Temperature measurement, packaging integrated device and method for press-pack igbt chip

Abstract

The application belongs to the field of chip and chip integrated packaging, and specifically discloses a temperature measurement and packaging integrated device and method for crimping IGBT chips. The temperature measurement device is applied to a crimping IGBT device, which comprises an IGBT chip and an emitter molybdenum sheet. The IGBT chip comprises a gate pad and an emitter pad, and the gate pad and the emitter pad are located on the front surface of the chip. The emitter molybdenum sheet is attached to the emitter pad. The measurement device comprises a temperature sensor. When the temperature sensor is arranged in the gap between the gate pad on the front surface of the IGBT chip and a preset area, the temperature sensor is used for measuring the temperature of the IGBT chip. The preset area is the area on the front surface of the IGBT chip covered by the emitter molybdenum sheet. According to the application, the temperature sensor is installed at the gap between the emitter molybdenum sheet and the gate pad of the chip, so that 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] This application belongs to the field of chips and chip integrated packaging, and more specifically, relates to a temperature measurement, packaging integration device and method for a press-fit insulated-gate bipolar transistor (IGBT) chip. Background Technology

[0002] Press-fit 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 soldered IGBTs, PP IGBTs offer advantages such as high power density, double-sided cooling, low parasitic inductance, ease of series connection, and fault short-circuit protection. As the most vulnerable component in power conversion systems, the reliability of PP IGBTs has attracted widespread attention. Among various failure factors in power semiconductors, overheating failure accounts for the highest proportion. Online monitoring of PP IGBT junction temperature helps extend device life and improve the formulation of maintenance strategies for flexible DC transmission systems. Existing junction temperature monitoring methods can be categorized into: physical contact measurement methods, optical non-contact measurement methods, thermal impedance model prediction methods, and temperature-sensitive electrical parameter (TSEP) methods.

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

[0004] Furthermore, existing literature 1, "Quasi-Distributed Temperature Detection of Press-Pack IGBT Power Module Using FBG Sensing," proposes inserting an optical fiber into the molybdenum sheet of the elastically press-fitted IGBT to extract the chip temperature. However, this location is subject to stress, causing the optical Bragg grating temperature measurement to be affected by pressure. This method must eliminate the influence of pressure on the optical fiber monitoring results. Existing literature 2, "Experimental Verification of the Junction Temperature Distribution within Press Pack IGBTs," proposes slotting the emitter molybdenum sheet of the press-fitted IGBT and inserting a thermocouple. However, filling the slotted emitter molybdenum sheet with glue increases the thermal resistance of the press-fitted IGBT module, increasing the chip operating temperature. Existing literature 3, "Thermal Contact Resistance Optimization of Press-Pack IGBT Device Based on Liquid Metal Thermal Interface Material," proposes inserting a thermocouple at the edge of the press-fitted IGBT submodule. However, this location is at the chip terminal edge, which is not part of the active region and has a lower temperature, far below the chip's maximum temperature.

[0005] In summary, existing physical contact measurement methods cannot accurately measure the maximum temperature of the press-fit IGBT chip. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide a temperature measurement, packaging and integration device and method for press-fit IGBT chips, which aims to solve the problem that the existing physical contact measurement method cannot accurately measure the maximum temperature of press-fit IGBT chips.

[0007] To achieve the above objectives, in a first aspect, this application provides a temperature measurement device for a press-fit IGBT chip. The press-fit IGBT device includes: an IGBT chip and an emitter molybdenum sheet. The IGBT chip includes: a gate pad and an emitter pad, the gate pad and the emitter pad being located on the front side of the chip, and the emitter molybdenum sheet being attached to the emitter pad. The measurement device includes: a temperature sensor.

[0008] The temperature sensor, when positioned 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 press-fit IGBT devices typically operate under pressure saturation. Following conventional thinking in the field, due to thermal coupling effects, the maximum temperature of such devices is usually located at the device center. Therefore, existing physical contact measurement methods typically involve slotting a temperature sensor at the center of the emitter molybdenum sheet. However, research has shown that the measured temperature is not the maximum temperature, and slotting the emitter molybdenum sheet increases the chip's operating temperature. This application's research reveals that the maximum temperature of the IGBT chip under pressure saturation occurs in the gap between the gate pad and the area covered by the emitter molybdenum sheet. Therefore, placing a temperature sensor directly at this location eliminates the need for slotting the emitter molybdenum sheet, avoids introducing additional temperature rise, and allows for direct and relatively accurate temperature measurement, precisely reflecting the maximum temperature of the press-fit IGBT chip.

