Manufacturing method of power assembly and power assembly packaging structure with high heat dissipation efficiency

Abstract

The application provides a manufacturing method of a power component and a power component packaging structure with high heat dissipation efficiency, and belongs to the technical field of semiconductors. The manufacturing method of the power component comprises the following steps: fixing a chip on a heat-conducting carrier plate, and connecting the chip and pins of the heat-conducting carrier plate through wires; sputtering an insulating film on the side of the heat-conducting carrier plate away from the chip; performing plastic sealing treatment on the heat-conducting carrier plate after sputtering the insulating film; and forming a heat dissipation layer on the surface of the plastic sealing body by film plating. The insulating film formed on the heat-conducting carrier plate by the sputtering method can reduce the manufacturing difficulty of the power component, improve the heat dissipation efficiency of the power component, and make the whole packaging structure smaller in size and thinner in thickness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a manufacturing method of power component and a power component packaging structure with high heat dissipation efficiency. BACKGROUND

[0002] In the field of semiconductor, the packaging technology of power component is very important, which is directly related to the performance, life and reliability of the component. Figure 1 The traditional power component such as TO-247, TO-220 packaging usually uses a ceramic insulating sheet (such as Al2O3, AlN ceramic plate) to be attached between the chip and the metal heat sink, so as to realize electrical isolation and heat conduction. However, this traditional packaging structure has certain defects.

[0003] Firstly, this traditional packaging structure is difficult to balance thinness and insulation. High-power chips will generate a large amount of instantaneous heat when they are dynamically turned on. The high thermal resistance of the traditional packaging structure easily leads to a sharp rise in junction temperature, affecting the life and reliability of the component. Secondly, since the ceramic substrate is not thin film, it cannot be integrated with the existing wafer-level process or vacuum sputtering system, which greatly limits the automation and low-cost high-yield process development of the packaging process. In addition, the thickness of the insulating ceramic is large, the thermal resistance is high, and the packaging needs to be done by mechanical attachment, which cannot be automated, ultimately resulting in a thick, bulky packaging structure, and the manufacturing cost is also high, especially the high thermal conductivity ceramic material is expensive, which further increases the packaging cost.

[0004] Therefore, it is necessary to improve the existing manufacturing method of power component to overcome the defects of the prior art. SUMMARY

[0005] To overcome the problems in the related art, one of the purposes of the present application is to provide a manufacturing method of power component, which uses an insulating thin film formed on a heat-conducting carrier plate by sputtering to reduce the manufacturing difficulty of the power component and improve the heat dissipation efficiency of the power component. And the insulating thin film can make the entire packaging structure smaller and thinner.

[0006] A manufacturing method of power component for manufacturing a power component packaging structure with high heat dissipation efficiency, the manufacturing method of power component comprises:

[0007] Fixing the chip on the heat-conducting carrier plate and connecting the pins of the chip and the heat-conducting carrier plate by wires;

[0008] Sputtering an insulating thin film on the side of the heat-conducting carrier plate away from the chip;

[0009] Plastic packaging treatment is performed on the heat-conducting carrier plate after sputtering the insulating thin film;

[0010] The heat dissipation layer is formed by plating on the surface of the plastic package.

[0011] In the preferred technical solution of the present application, the heat dissipation layer is made of aluminum alloy, and the heat dissipation layer corresponds to the insulating film; and the plating process of the heat dissipation layer and the sputtering process of the insulating film are completed in the same vacuum cavity.

[0012] In the preferred technical solution of the present application, the insulating film is made of aluminum nitride, the thickness of the insulating film is 0.2-5 microns, and the thermal conductivity of the insulating film is not less than 100 W / m·K.

[0013] In the preferred technical solution of the present application, the plastic package comprises glass-filled epoxy resin, and the glass transition temperature is 175-235℃.

[0014] In the preferred technical solution of the present application, the thickness of the plastic package is 3.8-4.5 mm.

