Double-sided cooling power module

Abstract

According to the present invention, a double-sided cooling type power supply module includes: an upper substrate, which includes an insulating layer, an upper metal layer and a lower metal layer, the upper metal layer is bonded to the top of the insulating layer, and the lower metal layer is bonded to the bottom of the insulating layer; a lower substrate, which is arranged below the upper substrate and includes an insulating layer, an upper metal layer and a lower metal layer, the upper metal layer is bonded to the top of the insulating layer, and the lower metal layer is bonded to the bottom of the insulating layer; a spacer, which is arranged between the upper substrate and the lower substrate and electrically connects the upper substrate and the lower substrate; and a semiconductor chip, which is arranged between the spacer and the upper substrate or between the spacer and the lower substrate, wherein the insulating layer is made of a material whose thermal expansion coefficient is 0.8 times or more and 1.2 times or less than the thermal expansion coefficient of the metal layers of the upper substrate and the lower substrate.

Description

Technical Field

[0001] The present invention relates to a double-sided cooling type power supply module, which can have improved heat dissipation characteristics and durability. Background Art

[0002] Inverters are attracting attention as components for driving environmentally friendly vehicles (hybrid and electric vehicles). Power modules are one of the components that contribute the majority of inverter manufacturing costs, and much research has been conducted to increase power output, reduce size, and lower manufacturing costs. Furthermore, research is actively underway into double-sided cooling power modules to reduce size and improve cooling efficiency.

[0003] A double-sided cooled power module includes multiple semiconductor chips between a top substrate and a bottom substrate and is configured so that heat from the semiconductors is removed by coolers arranged outside the two substrates, thereby reducing the size of the power module and improving cooling efficiency.

[0004] like Figure 1 As shown, a conventional power module has a stacked structure of an insulating substrate, a spacer, and an insulating substrate, wherein the components are joined by solder. To improve the durability of the stacked structure of the power module, it is necessary to minimize the difference in the coefficient of thermal expansion (CTE) between the materials.

[0005] By using a ceramic insulating substrate in conventional power modules, the CTE of the copper pattern surface can be reduced by the ceramic, resulting in a CTE of 9.14, compared to 16.5 for copper. Metal matrix composites (MMC) are used to reduce the CTE between materials, but MMC is relatively expensive due to its difficult manufacturing methods. Furthermore, MMC has a lower CTE but poor thermal conductivity, which limits the thermal characteristics of the power module.

[0006] For this reason, it is necessary to develop materials and structures for power modules that can improve the balance of CTEs in a stacked structure of the power modules and improve thermal characteristics of the power modules. Summary of the Invention

[0007] In a preferred aspect, a double-sided cooling type power module is provided, which can have an improved CTE balance and improved thermal characteristics.

[0008] In one aspect, a double-sided cooling power module is provided, which may include: i) an upper substrate including a first insulating layer, a first upper metal layer, and a first lower metal layer, the first upper metal layer being bonded to the top of the first insulating layer and the first lower metal layer being bonded to the bottom of the first insulating layer; ii) a lower substrate disposed below the upper substrate and including a second insulating layer, a second upper metal layer, and a second lower metal layer, the second upper metal layer being bonded to the top of the second insulating layer and the second lower metal layer being bonded to the bottom of the second insulating layer; iii) a spacer disposed between the upper and lower substrates and electrically connecting the upper and lower substrates; and iv) a semiconductor chip disposed between the spacer and the upper substrate or between the spacer and the lower substrate. In particular, each of the first and second insulating layers may include a material having a thermal expansion coefficient that is approximately 0.8 times or greater and approximately 1.2 times or less than the thermal expansion coefficient of the first and second upper metal layers of the upper substrate and the second and second lower metal layers of the lower substrate.

[0009] The spacer, the first upper metal layer and the first lower metal layer of the upper substrate, and the second upper metal layer and the second lower metal layer of the lower substrate may be made of the same material.

[0010] The spacer may include a metal material having a thermal conductivity of about 300 W / mK or greater.

