Package for semiconductor device with double-sided cooling

Abstract

The device may include a semiconductor die. The device may include a bottom heat spreader and a top heat spreader, the bottom heat spreader and the top heat spreader are disposed on both sides of the semiconductor die, the area of the top heat spreader is larger than the area of the semiconductor die, the top heat spreader extends beyond the semiconductor die, the area of the bottom heat spreader is larger than the area of the semiconductor die, the bottom heat spreader extends beyond the semiconductor die, and the sum of the thicknesses of the top heat spreader and the bottom heat spreader is at least four times the thickness of the semiconductor die.

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 366,451, filed on June 15, 2022, entitled "SEMICONDUCTOR DEVICE PACKAGE WITH DUAL - SIDED COOLING", the contents of which are hereby incorporated by reference in their entirety and form a part of this specification for all purposes as if fully set forth herein.

[0002] This application relates to semiconductor device packages. In particular, some embodiments relate to cooling integrated circuits and methods of manufacturing integrated circuit assemblies.

Background Art

[0003] Semiconductor devices are used in a wide variety of applications. In some applications, high electrical loads can occur that can cause significant heating of the semiconductor device. There are many problems associated with high electrical loads, such as harmful heating of semiconductor devices. Current cooling solutions may be insufficient for certain applications. Therefore, there is a need to improve the cooling of semiconductor devices.

Summary of the Invention

[0004] Each of the technological innovations described in the claims has multiple aspects, and none of them alone is responsible for any desirable attribute without limiting the claims. Some of the prominent features of this disclosure are briefly described here without limiting the claims.

[0005] In some embodiments, the technology described herein includes a semiconductor die, a bottom heat spreader, and a top heat spreader. The bottom heat spreader and the top heat spreader are disposed on both sides of the semiconductor die. The area of the top heat spreader is larger than the area of the semiconductor die, and the top heat spreader extends beyond the semiconductor die. The area of the bottom heat spreader is larger than the area of the semiconductor die, and the bottom heat spreader extends beyond the semiconductor die. The total thickness of the top heat spreader and the bottom heat spreader is at least four times the thickness of the semiconductor die. The present invention relates to an apparatus with two-sided surge power heat dissipation.

[0006] In some embodiments, the technology described herein relates to an apparatus in which the bottom heat spreader has at least one electrical contact and the top heat spreader has at least one electrical contact.

[0007] In some embodiments, the technology described herein further includes a clip. The clip is disposed on the same side of the semiconductor die as the top heat spreader and is configured to be in electrical and thermal contact with the semiconductor die. The clip is positioned between the semiconductor die and the top heat spreader.

[0008] In some embodiments, the technology described herein relates to an apparatus in which the clip includes folded or formed sheet metal.

[0009] In some embodiments, the technology described herein further includes a thermistor or other passive die disposed on the clip.

[0010] In some embodiments, the technology described herein relates to an apparatus in which both the bottom heat spreader and the top heat spreader are soldered to the semiconductor die.

[0011] In some embodiments, the technology described herein relates to an apparatus in which the top heat spreader includes a lead frame.

[0012] In some embodiments, the technology described herein relates to an apparatus in which at least one of the top and bottom heat spreaders includes copper.

[0013] In some embodiments, the technology described herein relates to an apparatus in which at least one of the top and bottom heat spreaders includes metal.

[0014] In some embodiments, the technology described herein relates to an apparatus in which both the top and bottom heat spreaders include copper or other metal.

[0015] In some embodiments, the technology described herein relates to an apparatus in which a semiconductor die is positioned between a top heat spreader and a bottom heat spreader such that the semiconductor die has a position that is substantially neutral with respect to symmetric thermal expansion.

[0016] In some embodiments, the technology described herein relates to an apparatus in which the thickness of the top heat spreader is greater than 1 mm and the thickness of the bottom heat spreader is greater than 1 mm.

[0017] In some embodiments, the technology described herein relates to an apparatus in which the thickness of the top heat spreader is greater than 2 mm and the thickness of the bottom heat spreader is greater than 2 mm.

[0018] In some embodiments, the technology described herein relates to an apparatus in which the thickness of the top heat spreader is greater than 3 mm and the thickness of the bottom heat spreader is greater than 3 mm.

[0019] In some embodiments, the technology described herein relates to an apparatus with double-sided surge power heat dissipation that includes a semiconductor die, a bottom heat spreader, and a top heat spreader, where the bottom heat spreader and the top heat spreader are disposed on both sides of the semiconductor die, and where both the bottom heat spreader and the top heat spreader together have sufficient heat to maintain the semiconductor die at a temperature of less than 180 degrees when receiving a surge load of up to 100 W for up to 0.5 seconds.

[0020] In some embodiments, the techniques described herein relate to an apparatus in which a bottom heat spreader has at least one electrical contact and a top heat spreader has at least one electrical contact.

[0021] In some embodiments, the techniques described herein further include a clip that is disposed on the same side of the semiconductor die as the top heat spreader and is configured to make electrical and thermal contact with the semiconductor die, and the clip is positioned between the semiconductor die and the top heat spreader.

[0022] In some embodiments, the techniques described herein relate to an apparatus that includes a folded or formed sheet metal clip.

