Single-tube IGBT parallel packaging method, structure and application

Abstract

The invention relates to a single-tube IGBT parallel packaging method, structure and application, and the method comprises the following steps: a plurality of groups of single-tube IGBT assemblies are placed on a heat dissipation bottom plate, and each group of single-tube IGBT assembly comprises a DBC substrate, a lead frame and a plurality of chips which are sequentially stacked at the upper end of the heat dissipation bottom plate from bottom to top; soldering lugs are placed at contact parts between the heat dissipation bottom plate and the DBC substrate, between the DBC substrate and the lead frame and between the lead frame and the chip; carrying out vacuum reflow soldering, and welding the heat dissipation bottom plate, the DBC substrate, the lead frame and the chip together; the chips are in bonding connection; a shell is arranged on the heat dissipation bottom plate, so that the shell covers the DBC substrate, the lead frame and the plurality of chips; injecting a plastic packaging material into the shell; and curing the plastic packaging material to obtain the single-tube IGBT parallel packaging structure. According to the parallel packaging method for the single-tube IGBTs, the packaging process is not affected by welding high temperature, the yield is high, and the single-tube IGBTs are high in integration level, few in manufacturing steps, low in equipment investment and high in industrial production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging structures, and in particular to a single-tube IGBT parallel packaging method, structure and application. Background Art

[0002] The manufacturing process of a high-current single-tube IGBT parallel driver generally includes the following steps: (1) welding a single-tube IGBT and sealing it in plastic; (2) welding a discrete heat sink, a substrate, and a single-tube IGBT into separate components; (3) connecting multiple components in parallel with the driver board. In this method, a single-tube IGBT requires separate welding equipment, which has high welding costs. In addition, the pin position of the single-tube IGBT must be guaranteed during welding, and positioning tooling must be used. The pin deformation after welding is difficult to control. In addition, since the single-tube IGBT has been plastic-sealed after welding, the temperature of the secondary welding furnace is usually as high as 260 degrees or more. The thermal stress of the plastic seal is different from that of the chip, and there is a risk of delamination, which causes certain damage to the single-tube IGBT and affects the product yield.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0004] In view of the deficiencies in the prior art, the embodiments of the present invention disclose a single-tube IGBT parallel packaging method, structure and application to solve the problems of complex manufacturing process and low yield of single-tube IGBT parallel drivers.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The single-tube IGBT parallel packaging method comprises the following steps: placing a plurality of groups of single-tube IGBT components on a heat dissipation base plate, each group of single-tube IGBT components comprising a DBC substrate, a lead frame and a plurality of chips stacked in sequence from bottom to top on the upper end of the heat dissipation base plate, placing soldering pieces at contact positions between the heat dissipation base plate and the DBC substrate, between the DBC substrate and the lead frame, and between the lead frame and the chip; performing vacuum reflow soldering to weld the heat dissipation base plate, the DBC substrate, the lead frame and the chip together; bonding the chips; forming a shell by applying glue to a dam on the heat dissipation base plate so that the shell surrounds the DBC substrate, the lead frame and the plurality of chips; injecting a plastic encapsulation material into the shell; and curing the plastic encapsulation material to obtain a single-tube IGBT parallel packaging structure.

[0007] A further technical solution is that when the DBC substrate, the lead frame and a plurality of chips are stacked on the heat dissipation base plate from bottom to top, a jig is used to position the heat dissipation base plate, the DBC substrate, the lead frame and the chips.

[0008] A further technical solution is that the side of the lead frame has three pins, and when the shell is formed, the three pins pass through the shell.

[0009] A further technical solution is that the single-tube IGBT components are arranged in parallel along the length direction of the heat dissipation base plate.

[0010] A further technical solution is that a plurality of fins are arranged in parallel in the extension direction of the lower end of the heat dissipation base plate.

[0011] A further technical solution is that during vacuum reflow soldering, the vacuum degree inside the vacuum reflow furnace is below 500ppm and the heating temperature is 260-280°C.

[0012] A further technical solution is that the welding piece adopts an alloy welding piece with a thickness of 0.2 mm.

[0013] A further technical solution is that the plastic encapsulation material is epoxy resin, which is cured by heating in an oven at 120° C. for 1 hour.

[0014] The present invention also discloses a single-tube IGBT parallel packaging structure, comprising: a heat dissipation base plate; a single-tube IGBT component, comprising: a DBC substrate, welded to the upper end of the heat dissipation base plate; a lead frame, electrically connected to the upper end of the DBC substrate; a chip, having a plurality of pieces, electrically connected to the upper end of the lead frame, and bonded to adjacent chips; a shell, which is a hollow structure, fixed to the upper end of the heat dissipation base plate, and covers the single-tube IGBT component; a plastic packaging material, filled in the shell, and plastic-sealing the DBC substrate, lead frame and chip.

[0015] The invention also discloses the application of the single-tube IGBT parallel packaging structure in motor vehicles.

