CN112151401B - A Grain Orientation Control Method Based on Semiconductor Temperature Control - Google Patents

Abstract

The invention discloses a crystal grain orientation control method based on semiconductor temperature control, which comprises the following steps that a first bonding pad, a soldering tin joint, a piece to be welded and a second bonding pad are welded and connected through vacuum brazing before heating and remelting; loading the power source on the first bonding pad, and generating Joule heat to remelt the soldering joint after the soldering joint is electrified; loading the power source on the first semiconductor refrigeration module and the second semiconductor refrigeration module, so that one surface of the first semiconductor refrigeration module attached to the first bonding pad heats, and one surface of the second semiconductor refrigeration module attached to the second bonding pad refrigerates, and forming a temperature gradient in the cooling process of the soldering joint; according to the solidification device provided by the invention, the power supply is applied to the first bonding pad and the second bonding pad, so that the joule heating remelting is realized by applying current to the soldering tin joint, the grain orientation of the soldering tin joint is rearranged, and the power fatigue damage resistance of the IGBT high-power component is improved.

Description

A Grain Orientation Control Method Based on Semiconductor Temperature Control

technical field

The invention relates to the field of metal welding technology, in particular to a method and device for controlling grain orientation based on semiconductor temperature control.

Background technique

Insulated Gate Bipolar Transistor (IGBT) is a composite fully-controlled-voltage-driven-power semiconductor composed of a bipolar junction transistor (BJT) and an insulated gate field effect transistor (MOS). The device has the advantages of small driving power and low saturation voltage. The interior contains several layers of structural materials with different functions. Usually, the soldering process is used to connect the lower surface of the chip with the insulating ceramic liner through the soldering layer (one-time welding), and connect the semiconductor chips in parallel to improve the current carrying capacity; the upper surface of the chip is made of Electrical interconnection is achieved by wire bonding (secondary soldering). IGBT power electronic devices will not only fail due to factors such as thermal fatigue and shear fatigue during actual work, but fatigue is also one of the key factors affecting device reliability. The fatigue failure of IGBT components will lead to the failure of related high-power electronic devices, which will have a serious impact in the field of control system reliability requirements. During the soldering and packaging process, the particle movement direction of the solder joint is scattered and uncontrollable, resulting in low reliability of fatigue resistance at the joint and greatly reducing the service life of the circuit.

Contents of the invention

In order to solve the technical problems existing in the prior art, the present invention provides a current-driven remelting and semiconductor temperature-controlled orientation that can rearrange the grain orientation of solder joints and improve the ability of components to resist power fatigue damage. Solidification device.

In order to achieve the purpose of the present invention, the device for zonal current-driven remelting and semiconductor temperature-controlled directional solidification provided here includes a first semiconductor refrigeration module, a second semiconductor refrigeration module, a first pad, a second pad and a solder joint; The first semiconductor refrigeration module is in contact with the upper surface of the first pad, the second semiconductor refrigeration module is in contact with the lower surface of the second pad, and the first pad and the The second pads are oppositely arranged; when the first pad and the second pad are powered on, the solder joint is resistive, and re-melted after being electrically heated, and the solder is in a fluid state; the first semiconductor When the power is loaded on the refrigeration module, the side attached to the first pad is heated; when the power is loaded on the second semiconductor refrigeration module, the side attached to the second pad is cooled, and the side of the solder joint is heated. A temperature gradient is formed during cooling.

The solidification device provided by the present invention applies power to the first pad and the second pad to apply current to the solder joint to achieve Joule heating and remelting, and then realizes the solder joint through the first semiconductor refrigeration module and the second semiconductor refrigeration module. The one-dimensional temperature gradient during the solidification process rearranges the grain orientation of the solder joints, improving the ability of IGBT high-power components to resist power fatigue damage.

Further, the first peltier cooling module includes a first peltier cooling submodule A and a first peltier refrigerating submodule B, and both the first peltier cooling submodule A and the first peltier cooling submodule B include a first peltier cooling submodule B. semiconductor cooler.

