Temperature measuring and packaging integrated device and method for crimping IGBT chip

Abstract

The invention belongs to the field of chips and chip integration packaging, and particularly discloses a temperature measuring and packaging integration device and method for a crimped IGBT chip, the temperature measuring device is applied to a crimped IGBT device, the crimped IGBT device comprises an IGBT chip and an emitter molybdenum sheet, the IGBT chip comprises a grid electrode bonding pad and an emitter electrode bonding pad, the grid electrode bonding pad and the emitter electrode bonding pad are located on the front face of the chip, and the emitter electrode bonding pad is located on the front face of the chip. And the emitter molybdenum sheet is attached to the emitter bonding pad. The measuring device comprises: a temperature sensor; the temperature sensor is used for measuring the temperature of the IGBT chip when the temperature sensor is arranged in a gap between a grid electrode bonding pad on the front surface of the IGBT chip and a preset area; the preset area is an area, covered by the emitter molybdenum sheet, of the front surface of the IGBT chip. According to the invention, the temperature sensor is installed at the gap between the emitter molybdenum sheet and the chip grid bonding pad, and the maximum temperature of the surface of the IGBT chip can be directly monitored after the pressure of the crimping IGBT module is saturated.

Description

Technical Field

[0001] The present application belongs to the field of chips and chip integrated packaging, and more specifically, to a temperature measurement, packaging integration device and method for a crimped insulated-gate bipolar transistor (IGBT) chip. Background Art

[0002] Press-fit packaged insulated gate bipolar transistors (PP IGBTs) are widely used in flexible DC converter valves, high-voltage DC circuit breakers, and static synchronous compensators. Compared with traditional welded packaged IGBTs, PP IGBTs have the advantages of high power density, double-sided cooling, low parasitic inductance, easy series connection, and fault short circuit. As the most vulnerable component in the power conversion system, the reliability of PP IGBTs has attracted widespread attention. Among the various failure factors of power semiconductors, overheating failure accounts for the highest proportion. Online monitoring of PP IGBT junction temperature helps to extend the life of the device and improve the formulation of maintenance strategies for flexible DC transmission systems. Existing junction temperature monitoring methods can be divided into: physical contact measurement method, optical non-contact measurement method, thermal impedance model prediction method, and temperature sensitive electrical parameter (TSEP) method.

[0003] Compared with the other three methods, the physical contact measurement method can directly and accurately obtain the chip temperature. After the temperature sensor is integrated with the IGBT chip package and installed in a reasonable position, the temperature sensor embedded in the crimped IGBT module can directly monitor the maximum temperature of the IGBT chip.

[0004] Furthermore, the existing document 1: Quasi-Distributed Temperature Detection of Press-Pack IGBT Power Module Using FBG Sensing proposes to insert an optical fiber into the elastically pressed IGBT molybdenum sheet and extract the chip temperature through the optical fiber. However, since this position will be affected by stress, the optical Bragg grating temperature measurement will be affected by pressure. This method must eliminate the influence of pressure on the optical fiber monitoring results. The existing document 2: Experimental Verification of the Junction Temperature Distribution within Press Pack IGBTs proposes to groove the molybdenum sheet of the press-packed IGBT emitter and insert a thermocouple. However, filling the emitter molybdenum sheet with glue after the groove is opened will increase the thermal resistance of the press-packed IGBT module and increase the chip operating temperature. The existing document 3: Thermal Contact Resistance Optimization of Press-Pack IGBT Device Based on Liquid Metal Thermal Interface Material proposes to insert a thermocouple at the edge of the press-packed IGBT submodule, but this position is located at the edge of the chip terminal. The chip terminal does not belong to the active area and the temperature is relatively low, far lower than the maximum temperature of the chip.

[0005] In summary, the existing physical contact measurement method cannot accurately measure the maximum temperature of the crimped IGBT chip. Summary of the invention

[0006] In view of the defects of the prior art, the purpose of this application is to provide a temperature measurement and packaging integrated device and method for a crimped IGBT chip, aiming to solve the problem that the existing physical contact measurement method cannot accurately measure the maximum temperature of the crimped IGBT chip.

