Method for improving mechanical property stability of thermoelectric refrigerating unit

Abstract

The invention relates to the technical field of thermoelectric refrigerating devices, and discloses a method for improving the mechanical property stability of a thermoelectric refrigerating unit. Uniformly distributed nanoscale particles and a single intermetallic compound layer are doped into a connecting layer between a thermoelectric element and an electrode; the mechanical property attenuation rate of the connecting layer under the high-temperature and high-stress conditions is slowed down, and the service life of the device under the high-temperature and high-cycle-frequency working condition is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoelectric coolers, and in particular to a method for improving the stability of mechanical properties of thermoelectric coolers. Background Art

[0002] Thermoelectric cooling devices are widely used in many fields due to their precise temperature control and fast cooling. In polymerase chain reaction (PCR) equipment, thermoelectric cooling devices can provide rapid temperature changes and precise temperature set points to meet the strict requirements of temperature control in the PCR process.

[0003] Thermoelectric cooling devices consist of copper electrodes on a ceramic substrate and solder joints between semiconductor pairs. Due to the rigid structure, thermal stress is generated inside the device when the module contracts and expands rapidly from repeated cooling and heating cycles. In addition, thermoelectric cooling devices are usually connected in series in the circuit, and the number of solder joints between semiconductor elements and electrodes is twice the number of semiconductor elements. The quality of solder joints directly affects the life of thermoelectric cooling devices.

[0004] At present, a method of embedding a soft thermally conductive "soft layer" between the ceramic substrate and the copper electrode is often used to absorb the mechanical stress caused by temperature cycling to extend the life of the device in temperature cycling applications, such as patent CN217387204U. However, this method can only absorb part of the mechanical stress and cannot improve the problem of fatigue resistance degradation caused by changes in the organizational structure of the connection layer in a high temperature environment. Summary of the invention

[0005] In order to solve the technical problem mentioned in the above background technology that when the device is in service in an environment with high temperature and high cycle frequency, the connection layer structure changes, the mechanical properties decrease, and the fracture causes the device failure, the present invention provides a method for improving the stability of the mechanical properties of a thermoelectric refrigeration device, by selecting a Sn-based solder doped with nano-scale particles as the connection layer material between the semiconductor element and the electrode, and the nano-sized particles are evenly dispersed in the connection layer, so as to achieve the purpose of increasing the mechanical strength of the connection layer and inhibiting the growth of intermetallic compounds, thereby realizing stable operation of the device in a high temperature and high cycle frequency environment.

[0006] The specific technical solution of the present invention is: a method for improving the stability of mechanical properties of a thermoelectric cooler, comprising the following steps: 1) Slicing the semiconductor element, chemically etching it, and then electroplating a metal layer and a welding wetting layer, and cutting the prepared wafer to obtain a thermoelectric element; 2) chemically plating a metal barrier layer on the electrode to obtain an electrode substrate; 3) Nano-scale particles are uniformly added into Sn-based solder to obtain composite solder, wherein the doping amount of nano-scale particles is greater than 0.1 wt %; 4) The thermoelectric element and the electrode substrate are welded with the composite solder to obtain a thermoelectric refrigeration device.

[0007] The present invention provides a method for improving the stability of mechanical properties of a thermoelectric cooler. When the thermoelectric cooler works in a high temperature environment, the thickness of the intermetallic compound of Cu and Sn in the connection layer gradually increases with time. At the same time, as the Cu atoms continue to diffuse, the intermetallic compound gradually changes from Cu6Sn5 to a double-layer intermetallic compound layer of Cu6Sn5 and Cu3Sn, and the mechanical properties are greatly reduced. In addition, under the action of temperature cycles, the device connection layer is subjected to mechanical fatigue and shear stress, and the connection layer is very easy to crack, causing the device to fail in short circuit. The present invention achieves the purpose of increasing the mechanical strength of the connection layer and inhibiting the growth of the intermetallic compound by selecting Sn-based solder doped with nano-scale particles as the connection layer material between the semiconductor element and the electrode, and uniformly dispersing the nano-scale particles in the connection layer.

[0008] Furthermore, in step 3), the nano-scale particles are one of silicon carbide, silicon oxide, and aluminum oxide.

[0009] Furthermore, in step 1), the thickness of the slice is greater than 1 mm.

[0010] Furthermore, in step 1), the reagent used for chemical etching is ferric chloride solution.

[0011] In step 1), the thickness of the electroplated metal layer is greater than 1 μm.

[0012] Furthermore, in step 1), the electroplating layer is one or more of Ni, Co elements and their compounds.

[0013] Furthermore, in step 1), during electroplating, the temperature is 50-60°C.

[0014] Furthermore, in step 2), the chemical plating layer is several or several of the elements and compounds of Ni, Co, and Pd.

[0015] Furthermore, the chemical plating temperature is 60-95° C., the pH is 3-10, and the time is >5 min.

[0016] Furthermore, the material of the solder wetting layer is selected to be Sn or Au.

