A Micro Solder Joint Thermal Migration Device Based on the Peltier Effect and Its Testing Method

Abstract

The present invention discloses a micro-solder joint thermal migration device based on the Peltier effect and a testing method thereof. By using the heating structure and the cooling structure to abut against the specimen, after the device is powered on, a thermal migration test is carried out, and after recording the corresponding temperature, finite element electro-thermal coupling analysis is used to obtain the temperature gradient of the solder joint of the specimen, so as to obtain reliable and stable micro-solder joint thermal migration data; according to the Peltier effect, the load current is changed to control the temperature difference between the hot and cold ends of the solder joint to obtain a larger temperature gradient; different temperature gradients can also be obtained by controlling the height of the solder joint; at the same time, the external reinforcement plate assembly is used for clamping and fixing, and the structure is simple, solving the technical problems of the complex structure of the thermal migration device and the difficult control of the temperature gradient in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic packaging, and particularly to a micro-solder joint thermal migration device based on the Peltier effect and a testing method therefor. Background Art

[0002] As the electronic packaging system continues to develop towards miniaturization, high performance, and high reliability, the increasing number of transistors and the continuous reduction of solder joint size have made the impact of thermal migration problems on solder joint reliability increasingly prominent. Thermal migration refers to the phenomenon that atoms migrate directionally under the drive of a temperature gradient in the presence of a temperature difference. In an electronic packaging system, the main reasons for forming a temperature gradient at both ends of a solder joint include: 1) When an electronic product is working, the Joule heat generated by transistors on the chip side is greater than the Joule heat generated by the substrate, thus forming a temperature gradient at both ends of the solder joint; 2) Due to the different resistivity and size of each part of the material, the Joule heat generated by the chip during operation is unevenly distributed, forming a temperature gradient at both ends of the solder joint; 3) When the current density passes through the solder joint, due to the influence of structural factors, etc., the current density distribution will be uneven, resulting in uneven distribution of Joule heat, causing a large temperature gradient to form on both sides of the solder joint. Research has confirmed that thermal migration will cause voids at the hot end of the solder joint, leading to solder joint failure.

[0003] In the related research on the problem of solder joint thermal migration failure, how to obtain a relatively high and stable temperature gradient and conduct thermal migration testing has always been a concern for researchers. Currently, some researchers use the method of water cooling one end of the solder joint and not performing any treatment on the other end to form a certain temperature gradient. However, the structure of water cooling is complex, with a large volume, and the formed temperature gradient is not easy to control. There are also researchers who heat using a ceramic heating sheet, monitor the temperature of the ceramic heating sheet with a thermocouple and feedback it to a temperature controller, and the temperature controller controls the temperature of the ceramic heating sheet according to the feedback temperature to form a temperature difference. However, the temperature difference between the two ends of the solder joint generated by this method is small, and the formed temperature gradient is relatively small. In addition, existing thermal migration devices usually include: a heating structure, a lower heat conduction plate, a specimen, an upper heat conduction plate, and a cooling structure. These thermal migration devices often have certain drawbacks: 1) The volume of the heating mechanism and the cooling mechanism is large, and the structure is relatively complex, increasing the volume of the thermal migration device; 2) The position for placing the specimen between the heating structure and the cooling structure is not easy to adjust, and it will no longer be suitable for the height of other solder joints after the device is installed; 3) It is inconvenient to fixedly install the thermal migration device, and the non-fixed device is likely to cause problems such as inaccurate positioning and inconvenient use.

[0004] The Peltier effect refers to the phenomenon that when an electric current passes through a loop composed of different conductors, in addition to the irreversible Joule heat generated, at the joints of different conductors, heat absorption and heat release phenomena will occur respectively depending on the direction of the current. According to the Peltier effect, when an electric current is applied to a conductor, a temperature difference will be generated at both ends of the conductor, thereby forming a temperature gradient at both ends of the solder joint. Utilizing the Peltier effect to obtain the temperature gradient at both ends of the solder joint can avoid using a large-sized heating or cooling structure. Summary of the Invention

[0005] The purpose of the present invention is to provide a micro-solder joint heat migration device based on the Peltier effect and its testing method, aiming to solve the technical problems of the complex structure of the heat migration device and the difficult control of the temperature gradient in the prior art.