[0015] In the preferred technical solution of the present application, the plastic package is provided with a heat transfer member, one end of the heat transfer member is connected to the insulating film, and the opposite end is abutted on the heat dissipation layer.

[0016] In the preferred technical solution of the present application, one side of the heat-conducting carrier plate is provided with a pin, the pin penetrates through the plastic package and is exposed outside the plastic package, and the chip is electrically connected to the pin through gold wires.

[0017] In the preferred technical solution of the present application, the insulating film is sputtered on the side of the heat-conducting carrier plate away from the chip and at least one side surface.

[0018] The second object of the present application is to provide a power component packaging structure with high heat dissipation efficiency, which is made by the above method.

[0019] The present application has the following advantages:

[0020] The application provides a manufacturing method of a power assembly, which comprises the following steps: fixing a chip on a heat-conducting carrier plate, connecting the chip and pins of the heat-conducting carrier plate through wires, sputtering an insulating film on the side of the heat-conducting carrier plate away from the chip, performing plastic sealing treatment on the heat-conducting carrier plate after the sputtering of the insulating film, and forming a heat-dissipating layer on the surface of the plastic sealing body. In the production process, the insulating film is directly sputtered on the back of the heat-conducting carrier plate, and no additional mechanical bonding process is needed, so that the interface thermal resistance between the traditional ceramic sheet and the metal heat-dissipating sheet is avoided, and the volume of the package is reduced. The insulating film is directly sputtered by deposition, and the material utilization rate is high, so that the manufacturing cost can be greatly reduced compared with the structure of the traditional high-thermal-conductivity ceramic sheet. Moreover, the structure of the insulating film can greatly shorten the heat conduction path and reduce the heat loss, which is helpful for optimizing the heat dissipation path, controlling the junction temperature of the chip and prolonging the service life of the assembly.

[0021] The application also provides a power assembly package structure manufactured by the manufacturing method of the power assembly, and the manufacturing process of the structure is simple, the heat dissipation path of the package structure can be optimized, and the working stability of the whole structure is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is an existing power assembly with a ceramic insulating sheet provided in the embodiments of the application;

[0023] Figure 2 is a schematic view of the arrangement of the insulating film on the heat-conducting carrier plate provided in the embodiments of the application;

[0024] Figure 3 is a flowchart of the manufacturing method of the power assembly provided in the embodiments of the application.

[0025] REFERENCE SIGNS:

[0026] 1, plastic sealing body; 2, heat-conducting carrier plate; 21, chip; 22, pin; 3, ceramic insulating sheet; 4, heat-dissipating layer; 5, insulating film. DETAILED DESCRIPTION

[0027] The preferred embodiments of the application will be described in detail below with reference to the accompanying drawings. Although the preferred embodiments of the application are shown in the drawings, it should be understood that the application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the application more thorough and complete, and to fully convey the scope of the application to those skilled in the art.

[0028] In the field of semiconductors, the packaging technology of power assemblies is crucial, which is directly related to the performance, service life and reliability of the assemblies. Referring to Figure 1, traditional power components such as TO-247, TO-220 package, usually with ceramic insulating sheet (such as Al2O3, AlN ceramic plate) paste in the chip and metal heat sink, in order to achieve electrical isolation and heat conduction. However, this traditional packaging structure has certain defects.

[0029] First, this traditional packaging structure is difficult to balance thin and insulation. High power chip in dynamic conduction will produce a large amount of transient heat, the thermal resistance of the traditional packaging structure is too high, easy to lead to the junction temperature soaring, affect the life and reliability of the component. Secondly, because the ceramic base material is not thin film, can not be integrated with the existing wafer level process or vacuum sputtering system, which greatly limits the development of automatic packaging process and low cost high yield process. In addition, the thickness of the insulating ceramic is large, the thermal resistance is high, and the packaging needs to be packaged by mechanical bonding, which cannot be automated, eventually leading to the packaging structure thick, large volume, and high manufacturing cost. Especially the high thermal conductivity of ceramic material is expensive, which further increases the packaging cost.