[0007] To achieve the above-mentioned purpose, in a first aspect, the present application provides a temperature measurement device for a crimped IGBT chip, wherein the crimped IGBT device comprises: an IGBT chip and an emitter molybdenum sheet, wherein the IGBT chip comprises: a gate pad and an emitter pad, wherein the gate pad and the emitter pad are located on the front side of the chip, and the emitter molybdenum sheet is attached to the emitter pad; the measurement device comprises: a temperature sensor;

[0008] The temperature sensor, when arranged in the gap between the gate pad and a preset area on the front side of the IGBT chip, is used to measure the temperature of the IGBT chip; the preset area is the area on the front side of the IGBT chip covered by the emitter molybdenum sheet, and the preset area is adjacent to the gate pad.

[0009] It should be noted that usually the crimped IGBT device works under the pressure saturation state, and according to the conventional thinking in this field, due to the thermal coupling effect, the maximum temperature of the general device is usually at the center of the device. Therefore, the existing physical contact measurement method is to set a temperature sensor in the center of the emitter molybdenum sheet to measure the temperature. After research, it was found that the temperature measured at this time is not the maximum temperature, and the groove method of the emitter molybdenum sheet will increase the operating temperature of the chip. The present application found that the maximum temperature of the IGBT chip under the pressure saturation state of the crimped IGBT device is in the gap between the gate pad and the area covered by the emitter molybdenum sheet. Therefore, a temperature sensor is directly set here, without the need to groove the emitter molybdenum sheet, and no additional temperature rise is introduced. The temperature can be directly measured here, and the measured temperature value is relatively accurate, which can accurately reflect the maximum temperature of the crimped IGBT chip.

[0010] In a possible implementation, the emitter molybdenum sheet has a corner, and the gate pad is adjacent to an area covered by the corner; when the temperature sensor is used to measure the temperature of the IGBT chip, its probe penetrates into the area around the corner.

[0011] Generally, when the press-bonded IGBT device operates under a pressure saturation state, the temperature of the IGBT chip at the above-mentioned corner is the highest.

[0012] In a possible implementation, when the clamping force applied to the press-bonded IGBT chip is greater than a preset value, the temperature measured by the temperature sensor corresponds to the maximum temperature of the IGBT chip.

[0013] It should be noted that the above preset value may be the clamping force required when the pressure-connected IGBT device is pressure-saturated, and pressure saturation means that the clamping force is greater than a critical mechanical pressure. Usually, the pressure-connected IGBT device needs to work in a pressure-saturated state.

[0014] In a possible implementation, no additional temperature sensor needs to be provided in the emitter molybdenum sheet.

[0015] In a second aspect, the present application provides a press-bonded IGBT chip, comprising the temperature measuring device described in the first aspect or any possible implementation of the first aspect, wherein the temperature sensor is arranged at the gap.

[0016] In a third aspect, the present application provides a packaging and integration device for crimping an IGBT chip, comprising: a crimped IGBT device and a temperature measurement device as described in the first aspect or any possible implementation of the first aspect;

[0017] The temperature sensor is arranged at the gap, and the temperature sensor is synchronously packaged and integrated with the press-fit IGBT device.

[0018] In a fourth aspect, the present application provides a temperature measurement method for a crimped IGBT chip, wherein the crimped IGBT device comprises: an IGBT chip and an emitter molybdenum sheet, wherein the IGBT chip comprises: a gate pad and an emitter pad, wherein the gate pad and the emitter pad are located on the front side of the chip, and the emitter molybdenum sheet is bonded to the emitter pad; the method comprises:

[0019] A temperature sensor is arranged in the gap between the gate pad and a preset area on the front side of the IGBT chip to measure the temperature of the IGBT chip; the preset area is the area on the front side of the IGBT chip covered by the emitter molybdenum sheet, and the preset area is adjacent to the gate pad.

[0020] In a possible implementation, the emitter molybdenum sheet has a corner, and the gate pad is adjacent to an area covered by the corner; and a probe of the temperature sensor is inserted into the area around the corner.

[0021] In a possible implementation, when the clamping force applied to the press-bonded IGBT chip is greater than a preset value, the temperature measured by the temperature sensor corresponds to the maximum temperature of the IGBT chip.

[0022] In a possible implementation, no additional temperature sensor is required in the emitter molybdenum sheet.

