A thin-film thermoelectric cooler and a method for preparing the thin-film thermoelectric cooler.

Abstract

This application provides a thin-film thermoelectric cooler. It includes a substrate, P-type thermoelectric units, N-type thermoelectric units, a first electrode, and a second electrode. The substrate has a hollowed-out area. On one side of the substrate, perpendicular to a direction, P-type and N-type thermoelectric units are stacked to form thermocouple pairs. The cold ends of the thermocouple pairs are connected through the first electrode. The hot ends of the thermocouple pairs are connected to the second electrode. The cold ends of multiple thermocouple pairs are concentrated in one area of ​​the thin-film thermoelectric cooler, forming a cold load thin-film region. The cold ends of the multiple thermocouple pairs and the portions of the thermocouple arms connected to the cold ends are located in the hollowed-out area of ​​the substrate. By combining the stacked thermocouple pair layout, substrate hollowing technology, and distributing the cold ends in a relatively concentrated area, the efficiency of thermoelectric conversion is improved. This enhances the cooling capacity of horizontal thin-film thermoelectric devices and achieves efficient heat dissipation.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a thin-film thermoelectric cooler and a method for preparing a thin-film thermoelectric cooler. Background Technology

[0002] As microelectronic and optoelectronic devices evolve towards smaller sizes, higher integration, and lower power consumption, new challenges arise for the thermal management of miniature, low-power devices such as photoelectric emitters. To effectively address the heat dissipation issues of these devices, thin-film thermoelectric devices have attracted widespread attention due to their lightweight, high efficiency, and integrability. Based on their structural characteristics, thin-film thermoelectric devices are mainly classified into two types: horizontal and vertical.

[0003] In horizontal thin-film thermoelectric devices, the thermocouple arms extend horizontally, with the cold and hot ends of the arms located on opposite sides of the thin film. Because the thermocouple arms are tightly attached to the substrate, and the cold and hot ends are on opposite sides, the underlying substrate becomes one of the main heat conduction paths, introducing a thermal bypass problem. This thermal bypass significantly weakens the actual cooling effect of the thermoelectric cooling device and reduces its output power.

[0004] Therefore, improving the cooling capacity of horizontal thin-film thermoelectric devices and achieving efficient heat dissipation is a key issue that urgently needs to be addressed. Summary of the Invention

[0005] In view of this, this application provides a thin-film thermoelectric cooler and a method for preparing the thin-film thermoelectric cooler, aiming to improve the cooling capacity of horizontal thin-film thermoelectric devices and achieve efficient heat dissipation.

[0006] In a first aspect, this application provides a thin-film thermoelectric cooler, including a substrate, a P-type thermoelectric unit, an N-type thermoelectric unit, a first electrode and a second electrode, wherein the substrate is provided with a hollow area;

[0007] On one side of the substrate, along a direction perpendicular to the substrate, the P-type thermoelectric unit and the N-type thermoelectric unit are stacked to form a thermocouple pair; the cold end of the thermocouple pair is connected through the first electrode; the hot end of the thermocouple pair is connected to the second electrode.

[0008] The cold ends of multiple thermocouple pairs are concentrated in one area of ​​the thin-film thermoelectric cooler to form a cold load thin-film region, and the cold ends of multiple thermocouple pairs and the part of the thermocouple arm connected to the cold ends are located in the hollow area of ​​the substrate.

[0009] Optionally, the substrate has a hollow area including an annular hollow section; the annular hollow section has multiple concentric annular slits, multiple radially distributed strip slits, or a combination of multiple concentric annular slits and multiple radially distributed strip slits.

[0010] Optionally, the cold load thin film region is located at the center of the thin film thermoelectric cooler.

[0011] Optionally, the cold-load film region includes one of a rectangle, a circle, and a complex polygon.

[0012] Optionally, the materials of the P-type thermoelectric unit and the thermoelectric materials of the N-type thermoelectric unit are any one or more of the following: bismuth telluride-based binary or ternary materials, antimony telluride-based binary or ternary materials, lead telluride-based binary or ternary materials, tin selenide-based binary or ternary materials, magnesium-based binary or ternary materials, telluride-based binary or ternary materials, tin-based binary or ternary materials, germanium-silicon alloy materials, semi-Hasler alloys, graphene, squartzite, or filled squartzite materials.

[0013] Secondly, embodiments of this application provide a method for preparing a thin-film thermoelectric cooler, the method comprising:

[0014] Provide a base;

[0015] A multilayer thermoelectric thin film is obtained by sequentially depositing a first insulating layer, a P-type thermoelectric unit layer, a second insulating layer, and an N-type thermoelectric unit layer on one side of the substrate along a direction perpendicular to the substrate.

[0016] Thermocouple arms are fabricated on the multilayer thermoelectric thin film using an etching process to obtain multilayer thermocouple pairs and a cold load thin film region; one end of each of the multiple thermocouple pairs is concentrated in one region of the thin film thermoelectric cooler.

[0017] A vacuum coating method is used to connect one end of a thermocouple pair concentrated in a region of the thin-film thermoelectric cooler through a first electrode to form a cold junction; and the other end of the thermocouple pair is connected to a second electrode to form a hot junction.

[0018] A portion of the substrate is removed using an etchant, creating a hollowed-out area on the substrate.

[0019] Optionally, the step of fabricating thermocouple arms on the multilayer thermoelectric thin film using an etching process to obtain a multilayer thermocouple pair includes:

[0020] Photoresist is coated on the multilayer thermoelectric thin film, and a pattern is formed on the photoresist with one end of multiple thermocouple pairs concentrated in one area of ​​the thin film thermoelectric cooler by photolithography.

[0021] Based on the pattern, multiple thermocouple arms are etched on the multilayer thermoelectric thin film using photolithography to obtain a multilayer thermocouple pair.

[0022] Optionally, the cold-load film region is prepared in the following manner:

[0023] A third insulating layer is deposited on the thermocouple pair of the multilayer structure;

[0024] The third insulating layer is patterned using a photolithography etching process to obtain a cold-load thin film region.