[0010] In one possible implementation, 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 extends into the area around the corner.

[0011] Typically, when a press-fit IGBT device operates under pressure saturation, the temperature of the IGBT chip at the aforementioned corner is the highest.

[0012] In one possible implementation, when the clamping force on the pressed 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 can be the clamping force required for pressure saturation of the crimped IGBT device. Pressure saturation refers to the clamping force exceeding a certain critical mechanical pressure. Typically, crimped IGBT devices need to operate under pressure saturation conditions.

[0014] In one possible implementation, no additional temperature sensor is required in the emitter molybdenum sheet.

[0015] Secondly, this application provides a press-fit IGBT chip, including the temperature measuring device described in the first aspect or any possible implementation of the first aspect, wherein the temperature sensor is disposed at the gap.

[0016] Thirdly, this application provides a packaged integration device for press-fit IGBT chips, including: a press-fit IGBT device and a temperature measuring device as described in the first aspect or any possible implementation of the first aspect.

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

[0018] Fourthly, this application provides a temperature measurement method for a press-fit IGBT chip. The press-fit IGBT device includes an IGBT chip and an emitter molybdenum sheet. The IGBT chip includes a gate pad and an emitter pad, which are located on the front side of the chip. The emitter molybdenum sheet is attached to the emitter pad. The method includes:

[0019] A temperature sensor is placed 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 one possible implementation, 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.

[0021] In one possible implementation, when the clamping force on the pressed 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 one possible implementation, no additional temperature sensor is required in the emitter molybdenum sheet.

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

[0024] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0025] This application provides a temperature measurement and packaging integration device and method for press-fit IGBT chips. 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 press-fit IGBT module is pressure saturated. When the clamping force on the press-fit IGBT device is large enough, the contact thermal resistance of the device decreases with the increase of clamping force. As the clamping force increases, the double-sided heat dissipation effect is enhanced, reducing the center temperature of the chip. Since the gap cannot achieve good contact heat dissipation through the emitter molybdenum sheet, the maximum surface temperature of the chip is concentrated in the gap. This method does not require stopping the power converter; the temperature monitoring of the press-fit IGBT chip can be completed during the online operation of the power converter. This method avoids the influence of the mechanical pressure of the IGBT chip on the temperature sensor, ensuring the accuracy of temperature measurement. Furthermore, this method does not require slotting the emitter molybdenum sheet, thus not increasing the thermal resistance of the press-fit IGBT module. Moreover, the temperature sensor can be integrated into a single press-fit IGBT package. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a press-fit IGBT package structure including uncovered areas provided in an embodiment of this application;

[0027] Figure 2 This is a front view of an IGBT chip with different heat dissipation methods provided in the embodiments of this application;

[0028] Figure 3 This is a schematic diagram of the heat flow path of a press-fitted IGBT with heat concentration and heat diffusion effects provided in the embodiments of this application;

[0029] Figure 4(a) is a schematic diagram of the installation position of the temperature sensor at the center of the emitter molybdenum plate provided in the embodiment of this application;

[0030] Figure 4(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 the embodiment of this application;

[0031] Figure 4(c) is a schematic diagram of the installation position of the temperature sensor on the gate spring pin provided in the embodiment of this application;

[0032] Figure 5 These are cross-sectional SEM images of the IGBT chip provided in the embodiments of this application; (a) shows the location of the gate pad, and (b) shows the location of the emitter pad.

[0033] Figure 6 This is a schematic diagram of four heat-generating areas on the chip surface provided in an embodiment of this application;

[0034] Figure 7 This is a schematic diagram of the finite element electrothermal simulation model of the press-fit IGBT provided in the embodiments of this application;

[0035] Figure 8 This is a schematic diagram showing the shift of the maximum temperature point on the emitter surface of the IGBT chip under different constant currents as mechanical pressure increases, provided in the embodiments of this application; (a) is 0.25kN and 15A, (b) is 2kN and 25A, and (c) is 5kN and 35A.