[0023] It can be understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0024] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0025] The present application provides a temperature measurement, packaging integrated device and method for a crimped IGBT chip. By installing a temperature sensor in the gap between the emitter molybdenum sheet and the chip gate pad, the maximum surface temperature of the IGBT chip can be directly monitored after the pressure of the crimped IGBT module is saturated; when the clamping force on the crimped IGBT device is large enough, the contact thermal resistance of the device decreases with the increase of the clamping force. As the clamping force increases, the double-sided heat dissipation effect is enhanced, so that the center temperature of the chip is reduced. The above gap cannot be well contacted and dissipated through the emitter molybdenum sheet, so the maximum surface temperature of the chip is concentrated in the above gap. This method does not require stopping the operation of the power converter, and the temperature monitoring of the crimped IGBT chip can be completed during the online operation of the power converter. The above method can avoid the influence of the mechanical pressure of the IGBT chip on the temperature sensor and ensure the accuracy of temperature measurement. In addition, this method does not require grooving the emitter molybdenum sheet and will not increase the thermal resistance of the crimped IGBT module. Furthermore, the above temperature sensor can be integrated with the crimped IGBT in an integrated package. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a crimped IGBT package structure including an uncovered area provided in an embodiment of the present application;

[0027] Figure 2 It is a front view schematic diagram of an IGBT chip with different heat dissipation methods provided in an embodiment of the present application;

[0028] Figure 3 It is a schematic diagram of the heat flow path of the press-fit IGBT with heat concentration and heat diffusion effects provided in an embodiment of the present application;

[0029] FIG4( a ) is a schematic diagram of the installation position of the temperature sensor at the center of the emitter molybdenum sheet provided in an embodiment of the present application;

[0030] FIG4( b ) is a schematic diagram of the installation position of the temperature sensor at the gap between the chip gate pad and the emitter molybdenum sheet provided in an embodiment of the present application;

[0031] FIG4( c ) is a schematic diagram of the installation position of the temperature sensor on the gate spring pin provided in an embodiment of the present application;

[0032] Figure 5 1 is a cross-sectional SEM image of an IGBT chip provided in an embodiment of the present application; (a) is the gate pad position, and (b) is the emitter pad position;

[0033] Figure 6 Schematic diagram of four heat generating areas on the surface of a chip provided in an embodiment of the present application;

[0034] Figure 7 It is a schematic diagram of a finite element electrothermal simulation model of a crimped IGBT provided in an embodiment of the present application;

[0035] Figure 8 Schematic diagram of the maximum temperature point displacement on the emitter surface of the crimped IGBT chip under different constant currents as the mechanical pressure increases, provided in an embodiment of the present application; (a) is 0.25 kN and 15 A, (b) is 2 kN and 25 A, and (c) is 5 kN and 35 A;

[0036] Fig. 9 Schematic diagram of the temperature distribution of the crimped IGBT of different package components at 0.25 kN and 15 A provided in the embodiment of the present application; (a) is the temperature of the crimped IGBT with the emitter molybdenum sheet grooved, and (b) is the temperature of the crimped IGBT with the gate spring pin holed;

[0037] Fig.10 This is a stress distribution diagram of the IGBT chip under 10kN crimping provided in the embodiment of the present application; (a) is the emitter molybdenum sheet with grooves, and (b) is the intact emitter molybdenum sheet;

[0038] Fig.11 10kN glue stress comparison diagram provided in the embodiment of the present application; (a) is the glue located in the narrow groove of the emitter molybdenum sheet, and (b) is the glue located at the gate spring pin head;

[0039] Fig.12 It is a schematic diagram of a crimped IGBT submodule assembly with three thermocouples provided in an embodiment of the present application;

[0040] Fig.13 Schematic diagram of a stereo microscope picture provided in an embodiment of the present application; (a) is a crimped IGBT chip with a thermocouple, (b) is an emitter molybdenum sheet with a thermocouple, and (c) is a gate spring pin with a thermocouple;

[0041] Fig.14 Schematic diagram of temperature measurement results of three thermocouples under different mechanical pressures provided in the embodiment of the present application; (a) is 0.25 kN, (b) is 2 kN, (c) is 5 kN, and (d) is 10 kN;

[0042] Fig.15 Schematic diagram of the maximum temperatures of three thermocouples under different mechanical pressures provided in the embodiments of the present application; (a) is 0.25 kN, (b) is 2 kN, (c) is 5 kN, and (d) is 10 kN;

[0043] Fig.16 This is a schematic diagram of heat dissipation and thermal coupling of a press-connected IGBT chip provided in an embodiment of the present application;

[0044] Fig.17 It is a schematic diagram of load current of a 5kN lower half-bridge inverter under different voltages provided in an embodiment of the present application;