[0025] Optionally, the deposition method is any one or more of chemical vapor deposition, physical vapor deposition, molecular beam epitaxy, sol-gel method, pulsed laser deposition, and atomic layer deposition.

[0026] Optionally, the corrosive agent includes any one or more of tetramethylammonium hydroxide, ethylenediaminepyrrolidone, a mixed solution of nitric acid and hydrogen peroxide, a mixed solution of sulfuric acid and hydrogen peroxide, potassium hydroxide, sodium hydroxide, and xenon fluoride.

[0027] This application provides a thin-film thermoelectric cooler. It includes a substrate, P-type thermoelectric units, N-type thermoelectric units, a first electrode, and a second electrode. The substrate has a perforated area. On one side of the substrate, perpendicular to the substrate direction, P-type and N-type thermoelectric units are stacked to form thermocouple pairs. The cold ends of the thermocouple pairs are connected through the first electrode. The hot ends of the thermocouple pairs are connected to the second electrode. The cold ends of multiple thermocouple pairs are concentrated in one area of ​​the thin-film thermoelectric cooler, forming a cold load thin-film region. The cold ends of the multiple thermocouple pairs and the portions of the thermocouple arms connected to the cold ends are located in the perforated area of ​​the substrate. By stacking the P-type and N-type thermoelectric units instead of arranging them side-by-side, the number of thermocouple pairs per unit area is significantly increased. Furthermore, by providing a perforated area on the substrate, some thermocouple arms and cold ends are prevented from contacting the substrate to eliminate thermal bypass. Simultaneously, the cold ends are distributed in a relatively concentrated area. Through the synergistic effect of the cold ends of multiple thermocouple pairs, heat is effectively absorbed from the surrounding environment, thereby improving the efficiency of thermoelectric conversion. This can improve the cooling capacity of horizontal thin-film thermoelectric devices and achieve efficient heat dissipation. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings used in the description of the embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a thin-film thermoelectric cooler in the related technology;

[0030] Figure 2 A schematic diagram of another thin-film thermoelectric cooler structure provided in the embodiments of this application;

[0031] Figure 3 is Figure 2 a schematic cross-sectional view along the A-A' direction;

[0032] Figures 4a-4d a schematic diagram of the substrate with a hollow structure provided by an embodiment of the present application;

[0033] Figures 5a-5c a schematic diagram of the cold-end concentration provided by an embodiment of the present application;

[0034] Figures 6a-6c a schematic diagram of the cold-load thin-film region provided by an embodiment of the present application;

[0035] Figure 7 a flowchart of a method for fabricating a thin-film thermoelectric cooler provided by an embodiment of the present application;

[0036] Figure 8 a schematic structural diagram of the fabrication process of a thin-film thermoelectric cooler provided by an embodiment of the present application;

[0037] Figure 9 a schematic structural diagram of a "hui"-character-shaped horizontal thin-film thermoelectric cooling device and its thermocouple arms provided by an embodiment of the present application;

[0038] Figure 10 a schematic diagram of the temperature distribution of a "hui"-character-shaped horizontal thin-film thermoelectric cooling device provided by an embodiment of the present application;<00, "hui"-character-shaped horizontal thin-film thermoelectric cooling device provided by an embodiment of the present application;

[0039] Among them, 1 is the substrate; 11 is the annular hollow section; 12 is the cavity; 101 is the annular gap; 102 is the strip-shaped gap; 2 is the thermocouple arm; 21 is the P-type thermoelectric unit; 22 is the N-type thermoelectric unit; 23 is the silicon oxide insulating layer; 24 is the silicon nitride insulating layer; 3 is the metal electrode; 4 is the cold-load thin-film region. Detailed implementation manners

[0040] Figure 1 is a schematic structural diagram of a thin-film thermoelectric cooler in the related art. As shown in Figure 1 the figure, the thermocouple arms of the horizontal thin-film thermoelectric device are parallel to the substrate. Therefore, its fabrication process is relatively simple and compatible with the current mature integrated circuit fabrication process. However, the thermal conductivity of the substrate material may cause thermal bypass, that is, heat is transferred from the hot end to the cold end through the substrate, offsetting the cooling capacity of the cold end, which will reduce the thermoelectric conversion efficiency. In addition, if the substrate is completely removed to eliminate thermal bypass, then only relying on the thermocouple arms to support the cold end may cause mechanical stability problems, especially in large devices.

[0041] In view of this, this application provides a thin-film thermoelectric cooler. It includes a substrate, P-type thermoelectric units, N-type thermoelectric units, a first electrode, and a second electrode. The substrate has a perforated area. On one side of the substrate, perpendicular to the substrate direction, P-type and N-type thermoelectric units are stacked to form thermocouple pairs. The cold ends of the thermocouple pairs are connected through the first electrode. The hot ends of the thermocouple pairs are connected to the second electrode. The cold ends of multiple thermocouple pairs are concentrated in one area of ​​the thin-film thermoelectric cooler, forming a cold load thin-film region. The cold ends of multiple thermocouple pairs and the portions of the thermocouple arms connected to the cold ends are located in the perforated area of ​​the substrate. By stacking the P-type and N-type thermoelectric units instead of arranging them side-by-side, the number of thermocouple pairs per unit area is significantly increased. Furthermore, by providing a perforated area on the substrate, some thermocouple arms and cold ends do not contact the substrate to eliminate thermal bypass. Simultaneously, the cold ends are distributed in a relatively concentrated area. Through the synergistic effect of the cold ends of multiple thermocouple pairs, heat is effectively absorbed from the surrounding environment, thereby improving the efficiency of thermoelectric conversion. This can improve the cooling capacity of horizontal thin-film thermoelectric devices and achieve efficient heat dissipation.

[0042] To facilitate understanding of the following embodiments of this application, the principle of the thin-film thermoelectric cooler will now be explained.

[0043] A thermoelectric cooler is a cooling device that utilizes the Peltier effect to achieve localized thermal management of an instrument. The Peltier effect, also known as the Peltier effect, is a thermoelectric phenomenon that refers to the phenomenon of heat absorption or release at the junction when an electric current passes through a thermocouple composed of two different conductors or semiconductors.

