Double-sided heat dissipation common drain module packaging structure

Abstract

The invention discloses a double-sided heat dissipation common drain module packaging structure, and belongs to the technical field of power semiconductor device packaging. The module comprises a common drain electrode upper copper layer, two drain electrode copper terminals, two power chips, two source electrode copper blocks, two L-shaped source electrode lower copper layers, two driving grid electrode copper terminals, two driving source electrode copper terminals and a bonding wire. Drain electrodes of the two power chips are welded on the common drain electrode upper copper layer, and source electrodes of the two power chips are respectively welded with the L-shaped source electrode lower copper layer through source electrode copper blocks. And the bonding wire is connected with the grid electrode and the source electrode of the chip and the driving copper terminal to realize Kelvin connection. Thermal resistance is reduced through a double-sided heat dissipation structure, parasitic inductance is reduced through a three-dimensional commutation loop, power density and reliability are improved, and the common drain geminate transistor is suitable for common drain geminate transistor application in a battery management system.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor device packaging technology, and in particular to a common-drain module packaging structure with double-sided heat dissipation. Background Technology

[0002] As the core of power conversion, the packaging technology of power semiconductor devices is crucial. Traditional packages such as TO-247 and DDPAK generally use wire bonding for electrical connection and single-sided heat dissipation, which has problems such as large parasitic inductance, high thermal resistance, and limited reliability. The parasitic inductance introduced by wire bonding can lead to severe voltage overshoot and electromagnetic interference at high switching frequencies, while the single-sided heat dissipation structure limits the improvement of power density.

[0003] The common-drain pair topology is widely used in battery management systems (BMS) for battery monitoring and protection. Currently, this function is often implemented using two discrete TO-247 packaged devices on a PCB board. However, this approach has drawbacks such as scattered layout, large parasitic inductance (including the device's own inductance and PCB wiring inductance), large size, and low heat dissipation efficiency.

[0004] To address the above problems, there is an urgent need for a solution that can comprehensively optimize parasitic parameters and enhance heat dissipation. Summary of the Invention

[0005] The purpose of this invention is to provide a common-drain module packaging structure with double-sided heat dissipation to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides a common-drain module packaging structure with double-sided heat dissipation, including a common-drain upper copper layer, with drain copper terminals provided at both ends of the common-drain upper copper layer, the drain copper terminals and the common-drain upper copper layer being the same copper layer; two power chips are fixedly connected to the bottom end of the common-drain upper copper layer, each of the two power chips having a driving gate copper terminal and a driving source copper terminal connected to it; a source copper block is fixedly connected to the bottom end of each of the two power chips, and an L-shaped source lower copper layer is fixedly connected to the bottom end of the source copper block; heat dissipation structures are connected to the top end of the common-drain upper copper layer and the bottom end of the L-shaped source lower copper layer.

[0007] Preferably, the heat dissipation structure at the top of the copper layer on the common drain electrode is a heat sink, and the heat dissipation structure at the bottom of the copper layer under the L-shaped source electrode is a PCB board.

[0008] Preferably, the two power chips are a first power chip and a second power chip, and the common-drain copper layer, the source copper block and L-shaped source lower copper layer corresponding to the first power chip, and the source copper block and L-shaped source lower copper layer corresponding to the second power chip together form a commutation circuit.

[0009] Preferably, the common-drain upper copper layer and the power chip, the power chip and the source copper block, and the source copper block and the L-shaped source lower copper layer are all soldered together.

[0010] Preferably, the driving gate copper terminal is connected to the gate electrode of the power chip via a bonding wire, and the driving source copper terminal is connected to the source electrode of the power chip via a bonding wire, forming a Kelvin connection for reducing common source inductance.

[0011] Preferably, it also includes a molding compound, which is used to encapsulate the common-drain upper copper layer, the power chip, the source copper block, the L-shaped source lower copper layer and the bonding wire, with the upper surface of the common-drain upper copper layer and the lower surface of the L-shaped source lower copper layer partially exposed for heat dissipation and electrical connection.

[0012] Preferably, the drain copper terminal, the common drain upper copper layer, the two driving gate copper terminals, and the two driving source copper terminals are the same copper sheet with connections before processing. After welding, bonding, and encapsulation are completed, the connection between the drain copper terminal, the two driving gate copper terminals, and the two driving source copper terminals is cut off and bent downwards into a welding terminal. The welding surface of the welding terminal is located on the same plane as the lower surface of the L-shaped source lower copper layer.