[0023] In some embodiments, the techniques described herein further include a thermistor or other passive die disposed on the clip.

[0024] In some embodiments, the techniques described herein relate to an apparatus in which both the bottom heat spreader and the top heat spreader are soldered to the semiconductor die.

[0025] In some embodiments, the techniques described herein relate to an apparatus in which the top heat spreader includes a lead frame.

[0026] In some embodiments, the techniques described herein relate to an apparatus in which at least one of the top and bottom heat spreaders includes copper.

[0027] In some embodiments, the techniques described herein relate to an apparatus in which at least one of the top and bottom heat spreaders includes a metal.

[0028] In some embodiments, the techniques described herein relate to an apparatus in which both the top and bottom heat spreaders include copper or another metal.

[0029] In some aspects, the technology described herein relates to an apparatus in which a semiconductor die is positioned between an upper and a bottom heat spreader such that the semiconductor die has a position that is substantially neutral with respect to symmetric thermal expansion.

[0030] In some aspects, the technology described herein relates to an apparatus in which the thickness of the upper heat spreader is greater than 1 mm and the thickness of the bottom heat spreader is greater than 1 mm.

[0031] In some aspects, the technology described herein relates to an apparatus in which the thickness of the upper heat spreader is greater than 2 mm and the thickness of the bottom heat spreader is greater than 2 mm.

[0032] In some aspects, the technology described herein relates to an apparatus in which the thickness of the upper heat spreader is greater than 3 mm and the thickness of the bottom heat spreader is greater than 3 mm.

[0033] In some aspects, the technology described herein relates to a packaged semiconductor device including a semiconductor die, a bottom heat spreader, and an upper heat spreader, wherein the bottom heat spreader and the upper heat spreader are disposed on opposite sides of the integrated semiconductor die, the area of the upper heat spreader is larger than the area of the semiconductor die, the upper heat spreader extends beyond the semiconductor die, the area of the bottom heat spreader is larger than the area of the semiconductor die, the bottom heat spreader extends beyond the semiconductor die, and the sum of the thicknesses of the upper heat spreader and the bottom heat spreader is at least four times greater than the thickness of the semiconductor die; a printed circuit board having the upper heat spreader positioned therebetween the printed circuit board and the packaged semiconductor die; and a cooling solution in thermal contact with the bottom heat spreader.

[0034] In some embodiments, the techniques described herein relate to a semiconductor device assembly in which a bottom heat spreader is configured to be electrically and thermally connected to at least one contact pad of a printed circuit board, and a top heat spreader is configured to be in thermal communication with a heat sink.

[0035] In some embodiments, the techniques described herein relate to an apparatus in which a top heat spreader is electrically and thermally connected to a contact pad of a printed circuit board that is different from at least one contact pad.

[0036] In some embodiments, the techniques described herein relate to a semiconductor device assembly in which a semiconductor die is a power switching die.

[0037] In some embodiments, the techniques described herein relate to a semiconductor device assembly in which a cooling solution includes a heat sink.

[0038] In some embodiments, the techniques described herein relate to a semiconductor device assembly in which the thickness of the top heat spreader is greater than 1 mm and the thickness of the bottom heat spreader is greater than 1 mm.

[0039] In some embodiments, the techniques described herein relate to a method of manufacturing any of the embodiments described herein.

[0040] For purposes of summarizing the disclosure, certain aspects, advantages, and novel features of the innovations are described herein. It is to be understood that not necessarily all such advantages can be achieved in accordance with any particular embodiment. Thus, the innovations may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages taught herein without necessarily achieving other advantages that may be taught or suggested herein.

Brief Description of the Drawings

[0041] These and other features, aspects, and advantages of the present disclosure are not limiting, but are illustrated with reference to the drawings of specific embodiments intended to be exemplary. It should be understood that the accompanying drawings, which are incorporated herein and constitute a part of this specification, are for the purpose of illustrating the concepts disclosed herein and may not be to scale.

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DETAILED DESCRIPTION OF THE INVENTION

[0053] The following detailed description of specific embodiments presents various descriptions of specific embodiments. However, the technological innovations described in this specification can be implemented in many different ways, for example, as defined and encompassed by the claims. In this specification, reference is made to the drawings in which similar reference numerals and / or terms may indicate elements that are identical or functionally similar. It should be understood that the elements shown in the figures are not necessarily illustrated in exact proportions. Furthermore, it should be understood that specific embodiments may include more elements than those illustrated in the drawings and / or a portion of the elements illustrated in the drawings. Additionally, some embodiments may incorporate any suitable combination of features from two or more drawings. The headings provided in this specification are for convenience only and do not necessarily affect the scope or meaning of the claims. Introduction

[0054] An electronic component including one or more integrated circuit (IC) dies may be deployed in a variety of applications. For example, such a component may form part of a power electronics system. In some cases, such a power electronics system may be used to supply power to an electric vehicle or may be used as part of a stationary energy storage system, such as a system for storing solar energy. There are many other applications for such systems. In some cases, the component may comprise a diode switch, a field effect transistor (FET) such as a metal oxide semiconductor field effect transistor (MOSFET) (e.g., a GaN MOSFET), an insulated gate bipolar transistor (IGBT), other bipolar transistors, or any suitable combination thereof. Any of these components may be implemented in any of the dies of the semiconductor device package disclosed herein. In certain applications, such switches may be included in an inverter that converts a direct current (DC) voltage to an alternating current (AC) voltage or a rectifier that converts AC to DC. In these components, the thermal output during operation can be significant. In certain embodiments, the electronic component may be provided in the form of a packaged semiconductor device.