[0044] The Peltier effect comprises two main aspects: The Peltier effect: When an electric current passes through a thermocouple, heat is released at the end where the current enters (usually called the hot junction) and absorbed at the end where the current leaves (usually called the cold junction). This means that a temperature difference can be created between the two junctions when current passes through the thermocouple, thus achieving a cooling effect, i.e., thermoelectric cooling. The Seebeck effect: This is the reverse process of the Peltier effect. When a temperature difference exists across the thermocouple, an electric current is generated. This process is actually thermoelectric power generation, converting heat energy into electrical energy.

[0045] The Peltier effect has wide applications in thermoelectric coolers and thermoelectric generators. Thermoelectric coolers (TECs) utilize the positive Peltier effect to achieve cooling without mechanical moving parts, making them suitable for small systems requiring precise temperature control, such as laser diode cooling, microprocessor cooling, and portable refrigerators. Thermoelectric generators (TEGs), on the other hand, utilize the inverse Peltier effect to directly convert heat energy into electrical energy, and are commonly found in space probes, thermopile reactors, and some wearable devices.

[0046] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their illustration to simplify the drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] Figure 2 This is a schematic diagram of a thin-film thermoelectric cooler structure provided in an embodiment of this application. Figure 3 yes Figure 2 A schematic diagram of a cross-section along the A-A' direction, see [reference]. Figure 2 and Figure 3 The thin-film thermoelectric cooler provided in this application includes a substrate 1, a P-type thermoelectric unit 21, an N-type thermoelectric unit 22, an insulating layer 23, a first electrode 31 and a second electrode 32, and the substrate is provided with a hollow area 12.

[0048] On one side of the substrate 1, along a direction perpendicular to the substrate 1, P-type thermoelectric units 21 and N-type thermoelectric units 22 are stacked to form a thermocouple pair 2; the cold end of the thermocouple pair is connected through the first electrode; the hot end of the thermocouple pair is connected to the second electrode; the cold end of the thermocouple pair 2 is connected through the first electrode 31; the hot end of the thermocouple pair is connected to the second electrode 32.

[0049] The cold ends of multiple thermocouple pairs 1 are concentrated in one area of ​​the thin-film thermoelectric cooler, forming a cold load thin-film region 4, and the cold ends of multiple thermocouple pairs 2 and the part of the thermocouple arm connected to the cold ends are located in the hollow region 12 of the substrate 1.

[0050] Specifically, such as Figure 2 In the illustrated embodiment, the thin-film thermoelectric cooler includes a substrate 1 and 16 pairs of thermocouples 2. The substrate 1 is typically made of a material with good thermal conductivity and mechanical stability, such as ceramics, metals, or polymer composites. The substrate serves as a support structure for the thermocouple pairs while effectively conducting heat. At least one pair of thermocouples means that multiple pairs may be included to increase the cooling effect. Each thermocouple pair consists of two main parts forming a thermoelectric unit made of N-type and P-type semiconductor materials (…). Figure 2(Not shown in the image), they have different carrier types (electrons or holes) and different Seebeck coefficients. The P-type thermoelectric units and N-type thermoelectric units are connected by conductive material 3 (such as the first electrode 31 and the second electrode 32) to form an electrically series but thermally parallel structure so as to generate a temperature difference effect when current passes through. The conductive material can be a metal wire or a conductive thin film, which is not limited in this application.

[0051] When a direct current flows through a series circuit, electrons flow from the N-type thermoelectric unit to the P-type thermoelectric unit, while holes flow from the P-type thermoelectric unit to the N-type thermoelectric unit. Because the N-type and P-type thermoelectric units have different Seebeck coefficients (i.e., the ability of different materials to generate electromotive force when the temperature changes), a temperature difference is generated at the junction of the N-type and P-type thermoelectric units when the current flows through them. Specifically, the end where the current flows in (usually called the hot end) releases heat, causing its temperature to rise; while the end where the current flows out (usually called the cold end) absorbs heat, causing its temperature to drop.

[0052] Specifically, the substrate 1 is also hollowed out to form one or more cavities 12. Figure 1 (An example of a cavity is shown below). This hollow design means that the base material in the cavity 12 region is removed, and the resulting cavity can provide space for part of the thermocouple arm and the cold end of the thermocouple arm, so that it is suspended to eliminate the effect of thermal bypass.

[0053] like Figure 3 As shown, thermocouple pair 2 includes a P-type thermoelectric unit 21 and an N-type thermoelectric unit 22, which are stacked in a direction perpendicular to the substrate 1. For example, the N-type thermoelectric unit is an electronic semiconductor, with electrons as its primary charge carriers; while the P-type thermoelectric unit is a hole-type semiconductor, with holes as its primary charge carriers. The N-type and P-type thermoelectric units are connected at both ends by a conductive material (such as a metal wire or metal film) to form an electrically connected series structure, but the thermocouple pairs are thermally connected in parallel. The hot ends of the P-type thermoelectric unit 21 and the N-type thermoelectric unit 22 are connected to the remaining portion of the hollowed-out substrate, while the cold ends are suspended in the cavity of the hollowed-out area. That is, the cold ends do not directly contact the substrate but are supported above the cavity by the thermocouple arms themselves.

[0054] In this embodiment, the hollow substrate design reduces the impact of the substrate material's thermal conductivity on thermoelectric performance. Traditionally, substrate materials may cause heat to flow directly from the hot end to the cold end, rather than through thermocouple arms for thermoelectric conversion. The hollow substrate can significantly reduce this thermal bypass, thereby improving thermoelectric conversion efficiency.

[0055] Because the cold end is suspended, it provides better thermal insulation from the substrate, allowing it to absorb heat more effectively without being negatively affected by the substrate's thermal conductivity. This improves cooling efficiency, especially for microchips requiring localized, high-efficiency cooling. Furthermore, the suspended cold end design allows for a larger temperature difference between the hot and cold ends of the thermocouple arm, as the cold end does not receive additional heat from the substrate. This larger temperature difference enhances the thermoelectric performance of the thermocouple arm, thereby improving the overall cooling capacity and efficiency of the thin-film thermoelectric cooler.