[0011] Each of the first and second insulating layers may include a resin material having a thermal expansion coefficient of about 13 or more and a Young's modulus of about 50 GPa or less.

[0012] Each of the first insulating layer and the second insulating layer may include a resin material having a thermal conductivity of about 15 W / mK or greater and a thickness of about 0.2 mm or less.

[0013] The resin material may include one or more selected from the group consisting of aluminum oxide (Al 2 O 3 ), boron nitride (BN), and aluminum nitride (AlN).

[0014] Preferably, the content of boron nitride may be greater than the content of aluminum oxide and / or aluminum nitride.

[0015] The thermal expansion coefficients of the surfaces of the upper substrate and the lower substrate can be derived from the following formula.

[0016] [formula]

[0017] The CTE of the substrate surface = CTE of the insulating layer + (CTE of the metal layer - CTE of the insulating layer) × {2 × Young's modulus of the metal layer × thickness of the metal layer / (2 × Young's modulus of the metal layer × thickness of the metal layer + Young's modulus of the insulating layer × thickness of the insulating layer)}.

[0018] The thickness of the first upper metal layer and the first lower metal layer of the upper substrate, the second upper metal layer and the second lower metal layer of the lower substrate, and the spacer can be the same, and the thickness of each of the first upper metal layer and the first lower metal layer of the upper substrate, the second upper metal layer and the second lower metal layer of the lower substrate, and the spacer can be greater than the thickness of each of the first insulating layer and the second insulating layer.

[0019] The first cooler may be disposed on an outer side of the first upper metal layer of the upper substrate, and the second cooler may be disposed on the second lower metal layer of the lower substrate.

[0020] A thermal interface material (TIM) may be disposed between the first upper metal layer and the first cooler and / or between the second lower metal layer of the lower substrate and the second cooler.

[0021] The first upper metal layer and the first lower metal layer of the upper substrate, the second upper metal layer and the second lower metal layer of the lower substrate, and the spacer may include a copper material.

[0022] A thickness of each of the first upper and lower metal layers of the upper substrate, the second upper and lower metal layers of the lower substrate, and the spacer may be about 0.5 mm or more.

[0023] A vehicle is further provided, which may include the double-sided cooling power module described herein.

[0024] The double-sided cooling type power module according to various exemplary embodiments of the present invention has the following effects.

[0025] By using the spacer made of a copper material, heat dissipation performance can be improved, thereby reducing manufacturing costs compared to a conventional power module using MMC as a material for the spacer.

[0026] Furthermore, since the insulating layer is disposed in the power module, heat discharge performance is high and the cooler can be easily mounted, so that the convenience of assembly can be improved.

[0027] In addition, since resin-based insulating layers (such as the first insulating layer and the second insulating layer) with a low thermal expansion coefficient are used in the insulating substrate, a pattern of copper material with a thickness of 0.5 mm or more can be applied, so that the heat discharge area can be increased and the heat discharge characteristics can be improved.

[0028] Furthermore, since the resin-based insulating layers (the first insulating layer and the second insulating layer) are used, the resin-based insulating layers can absorb vibrations generated by pressing when the cooler is bonded to the upper and lower substrates, thereby improving stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other aspects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A schematic diagram illustrating the structure of a double-sided cooling power module of the prior art is shown;

[0031] Figure 2 shows a schematic diagram illustrating the structure of an exemplary double-sided cooling type power module according to an exemplary embodiment of the present invention;

[0032] Figure 3 A table showing differences in materials, properties, thicknesses, and CTEs of components in an exemplary double-sided cooling type power module according to an exemplary embodiment of the present invention and a conventional power module is shown. DETAILED DESCRIPTION

[0033] The specific structural or functional description of the exemplary embodiments of the present invention disclosed in the specification or application is provided only for the purpose of describing the embodiments according to the present invention. Therefore, the exemplary embodiments according to the present invention can be implemented in various ways, and the present invention should not be interpreted as being limited to the exemplary embodiments described in the specification or application.