[0055] A power electronics system may generate a significant amount of heat both under steady-state load conditions and under surge conditions. Such heat can cause serious problems. For example, excessive heat can lead to one or more of component damage, shortened lifespan, reduced reliability, and reduced performance. For example, excessive thermal stress can embrittle solder joints and / or damage semiconductor components. In some applications, a surge load can cause a rapid temperature rise. For example, high surge loads can occur in various applications when starting a portable compressor, an HVAC (heating, ventilation, and air conditioning) system, a refrigeration system, an electric motor, a power converter, etc.

[0056] Even a short surge load of about 1 / 2 second to 1 second can cause a significant change in temperature. With conventional cooling solutions, it may be difficult to cope with the rapid rise in heat generation. For example, as shown in Figure 1A, a die operating in a steady state and consuming 18 W of power can operate at a temperature of about 100 °C when using conventional cooling through a printed circuit board (PCB). When a 100 W surge load is applied for 1 / 2 second, the die temperature can rise by about 50 °C or more. Depending on the specific cooling solution, after 1 second, the die temperature can rise to about 220 °C or more. Figure 1A includes curves of die temperature over time for two dies with different surface areas, and Example Die B has a larger surface area than Example Die A. In some cases, the die can be directly attached to a lead frame or a die paddle (which can operate as a heat spreader within a package for a molded semiconductor device). The semiconductor device package may be fixed to a heat sink, a cold plate, etc. to assist in heat dissipation. However, adding mass to the heat sink, and / or adding an external heat spreader (for example, by adding a pedestal on top of the heat sink or by increasing the mass of the heat sink) may not be very helpful in managing the die temperature during surge conditions. The semiconductor device package may lack good thermal contact with the added mass, and thus may not be able to take advantage of the added heat capacity in a short time. For example, heat may move through a thermal interface material (such as thermal paste, thermal pad, solder, etc.) before reaching the heat sink, which may limit the heat transfer rate, and this can play an important role in managing the die temperature during a surge load. Figure 1B shows an exemplary simulation of the temperature gradient of the die package after different times have elapsed under a transient load.

[0057] Often, electronic components may be designed to operate under steady-state conditions. For example, the heat transfer material within a component may be sized to handle heat from typical load conditions. Such an approach can offer many advantages, such as size minimization and cost reduction, since the materials used can be reduced. However, such an approach may not be suitable for certain types of use cases, such as handling large-scale loads and / or surge loads.

[0058] Packages for semiconductor devices may be cooled from one side, such as bottom cooling through a PCB. However, heat conduction through a PCB may be insufficient for certain applications. In some cases, a "coin" comprising copper or another thermally conductive material may be embedded within the PCB under the electronic component to facilitate cooling. However, such an approach can add additional cost and complexity to the PCB and may reduce the density of components on the PCB. Further, a power electronics system can raise the temperature of a PCB assembly to temperatures exceeding 100°C, which can limit the flow of heat away from the semiconductor device package through the PCB. Alternatively, in some cases, the PCB may be configured with holes that expose the bottom surface of the semiconductor device package, and a heat sink or other heat transfer device may make thermal contact with the bottom surface of the semiconductor device package through the holes. In some cases, top-side cooling may be used to cool the semiconductor device package, as described, for example, in U.S. Patent No. 10,658,276 entitled "Device with Top-Side Substrate," the contents of which are incorporated by reference herein in their entirety for all purposes as if fully set forth herein.

[0059] In some cases, the cooling solution may be designed to handle both large-scale and sustained loads and short-term surge loads. Thus, the cooling solution may be designed to have not only a large heat capacity but also a rapid heat transport capacity. The present disclosure describes examples of systems and techniques for providing an efficient cooling solution that does not cause further complication of the PCB design or component installation process. Preferably, such a cooling solution may be manufactured using established and efficient manufacturing methods. Double-sided cooling package

[0060] In some embodiments, the heat spreader may be in thermal contact with both sides of the die and may function as a thermal reservoir for directly and simultaneously dissipating heat above and below the die. In some embodiments, the top heat spreader and the bottom heat spreader may be in contact with and / or in thermal communication with the semiconductor die. To facilitate heat dissipation, the top heat spreader and the bottom heat spreader may each be thicker than the semiconductor die. The total thickness of the top heat spreader and the bottom heat spreader may be at least four times the thickness of the semiconductor die. Thereby, the dissipation of power surges from the steady state can be promoted. The total thickness of the top heat spreader and the bottom heat spreader may be in the range from four times the thickness of the semiconductor die to ten times the thickness of the semiconductor die. In some embodiments, the top heat spreader and the bottom heat spreader together may have sufficient thermal mass to maintain the die at a temperature below 170 °C, below 160 °C, or below 150 °C when the die is subjected to a surge load of up to 100 W or up to 160 W from the steady state for 0.5 seconds. In some embodiments, the top heat spreader and the bottom heat spreader together may have sufficient thermal mass to maintain the die at a temperature below 200 °C, below 190 °C, or below 180 °C when the die is subjected to a surge load of up to 100 W or up to 160 W from the steady state for 1 second. The top heat spreader and the bottom heat spreader may each have an area larger than the area of the die. The top heat spreader and the bottom heat spreader may each extend beyond the die.