Further, the first semiconductor refrigeration sub-module A and the first semiconductor refrigeration sub-module B also include a first cooling chamber, and the first semiconductor refrigeration sheet is stacked with the first cooling chamber; the first A first cover plate is used to electrically isolate and conduct heat transfer between the semiconductive refrigerating sheet and the first cooling chamber.

Further, the first cooling chamber includes a serpentine flow pipe and a sealing groove for sealing the serpentine flow pipe, and two ends of the serpentine flow pipe are respectively provided with a cooling water inlet and a cooling water outlet.

Further, the contact surface between the first cooling cavity and the first cover plate is coated with thermal conductive silicone grease to improve thermal conductivity.

Further, the first semiconductor refrigeration sub-module A and the first semiconductor refrigeration sub-module B are independently loaded with power, and the power can be loaded only on the first semiconductor refrigeration sub-module A, or only on the first semiconductor refrigeration sub-module A. The cooling sub-module B, or loaded on the first semiconductor cooling sub-module A and the first semiconductor cooling sub-module B at the same time.

Further, the second peltier refrigeration module includes a second peltier refrigeration submodule A and a second peltier refrigeration submodule B, and both the second peltier refrigeration submodule A and the second peltier refrigeration submodule B include a second peltier refrigeration submodule B. piece.

Further, the second semiconductor cooling sub-module A and the second semiconductor cooling sub-module B also include a second cooling cavity, and the second semiconductor cooling sheet is stacked with the second cooling cavity; the second A second cover plate is used to electrically isolate and conduct heat transfer between the semiconductive cooling plate and the second cooling chamber.

Further, the second cooling chamber includes a serpentine flow pipe and a sealing groove for sealing the serpentine flow pipe, and two ends of the serpentine flow pipe are respectively provided with a cooling water inlet and a cooling water outlet.

Further, the contact surface between the second cooling cavity and the second cover plate is coated with thermal conductive silicone grease.

Further, the second semiconductor refrigeration sub-module A and the second semiconductor refrigeration sub-module B are independently loaded with power, and the power can be loaded only on the second semiconductor refrigeration sub-module A, or only on the second semiconductor refrigeration sub-module B. The cooling sub-module B, or loaded on the second semiconductor cooling sub-module A and the second semiconductor cooling sub-module B at the same time.

Furthermore, the device provided by the present invention also includes a power supply system, the power output by the power supply system is loaded on the first pad and the second pad on the one hand, and on the other hand is loaded on the first semiconductor cooling pad. module and the second peltier cooling module.

Further, the power system includes:

Host computer for human-computer interaction;

A single-chip microcomputer, used for communication connection with the upper computer, outputting a control signal according to the received control instruction sent by the upper computer, and uploading the received data to the upper computer;

heating and remelting power supply, the positive and negative electrodes are respectively electrically connected to the first pad and the second pad;

The relay is connected in series between the signal output terminal of the single-chip microcomputer and the heating and remelting power supply, and is turned on when the single-chip microcomputer outputs the control signal so that the control signal output by the single-chip microcomputer is loaded on the heating and remelting power supply. The output power of the heating and remelting power supply is loaded on the first pad and the second pad;

The digital-to-analog converter is connected to the signal output end of the single-chip microcomputer, and is used to convert the digital signal output by the single-chip microcomputer into an analog signal and load it on the first semiconductor refrigeration module and the second semiconductor refrigeration module respectively.

Further, the power supply system further includes a temperature acquisition device communicatively connected with the single chip microcomputer, the temperature acquisition device is used to acquire the temperature between the first pad and the second pad during the remelting process, and upload to the host computer through the single-chip microcomputer; according to the uploaded temperature data, input control instructions to the single-chip microcomputer through the upper computer, so that the output signal of the single-chip microcomputer is passed through the digital-to-analog converter while the relay is cut off. Afterwards, it is loaded on the first semiconductor refrigeration module and the second semiconductor refrigeration module, so that the first semiconductor refrigeration module is attached to the first welding pad for heating, and the second semiconductor refrigeration module is attached to the The side close to the second solder pad is refrigerated.