[0036] Figure 9 This is a schematic diagram of the temperature distribution of press-fit IGBTs with different package components at 0.25kN and 15A provided in the embodiments of this application; (a) is the temperature of press-fit IGBTs with slotted emitter molybdenum sheet, and (b) is the temperature of press-fit IGBTs with open gate spring pin.

[0037] Figure 10 This is a stress distribution diagram of a 10kN pressure-connected IGBT chip provided in the embodiments of this application; (a) shows the slotted emitter molybdenum sheet, and (b) shows the intact emitter molybdenum sheet;

[0038] Figure 11 This is a comparison diagram of adhesive stress at 10kN provided in the embodiments of this application; (a) is the adhesive located in the narrow groove of the emitter molybdenum sheet, and (b) is the adhesive located at the head of the gate spring pin;

[0039] Figure 12 This is a schematic diagram of a crimped IGBT submodule assembly with three thermocouples provided in an embodiment of this application;

[0040] Figure 13 These are schematic diagrams of stereomicroscope images provided in the embodiments of this application; (a) is a press-fit 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] Figure 14 This is a schematic diagram of the temperature measurement results of three thermocouples under different mechanical pressures provided in the embodiments of this application; (a) is 0.25kN, (b) is 2kN, (c) is 5kN, and (d) is 10kN.

[0042] Figure 15 This is a schematic diagram of the maximum temperature of three thermocouples under different mechanical pressures provided in the embodiments of this application; (a) is 0.25kN, (b) is 2kN, (c) is 5kN, and (d) is 10kN.

[0043] Figure 16 This is a schematic diagram of the heat dissipation and thermal coupling of the press-fit IGBT chip provided in the embodiments of this application;

[0044] Figure 17 This is a schematic diagram of the load current of the 5kN lower half-bridge inverter under different voltages provided in the embodiments of this application;

[0045] Figure 18This is a schematic diagram of the temperature measurement results of a thermocouple installed at the gap between the emitter molybdenum sheet and the chip gate pad, provided in an embodiment of this application. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0047] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. In this application, the symbol " / " indicates that the related objects are in an "or" relationship, for example, A / B means A or B.

[0048] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0049] The embodiments of this application are described below with reference to the accompanying drawings.

[0050] This application proposes an integrated packaging method for a press-fit IGBT chip and a temperature sensor. Specifically, it includes a temperature measurement device and method for the press-fit IGBT chip. A temperature sensor is installed in the gap between the emitter molybdenum sheet and the chip gate pad, allowing direct monitoring of the maximum surface temperature of the IGBT chip after the press-fit IGBT module has reached pressure saturation. An opening is made in the head of the gate spring pin, and the temperature sensor is installed in this opening to avoid the influence of mechanical pressure on the temperature sensor. Existing methods involve creating a groove in the center of the emitter molybdenum sheet and installing the temperature sensor within the groove. This application selects three temperature sensor installation locations and obtains the temperature variation at three measurement points under different mechanical pressures through constant current experiments. The experiments verify that after mechanical pressure saturation, the maximum surface temperature of the press-fit IGBT chip is located at the gap between the emitter molybdenum sheet and the chip gate pad. Therefore, this application selects the gap between the emitter molybdenum sheet and the chip gate pad to install the temperature sensor and measure the maximum surface temperature of the press-fit IGBT chip after mechanical pressure saturation. Subsequently, a half-bridge inverter experiment verifies that installing the temperature sensor at this gap enables online measurement of the IGBT chip temperature.

[0051] In a specific embodiment, such as Figure 1As shown, the structure of a press-fit IGBT device, from top to bottom, includes a collector copper (Cu) plate, a collector molybdenum (Mo) sheet, an IGBT chip, an emitter molybdenum sheet, a silver pad, 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 understood that the temperature measuring device provided in this application is applicable to different types of press-fit IGBT devices. Specifically, a press-fit IGBT device may include: an IGBT chip and an emitter molybdenum sheet; other components are not limited to these. Figure 1 The structure shown can be any other specific structure.