[0006] To achieve the above object, a micro-solder joint heat migration device based on the Peltier effect adopted by the present invention includes a heat generating structure, a heat cooling structure, a specimen, and a reinforcement plate assembly. The heat generating structure and the heat cooling structure are arranged up and down, the heat generating structure is located below the heat cooling structure, the specimen is arranged between the heat generating structure and the heat cooling structure, and the reinforcement plate assembly clamps the heat generating structure and the heat cooling structure from both the upper and lower sides respectively;

[0007] The reinforcement plate assembly includes a first metal plate, a second metal plate, and four groups of connecting bolts. The first metal plate and the second metal plate are arranged oppositely. The first metal plate abuts against the heat generating structure, the second metal plate abuts against the heat cooling structure, and the four groups of connecting bolts respectively penetrate through the first metal plate and the second metal plate and are movably connected, and a suitable nut is arranged on each group of connecting bolts.

[0008] Among them, the heat generating structure includes a first heat generating substrate, a second heat generating substrate, a third heat generating substrate, a plurality of heat generating plate P-type semiconductors, and a plurality of heat generating plate N-type semiconductors. The first heat generating substrate, the second heat generating substrate, and the third heat generating substrate are arranged oppositely in pairs. The first heat generating substrate is located above the second heat generating substrate, the third heat generating substrate is located below the second heat generating substrate, the gaps from the second heat generating substrate to the first heat generating substrate and the third heat generating substrate are equal, the heat generating plate P-type semiconductors and the heat generating plate N-type semiconductors are arranged in the gaps, the number of the heat generating plate P-type semiconductors and the heat generating plate N-type semiconductors in the gaps is adapted, and heat generating plate copper wirings are arranged between each pair of the heat generating plate P-type semiconductors and the heat generating plate N-type semiconductors.

[0009] Among them, the refrigeration structure includes a first refrigeration substrate, a second refrigeration substrate, a third refrigeration substrate, a plurality of P-type semiconductor refrigeration plates and a plurality of N-type semiconductor refrigeration plates. The first refrigeration substrate, the second refrigeration substrate and the third refrigeration substrate are arranged opposite to each other in pairs. The first refrigeration substrate is located below the second refrigeration substrate, and the third refrigeration substrate is located above the second refrigeration substrate. The gaps between the second refrigeration substrate and the first refrigeration substrate and the third refrigeration substrate are equal. The P-type semiconductor refrigeration plates and the N-type semiconductor refrigeration plates are arranged in the gaps, and the numbers of the P-type semiconductor refrigeration plates and the N-type semiconductor refrigeration plates in the gaps are adapted. Refrigeration plate copper wirings are arranged between each pair of the P-type semiconductor refrigeration plates and the N-type semiconductor refrigeration plates.

[0010] Among them, the specimen includes a first PCB board, a second PCB board and a plurality of solder joints. The first PCB board and the second PCB board are arranged opposite to each other. The solder joints are arranged between the first PCB board and the second PCB board. The plurality of solder joints are arranged in an array. Copper wirings are arranged on both the first PCB board and the second PCB board. The plurality of solder joints are connected by copper wirings to form a conductive loop.

[0011] Among them, the heating structure and the refrigeration structure are connected by wires, and the sizes of the heating structure and the refrigeration structure are adapted.

[0012] Among them, thermal conductive grease is coated on the contact surface between the first heating substrate and the first metal plate, thermal conductive grease is coated on the contact surface between the third refrigeration substrate and the second metal plate, and thermal conductive grease is coated on the contact surfaces of the specimen with the heating structure and the refrigeration structure.