[0056] The cavity in the hollow substrate provides a more direct path for heat flow, and the heat transfer from the hot end to the cold end is not affected by the substrate material. This helps to optimize the heat flow path and reduce energy loss. Furthermore, the hollow design reduces the amount of material used in the substrate, making the entire thin-film thermoelectric cooler thinner and lighter, which is especially important for mobile devices or portable applications that require lightweight and small size.

[0057] Based on the above embodiments, considering that horizontally arranged thin-film thermoelectric coolers in related technologies generally adopt an arrangement with one side being the hot end and the other side being the cold end, but this arrangement makes the cold ends relatively dispersed, thereby reducing the cooling effect, in this embodiment, the cold ends of multiple thermocouple pairs 2 are further concentrated in a specific area of ​​the thin-film cooler to form a cold load thin-film region 4.

[0058] In an optional embodiment, the materials of the P-type thermoelectric unit and the thermoelectric materials of the N-type thermoelectric unit are any one or more of the following: bismuth telluride (Bi2Te3)-based binary or ternary materials, antimony telluride (Sb2Te3)-based binary or ternary materials, lead telluride (Pb2Te3)-based binary or ternary materials, tin selenide (SnSe)-based binary or ternary materials, magnesium (Mg)-based binary or ternary materials, telluride (Te)-based binary or ternary materials, tin (Sn)-based binary or ternary materials, germanium-silicon (SiGe) alloy materials, semi-Hassler alloys, graphene, cobaltite, or filled cobaltite materials.

[0059] Bismuth telluride (Bi₂Te₃) is a compound composed of bismuth and tellurium, possessing excellent thermoelectric properties and commonly used in thermoelectric materials and infrared detection. Its performance can be further optimized when combined with other elements to form binary or ternary materials. Antimony telluride (Sb₂Te₃) is also a compound composed of antimony and tellurium, exhibiting topological insulator properties and good thermoelectric performance. Lead telluride (PbTe) is a mid-temperature thermoelectric material with excellent thermoelectric properties. Binary or ternary materials formed by combining it with other elements may achieve even higher thermoelectric conversion efficiencies.

[0060] Tin selenide (SnSe) is a semiconductor material with high thermoelectric properties, especially exhibiting excellent thermoelectric performance at low temperatures. Combining it with other elements may further enhance its properties. Magnesium-based materials refer to alloys or compounds with magnesium as the main element. When magnesium is combined with other metallic elements to form binary or ternary alloys, it may possess excellent mechanical properties, corrosion resistance, or lightweight and high strength characteristics. Tellurium-based materials refer to compounds or alloys with tellurium as the main element. Tin-based materials refer to alloys or compounds with tin as the main element. Silicon-germanium alloy (SiGe) is an alloy material composed of silicon and germanium, possessing excellent semiconductor properties.

[0061] Half-Heusler alloys are compounds composed of three elements with unique crystal structures and electronic properties, exhibiting distinctive band structures and thermoelectric performance. Graphene is a two-dimensional material composed of carbon atoms, possessing extremely high electrical and thermal conductivity and mechanical strength. Cobaltite is a class of compounds with special crystal structures, commonly used in thermoelectric materials. Filled cobaltite refers to materials in which other elements or compounds are filled into the crystal structure of cobaltite to improve its thermoelectric properties.

[0062] In the above embodiments, by stacking P-type and N-type thermoelectric units instead of arranging them side-by-side, the number of thermocouple pairs per unit area is significantly increased. Furthermore, by creating a perforated area on the substrate, some thermocouple arms and cold ends are prevented from contacting the substrate to eliminate thermal bypass. Simultaneously, the cold ends are distributed in a relatively concentrated area. Through the synergistic effect of multiple thermocouple pairs and their cold ends, heat is effectively absorbed from the surrounding environment, thereby improving the efficiency of thermoelectric conversion. In this way, the cooling capacity of horizontal thin-film thermoelectric devices can be improved, achieving highly efficient heat dissipation.

[0063] Optionally, there are several possible ways to implement the hollowed-out area of ​​the base. Figures 4a-4d A schematic diagram of the substrate with a hollowed-out design provided for an embodiment of this application (side away from the thermocouple arm, the thermocouple arm is not shown). Combined with... Figures 4a-4d As shown, the base hollowing-out setting may include an annular hollowing-out segment 11 ( Figure 4a ); Multiple concentric annular slits 101 are opened on the annular hollow section 11. Figure 4b ), multiple radially distributed strip-shaped slits 102 ( Figure 4c () or a combination of multiple concentric annular slits 101 and multiple radially distributed strip slits 102 ( Figure 4d ).

[0064] In this embodiment, the annular hollow segment refers to one or more annular void regions formed on the substrate. These regions can be complete annular or partial annular. The annular hollow segment provides a larger heat dissipation area for the hot end of the thermoelectric unit, facilitating the rapid transfer of heat from the hot end to the external environment. Simultaneously, it may also serve as a supporting component for the internal structure of the device, enhancing the overall stability of the device. It should be noted that the annular shape described in this embodiment can include circles, rectangles, etc., and can be specifically designed according to the requirements of the thin-film thermoelectric cooler.

[0065] Specifically, various gaps can be created in the annular hollow section to further increase the heat dissipation area and optimize the heat dissipation effect:

[0066] See Figure 4b As shown, these gaps extend outwards layer by layer with varying radii from the center of the annular perforated section. They can be continuous or discontinuous, depending on manufacturing capabilities and design requirements. The annular gaps increase the heat dissipation area and guide heat flow along the gap direction, thereby improving heat dissipation efficiency.

[0067] See Figure 4c As shown, the slits 102 originate from the center of the annular perforated section and extend outwards radially. They can be straight or curved, depending on the design objectives. These strip-shaped slits also increase the heat dissipation area, and because they are radially distributed, they can more effectively transfer heat from the central area to the edge area, and then dissipate it into the external environment.