Further, the device provided by the present invention further includes a cooling water circulation machine communicatively connected with the host computer, and the flow rate of the cooling water of the cooling water circulation machine is controlled by the host computer.

The second object of the present invention here is to provide a method for controlling grain orientation based on semiconductor temperature control, the method comprising the following steps:

Step S1: Connecting the first pad, the solder joint, the piece to be welded and the second pad by vacuum brazing before heating and remelting;

Step S2: Apply power to the first pad, and the solder joint will re-melt due to Joule heat after electrification;

Step S3: After a certain period of time, load power on the first semiconductor refrigeration module and the second semiconductor refrigeration module, so that the first semiconductor refrigeration module is attached to the side of the first pad for heating, and the second semiconductor refrigeration module is attached to the first pad. One side of the two pads is refrigerated, forming a temperature gradient during the cooling of the solder joint.

Further, the vacuum brazing includes the following steps:

Step S11: Etch the solder material with 10% NaOH solution for 10 minutes to keep the solution temperature at 40-60°C, and then etch it in nitric acid + hydrofluoric acid solution for 5 minutes;

Step S12: Place the solder material processed in step S11 on the solder joint between the first pad, the solder joint, the piece to be welded and the second pad, place it in a vacuum brazing furnace after assembly, and provide A certain external pressure, when the vacuum in the brazing furnace is evacuated to below 6×10^(-3)Pa, start to heat up to the brazing temperature for brazing.

The beneficial effects of the present invention include:

1) Joule heating and remelting is achieved by applying current to the solder joint, and then the one-dimensional temperature gradient of the solder joint during the solidification process is realized through the first semiconductor refrigeration module and the second semiconductor refrigeration module, so that the grain orientation of the solder joint is re- Arrangement improves the ability of components to resist power fatigue damage.

2) The first semiconductor refrigeration module and the second semiconductor refrigeration module are independently controlled, which improves the independent controllability of the device.

3) The cooling cavity can dissipate heat from the hot end. When the cooling of the cold end of the semiconductor refrigeration module cannot meet the requirements, you can pass cooling water into the cooling cavity of the hot end. Conducted to the hot end, so when the hot end is cooled by the cooling chamber, the temperature of the cold end further drops, thereby further expanding the temperature gradient and accelerating solidification;

4) Using a single-chip microcomputer as the control module, combined with the temperature field data collected in real time by the temperature acquisition device, and controlling the work of the first semiconductor refrigeration module and the second semiconductor refrigeration module according to the temperature data, the PID of the temperature gradient during the solder joint remelting process is realized Closed-loop control.

5) The semiconductor temperature control module used in the present invention is small in size, and the range of temperature gradient can be controlled by adjusting the magnitude and direction of the current loaded on the first semiconductor refrigeration module and the second semiconductor refrigeration module through the cooperation of the single-chip microcomputer and the host computer. high.

6) The upper computer also controls the cooling water circulation speed of the cooling water circulation machine, so that the temperature gradient of the device can meet the cooling and solidification requirements.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description serve to explain the principles of the invention. Apparently, the drawings in the following description are only some embodiments of the invention, and those skilled in the art can obtain other drawings according to these drawings without creative efforts. In the attached picture:

FIG. 1 is a schematic diagram of the overall structure of a device for partitioned current-driven remelting and semiconductor temperature-controlled directional solidification provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of the first semiconductor refrigeration sub-module recorded in the embodiment of the present invention;

Fig. 3 is a schematic structural view of the second semiconductor refrigeration sub-module recorded in the embodiment of the present invention;

Fig. 4 is a schematic structural diagram of a cooling cavity recorded in an embodiment of the present invention;

In the drawings: 1-the first semiconductor refrigeration module, 11-the first semiconductor refrigeration sub-module A, 12-the first semiconductor refrigeration sub-module B, 111-the first semiconductor refrigeration sheet, 112-the first cooling cavity, 113-the first A cover plate, 2-the second semiconductor refrigeration module, 21-the second semiconductor refrigeration sub-module A, 22-the second semiconductor refrigeration sub-module B, 211-the second semiconductor refrigeration sheet, 212-the second cooling cavity, 213-the second cooling chamber Two cover plates, 3-first pad, 4-second pad, 5-solder joint, 6-piece to be welded, 7-host computer, 8-single-chip microcomputer, 9-heating and remelting power supply, 10-relay, 13 - temperature collection device, 14 - serpentine flow tube, 15 - sealing groove.

