Packaging structure of semiconductor module

Abstract

The invention discloses a packaging structure of a semiconductor module, and belongs to the technical field of module packaging. Comprising a heat dissipation substrate and an injection molding integrated shell connected with the heat dissipation substrate, a containing space is formed between the heat dissipation substrate and the injection molding integrated shell, and a copper substrate is arranged in the containing space and arranged on the heat dissipation substrate; the power chip is welded on the copper substrate through a first solder; the terminal is ultrasonically welded on the copper substrate through a second solder; an opening structure is arranged at the top of the injection molding integrated shell and used for injecting an insulating layer into the containing space. The beneficial effects of the above technical scheme are that the terminals are attached to the circuit board, different layout requirements can be flexibly satisfied, the sealing performance and the insulating performance of the packaging structure are strong, the heat dissipation effect is good, and the integrated housing design can reduce the number of parts and simplify the production process.

Description

Technical Field

[0001] The present invention relates to the technical field of module packaging, and in particular to a packaging structure. Background Art

[0002] With the continuous development of new energy vehicle technology, IGBT (Insulate-Gate Bipolar Transistor) modules are increasingly used in the field of new energy vehicles. The performance of power semiconductor modules directly affects the power release and driving efficiency of new energy vehicles. Therefore, the requirements for the structure, circuit reliability and integration of power modules are also gradually increasing.

[0003] In the prior art, the terminals of the IGBT module are usually injection molded on the module housing and cannot be moved later; the module operates for a long time under high voltage, high current and complex working environment, the flat substrate cannot fully solve the heat dissipation problem caused by high power operation, and the module packaging structure has poor airtightness and insulation, which affects the stability and life of the module; at the same time, the existing modules have many parts and the production process is complicated. Summary of the invention

[0004] The object of the present invention is to provide a packaging structure of a semiconductor module to solve the above technical problems;

[0005] A semiconductor module packaging structure, comprising:

[0006] A heat dissipation substrate and an injection-molded integral shell connected to the heat dissipation substrate, wherein an accommodation space is provided between the heat dissipation substrate and the injection-molded integral shell, and within the accommodation space,

[0007] A copper substrate, disposed on the heat dissipation substrate;

[0008] A power chip is soldered on the copper substrate by a first solder;

[0009] A terminal is ultrasonically welded to the copper substrate by a second solder;

[0010] The top of the injection-molded integral housing is provided with an opening structure for injecting an insulating layer into the accommodating space.

[0011] Preferably, the terminal is made of pure copper or copper alloy, at least a portion of the terminal extends out of the top of the injection-molded housing to form a pin, the pin is cylindrical, and the surface of the pin is electroplated with metal material, and the metal material includes gold, nickel and tin.

[0012] Preferably, a thermistor is further provided in the accommodating space and is soldered to the copper substrate by a third solder;

[0013] A metal wire is ultrasonically bonded and welded between the power chip, the terminal and the thermistor;

[0014] The metal wire is made of materials including pure aluminum and aluminum alloy materials.

[0015] Preferably, heat dissipation fins are provided on the back side of the heat dissipation substrate.

[0016] Preferably, the injection-molded integrated housing is made of materials including polybutylene terephthalate, polyphenylene sulfide and polyamide.

[0017] Preferably, the opening structure is circular, the insulating layer is insulating silicone gel, and the insulating layer is arranged on the surfaces of the copper substrate, the power chip, the terminal and the thermistor.

[0018] Preferably, a sealant is provided between the heat dissipation substrate and the integral injection-molded housing.

[0019] Preferably, the power chip includes an insulated gate bipolar transistor and a diode chip;

[0020] The first solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy;

[0021] The soldering temperature of the first solder is 100°C to 400°C.

[0022] Preferably, the second solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy;

[0023] The soldering temperature of the second solder is 100°C to 400°C.

[0024] Preferably, the third solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy;

[0025] The welding temperature of the third solder is 100°C to 400°C.

[0026] The beneficial effects of the present invention are as follows: the terminals are attached to the circuit board, which can flexibly meet different layout requirements; the packaging structure has strong sealing and insulation properties, good heat dissipation effect, and the integrated shell design can reduce the number of parts and simplify the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the internal structure of a semiconductor module of the present invention;

[0028] Figure 2 is a cross-sectional view of a packaging structure of a semiconductor module of the present invention;

[0029] Figure 3 is a perspective view of a packaging structure of a semiconductor module of the present invention;

[0030] Figure 4 is a bottom view of the heat dissipation substrate of the present invention;

[0031] Figure 5 It is a top view of the packaging structure of the semiconductor module of the present invention.