[0052] Under external clamping force, the IGBT chip contacts the corresponding copper electrode via a molybdenum sheet, thus achieving electrical connection and heat dissipation. The IGBT chip is clamped between a collector molybdenum sheet and an emitter molybdenum sheet. The area of ​​the collector molybdenum sheet is equal to the collector area of ​​the IGBT chip, while the collector area of ​​the IGBT chip is equal to the back surface area of ​​the IGBT chip. On the front side of the IGBT chip, due to the presence of termination and gate pads, the emitter molybdenum sheet area is smaller than the front surface area of ​​the IGBT chip. To ensure that the emitter molybdenum sheet does not contact the IGBT chip termination and gate pads, the emitter molybdenum sheet area is also smaller than the IGBT chip emitter pads. The gate pads of the IGBT chip are connected to the gate PCB via gate spring pins. The head of the gate spring pin is a smooth sphere, while the gate pads of the IGBT chip are flat surfaces.

[0053] It should be noted that an IGBT chip consists of two parts: the active region (cell region) and the edge termination region. The termination region of a high-voltage chip occupies a significant portion of the chip area. For example, in a 4500V chip with dimensions of 13.5mm × 13.5mm, the termination area accounts for more than 40% of the total chip area. The termination is used to improve the electric field distribution and prevent breakdown caused by localized high electric fields.

[0054] The collector copper plate and collector molybdenum sheet, acting as excellent electrical and thermal conductors, provide the top-layer current and heat flow path for the IGBT chip. The entire back surface of the IGBT chip is cooled by the collector molybdenum sheet. The emitter molybdenum sheet, silver sheet, copper bumps, and emitter copper plate provide the bottom-layer current and heat flow path for the IGBT chip. However, a portion of the emitter surface of the PP IGBT chip is covered by the emitter molybdenum sheet, while the remainder is exposed to nitrogen gas. Figure 1 As shown, the area not covered 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 underlying layer. The contact area between the gate spring pin and the gate pad is too small to dissipate heat. Furthermore, because the front area of ​​the IGBT chip is larger than the area of ​​the emitter molybdenum pad, the emitter molybdenum gap does not allow for direct downward heat diffusion through the emitter molybdenum pad.

[0055] According to the PP IGBT packaging structure, the entire back surface of the IGBT chip is cooled by the collector (Mo) and collector (Cu). However, due to the small size of the emitter (Mo) sheet, some areas on the front surface of the IGBT chip are not directly cooled by the emitter (Mo). The front surface area covered by the emitter (Mo) sheet dissipates heat directly through the emitter (Mo). The remaining area not covered by the emitter (Mo) sheet may not dissipate heat directly through the highly thermally conductive metal. Because the area of ​​the emitter (Mo) sheet is smaller than that of the PP IGBT chip, the uncovered area dissipates heat through lateral thermal conduction. Based on the heat dissipation method, the front surface of the IGBT chip is divided into two areas: the covered area and the uncovered area, such as... Figure 2 As shown.

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

[0057] In physical contact measurement methods, the installation location of the temperature sensor significantly affects the temperature monitoring results of the IGBT chip due to the significant differences in temperature distribution on the chip surface. Typically, for soldered IGBTs, the highest junction temperature is located at the center of the IGBT chip. All areas of the soldered IGBT chip are cooled on one side, and the heat from the soldered IGBT chip is transferred to the heat sink only through the packaging components below the chip collector. Due to thermal coupling, the center temperature of the soldered IGBT chip is the highest. Therefore, the first installation location for the temperature sensor is located at the center of the emitter Mo pad near the PP IGBT chip, i.e. Figure 3 China T j,cov The large emitter molybdenum sheet is used to monitor the center temperature of the PP IGBT chip, as shown in Figure 4(a). It also facilitates the installation of a temperature sensor.

