Electronic device bearing plate for insulated installation of IGBT module chip and IGBT module

Abstract

The invention relates to an electronic device bearing plate for insulated installation of an IGBT module chip and an IGBT module. The electronic device bearing plate is composed of an aluminum plate, wherein the whole surface of the aluminum plate is plated with a SiC ceramic layer. The manufacturing process of the aluminum bearing plate is simple, when an application scene is met, the aluminum bearing plate is used for replacing a ceramic bearing plate in the prior art, the device cost of the IGBT module can be reduced, the machining size of the aluminum bearing plate is basically not limited, a larger design space can be provided for designers, and after the ceramic bearing plate is replaced with the aluminum bearing plate, the manufacturing cost of the IGBT module can be reduced. The weight of the device can be reduced, the structure of the IGBT module is simplified, and the heat dissipation performance of the IGBT module is further improved.

Description

Technical Field

[0001] The invention relates to an electronic device carrier board used for insulating and mounting an IGBT module chip, and an IGBT module using the carrier board. Background Art

[0002] The structure of the traditional IGBT module is as follows Figure 1 As shown in the figure, from top to bottom are (silicon) chip, chip welding material, DBC (Direct Bond Copper) ceramic plate, welding material and substrate, which is the heat conduction block in the figure. Some IGBT modules are also equipped with a heat sink, such as Figure 2 As shown. The ceramic plate is used to achieve the insulation installation of the chip, and the substrate plays the role of heat dissipation, support and connection with the radiator. The above-mentioned ceramic plate used for the insulation installation of the chip requires it to have a high flatness. Due to the limitation of the process level, it is difficult to process, the processing size is limited, and the device cost is high. Summary of the invention

[0003] The present invention aims to provide an electronic device carrier board with a novel structure for insulating and mounting an IGBT module chip. The use of the electronic device carrier board can reduce the device cost of the IGBT module.

[0004] The object of the present invention is achieved through the following technical solution: an electronic device carrier board for insulating and mounting IGBT module chips, characterized in that it is composed of an aluminum plate with a SiC ceramic layer plated on the entire surface.

[0005] Compared with the ceramic carrier plate, the aluminum carrier plate of the present invention has a simpler manufacturing process when achieving the same flatness, can reduce device cost and weight, and is basically not limited in size, thus providing a larger design space.

[0006] Generally speaking, the thicker the SiC ceramic layer is, the better the insulation performance is. Based on cost and application scenario considerations, the recommended thickness range is 1-3um.

[0007] As an optional implementation, the aluminum plate is an aluminum extruded heat sink, the back side of which is a flat surface and the front side is a heat sink with a comb-shaped structure.

[0008] The present invention also provides an IGBT module using the above-mentioned electronic device carrier board, which is composed of a chip, a chip welding material layer, a copper layer and the carrier board stacked in sequence from top to bottom.

[0009] Since the carrier board of the present invention has good insulation and thermal conductivity, it can directly replace the combination of the traditional IGBT module from the ceramic plate to the heat conduction block or further to the heat sink, such as Figure 3 , 4 As shown, not only the structure of the IGBT module is simplified, but also the heat dissipation performance can be further improved.

[0010] Preferably, the copper layer is obtained by first plating a layer of nickel on the carrier plate and then plating a layer of nickel on the carrier plate.

[0011] Beneficial effects:

[0012] The aluminum carrier plate of the present invention has a simple manufacturing process. When the application scenario is met, it can be used to replace the ceramic carrier plate in the prior art to reduce the device cost of the IGBT module. Moreover, the processing size of the aluminum carrier plate of the present invention is basically not restricted, which can provide designers with a larger design space. After replacing the ceramic carrier plate with an aluminum carrier plate, the weight of the device can also be reduced, the structure of the IGBT module can be simplified, and its heat dissipation performance can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 , 2 It is a structural cross-section diagram of a traditional IGBT module;

[0014] Figure 3 It is a structural cross-sectional view of an IGBT module according to a specific embodiment of the present invention;

[0015] Figure 4 is a structural cross-sectional view of a GBT module according to another embodiment of the present invention;

[0016] Figure 5 This is the surface morphology of silicon carbide after etching. DETAILED DESCRIPTION

[0017] Figure 3 This is a cross-sectional view of the structure of the IGBT module of this embodiment. As shown in the figure, excluding conventional packaging structures such as epoxy resin and silicone and some lead structures, it includes the chip, chip welding material layer, copper layer and carrier board from top to bottom. Figure 1 and Figure 3 It can be seen that the present embodiment actually directly replaces the combination of the ceramic plate and the heat-conducting block of the traditional IGBT module with a carrier plate. This is based on the good insulation and thermal conductivity of the carrier plate of the present embodiment, which can be used for both the insulation installation of the chip and the heat dissipation and support. Compared with the prior art, the IGBT module using the carrier plate of the present embodiment not only has a simplified structure and lighter weight, but also has improved heat dissipation performance (a layer of welding material with low thermal conductivity is reduced, the thermal conductivity of the solder layer is 120W / mK, and the thermal conductivity of silicon carbide in the present embodiment can reach 265W / mK).

[0018] The copper layer is recommended to be obtained by first plating a layer of nickel on the carrier plate and then plating it. After masking or etching the circuit, the bottom plate of the chip can be directly welded on the above copper film to form a stacked structure of the IGBT module.

