Single-tube power chip with self-protection function and connection structure thereof

Abstract

This invention discloses a single-tube power chip with self-protection function and its connection structure, belonging to the field of power electronics technology. Addressing the failure risk of power modules exploding or catching fire under short-circuit conditions, the chip includes a chip body, electrodes, and a copper strip. The electrodes are positioned above the chip body, and the copper strip has a fusible aperture for melting and cutting off the circuit when overheated by short-circuit current. The copper strip and the electrodes are fixed together by a conductive connection layer. This invention employs a dual protection mechanism of software and hardware protection. The software protection responds rapidly within 0.1ms at the initial stage of a short circuit, while the hardware protection forcibly disconnects the circuit within 10ms via the copper strip's fusible aperture. Even if the software protection fails, the hardware protection still ensures system safety, achieving absolute safety protection against short-circuit interruption under 1000V high voltage. This completely avoids failures such as continuous arcing, explosion, and fire. The use of copper strip instead of traditional binding wire, combined with nano-silver sintering technology, significantly reduces the thermal resistance of the connection structure.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a single-tube power chip with self-protection function and its connection structure. Background Technology

[0002] In power electronic systems, the power module is a core component, and its reliability directly determines the operational safety of the entire system. Traditional power module chip connections use wire bonding, as shown in the attached diagram. Figure 1 The following technical defects exist in short-circuit protection:

[0003] 1. Insufficient reliability of bonding wires: Traditional aluminum / copper bonding wires are prone to fatigue fracture under long-term thermal cycling conditions, and the melting point of the bonding wire is random when a short circuit fault occurs, which cannot achieve a controllable protection effect and leads to a high risk of protection failure.

[0004] 2. Slow short-circuit protection speed: The response time of traditional fuses is usually in the millisecond range, while the fault current generated by the power chip during a short circuit rises very quickly. The millisecond-level response time cannot protect the fragile power chip in time, which can easily cause permanent damage to the chip.

[0005] 3. Potential for secondary disasters: During a short circuit, an electric arc may be generated during the melting of the bonding wire. The electric arc may cause the module to explode or catch fire, which may not only damage the equipment but also endanger personnel safety.

[0006] 4. Limited heat dissipation performance: The connection structure formed by traditional welding process has high thermal resistance, and the heat generated by the power chip during operation cannot be dissipated quickly, resulting in an increase in chip junction temperature, which affects the chip's working performance and lifespan.

[0007] In existing technologies, some solutions for short-circuit failures utilize external drive circuits for protection. However, due to factors such as circuit design, EMC design, and protection threshold settings, situations often arise where the software fails to promptly identify the short circuit or the protection circuit fails to trigger, leading to continuous short circuits. Power chips, wiring, and other components experience continuous arcing due to short-circuit failure, ultimately resulting in explosions and fires. Furthermore, while silver sintering processes and copper strip interconnect designs can improve heat dissipation to some extent, they fail to fundamentally solve the short-circuit protection problem. The lack of a reliable fuse protection mechanism cannot ensure the absolute safety of the power module under short-circuit faults.

[0008] Therefore, a single-tube power chip with self-protection function and its connection structure are needed to solve the problem of failure risk of power modules exploding and catching fire under short-circuit conditions in the existing technology. Summary of the Invention

[0009] The purpose of this invention is to provide a single-tube power chip with self-protection function and its connection structure to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a single-tube power chip with self-protection function, comprising a chip body, electrodes and a copper strip, characterized in that: the electrodes are disposed above the chip body, the copper strip is provided with a fusing slit for fusing to cut off the circuit when the short-circuit current overheats, and the copper strip and the electrodes are fixedly connected by a conductive connection layer.

[0011] It should be noted in the solution that the main body of the chip is a SiC MOSFET or IGBT structure.

[0012] It is worth noting that the shape of the fusion slit is one or more combinations of semicircle, circle, and ellipse.

[0013] It should be further noted that the copper strip has a thickness of 0.1-1.0 mm and is plated with a 2-5 μm silver layer.

[0014] In a preferred embodiment, the cross-sectional area reduction rate of the fusion slit is 30%-70%, and the slit spacing is 0.5-5mm.

[0015] In a preferred embodiment, the conductive connection layer is a nano-silver sintered layer with a thickness of 20-100 μm and a porosity of less than 5%.

[0016] A single-tube power chip connection structure with self-protection function is used to connect the aforementioned single-tube power chip with self-protection function. The structure includes a single-tube power chip and a ceramic copper-clad laminate. The single-tube power chip is fixedly connected to the ceramic copper-clad laminate through a nano-silver sintering layer, and the electrodes of the single-tube power chip and the electrodes of the ceramic copper-clad laminate are connected by a copper strip with upper and lower bridge arms.