[0058] The chip termination area is not a primary heat-generating area, and its installation location is not considered in relation to the termination area. Below the gate pad is a cell structure similar to the cell structure below the emitter pad, such as... Figure 5 As shown in (a) and (b) in the image, heat is also generated below the gate pad. The main heat-generating areas are divided into four regions, as follows: Figure 6As shown by the white dashed line. Due to the presence of the gate pad, the emitter molybdenum sheet has a gap near the gate pad to prevent short circuits between the gate and emitter electrodes. Therefore, the uncovered area of ​​the emitter molybdenum sheet is largest in region 1, which may cause the maximum temperature point to shift from the center of the PP IGBT chip to the gate pad, as shown by... Figure 6 As shown by the red dashed line. Therefore, the second mounting location for the temperature sensor is located in the gap between the chip gate pad and the emitter molybdenum pad, i.e. Figure 3 China T j,uncov As shown in the diagram; more preferably, the temperature is usually highest at the corner of the emitter molybdenum sheet, therefore the probe of the temperature sensor extends into the vicinity of the corner covered by the emitter molybdenum sheet; further referring to Figure 4(b), the gap has both lateral and longitudinal locations, and the temperature sensor can be placed at either gap, with its probe extending towards the corner position, as shown in Figure 4(b). Installing the temperature sensor at the gap will not damage the PP IGBT packaging assembly.

[0059] Due to the clamping force, certain locations on the packaged assembly are subject to mechanical stress, which may damage the temperature sensor or result in inaccurate readings. Gate spring pins with internal springs can absorb this force, thus preventing damage to the temperature sensor. Therefore, a third mounting location is the gate spring pin near the PP IGBT chip, as shown in Figure 4(c).

[0060] Furthermore, because the collector side of the IGBT chip has a high potential, its back side requires high insulation. Therefore, those skilled in the art typically perform temperature measurements on the front side of the IGBT chip during pressing, and do not consider measuring the temperature on the back side. In general, the collector potential of an IGBT chip is very high, and the collector surface is not suitable as a mounting plane for a temperature sensor. Due to the risk of high-voltage breakdown, the mounting position on the collector side of the PP IGBT is not considered.

[0061] To study the temperature monitoring results at the three installation locations, a finite element electrothermal model was established, such as... Figure 7 As shown, the material parameters and dimensions of the components are listed in Table 1. Ф represents the diameter. S a This is the active region of the IGBT chip. CA is an abbreviation for cyanoacrylate. The boundary conditions are set as follows: the emitter Cu potential is set to 0V. A constant current is applied to the upper surface of the collector Cu, using double-sided heat dissipation. The convective heat transfer coefficient between the collector Cu and emitter Cu surfaces is set to 0.02 W / (mm²). 2 • K). The emitter Cu surface is configured as a fixed support. Clamping force is applied to the current collector Cu surface, such as Figure 7 As shown. To simulate the effect of clamping force on the temperature distribution of PP IGBTs, different thermal contact resistances were set.

[0062] Table 1. Material parameters and dimensions of the press-fit IGBT in the 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. To increase the temperature difference between the center and the gap, different constant currents were applied under different clamping forces. When the clamping force was 0.25 kN, the highest temperature point was located at the center of the emitter surface of the PP IGBT chip. Due to the relatively large contact thermal resistance of 0.25 kN, vertical heat dissipation was small, and the double-sided heat dissipation effect was not significant. Under the effect of lateral thermal coupling, the highest temperature point was located at the center of the PP IGBT chip, as shown. Figure 8 As shown in (a), as the clamping force increases to 2kN, the gap temperature between the chip gate pad and the emitter molybdenum sheet gradually approaches the center temperature of the PP IGBT chip, as... Figure 8 As shown in (b), this is the result of increased heat dissipation on both sides after increasing the clamping force. When the clamping force increases to 5kN, the highest temperature point shifts from the center of the PP IGBT chip towards the edge, as shown in (b). Figure 8 As shown in (c). Furthermore, 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 outweighs the thermal coupling effect.

[0066] like Figure 9 As shown, this application establishes an emitter molybdenum sheet model with a narrow slot and a gate spring pin model with a hole in the head to study the influence of the processed packaged components on the temperature of the PPIGBT chip. Figure 9 Temperature distribution results of PP IGBT chips and Figure 8 Compare the results in (a). Figure 9 As shown in (a), the highest temperature of the press-fit IGBT chip under the narrow-groove emitter molybdenum sheet is 2.136°C higher than the highest temperature under the intact emitter molybdenum sheet. Figure 9 As shown in (b), due to the small contact area of ​​the gate spring pin, the hole at the spring pin head has little impact on the thermal resistance of the IGBT module. The narrow slot is filled with an adhesive with low thermal conductivity. Since the emitter molybdenum sheet is the main vertical heat dissipation path for the PP IGBT, the PP IGBT chip temperature rises more under the narrow slot emitter molybdenum sheet. Therefore, based on the above analysis, it can be concluded that slotting the emitter molybdenum sheet will cause the PP IGBT chip temperature to rise; opening the hole at the spring pin head will basically not cause the chip temperature to rise.