[0034] Various changes and modifications may be made to the embodiments according to the various exemplary embodiments of the present invention, and therefore specific embodiments will be shown in the drawings and described in the specification or application. However, it should be understood that the embodiments conceived according to the present invention are not limited to the specific disclosed embodiments, but the present invention includes all modifications, equivalents and alternatives that fall within the spirit and scope of the present invention.

[0035] Although terms such as first, second, etc. may be used to describe various elements, the elements should not be limited by these terms. These terms are only used to distinguish one element from another, and thus, without departing from the scope of protection of the present invention, a first element may be named a second element, and a second element may be similarly named a first element.

[0036] When an element is referred to as being "connected" or "accessed" to another element, it should be understood that not only is the element directly connected or accessed to the other element, but another element may also be present between them. Conversely, when a component is referred to as being "directly connected" or "directly accessed" to another component, it should be understood that there is no component between them. Other expressions describing the relationship between structural elements, namely, "between" and "only between" or "adjacent" and "directly adjacent", should be interpreted similarly to the above description.

[0037] In this specification, terms are used only to describe specific embodiments and are not intended to limit the present invention. As used herein, the singular is intended to include the plural, unless the context clearly indicates otherwise. In the specification, it should be understood that the terms "comprise," "include," or "have" represent the presence of features, numbers, steps, operations, structural elements, parts, or combinations thereof, and do not preclude the presence or possibility of adding one or more other features, numbers, steps, operations, structural elements, parts, or combinations thereof.

[0038] Unless otherwise indicated, all numbers, values ​​and / or expressions relating to ingredients, reaction conditions, polymer compositions and formulations used herein should be understood as being modified in all instances by the term "about" since such numbers are approximate in nature and reflect, among other things, the various measurement uncertainties encountered in obtaining such values.

[0039] Further, unless otherwise stated or apparent from the context, the term "about" as used herein is understood to mean within the normal tolerance range in the art, for example, within 2 standard deviations of the mean. "About" can be understood to mean within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless the context clearly indicates otherwise, all numerical values ​​provided herein are modified by the term "about."

[0040] It should be understood that the term "vehicle" or "vehicular" or other similar terms used herein generally include motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, ships including various boats, marine vessels, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petroleum energy sources). As referred to herein, a hybrid vehicle is a vehicle that has two or more power sources, such as both gasoline-powered and electric-powered vehicles.

[0041] Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by those skilled in the art in the art to which this invention pertains. It should be understood that these terms are the same as those defined in common dictionaries and have the same meaning as in the context of the relevant art. Unless otherwise explicitly defined, these terms should not be ideally or excessively interpreted as having a formal meaning.

[0042] Hereinafter, the present invention will be described in detail by describing exemplary embodiments of the present invention with reference to the accompanying drawings. The same reference numerals given in the drawings indicate the same components.

[0043] Figure 2 A schematic diagram illustrating the structure of an exemplary double-sided cooling type power module according to an exemplary embodiment of the present invention is shown.

[0044] like Figure 2 As shown, a double-sided cooling type power module according to an exemplary embodiment of the present invention may include an upper substrate 100, a lower substrate 200, a semiconductor chip 300, a spacer 400, and a cooler 500, and specifically has a stacked structure of the lower substrate 200, the semiconductor chip 300, the spacer 400, and the upper substrate 100. In a double-sided cooling type power module having such a stacked structure, the components can be bonded and stacked by adhesives on the top and bottom of the components.

[0045] The double-sided cooling type power module according to the exemplary embodiment of the present invention may be a power module for an inverter of a hybrid vehicle and an electric vehicle, in which cooling performance can be improved by discharging heat in two directions.

[0046] In detail, the upper substrate 100 of the double-sided cooling type power module according to the present invention may include a first insulating layer 110, a first upper metal layer 120 and a first lower metal layer 130, the first upper metal layer 120 is bonded to the top of the first insulating layer 110, and the first lower metal layer 130 is bonded to the bottom of the first insulating layer 110.

[0047] The lower substrate 200 may be arranged below the upper substrate 100 and may include a second insulating layer 210 , a second upper metal layer 220 and a second lower metal layer 230 , wherein the second upper metal layer 220 is bonded to the top of the second insulating layer 210 and the second lower metal layer 230 is bonded to the bottom of the second insulating layer 210 .

