 and 224 on the surface 214 or 216 may include a TIM that extends across substantially the entire area where the power module is not mated with the heat sink 204 and 206 or across a portion of the area. In addition, the thickness of the TIM layers 222 and 224 may fill the entire gap formed between the heat sink and the surface of the power module. In another specific implementation, the amount of TIM that fills the gap between the top surface 218 and the surface 216 of the first heat sink 204 may be the same as the amount of TIM that fills the gap between the bottom surface 220 and the surface 214 of the second heat sink 206 or may be different in one or more aspects.

[0057] In another embodiment, Figure 4BAs shown, the system 400 may include a power module 202 and a single heat sink 204 (or 206). The plurality of protruding interlocking features 208 may be included only on a single surface (top surface 218 or bottom surface 220) of the power module 202, while the other surface (top surface 218 or bottom surface 220) may be a flat or otherwise free surface. The single heat sink 204 (or 206) may not include a plurality of recessed interlocking features 210 (or 212). The surface 218 (or 220) includes the plurality of protruding interlocking features 208 on the power module 202, and the plurality of protruding interlocking features may be close to or contact the surface 216 (or 214) of the single heat sink 204 or 206, so that a gap is formed between the surface 216 (or 214) of the heat sink 204 or 206 and the surface 218 (or 220) of the power module 202. The TIM layer 222 (or 224) may uniformly fill the gap between the surface 216 (or 214) of the heat sink 204 (or 206) and the surface 218 (or 220) of the power module 202. In addition, the TIM layer 222 (or 224) on the surface 216 (or 214) of a single heat sink 204 (or 206) may include a TIM that extends across substantially the entire area or across a portion of the area where the power module may not be in contact with the single heat sink 204 (or 206).

[0058] Figure 5A and Figure 5B Depicted is an example system 200 (eg Figure 2A and Figure 2B Another embodiment system 500 is similar to that shown in FIG. However, system 500 is different from system 200 in that Figure 5A As shown, the height of the plurality of protruding interlocking features 208 on the top surface 218 may be greater than the depth of the plurality of recessed interlocking features 210 on the surface 216 of the first heat sink 204. In addition, the height of the plurality of protruding interlocking features 208 on the bottom surface 220 of the power module 202 may be greater than the depth of the plurality of recessed interlocking features 212 on the surface 214 of the second heat sink 206.

[0059] The plurality of protruding interlocking features 208 on the top surface 218 of the power module 202 may cooperate with the plurality of recessed interlocking features 210 of the first heat sink 204 such that a gap is formed between the surface 216 and the top surface 218. Additionally, the plurality of protruding interlocking features 208 on the bottom surface 220 of the power module 202 may cooperate with the plurality of recessed interlocking features 212 of the second heat sink 206 such that a gap is formed between the surface 214 and the bottom surface 220. The gap formed between the heat sinks 204 and 206 and the power module 202 may be uniform. In another specific implementation, the height of the plurality of protruding interlocking features 208 on the top surface 218 may be different from the height of the plurality of protruding interlocking features 212 on the bottom surface 220. Therefore, the height of the gap formed when the protruding interlocking feature 208 on the top surface 218 cooperates with the multiple recessed interlocking features 210 of the first heat sink 204 may be different from the height of the gap formed when the protruding interlocking feature 208 on the bottom surface 220 cooperates with the multiple recessed interlocking features 212 of the second heat sink 206.

[0060] The TIM layers 222 and 224 on the surface 214 or 216 may include a TIM extending across substantially the entire area where the power module 202 is not in contact with the heat sinks 204 and 206, or across a portion of the area. In addition, the thickness of the TIM layers 222 and 224 may fill the entire gap formed between the heat sink and the surface of the power module. In another specific implementation, the amount of TIM that fills the gap between the top surface 218 and the surface 216 of the first heat sink 204 may be the same as the amount of TIM that fills the gap between the bottom surface 220 and the surface 214 of the second heat sink 206, or may be different in one or more aspects.

[0061] In another embodiment, Figure 5BAs shown, the system 500 may include a power module 202 and a single heat sink 204 (or 206). The plurality of protruding interlocking features 208 may be included only on a single surface (top surface 218 or bottom surface 220) of the power module 202, while the other surface (top surface 218 or bottom surface 220) may be a flat, free surface. The single heat sink 204 (or 206) may include a plurality of recessed interlocking features 210 (or 212), which may have a depth less than the height of the plurality of protruding interlocking features 208. The plurality of protruding interlocking features 208 on the power module 202 may be received within the plurality of recessed interlocking features of the heat sink 204 (or 206), so that a gap is formed between the surface 216 (or 214) of the heat sink 204 (or 206) and the surface 218 (or 220) of the power module 202. The TIM layer 222 (or 224) may uniformly fill the gap between the surface 216 (or 214) of the heat sink 204 (or 206) and the surface 218 (or 220) of the power module 202. In addition, the TIM layer 222 (or 224) on the surface 216 (or 214) of the heat sink 204 (or 206) may include a TIM that extends across substantially the entire area where the power module is not mated to a single heat sink 204 (or 206) or across a portion of that area.