Detailed ways

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the concept of example embodiments to the Those skilled in the art.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided in order to give a thorough understanding of embodiments of the invention. One skilled in the art will appreciate, however, that the inventive solution may be practiced without one or more of the specific details, or that other approaches may be employed. In other instances, well-known methods, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the invention.

Referring to FIG. 1 , the partitioned current-driven remelting and semiconductor temperature-controlled directional solidification device provided by the present invention includes a first semiconductor refrigeration module 1, a second semiconductor refrigeration module 2, a first pad 3, a second pad 4 and Solder joint 5; the first semiconductor refrigeration module 1 is in contact with the upper surface of the first pad 3, the second semiconductor refrigeration module 2 is in contact with the lower surface of the second pad 4, the first pad 3 and the second The pads 4 are arranged oppositely, and the solder joint 5 is located between the first pad 3 and the second pad 4; when the first pad 3 and the second pad 4 are powered on, the solder joint 5 is resistive and is electrically heated After re-melting, the solder is in a flowing state; when the power is loaded, the first semiconductor refrigeration module 1 is attached to the side of the first pad 3 to heat; the second semiconductor refrigeration module 2 is attached to the second solder pad 3 when the power is loaded. One side of the disc 4 is cooled, creating a temperature gradient during the cooling of the solder joint 5 .

The working principle of the device is: using Joule heat heating and remelting to remelt and solidify the solder joints after brazing and welding, specifically: the first pad 3, the solder joint 5, the parts to be welded 6 and The second pad 4 is connected by vacuum brazing before heating and remelting; the power supply is applied to the first pad 3, so that a circuit is formed between the first pad 3 and the second pad 4 through a solder joint 5, and the solder joint 5 is resistive, and after electrification, it generates Joule heat to re-melt it. When the solder joint 5 is in a flowing state, cut off the power loaded on the first pad 3 and the second pad 4, and simultaneously refrigerate the first semiconductor. The module 1 and the second semiconductor refrigeration module 2 are powered on, so that the side of the first semiconductor refrigeration module 1 attached to the first pad 3 is heated, and the side of the second semiconductor refrigeration module 2 attached to the second pad 4 is cooled. During the cooling process of the solder joint 5, a temperature gradient is formed, so that the melted solder is recooled and solidified.

In this paper, the structures of the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2 are:

The first peltier cooling module 1 includes a first peltier cooling submodule A11 and a first peltier cooling submodule B12 , and both the first peltier cooling submodule A11 and the first peltier cooling submodule B12 include a first peltier cooling chip 111 .

In this paper, the first semiconductor refrigeration sub-module A11 and the first semiconductor refrigeration sub-module B12 are independently loaded with power, and the power can be loaded only on the first semiconductor refrigeration sub-module A11, or only on the first semiconductor refrigeration sub-module B12, or both The first semiconductor refrigeration sub-module A11 and the first semiconductor refrigeration sub-module B12.

The second peltier cooling module 2 includes a second peltier cooling submodule A21 and a second peltier cooling submodule B22 , both of which include a second peltier cooling submodule 221 .

In this paper, the second semiconductor refrigeration sub-module A21 and the second semiconductor refrigeration sub-module B22 are independently loaded with power, and the power can be loaded only on the second semiconductor refrigeration sub-module A21, or only on the second semiconductor refrigeration sub-module B22, or both The second semiconductor refrigeration sub-module A21 and the second semiconductor refrigeration sub-module B22.