[0048] In the present invention, the upper substrate and the lower substrate can have such a structure: wherein the metal layers (i.e., the first upper metal layer 120, the first lower metal layer 130, the second upper metal layer 220 and the second lower metal layer 230) can be arranged on both sides of the insulating layer (i.e., the first insulating layer and the second insulating layer) to form a substrate, such as the direct bonded copper (DBC) substrate in the prior art.

[0049] The semiconductor chip 300 may be disposed between the upper substrate 100 and the lower substrate 200. For example, the semiconductor chip 300 may be disposed on the upper metal layer 220 of the lower substrate 200.

[0050] The spacer 400 may be disposed between the upper substrate 100 and the lower substrate 200 and electrically connect the upper substrate 100 and the lower substrate 200 .

[0051] The cooler 500 may be disposed on the outer side of the first upper metal layer 120 of the upper substrate 100 and the outer side of the second lower metal layer 230 of the lower substrate 200. For example, the first cooler 500 (top 500) may be disposed on the first upper metal layer 120 of the upper substrate 100, and the second cooler 500 (bottom 500) may be disposed on the second lower metal layer 230 of the lower substrate 200.

[0052] Hereinafter, materials and characteristics of components of a double-sided cooling type power module according to an exemplary embodiment of the present invention for improving balance of thermal expansion coefficients and thermal characteristics of the power module having the above structure are described in more detail.

[0053] In the double-sided cooling power module according to the exemplary embodiment of the present invention, the spacer 400 can be made of or include a metal material having a thermal conductivity exceeding approximately 300 W / mK. For example, the spacer 400 can be made of or include a copper material. The spacer 400 can be made of the same material as the metal layers (upper metal layers 120, 220 and lower metal layers 130, 230) of the upper substrate 100 and the lower substrate 200. Preferably, the metal layers of the upper substrate 100 and the lower substrate 200 can be made of copper.

[0054] In the prior art, metal matrix composites (MMC) including AlSiC, CuMo, CuC, etc. have been used to reduce the differences in the thermal expansion coefficients of the components of the power module. However, there is a problem that MMC is expensive due to the difficulty in manufacturing, and has a low thermal expansion coefficient and poor thermal conductivity, so the thermal characteristics of the power module are deteriorated.

[0055] As described above, using copper, a material less expensive than MMC, for the spacer according to an exemplary embodiment of the present invention can reduce manufacturing costs and minimize the difference in thermal expansion coefficient between the spacer and the insulation layer. Consequently, stress concentration in specific areas during temperature cycling can be prevented, thereby improving the durability of the entire power module. Furthermore, the high thermal conductivity of copper improves the overall thermal characteristics of the power module.

[0056] The insulating layers 110 and 210 may be made of or include a material having a thermal expansion coefficient of about 0.8 times or more and about 1.2 times or less than the thermal expansion coefficients of the metal layers 120 and 130 of the upper substrate 100 and the metal layers 220 and 230 of the lower substrate 200. Since the metal layers of the substrates and the spacers are made of the same material in the present invention, the insulating layers 110 and 210 may be made of or include a material having a thermal expansion coefficient of about 0.8 times or more and about 1.2 times or less than the thermal expansion coefficient of the spacer 400. For example, since the thermal expansion coefficient of copper is about 16.5 pp / K, when the spacer 400 is made of copper, the thermal expansion coefficients of the insulating layers 110 and 210 may be about 16.5×0.8 or more and about 16.5×1.2 or less.

[0057] The insulating layers 110 and 210 of the substrate may be made of or include a resin material having a thermal expansion coefficient of about 13 or greater and a Young's modulus of about 50 GPa or less, so that the thermal expansion coefficient of the insulating layers 110 and 210 may be about 0.8 to 1.2 times the thermal expansion coefficient of the spacer 400.

[0058] Furthermore, in order to ensure thermal characteristics of the insulating layer, the first and second insulating layers 110 and 210 of the substrate may be made of a resin material having a thermal conductivity of about 15 W / mK or more and a thickness of about 0.2 mm or less.