[0062] Figure 6 An exemplary method 600 for aligning a heat sink with a power module is depicted. Figure 6 As shown, the method 600 may include, at step 610, forming one or more interlocking features on the heat sink 204, 206 and the power module 202. For example, a copper plate may be welded to the outer surface of the power module 202 to form the protruding interlocking features 208. Correspondingly, the recessed interlocking features 210, 212 may be machined or laser drilled into the surfaces 214, 216 of the heat sink 204, 206. In addition, any suitable analysis (e.g., finite element analysis) may be performed to determine the ideal positions for both the protruding interlocking features 208 and the recessed interlocking features 210, 212.

[0063] Once the protruding interlocking features 208 and the recessed interlocking features 210 and 212 have been formed on the power module 202 and the heat sinks 204, 206, respectively, the thermal interface material 222, 224 may be applied to the surfaces of the heat sinks 204, 206 or the surfaces 218, 220 of the power module 202 at step 620. For example, solder paste, silver sintering paste, or a pump may be used to dispense the TIM material onto at least one of the heat sinks 204, 206 or the power module 202. In one example, the pump may be a piston pump that may create little or no friction during the dispensing of the TIM. In other examples, the pump may be a screw pump for dispensing the TIM. The TIM may be dispensed or otherwise deposited onto the heat sink 204, 206 or the power module 202 in any suitable pattern, including but not limited to, such as dots, serpentines, or spirals.

[0064] Once the TIM has been dispensed on the heat sinks 204, 206, the protruding interlocking features 208 may be aligned with the recessed interlocking features 210 and 212. Subsequently, at step 630, the protruding interlocking features 208 may be mated with (e.g., inserted into) the recessed interlocking features 210 and 212 to align the one or more heat sinks 204, 206 with the power module 202. A deformable washer or a spring-acting clamp may be used to align the heat sinks 204, 206 and the power module 202 with each other. At step 640, the heat sinks 204, 206 and the power module 202 may be interlocked with each other.

[0065] Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein.It is intended that the specification and examples be considered exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

Claims

1. A system comprising: a power module, wherein the power module includes a first interlocking feature on a first surface of the power module; as well as at least one heat sink, wherein the at least one heat sink comprises a second interlocking feature on a surface of the at least one heat sink, Wherein the surface of the at least one heat sink comprises a layer of thermal interface material. 2 . The system of claim 1 , wherein the power module includes the first interlocking feature on a second surface of the power module, wherein the second surface is separated from the first surface by a width of the power module.

3. The system of claim 1, wherein the first interlocking feature is a protruding interlocking feature.

4. The system of claim 1, wherein the second interlocking feature is a recessed interlocking feature.

5. The system of claim 4, wherein the recessed interlocking feature is a blind cavity.

6. The system of claim 1, wherein the thermal interface material layer comprises thermally conductive tape, gel, thermally conductive epoxy, solder, grease, gap filler pads, and phase change material.

7. The system of claim 2, wherein the first surface and the second surface comprise epoxy molding compound or a copper layer.

8. The system of claim 7, wherein the first interlocking feature is located on the epoxy molding compound or the copper layer.

9. The system of claim 1, wherein the at least one heat sink comprises an inlet port or an outlet port.

10. The system of claim 4, wherein the thermal interface material layer extends uniformly across the surface between the recessed interlocking features of the at least one heat spreader.

11. A method for aligning a power module and a heat sink, the method comprising: forming a first interlocking feature on a surface of the power module; forming a second interlocking feature on a surface of the heat sink; applying a layer of thermal interface material on the surface of the heat sink or the power module; as well as The first interlocking feature is mated with the second interlocking feature. 12 . The method of claim 11 , wherein forming the second interlocking feature comprises machining or laser drilling into the surface of the heat sink.

13. The method of claim 11, wherein the first interlocking feature is a protruding interlocking feature.

14. The method of claim 11, wherein the second interlocking feature is a recessed interlocking feature.

15. The method of claim 14, wherein the thermal interface material layer is uniformly applied to the surface of the heat sink between the recessed interlocking features.

16. The method according to claim 11, further comprising: Finite element analysis is performed to determine ideal locations for both the first interlocking feature and the second interlocking feature. 17 . The method of claim 11 , wherein applying the thermal interface material layer comprises dispensing the thermal interface material layer onto the surface of the heat sink or the power module using a solder paste, a silver sintering paste, or a pump.

18. The method of claim 16, wherein applying the layer of thermal interface material comprises any suitable pattern, such as dots, serpentines, or spirals.

19. The method of claim 11, further comprising: Align the heat sink with the power module.

20. The method of claim 19, wherein the heat sink and the power module are aligned by a deformable washer or a spring clamp.

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