[0067] Electrical connections and thermal conduction of PP IGBTs require clamping force. The stress distribution of PP IGBT chips under different emitter molybdenum sheets is as follows: Figure 10 As shown. Figure 10 As shown in (a) and (b), under the emitter molybdenum sheet with narrow groove, the stress distribution of the PP IGBT chip is more uneven, and the maximum stress increases from 594.33 MPa to 817.43 MPa.

[0068] Typically, to measure the temperature of a PP IGBT chip, a temperature sensor is adhered to the mounting location using adhesive. When the temperature sensor is also subject to stress, the temperature measurement results will be affected by the adhesive stress. Figure 11 As shown in (a) and (b), the stress of the adhesive at 10 kN was investigated. The stress of the adhesive located at the narrow groove of the emitter molybdenum pad is approximately 1500 times that at the gate spring needle hole, while the temperature sensor mounted at the gate spring needle hole is less affected by the stress.

[0069] It is understood that the temperature sensor mentioned in the embodiments of this application can be implemented using a thermocouple. Those skilled in the art can select other types of temperature sensors according to their needs and actual circumstances, and this application does not impose any further limitations on this. The following embodiments use a thermocouple as an example for illustration.

[0070] To verify the practicality of the PPIGBT temperature monitoring sensor integration solution, a self-heating platform for the PPIGBT chip under a constant current source was built. This self-heating platform includes a half-bridge inverter. The components of the PPIGBT submodule with three thermocouples are as follows: Figure 12 As shown. The IGBT chip, emitter molybdenum plate, and gate spring pin with thermocouple were observed using a stereomicroscope, as shown. Figure 13 As shown. See also the specific installation dimensions for the thermocouple. Figure 13 Three temperature sensors simultaneously monitor the temperature at three locations on the chip surface. The thermocouple measurement cycle is 1 second.

[0071] The experimental procedure under constant current conditions is as follows: First, clamping forces of 0.25 kN, 2 kN, 5 kN, and 10 kN are applied to the PP IGBT. The magnitude of the clamping force is displayed by a force sensor. After the PP IGBT is clamped, the test begins. Once 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, the PP IGBT is turned off and cooled. The cooling time is set to 5 minutes. After one cycle, the constant current is increased, and the next cycle begins. Four cycles are performed under specific clamping forces, covering the temperature range of the PP IGBT junction temperature.

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

[0073] like Figure 14 As shown, 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 a constant DC current is applied and cooled after the current is turned off. Figure 15 As shown, the highest temperatures of the thermocouples at each current were recorded for the three thermocouples before the PPIGBT turn-off current. To enable the PPIGBT to self-heat, constant DC currents of 10A, 15A, 20A, and 23A were applied to the PPIGBT at a current of 0.25kN. Figure 14 As shown in (a), the temperature measurement of the thermocouple located at the emitter molybdenum pad is the highest under each constant DC current. The difference between the three thermocouples increases with increasing constant DC current. Figure 15 As shown in (a).

[0074] However, as Figure 14 (b) and Figure 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 the temperature is 2 kN. Figure 14 (c) Figure 14 (d) Figure 15 (c) and Figure 15 As shown in (d), when the clamping force increases to 5 kN and 10 kN, 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 10 kN, 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 (d). Figure 14 (d) and Figure 15 As shown in (d), the drift of the highest temperature point with increasing clamping force is consistent with the simulation results.

[0075] Lateral thermal coupling and vertical heat dissipation of press-fit IGBTs, such as Figure 16As shown, the collector-side contact thermal resistance is the same for both temperature sensor mounting positions. Lateral thermal coupling is unaffected by clamping force; the chip surface temperature distribution is primarily influenced by the emitter-side contact thermal resistance. At 0.25 kN, the lateral thermal coupling effect within the IGBT chip is greater than the vertical double-sided heat dissipation effect, resulting in the highest center temperature. Contact thermal resistance decreases with increasing clamping force; conversely, as clamping force increases, the vertical double-sided heat dissipation effect is enhanced, leading to a decrease in the chip center temperature.