[0013] The present invention also provides a test method for a micro solder joint thermal migration device based on the Peltier effect as described above, and the steps are as follows:

[0014] Step 1: Horizontally place the first metal plate and place the heating structure on the first metal plate;

[0015] Step 2: Place the specimen on the heating structure;

[0016] Step 3: Place the refrigeration structure above the specimen, and place the refrigeration structure and the heating structure overlapping and aligned;

[0017] Step 4: Place the second metal plate above the refrigeration structure;

[0018] Step 5: Use four groups of the connecting bolts to connect the first metal plate and the second metal plate, and tighten the nuts;

[0019] Step 6: Connect the positive and negative poles of the power supply through the copper wiring of the heating plate, and connect them to a pair of the P-type semiconductor of the heating plate and the N-type semiconductor of the heating plate in the heating structure, and connect to direct current;

[0020] Step 7: Start the heat migration test, and use a thermocouple thermometer to measure the temperatures of the third heating substrate and the first cooling substrate;

[0021] Step 8: Perform simulation using finite element software; take the measured temperature as the boundary condition of the sample solder joint, and through finite element electro-thermal coupling analysis, the temperature gradient of the sample solder joint can be obtained, so as to obtain reliable and stable micro-solder joint heat migration data.

[0022] A micro-solder joint heat migration device based on the Peltier effect and its testing method of the present invention hold the sample by using the heating structure and the cooling structure. After the device is powered on, a heat migration test is carried out. After recording the corresponding temperature, finite element electro-thermal coupling analysis is used to obtain the temperature gradient of the sample solder joint, so as to obtain reliable and stable micro-solder joint heat migration data; according to the Peltier effect, the loading current is changed to control the temperature difference between the hot and cold ends of the solder joint to obtain a larger temperature gradient; different temperature gradients can also be obtained by controlling the height of the solder joint; at the same time, the external use of the reinforcement plate assembly for clamping and fixing has a simple structure, and solves the technical problems of complex structure and difficult temperature gradient control in the prior art. Description of the Drawings

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0024] Figure 1 is a schematic structural diagram of a micro-solder joint heat migration device based on the Peltier effect of the present invention.

[0025] Figure 2 is a schematic structural diagram of the second metal plate of the present invention.

[0026] Figure 3 is a schematic structural diagram of the first heating substrate of the heating structure of the present invention.

[0027] Figure 4 is a top view of the second heating substrate of the heating structure of the present invention.

[0028] Figure 5 is a bottom view of the second heating substrate of the heating structure of the present invention.

[0029] Figure 6 It is a schematic structural diagram of the third heat-generating substrate of the heat-generating structure of the present invention.

[0030] Figure 7 It is a schematic structural diagram of the first cooling substrate of the cooling structure of the present invention.

[0031] Figure 8 It is a top view of the second cooling substrate of the cooling structure of the present invention.

[0032] Figure 9 It is a bottom view of the second cooling substrate of the cooling structure of the present invention.

[0033] Figure 10 It is a schematic structural diagram of the third cooling substrate of the cooling structure of the present invention.

[0034] Figure 11 It is a schematic diagram when the sample is loaded with current in the present invention.

[0035] Figure 12 It is a step flow chart of the test method of the present invention.

[0036] 1 - Heat-generating structure, 11 - First heat-generating substrate, 12 - Second heat-generating substrate, 13 - Third heat-generating substrate, 14 - Heat-generating plate P-type semiconductor, 15 - Heat-generating plate copper wiring, 16 - Heat-generating plate N-type semiconductor, 2 - Cooling structure, 21 - First cooling substrate, 22 - Second cooling substrate, 23 - Third cooling substrate, 24 - Cooling plate P-type semiconductor, 25 - Cooling plate copper wiring, 26 - Cooling plate N-type semiconductor, 3 - Sample, 31 - First PCB board, 32 - Second PCB board, 33 - Copper wiring, 34 - Solder joint, 4 - Wire, 5 - Second metal plate, 6 - Thermal grease, 70 - Connecting bolt, 71 - Nut, 72 - Bolt hole, 8 - First metal plate. Detailed implementation manners

[0037] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0038] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, 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 should not be construed as a limitation to the present invention. In addition, in the description of the present invention, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0039] Please refer to Figures 1 to 11 , the present invention provides a micro-solder joint heat migration device based on the Peltier effect, including a heating structure 1, a cooling structure 2, a specimen 3 and a reinforcement plate assembly. The heating structure 1 and the cooling structure 2 are arranged up and down, the heating structure 1 is located below the cooling structure 2, the specimen 3 is arranged between the heating structure 1 and the cooling structure 2, and the reinforcement plate assembly clamps the heating structure 1 and the cooling structure 2 from the upper and lower sides respectively;