[0016] The beneficial effects of the embodiments of the present invention are as follows:

[0017] (I) The single-tube IGBT parallel packaging method of the present invention is to stack a plurality of groups of single-tube IGBT components in parallel on a heat dissipation base plate, and then weld them together with the heat dissipation base plate before packaging. The packaging process will not be affected by the high temperature of welding, the yield rate is high, the manufacturing steps are few, the equipment investment is small, and the industrial production efficiency is high.

[0018] (ii) Furthermore, multiple groups of single-tube IGBTs are welded and packaged on a whole heat sink. The single-tube IGBT has a high degree of integration. When used in an automobile motor controller, the lower end of the heat sink directly contacts the heat-conducting medium in the water channel, which has good heat dissipation and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of the single-tube IGBT parallel packaging method of the present invention.

[0020] Figure 2 It is a front view structural schematic diagram of the single-tube IGBT parallel packaging structure of the present invention.

[0021] Figure 3 It is a schematic diagram of the top view of the single-tube IGBT parallel packaging structure of the present invention.

[0022] In the figure:

[0023] 1. Heat dissipation base plate; 11. Fins; 2. DBC substrate; 3. Lead frame; 31. Pins; 4. Chip; 41. Bonding wire; 5. Housing; 6. Plastic packaging material; 7. Solder sheet. DETAILED DESCRIPTION

[0024] The specific implementation of the present invention is described below in conjunction with the accompanying drawings.

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the device proposed by the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the accompanying drawings adopt a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the accompanying drawings. It should be noted that the structure, proportion, size, etc. illustrated by the accompanying drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed by the present invention.

[0026] First embodiment:

[0027] This embodiment discloses a method for packaging single-tube IGBTs in parallel.

[0028] The single-tube IGBT parallel packaging method includes the following steps:

[0029] Step S1, placing a plurality of groups of single-tube IGBT components on the heat dissipation base plate 1, each group of single-tube IGBT components includes a DBC substrate 2, a lead frame 3 and a plurality of chips 4 stacked on the upper end of the heat dissipation base plate 1 from bottom to top, and soldering pieces 7 are placed at the contact parts between the heat dissipation base plate 1 and the DBC substrate 2, between the DBC substrate 2 and the lead frame 3, and between the lead frame 3 and the chip 4.

[0030] Specifically, the DBC substrates 2 are arranged in parallel along the length direction of the heat dissipation base plate 1, and the number is set according to demand. The copper layer on the surface of the DBC substrate 2 corresponds to the lower end of the lead frame 3, and the electrode on the lower surface of the chip 4 corresponds to the upper end of the lead frame 3. After welding, the electrode on the lower surface of the chip 4 is electrically connected to the copper layer on the surface of the DBC substrate 2 through the lead frame 3. The welding piece 7 is an alloy welding piece 7, such as a SAC305 welding piece 7 or a SNSB5 welding piece 7, and the thickness is 0.2 mm.

[0031] Preferably, when the DBC substrate 2, the lead frame 3 and several chips 4 are stacked on the heat dissipation base plate 1 from bottom to top, a jig is used to position the heat dissipation base plate 1, the DBC substrate 2, the lead frame 3 and the chips 4 to improve the position accuracy of the single-tube IGBT component and the orientation accuracy of the pin 31.

[0032] Step S2, vacuum reflow soldering is performed to solder the heat dissipation base plate 1, the DBC substrate 2, the lead frame 3 and the chip 4 together.

[0033] Specifically, the stacked single-tube IGBT parallel package structure is placed in a vacuum reflow furnace. During vacuum reflow soldering, the vacuum degree inside the vacuum reflow furnace is below 500 ppm and the heating temperature is 260-280°C.

[0034] Step S3: the chips 4 are bonded to each other.

[0035] Specifically, the chip 4 includes an IGBT chip 4 and an FRD chip 4, the collector metal electrode of the IGBT chip 4 and the cathode electrode of the FRD chip 4 are connected in parallel through the substrate. The emitter metal electrode of the IGBT chip 4, the anode electrode of the FRD chip 4 and one of the pins 31 are connected through a metal bonding wire 41.

[0036] Step S4 , applying glue to the heat dissipation base plate 1 to form a dam shell 5 , so that the shell 5 surrounds the DBC substrate 2 , the lead frame 3 and the plurality of chips 4 .

[0037] Specifically, the outer shell 5 is formed on the heat dissipation base plate 1 by a glue dam. The lead frame 3 has three pins 31 on its side. When the outer shell 5 is formed, the glue penetrates under the pins 31 to wrap the pins 31, ensuring the plastic sealing effect while allowing the three pins 31 to pass through the outer shell 5.

[0038] Step S5 , injecting the plastic packaging material 6 into the housing 5 .

[0039] Specifically, the plastic packaging material 6 is epoxy resin, which has good electrical insulation performance and mechanical strength, and can effectively protect the internal chip 4 and circuits.

[0040] Step S6, curing the plastic packaging material 6 to obtain a single-tube IGBT parallel packaging structure.