[0045] Fig.18It is a schematic diagram of the temperature measurement results of a thermocouple installed in the gap between the emitter molybdenum sheet and the chip gate pad provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] The term "and / or" in this application is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this application indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0048] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0049] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0050] The present application proposes a method for integrated packaging and integration of a crimped IGBT chip and a temperature sensor, which specifically includes: a temperature measurement, packaging and integration device and method for crimped IGBT chips, a temperature sensor is installed in the gap between the emitter molybdenum sheet and the chip gate pad, and the maximum surface temperature of the IGBT chip can be directly monitored after the pressure of the crimped IGBT module is saturated. A hole is opened in the gate spring needle head, and the temperature sensor is installed in the hole to avoid the influence of mechanical pressure on the temperature sensor. The existing method is to make a groove in the center of the emitter molybdenum sheet and install the temperature sensor in the groove of the emitter molybdenum sheet. The present application selects three temperature sensor installation positions, and obtains the changes of three temperature measurement points under different mechanical pressures through a constant current test. The test verifies that after the mechanical pressure is saturated, the maximum surface temperature of the crimped IGBT chip is located at the gap between the emitter molybdenum sheet and the chip gate pad; therefore, the present application selects to install a temperature sensor in the gap between the emitter molybdenum sheet and the chip gate pad, and measures the maximum surface temperature of the crimped IGBT chip after the mechanical pressure is saturated. Then, through a half-bridge inverter test, it is verified that the installation of a temperature sensor in the gap can realize the online measurement of the IGBT chip temperature.

[0051] In a specific embodiment, Figure 1As shown, the structure of the crimped IGBT device may include, from top to bottom, a collector copper (Cu) plate, a collector molybdenum (Mo) sheet, an IGBT chip, an emitter molybdenum sheet, a silver gasket, an emitter copper boss, a gate spring pin, a gate printed circuit board (PCB), a polyetheretherketone (PEEK) plastic frame, and an emitter copper plate. It is understandable that the temperature measurement device provided in the present application is suitable for different types of crimped IGBT devices. Specifically, the crimped IGBT device may include: an IGBT chip, an emitter molybdenum sheet; in addition, other components are not limited to Figure 1 The structure shown may be other specific structures.

[0052] The IGBT chip contacts the corresponding copper electrode through the molybdenum sheet under the action of external clamping force, thereby achieving electrical connection and heat dissipation. The IGBT chip is sandwiched between the collector Mo sheet and the emitter Mo sheet. The area of ​​the collector Mo sheet is equal to the collector area of ​​the IGBT chip, and the collector area of ​​the IGBT chip is equal to the back area of ​​the IGBT chip. On the front of the IGBT chip, due to the presence of terminals and gate pads, the emitter molybdenum sheet area is smaller than the front area of ​​the IGBT chip. In order to ensure that the emitter molybdenum sheet does not contact the IGBT chip terminals and gate pads, the emitter molybdenum sheet area is also smaller than the emitter pad of the IGBT chip. The gate pad of the IGBT chip is connected to the gate PCB through a gate spring pin. The gate spring pin head is a smooth sphere, and the gate pad of the IGBT chip is a flat surface.

[0053] It should be noted that the IGBT chip consists of two parts: the active area (cell area) and the edge terminal area. The terminal area of ​​the high-voltage chip occupies a considerable part of the chip area. For example, for a 4500V chip with a size of 13.5mm×13.5mm, the terminal area occupies more than 40% of the total chip area. The terminal is used to improve the electric field distribution and prevent local high electric field breakdown.

[0054] The collector copper plate and collector molybdenum sheet act as good electrical and thermal conductors, realizing the current and heat flow path on the top of the IGBT chip. The entire back area of ​​the IGBT chip dissipates heat through the collector molybdenum sheet. The emitter molybdenum sheet, silver sheet, copper boss and emitter copper plate realize the current and heat flow path on the bottom of the IGBT chip. However, part of the emitter surface of the PP IGBT chip is covered by the emitter Mo sheet, and the rest is exposed to nitrogen. Figure 1 As shown, the area uncovered by the emitter molybdenum pad is marked. Due to the small size of the emitter molybdenum pad, the front area of ​​the IGBT chip that is not in contact with the emitter molybdenum pad cannot dissipate heat through the bottom layer. The contact area between the gate spring pin and the gate pad is too small to dissipate heat. In addition, since the front area of ​​the IGBT chip is larger than the area of ​​the emitter molybdenum pad, the emitter molybdenum gap will not directly diffuse heat downward through the emitter molybdenum pad.