[0059] Preferably, the resin material may include one or more selected from the group consisting of aluminum oxide (Al2O3), boron nitride (BN), and aluminum nitride (AlN). The resin material may contain more boron nitride than aluminum oxide and aluminum nitride. The content of boron nitride may be greater than the content of aluminum oxide and / or aluminum nitride.

[0060] According to a specific embodiment of the present invention, the thermal expansion coefficient of the first insulating layer 110 and the second insulating layer 210 of the substrate is set to about 0.8 times to 1.2 times the thermal expansion coefficient of the spacer 400. The reason is that the stress according to the temperature cycle is minimized by minimizing the difference in thermal expansion coefficient between the insulating layers 110, 210 and the spacer arranged on the surface of the insulating substrate, thereby improving the durability of the power module.

[0061] When the difference in thermal expansion coefficient between the spacer and the insulation layer is significant, stress concentrates on the top of the semiconductor chip during temperature cycling, potentially cracking the solder on the chip and reducing the durability of the power module. To address this issue, the present invention minimizes the difference in thermal expansion coefficient by using a material with a thermal expansion coefficient of approximately 0.8 to 1.2 times or less that of the spacer for the insulation layer. This prevents stress concentration on specific portions of the top and bottom of the chip during temperature cycling, improving the durability of the entire power module.

[0062] The thickness of the metal layer (the first upper metal layer 120, the first lower metal layer 130, and the second upper metal layer 220, the second lower metal layer 230) of the substrate and the thickness of the spacer can be the same. For example, as described above, the metal layer and the spacer can be made of or include a copper material, and the thickness of the metal layer and the thickness of the spacer can be about 0.5 mm or greater. The thickness of each of the metal layer (the first upper metal layer 120, the first lower metal layer 130, and the second upper metal layer 220, the second lower metal layer 230) and the spacer can be greater than the thickness of each of the insulating layers (the first insulating layer 110 and the second insulating layer 210) of the substrate.

[0063] A thermal interface material (TIM) may be disposed between the metal layers and a cooler disposed outside the upper metal layer 120 of the upper substrate 100 and outside the lower metal layer 230 of the lower substrate 200. Preferably, the TIM may be a thermal grease layer.

[0064] Figure 3 TABLE 1 is a table showing the differences in materials, properties, thickness, and CTE of components in an exemplary double-sided cooling type power module according to an exemplary embodiment of the present invention and a conventional power module. Figure 3 As shown, in the present invention, the thermal expansion coefficient can be 13 or greater, and the difference in thermal expansion coefficients of the metal layers (e.g., first upper metal layer 120, first lower metal layer 130, second upper metal layer 220, second lower metal layer 230) can be small, so metal layers of about 0.5 mm or thicker can be used. Therefore, the heat dissipation performance of the entire power module can be improved by increasing the heat dissipation area.

[0065] It can be derived based on the following formula Figure 3 The thermal expansion coefficient of the substrate described in .

[0066] [formula]

[0067] CTE of the substrate surface = CTE of the insulating layer + (CTE of the metal layer – CTE of the insulating layer) × {2 × Young's modulus of the metal layer × thickness of the metal layer / (2 × Young's modulus of the metal layer × thickness of the metal layer + Young's modulus of the insulating layer × thickness of the insulating layer)}

[0068] According to various exemplary embodiments of the present invention, a double-sided cooling type power module having the structure and characteristics of the above-mentioned materials is described below.

[0069] The double-sided cooling type power module according to various exemplary embodiments of the present invention may improve heat discharge performance by using a spacer made of a copper material and may reduce manufacturing costs compared to a related art power module including MMC as a material for the spacer.

[0070] Furthermore, since the insulating layer is disposed in the power module, heat discharge performance is high and the cooler can be easily mounted, so that the convenience of assembly can be improved.

[0071] Furthermore, since a resin-based insulating layer having a low thermal expansion coefficient is used in the upper and lower substrates, a pattern of a copper material of 0.5 mm or thicker can be applied, a heat discharge area can be increased, and heat discharge characteristics can be improved.

