Package structure and semiconductor device

Abstract

The present application relates to a kind of packaging structure and semiconductor device, the packaging structure includes: a kind of packaging structure, including: lead frame, with opposite first face and second face;Metal layer, relative to the first face is arranged;Metal column, between the first face and the metal layer is provided;Wherein, the metal column supports the metal layer and is used to conduct the heat generated by the die to the metal layer, the first face includes die area, and the die area is used to set die.The present application is by adding metal column in the first face of lead frame in several positions (especially near heat source), to effectively conduct heat from lead frame to metal layer, realize the double-side heat dissipation of the second face of lead frame and the top surface of metal layer.On the other hand, the present application uses mature packaging material, and can be realized by common packaging process, while realizing double-side effective heat dissipation, also has cost advantage, and can realize electrical insulation.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and in particular to a semiconductor device packaging structure based on a lead frame, and also to a semiconductor device based on the packaging structure. Background Technology

[0002] For lead-frame based packaging structures, some applications require good heat dissipation and cost advantages. Summary of the Invention

[0003] Therefore, it is necessary to provide a simple double-sided heat dissipation packaging structure based on a lead frame.

[0004] A packaging structure includes: a lead frame having a first side and a second side opposite to each other; a metal layer disposed opposite to the first side; and a metal pillar disposed between the first side and the metal layer; wherein the metal pillar supports the metal layer and is used to conduct heat generated by the die to the metal layer, and the first side includes a die region for disposing of the die.

[0005] In the aforementioned packaging structure, the second side of the lead frame already achieves single-sided heat dissipation. By adding metal pillars at several locations on the first side of the lead frame and / or directly on the die, heat is effectively conducted from the lead frame to the metal layer, achieving double-sided heat dissipation. Furthermore, the aforementioned packaging structure uses mature packaging materials and can be implemented using common packaging processes. Compared to exemplary solutions employing special electrical insulating films, the aforementioned packaging structure achieves effective double-sided heat dissipation while also offering a cost advantage.

[0006] In one embodiment, each of the metal pillars is connected to the lead frame and the metal layer by solder.

[0007] In one embodiment, each of the metal pillars is positioned close to the core region.

[0008] In one embodiment, the plurality of metal pillars includes a first metal pillar disposed on the first surface and a second metal pillar disposed on the second surface, and the metal layer includes a first metal plate connected to each of the first metal pillars and a second metal plate connected to each of the second metal pillars.

[0009] In one embodiment, at least one end of each of the first metal pillars is provided with an insulating thermally conductive medium, and at least one end of each of the second metal pillars is provided with the insulating thermally conductive medium.

[0010] In one embodiment, the insulating thermally conductive medium comprises a copper-clad ceramic substrate.

[0011] In one embodiment, each of the first metal pillars is connected to the first metal layer by solder, and the insulating thermally conductive medium is provided between each of the first metal pillars and the lead frame; each of the second metal pillars is connected to the second metal layer by solder, and the insulating thermally conductive medium is provided between each of the second metal pillars and the lead frame.

[0012] It is also necessary to provide a semiconductor device.

[0013] A semiconductor device includes a die and a package structure, the package structure including: a lead frame having opposing first and second surfaces; a plurality of metal pillars disposed on the first surface; and a metal layer disposed on each of the metal pillars; wherein each of the metal pillars supports the metal layer and is used to conduct heat from the lead frame to the metal layer, and the first surface includes a die region for disposing of the die.

[0014] In one embodiment, each of the metal pillars is connected to the lead frame and the metal layer by solder.

[0015] In one embodiment, each of the metal pillars is positioned close to the core region.

[0016] In one embodiment, the plurality of metal pillars includes a first metal pillar disposed on the first surface and a second metal pillar disposed on the second surface, and the metal layer includes a first metal plate connected to each of the first metal pillars and a second metal plate connected to each of the second metal pillars.

[0017] In one embodiment, at least one end of each of the first metal pillars is provided with an insulating thermally conductive medium, and at least one end of each of the second metal pillars is provided with the insulating thermally conductive medium.

[0018] In one embodiment, the insulating thermally conductive medium comprises a copper-clad ceramic substrate.