[0040] The reinforcement plate assembly includes a first metal plate 8, a second metal plate 5 and four groups of connecting bolts 70. The first metal plate 8 and the second metal plate 5 are arranged oppositely. The first metal plate 8 abuts against the heating structure 1, the second metal plate 5 abuts against the cooling structure 2, and the four groups of connecting bolts 70 respectively penetrate through the first metal plate 8 and the second metal plate 5 and are movably connected. Each group of connecting bolts 70 is provided with a matching nut 71.

[0041] In this embodiment, the micro-solder joint heat migration device based on the Peltier effect is composed of four components. The specimen 3 is located in the center. The lower part of the specimen 3 is in contact with the heating structure 1, and the upper part of the specimen 3 is in contact with the cooling structure 2. The reinforcement plate assembly clamps the heating structure 1 and the cooling structure 2 from the outside to form a whole;

[0042] The materials of the first metal plate 8 and the second metal plate 5 are pure copper, and the sizes are both 60mm×40mm×2mm. The four groups of connecting bolts 70 penetrate through the bolt holes 72 of the first metal plate 8 and the second metal plate 5. By tightening or loosening the nuts 71, the distance between the heating structure 1 and the cooling structure 2 can be adjusted to adapt to the heat migration tests of specimens 3 with various different heights. The connecting bolts 70 are also copper bolts with heat conduction performance, which helps with heat conduction while playing a positioning role.

[0043] Further, the heating structure 1 includes a first heating substrate 11, a second heating substrate 12, a third heating substrate 13, a plurality of P-type semiconductor heating plates 14, and a plurality of N-type semiconductor heating plates 16. The first heating substrate 11, the second heating substrate 12, and the third heating substrate 13 are arranged opposite to each other in pairs. The first heating substrate 11 is located above the second heating substrate 12, and the third heating substrate 13 is located below the second heating substrate 12. The gaps between the second heating substrate 12 and the first heating substrate 11 and the third heating substrate 13 are equal. The P-type semiconductor heating plates 14 and the N-type semiconductor heating plates 16 are arranged in the gaps, and the numbers of the P-type semiconductor heating plates 14 and the N-type semiconductor heating plates 16 in the gaps are adapted. A copper wiring 15 for the heating plate is provided between each pair of the P-type semiconductor heating plates 14 and the N-type semiconductor heating plates 16.

[0044] In this embodiment, a plurality of pairs of the P-type semiconductor cooling plates 14 and the N-type semiconductor cooling plates 16 are provided in the gaps between the first cooling substrate 21, the second cooling substrate 22, and the third cooling substrate 23. The P-type semiconductor cooling plates 14, the N-type semiconductor cooling plates 16, and the copper wiring 25 for the cooling plate form a pair of cooling plate thermocouples. The current direction of the cooling plate thermocouple is from the P-type semiconductor cooling plate 14 to the N-type semiconductor cooling plate 16. The lower end of the cooling structure 2 absorbs heat, and the upper end dissipates heat to form a hot end; a plurality of pairs of cooling plate thermocouples are stacked to form an array, increasing the temperature of the cooling structure 2 and obtaining a larger temperature difference value.

[0045] Further, the cooling structure 2 includes a first cooling substrate 21, a second cooling substrate 22, a third cooling substrate 23, a plurality of P-type semiconductor cooling plates 24, and a plurality of N-type semiconductor cooling plates 26. The first cooling substrate 21, the second cooling substrate 22, and the third cooling substrate 23 are arranged opposite to each other in pairs. The first cooling substrate 21 is located below the second cooling substrate 22, and the third cooling substrate 23 is located above the second cooling substrate 22. The gaps between the second cooling substrate 22 and the first cooling substrate 21 and the third cooling substrate 23 are equal. The P-type semiconductor cooling plates 24 and the N-type semiconductor cooling plates 26 are arranged in the gaps, and the numbers of the P-type semiconductor cooling plates 24 and the N-type semiconductor cooling plates 26 in the gaps are adapted. A copper wiring 25 for the cooling plate is provided between each pair of the P-type semiconductor cooling plates 24 and the N-type semiconductor cooling plates 26.