[0061] Figures 2A and 2B illustrate an exemplary embodiment of a dual heat spreader system. As shown in FIGS. 2A and 2B, the top heat spreader 201 and the bottom heat spreader 202 may be in thermal contact with the die 203 via solders 204 and 205. The die 203 may be an IC die. The die 203 may be a semiconductor switching die. In some embodiments, sintering or epoxy bonding may be used instead of solders 204 and 205. In some embodiments, the dual heat spreader (e.g., plate) may be nested, as shown, for example, in FIG. 2A. In some other embodiments, the dual heat spreaders may be stacked on top of each other, as depicted, for example, in FIG. 2B.

[0062] The top heat spreader 201 may comprise copper. For example, the top heat spreader 201 may be mostly or entirely copper. The bottom heat spreader 202 may comprise copper. For example, the bottom heat spreader 202 may be mostly or entirely copper. The top heat spreader 201 and the bottom heat spreader 202 may be thick enough to simultaneously dissipate heat associated with power surges. Such thickness may be significantly greater than a conventional thickness sufficient to achieve steady state heat dissipation to stabilize the maximum die temperature. The top heat spreader 201 and the bottom heat spreader 202 may suppress the temperature rise of the die 203 in the presence of an instantaneous power surge. Thus, the dual heat spreader system may maintain the die and the package within the power surge specifications.

[0063] The die 203 may be positioned between the top heat spreader 201 and the bottom heat spreader 202 so as to have a position substantially neutral to symmetric thermal expansion. Thereby, the coefficient of thermal expansion (CTE) mismatch stress may be reduced or eliminated.

[0064] Figure 2C illustrates numerous exemplary embodiments of a dual heat spreader. In some embodiments, only two components (e.g., top heat spreader 201 and bottom heat spreader 202) may be present, while in other embodiments, more than two components may be present, and some components may be joined using a conductive bonding material 210 such as solder, sintered paste, or epoxy. For example, the exemplary embodiments "LI" and "LII" shown in Figure 2C may have one or more components 202' attached to the bottom heat spreader portion and in electrical communication. In some embodiments, the heat spreader components may be joined by other methods such as ultrasonic welding, laser welding, diffusion bonding, impact welding, friction welding, or rivet bonding.

[0065] Figure 3 is an exemplary diagram of heat flow from a die to a dual heat spreader according to some embodiments. As shown in Figure 3, die 203 may be disposed between top heat spreader 201 and bottom heat spreader 202. Top heat spreader 201 may be in thermal and / or electrical contact with PCB 206 via interface material 207. The interface material may be a metal such as a copper contact pad, for example. In some embodiments, interface material 207 may not be present. In some embodiments, PCB 206 may be any other suitable substrate for mounting a packaged electronic device. Bottom heat spreader 202 may be in thermal communication with cooling solution 208 via thermal interface material 209 and / or other gap filling materials. In some embodiments, cooling solution 208 may be a heat sink. In some embodiments, cooling solution 208 may include fins. In some embodiments, cooling solution 208 may be a cold plate or another suitable cooling solution.

[0066] In some embodiments, the thicknesses of the top heat spreader and the bottom heat spreader can be improved or optimized using the equation Q = mcΔT, where Q is the absorbed energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. Thus, for example, in the case of a dual heat spreader arrangement, the total absorbed heat is Q = m t ct ΔT t +m b c b ΔT b can be provided by. In this specification, the subscript t indicates the top heat spreader, and the subscript b indicates the bottom heat spreader. When the top and bottom heat spreaders are made of the same material, since c t and c b are the same, the formula can be simplified. In some embodiments, to achieve a specific total energy absorption, the mass, mass ratio (e.g., the mass of the top heat spreader relative to the bottom heat spreader) can be improved or optimized by at least partially considering the initial and target maximum temperatures. In some embodiments, the geometric and / or spatial optimization can be performed using simulations, such as 3D transient heat simulations.

[0067] In this specification, the top and bottom are used to indicate that the heat spreaders are mainly on both sides of the die. In some embodiments, the "top" side may be the side closest to the PCB, but in some embodiments, the top side may face outward from the PCB. The top heat spreader may also be referred to as a lead frame or a PCB lead frame. The bottom heat spreader may also be referred to as a die paddle.

[0068] In some embodiments, the bottom heat spreader (e.g., the bottom plate) may face outwardly away from the PCB and may be designed to interface with a cold plate or heat sink that may be at a lower temperature than the PCB. In some embodiments, the bottom heat spreader may be a primary thermal reservoir having a lower temperature, e.g., during steady-state operation. Thus, the bottom heat spreader may be proportionally larger than the top heat spreader (e.g., the top plate), which may be primarily designed to address rapid heat demands due to surge loads. The ratio of the top heat spreader to the bottom heat spreader may be adjusted to absorb transient heat loads to enable higher overall energy absorption within defined parameter limits (e.g., a maximum die temperature limit sustainable over a given period). The bottom heat spreader and the top heat spreader may additionally or alternatively be balanced or otherwise designed to reduce the temperature gradient near the die during high-load events.