[0030] Based on this, the application provides a manufacturing method of a power component.

[0031] Embodiment 1

[0032] As Figures 2-3 shown, the manufacturing method of a power component provided by the embodiment,

[0033] for manufacturing a high-efficiency heat dissipation power component packaging structure, the packaging structure comprises:

[0034] The heat-conducting carrier plate 2 is provided with a chip 21; the side of the heat-conducting carrier plate 2 away from the chip 21 is provided with a sputtered insulating film 5; the heat-conducting carrier plate 2 of the application can be made of thick plated nickel copper substrate.

[0035] The plastic package 1 is wrapped around the periphery of the heat-conducting carrier plate 2.

[0036] The manufacturing method of the power component comprises:

[0037] S100, fix the chip on the heat-conducting carrier plate, and connect the pins of the chip and the heat-conducting carrier plate by wires;

[0038] S200, sputter an insulating film on the side of the heat-conducting carrier plate away from the chip; the insulating film is an AlN film.

[0039] S300, plastic encapsulation treatment is performed on the heat-conducting carrier plate after sputtering the insulating film;

[0040] S400, form a heat dissipation layer on the surface of the plastic package.

[0041] Specifically, the heat dissipation layer is made of aluminum alloy, and the heat dissipation layer corresponds to the insulating film; and the plating film forming process of the heat dissipation layer and the sputtering process of the insulating film are completed in the same vacuum cavity. In the same vacuum cavity, after the AlN sputtering is completed, the aluminum alloy plating film is formed, so as to retain the active surface formed in the sputtering process, make the aluminum alloy atoms and the AlN film form a covalent bond, significantly improve the physical adsorption combination of the traditional separate cavity process, and reduce the interface thermal resistance. In actual application, the surface of the plastic package body is treated before the heat dissipation layer is plated, so as to improve the adhesion of the plated layer. For example, the plastic package body is subjected to plasma cleaning and ultraviolet ozone treatment.

[0042] The insulating film 5 is deposited on the side of the heat-conducting carrier plate 2 away from the chip 21 by a radio frequency magnetron sputtering technology to form an aluminum nitride (AlN) film with a thickness of 2 μm, a thermal conductivity of 130 W / m·K, and an insulation withstand voltage of 2.8 kV. After the molding, 1 μm aluminum plating (PVD) is performed on the surface of the plastic package body 1. The measured thermal resistance is reduced from 2.8 K / W to 2.1 K / W, and the overall packaging thickness is reduced from 4.8 mm to 4.2 mm.

[0043] Specifically, one side of the heat-conducting carrier plate 2 is provided with a pin 22, the pin 22 is exposed outside the plastic package body 1, and the chip 21 is electrically connected to the pin 22 through gold wires.

[0044] After the molding, 1 μm aluminum plating (PVD) is performed on the surface of the plastic package body 1. The measured thermal resistance is reduced from 2.8 K / W to 2.1 K / W, and the overall packaging thickness is reduced from 4.8 mm to 4.2 mm.

[0045] More preferably, the outer wall of the plastic package body 1 is provided with a heat dissipation layer 4, and the heat dissipation layer 4 corresponds to the insulating film 5. In the position of the outer wall of the plastic package body 1 corresponding to the insulating film 5, 1 μm thick aluminum metal plating film (thermal conductivity 237 W / m·K) is formed by physical vapor deposition (PVD), and the area matches the insulating film 5.

[0046] Specifically, the insulating film 5 of the present application is an AlN film, which is directly covered on the back of the heat-conducting carrier plate 2 to quickly conduct the heat conducted by the chip 21 through the substrate and reduce the thermal resistance. Compared with the traditional ceramic insulating sheet 3 (thickness > 0.5 mm, high thermal resistance), the 2 μm thin film structure greatly shortens the heat conduction distance and reduces the heat loss. In a specific embodiment, the thickness of the insulating film 5 is 0.2 μm to 5 μm, and the thermal conductivity of the insulating film 5 is not less than 100 W / m·K.