[0076] To verify the feasibility of online temperature monitoring of the chip using a thermocouple located between the chip gate pad and the emitter molybdenum plate, the half-bridge inverter was operated at bus voltages of 100V, 200V, 300V, 400V, and 500V. Under different bus voltages, the load current of the PPIGBBT at 5kN is as follows: Figure 17 As shown, the measurement results of the thermocouple located between the chip gate pad and the emitter molybdenum sheet were recorded, as follows. Figure 18 As shown. To prevent thermal runaway failure of the PP IGBT, the bus voltage will not increase further.

[0077] More preferably, the above-mentioned temperature measuring device, including the press-fit IGBT device of 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 this application, and will not be described in detail here.

[0078] In summary, this application's embodiments demonstrate that the maximum temperature of the IGBT chip can be measured at the aforementioned gap by measuring and comparing temperatures at three different locations on the press-fit IGBT chip. Therefore, this application provides the aforementioned temperature measurement device. Based on this, the temperature measurement device provided by this application achieves online temperature monitoring of the press-fit IGBT chip through a physical contact method without interfering with the normal operation of the power converter. The integrated packaging technology of the press-fit IGBT chip and temperature sensor provided by this application can measure the maximum surface temperature of the press-fit IGBT chip. The above temperature measurement method is unaffected by mechanical stress, does not damage the temperature sensor, and ensures stable operation of the temperature sensor.

[0079] It should be understood that expressions such as "comprising" and "may include" used in this 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 this application, terms such as "comprising" and / or "having" are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0080] Furthermore, in this 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 this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. 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. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after connection. "Rotary connection" refers to a connection where the components can rotate relative to each other after connection. "Sliding connection" refers to a connection where the components can slide relative to each other after connection. The directional terms mentioned in the embodiments of this application, such as "top," "bottom," "inner," "outer," "left," and "right," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0082] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are limitations specific to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are permissible; approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable. For example, "A and B are parallel" 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" 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 description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A temperature measuring device for press-fitted IGBT chips, wherein the press-fitted IGBT device comprises: An IGBT chip and an emitter molybdenum sheet, wherein the IGBT chip includes a gate pad and an emitter pad, 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; characterized in that the measuring device includes a temperature sensor; The temperature sensor is used to measure the temperature of the IGBT chip when the gate spring pin head is opened in the gap between the gate pad and the preset area on the front side 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. No additional temperature sensor is required in the emitter molybdenum sheet; 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 extends into the area around the corner. When the clamping force on the IGBT chip exceeds a preset value, the maximum temperature of the IGBT chip is located at the gap between the emitter molybdenum sheet and the chip gate pad, and the temperature measured by the temperature sensor corresponds to the maximum temperature of the IGBT chip.

2. A press-fit IGBT chip, characterized in that, The device includes the temperature measuring device of claim 1, wherein the temperature sensor is disposed at the gap.

3. A packaging and integration device for pressing IGBT chips, characterized in that, include: Press-fit IGBT devices and the temperature measuring device according to claim 1; The temperature sensor is disposed at the gap, and the temperature sensor is synchronously packaged and integrated with the press-fit IGBT device.

4. A method for measuring the temperature of a press-fit IGBT chip, wherein the press-fit IGBT device comprises: An IGBT chip and an emitter molybdenum sheet, wherein the IGBT chip includes a gate pad and an emitter pad, the gate pad and the emitter pad being located on the front side of the chip, and the emitter molybdenum sheet being bonded to the emitter pad; characterized in that the method includes: A temperature sensor is placed in the gate spring pin head opening in the gap between the gate pad and the 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; No additional temperature sensor is required in the emitter molybdenum sheet; 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 extends into the area around the corner. When the clamping force on the IGBT chip exceeds a preset value, the maximum temperature of the IGBT chip is located at the gap between the emitter molybdenum sheet and the chip gate pad, and the temperature measured by the temperature sensor corresponds to the maximum temperature of the IGBT chip.

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