[0013] Preferably, the mass production method of the common-drain module package structure with double-sided heat dissipation includes the following steps:

[0014] The common-drain upper copper layer is welded to the power chip, the power chip to the source copper block, and the source copper block to the L-shaped source lower copper layer in one step by vacuum reflow soldering.

[0015] The power chip's gate electrode is connected to the driving gate copper terminal and the power chip's source electrode is connected to the driving source copper terminal by bonding wires using a wire bonding machine.

[0016] Perform epoxy resin encapsulation and terminal cutting and bending.

[0017] Preferably, the power chip is a MOSFET or an IGBT.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] 1. This invention completely replaces the bulky power bonding wires with direct interconnection of copper blocks, and shortens the converter circuit through a compact modular layout, which significantly reduces the parasitic inductance of the circuit, helps to reduce switching overvoltage and electromagnetic interference, and improves the switching frequency;

[0020] 2. The double-sided heat dissipation structure of the present invention dissipates heat through a copper layer on the common drain electrode at the top of the module and through a copper layer on the lower L-shaped source electrode at the bottom, which significantly reduces the junction-to-loop thermal resistance and improves the power processing capability and power density of the module.

[0021] 3. This invention eliminates power bonding wires, avoiding the risk of breakage due to thermomechanical fatigue; the double-sided welding structure gives the module significant advantages in residual stress, chip stress, solder layer stress distribution, deformation control and plastic strain accumulation, effectively improving the reliability of the power module in service.

[0022] 4. The modular integrated design of this invention significantly reduces the size; although the amount of copper used increases slightly, it saves a lot of expensive thick bonding wires and reduces molding compound, and the estimated total cost is lower than that of two discrete devices.

[0023] 5. The packaging structure and process flow (welding-bonding-molding) proposed in this invention are compatible with existing mainstream packaging production lines and have the potential for large-scale production. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall structure of the common-drain module packaging structure for double-sided heat dissipation of the present invention.

[0026] Figure 2 This is a schematic diagram of the L-shaped source copper layer layout on the lower surface of the common-drain module with double-sided heat dissipation according to the present invention.

[0027] Figure 3 A schematic planar view of the source copper block layout for the common-drain module with double-sided heat dissipation of the present invention;

[0028] Figure 4 This is a schematic diagram of the chip and terminal layout of the common-drain module with double-sided heat dissipation of the present invention;

[0029] Figure 5 This is a schematic diagram of the longitudinal layout of the common-drain module with double-sided heat dissipation of the present invention;

[0030] Figure 6 This is a schematic diagram of the common drain topology corresponding to the common drain module packaging structure for double-sided heat dissipation of the present invention.

[0031] In the figure: 1. Copper layer on the common drain; 2. First drain copper terminal; 3. Second drain copper terminal; 4. First power chip; 5. Second power chip; 6. First drive gate copper terminal; 7. First drive source copper terminal; 8. Second drive gate copper terminal; 9. Second drive source copper terminal; 10. First source copper block; 11. First L-shaped source lower copper layer; 12. Second source copper block; 13. Second L-shaped source lower copper layer; 14a. Bonding wire; 14b. Bonding wire; 14c. Bonding wire; 14d. Bonding wire. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] like Figures 1 to 6 As shown, the present invention provides a common-drain module packaging structure with double-sided heat dissipation, including: a common-drain upper copper layer 1, a first drain copper terminal 2, a second drain copper terminal 3, a first power chip 4, a second power chip 5, a first source copper block 10, a second source copper block 12, a first L-shaped source lower copper layer 11, a second L-shaped source lower copper layer 13, a first driving gate copper terminal 6, a second driving gate copper terminal 8, a first driving source copper terminal 7, a second driving source copper terminal 9, and bonding wires; the drains of the first power chip 4 and the second power chip 5 are soldered to the same surface of the common-drain upper copper layer 1; the first source copper block 10 is soldered to the source surface of the first power chip 4, and the second source copper block 12 is soldered to the source surface of the second power chip 5; the first L-shaped source lower copper layer 11 is soldered to the first source copper block 10 and serves as the lead-out of the first power source terminal, and the second L-shaped source lower copper layer 13 is soldered to the first source copper block 10 and serves as the lead-out of the first power source terminal, and the second L-shaped source lower copper layer 13 is soldered to the first source copper block 10 and serves as the lead-out of the second ... Layer 13 is soldered to the second source copper block 12 and leads out as the second power source terminal; bonding wire 14a connects the gate electrode of the first power chip 4 to the first driving gate copper terminal 6, bonding wire 14b connects the source electrode of the first chip to the first driving source copper terminal 7, forming a Kelvin connection; bonding wire 14c connects the gate electrode of the second power chip 5 to the second driving gate copper terminal 8, bonding wire 14d connects the source electrode of the second power chip 5 to the second driving source copper terminal 9, forming a Kelvin connection; the upper surface of the common drain upper copper layer 1 is exposed for heat dissipation, and the lower surface portions of the first L-shaped source lower copper layer 11 and the second L-shaped source lower copper layer 13 are exposed for electrical connection and heat dissipation; the upper surface of the common drain upper copper layer 1 is used for direct mounting of heat sinks to achieve top heat dissipation; the lower surfaces of the first and second L-shaped source lower copper layers 13 are used to connect to the PCB for heat dissipation.