[0017] In a preferred embodiment, the upper and lower bridge arms include an upper bridge arm and a lower bridge arm. The copper strip of the upper bridge arm is used to connect the emitter of the upper bridge single-tube power chip, the diode anode, and the copper-clad laminate electrode of the AC output terminal. The copper strip of the upper bridge arm is provided with a first narrow diameter 11, a second narrow diameter 12, and a third narrow diameter 13. The first narrow diameter 11 is located between the emitter of the upper bridge single-tube power chip and the copper-clad laminate electrode of the AC output terminal. The second narrow diameter 12 is located between the emitter of the upper bridge single-tube power chip and the diode anode. The third narrow diameter 13 is located between the diode anode and the copper-clad laminate electrode of the AC output terminal.

[0018] In a preferred embodiment, the lower bridge arm copper strip is used to connect the emitter of the lower bridge single-tube power chip, the diode anode, and the copper-clad laminate electrode of the high-voltage DC negative terminal. The lower bridge arm copper strip is provided with a fourth narrow diameter 14, a fifth narrow diameter 15, and a sixth narrow diameter 16. The fourth narrow diameter 14 is located between the emitter of the lower bridge single-tube power chip and the diode anode. The fifth narrow diameter 15 is located between the diode anode and the copper-clad laminate electrode of the high-voltage DC negative terminal. The sixth narrow diameter 16 is located between the lower bridge single-tube power chip and the copper-clad laminate electrode of the high-voltage DC negative terminal.

[0019] In a preferred embodiment, a tin block is provided next to the fusion slit to form an M-effect point.

[0020] Compared with the prior art, the single-transistor power chip and its connection structure with self-protection function provided by the present invention have at least the following beneficial effects:

[0021] Through the dual protection mechanism of software protection and hardware protection, the software protection responds quickly within 0.1ms in the initial stage of short circuit, and the hardware protection forcibly disconnects the circuit within 10ms by melting the narrow diameter of the copper strip. Even if the software protection fails, the hardware protection can still ensure system safety and achieve absolute safety protection for short circuit interruption under 1000V high voltage, completely avoiding failure phenomena such as continuous arcing, explosion and fire.

[0022] By using copper strips instead of traditional binding wires and combining them with nano-silver sintering technology, the thermal resistance of the connection structure is significantly reduced. The heat generated by the power chip can be quickly dissipated through the silver sintering layer, copper-clad laminate, and copper strip, effectively controlling the chip junction temperature and ensuring stable chip performance.

[0023] The nano-silver sintering process significantly enhances the adhesion between the chip and the ceramic copper-clad laminate. The copper strip interconnect design reduces the electrical stress on the chip electrodes, avoiding the detachment problem caused by electrical stress under high current, which is common with traditional wire bonding. At the same time, the copper strip undergoes annealing and silver plating, which further improves the mechanical stability and conductivity of the connection, increases power cycle life, and reduces connection resistance.

[0024] The connection structure integrates short-circuit protection, which can replace the high-voltage fuse in the traditional circuit. It eliminates the need for an additional independent fuse, simplifies the structural design of the power module, realizes the intelligent integration of the fuse and the power module, and improves the integration level and space utilization of the power module. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the conventional power module chip bonding connection structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the narrow diameter distribution of the copper strip melting point according to the present invention;

[0027] Figure 3 This is a schematic diagram of the overall assembly and heat dissipation path of the connection structure of the present invention;

[0028] Figure 4 This is a schematic diagram of the response timing of the dual protection system of the present invention;

[0029] Figure 5 This is a schematic diagram of the M-effect point setting in Embodiment 2 of the present invention.

[0030] In the diagram: 1. High voltage DC positive terminal; 2. AC output; 3. High voltage DC negative terminal; 11. First narrow aperture; 12. Second narrow aperture; 13. Third narrow aperture; 14. Fourth narrow aperture; 15. Fifth narrow aperture; 16. Sixth narrow aperture; 21. M-effect point. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments.

[0032] Example 1

[0033] refer to Figure 2 , Figure 3 and Figure 4 This invention provides a single-transistor power chip with self-protection function and its connection structure, comprising:

[0034] Single-tube power chip: SiC MOSFET or IGBT chip is selected as the chip body, and the electrodes on the surface of the chip body are connected to the copper strip plane.

[0035] Ceramic copper clad laminate: AlN or Al2O3 ceramic copper clad laminate is selected, which has good insulation performance and cost advantages, and is suitable for the heat dissipation requirements of medium power scenarios.