The principle of the temperature gradient formed by the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2 in this paper is to use the semiconductor refrigeration sheet. The semiconductor refrigeration sheet is a cooling device composed of semiconductors, which is based on the Peltier effect of semiconductor materials. When the N-type semiconductor and the P-type semiconductor are connected in series to form a circuit and pass through a direct current, heat will be absorbed and released at both ends of the galvanic couple to achieve the purpose of temperature control. Among them, the Peltier effect is reversible. When the direction of the current is changed, the galvanic couple that releases heat and absorbs heat also changes, and the heat absorbed and released is proportional to the current intensity. Compared with other refrigeration and heating devices, semiconductor refrigeration chips have higher reliability without moving parts. Of course, other cooling and heating devices can also be used to replace the peltier in this article, as long as the remelted solder joint can be cooled and solidified.

In order to be able to achieve a lower temperature, the first semiconductor refrigeration sub-module A11 and the first semiconductor refrigeration sub-module B12 herein also include a first cooling cavity 112, and the second semiconductor refrigeration sub-module A21 and the second semiconductor refrigeration sub-module B22 also include a first semiconductor refrigeration sub-module B22. Two cooling chambers 212.

As shown in FIG. 2 , the first peltier refrigerating plate 111 and the first cooling cavity 112 are stacked; the first peltier cooling plate 111 and the first cooling cavity 112 are electrically isolated by a first cover plate 113 and conduct heat transfer.

In order to ensure heat transfer performance, thermal conductive silicone grease is coated on the contact surface between the first cooling chamber 112 and the first cover plate 113 .

As shown in FIG. 3 , the second semiconductor cooling plate 211 is stacked with the second cooling chamber 212 ; the second semiconductor cooling plate 211 and the second cooling cavity 212 are electrically isolated by a second cover plate 213 and conduct heat transfer.

Similarly, in order to ensure the heat transfer performance, the contact surface between the second cooling cavity 212 and the second cover plate 213 is coated with thermal conductive silicone grease.

As shown in Figure 4, the first cooling chamber 112 and the second cooling chamber 212 provided herein include a serpentine flow pipe 14, the serpentine flow pipe 14 is placed in the center of the cooling chamber and sealed with a sealing groove 15, the serpentine flow pipe 14 A cooling water inlet and a cooling water outlet are respectively opened at both ends. When the temperature needs to be lowered, the cooling water is introduced from the cooling water inlet and flows out from the cooling water outlet to form a cooling cycle.

The first cover plate 113 and the second cover plate 213 herein are insulating ceramic cover plates.

In this paper, power is applied to the first pad 3 and the second pad 4 , as well as the first peltier cooling module 1 and the second peltier cooling module 2 through the following power supply system.

The power system includes:

The host computer 7 is used for human-computer interaction;

The single-chip microcomputer 8 is used to communicate with the upper computer 7, output control signals according to the received control instructions sent by the upper computer 7, and upload the received data to the upper computer 7;

Heating and remelting power supply 9, the positive and negative poles are electrically connected to the first pad 3 and the second pad 4 respectively;

The relay 10 is connected in series between the signal output terminal of the single-chip microcomputer 8 and the heating and remelting power supply 9. When the single-chip microcomputer 8 outputs the control signal, it is turned on so that the control signal output by the single-chip microcomputer 8 is loaded on the heating and remelting power supply 9, and the heating and remelting power supply 9 outputs The power is loaded on the first pad 3 and the second pad 4;

The digital-to-analog converter is connected to the signal output terminal of the single-chip microcomputer 8, and is used to convert the digital signal output by the single-chip microcomputer 8 into an analog signal and load it on the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2 respectively, as the first semiconductor refrigeration module The working power supply of module 1 and the second semiconductor refrigeration module 2, the digital-to-analog converter is matched with the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2, and is used to independently provide the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2 provide working power.

When the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2 respectively include a plurality of semiconductor refrigeration sub-modules, the digital-to-analog converters are correspondingly matched with the semiconductor refrigeration sub-modules, and are used to independently provide working power for each semiconductor refrigeration sub-module; of course It is also possible for a digital-to-analog converter to provide working power for a semiconductor refrigeration module including multiple semiconductor refrigeration sub-modules, that is, a digital-to-analog converter provides working power for multiple semiconductor refrigeration sub-modules, but these multiple semiconductor refrigeration sub-modules should At the same time, it is included in the first peltier module 1 or the second peltier module 2 .