[0072] In addition, since the resin-based insulating layer is used, the resin-based insulating layer can absorb vibration generated by pressing when the cooler is coupled to the upper and lower substrates, thereby improving stability.

Claims

1. A double-sided cooling power module, comprising: an upper substrate comprising a first insulating layer, a first upper metal layer and a first lower metal layer, wherein the first upper metal layer is bonded to a top portion of the first insulating layer, and the first lower metal layer is bonded to a bottom portion of the first insulating layer; a lower substrate disposed below the upper substrate and comprising a second insulating layer, a second upper metal layer, and a second lower metal layer, wherein the second upper metal layer is bonded to a top portion of the second insulating layer and the second lower metal layer is bonded to a bottom portion of the second insulating layer; a spacer disposed between the upper substrate and the lower substrate and electrically connecting the upper substrate and the lower substrate; as well as a semiconductor chip arranged between the spacer and the upper substrate or between the spacer and the lower substrate, wherein the insulating layer comprises a material having a thermal expansion coefficient of not less than 0.8 times and not more than 1.2 times the thermal expansion coefficient of the metal layers of the upper substrate and the lower substrate; The thermal expansion coefficient of the insulating layer is 13 or greater, and the thickness of each of the spacer, the first upper metal layer and the first lower metal layer of the upper substrate, and the second upper metal layer and the second lower metal layer of the lower substrate is 0.5 mm or greater; Each of the first insulating layer and the second insulating layer includes a resin material, and the spacer includes a copper material.

2. The double-sided cooling power module according to claim 1, wherein: The spacer, the first upper metal layer and the first lower metal layer of the upper substrate, and the second upper metal layer and the second lower metal layer of the lower substrate are made of the same material.

3. The double-sided cooling power module according to claim 1, wherein: The spacer includes a metal material having a thermal conductivity of 300 W / mK or more.

4. The double-sided cooling power module according to claim 1, wherein: The resin material has a thermal expansion coefficient of 13 or greater and a Young's modulus of 50 GPa or less.

5. The double-sided cooling power module according to claim 1, wherein: The resin material has a thermal conductivity of 15 W / mK or higher and a thickness of 0.2 mm or less.

6. The double-sided cooling power module according to claim 4, wherein: The resin material includes one or more selected from alumina, boron nitride, and aluminum nitride.

7. The double-sided cooling power module according to claim 5, wherein: The content of boron nitride is greater than that of aluminum oxide and aluminum nitride.

8. The double-sided cooling power module according to claim 1, wherein: The thermal expansion coefficients of the surfaces of the upper substrate and the lower substrate are derived from the following formula: [formula] The thermal expansion coefficient of the substrate surface = the thermal expansion coefficient of the insulating layer + (the thermal expansion coefficient of the metal layer - the thermal expansion coefficient of the insulating layer) × {2 × Young's modulus of the metal layer × the thickness of the metal layer / (2 × Young's modulus of the metal layer × the thickness of the metal layer + Young's modulus of the insulating layer × the thickness of the insulating layer)}.

9. The double-sided cooling power module according to claim 1, wherein: The first upper metal layer, the first lower metal layer, the second upper metal layer, the second lower metal layer, and the spacer have the same thickness; A thickness of each of the first upper metal layer, the first lower metal layer, the second upper metal layer, the second lower metal layer, and the spacer is greater than a thickness of the insulating layer.

10. The double-sided cooling power module according to claim 1, wherein: The first cooler is arranged outside the first upper metal layer of the upper substrate, and the second cooler is arranged outside the second lower metal layer of the lower substrate.

11. The double-sided cooling power module according to claim 10, wherein: A thermal interface material is disposed between the first upper metal layer and the first cooler and / or between the second lower metal layer and the second cooler.

12. The double-sided cooling power module according to claim 2, wherein: Each of the spacer, the first upper metal layer and the first lower metal layer of the upper substrate, and the second upper metal layer and the second lower metal layer of the lower substrate includes a copper material. 13 . A vehicle comprising the power module according to claim 1 .

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