[0055] According to the PP IGBT package structure, the entire back area of ​​the IGBT chip is cooled by the collector Mo and the collector Cu. However, due to the small emitter Mo sheet, some areas on the front side of the IGBT chip are not directly cooled by the emitter Mo. The front area covered by the emitter Mo sheet is directly cooled by the emitter Mo sheet. The remaining area not covered by the emitter Mo sheet may not be directly cooled by the metal with high thermal conductivity. Since the emitter Mo sheet area is smaller than the PP IGBT chip area, the uncovered area dissipates heat through lateral heat conduction. According to the heat dissipation method, the front area of ​​the IGBT chip is divided into two areas: the covered area and the uncovered area, such as Figure 2 shown.

[0056] like Figure 3 As shown, the PP IGBT chip as a heat source is cooled by the top cooling path and the bottom cooling path. When the chip heat is transferred to the heat sink, the low-temperature cooling water can dissipate the heat from the PP IGBT. The emitter molybdenum sheet area is smaller than the IGBT chip area. During the heat conduction from the IGBT chip to the emitter Mo, there is a thermal contraction effect. The thermal contraction effect refers to the situation where heat is transferred from a large area heat source to a small area heat sink. Due to the presence of a large area copper plate, there is heat diffusion, which is used to describe the situation where the heat source area is smaller than the heat sink area.

[0057] In the physical contact measurement method, the installation position of the temperature sensor greatly affects the temperature monitoring results of the IGBT chip due to the significant difference in the temperature distribution on the chip surface. Generally, for the soldered IGBT, the highest junction temperature is located at the center of the IGBT chip. All areas of the soldered IGBT chip are single-sided cooled, and the heat of the soldered IGBT chip is only transferred to the heat sink through the package component under the chip collector. Due to the influence of thermal coupling, the center temperature of the soldered IGBT chip is the highest. Therefore, the first installation position of the temperature sensor is located at the center of the emitter Mo pad near the PP IGBT chip, that is, Figure 3 Medium T j,cov The schematic diagram is used to monitor the center temperature of the PP IGBT chip. As shown in Figure 4(a), the large-sized emitter molybdenum sheet is also convenient for installing the temperature sensor.

[0058] The terminal area of ​​the chip is not the main heat generating area, so the installation position does not consider the terminal area. There is a cell structure under the gate pad, which is similar to the cell structure under the emitter pad, such as Figure 5 As shown in (a) and (b) in Figure 1, heat is also generated under the gate pad. The main heat generation area is divided into four areas, such as Figure 6As shown by the white dotted line in the middle. Due to the existence of the gate pad, the emitter Mo sheet has a gap near the gate pad to prevent the gate electrode and the emitter electrode from short-circuiting. Therefore, the uncovered area of ​​the emitter Mo sheet in area 1 is the largest, which may cause the maximum temperature point to move from the center of the PP IGBT chip to the gate pad, as shown in Figure 6 Therefore, the second mounting position of the temperature sensor is located in the gap between the chip gate pad and the emitter molybdenum pad, that is, Figure 3 Medium T j,uncov Schematic location; further preferably, the temperature at the corner of the emitter molybdenum sheet is usually the highest, so the probe of the temperature sensor extends into the vicinity of the corner covering the emitter molybdenum sheet; further referring to FIG4(b), the gap has two locations, horizontal and vertical, and the temperature sensor can be set at any gap, and its probe can extend to the corner position, as shown in FIG4(b). Installing the temperature sensor at the gap will not damage the packaging component of the PP IGBT.

[0059] Due to the clamping force, some locations of the package component are subject to mechanical stress, which may cause damage to the temperature sensor or inaccurate monitoring results. The gate spring pin with an internal spring can absorb the force to avoid damage to the temperature sensor. Therefore, the third mounting position is the gate spring pin near the PP IGBT chip, as shown in Figure 4(c).

[0060] Furthermore, since the collector side of the back of the IGBT chip has a high potential, the insulation requirements on the back are relatively high. Therefore, those skilled in the art usually measure the temperature of the crimped IGBT chip on the front side, and do not consider measuring the temperature on the back side. That is, generally, the collector potential of the IGBT chip is very high, and the collector surface is not suitable as the mounting plane of the temperature sensor. Due to the risk of high-voltage breakdown, the mounting position of the collector side of the PP IGBT is not considered.