In order to enable the digital-to-analog converter to output a constant current power supply and ensure the stable operation of the semiconductor refrigeration module, the output of the digital-to-analog converter in this paper is also loaded on the first semiconductor refrigeration module 1 or the second semiconductor refrigeration module 2 after being passed through the operational amplifier; The output end is also connected to the signal input end of the single-chip microcomputer, and the single-chip microcomputer, the digital-to-analog converter, and the operational amplifier form a negative feedback system, and the single-chip microcomputer adjusts the output according to the current situation output by the operational amplifier, so that the load on the first semiconductor refrigeration module 1 or the second The current on the peltier module 2 remains constant.

Here, the number of operational amplifiers and digital-to-analog converters may or may not be matched.

The power supply system herein also includes a temperature acquisition device 13 that is communicatively connected with the single-chip microcomputer. The second pad 4 contacts.

The temperature acquisition device is used to collect the temperature between the first pad 3 and the second pad 4 in the remelting process, and upload it to the host computer 7 through the single-chip microcomputer 8; Input the control command to cut off the relay 10, and at the same time make the output signal of the single chip microcomputer 8 be loaded on the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module 2 through the digital-to-analog converter, so that the first semiconductor refrigeration module 1 is attached to the first semiconductor refrigeration module. One side of the pad 3 is heated, and the side of the second semiconductor refrigeration module 2 bonded to the second pad 4 is cooled.

The temperature sensor, single-chip microcomputer and semiconductor refrigeration module together form a closed-loop PID control system. When the solder joint is re-solidified, the staff inputs the temperature gradient data to the single-chip microcomputer through the host computer, and the single-chip microcomputer sends the first semiconductor refrigeration module and the second semiconductor refrigeration module Input the control current, the temperature acquisition device returns the temperature field data of the device to the single-chip microcomputer, and the single-chip microcomputer adjusts the output to the first semiconductor refrigeration module and the second semiconductor refrigeration module through the PID algorithm to make the temperature gradient between the two meet the user's needs.

The temperature collection device here uses an infrared camera, and of course other devices capable of collecting temperature can also be used.

According to the uploaded temperature data, the staff input control instructions to the single-chip microcomputer through the host computer to control the magnitude of the current loaded on the first semiconductor refrigeration module 1 and/or the second semiconductor refrigeration module 2, which is used to adjust the first semiconductor refrigeration module 1 and the second semiconductor refrigeration module. Temperature gradient between peltier modules 2.

Human-computer interaction is realized through the host computer, and a controllable temperature gradient is applied when the solder joint is solidified.

The device provided herein also includes a cooling water circulation machine communicated with the host computer, and the cooling water circulation machine is used to provide cooling water to the first cooling cavity and the second cooling cavity. The cooling water cycle machine used in this paper is an independent cooling water cycle machine, which is directly connected to the host computer through the USB port, and the cooling water flow rate of the cooling water cycle machine is manually controlled through the software installed on the host computer, so that the first semiconductor refrigeration module and the second semiconductor refrigeration module The temperature gradient between modules meets user requirements.

In this paper, when remelting and solidifying, it is necessary to connect the first pad, the solder joint, the piece to be welded, and the second pad by vacuum brazing before heating and remelting. The vacuum brazing connection here can use any One, where the following vacuum brazing is used:

Step S11: Etch the solder material with 10% NaOH solution for 10 minutes to keep the solution temperature at 40-60°C, and then etch it in nitric acid + hydrofluoric acid solution for 5 minutes;

Step S12: Place the solder material processed in step S11 on the solder joint between the first pad, the solder joint, the piece to be welded and the second pad, place it in a vacuum brazing furnace after assembly, and provide Under a certain external pressure, when the vacuum in the brazing furnace is pumped below 6×10^(-3)Pa, it starts to heat up to the brazing temperature for brazing. After the brazing is completed, the sample is cooled to room temperature with the furnace and taken out.