[0019] In one embodiment, each of the first metal pillars is connected to the first metal layer by solder, and the insulating thermally conductive medium is provided between each of the first metal pillars and the lead frame; each of the second metal pillars is connected to the second metal layer by solder, and the insulating thermally conductive medium is provided between each of the second metal pillars and the lead frame.

[0020] In one embodiment, the die is connected to the first surface by solder.

[0021] In one embodiment, the plurality of metal pillars are arranged around the core. Attached Figure Description

[0022] To better describe and illustrate embodiments and / or examples of the inventions disclosed herein, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the disclosed inventions, the currently described embodiments and / or examples, or the best mode of these inventions as currently understood.

[0023] Figure 1 This is a schematic diagram of the packaging structure in one embodiment;

[0024] Figure 2 This is a schematic diagram of the packaging structure in another embodiment;

[0025] Figure 3 This is a schematic diagram of the encapsulation structure in another embodiment. Detailed Implementation

[0026] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0029] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0030] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0031] Embodiments of the invention are described herein with reference to cross-sectional views that serve as schematic diagrams of ideal embodiments (and intermediate structures). Thus, variations in the shape shown can be anticipated due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing processes. For example, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes are not intended to show the actual shapes of the regions of the device and are not intended to limit the scope of the invention.

[0032] In exemplary lead-frame packages, the leadframe is exposed for better heat dissipation without considering electrical insulation. In general, lead-frame packages have two structural forms: (1) single-sided heat dissipation – connected by wire bonding or copper clip bridging; (2) double-sided heat dissipation – connected by copper clip bridging. While both structures achieve effective heat dissipation on one or both sides of the package, the leadframe lacks electrical isolation, thus requiring solutions for electrical insulation during use.

[0033] Considering electrical insulation, there are two exemplary methods for leadframe packaging: (1) encapsulating the leadframe with a molding compound to achieve electrical insulation. However, this method is not suitable for medium and high power module products due to its high thermal resistance; (2) using a special electrically insulating film with excellent thermal conductivity to achieve electrical insulation. Although its thermal resistance is significantly reduced compared to method (1), allowing leadframe packaging to be applied to medium power module products, the cost is high, and such special electrically insulating films with excellent thermal conductivity are often regarded as core technologies by R&D manufacturers and used exclusively.

[0034] For power module packaging, due to the aforementioned limitations of leadframe packaging, although it is low-cost and has mature technology, it is currently generally limited to low-power power module products. Medium and high-power modules require metal-based PCB (Isolated Metal Substrate) or ceramic substrate packaging.

[0035] The purpose of this invention is to solve the problem of effective double-sided cooling in leadframe packaging, while also proposing a cost-effective solution. This would enable leadframe packaging to become a competitive packaging solution for medium- and high-power module products.

[0036] This application first provides a leadframe-based double-sided cooling package structure for semiconductor devices that does not consider electrical insulation. Figure 1 This is a schematic diagram of the encapsulation structure in one embodiment. In this embodiment, the encapsulation structure includes a lead frame 110 and multiple metal pillars 120. Figure 1 The image shows two metal pillars 120 and a metal layer 130.

[0037] The lead frame 110 has a first surface 111 and a second surface 113. Metal posts 120 are disposed on the lead frame 110, with the bottom of each metal post 120 fixed to the first surface 111 of the lead frame 110. A metal layer 130 is disposed on each metal post 120, and the metal posts 120 support the metal layer 130. The metal layer 130 may be a metal plate. Figure 1The location of the die within the package structure is also shown. Specifically, the die 20 is positioned in the die region of the first surface 111 of the lead frame 110. Figure 1 (Not marked in the text)

[0038] exist Figure 1 In the embodiment shown, the die 20 is connected to the first surface 111 by solder 112. The heat generated by the die 20 during operation is conducted to the lead frame 110, and each metal post 120 can conduct the heat of the lead frame 110 to the metal layer 130, thereby achieving double-sided heat dissipation.

[0039] In the aforementioned packaging structure, the second surface 113 of the lead frame 110 already achieves single-sided heat dissipation (without electrical insulation). By adding metal pillars 120 at several locations on the first surface 111 of the lead frame 110 (especially near heat sources), heat is effectively conducted from the lead frame 110 to the metal layer 130, achieving double-sided heat dissipation. Furthermore, this packaging structure uses mature packaging materials and can be implemented using common packaging processes. Compared to exemplary solutions employing special electrical insulating films, this packaging structure achieves effective double-sided heat dissipation while also offering cost advantages.