[0034] Figure 1 This is the overall structure of the packaging structure of the common drain module with double-sided heat dissipation provided in the embodiment of the present invention; the module as a whole includes a common drain upper copper layer 1, a power drain terminal, a power chip, a drive gate and source copper terminals, a source copper block, an L-shaped source lower copper layer and bonding wires.

[0035] like Figure 2 As shown, the bottom of the module includes a first L-shaped source under copper layer 11 and a second L-shaped source under copper layer 13, which correspond to the first power chip 4 and the second power chip 5 respectively, and are arranged in sequence.

[0036] like Figure 3 As shown, the first source copper block 10 and the second source copper block 12 are respectively connected to the first power chip 4 and the second power chip 5, and are located on the same layer.

[0037] Figure 4 This is a schematic diagram of the chip and terminal layout of the common drain module with double-sided heat dissipation provided in an embodiment of the present invention. The drains of the first power chip 4 and the second power chip 5 are jointly soldered to the copper layer 1 on the common drain. The copper layer 1 on the common drain has a first drain copper terminal 2 and a second drain copper terminal 3 on both sides. The first power chip 4, the first drain copper terminal 2, the first driving gate copper terminal 6, and the first driving source copper terminal 7 are located on the same side, and the second power chip 5, the second drain copper terminal 3, the second driving gate copper terminal 8, and the second driving source copper terminal 9 are located on the other side. The gate electrode of the first chip and the first driving gate copper terminal 6, the source electrode of the first chip and the first driving source copper terminal 7, the gate electrode of the second chip and the second driving gate copper terminal 8, and the source electrode of the second chip and the second driving source copper terminal 9 are connected by bonding wires 14a, 14b, 14c, and 14d, respectively.

[0038] Figure 5 This is a schematic diagram of the longitudinal layout of the common-drain module with double-sided heat dissipation provided in an embodiment of the present invention. The copper layer 1 on the common drain is located at the top layer of the module, the power chip is located below the copper layer 1 on the common drain, the source copper block is located below the power chip, and the L-shaped lower source copper layer is located below the source copper block, which is the bottom layer of the module. The first drain copper terminal 2, the second drain copper terminal 3, the first driving gate copper terminal 6, the second driving gate copper terminal 8, the first driving source copper terminal 7, and the second driving source copper terminal 9 are all bent from the top copper layer of the module to the bottom copper layer of the module as soldering pins. The first power chip 4, the first source copper block 10, the first L-shaped lower source copper layer 11, the first drain copper terminal 2, the first driving gate copper terminal 6, and the first driving source copper terminal 7 are located on one side of the module, and the second power chip 5, the second source copper block 12, the second L-shaped lower source copper layer 13, the second drain copper terminal 3, the second driving gate copper terminal 8, and the second driving source copper terminal 9 are located on the other side of the module.

[0039] Figure 6 This is a schematic diagram of the common-drain topology corresponding to the packaging structure provided in the embodiments of the present invention. The structure of the common-drain topology is similar to... Figures 1 to 5 Correspondingly, it consists of a common-drain upper copper layer 1, a first drain copper terminal 2, a second drain copper terminal 3, a first power chip 4, a second power chip 5, a first drive gate copper terminal 6, a first drive source copper terminal 7, a second drive gate copper terminal 8, a second drive source copper terminal 9, a first source copper block 10, a first L-shaped source lower copper layer 11, a second source copper block 12, a second L-shaped source lower copper layer 13, and the electrical connections between them.