In this paper, vacuum brazing can be used to ensure that oxidation will not occur during the welding process, and other welding methods can also be used to replace it.

In order to ensure that the part 6 to be welded will not fall off during the remelting and solidification process, a pressure loading device is used to apply pressure to the first pad, the second pad, the solder joint and both ends of the part to be welded during the remelting and solidification process. The end surface of the solder joint and the first pad, as well as between the part to be welded and the part to be welded and the second pad are always compressed during the heating and remelting process. The pressure loading device is not special, as long as the weldment does not fall off during the heating and remelting process.

The partitioned current-driven remelting and semiconductor temperature-controlled directional solidification device provided in this paper overcomes the problem of uncontrollable grain orientation in the traditional metal welding process and improves the reliability of the welding joint; the device provided in this paper is used for IGBT high-power components Manufactured to solve the problem that the grain orientation of the solder joints of IGBT high-power components diverges and cannot be controlled during the welding process, resulting in flattening and polarization of copper-tin crystals under high current density conditions under thermal fatigue growth phenomenon that reduces the reliability of circuit components.

The present disclosure has been described by the above-mentioned related embodiments, but the above-mentioned embodiments are only examples for implementing the present disclosure. It must be pointed out that the disclosed embodiments do not limit the scope of the present disclosure. On the contrary, changes and modifications made without departing from the spirit and scope of the present disclosure all belong to the patent protection scope of the present disclosure.

Claims (10)

1. A current-driven remelting and semiconductor temperature control directional solidification device is characterized in that: the device comprises a first semiconductor refrigeration module (1), a second semiconductor refrigeration module (2), a first bonding pad (3), a second bonding pad (4) and a soldering joint (5); the first semiconductor refrigeration module (1) is in fit contact with the upper surface of the first bonding pad (3), the second semiconductor refrigeration module (2) is in fit contact with the lower surface of the second bonding pad (4), and the first bonding pad (3) and the second bonding pad (4) are oppositely arranged; when the power supply is loaded, the first bonding pad (3) and the second bonding pad (4) are resistive, the soldering tin joint (5) is melted again after being electrically heated, and soldering tin is in a flowing state; when the power supply is loaded, the first semiconductor refrigeration module (1) is attached to one surface of the first bonding pad (3) for heating; and the second semiconductor refrigeration module (2) is attached to one surface of the second bonding pad (4) for refrigeration when a power supply is loaded, and a temperature gradient is formed in the cooling process of the soldering tin joint (5) so as to rearrange the grain orientation of the soldering tin joint (5).

2. The current-driven reflow and semiconductor temperature-controlled directional solidification apparatus of claim 1 wherein: the first semiconductor refrigeration module (1) comprises a first semiconductor refrigeration sub-module A (11) and a first semiconductor refrigeration sub-module B (12), and the first semiconductor refrigeration sub-module A (11) and the first semiconductor refrigeration sub-module B (12) comprise a first semiconductor refrigeration sheet (111).

3. The current-driven remelting and semiconductor temperature-controlled directional solidification apparatus of claim 2 wherein: the first semiconductor refrigeration sub-module A (11) and the first semiconductor refrigeration sub-module B (12) further comprise a first cooling cavity (112), and the first semiconductor refrigeration sheet (111) and the first cooling cavity (112) are arranged in a stacked mode; the first semiconductor refrigerating sheet (111) and the first cooling cavity (112) are electrically isolated by a first cover plate (113) and are subjected to heat transfer.

4. The current-driven reflow and semiconductor temperature-controlled directional solidification apparatus of claim 1 wherein: the second semiconductor refrigeration module (2) comprises a second semiconductor refrigeration sub-module A (21) and a second semiconductor refrigeration sub-module B (22), and the second semiconductor refrigeration sub-module A (21) and the second semiconductor refrigeration sub-module B (22) comprise second semiconductor refrigeration sheets (211).