[0069] As described above, the top heat spreader may be arranged to address rapid heat absorption when an instantaneous surge load is applied to the die, resulting in heat generation beyond steady-state operation. The top heat spreader may be soldered or sintered to the die and may be substantially thicker than commonly used to facilitate electrical conduction with the PCB. For example, the top and bottom heat spreaders may have a thickness of about 1 mm, 2 mm, about 3 mm, about 4 mm, or about 5 mm, or any thickness between these values, or may be made thicker as needed.

[0070] FIG. 4 depicts an exploded view of a package for two semiconductor devices with double-sided cooling according to some embodiments. As will be described in more detail below, in some embodiments, the semiconductor device package can be manufactured in a face-to-face configuration as depicted in FIG. 4, although it will be understood that such a manufacturing process is not necessary. The semiconductor device package can include a PCB lead frame 402 (also referred to as a lead frame), solder 404, a thermistor 406, solder 408, a die clip 410, solder 412, a die 414, solder 416, and a die paddle 418. As shown in FIG. 4, solder 416 is used to attach die 414 to die paddle 418, which can be, for example, a copper block, an AlN block, or other material having desirable electrical and heat conduction properties. Die paddle 418 can be a bottom heat spreader. Die clip 410 can be attached to the side of die 414 opposite die paddle 418 using solder 412. Die clip 410 can be thin. Die clip 410 can reduce the drain and source loop inductance and associated losses. Lead frame 402 can be soldered to die clip 410 using solder 404. Lead frame 402 can be an upper heat spreader. In some embodiments, the semiconductor device package can include other active dies or passive dies. For example, passive die 406 can be a thermistor attached to die clip 410 using solder 408.

[0071] FIG. 5 is a side view of a semiconductor device package with double-sided cooling according to some embodiments. The semiconductor device package may include a lead frame 402, a passive die 406, a die clip 410, a die 414, and a die paddle 418. The illustrated components may be fixed to each other by solder, for example, as shown in FIG. 4. For simplicity, the solder is omitted from FIG. 5. The semiconductor device package may include a heat spreader 506 that is in thermal contact with the die paddle 418 via a thermal interface material 508. The heat spreader may be a cold plate, a heat sink, or any other suitable cooling solution. The semiconductor device package may be disposed on a PCB 502 having copper contact pads 504 disposed therein. The die paddle 418 may operate as a drain contact for the die 414 and may be fixed to the contact pads 504 (e.g., copper contact pads), and the die 414 may be disposed thereon by soldering, for example, as shown in FIG. 4. The die clip 410 may be used to provide a source contact of the semiconductor device and may be in electrical and thermal contact with the second copper pad 504 on the PCB 502 and the upper surface of the die 414. The heat spreader 506 may be disposed in thermal contact with the die clip 410. In some embodiments, a passive die 406 (e.g., a thermistor) may be disposed on the die clip 410 to monitor the temperature of the semiconductor device. A thermal interface material 508 may be used to dispose the die paddle 418 in thermal contact with the heat spreader 506. In some embodiments, the heat spreader 506 may be present outside the semiconductor device package. In some embodiments, the heat spreader 506 may be part of the semiconductor device package. For example, the heat spreader 506 may have an outward-facing surface disposed on or near the outer surface of the semiconductor device package.

[0072] FIG. 5 shows arrows indicating paths through which heat can be transported away from the die. For example, heat can flow through the die clip 410, through the contact pad 504, and into the PCB 502. Heat can flow through the lead frame 402, to the contact pad 504, and then to the PCB 502. Heat can flow through the die paddle 418 and the thermal interface material 508 to the heat spreader 506.

[0073] In the system of FIG. 5, the die 414 can be a high-power die arranged for operation at 1 kV or more (e.g., 1200V operation). The die can include power switches and / or other components.

[0074] In FIG. 5, one die is shown between the die paddle and the heat spreader, but in some other applications, two or more dies can be included between the die paddle and the heat spreader. In such applications, the two or more dies can be in electrical communication and / or thermal communication with each other.

[0075] It will be understood that FIG. 5 is merely an example and that other embodiments are possible. For example, in some embodiments, neither the die paddle nor the clip need be used to provide electrical contact, or additional or alternative contacts may be provided. If contacts are provided, they may be designed to improve electrical characteristics. For example, source and drain connections may be closely nested to reduce parasitic inductance. In some embodiments, the lead frame can be capable of mounting the heat spreader.

[0076] Placing a die between two thermally expansive materials (e.g., a thermally expansive die paddle and a thermally expansive heat spreader or lead frame) presents several challenges. Metals used for electrical contact and heat transfer can expand significantly when heated. For example, copper can expand at about 17 ppm / °C in certain applications. Thermal expansion can introduce stress to the die. Thus, in some embodiments, the die may be placed at the center of the paddle and / or heat spreader (or lead frame) to reduce or minimize stress non-uniformities that may damage the die.