[0017] Compared with the prior art, the beneficial effects of the present invention are: Under high temperature and high cycle frequency working conditions, the thermoelectric refrigeration device prepared by the present invention improves the stability of the device connection layer, slows down the attenuation rate of the mechanical properties of the connection layer, and increases the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional schematic diagram of the product structure of the thermoelectric refrigeration device of the present invention.

[0019] The reference numerals are: 1) substrate, 2) thermoelectric element. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments.

[0021] Specific examples and comparative examples.

[0022] Example 1 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements The 1.5mm thick thermoelectric semiconductor rod was sliced ​​into 1.3*1.3mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric original Sn layer to improve the welding wettability, as shown in the following figure. Figure 1 The thermoelectric element 2 is shown.

[0023] 2) Preparation of electrode substrate A Ni layer was electrolessly plated on the electrode at 65°C and pH = 4 for 10 min to ensure that the Ni layer completely covered the electrode. Figure 1 The electrode substrate 1 is shown.

[0024] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 0.3wt%.

[0025] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0026] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0027] Comparative Example 1 The difference between this comparative example and Example 1 is that in step 3), non-nanoscale particles are added to the Sn-based solder (that is, non-nanoscale SiC powder is uniformly added to the Sn-based solder), and the rest of the process is the same as that of Example 1, and the specific steps are as follows: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0028] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0029] 3) Preparation of connecting layer SiC non-nanoscale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nanoparticles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nanoscale particles SiC nanoscale particles was 0.3wt%.

[0030] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0031] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0032] Table 1 Effect of particle size of the connecting layer on the final material Particle size Shear strength / kgf Example 1 Nanoscale particles 32 Comparative Example 1 Non-nanoscale particles 15 From the data in Table 1, it can be seen that when non-nanoscale particles are added to the connection layer, the shear strength of the thermoelectric cooling device finally formed is much lower than the thermoelectric cooling device finally made by the connection layer added with nanoscale particles. The reason is speculated to be: the added nanoparticles are evenly dispersed in the solder layer, which, on the one hand, refines the crystal grains and increases the number of grain boundaries, thereby improving the strength; on the other hand, it can inhibit the growth of intermetallic compounds at the welding section, thereby improving the reliability of the solder joint.

[0033] Comparative Example 2 The difference between this comparative example and Example 1 is that in step 3), nanometer-scale particles are not added, and the remaining steps are the same as those in Example 1. The specific steps are as follows: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0034] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0035] 3) Preparation of connecting layer The Sn5Sb solder was directly stirred by mechanical stirring for 15 min to obtain a non-composite solder.

[0036] 4) Welding The thermoelectric element obtained in step 1) and the electrode substrate obtained in step 2) are welded with the non-composite solder obtained in step 3) to obtain a thermoelectric refrigeration device.

[0037] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0038] Comparative Example 3 The difference between this comparative example and Example 1 is that in step 3), the doping amount of the nanoscale particles is 0.1wt%, and the remaining steps are the same as those in Example 1, and the specific steps are as follows: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0039] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0040] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 0.1wt%.

[0041] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0042] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0043] Comparative Example 4 The difference between this comparative example and Example 1 is that in step 3), the doping amount of the nanoscale particles is 5wt%, and the remaining steps are the same as those in Example 1, specifically, the steps are: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0044] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0045] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 5wt%.

[0046] 4) Welding The thermoelectric element obtained in step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric refrigeration device.

[0047] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0048] Table 2 Effect of the amount of nano-scale particles added on the performance of the final thermoelectric cooling device Nano-sized particles incorporated by wt% Shear strength / kgf Example 1 0.3 32 Comparative Example 2 0 27 Comparative Example 3 0.1 27 Comparative Example 4 5 30 From the data in Table 2, we can conclude that when no or less nano-scale particles are added to the solder, the shear strength of the thermoelectric cooling device finally generated will decrease. When the nano-scale particles added to the Sn-based solder are larger, the shear strength of the thermoelectric cooling device finally generated will also decrease. The reason is speculated to be: the added nanoparticles are evenly dispersed in the solder layer. On the one hand, they refine the crystal grains, increase the number of grain boundaries, and play a role in improving the strength. On the other hand, they can inhibit the growth of intermetallic compounds at the welding interface, thereby improving the reliability of the solder joint. When the amount of addition is too much, the agglomeration of nanoparticles weakens the strength of the welding layer; when the amount of addition is too little, the effect of refining the grains is not obvious.

[0049] Example 2 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0050] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0051] 3) Preparation of connecting layer Silicon oxide nano-scale particles are added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-particles are evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles of silicon oxide nano-scale particles is 0.3wt%.

[0052] 4) Welding The thermoelectric element obtained in step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric refrigeration device.

[0053] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0054] Example 3 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements The 1.5mm thick thermoelectric semiconductor rod is sliced ​​into 1.3*1.3mm sized components to be processed. After chemical etching with ferric chloride solution, a Co layer is electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Co layer is 3μm and the temperature is 55°C. Then, a Sn layer is plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0055] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0056] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 2 wt %.