[0047] The aluminum metal heat dissipation layer 4 of the outer wall of the plastic package body 1 corresponds to the position of the insulating film 5, forming a heat conduction chain of “insulating film 5-plastic package body 1-heat dissipation layer 4”. The high thermal conductivity of aluminum metal accelerates the heat diffusion to the environment, greatly reduces the measured thermal resistance, and improves the chip 21 junction temperature control capability.

[0048] And 2 μm aluminum nitride film can achieve 2.8 kV voltage resistance, better than the same thickness performance of the traditional ceramic sheet, and the thin film design avoids the thickness limit of the traditional ceramic sheet, so that the overall thickness of the package is reduced to 4.2 mm, meeting the thinness requirement. The insulating film 5 is directly sputtered on the substrate, without additional mechanical bonding process, reducing the package size; the heat dissipation layer 4 is integrated on the surface of the plastic package 1 by PVD, without increasing additional space, realizing the integration of the thin film of the "insulation-heat dissipation" function.

[0049] Further, the plastic package 1 comprises a glass-filled epoxy resin, wherein the glass transition temperature is between 175℃ and 235℃.

[0050] The plastic package 1 of the present application uses a glass-filled epoxy resin with a glass transition temperature (Tg) of 175℃ to 235℃, so that the plastic package 1 material is still in a glass state when the chip 21 is working, maintaining structural rigidity, avoiding material softening or deformation due to temperature close to Tg (traditional low Tg material is prone to plastic package 1 collapse at high temperature, affecting the stability of the internal structure).

[0051] Moreover, the coefficient of thermal expansion (CTE) of the glass-filled epoxy resin can be adjusted by the proportion of glass filler, which can better match the CTE of the AlN thin film (CTE≈4.1×10 -6 / ℃), the copper-based carrier board (CTE≈17×10 -6 / ℃). When Tg is higher than the working temperature, the material is in a low expansion state in the thermal cycle, reducing the delamination of the thin film-substrate interface or the cracking of the plastic package 1 caused by CTE mismatch.

[0052] Further, the thickness of the plastic package 1 is 3.8mm-4.5mm. The thickness of the plastic package 1 is controlled to be 3.8mm-4.5mm, which can make the packaging structure thinner.

[0053] Embodiment 3

[0054] The plastic package 1 is provided with a heat transfer member, one end of the heat transfer member is connected with the insulating film 5, and the opposite end abuts on the heat dissipation layer 4. The insulating film 5 is made of aluminum nitride, and the insulating film 5 is sputtered on the side of the heat-conducting carrier board 2 away from the chip 21 and at least one side.

[0055] The heat transfer member of the present application can be a heat transfer member provided in the plastic package 1, mainly including a heat dissipation carrier, a heat dissipation block, a heat-conducting metal sheet, an insulating heat-conducting glue, etc.

[0056] For example, in a specific embodiment, the heat transfer member is a 0.2 mm thick copper sheet (thermal conductivity 401 W / m·K), with dimensions of 12 mm x 4 mm, one end of the heat transfer member is fixed by silver paste welding with the AlN film on the side surface of the heat conducting carrier 2, and the other end extends to the outer wall of the plastic package 1 and is in contact with the aluminum metal heat dissipation layer 4.

[0057] The side surface AlN film of the packaging structure forms a "side surface insulation-metal heat conduction" channel with the copper heat transfer member, directly conducting heat to the heat dissipation layer 4 on the outer wall of the plastic package 1, effectively reducing the measured thermal resistance, and solving the problem of insufficient side surface heat dissipation in traditional packaging. The copper heat transfer member (thermal conductivity 401 W / m·K) as a solid thermal bridge directly connects the side surface AlN film and the external heat dissipation layer 4, reducing the interfacial thermal resistance in heat conduction (traditional plastic package 1 relies on epoxy resin for heat conduction, with a thermal conductivity of only 1.5-2.0 W / m·K), forming a high-efficiency heat conduction chain of "chip 21-substrate-AlN-heat transfer member-heat dissipation layer 4".