[0040] exist Figure 1 In the embodiment shown, the bottom of each metal pillar 130 is connected to the lead frame 110 by solder 122, and the top is connected to the metal layer 130 by solder 122.

[0041] In one embodiment of this application, a heat sink may also be installed on the second surface 113 of the lead frame 110 and / or the top surface of the metal layer 130 to aid in heat dissipation. The heat sink may include heat dissipation fins, a thermoelectric cooler, thermally conductive silicone, etc.

[0042] In one embodiment of this application, each metal pillar 120 is disposed close to the die 20. Further, each metal pillar 120 is disposed around the die 20. In one embodiment of this application, one end of a portion of the metal pillars 120 is connected to the metal layer 130, and the other end is connected to the die 20. Directly disposing the metal pillars 120 on the die 20 can further improve thermal conductivity. However, for some die structures, it is difficult to directly dispose of the metal pillars 120 on the die. In one embodiment of this application, the metal pillars 120 directly disposed on the die may not be connected to the metal layer 130.

[0043] The packaging structure described in any of the above embodiments can be applied to discrete components or to module products (such as power modules), enabling leadframe packaging to be a competitive packaging solution for medium and high power module products.

[0044] Figure 2This is a schematic diagram of the packaging structure in another embodiment. In this embodiment, the packaging structure includes a lead frame 210, multiple first metal pillars 222, and multiple second metal pillars 224. Figure 2 The diagram shows two first metal pillars 222 and two second metal pillars 224, a first metal layer 232, and a second metal layer 234. The lead frame 210 has opposing first surfaces 211 and second surfaces 213. Each first metal pillar 222 is disposed on the first surface 211, and each second metal pillar 224 is disposed on the second surface 213. The bottom of each first metal pillar 222 is fixed to the first surface 211 of the lead frame 210, and the top of each second metal pillar 224 is fixed to the second surface 213 of the lead frame 210. A first metal layer 232 is disposed on each first metal pillar 222, supporting the first metal layer 232. A second metal layer 234 is disposed at the bottom of each second metal pillar 224, and the second metal layer 234 is connected to the lead frame 210 via the second metal pillars 224. The first metal layer 232 and the second metal layer 234 can be metal plates. Figure 2 The location of the die within the package structure is also shown. Specifically, the die 20 is positioned in the die region of the first surface 211 of the lead frame 210. Figure 2 (Not marked in the text)

[0045] The aforementioned encapsulation structure effectively conducts heat from the lead frame 210 to the first metal layer 232 and the second metal layer 234 by adding first metal pillars 222 at several locations on the first surface 211 of the lead frame 210 (especially near heat sources) and second metal pillars 224 at several locations on the second surface 213 of the lead frame 210 (especially near heat sources), thereby achieving double-sided heat dissipation. Furthermore, this encapsulation structure uses mature encapsulation materials and can be implemented using common encapsulation processes. Compared to exemplary solutions employing special electrical insulating films, this encapsulation structure achieves effective double-sided heat dissipation while also offering cost advantages.

[0046] exist Figure 2 In the embodiment shown, the bottom of the first metal pillar 222 is connected to the lead frame 210 by solder 221, and the top is connected to the first metal layer 232 by solder 221; the top of the second metal pillar 224 is connected to the lead frame 210 by solder 221, and the bottom is connected to the second metal layer 234 by solder 221.

[0047] In one embodiment of this application, a heat sink may also be installed on the top surface of the first metal layer 232 and / or the bottom surface of the second metal layer 234 to aid in heat dissipation. The heat sink may include heat dissipation fins, a thermoelectric cooling chip, thermally conductive silicone, etc.

[0048] The packaging structure described in any of the above embodiments can be applied to discrete components or to module products (such as power modules), enabling leadframe packaging to be a competitive packaging solution for medium and high power module products.