[0068] See Figure 4d As shown, a combination of multiple concentric annular slits and multiple radially distributed strip slits can also be used. This combined design integrates the advantages of both, achieving more efficient heat dissipation. By rationally arranging the position and size of the slits, the path and distribution of heat flow can be further optimized, improving heat dissipation efficiency and reducing thermal stress.

[0069] In this embodiment, by increasing the heat dissipation area and altering the heat flow path, this slot design significantly improves the heat dissipation performance of the thermoelectric cooling device. A well-designed slot can reduce thermal stress generated during operation, improving device reliability and lifespan. Although the cold end is suspended, the designed thermocouple arm and substrate structure ensure sufficient mechanical stability, preventing deformation or damage during operation.

[0070] In one optional embodiment, the cold ends of multiple thermocouple pairs are concentrated in one region of the thin-film thermoelectric cooler, forming a cold load thin-film region. There are several possible implementations for this. In this embodiment, the cold ends of the P-type and N-type thermoelectric units are concentrated at the center of the thin-film thermoelectric cooler.

[0071] Specifically, concentrating the cold end at the center position makes the cooling effect more focused and efficient. In the thermoelectric cooling process, the cold end is the part that absorbs heat and produces a cooling effect. Because the cold end is concentrated at the center position, it can absorb heat through a relatively uniform heat conduction path, making the heat absorption effect of the cold end of the same thin-film thermoelectric cooler more uniform. This reduces the problem of local overheating or insufficient cooling caused by uneven distribution of the cold end, and makes the temperature distribution of the entire cooling surface more uniform. This facilitates the faster transfer of heat from the surrounding environment to the cooler and its dissipation, thereby improving the overall cooling efficiency.

[0072] Furthermore, the centralized cold-end design contributes to the compactness of the cooler's structure. This layout reduces the required space, making it easier to integrate thin-film thermoelectric coolers into small devices or within limited spaces. By designing appropriate heat conduction paths and heat dissipation structures, the heat absorbed at the cold end can be transferred and dissipated into the environment more effectively, thereby maintaining the stable operation of the cooler.

[0073] Centralizing the cold end reduces heat loss due to conduction or radiation. Any unnecessary heat loss during refrigeration reduces efficiency. Centralizing the cold end makes heat flow easier to control, minimizing these losses. This design also allows for modular manufacturing and assembly. The refrigerator can be designed as a series of thermoelectric unit modules, each containing both a cold and a hot end, which can be assembled at a central location to form a highly efficient refrigeration system.

[0074] In one alternative embodiment, there are several possible ways to centrally position the cold ends of the P-type thermoelectric unit 21 and the N-type thermoelectric unit 22 at the center of the thin-film thermoelectric cooler.

[0075] Central Island Design: A central island-shaped structure is designed on the substrate of the thin-film thermoelectric cooler, slightly higher than the surrounding area. The cold ends of the P-type and N-type thermoelectric units are directly fixed to this central island, forming a concentrated cold end region. This design is simple in structure and easy to manufacture and assemble. The concentrated cold end facilitates thermal management and reduces heat loss.

[0076] Embedded cold-end design: One or more central grooves or through-holes are pre-machined into the substrate of the thin-film thermoelectric cooler to serve as receiving spaces for the cold end. The cold ends of P-type and N-type thermoelectric units are embedded in these grooves or through-holes and connected to the substrate by appropriate fixing methods (such as welding, bonding, etc.). The large thermal contact area between the cold end and the substrate facilitates rapid heat transfer. The embedded design reduces heat loss at the cold end and improves cooling efficiency.

[0077] Multi-layer stacked design: This design employs a multi-layer thin-film structure, alternatingly stacking thermoelectric units and insulating layers. During stacking, the cold ends of the first and second thermoelectric units are aligned and concentrated at the center, connected by wires or conductive layers. This method results in a compact structure and achieves high thermoelectric conversion efficiency. The multi-layer stacked design also helps reduce heat loss and improve cooling performance.

[0078] Thermal bridge design: A thermal bridge structure is constructed on the substrate of the thin-film thermoelectric cooler to connect the cold ends of the first and second thermoelectric units, and is centrally located. The thermal bridge material should have good thermal conductivity to ensure heat transfer between the cold ends. Thermal bridge design enables rapid thermal equilibrium at the cold ends, improving cooling efficiency. Simultaneously, it can optimize thermal management strategies and reduce heat loss.

[0079] Flexible connection design: Flexible materials (such as conductive adhesive, metal foil, etc.) are used to connect the cold ends of the first and second thermoelectric units, and they are concentrated at the center of the thin-film thermoelectric cooler using appropriate fixing methods. This flexible connection design can adapt to substrates of different shapes and sizes. It offers excellent adaptability and flexibility, accommodating various complex manufacturing processes and working environments. Simultaneously, it reduces heat loss caused by mechanical stress.

[0080] Figures 5a-5c This is a schematic diagram of cold junction concentration provided in an embodiment of this application, combined with... Figures 5a-5c As shown, the cold ends of the P-type thermoelectric unit and the N-type thermoelectric unit are concentrated at the center of the thin-film thermoelectric cooler, including: thermocouple pairs 2 composed of stacked P-type thermoelectric units 21 and N-type thermoelectric units 22 arranged around the central cold load thin film region 4; the cold load thin film region 4 is located at the center of the thin-film thermoelectric cooler.

[0081] Specifically, Figure 5a The thermocouple arms are arranged in a ring around the cold load film area 4. This ring arrangement allows more thermocouple arms to be connected to the cold load film area 4, thereby improving refrigeration efficiency.

[0082] Figure 5b The thermocouple arms are distributed around the cold load film region 4, for example. Figure 5b The number and length of thermocouple arms in each direction are equal. In this embodiment, a U-shaped thin-film thermoelectric cooler is formed. The equal number and length of thermocouple arms make the structure more stable, and this regular pattern is more convenient for fabrication and mass production.