[0057] 4) Welding The thermoelectric element obtained in step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric refrigeration device.

[0058] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0059] Example 4 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 3 μm and the temperature was 60°C. After that, an Au layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer to improve welding wettability.

[0060] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0061] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 0.3wt%.

[0062] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0063] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0064] Example 5 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a Ni layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated Ni layer was 2 μm and the temperature was 50°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0065] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=3 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0066] 3) Preparation of connecting layer Alumina nano-scale particles were added into Sn5Sb solder and stirred for 15 minutes by mechanical stirring to ensure that the nano-particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles of aluminum oxide nano-scale particles was 0.3wt%.

[0067] 4) Welding The thermoelectric element obtained in step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric refrigeration device.

[0068] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0069] Example 6 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.4 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a NiSn layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated NiSn layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer to improve welding wettability.

[0070] 2) Preparation of electrode substrate A Ni layer is chemically plated on the electrode at 65° C. and pH=7 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0071] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 0.3wt%.

[0072] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0073] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0074] Example 7 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a NiCo layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated NiCo layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer that can improve welding wettability.

[0075] 2) Preparation of electrode substrate A Pd layer is chemically plated on the electrode at 60° C. and pH=5 for 10 min to ensure that the Ni layer completely wraps the electrode, thereby obtaining an electrode substrate.

[0076] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 3.1wt%.

[0077] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0078] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0079] Example 8 A method for improving the mechanical performance stability of a thermoelectric refrigeration device comprises the following steps: 1) Preparation of thermoelectric elements Thermoelectric semiconductor rods with a thickness of 1.5 mm were sliced ​​into 1.3*1.3 mm sized components to be processed. After chemical etching with ferric chloride solution, a NiSn layer was electroplated on the processed thermoelectric semiconductor sheet. The thickness of the electroplated NiSn layer was 3 μm and the temperature was 55°C. After that, a Sn layer was plated on the outside of the Ni layer to obtain a thermoelectric Sn layer to improve welding wettability.

[0080] 2) Preparation of electrode substrate A Co layer was chemically plated on the electrode at 65° C. and pH=4 for 10 min to ensure that the Ni layer completely wrapped the electrode, thereby obtaining an electrode substrate.

[0081] 3) Preparation of connecting layer SiC nano-scale particles were added into Sn5Sb solder and stirred by mechanical stirring for 15 minutes to ensure that the nano-scale particles were evenly dispersed in the solder to obtain a composite solder, wherein the doping amount of the nano-scale particles SiC nano-scale particles was 0.5wt%.

[0082] 4) The thermoelectric element obtained in welding step 1) and the electrode substrate obtained in step 2) are welded with the composite solder obtained in step 3) to obtain a thermoelectric cooling device.

[0083] 5) Detection The mechanical properties of the thermoelectric cooling device prepared in step 4) are tested.

[0084] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0085] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for improving the stability of mechanical properties of a thermoelectric cooler, characterized in that: include: 1) Slicing the semiconductor element, chemically etching it, and then electroplating the metal layer and the welding wetting layer, and cutting the prepared wafer to obtain the thermoelectric element; 2) chemically plating a metal barrier layer on the electrode to obtain an electrode substrate; 3) Nano-scale particles are uniformly added into Sn-based solder to obtain composite solder, and the doping amount of nano-scale particles is greater than 0.1wt%; 4) The thermoelectric element and the electrode substrate are welded with a composite solder to obtain a thermoelectric cooling device.

2. A method for improving the stability of mechanical properties of a thermoelectric cooler according to claim 1, characterized in that: In step 3), the nano-scale particles are one of silicon carbide, silicon oxide, and aluminum oxide.

3. The method for improving the mechanical performance stability of a thermoelectric cooler according to claim 1, characterized in that: In step 1), the thickness of the slice is > 1 mm.

4. A method for improving the stability of mechanical properties of a thermoelectric cooler according to claim 1 or 3, characterized in that: The reagent used for chemical etching is ferric chloride solution.

5. A method for improving the stability of mechanical properties of a thermoelectric cooler according to claim 1 or 3, characterized in that: In step 1), the thickness of the electroplated metal layer is greater than 1 μm.

6. The method for improving the stability of mechanical properties of a thermoelectric cooler according to claim 1, characterized in that: In step 1), the electroplating layer is one or more of Ni, Co, NiSn and NiCo.

7. The method for improving the mechanical performance stability of a thermoelectric cooler according to claim 1, characterized in that: In step 1), during electroplating, the temperature is 50~60℃.

8. The method for improving the mechanical performance stability of a thermoelectric cooler according to claim 1, characterized in that: In step 2), the chemical plating layer is one or more of the elements of Ni, Co, Pd and Ni-based compounds.

9. The method for improving the mechanical performance stability of a thermoelectric cooler according to claim 1, characterized in that: The chemical plating temperature is 60~95℃, the pH is 3~10, and the time is >5min.

10. The method for improving the stability of mechanical properties of a thermoelectric cooler according to claim 1, characterized in that: The material of the solder wetting layer should be Sn or Au.

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