5. The current-driven reflow and semiconductor temperature-controlled directional solidification apparatus of claim 4 wherein: the second semiconductor refrigeration sub-module A (21) and the second semiconductor refrigeration sub-module B (22) further comprise a second cooling cavity (212), and the second semiconductor refrigeration piece (211) and the second cooling cavity (212) are stacked; the second semiconductor refrigerating sheet (211) and the second cooling cavity (212) are electrically isolated by a second cover plate (213) and are used for heat transfer.

6. The current-driven reflow and semiconductor temperature-controlled directional solidification apparatus of claim 4 wherein: the second semiconductor refrigeration sub-module A (21) and the second semiconductor refrigeration sub-module B (22) independently load power, and the power can be loaded on the second semiconductor refrigeration sub-module A (21) only, the second semiconductor refrigeration sub-module B (22) only or the second semiconductor refrigeration sub-module A (21) and the second semiconductor refrigeration sub-module B (22) simultaneously.

7. The current-driven remelting and semiconductor temperature-controlled directional solidification apparatus of any one of claims 1-6 wherein: the semiconductor refrigerating module further comprises a power supply system, wherein power output by the power supply system is loaded on the first bonding pad (3) and the second bonding pad (4) on one hand, and on the other hand, the power output by the power supply system is loaded on the first semiconductor refrigerating module (1) and the second semiconductor refrigerating module (2) on the other hand.

8. The current-driven reflow and semiconductor temperature-controlled directional solidification apparatus of claim 7, wherein the power system comprises:

the upper computer is used for man-machine interaction;

the singlechip is used for being in communication connection with the upper computer, outputting a control signal according to a received control instruction sent by the upper computer, and uploading received data to the upper computer;

a heating remelting power supply, wherein the anode and the cathode are respectively electrically connected with the first bonding pad (3) and the second bonding pad (4); the relay is connected in series between the heating remelting power supplies at the signal output end of the singlechip, and is conducted when the singlechip outputs a control signal so that the control signal output by the singlechip is loaded on the heating remelting power supplies, and the heating remelting power supply output power supplies are loaded on the first bonding pad (3) and the second bonding pad (4); the digital-analog converter is connected with the signal output end of the singlechip and is used for converting digital signals output by the singlechip into analog signals which are respectively loaded on the first semiconductor refrigeration module (1) and the second semiconductor refrigeration module (2).

9. The current-driven reflow and semiconductor temperature-controlled directional solidification apparatus of claim 8 wherein: the power supply system further comprises a temperature acquisition device which is in communication connection with the singlechip, wherein the temperature acquisition device is used for acquiring the temperature between the first bonding pad (3) and the second bonding pad (4) in the remelting process and uploading the temperature to the upper computer through the singlechip; according to the uploaded temperature data, a control instruction is input to the singlechip through the upper computer, so that the relay is cut off, meanwhile, an output signal of the singlechip is loaded on the first semiconductor refrigeration module (1) and the second semiconductor refrigeration module (2) after passing through the digital-to-analog converter, the first semiconductor refrigeration module (1) is attached to one side of the first bonding pad (3) for heating, and the second semiconductor refrigeration module (2) is attached to one side of the second bonding pad (4) for refrigerating.

10. A method of controlling grain orientation based on semiconductor temperature control, comprising a current driven remelting and semiconductor temperature controlled directional solidification apparatus according to any one of claims 1-9, characterized in that the method comprises the steps of:

step S1: the first bonding pad, the soldering joint, the piece to be welded and the second bonding pad are welded and connected through vacuum brazing before heating and remelting;

step S2: loading the power source on the first bonding pad, and generating Joule heat to remelt the soldering joint after the soldering joint is electrified;

step S3: after a certain time, the power source is loaded on the first semiconductor refrigeration module and the second semiconductor refrigeration module, so that one surface of the first semiconductor refrigeration module attached to the first bonding pad heats, and the other surface of the second semiconductor refrigeration module attached to the second bonding pad refrigerates, and a temperature gradient is formed in the cooling process of the soldering joint.