[0041] Specifically, the solidification is performed by heating in an oven at 120° C. for 1 hour.

[0042] Furthermore, a plurality of fins 11 are arranged in parallel in the extension direction of the lower end of the heat dissipation bottom plate 1. The fins 11 are located in the water channel below, increasing the contact area between the heat dissipation bottom plate 1 and the heat transfer fluid in the water channel below, thereby improving the heat dissipation efficiency.

[0043] In this embodiment, a plurality of groups of single-tube IGBT components are stacked in parallel on the entire heat dissipation base plate 1, and are welded together with the heat dissipation base plate 1 before packaging. The packaging process will not be affected by the high temperature of welding, the yield rate is high, the manufacturing steps are few, the equipment investment is small, and the industrial production efficiency is high.

[0044] Second embodiment:

[0045] This embodiment discloses a single-tube IGBT parallel packaging structure.

[0046] The single-tube IGBT parallel packaging structure includes a heat dissipation base plate 1, a single-tube IGBT component, a shell 5 and a plastic packaging material 6. The single-tube IGBT component includes a DBC substrate 2, a lead frame 3 and a chip 4. The DBC substrate 2 is welded to the upper end of the heat dissipation base plate 1, and the lead frame 3 is electrically connected to the upper end of the DBC substrate 2. The chip 4 has a plurality of pieces, which are electrically connected to the upper end of the lead frame 3. Adjacent chips 4 are bonded and connected in parallel, and the electrodes of the chip 4 are electrically connected to the pins 31. The shell 5 is a hollow structure, fixed to the upper end of the heat dissipation base plate 1, and covers the single-tube IGBT component. The plastic packaging material 6 is filled in the shell 5 to plastic-encapsulate the DBC substrate 2, the lead frame 3 and the chip 4.

[0047] The single-tube IGBT parallel packaging structure produced in this embodiment can be applied to the motor controller of a motor vehicle, and only the pins 31 of multiple groups of single-tube IGBT components need to be connected to the drive board respectively. When applied to the motor controller of a motor vehicle, the lower end of the heat dissipation base plate 1 is connected to the water tank, and the fins 11 are located in the water channel of the water tank.

[0048] The single-tube IGBT parallel packaging structure produced in this embodiment has a high integration of single-tube IGBTs, and an integral heat dissipation base plate 1 is used at the lower end. When applied to an automobile motor controller, the lower end of the heat dissipation base plate 1 directly contacts the heat-conducting medium in the water channel, has good heat dissipation, and high reliability.

[0049] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0050] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A single-tube IGBT parallel packaging method, characterized in that: The following steps are involved: A plurality of groups of single-tube IGBT components are placed on the heat dissipation base plate, each group of single-tube IGBT components includes a DBC substrate, a lead frame and a plurality of chips stacked on the upper end of the heat dissipation base plate from bottom to top, and solder pieces are placed at the contact parts between the heat dissipation base plate and the DBC substrate, between the DBC substrate and the lead frame, and between the lead frame and the chip; After vacuum reflow soldering, the heat sink, DBC substrate, lead frame and chip are soldered together; Bonding connection between chips; The outer shell is formed by applying glue to the heat dissipation base plate so that the outer shell surrounds the DBC substrate, the lead frame and several chips; and the plastic sealing material is injected into the outer shell; The plastic packaging material is cured to obtain a single-tube IGBT parallel packaging structure.

2. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: When the DBC substrate, the lead frame and a plurality of chips are stacked in sequence from bottom to top on the heat dissipation bottom plate, a jig is used to position the heat dissipation bottom plate, the DBC substrate, the lead frame and the chips.

3. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: The side surface of the lead frame is provided with three pins, and when the shell is formed, the three pins pass through the shell.

4. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: The single-tube IGBT components are arranged in parallel along the length direction of the heat dissipation base plate.

5. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: A plurality of fins are arranged in parallel in the extension direction of the lower end of the heat dissipation bottom plate.

6. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: During vacuum reflow soldering, the vacuum degree inside the vacuum reflow furnace is below 500ppm and the heating temperature is 260-280℃.

7. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: The welding piece is made of alloy welding piece with a thickness of 0.2mm.

8. The single-tube IGBT parallel packaging method according to claim 1, characterized in that: The plastic packaging material is epoxy resin, which is cured by heating in an oven at 120°C for 1 hour.

9. Single-tube IGBT parallel packaging structure, characterized in that: include: Heat dissipation base plate; Single tube IGBT components, including: DBC substrate, welded to the upper end of the heat dissipation base plate; A lead frame electrically connected to the upper end of the DBC substrate; The chip has a plurality of pieces, which are electrically connected to the upper end of the lead frame, and adjacent chips are bonded to each other; The housing is a hollow structure, fixed to the upper end of the heat dissipation base plate, and covers the single-tube IGBT assembly; The plastic packaging material is filled in the shell to plastic-package the DBC substrate, the lead frame and the chip.

10. Application of single-tube IGBT parallel packaging structure in motor vehicles.

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