[0058] Example 4

[0059] In this embodiment, a 1200V IGBT chip 21 is used as a high-voltage application test object, a 3μm AlN insulating film is formed on the bare chip by RF sputtering, and then a copper-based wire is coated and molded. The outside of the package is treated with a 1μm aluminum plating film and a surface laser etching microstructure is added to improve the heat dissipation convection efficiency. According to the actual measurement, the thermal resistance of the packaging structure of this embodiment is reduced from 3.5K / W to 2.6K / W, the withstand voltage breaks through 3.2kV, and the overall packaging thickness is controlled within 4.5mm.

[0060] The foregoing is a summary and thus contains only the most basic embodiment. The application can be practiced with the specific embodiments and options described herein, and it will be apparent that modifications and variations are possible without departing the application, including uses of the application in scenarios different than those described above. Other objects, features and aspects of the present application are disclosed in or are apparent from the following detailed description, which, together with the figures, represents the best now known embodiment. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent example functional relationships and / or physical or logical couplings between the various entities depicted in the figures. It should be noted that many alternative or equivalent implementations can be practiced, and that the following description is not intended to limit the application insofar as the application is described in the claims.

[0061] For purposes of the US, this laid-open application claims priority to U.S. Provisional Patent Application No. 62 / 1 12, 1 1 1, filed on February 1 1, 2015, the content of which is relied upon and incorporated herein by reference in its entirety.

[0062] In addition, it should be noted that the use of "first", "second", and the like words to define parts is merely for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, and therefore cannot be understood as limiting the scope of protection of the present application. The above is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A method of manufacturing a power assembly, characterized by, The application discloses a power component package structure with high heat dissipation efficiency and a manufacturing method thereof. The chip is fixed on the heat-conducting carrier plate, and the chip and the pins of the heat-conducting carrier plate are connected through wires; An insulating film is sputtered on the side of the heat-conducting carrier plate away from the chip; The heat-conducting carrier plate after the sputtering of the insulating film is subjected to plastic encapsulation treatment; A heat dissipation layer is formed on the surface of the plastic encapsulation body through film plating; The heat-conducting carrier plate is provided with a heat-conducting piece, one end of the heat-conducting piece is connected with the insulating film, and the opposite end is supported on the heat dissipation layer; The heat-conducting piece is a heat dissipation carrier plate, a heat dissipation block, a heat-conducting metal sheet or an insulating heat-conducting glue provided in the plastic encapsulation body.

2. The manufacturing method of the power component according to claim 1, wherein: The heat dissipation layer is made of an aluminum alloy, the heat dissipation layer corresponds to the insulating film, and the film plating process of the heat dissipation layer and the sputtering process of the insulating film are completed in the same vacuum cavity.

3. The manufacturing method of the power component according to claim 1, wherein: The insulating film is made of aluminum nitride, the thickness of the insulating film is 0.2-5 μm, and the thermal conductivity of the insulating film is not less than 100 W / m·K.

4. The manufacturing method of the power component according to any one of claims 1-3, wherein: The plastic encapsulation body comprises a glass-filled epoxy resin, and the glass transition temperature of the glass-filled epoxy resin is 175-235 °C.

5. The manufacturing method of the power component according to claim 4, wherein: The thickness of the plastic encapsulation body is 3.8-4.5 mm.

6. The manufacturing method of the power component according to claim 1, wherein: The heat-conducting carrier plate is provided with pins on one side, the pins are exposed outside the plastic encapsulation body, and the chip is electrically connected with the pins through gold wires.

7. The manufacturing method of the power component according to claim 1, wherein: The insulating film is sputtered on the side of the heat-conducting carrier plate away from the chip and at least one side surface.

8. A power module package structure with high heat dissipation, characterized in that, The power component is manufactured by using the manufacturing method of the power component according to any one of claims 1-7.

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