[0032] In the attached drawings: 1. heat dissipation substrate; 11. heat dissipation fins; 2. injection-molded integrated housing; 3. copper substrate; 4. power chip; 5. terminal; 51. pin; 6. thermistor; 7. opening structure; 8. insulation layer. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0036] A semiconductor module packaging structure, such as Figure 1 , Figure 2 As shown, including

[0037] A heat dissipation substrate 1 and an injection-molded integral housing 2 connected to the heat dissipation substrate 1, a containing space is provided between the heat dissipation substrate 1 and the injection-molded integral housing 2, and the containing space is provided with:

[0038] The copper substrate 3 is provided on the heat dissipation substrate 1;

[0039] The power chip 4 is soldered on the copper substrate 3 by a first solder;

[0040] The terminal 5 is ultrasonically welded to the copper substrate 3 by a second solder;

[0041] An opening structure 7 is provided on the top of the injection-molded integral housing 2 for injecting an insulating layer 8 into the accommodating space.

[0042] Specifically, the present invention provides a packaging structure of a semiconductor module, in which a power chip 4 and a terminal 5 are respectively fixed on the conductive copper layer of a copper substrate 3 by welding. The copper substrate 3 is a direct copper bonding substrate. The terminal 5 is attached to a circuit board and is not injection molded on a shell. It can flexibly meet different layout requirements, improve contact performance, and reduce contact resistance, thereby improving the stability and reliability of the circuit. An injection-molded integrated shell 2 is fixed to the outer side of the direct copper bonding substrate at the edge of a heat dissipation substrate 1, thereby ensuring the stability and airtightness of the packaging structure body. Compared with the packaging structure of a shell plus a cover, the injection-molded integrated shell 2 can reduce the number of parts and production processes while ensuring airtightness. The opening structure 7 is used to inject an insulating layer 8, thereby improving the insulation withstand voltage performance.

[0043] In a preferred embodiment, referring to Figure 3 , Figure 5 The terminal 5 is made of pure copper or copper alloy. At least a portion of the terminal 5 extends out of the top of the injection-molded housing 2 to form a pin 51. The pin 51 is cylindrical. The surface of the pin 51 is electroplated with metal materials, including gold, nickel and tin.

[0044] Specifically, the terminal 5 includes a signal terminal and a power terminal. At least a portion of the terminal 5 extends out of the top of the injection-molded housing 2. The exposed portion is a column, which is used to improve contact performance and save space. The surface of the exposed portion of the terminal 5 is plated to improve welding performance.

[0045] The independent column terminal 5 can meet various layout requirements, so that the pins of the components are more closely attached to the surface of the circuit board. Compared with other patch technologies, the column structure can greatly save the space of the circuit board, reduce the volume of the circuit board, and increase the thickness of the circuit board, meeting the development needs of lighter and smaller electronic products.

[0046] Gold has excellent electrical conductivity and does not oxidize, so it can provide a stable electrical connection and avoid increased resistance that affects signal transmission. Gold's good conductivity ensures low resistance in electrical connections, reducing signal attenuation or energy loss.

[0047] Nickel has strong antioxidant ability and can effectively protect metals from the external environment (such as moisture, oxygen, salt spray, etc.) to avoid corrosion or oxidation. Tin is also one of the anti-corrosion materials, especially widely used in electronic components to prevent oxidation and maintain long-term contact stability.

[0048] The nickel layer usually serves as the base layer of gold, which can effectively prevent gold from direct contact with substances in the environment, thereby avoiding oxidation or deterioration of the gold surface; the tin layer helps to further improve corrosion resistance, especially during the welding process, tin can improve the stability of the welding joints.

[0049] The alloy structure of gold, nickel and tin can not only improve the conductivity, but also enhance the surface hardness of the pins, making them more wear-resistant and avoiding damage to the pin surface caused by frequent plugging or friction.

[0050] The flexibility of gold and the oxidation resistance of tin combined with the hardness of nickel can improve the durability of the pins and avoid poor contact or wear during use.

[0051] One of the main functions of tin is to improve solderability. Coating a tin layer on the surface can improve the reliability of soldering points and ensure the long-term stable operation of electronic components.