[0077] FIG. 6 illustrates another exemplary embodiment of a package for a semiconductor device according to some embodiments of the present disclosure. The embodiment of FIG. 6 is generally similar to the embodiment of FIG. 5. In FIG. 6, the bottom heat spreader 418' (also referred to as a die paddle) may have a different structure from the bottom heat spreader of FIG. 5. For example, in FIG. 5, the die paddle 418 is directly electrically connected to the contact pads of the PCB. In FIG. 6, the bottom heat spreader 418' is not directly electrically connected to the contact pads of the PCB. In FIG. 6, the die is placed on a thermally expansive die paddle, and the top surface of the die is in contact with a clip. A heat spreader is in contact with the clip. As shown in FIG. 6, heat may flow from the die to the paddle and ultimately to the PCB through pads (e.g., copper pads). Heat may also flow from the die to the clip, to the heat spreader, and ultimately to the heat sink simultaneously by crossing a thermal interface material that may have a wide range of thermal conductivities. Additionally, some thermal energy may move along the clip and ultimately to the PCB through pads (e.g., copper pads) in contact with the clip.

[0078] FIG. 7 illustrates the heat transfer paths of a semiconductor device assembly according to some embodiments of the present specification. As shown in FIG. 7, two primary paths for carrying heat away from the die are provided. Heat may be transported from the die to the PCB, from the die through the die attach solder to the die paddle, to the pad (e.g., copper pad) to which the device package is mounted, and ultimately to the PCB. Alternatively or additionally, heat may move from the die through the clip-to-die solder, through the die clip, through the lead solder, and into the lead frame. Heat may leave the lead frame and be carried to the heat sink from outside the device package through the thermal interface material.

[0079] The arrangement depicted in FIG. 7 enables heat to be carried away from the die in two directions with relatively high efficiency. Advantageously, since the thermal interface material can be a thermal bottleneck, a large thermal mass contacts the die without using a thermal interface material (e.g., thermal paste or pad). Thermal interface materials typically have a higher thermal impedance compared to metals. Die attach bonding compounds such as solder, sintered paste, and epoxy may exhibit significantly higher thermal conductivity and lower interface impedance than typical thermal interface materials. For example, solder may have a thermal conductivity of at least about 20 W / m·K, 50 W / m·K, or 80 W / m·K or more, depending on the solder. A typical dielectric and electrically insulating thermal interface material may have a thermal conductivity of less than about 10 W / m·K, although some special materials may achieve a somewhat higher thermal conductivity.

[0080] Figures 4 - 7 depict the die clip as a separate component from the heat spreader, although in certain embodiments the die clip and heat spreader may be a single integrated component. In some embodiments, the heat spreader and die clip may be separate components. In some embodiments, the heat spreader and clip may be pre - joined. In some embodiments, the die clip may be a sheet metal clip and may be folded to function as a stepped region of double thickness for die connection and as a heat spreader. As described above, in some embodiments, the die clip may have a thermistor fixed, for example, by soldering. In some embodiments, simplification of the manufacturing process of the packaged semiconductor device is possible, for example, by reducing the number of reflow steps in the manufacturing process, by pre - joining the die clip and heat spreader or by forming the die clip and heat spreader as a single component.

[0081] In some embodiments, the contact pads and / or other features on the PCB may be shaped, sized, and arranged to promote lateral heat transfer and electrical conduction on the thermally conductive PCB plane, and the thermal diffusion effect may be utilized to carry heat away from the device package. In some embodiments, the PCB may include thermal vias that can be used to transport heat to the underlying PCB plane.

[0082] In some embodiments, the contacts external to the semiconductor device package may be positioned to reduce or minimize surface discharge. For example, in some high-power applications, the device may experience a source and drain potential drop of about 1 kV or more, which can lead to a substantial surface discharge distance. Thus, the source lead 804 and the drain lead 802 may be held apart by a significant distance, such as about 4 mm, 5 mm, or 6 mm or more, as depicted in FIG. 8. In some embodiments, the contacts may be spaced as far apart as possible without increasing the package size beyond acceptable limits. In some embodiments, surface mount device (SMD) epoxy grooves 806 may be used to direct the flow path for forming a curved epoxy pattern and provide lower high-voltage insulation between the features of the component assembly and the PCB. Design and Manufacture of Dual Heat Spreader

[0083] Preferably, a semiconductor package with double-sided cooling can be manufactured using prior art techniques to minimize cost and / or improve yield. Thus, for example, while a relatively thick heat spreader may be desirable for cooling, the thickness of the heat spreader may be limited, for example, to about 3 mm or less so that metal components such as the lead frame of the semiconductor package can be manufactured using an open-reel manufacturing process.

[0084] In some embodiments, the dual heat spreaders can each be manufactured from a single profiled copper strip using stamping, corner bending, cutting, and / or other manufacturing techniques. In some embodiments, the dual heat spreaders may be fixed to a thin punched frame to improve manufacturing efficiency and enable other forming processes such as cold or hot forging, and optionally allow for open-reel manufacturing.

[0085] As shown in FIG. 9, profiled copper 902, 904 (or another suitable material) may be used to fabricate the lead frame and die paddle. For example, profiled copper 902 may have a lead frame profile, and profiled copper 904 may have a die paddle profile. A typical manufacturing process may be able to add grooves, recesses, etc. that may be desirable in the finished shapes 906, 908, 910 without the need to remove large amounts of material, but can lead to delays and / or complications in the manufacturing process. For example, the finished shape may include a lead frame 906, a die clip 908, and / or a die paddle 910.