[0036] Copper strip design: The copper strip is made of oxygen-free copper with a thickness of 0.1-1.0mm and a silver plating layer thickness of 2-5μm. It is annealed at 400℃ for 1 hour and then processed by UV laser cutting to create 2-7 rows of fusion-breaking narrow diameters. The narrow diameters are designed with semi-circular, circular, and elliptical notches, with a cross-sectional area reduction rate of 30%-70% and a spacing of 0.5-5mm. The upper bridge arm copper strip is equipped with the first, second, and third narrow diameters, and the lower bridge arm copper strip is equipped with the fourth, fifth, and sixth narrow diameters.

[0037] Among them, replacing the binding wire with copper strip can greatly reduce the electrical stress conducted from the chip electrode to the binding wire, making the connection between the copper strip and the chip electrode more reliable. Because the output end of the chip electrode is a large surface and the bonding wire welding point is a small surface, when a large current is generated, the welding surface will generate electrical stress due to the rapid contraction of the current, which will cause the binding wire to detach, thereby generating an arcing point and causing more serious damage.

[0038] Nano-silver sintering process: Select nano-silver paste with silver particle size of 10-100nm and organic carrier content of 8%-15%. Under nitrogen or vacuum conditions, heat to 250℃ at a heating rate of 5-10℃ / min, apply sintering pressure of 10MPa, hold for 30 minutes, fix the chip on ceramic copper-clad laminate, and form a nano-silver sintered layer with a thickness of 20-100μm and a porosity of less than 5%.

[0039] Comparison of experimental data

[0040] Performance parameters Traditional technology This invention Increase Short circuit protection software Software + Hardware Absolutely safe thermal resistance 0.8K / W 0.5K / W 37.50% Power Cycle Life 10,000 times 50,000 times 5 times Connecting resistors 0.2mΩ 0.1mΩ 50%

[0041] The usage process of the above embodiment one is as follows:

[0042] In high-power scenarios, when a short-circuit fault occurs, the peak short-circuit current can reach over 2000A. In the initial stage of the short-circuit current (≤0.1ms), the external protection circuit quickly transmits a shutdown signal through an optocoupler isolation circuit to drive the gate of the power chip to turn off, thus achieving software protection. If the software protection fails, the short-circuit current continues to increase, and the current density at the narrow copper strip increases sharply. As the fault current continues to increase, the second protection will be activated. This is based on the fact that after the short-circuit current is generated, the circuit is broken by thermally melting through the first to sixth narrow strips in sequence, thereby avoiding current concentration and arcing caused by single-point melting. Therefore, it can prevent the system from continuously arcing under short-circuit current, or even failures such as explosion and fire. The combination design of ceramic copper-clad laminate and copper strip reduces the thermal resistance of the connection structure, ensuring temperature control of the power chip at rated power.

[0043] The dual protection system described in the above embodiments can achieve absolute safety of the system under short-circuit fault conditions. At the same time, because the solution has the feature of a hot-melt end, it can replace the high-voltage fuse in the circuit, achieving more intelligent and integrated advantages.

[0044] Dual protection system

[0045] Intelligent fuse protection system protection mechanism Response time Protect the scene First protection Software program protection Within 0.1ms Initial stage of short circuit current generation Second protection Hardware physical protection Within 10ms Mid-term short-circuit current

[0046] Example 2

[0047] Based on Example 1, such as Figure 5 As shown, a tin block is placed next to the narrow copper strip as an M-effect point to enhance the sensitivity and reliability of overcurrent protection. The tin block is made of pure tin (Sn100) with a melting point of 232℃. An M-effect point is added to the copper strip between the upper bridge arm power chip and the AC output terminal, and an M-effect point is added to the copper strip between the lower bridge arm power chip and the high voltage DC negative terminal. That is, the metallurgical effect is formed by the melting point of the tin block being lower than that of the narrow copper strip. The temperature can be higher than the melting point of the tin block but lower than the melting point of the copper strip. Through the metallurgical effect, the narrow strip can also melt quickly, thereby forming a certain overcurrent protection effect.

[0048] The usage process of the above embodiment two is as follows:

[0049] When a short-circuit fault occurs in a high-power scenario, and the software protection fails, the short-circuit current continues to increase. The current density at the narrow section of the copper strip rises sharply, and the temperature rises rapidly. When the temperature reaches 232°C, the pure tin block at the M-effect point melts and forms a metallurgical alloy with the copper strip. This lowers the melting temperature of the narrow section, achieving sequential thermal melting from the first to the sixth narrow section (from the end closest to the chip to the end closest to the copper-clad laminate). This avoids current concentration and arcing caused by single-point melting, thus preventing the system from continuously arcing under short-circuit current, or even exploding or catching fire. Since this process is a spontaneous melting due to the thermal effect of the current, there is no problem of being unable to protect.