[0083] Figure 5c The thermocouple arms are distributed around the cold load film region 4, for example. Figure 5cThe number and length of thermocouple arms in each direction are not equal. In some applications, irregular devices such as rectangles are required. However, rectangular devices cause the thermocouple arms on the long side to bear greater pressure. In view of this, the thermocouple arms distributed in this embodiment are wider along the long side to ensure sufficient support for the cold end, and the number of thermocouple arms is increased along the short side to improve the cooling effect.

[0084] In an optional embodiment, the cold-load film region includes one of a rectangle, a circle, and a complex polygon. Figures 6a-6c This is a schematic diagram of the cold load film region provided in an embodiment of this application. (In conjunction with...) Figures 6a to 6c As shown, rectangular cold load film regions are easier to fabricate. Circular cold load film regions allow for more uniform heat distribution at the cold end. Polygonal designs offer the possibility of subsequently assembling multiple thin-film thermoelectric coolers.

[0085] The thin-film thermoelectric cooler provided in the embodiments of this application has been introduced above. The preparation method of the thin-film thermoelectric cooler will be described in the following example with reference to specific application scenarios.

[0086] Figure 7 This is a flowchart illustrating a method for fabricating a thin-film thermoelectric cooler, as provided in an embodiment of this application. Figure 7 As shown, the method for fabricating a thin-film thermoelectric cooler provided in this application embodiment may include:

[0087] S701 provides the substrate.

[0088] In this embodiment, a suitable substrate material is selected, such as silicon, sapphire, or ceramic, which typically have good thermal stability and mechanical strength, making them suitable as a support for thermoelectric thin films.

[0089] For example, Figure 8 This is a schematic diagram illustrating the fabrication process of a thin-film thermoelectric cooler, provided as an embodiment of this application. (Combined with...) Figure 8 As shown in (a), prepare a double-sided polished silicon substrate with crystal orientation... <100> Thickness 350μm.

[0090] S702, a multilayer thermoelectric thin film is obtained by sequentially depositing a first insulating layer, a P-type thermoelectric unit layer, a second insulating layer and an N-type thermoelectric unit layer on one side of the substrate along a direction perpendicular to the substrate.

[0091] On a substrate, a first insulating layer, a P-type thermoelectric unit layer, a second insulating layer, and an N-type thermoelectric unit layer are sequentially deposited using techniques such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). This step constructs the foundation of the thermoelectric thin film, where the insulating layer isolates different types of thermoelectric materials to prevent short circuits. Silicon nitride is used as the insulating layer material; however, in practical applications, other types of insulating materials can be selected, and this application does not impose any limitations on this comparison.

[0092] See Figure 8 (b) The P-type thermoelectric unit and the N-type thermoelectric unit are made of bismuth telluride material, and the insulating layer is made of silicon nitride material. A silicon oxide film (0.5 μm), bismuth telluride (P-type 1.2 μm), silicon oxide film (0.5 μm), and bismuth telluride (N-type 1.2 μm) are sequentially deposited on the silicon substrate by chemical vapor deposition (LPCVD).

[0093] In one alternative embodiment, there are a variety of possible deposition methods for preparing multilayer structures, including chemical vapor deposition (LPCVD), physical vapor deposition (PVD), molecular beam epitaxy (MBE), sol-gel method, pulsed laser deposition (PLD), and atomic layer deposition (ALD).

[0094] Chemical vapor deposition involves introducing a gaseous precursor containing the elements required for the thin film into a high-temperature reaction chamber, where the precursor molecules undergo a chemical reaction on the substrate surface to generate the desired solid thin film.

[0095] Physical vapor deposition (PVD) is a technique that transforms a material from a solid state to a gaseous state through physical processes (such as evaporation and sputtering) and deposits it as a film on a substrate. For silicon oxide thin films, sputtering methods (such as radio frequency sputtering and magnetron sputtering) can be used for deposition.

[0096] Molecular beam epitaxy (MBE) is a technique that uses ultra-high vacuum conditions to directly spray thermally evaporated atomic or molecular beams onto a substrate, precisely controlling the growth rate, thickness, and composition of thin films by controlling parameters such as beam intensity and substrate temperature. MBE technology is suitable for preparing multilayer structures and materials with complex compositions as described in this embodiment.

[0097] The sol-gel method is a method for preparing thin films through the gelation process of a sol. First, the desired metal alkoxide or inorganic salt is dissolved in a solvent to form a homogeneous sol; then, the sol is gradually gelled through heating, stirring, and other treatments; finally, the gelled film is coated onto a substrate and heat-treated to form a dense film.

[0098] Pulsed laser deposition (PLD) is a technique that uses a high-energy pulsed laser beam to bombard the surface of a target material, causing atoms or molecules on the target surface to evaporate and deposit onto a substrate to form a thin film. PLD technology can produce high-quality, high-purity thin films and can achieve the co-deposition of multiple elements.

[0099] Atomic layer deposition (ALD) is a thin film deposition technique based on surface chemical reactions. By alternately introducing reactive precursors and inert gases, a self-limiting reaction occurs on the substrate surface, depositing thin films layer by layer. ALD technology allows for precise control of film thickness and composition, and exhibits high uniformity and conformal properties.

[0100] S703, thermocouple arms are prepared on the multilayer thermoelectric thin film using an etching process to obtain a multilayer thermocouple pair and a cold load film region.

[0101] In this embodiment, photolithography and dry or wet etching are used to precisely form thermocouple arm patterns on a multilayer structure. One end of each of the multiple thermocouple pairs is concentrated in one region of the thin-film thermoelectric cooler.

[0102] In an optional embodiment, the step of fabricating thermocouple arms on the multilayer thermoelectric thin film using an etching process to obtain a multilayer thermocouple pair includes: coating a photoresist on the multilayer thermoelectric thin film, and forming a pattern on the photoresist with one end of multiple thermocouple pairs concentrated in a region of the thin-film thermoelectric cooler using a photolithography process; and etching multiple thermocouple arms on the multilayer thermoelectric thin film using a photolithography etching process based on the pattern to obtain a multilayer thermocouple pair.