[0040] This invention provides a dual-sided heat dissipation common-drain module packaging structure. This structure completely replaces traditional power bonding wires by employing copper block interconnect technology, soldering the drains of two power chips together on a large-area copper layer on the same drain, achieving electrical connection and top heat dissipation. Simultaneously, the source is connected to the L-shaped source copper layer via a source copper block, serving both as a power terminal and a bottom heat dissipation path, forming a highly efficient and collaborative dual-sided heat dissipation system. The large-area copper layer connection gives the module significant advantages in residual stress, chip stress, solder layer stress distribution, deformation control, and plastic strain accumulation, effectively improving the reliability of the power module. The module layout highly integrates the common-drain pair topology within a compact package. By optimizing chip arrangement and copper layer connections, the power commutation loop is significantly shortened, greatly reducing the module's parasitic inductance. Furthermore, the drive signals are led out from both sides of the chip using a Kelvin connection, effectively reducing the coupling effect between the drive circuit and the power circuit, decreasing the common source inductance, and improving drive stability. The module adopts a compact layout with power units arranged sequentially, which significantly reduces the package size. Its low inductance and low thermal resistance characteristics also provide an effective solution for achieving a common-drain power module with high power density and excellent high-frequency characteristics.

[0041] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-sided heat dissipation common-drain module package structure, characterized in that, The double-face heat dissipation common-drain module packaging structure comprises a common-drain upper copper layer (1), both ends of the common-drain upper copper layer (1) are provided with drain copper terminals, the drain copper terminals are the same copper layer as the common-drain upper copper layer (1), the bottom end of the common-drain upper copper layer (1) is fixedly connected with two power chips, the two power chips are both connected with driving gate copper terminals and driving source copper terminals, the bottom end of each of the two power chips is fixedly connected with a source copper block, the bottom end of the source copper block is fixedly connected with an L-shaped source lower copper layer, and the top end of the common-drain upper copper layer (1) and the bottom end of the L-shaped source lower copper layer are both connected with heat dissipation structures.

2. The dual-sided heat dissipating common-drain module package structure of claim 1, wherein, The heat dissipation structure at the top end of the common-drain upper copper layer (1) is a heat sink, and the heat dissipation structure at the bottom end of the L-shaped source lower copper layer is a PCB.

3. The dual-sided heat dissipating common-drain module package structure of claim 1, wherein, The two power chips are a first power chip (4) and a second power chip (5), and the common-drain upper copper layer (1), the source copper block and the L-shaped source lower copper layer corresponding to the first power chip (4), and the source copper block and the L-shaped source lower copper layer corresponding to the second power chip (5) jointly form a commutation loop.

4. The dual-sided heat dissipating common-drain module package structure of claim 1, wherein, The common-drain upper copper layer (1), the power chip, the power chip and the source copper block, and the source copper block and the L-shaped source lower copper layer are all welded by solder.

5. The dual-sided heat dissipating common-drain module package structure of claim 1, wherein, The driving gate copper terminal is connected with the gate electrode of the power chip by a bonding wire, and the driving source copper terminal is connected with the source electrode of the power chip by a bonding wire, thereby forming a Kelvin connection for reducing common-source inductance.

6. The dual-sided heat dissipating common-drain module package structure of claim 5, wherein, A plastic package is further included, which is used for encapsulating the common-drain upper copper layer (1), the power chip, the source copper block, the L-shaped source lower copper layer and the bonding wire, and the upper surface of the common-drain upper copper layer (1) and the lower surface of the L-shaped source lower copper layer are partially exposed for heat dissipation and electrical connection.

7. The dual-sided heat dissipating common-drain module package structure of claim 6, wherein, The drain copper terminal, the common-drain upper copper layer (1), the two driving gate copper terminals and the two driving source copper terminals are the same copper sheet with connections before processing, and after welding, bonding and plastic packaging, the connections between the drain copper terminal, the two driving gate copper terminals and the two driving source copper terminals are cut off and bent downward into welding terminals, and the welding surface of the welding terminal is located in the same plane as the lower surface of the L-shaped source lower copper layer.

8. The dual-sided heat dissipating common-drain module package structure of claim 7, wherein, The mass production processing method of the double-face heat dissipation common-drain module packaging structure comprises the following steps: The common-drain upper copper layer (1), the power chip, the power chip and the source copper block, and the source copper block and the L-shaped source lower copper layer are welded by vacuum reflow welding at one time; The gate electrode of the power chip and the driving gate copper terminal and the source electrode of the power chip and the driving source copper terminal are connected by a wire bonding machine; Epoxy resin plastic packaging and terminal shearing and bending are performed.

9. The dual-sided heat dissipating common-drain module packaging structure of claim 1, wherein, The power chip is a MOSFET or an IGBT.

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