[0086] The approach depicted in FIG. 9 has several advantages, but manufacturing challenges may still exist. For example, to manufacture individual semiconductor die packages, after molding, there is still a need to singulate the shape into individual components by cutting, sawing, dicing, or other methods, and cutting thick copper, while having other disadvantages, can significantly delay the manufacturing process. Thus, in some embodiments, as shown in FIG. 10, a thick metal component may be hot forged and then attached to a lightweight thin frame. In FIG. 10, die paddle 418 is riveted to carrier frame 1002. Additional embodiments

[0087] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, it will be apparent that various modifications and changes may be made without departing from the broader spirit and scope of the disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a limiting sense.

[0088] Indeed, while the present disclosure is in the context of specific embodiments and examples, those skilled in the art will understand that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and / or uses of the invention and its equivalents. Further, although some variations of the embodiments have been shown and described in detail, other variations within the scope of the present disclosure will be readily apparent to those skilled in the art based on the present disclosure. Also, various combinations or sub - combinations of the specific features and aspects of the embodiments may be made and are still considered to be within the scope of the present disclosure. It should be understood that the various features and aspects of the disclosed embodiments may be combined with or replaced by each other to form various forms of the disclosed embodiments. None of the methods disclosed herein need be performed in the order recited. Accordingly, it is intended that the scope of the present disclosure should not be limited by the specific embodiments described above.

[0089] Each of the systems and methods of the present disclosure has several innovative aspects, and it should be understood that none of them, even alone, is responsible for or required to have the desirable attributes disclosed herein. The various features and steps described above may be used independently of each other or combined in various ways. All possible combinations and sub - combinations are intended to fall within the scope of the present disclosure.

[0090] The specific features described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, the various features described in the context of a single embodiment may be implemented separately or in any suitable sub - combination in multiple embodiments. Further, features may be described and initially claimed as acting in a particular combination, but one or more features from the claimed combination may, in some cases, be deleted from the combination, and the claimed combination may be directed to a sub - combination or a variation of a sub - combination. None of the single features or groups of features are necessary or essential to each embodiment.

[0091] Phrases used herein to describe conditions, such as, among others, "can", "could", "might", "may", "e.g.", etc., generally, unless otherwise specified or understood in a different sense within the context in which they are used, are intended to convey that a particular embodiment includes a particular feature, element and / or step, while other embodiments do not. Thus, such phrases used to describe conditions are generally not intended to mean that a feature, element and / or step is required in any way in one or more embodiments, or that one or more embodiments necessarily include logic for determining whether these features, elements and / or steps are included in or should be performed in any particular embodiment, regardless of author input or prompting. Terms such as "comprising", "including", "having", etc. are synonyms and are used in an inclusive, unrestricted manner and do not exclude additional elements, features, acts, operations, etc. Further, the term "or" is used in an inclusive sense (not an exclusive sense), so that, for example, when used to connect a list of elements, the phrase "or" means one, some, or all of the elements in the list. Further, the articles "a", "an", and "the" used in this application and the appended claims should be construed to mean "one or more" or "at least one" unless otherwise specified. Similarly, operations may be depicted in the drawings in a particular order, but it should be recognized that such operations need not be performed in the particular order or sequential order shown to achieve the desired result, or that all of the operations shown need not be performed. Further, the drawings may schematically depict additional exemplary steps in the form of a flowchart. However, other operations not depicted may be incorporated into the exemplary methods and steps schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously with, or during any of the operations shown.Furthermore, the operations may be rearranged or reordered in other embodiments. In certain circumstances, multitasking and parallel processing may be advantageous. Additionally, the separation of various system components in the above-described embodiments should not be understood to require such separation in all embodiments, and the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products. Further, other embodiments are within the scope of the following claims. In some cases, the acts recited in the claims may be performed in a different order and still achieve desirable results.

[0092] Furthermore, the methods and apparatuses described herein may be susceptible to various modifications and alternative forms, and specific examples thereof are shown in the drawings and described in detail herein. However, the present disclosure is not limited to the specific forms or methods disclosed, but on the contrary, the present disclosure is intended to cover all modifications, equivalents, and alternatives within the spirit and scope of the various implementation examples described and the appended claims. Additionally, any disclosure herein of any specific feature, aspect, method, property, characteristic, quality, attribute, element, etc. related to an implementation example or embodiment may be used in any of the other implementation examples or embodiments described herein. Any method disclosed herein need not be performed in the order recited. The methods disclosed herein may include specific acts taken by an implementer. However, the methods may also implicitly or explicitly include any third-party orders of those acts. The scope disclosed herein also encompasses any and all overlaps, subranges, and combinations thereof. Phrases such as "up to," "at least," "greater than," "less than," "between," etc. include the recited numbers. Numbers preceded by terms such as "about" or "approximately" include the recited numbers and should be interpreted based on the circumstances (e.g., as accurate as reasonably possible in that circumstance, ±5%, ±10%, ±15%, etc.). Terms such as "substantially" preceding a phrase include the recited phrase and should be interpreted based on the circumstances (e.g., as reasonably possible in that circumstance). For example, "substantially constant" includes "constant." Unless otherwise stated, all measurements are made under standard conditions including temperature and pressure.