[0052] The low melting point of tin makes the soldering operation easier, while also enhancing the mechanical connection strength of the solder joints and preventing soldering failure due to overheating or improper operation.

[0053] In a preferred embodiment, a thermistor 6 is further provided in the accommodation space and is soldered to the copper substrate 3 by a third solder;

[0054] Metal wires are ultrasonically bonded between the power chip 4, the terminal 5 and the thermistor 6;

[0055] The materials used to make the metal wire include pure aluminum and aluminum alloy materials.

[0056] Specifically, the power chip 4, the terminal 5 and the thermistor 6 are electrically connected by metal wire bonding. Aluminum has good electrical conductivity, second only to copper. Using aluminum or aluminum alloy as the metal wire material can ensure low resistance, thereby improving current transmission efficiency and ensuring the stability of the electrical connection between the power chip 4, the terminal 5 and the thermistor 6.

[0057] Compared to copper, aluminum has a lower density, so aluminum alloy or pure aluminum metal wire has a lighter weight, reducing the weight of the overall module and improving the portability and heat dissipation performance of the device.

[0058] Aluminum easily forms a dense oxide film in the air, which can effectively prevent further oxidation of aluminum metal. Therefore, aluminum or aluminum alloy metal wire has good corrosion resistance and is suitable for applications in harsh environments, such as high humidity or high temperature environments.

[0059] Aluminum is cheaper than copper and has abundant resources. Using aluminum as a metal wire material can significantly reduce production costs.

[0060] In a preferred embodiment, referring to Figure 4 A heat dissipation fin 11 is provided on the back side of the heat dissipation substrate 1 .

[0061] Specifically, the heat dissipation substrate 1 is a PINFIN substrate structure, and has a better heat dissipation effect than a flat substrate, so that the module can obtain a better heat dissipation effect.

[0062] The PINFIN structure generally refers to a large number of slender metal fins (usually cylindrical, fin-shaped or needle-shaped structures) formed on the back side of the substrate or the heat dissipation surface. The fins can increase the heat dissipation surface area.

[0063] Heat is transferred from the substrate to the fins by thermal conduction, so that the diffusion and dissipation speed of heat is proportional to the contact area. The heat dissipation fins 11 significantly increase the heat dissipation area, thereby greatly improving the heat release efficiency and effectively reducing the operating temperature of the module.

[0064] The heat dissipation fins 11 are cylindrical and have a large surface area. The cylindrical shape facilitates air flow and enhances the convection heat dissipation effect.

[0065] The curved surface of the cylindrical fins can reduce air resistance, allowing air flow to pass more easily, thereby accelerating the removal of heat.

[0066] Compared with flat or square fins, the cylindrical structure can provide more heat dissipation area in the same space, effectively improving the efficiency of heat conduction and diffusion, thereby reducing module temperature and improving heat dissipation performance.

[0067] On a flat substrate without fins, heat may be concentrated in a certain area, causing local overheating. With the fin design, the heat can be dispersed more evenly to avoid local heat accumulation.

[0068] In a preferred embodiment, the injection-molded integrated housing 2 is made of materials including polybutylene terephthalate, polyphenylene sulfide and polyamide, which have the effects of high temperature resistance and good insulation performance.

[0069] Specifically, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS) and polyamide (PA) are all high-performance engineering plastics with high glass transition temperature (Tg) and melting point. They will not soften, deform or degrade under high temperature conditions, thus providing long-term and stable protection under high temperature working conditions.

[0070] These materials contain fewer free carriers in their molecular structure, so they can effectively isolate the flow of current, prevent current from flowing on the surface of the shell, and ensure the electrical safety of electronic equipment. In addition, the electrical insulation properties of these materials can remain stable at higher temperatures.

[0071] The molecular chain structure of polyphenylene sulfide (PPS) and polyamide (PA) has strong rigidity and strength, can maintain stable shape when subjected to force, and has good wear resistance in friction environments, making it suitable for applications that require impact resistance and wear resistance.

[0072] The molecular structure of these materials has high chemical stability and can avoid chemical reactions or corrosion when exposed to acids, alkalis or other chemicals.

[0073] For example, PPS has excellent chemical resistance due to its strong aromatic ring structure and the stability of thioether bonds.

[0074] In a preferred embodiment, the opening structure 7 is circular, the insulating layer 8 is insulating silicone gel, and the insulating layer 8 is disposed on the surface of the copper substrate 3 , the power chip 4 , the terminal 5 and the thermistor 6 .