[0103] Specifically, a layer of photoresist is coated onto a multilayer thermoelectric thin film, and a pattern corresponding to the desired thermocouple pair shape is formed on the photoresist using a photolithography process. The selection of photoresist and the conditions of the photolithography process need to be determined based on specific materials and design requirements, and this application embodiment does not impose any limitations on these aspects.

[0104] Then, an etchant (such as a chemical solution in wet etching or a gas plasma in dry etching) is used to etch the multilayer thermoelectric film not protected by photoresist, removing unwanted material. After etching, a photoresist remover is used to completely remove the photoresist from the multilayer thermoelectric film, exposing the final thermocouple pair structure.

[0105] The etching process described above can form multiple thermocouple pairs, and due to the design of the photolithography mask, one end of these thermocouple pairs (usually the cold end) can be concentrated in a specific area of ​​the thin-film thermoelectric cooler. This arrangement helps improve cooling efficiency because the cold end can more effectively remove heat from the cooling area.

[0106] After the thermocouple pair is prepared, the cold load thin film region is prepared by depositing a third insulating layer on the multilayer thermocouple pair; and patterning the third insulating layer using a photolithography etching process to obtain the cold load thin film region.

[0107] See Figure 8 As shown in (e), a 0.5 μm silicon nitride film is deposited as an insulating layer on the patterned thermocouple arm using liquid chemical vapor deposition (LPCVD) to facilitate subsequent etching of the cold load film region and electrode fabrication. After depositing the silicon nitride film as an insulating layer on the thermocouple arm (formed by alternating stacks of P-type and N-type bismuth telluride), the silicon nitride film needs to be patterned using photolithography to determine the actual heat exchange (i.e., the areas generating cold or heat) in the thermoelectric cooling device. This process removes unwanted portions of the silicon nitride film, and the remaining portions cover specific areas of the thermocouple arm; these areas are known as the "cold load film regions."

[0108] The "cold load thin film region" typically refers to the area in a thermoelectric refrigeration device that directly participates in the heat exchange process, meaning it can significantly sense temperature changes (such as cooling or heating). Because silicon nitride film is insulating, it not only protects the thermocouple arm from the external environment but also acts as a thermal insulation layer, allowing heat on the thermocouple arm to be more effectively concentrated or dissipated within a specific area.

[0109] See Figure 8 (f) When patterning silicon nitride thin films, a specific pattern is formed on the silicon nitride thin film using photolithography. Then, etching techniques (such as dry etching or wet etching) are used to remove the silicon nitride portions not protected by photoresist, thereby obtaining the desired "cold load thin film region". The design of this region takes into account the overall structure and performance requirements of the thermoelectric cooling device to ensure that heat can be transferred and exchanged efficiently.

[0110] In an optional embodiment, multiple thermocouple pairs concentrated in one region of the thin-film thermoelectric cooler can be arranged in pairs along the same straight line. Specifically, two thermocouple arms (i.e., at least two thermocouple pairs, each consisting of a P-type thermocouple arm and an N-type thermocouple arm) are arranged along the same straight line, and a predetermined distance is set between them (in order to form a cold load thin-film area).

[0111] Because the thermocouple arms are arranged along the same straight line, forming at least two thermocouple pairs, the cold ends (i.e., the ends that produce the cooling effect) of these thermocouple pairs can be conveniently grouped together. This centralized arrangement helps to utilize the cooling capacity of the cold ends more effectively, since all the cold ends are located in the same area and can work together on the object or space that needs cooling, thereby improving cooling efficiency.

[0112] In this embodiment, the thermocouple arms are arranged along the same straight line and spaced at a predetermined distance, which facilitates thermal management. The hot ends can be designed on both sides of the thermocouple arms, and heat dissipation can be effectively achieved through heat sinks, heat pipes, or other heat dissipation devices.

[0113] S704, using a vacuum coating method, connects one end of a thermocouple pair concentrated in a region of the thin-film thermoelectric cooler through a first electrode to form a cold junction; and connects the other end of the thermocouple pair to a second electrode to form a hot junction.

[0114] In this embodiment, see Figure 8 (g) Depositing 30 nm thick layers of metallic gold using magnetron sputtering. Specifically, a multilayer thermocouple arm is placed in the vacuum chamber of the magnetron sputtering equipment, and the vacuum pump is activated to evacuate the chamber to the required vacuum level, typically a few Pascals or lower, to eliminate interference from gas molecules in the sputtering process. Inside the vacuum chamber, high-energy particles (such as argon ions) bombard the metallic gold target, causing atoms or molecules on the target surface to be sputtered and fly towards the surface of the multilayer thermocouple arm. In magnetron sputtering, a magnetic field is used to control the trajectory of the sputtered particles, making them more concentrated and deposited on specific areas of the thermocouple arm. By adjusting parameters such as sputtering time, power, and the distance between the target and the thermocouple arm, the thickness of the deposited metallic gold layer is precisely controlled to achieve the desired thickness, such as 30 nm.

[0115] See Figure 8 As shown in (h), a layer of photoresist is coated onto the surface of a thermocouple arm on which gold metal has been deposited. The photoresist-coated thermocouple arm is then exposed using a photolithography machine. During exposure, a mask (with patterns of the first electrode, second electrode, and leads printed on it) blocks some of the light, causing the photoresist to react chemically only in the areas where electrodes and leads need to be formed. Then, a developer is used to remove the unexposed or exposed areas (depending on the type of photoresist), leaving a photoresist layer corresponding to the electrode and lead patterns. The unprotected gold layer is then etched away using wet or dry etching techniques. This forms the electrode and lead structures corresponding to the photoresist patterns on the gold layer. Finally, a resist remover is used to remove the remaining photoresist layer, exposing the clear metal electrodes and leads. These electrodes and leads connect the P-type and N-type thermoelectric units, forming a complete thermoelectric cooling device circuit.

[0116] S705 uses an etchant to remove part of the substrate, creating a hollow area on the substrate.