[0049] Figure 3 This is a schematic diagram of the encapsulation structure in another embodiment, applicable to products requiring electrical insulation. In this embodiment, the encapsulation structure includes a lead frame 210, multiple first metal pillars 222, and multiple second metal pillars 224. Figure 3 The diagram shows two first metal pillars 222 and two second metal pillars 224, a first metal layer 232, and a second metal layer 234. The lead frame 210 has opposing first surfaces 211 and second surfaces 213. Each first metal pillar 222 is disposed on the first surface 211, and each second metal pillar 224 is disposed on the second surface 213. The bottom of each first metal pillar 222 is fixed to the first surface 211 of the lead frame 210, and the top of each second metal pillar 224 is fixed to the second surface 213 of the lead frame 210. A first metal layer 232 is disposed on each first metal pillar 222, supporting the first metal layer 232. A second metal layer 234 is disposed at the bottom of each second metal pillar 224, and the second metal layer 234 is connected to the lead frame 210 via the second metal pillars 224. The first metal layer 232 and the second metal layer 234 can be metal plates. Figure 3 The location of the die within the package structure is also shown. Specifically, the die 20 is positioned in the die region of the first surface 211 of the lead frame 210. Figure 3 (Not marked in the text)

[0050] In one embodiment of this application, at least one end of each first metal pillar 222 is provided with an insulating thermally conductive medium (i.e., an insulating thermally conductive medium is provided between the bottom of the first metal pillar 222 and the lead frame 210, and / or an insulating thermally conductive medium is provided between the top of the first metal pillar 222 and the first metal layer 232); at least one end of each second metal pillar 242 is provided with an insulating thermally conductive medium (i.e., an insulating thermally conductive medium is provided between the top of the second metal pillar 224 and the lead frame 210, and / or an insulating thermally conductive medium is provided between the bottom of the second metal pillar 224 and the second metal layer 234).

[0051] exist Figure 3 In the illustrated embodiment, the insulating and thermally conductive medium is a direct copper-clad ceramic substrate (DCB) 242. See also... Figure 3The first metal pillar 222 is connected to the first metal layer by solder 221, and a copper-clad ceramic substrate 242 is provided between the first metal pillar 222 and the lead frame 210; the second metal pillar 224 is connected to the second metal layer 234 by solder 221, and a copper-clad ceramic substrate 242 is provided between the second metal pillar 224 and the lead frame 210.

[0052] exist Figure 3 In the illustrated embodiment, the die 20 is connected to the first surface 211 via solder 212, and the heat generated by the die 20 during operation is conducted to the lead frame 110. Insulating thermally conductive media are provided at at least one end of each of the first metal pillars 222 and at least one end of each of the second metal pillars 224, providing insulation and achieving electrical insulation between the first metal layer 232 and the second metal layer 234 and the die 20 on the lead frame 210.

[0053] Copper-clad ceramic substrates offer high thermal conductivity, but custom-designed copper-clad ceramic substrates are relatively expensive. Figure 3 In the packaging structure shown, the copper-clad ceramic substrate is disposed at one end of the first metal pillar 222 and the second metal pillar 224, thus allowing the use of common copper-clad ceramic substrate components. This utilizes the electrical isolation and high thermal conductivity of the copper-clad ceramic substrate while significantly reducing its cost. Although Figure 3 In the illustrated embodiment, the heat dissipation effect of the partially placed copper-clad ceramic substrate structure is not as good as that of the fully copper-clad ceramic substrate design, but the most effective heat dissipation area is the area below and near the die. Figure 3 The illustrated embodiment places copper-clad ceramic substrate structures in these most effective heat dissipation areas, and the above-described packaging structure can provide heat dissipation from both sides, which is an advantage over traditional copper-clad ceramic substrate structures.

[0054] The aforementioned encapsulation structure effectively conducts heat from the lead frame 210 to the first metal layer 232 and the second metal layer 234 by adding first metal pillars 222 at several locations on the first surface 211 of the lead frame 210 (especially near heat sources) and second metal pillars 224 at several locations on the second surface 213 of the lead frame 210 (especially near heat sources), thereby achieving double-sided heat dissipation. Furthermore, this encapsulation structure uses mature encapsulation materials and can be implemented using common encapsulation processes. Compared to exemplary solutions employing special electrical insulating films, this encapsulation structure achieves effective double-sided heat dissipation while also offering cost advantages.

[0055] In one embodiment of this application, one end of a portion of the first metal pillars 222 is connected to the first metal layer 232, and the other end is connected to the die 20. The first metal pillars 222 are directly disposed on the die 20, which can further improve thermal conductivity. However, for some die structures, it is difficult to directly dispose of the first metal pillars 222 on the die. In one embodiment of this application, the first metal pillars 222 directly disposed on the die may not be connected to the first metal layer 232.