[0075] Specifically, the circular opening structure 7 facilitates the injection of insulating silicone gel into the housing, thereby reducing the overall complexity.

[0076] The insulating layer 8 completely covers the power chip 4 , the terminals 5 , the thermistor 6 , and the metal wires, and also covers the base welding area between the power terminals and the signal terminals and the copper substrate 3 .

[0077] The insulating silicone gel can improve the insulation withstand voltage performance of the base welding area between the power chip 4 , the thermistor 6 , the metal wire and the terminal 5 and the copper substrate 3 .

[0078] In a preferred embodiment, a sealant is provided between the heat dissipation substrate 1 and the injection-molded integral housing 2 .

[0079] Specifically, the injection-molded integrated housing 2 and the heat dissipation substrate 1 are bonded by means of sealant and fixedly connected by means of screws to ensure overall stability.

[0080] The use of sealant can effectively prevent external dust, moisture, etc. from entering the interior, provide better protection, and avoid corrosion and damage to internal components caused by environmental factors.

[0081] Sealant can provide a certain buffering effect, reduce the loosening or damage of components caused by vibration or impact, and enhance the stability and impact resistance of the structure.

[0082] The contact area between the sealant and the heat dissipation substrate 1 can help to better conduct heat, especially has a certain adaptability in thermal expansion, ensuring that heat can be effectively conducted from the heat dissipation substrate to the casing, thereby improving heat dissipation efficiency and reducing the risk of equipment overheating.

[0083] The dual connection method of screws and sealant ensures the firm fixation between the shell and the baseboard, preventing the equipment from loosening or poor contact due to long-term use, thereby ensuring the long-term stability and reliability of the equipment.

[0084] The sealant has a certain degree of flexibility and can adapt to deformation caused by thermal expansion and other reasons, reducing mechanical stress concentration and extending the service life of the component.

[0085] In a preferred embodiment, the power chip 4 includes an insulated gate bipolar transistor and a diode chip; the insulated gate bipolar transistor (IGBT) combines the high input impedance of a MOSFET (field effect transistor) and the high current carrying capacity of a bipolar transistor, and is capable of performing efficient switching control in a high voltage and high current environment.

[0086] IGBT has a lower on-resistance, so it can reduce power loss and improve efficiency when it is turned on.

[0087] When the IGBT is in the on state, the smaller on resistance reduces power loss; in the off state, the switching speed is faster, which reduces the energy loss during switching, thereby improving the overall efficiency.

[0088] During the power conversion process, when the current direction changes, the diode can act as a freewheeling device, conducting when the current is reversed to protect the power device from the influence of reverse current. The diode can effectively reduce the reverse recovery loss in the switching operation and improve the efficiency of the switch.

[0089] The diode provides a fast reverse current channel for the IGBT, especially during high-frequency switching. The diode can effectively suppress the interference of reverse current, thereby reducing the reverse recovery time and switching loss.

[0090] By combining the IGBT and the diode together, the power chip 4 can achieve lower switching losses and smaller conduction losses, thereby reducing the thermal load of the device during operation.

[0091] The IGBT provides efficient power conversion, while the diode works in conjunction to reduce losses when current is switched, so the system can run at higher power without generating excessive heat, improving overall efficiency.

[0092] The switching operation of the insulated gate bipolar transistor combined with the reverse current control of the diode can greatly improve the stability of the entire power control system and avoid problems caused by reverse current or high-frequency switching.

[0093] The presence of the diode helps prevent reverse current from damaging the IGBT, reducing the risk of failure due to reverse current. The integration of IGBT and diode enables the system to withstand higher voltage and current, ensuring long-term stable operation.

[0094] Integrating IGBT and diode on the same chip not only improves the power conversion efficiency, but also reduces the complexity of the external circuit, making the entire power chip smaller and more integrated, suitable for application scenarios with limited space.

[0095] Integrated circuit design reduces the connections and layout between chips, optimizes space utilization, reduces circuit complexity and cost, and improves system reliability.

[0096] IGBTs are capable of handling higher voltages and frequencies, while diodes can quickly respond to changes in current direction, adapting to a wider range of operating conditions and meeting the needs of efficient power conversion.

[0097] IGBT and diode work together to enable the power chip to operate stably under a wide range of input voltage and frequency conditions, adapting to different application requirements (such as electric vehicles, industrial drives, power inverters, etc.).