[0093] As used herein, the phrase "at least one of" in a list of items refers to any combination of those items, including a single member. By way of example, "at least one of: A, B, or C" is intended to include A, B, C, A and B, A and C, B and C, and A, B, and C. Conjunctive language such as the phrase "at least one of X, Y and Z" is generally understood in the context in which it is used, unless otherwise specified, to convey that an item, term, etc. may be any one or more of X, Y, or Z. Thus, such conjunctive language is not generally intended to mean that in a particular embodiment, at least one of X, at least one of Y, and at least one of Z must each be present. Headings provided herein are for convenience only and do not necessarily affect the scope or meaning of the apparatus and methods disclosed herein, even if any are provided.

[0094] Accordingly, the claims are not intended to be limited to the embodiments shown herein, but rather are to be accorded the widest scope consistent with the disclosure, principles, and novel features disclosed herein.

[0095] It should be understood that although the claims presented herein are in single dependent form, any claim may depend on any preceding claim of the same type, except where it is clearly technically infeasible.

Claims

1. 1. An apparatus with double-sided surge power heat sinking, comprising: a semiconductor die; a bottom heat spreader configured as an electrical contact for the semiconductor die; a top heat spreader; a circuit board, the bottom heat spreader being disposed between the circuit board and the semiconductor die; a printed circuit board, the bottom heat spreader positioned between the printed circuit board and the semiconductor die; Equipped with the bottom heat spreader and the top heat spreader are disposed on opposite sides of the semiconductor die; an area of ​​the top heat spreader greater than an area of ​​the semiconductor die, the top heat spreader extending beyond the semiconductor die; an area of ​​the bottom heat spreader greater than an area of ​​the semiconductor die, the bottom heat spreader extending beyond the semiconductor die; the combined thickness of the top heat spreader and the bottom heat spreader is at least four times the thickness of the semiconductor die.

2. The device described in claim 1, wherein the top heat spreader has at least one electrical contact.

3. The device described in claim 1, further comprising a clip configured as a second electrical contact for the semiconductor die, the clip being positioned on the same side of the semiconductor die as the top heat spreader and configured to be in electrical and thermal contact with the semiconductor die, the clip being positioned between the semiconductor die and the top heat spreader.

4. The device of claim 3 further comprising a thermistor or other passive die disposed on the clip.

5. 10. The device of claim 1, wherein both the bottom heat spreader and the top heat spreader are soldered to the semiconductor die.

6. The device of claim 1 , wherein at least one of the top and bottom heat spreaders comprises copper.

7. 10. The apparatus of claim 1, wherein the semiconductor die is positioned between the top and bottom heat spreaders so as to have a substantially neutral position for symmetrical thermal expansion.

8. 2. The device of claim 1, wherein the top heat spreader has a thickness greater than 1 mm and the bottom heat spreader has a thickness greater than 1 mm.

9. 2. The device of claim 1, wherein the top heat spreader has a thickness greater than 3 mm and the bottom heat spreader has a thickness greater than 3 mm.

10. 10. The apparatus of claim 1, wherein the top heat spreader and the bottom heat spreader are both configured to maintain the semiconductor die at a temperature below 160 degrees when subjected to a surge load of up to 100 W from steady state for up to 0.5 seconds.

11. 1. An apparatus with double-sided surge power heat sinking, comprising: a semiconductor die; a bottom heat spreader in thermal communication with the semiconductor die; a top heat spreader in thermal communication with the semiconductor die; the bottom heat spreader and the top heat spreader are disposed on opposite sides of the semiconductor die; wherein the bottom heat spreader and the bottom heat spreader together are configured to maintain the semiconductor die at a temperature below 160 degrees when subjected to a surge load of up to 100 W from steady state for up to 0.5 seconds.

12. 12. The apparatus of claim 11, wherein the top heat spreader and the bottom heat spreader are both configured to maintain the semiconductor die at a temperature below 200 degrees when subjected to a surge load of up to 100 W from steady state for up to 1 second.

13. 12. The apparatus of claim 11, further comprising a clip disposed on the same side of the semiconductor die as the top heat spreader and configured to be in electrical and thermal contact with the semiconductor die, the clip being positioned between the semiconductor die and the top heat spreader.

14. The device of claim 13 further comprising a thermistor or other passive die disposed on the clip.

15. The device of claim 1, further comprising a cooling solution in thermal contact with the bottom heat spreader.

16. 16. The apparatus of claim 15, wherein the bottom heat spreader is configured to electrically and thermally connect to at least one contact pad of a printed circuit board, and the top heat spreader is configured to be in thermal communication with a heat sink.

17. 17. The apparatus of claim 16, wherein the top heat spreader is electrically and thermally connected to a contact pad of the printed circuit board that is separate from the at least one contact pad.

18. The apparatus of claim 15 , wherein the cooling solution comprises a heat sink.

19. The device described in claim 3, wherein the clip comprises folded or formed sheet metal.

20. The device described in claim 1, further comprising a clip providing a source contact electrically connected to a source of the semiconductor field effect transistor, the clip positioned between the semiconductor die and the top heat spreader.

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