[0061] In order to study the temperature monitoring results at the three installation locations, a finite element electrothermal model was established, such as Figure 7 The material parameters and dimensions of the components are shown in Table 1. Ф is the diameter. S a It is the active area of ​​the IGBT chip. CA is the abbreviation of cyanoacrylate. The boundary conditions are set as follows. The emitter Cu potential is set to 0V. A constant current is applied to the surface of the collector Cu, and double-sided heat dissipation is adopted. The convection heat transfer coefficient of the collector Cu and emitter Cu surfaces is set to 0.02W / (mm 2 ·K). The emitter Cu surface is set as a fixed support. The clamping force is applied to the collector Cu surface, such as Figure 7 In order to simulate the effect of clamping force on the temperature distribution of PP IGBT, different thermal contact resistances are set.

[0062] Table 1 Material parameters and dimensions of crimped IGBT in finite element model

[0063]

[0064]

[0065] As the clamping force increases, the highest temperature point on the surface of the PP IGBT emitter chip will drift, such as Figure 8 As shown. In order to increase the difference between the center temperature and the gap temperature, different constant currents are applied under different clamping forces. When the clamping force is 0.25kN, the highest temperature point is located at the center of the emitter surface of the PP IGBT chip. Due to the large contact thermal resistance of 0.25kN, the vertical heat dissipation is small, and the double-sided heat dissipation effect is not obvious. Under the effect of lateral thermal coupling, the highest temperature point is located at the center of the PP IGBT chip, as shown Figure 8 As shown in (a) in the figure, as the clamping force increases to 2 kN, the gap temperature between the chip gate pad and the emitter molybdenum sheet gradually approaches the center temperature of the PP IGBT chip, as shown in Figure 8 As shown in (b), this is the result of the increased double-sided heat dissipation effect after increasing the clamping force. When the clamping force is increased to 5kN, the highest temperature point moves from the center of the PP IGBT chip to the edge, as shown in Figure 8 As shown in (c). In addition, at 5kN, the highest temperature point of the PP IGBT chip is not covered by the emitter Mo pad. At 5kN, the double-sided heat dissipation effect exceeds the thermal coupling effect.

[0066] like Fig. 9 As shown, the present application established an emitter molybdenum sheet model with a narrow groove and a gate spring pin model with a hole on the head to study the effect of processed packaging components on the PP IGBT chip temperature. Fig. 9 The temperature distribution results of the PP IGBT chip are Figure 8 Compare the results of (a) in Figure 2. Fig. 9 As shown in (a), the maximum temperature of the pressed IGBT chip under the emitter molybdenum sheet with narrow grooves is 2.136℃ higher than the maximum temperature under the complete emitter molybdenum sheet. Fig. 9 As shown in (b), due to the small contact area of ​​the gate spring pin, the hole in the spring pin head has little effect on the thermal resistance of the crimped IGBT module. The narrow groove is filled with an adhesive with low thermal conductivity. Since the emitter molybdenum sheet is the main vertical heat dissipation path of the PP IGBT, the temperature of the PP IGBT chip increases more under the emitter molybdenum with narrow grooves. Therefore, combined with the above analysis, it can be seen that the groove of the emitter molybdenum sheet will cause the temperature of the PP IGBT chip to increase; the hole in the spring pin head will basically not cause the chip temperature to increase.

[0067] The electrical connection and heat conduction of PP IGBT need to be completed by clamping force. The stress distribution of PP IGBT chip under different emitter molybdenum sheets is as follows: Fig.10 As shown. Fig.10 As shown in (a) and (b), under the emitter molybdenum sheet with narrow grooves, the stress distribution of the PP IGBT chip is more uneven, and the maximum stress increases from 594.33MPa to 817.43MPa.

[0068] Usually, in order to measure the PP IGBT chip temperature, the temperature sensor is adhered to the mounting location by adhesive. When the temperature sensor is also affected by stress, the temperature measurement result of the sensor will be affected by the adhesive stress. Fig.11 As shown in (a) and (b), the stress of the adhesive under 10kN is studied. The stress of the adhesive at the narrow groove of the emitter molybdenum gasket is about 1500 times that of the adhesive at the gate spring needle hole, and the temperature sensor installed at the gate spring needle hole is less affected by the stress.