[0098] The first solder is a tin-lead alloy or a tin-silver alloy or a tin-silver-copper alloy or a lead-tin-silver alloy; the chip part of the insulated gate bipolar transistor and the diode and the copper substrate 3 (DBC) are connected by soldering using one of SnPb, SnAg, SnAgCu, and PbSnAg;

[0099] The welding temperature of the first solder is 100°C to 400°C;

[0100] The second solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy; the terminal 5 and the copper substrate 3 (DBC) are connected by ultrasonic or welding using one of SnPb, SnAg, SnAgCu, and PbSnAg;

[0101] The welding temperature of the second solder is 100°C to 400°C;

[0102] The third solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy; the thermistor 6 and the copper substrate 3 (DBC) are connected by welding using one of SnPb, SnAg, SnAgCu, and PbSnAg;

[0103] The soldering temperature of the third solder is 100°C to 400°C.

[0104] Specifically, solders such as tin-lead alloy, tin-silver alloy, tin-silver-copper alloy, etc. have good fluidity and low melting point, which can effectively ensure the connection stability between the chip and the substrate. They can balance the fluidity and strength during the welding process, reduce the void rate of the solder joints, and improve the reliability of the solder joints.

[0105] The welding temperature of 100℃~400℃ can meet the welding requirements of different materials and avoid damage to components caused by too high or too low temperature. The power chip 4 will be affected by temperature and thermal stress. A reasonable welding temperature range can ensure that the components are not subjected to excessive thermal stress during the welding process, while avoiding material damage or performance degradation caused by excessive temperature.

[0106] Using the right solder ensures lower resistance between the chip and the substrate, thus improving the efficiency of the overall power module. Tin-silver alloys (such as SnAg) have good electrical and thermal conductivity, which helps improve the thermal management capabilities of the power module and reduce high temperature damage.

[0107] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A semiconductor module packaging structure, characterized in that: include, A heat dissipation substrate and an injection-molded integral shell connected to the heat dissipation substrate, wherein an accommodation space is provided between the heat dissipation substrate and the injection-molded integral shell, and within the accommodation space, A copper substrate, disposed on the heat dissipation substrate; A power chip is soldered on the copper substrate by a first solder; A terminal is ultrasonically welded to the copper substrate by a second solder; The top of the injection-molded integral housing is provided with an opening structure for injecting an insulating layer into the accommodating space.

2. The semiconductor module packaging structure according to claim 1, characterized in that: The terminal is made of pure copper or copper alloy. At least a portion of the terminal extends out of the top of the injection-molded housing to form a pin. The pin is cylindrical and the surface of the pin is electroplated with metal material, which includes gold, nickel and tin.

3. The semiconductor module packaging structure according to claim 1, characterized in that: The accommodating space is also provided with a thermistor, which is soldered to the copper substrate by a third solder; A metal wire is ultrasonically bonded and welded between the power chip, the terminal and the thermistor; The metal wire is made of materials including pure aluminum and aluminum alloy materials.

4. The semiconductor module packaging structure according to claim 1, characterized in that: The back side of the heat dissipation substrate is provided with heat dissipation fins.

5. The semiconductor module packaging structure according to claim 1, characterized in that: The materials used to make the injection-molded integrated housing include polybutylene terephthalate, polyphenylene sulfide and polyamide.

6. The semiconductor module packaging structure according to claim 3, characterized in that: The opening structure is circular, the insulating layer is insulating silicone gel, and the insulating layer is arranged on the surfaces of the copper substrate, the power chip, the terminal and the thermistor.

7. The semiconductor module packaging structure according to claim 1, characterized in that: A sealant is provided between the heat dissipation substrate and the injection-molded integral housing.

8. The semiconductor module packaging structure according to claim 1, characterized in that: The power chip includes an insulated gate bipolar transistor and a diode chip; The first solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy; The soldering temperature of the first solder is 100°C to 400°C.

9. The semiconductor module packaging structure according to claim 1, characterized in that: The second solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy; The soldering temperature of the second solder is 100°C to 400°C.

10. The semiconductor module packaging structure according to claim 3, characterized in that: The third solder is a tin-lead alloy, a tin-silver alloy, a tin-silver-copper alloy, or a lead-tin-silver alloy; The welding temperature of the third solder is 100°C to 400°C.

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