[0046] In this embodiment, several pairs of P-type semiconductor 24 and N-type semiconductor 26 of the cooling plate are arranged in the gap between the first cooling substrate 21, the second cooling substrate 22 and the third cooling substrate 23. The P-type semiconductor 24 of the cooling plate, the N-type semiconductor 26 of the cooling plate and the copper wiring 25 of the cooling plate form a pair of thermocouples of the cooling plate. The current direction of the thermocouple of the cooling plate is from the P-type semiconductor 24 of the cooling plate to the N-type semiconductor 26 of the cooling plate. The upper end of the cooling structure 2 dissipates heat, and the lower end absorbs heat to form a cold end; by superimposing several pairs of thermocouples of the cooling plate to form an array, the temperature of the cooling structure 2 can be reduced to a lower level, so as to obtain a larger temperature difference value.

[0047] Further, by superimposing two or more layers of thermocouple arrays of heating plates or cooling plates, the temperature difference between the hot and cold ends can be increased. The temperature difference ΔT at both ends of the specimen 3 can reach 68°C to 95°C. According to the temperature gradient calculation formula: grad T = ΔT / h (where h is the thickness of the specimen 3), the temperature gradient at both ends of the specimen 3 can be calculated.

[0048] Further, the materials of the P-type semiconductor and the N-type semiconductor are both ternary solid solution alloys based on bismuth telluride (Bi2Te3); preferably, the material of the P-type semiconductor is Bi2Te3-Sb2Te3; the material of the N-type semiconductor is Bi2Te3-Bi2Se3.

[0049] Further, the specimen 3 includes a first PCB board 31, a second PCB board 32 and several solder joints 34. The first PCB board 31 and the second PCB board 32 are arranged oppositely. The solder joints 34 are arranged between the first PCB board 31 and the second PCB board 32. Several solder joints 34 are arranged in an array. Copper wirings 33 are arranged on both the first PCB board 31 and the second PCB board 32. The several solder joints 34 are connected by the copper wirings 33 to form a conductive loop.

[0050] In this embodiment, the first PCB board 31 and the second PCB board 32 have the same size. The first PCB board 31 and the second PCB board 32 are overlapped. The first PCB board 31 is located above the second PCB board 32. Several solder joints 34 are arrayed between the first PCB board 31 and the second PCB board 32. The solder of the solder joints 34 is selected from leaded solder or lead-free solder in binary alloy or multi-alloy to detect the thermal migration performance of different micro-solder joints. The first PCB board 31, the second PCB board 32, the solder joints 34 and the copper wirings 33 are connected to form an electric current loop. The specimen 3 can be tested with or without power supply. After the specimen 3 is powered on, micro-solder joint electromigration test can be carried out, and then the influence of current load on micro-solder joint thermal migration can be evaluated.

[0051] Further, the heat generating structure 1 and the refrigerating structure 2 are connected by a wire 4.

[0052] In this embodiment, the wire 4 connects the circuits between the heat generating structure 1 and the refrigerating structure 2, forming a closed loop within the Peltier effect-based micro-solder joint heat migration device. When direct current is connected, the power supply flows in from the positive pole, passes through each layer of thermocouple arrays, and then flows out from the negative pole. The heat generating structure 1 and the refrigerating structure 2 are of matching size and the same size, and are arranged correspondingly in structure, with a simple design and easy installation.

[0053] Further, a thermal grease 6 is coated on the contact surface between the first heat generating substrate 11 and the first metal plate 8, a thermal grease 6 is coated on the contact surface between the third refrigerating substrate 23 and the second metal plate 5, and a thermal grease 6 is coated on the contact surfaces of the specimen 3 with the heat generating structure 1 and the refrigerating structure 2.

[0054] In this embodiment, a layer of thermal grease 6 is coated on the contact surface to ensure good heat transfer contact, reduce heat dissipation, ensure the accuracy when measuring the temperatures of the heat generating structure 1 and the refrigerating structure 2, and guarantee the accuracy of the analysis data.