[0069] It is understandable that the temperature sensor mentioned in the embodiments of the present application can be implemented by a thermocouple, and those skilled in the art can select other types of temperature sensors according to needs and actual conditions, and the present application does not make any further limitations on this. The following embodiments are illustrated by taking a thermocouple as an example.

[0070] In order to verify the practicality of the PP IGBT temperature monitoring sensor integration solution, a PP IGBT chip self-heating platform under a constant current source was built. The self-heating platform includes a half-bridge inverter. The components of the PP IGBT submodule with three thermocouples are as follows: Fig.12 The IGBT chip, emitter molybdenum sheet and gate spring pin with thermocouple were observed through a stereo microscope. Fig.13 For the specific installation dimensions of the thermocouple, see Fig.13 , three temperature sensors monitor the temperature of three locations on the chip surface simultaneously. The measurement cycle of the thermocouple is 1 second.

[0071] The experimental scheme under constant current conditions is as follows. First, a clamping force is applied to the PP IGBT. The clamping force applied is 0.25kN, 2kN, 5kN and 10kN respectively. The magnitude of the applied clamping force is displayed by the force sensor. The test starts after the PP IGBT is clamped. After the PP IGBT is turned on, a constant DC current is applied to heat the IGBT chip. The heating time is set to 8 minutes. After the heating time is over, the PP IGBT is turned off and cooled. The cooling time is set to 5 minutes. After one cycle is over, the constant current is increased and the next cycle begins. A total of four cycles are performed under a specific clamping force, and the temperature range covers the range of the PP IGBT junction temperature.

[0072] The experimental scheme under the half-bridge inverter condition is as follows. The 5kN PP IGBT half-bridge module is operated at DC bus voltages of 100V, 200V, 300V, 400V, and 500V. The PWM signal is sent by the DSP TMS320F28335 to generate a sinusoidal signal with a frequency of 50Hz. The PP IGBT half-bridge module is operated for 3 minutes at each DC bus voltage. There is a cooling time interval between each voltage. The cooling time interval is set to 3 minutes.

[0073] like Fig.14 As shown in Figure 1, the temperature measurements of three thermocouples at 0.25 kN, 2 kN, 5 kN and 10 kN were recorded with a period of 1 second. The PP IGBT is heated after the constant DC current is turned on and cooled after the current is turned off. Fig.15 As shown in Figure 1, the maximum temperature of the three thermocouples at each current before the PP IGBT turns off is recorded. In order to make the PP IGBT self-heating, the constant DC current applied to the PP IGBT is 10A, 15A, 20A and 23A at 0.25kN, as shown in Figure 1. Fig.14 As shown in (a). Under each constant DC, the temperature measurement result of the thermocouple located at the emitter molybdenum pad is the highest. As the constant DC increases, the difference between the three thermocouples increases as shown in Fig.15 As shown in (a).

[0074] However, if Fig.14 (b) and Fig.15 As shown in (b), the temperature of the thermocouple located at the gap between the chip gate pad and the emitter molybdenum sheet is equal to the temperature of the thermocouple located at the center of the emitter molybdenum uniform field when 2kN. Fig.14 Middle (c), Fig.14 Middle (d), Fig.15 (c) and Fig.15 As shown in (d), when the clamping force increases to 5kN and 10kN, the temperature of the thermocouple located at the gap between the chip gate pad and the emitter molybdenum sheet is higher than the temperature of the thermocouple located at the center of the emitter molybdenum sheet. At 10kN, the temperature of the thermocouple located at the gate spring pin is close to the temperature of the thermocouple located at the center of the emitter molybdenum sheet, as shown in Figure 1. Fig.14 Middle (d) and Fig.15 As shown in (d), as the clamping force increases, the drift of the highest temperature point is consistent with the simulation results.

[0075] Lateral thermal coupling and vertical heat dissipation of press-fit IGBTs Fig.16As shown. For the installation positions of the two temperature sensors, the collector side contact thermal resistance is the same. The lateral thermal coupling is not affected by the clamping force, and the chip surface temperature distribution is mainly affected by the emitter side contact thermal resistance. Under 0.25kN, the lateral thermal coupling effect within the IGBT chip is greater than the vertical double-sided heat dissipation effect, which makes the center temperature the highest. The contact thermal resistance decreases with the increase of the clamping force. As the clamping force increases, the vertical double-sided heat dissipation effect is enhanced, which reduces the center temperature of the chip.