[0050] In summary, the advantages of this invention are as follows: This invention employs a dual protection mechanism of software protection and hardware protection. The software protection responds rapidly within 0.1ms in the initial stage of a short circuit, while the hardware protection forcibly disconnects the circuit within 10ms by melting the narrow diameter of the copper strip. Even if the software protection fails, the hardware protection can still ensure system safety, achieving absolute safety protection for short circuit interruption under 1000V high voltage, and completely avoiding failure phenomena such as continuous arcing, explosion, and fire.

[0051] By using copper strips instead of traditional binding wires and combining them with nano-silver sintering technology, the thermal resistance of the connection structure is significantly reduced. The heat generated by the power chip can be quickly dissipated through the silver sintering layer, copper-clad laminate, and copper strip, effectively controlling the chip junction temperature and ensuring stable chip performance.

[0052] The nano-silver sintering process significantly enhances the adhesion between the chip and the ceramic copper-clad laminate. The copper strip interconnect design reduces the electrical stress on the chip electrodes, avoiding the detachment problem caused by electrical stress under high current, which is common with traditional wire bonding. At the same time, the copper strip undergoes annealing and silver plating, which further improves the mechanical stability and conductivity of the connection, increases power cycle life, and reduces connection resistance.

[0053] The connection structure integrates short-circuit protection, which can replace the high-voltage fuse in the traditional circuit. It eliminates the need for an additional independent fuse, simplifies the structural design of the power module, realizes the intelligent integration of the fuse and the power module, and improves the integration level and space utilization of the power module.

[0054] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A single-transistor power chip with self-protection function, comprising a chip body, electrodes, and copper strip, characterized in that: The electrode is disposed above the chip body, and the copper strip has a fusible slit for melting and cutting off the circuit when the short-circuit current overheats. The copper strip and the electrode are fixed together by a conductive connection layer.

2. A single-transistor power chip with self-protection function according to claim 1, characterized in that: The main body of the chip is a SiC MOSFET or IGBT structure.

3. A single-transistor power chip with self-protection function according to claim 1, characterized in that: The shape of the fusion slit is one or more combinations of semicircle, circle, and ellipse.

4. A single-transistor power chip with self-protection function according to claim 1, characterized in that: The copper strip has a thickness of 0.1-1.0 mm and is plated with a 2-5 μm silver layer.

5. A single-transistor power chip with self-protection function according to claim 3, characterized in that: The cross-sectional area reduction rate of the fusion slit is 30%–70%, and the slit spacing is 0.5–5 mm.

6. A single-transistor power chip with self-protection function according to claim 1, characterized in that: The conductive connection layer is a nano-silver sintered layer with a thickness of 20-100μm and a porosity of less than 5%.

7. A single-transistor power chip connection structure with self-protection function, used to connect a single-transistor power chip with self-protection function as claimed in any one of claims 1-6, comprising a single-transistor power chip and a ceramic copper-clad laminate, characterized in that: The single-tube power chip is fixedly connected to the ceramic copper-clad plate through a nano-silver sintering layer, and the electrodes of the single-tube power chip and the electrodes of the ceramic copper-clad plate are connected by a copper strip with upper and lower bridge arms.

8. A single-transistor power chip connection structure with self-protection function according to claim 7, characterized in that: The upper and lower bridge arms include an upper bridge arm and a lower bridge arm. The copper strip of the upper bridge arm is used to connect the emitter of the upper bridge single-tube power chip, the diode anode, and the copper-clad laminate electrode of the AC output terminal. The copper strip of the upper bridge arm is provided with a first narrow diameter 11, a second narrow diameter 12, and a third narrow diameter 13. The first narrow diameter 11 is located between the emitter of the upper bridge single-tube power chip and the copper-clad laminate electrode of the AC output terminal. The second narrow diameter 12 is located between the emitter of the upper bridge single-tube power chip and the diode anode. The third narrow diameter 13 is located between the diode anode and the copper-clad laminate electrode of the AC output terminal.

9. A single-transistor power chip connection structure with self-protection function according to claim 7, characterized in that: The lower bridge arm copper strip is used to connect the emitter of the lower bridge single-tube power chip, the diode anode, and the copper-clad laminate electrode of the high-voltage DC negative terminal. The lower bridge arm copper strip is provided with a fourth narrow diameter 14, a fifth narrow diameter 15, and a sixth narrow diameter 16. The fourth narrow diameter 14 is located between the emitter of the lower bridge single-tube power chip and the diode anode. The fifth narrow diameter 15 is located between the diode anode and the copper-clad laminate electrode of the high-voltage DC negative terminal. The sixth narrow diameter 16 is located between the lower bridge single-tube power chip and the copper-clad laminate electrode of the high-voltage DC negative terminal.

10. A single-transistor power chip connection structure with self-protection function according to claim 5, characterized in that: A tin block is provided next to the fusion-breaking narrow diameter to form an M-effect point.

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