[0055] Further, the first heat generating substrate 11, the second heat generating substrate 12, the third heat generating substrate 13, the first refrigerating substrate 21, the second refrigerating substrate 22, and the third refrigerating substrate 23 adopt direct plate copper (DPC) ceramic substrates, and their material is alumina. The sizes of the ceramic substrates are 40mm×40mm×1mm and 30mm×30mm×1mm.

[0056] In this embodiment, the manufacturing process steps of the first heat generating substrate 11, the second heat generating substrate 12, the third heat generating substrate 13, the first refrigerating substrate 21, the second refrigerating substrate 22, and the third refrigerating substrate 23 are as follows:

[0057] Step 1: Pretreat and clean the alumina ceramic substrate.

[0058] Step 2: Use thin film manufacturing technology, i.e., vacuum coating method, to sputter and deposit a copper metal composite layer on the ceramic substrate.

[0059] Step 3: Use photoresist to form a coating layer on the ceramic substrate, expose and develop to form electroplated copper; then use etching and stripping processes to complete the circuit production.

[0060] Step 4: Finally, increase the thickness of the circuit by electroplating and electroless plating deposition methods.

[0061] Step Five: After removing the photoresist, the production of the metallized circuit is completed.

[0062] The final product has excellent electrical and thermal conductivity of copper.

[0063] Please refer to Figure 12 , the present invention also provides a test method for a micro-solder joint thermal migration device based on the Peltier effect as described above, and the steps are as follows:

[0064] S1: Horizontally place the first metal plate 8, and place the heating structure 1 on the first metal plate 8;

[0065] S2: Place the specimen 3 on the heating structure 1;

[0066] S3: Place the cooling structure 2 above the specimen 3, and the cooling structure 2 and the heating structure 1 are overlapped and aligned;

[0067] S4: Place the second metal plate 5 above the cooling structure 2;

[0068] S5: Use four sets of the connecting bolts 70 to connect the first metal plate 8 and the second metal plate 5, and tighten the nuts 71;

[0069] S6: Connect the positive and negative poles of the power supply through the heating plate copper wiring 15, and connect them to a pair of the heating P-type semiconductors and the N-type semiconductors in the heating structure 1, and connect direct current;

[0070] S7: Start the thermal migration test, and use a thermocouple thermometer to measure the temperatures of the third heating substrate 13 and the first cooling substrate 21;

[0071] S8: Perform simulation using finite element software; use the measured temperature as the boundary condition of the specimen solder joint, and through finite element electro-thermal coupling analysis, the temperature gradient of the specimen solder joint can be obtained, so as to obtain reliable and stable micro-solder joint thermal migration data.

[0072] Among them, when simulation tests are needed, the specimen 3 to be tested can be selected first, and according to the operations in steps 1 to 5 above, the micro-solder joint thermal migration device based on the Peltier effect is assembled. Then, connect the direct current to the heating plate copper wiring 15 on the heating structure 1, start the thermal migration test, use a thermocouple thermometer to measure the temperatures of the third heating substrate 13 and the first cooling substrate 21, use this data as the boundary condition of the specimen solder joint, perform simulation using the finite element CAE software ANSYS, and obtain the temperature gradient of the specimen solder joint through finite element electro-thermal coupling analysis, and finally obtain reliable and stable micro-solder joint thermal migration data.

[0073] The present invention has the advantages of simple structure, small volume, wide temperature difference range generated and large temperature gradient obtained; not only can it be used for testing the heat transfer performance, but also the influence of current load on the heat transfer of micro-solder joints can be evaluated after connecting the specimen 3 to the power supply.