[0076] In order to verify the feasibility of online monitoring of chip temperature by the thermocouple located between the chip gate pad and the emitter molybdenum sheet, the half-bridge inverter is operated at bus voltages of 100V, 200V, 300V, 400V and 500V. Fig.17 The measurement results of the thermocouple located between the chip gate pad and the emitter molybdenum sheet were recorded, as shown in Fig.18 To prevent the thermal runaway failure of the PP IGBT, the bus voltage will not increase further.

[0077] Further preferably, the above-mentioned temperature measuring device, the press-fit IGBT device including the temperature measuring device, and the device integrated and packaged together with the press-fit IGBT device, should all fall within the protection scope of the embodiments of the present application, and no further elaboration is given for this.

[0078] In summary, in the embodiment of the present application, by measuring and comparing the temperature at three different positions of the crimped IGBT chip, it is proved that the maximum temperature of the IGBT chip can be measured at the above-mentioned gap, so the present application provides the above-mentioned temperature measurement device. Based on this, the temperature measurement device provided by the present application realizes online monitoring of the temperature of the crimped IGBT chip through a physical contact method without interfering with the normal operation of the power converter. The integrated packaging integration technology of the crimped IGBT chip and the temperature sensor provided by the present application can measure the maximum surface temperature of the crimped IGBT chip. The above-mentioned temperature measurement method can be unaffected by mechanical stress, will not damage the temperature sensor, and ensures the stable operation of the temperature sensor.

[0079] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0080] In addition, in the present application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0081] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0082] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0083] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A temperature measurement device for a crimped IGBT chip, the crimped IGBT device comprising: An IGBT chip and an emitter molybdenum sheet, wherein the IGBT chip comprises a gate pad and an emitter pad, the gate pad and the emitter pad are located on the front of the chip, and the emitter molybdenum sheet is bonded to the emitter pad; the measuring device comprises a temperature sensor; The temperature sensor, when arranged in the gap between the gate pad and a preset area on the front side of the IGBT chip, is used to measure the temperature of the IGBT chip; the preset area is the area on the front side of the IGBT chip covered by the emitter molybdenum sheet, and the preset area is adjacent to the gate pad.

2. The device according to claim 1, characterized in that The emitter molybdenum sheet has a corner, and the gate pad is adjacent to the area covered by the corner; when the temperature sensor is used to measure the temperature of the IGBT chip, its probe penetrates into the area around the corner coverage.

3. The device according to claim 1 or 2, characterized in that: When the clamping force applied to the press-bonded IGBT chip is greater than a preset value, the temperature measured by the temperature sensor corresponds to the maximum temperature of the IGBT chip.

4. The device according to claim 1 or 2, characterized in that: No additional temperature sensor is required in the emitter molybdenum sheet.

5. A crimped IGBT chip, characterized in that: The temperature measuring device comprises the temperature measuring device according to any one of claims 1 to 4, wherein the temperature sensor is arranged at the gap.

6. A packaging and integration device for crimping an IGBT chip, characterized in that: include: A crimped IGBT device and a temperature measuring device as claimed in any one of claims 1 to 4; The temperature sensor is arranged at the gap, and the temperature sensor is synchronously packaged and integrated with the press-fit IGBT device.

7. A method for measuring the temperature of a crimped IGBT chip, the crimped IGBT device comprising: An IGBT chip and an emitter molybdenum sheet, wherein the IGBT chip comprises a gate pad and an emitter pad, wherein the gate pad and the emitter pad are located on the front side of the chip, and the emitter molybdenum sheet is bonded to the emitter pad; the method comprises: A temperature sensor is arranged in the gap between the gate pad and a preset area on the front side of the IGBT chip to measure the temperature of the IGBT chip; the preset area is the area on the front side of the IGBT chip covered by the emitter molybdenum sheet, and the preset area is adjacent to the gate pad.

8. The method according to claim 7, characterized in that The emitter molybdenum sheet has a corner, and the gate pad is adjacent to the area covered by the corner; the probe of the temperature sensor is inserted into the area around the corner.

9. The method according to claim 7 or 8, characterized in that: When the clamping force applied to the press-bonded IGBT chip is greater than a preset value, the temperature measured by the temperature sensor corresponds to the maximum temperature of the IGBT chip.

10. The method according to claim 7 or 8, characterized in that: No additional temperature sensor is required in the emitter molybdenum sheet.

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