[0019] In this embodiment, the carrier plate is composed of an aluminum plate with a SiC ceramic layer on the entire surface. The full surface here refers to the upper and lower surfaces and four side surfaces, a total of six surfaces, such as a square. For the surface treatment of the electronic device carrier plate, the prior art usually pays more attention to its upper and lower surfaces, and rarely involves the side surfaces. In this embodiment, since it is suitable for high power density devices such as IGBT modules, the treatment of the side surfaces is necessary.

[0020] Figure 4 This shows another implementation method of IGBT module. Figure 2 and Figure 4 It can be seen that this embodiment actually directly replaces the combination of the ceramic plate and the heat sink of the traditional IGBT module with a carrier plate. Figure 3 The biggest difference between the IGBT module of the embodiment is that its carrier plate is composed of an aluminum extruded heat sink with a SiC ceramic layer on the entire surface, and then copper is plated on its flat back side. The copper layer conducts heat and the SiC ceramic layer dissipates heat. The copper layer is masked or etched with a circuit and then welded to the chip to form a stacked structure of the IGBT module. Figure 3 , Figure 4 The IGBT module has better heat dissipation performance. Figure 2 Since the thermal conductivity of the SiC ceramic layer is greater than that of aluminum, it can also improve the heat dissipation of the aluminum extruded heat sink, thereby further improving the heat dissipation characteristics of the IGBT module substrate.

[0021] Based on cost and application scenarios, the recommended thickness range of the SiC ceramic layer on the above-mentioned carrier plate is 1-3um. The insulation resistance range of this SiC ceramic layer is usually 1*10 8 -5*10 9 Ohm, which can meet the application needs of IGBT modules in most scenarios.

[0022] The preferred processing method for the electronic device carrier board of this embodiment is PVD. When obtaining the SiC ceramic layer by PVD, it is easy to first use single crystal silicon for base coating. In terms of coating equipment, it is recommended to select high-power pulse magnetron sputtering coating equipment to obtain sufficient bonding force. At the same time, the configuration of the sputtering source also needs to be considered to ensure the ionization rate. In this embodiment, its power supply configuration is as follows: TruPlasma hipims 4002G220kw, the power supply has a peak voltage of 2000v, a peak current of 1000A, a power of 20KW, a frequency of 10-3000Hz, a pulse width of 1-1000us, and a peak power of 2MW.

[0023] The following are relevant experimental data of the present invention.

[0024] The aluminum plate is plated with a 1um SiC ceramic layer using PVD technology ( Figure 5After showing the surface morphology of silicon carbide after etching), it was tested for room temperature breakdown voltage AC1000V, and the test result was passed. The specific test process is:

[0025] A 50*50*3mm aluminum plate was vacuum-coated with a 1um SiC ceramic layer on the six surfaces in a three-dimensional mode, so that the insulation resistance on the six surfaces reached 1*10 8 Ohms or more. Use a 1000v megohmmeter, connect the positive and negative electrodes to the aluminum plate coated with SiC ceramic layer, with a distance of 10mm between the two electrodes, rotate the megohmmeter manually at a speed of 2 revolutions per second for 120 seconds, and do the same test on the 6 sides of the aluminum plate. The resistance value of the aluminum plate after coating with silicon carbide remains unchanged, and the test passes.

[0026] After silicon carbide treatment, a 200nm nickel layer and a 2um copper layer are plated. The bonding strength between the upper and lower layers is required to reach 4B. After masking or etching the circuit, the chip can be welded.

[0027] Table 1 records the density and thermal conductivity measurement data of the above aluminum plates.

[0028] Table 1

[0029] density <![CDATA[g / cm 3 ]]> 3.2 Thermal conductivity W / mK 265

[0030] Density measurement process: By comparing the weight of the aluminum plate before and after coating, the coating mass Q can be obtained; by the change in the size of the aluminum plate before and after coating, the coating volume V can be obtained. Coating mass Q / coating volume V = coating density. The coating density can approximately reflect the density of the coating. The higher the density, the less porosity and the stronger the breakdown resistance.

[0031] The thermal conductivity measurement adopts the plane heat source method, that is, the temperature change of the upper surface of the aluminum plate after coating is measured by an infrared detector, and the thermal diffusion coefficient is calculated. The thermal conductivity is obtained by combining the apparent density value of the aluminum plate after coating and the specific heat of the coating.

[0032] Replacing the ceramic carrier plate in the IGBT module with the aluminum carrier plate of the present invention can reduce the weight of the device. The aluminum carrier plate is easy to form, which can reduce the cost of the device. When the application scenario is met (in terms of pressure resistance alone, the carrier plate of the present invention is inferior to the ceramic carrier plate), it can replace the ceramic carrier plate in the IGBT module and simplify the structure of the IGBT module.

Claims

1. An electronic device carrier board for insulating and mounting IGBT module chips, characterized in that: It consists of an aluminum plate with a SiC ceramic layer coated on the entire surface.

2. The electronic device carrier board according to claim 1, characterized in that: The aluminum plate is an aluminum extruded radiator, the back side of which is a flat surface and the front side is a comb-shaped radiator.

3. The electronic device carrier board according to claim 1 or 2, characterized in that: The thickness of the SiC ceramic layer is in the range of 1-3 um.

4. An IGBT module using the electronic device carrier board according to claim 1, 2 or 3, characterized in that: It consists of a chip, a chip welding material layer, a copper layer and the carrier board which are stacked in sequence from top to bottom.

5. The IGBT module according to claim 4, characterized in that: The copper layer is obtained by first plating a layer of nickel on the carrier plate and then plating a layer of nickel on the carrier plate.

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