[0074] The above-disclosed is only a preferred embodiment of the present invention, and of course, the scope of the rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. A micro-solder joint thermal migration device based on the Peltier effect, characterized in that it includes a heating structure, a cooling structure, a specimen and a reinforcement plate assembly. The heating structure and the cooling structure are arranged vertically, with the heating structure located below the cooling structure. The specimen is arranged between the heating structure and the cooling structure, and the reinforcement plate assembly clamps the heating structure and the cooling structure from the upper and lower sides respectively; The reinforcement plate assembly includes a first metal plate, a second metal plate and four sets of connecting bolts. The first metal plate and the second metal plate are arranged oppositely. The first metal plate abuts against the heating structure, and the second metal plate abuts against the cooling structure. The four sets of connecting bolts respectively pass through the first metal plate and the second metal plate and are movably connected, and each set of connecting bolts is provided with a matching nut. The heating structure includes a first heating substrate, a second heating substrate, a third heating substrate, a number of heating plate P-type semiconductors and a number of heating plate N-type semiconductors. The first heating substrate, the second heating substrate and the third heating substrate are arranged oppositely in pairs. The first heating substrate is located above the second heating substrate, and the third heating substrate is located below the second heating substrate. The gaps from the second heating substrate to the first heating substrate and the third heating substrate are equal. The heating plate P-type semiconductors and the heating plate N-type semiconductors are arranged in the gaps, and the numbers of the heating plate P-type semiconductors and the heating plate N-type semiconductors in the gaps are matched. Heating plate copper wiring is arranged between each pair of the heating plate P-type semiconductors and the heating plate N-type semiconductors; The cooling structure includes a first cooling substrate, a second cooling substrate, a third cooling substrate, a number of cooling plate P-type semiconductors and a number of cooling plate N-type semiconductors. The first cooling substrate, the second cooling substrate and the third cooling substrate are arranged oppositely in pairs. The first cooling substrate is located below the second cooling substrate, and the third cooling substrate is located above the second cooling substrate. The gaps from the second cooling substrate to the first cooling substrate and the third cooling substrate are equal. The cooling plate P-type semiconductors and the cooling plate N-type semiconductors are arranged in the gaps, and the numbers of the cooling plate P-type semiconductors and the cooling plate N-type semiconductors in the gaps are matched. Cooling plate copper wiring is arranged between each pair of the cooling plate P-type semiconductors and the cooling plate N-type semiconductors; The specimen includes a first PCB board, a second PCB board and a number of solder joints. The first PCB board and the second PCB board are arranged oppositely. The solder joints are arranged between the first PCB board and the second PCB board. The number of the solder joints is arranged in an array. Copper wiring is arranged on both the first PCB board and the second PCB board. The number of the solder joints is connected by copper wiring to form a conducting loop.

2. The micro-solder joint thermal migration device based on the Peltier effect according to claim 1, characterized in that the heating structure and the cooling structure are connected by wires, and the sizes of the heating structure and the cooling structure are matched.

3. The micro-solder joint thermal migration device based on the Peltier effect according to claim 2, wherein a thermal conductive silicone grease is coated on the contact surface between the first heat-generating substrate and the first metal plate, a thermal conductive silicone grease is coated on the contact surface between the third cooling substrate and the second metal plate, and a thermal conductive silicone grease is coated on the contact surfaces between the specimen and the heat-generating structure and the cooling structure.

4. The testing method of the micro-solder-joint thermal migration device based on the Peltier effect as described in claim 3, characterized in that, The steps are as follows: Step 1: Horizontally place the first metal plate and place the heat-generating structure on the first metal plate; Step 2: Place the specimen on the heat-generating structure; Step 3: Place the cooling structure above the specimen, and the cooling structure and the heat-generating structure are placed overlapping and aligned; Step 4: Place the second metal plate above the cooling structure; Step 5: Use four sets of the connecting bolts to connect the first metal plate and the second metal plate, and tighten the nuts; Step 6: Connect the positive and negative poles of the power supply through the copper wiring of the heat-generating plate and connect them to a pair of the P-type semiconductor and the N-type semiconductor of the heat-generating plate in the heat-generating structure, and connect to direct current; Step 7: Start the thermal migration test, and use a thermocouple thermometer to measure the temperatures of the third heat-generating substrate and the first cooling substrate; Step 8: Perform simulation using finite element software; take the measured temperature as the boundary condition of the solder joint of the specimen, and through finite element electro-thermal coupling analysis, the temperature gradient of the solder joint of the specimen can be obtained, so as to obtain reliable and stable micro-solder joint thermal migration data.

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