[0056] In one embodiment of this application, a heat sink may also be installed on the top surface of the first metal layer 232 and / or the bottom surface of the second metal layer 234 to aid in heat dissipation. The heat sink may include heat dissipation fins, a thermoelectric cooling chip, thermally conductive silicone, etc.

[0057] The packaging structure described in any of the above embodiments can be applied to discrete components or to module products (such as power modules), enabling leadframe packaging to be a competitive packaging solution for medium and high power module products.

[0058] This application provides a semiconductor device packaged using the packaging structure described in any of the foregoing embodiments, which includes a die and the packaging structure described in any of the foregoing embodiments.

[0059] In one embodiment of this application, the packaging structure includes: a lead frame having a first side and a second side opposite to each other; a plurality of metal pillars disposed on the lead frame; and a metal layer disposed on each of the metal pillars; wherein each of the metal pillars supports the metal layer and is used to conduct heat from the lead frame to the metal layer, and the first side includes a die region for disposing of a die.

[0060] In one embodiment of this application, each of the metal pillars is connected to the lead frame and the metal layer by solder.

[0061] In one embodiment of this application, each of the metal pillars is disposed close to the core region.

[0062] In one embodiment of this application, the plurality of metal pillars includes a first metal pillar disposed on the first surface and a second metal pillar disposed on the second surface, and the metal layer includes a first metal plate connected to each of the first metal pillars and a second metal plate connected to each of the second metal pillars.

[0063] In one embodiment of this application, at least one end of each of the first metal pillars is provided with an insulating thermally conductive medium, and at least one end of each of the second metal pillars is provided with the insulating thermally conductive medium.

[0064] In one embodiment of this application, the insulating thermally conductive medium includes a copper-clad ceramic substrate.

[0065] In one embodiment of this application, each of the first metal pillars is connected to the first metal layer by solder, and the insulating thermally conductive medium is provided between each of the first metal pillars and the lead frame; each of the second metal pillars is connected to the second metal layer by solder, and the insulating thermally conductive medium is provided between each of the second metal pillars and the lead frame.

[0066] In one embodiment of this application, the die is connected to the first surface by solder.

[0067] In one embodiment of this application, the plurality of metal pillars are disposed around the core.

[0068] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A packaging structure, characterized in that, include: A lead frame having opposing first and second faces; The metal layer includes a first metal layer disposed opposite to the first surface; A metal pillar, including a first metal pillar disposed between the first surface and the metal layer; The metal pillar supports the metal layer and conducts heat generated by the die to the metal layer. The first surface includes a die area for housing the die. The metal pillar also includes a second metal pillar disposed on the second surface. The first metal layer is connected to the first metal pillar, and the metal layer also includes a second metal layer. The second metal layer is connected to the lead frame via the second metal pillar. At least one end of the first metal pillar is provided with an insulating thermally conductive medium, and at least one end of the second metal pillar is provided with the insulating thermally conductive medium. The insulating thermally conductive medium is disposed between the bottom of the first metal pillar and the lead frame, between the top of the first metal pillar and the first metal layer, between the top of the second metal pillar and the lead frame, and between the bottom of the second metal pillar and the second metal layer.

2. The packaging structure according to claim 1, characterized in that, The metal pillars are connected to the lead frame and the metal layer by solder.

3. The packaging structure according to claim 1, characterized in that, The metal pillar is positioned close to the core area.

4. The packaging structure according to claim 1, characterized in that, The insulating and thermally conductive medium includes a copper-clad ceramic substrate.

5. The packaging structure according to claim 1 or 4, characterized in that, The first metal pillar is connected to the first metal layer by solder, and the insulating thermally conductive medium is provided between the first metal pillar and the lead frame; the second metal pillar is connected to the second metal layer by solder, and the insulating thermally conductive medium is provided between the second metal pillar and the lead frame.

6. A semiconductor device comprising a die, characterized in that, It also includes the packaging structure as described in any one of claims 1-5.

7. The semiconductor device according to claim 6, characterized in that, The die is connected to the first surface by solder.

8. The semiconductor device according to claim 6, characterized in that, The metal pillars are arranged around the core.

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