[0117] In this embodiment, see Figure 8(i) As shown, a silicon substrate is etched using 10% tetramethylammonium hydroxide to release the suspended part. In this embodiment, by removing a part of the substrate on the side背离 the thermocouple arm with an etchant, the suspended part is released, reducing the influence of substrate heat transfer.

[0118] In an optional embodiment, the etchant includes any one or more of tetramethylammonium hydroxide, ethylenediamine pyrrolidone, a mixed solution of nitric acid and hydrogen peroxide, a mixed solution of sulfuric acid and hydrogen peroxide, potassium hydroxide, sodium hydroxide, and xenon fluoride.

[0119] In this embodiment, a thermocouple arm beam body with a multi-layer structure is constructed. The body is composed of alternately stacked P-type thermoelectric units and N-type thermoelectric units separated by an insulating layer, forming an efficient thermoelectric conversion unit sequence. At the cold end, the P-type and N-type thermoelectric units are electrically connected through metal electrode buckles, ensuring that charge carriers can migrate smoothly between the interfaces of materials with different energy levels, thereby absorbing heat at the cold end and achieving an efficient refrigeration effect. The refrigeration area is suspended above the substrate, and the dual functions of support and heat transfer are achieved through the layout of multiple thermocouple arms. The hot ends of the thermocouple arms are firmly fixed on the substrate, while the cold ends are suspended and evenly distributed around the refrigeration area. This design not only optimizes the heat conduction path but also enhances the refrigeration efficiency of the refrigeration area. The refrigeration area thin film is directly and closely adhered to the heat source, ensuring that heat can be efficiently transferred from the heat source to the refrigeration area, further improving the performance of the entire refrigeration device.

[0120] Figure 9 Schematic diagrams of the structure of a "hui"-shaped horizontal thin film thermoelectric refrigeration device and its thermocouple arms provided by an embodiment of the present application. Combining Figure 9 As shown, the 1 metal electrode, 2 multi-layer thermocouple arms, 3 cold load thin film area, 4 metal wire, 5 substrate, 6 suspended area, 7 P-type thermoelectric unit, 8 N-type thermoelectric unit, 9 insulating layer.

[0121] In this embodiment, a "hui"-shaped horizontal thin film thermoelectric refrigeration device is constructed. This structure is applicable to most nano-multi-layer thin film thermoelectric devices. Through the surrounding arrangement of multi-layer thermocouple arms formed by stacking P-type thermoelectric units and N-type thermoelectric units, the cold end is concentrated in the cold load area, thereby obtaining an efficient refrigeration power. At the same time, the substrate is hollowed out, and the thermocouple arms can also support the middle refrigeration area as cantilever beams, reducing the influence of substrate heat transfer.

[0122] Figure 10 Schematic diagram of the temperature distribution of a "hui"-shaped horizontal thin film thermoelectric refrigeration device provided by an embodiment of the present application. Combining Figure 10The image shows the temperature distribution along the centerline of a "U"-shaped horizontal thin-film thermoelectric cooler calculated using COMSOL simulation software, with a single thermocouple arm voltage of 0.05V and a central thermal power of 1mW. The lowest temperature is 242.63K, occurring at the end of the thermocouple arm. The temperature rises slightly at the center, reaching 266.23K. The temperature rise is mainly limited by the thermal conductivity of SiNx. These parameters do not represent the theoretical maximum cooling performance; further power increases can be achieved by adjusting the current parameters.

[0123] In this embodiment, simulation software can be used to improve the performance of the fabricated thin-film thermoelectric cooling device.

[0124] In the embodiments of this application, the terms "first" and "second" (if they exist) are used only as name identifiers and do not represent the order of first and second.

[0125] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that all or part of the steps in the methods of the above embodiments can be implemented by means of software plus a general-purpose hardware platform. Based on this understanding, the technical solution of this application can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0126] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the apparatus embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0127] The above description is merely an exemplary implementation of this application and is not intended to limit the scope of protection of this application.

Claims

1. A thin-film thermoelectric cooler, characterized in that, It includes a substrate, a P-type thermoelectric unit, an N-type thermoelectric unit, a first electrode, and a second electrode, wherein the substrate has a hollow area; On one side of the substrate, along a direction perpendicular to the substrate, the P-type thermoelectric unit and the N-type thermoelectric unit are stacked to form a thermocouple pair; the cold end of the thermocouple pair is connected through the first electrode; the hot end of the thermocouple pair is connected to the second electrode. The cold ends of multiple thermocouple pairs are concentrated in one area of ​​the thin-film thermoelectric cooler to form a cold load thin-film area, and the cold ends of multiple thermocouple pairs and the part of the thermocouple arm connected to the cold ends are located in the hollow area of ​​the substrate. The base has a hollow area including an annular hollow section; the annular hollow section has multiple concentric annular slits, multiple radially distributed strip slits, or a combination of multiple concentric annular slits and multiple radially distributed strip slits.

2. The thin-film thermoelectric cooler according to claim 1, characterized in that, The cold load thin film zone is located at the center of the thin film thermoelectric cooler.

3. The thin-film thermoelectric cooler according to claim 2, characterized in that, The cold load film area includes one of the following: rectangular, circular, and complex polygonal shapes.

4. The thin-film thermoelectric cooler according to claim 1, characterized in that, The materials of the P-type thermoelectric unit and the thermoelectric materials of the N-type thermoelectric unit are any one or more of the following: bismuth telluride-based binary or ternary materials, antimony telluride-based binary or ternary materials, lead telluride-based binary or ternary materials, tin selenide-based binary or ternary materials, magnesium-based binary or ternary materials, telluride-based binary or ternary materials, tin-based binary or ternary materials, germanium-silicon alloy materials, semi-Hasler alloys, graphene, squartzite, or filled squartzite materials.

5. A method for preparing a thin-film thermoelectric cooler, characterized in that, The method includes: Provide a base; A multilayer thermoelectric thin film is obtained by sequentially depositing a first insulating layer, a P-type thermoelectric unit layer, a second insulating layer, and an N-type thermoelectric unit layer on one side of the substrate along a direction perpendicular to the substrate. Thermocouple arms are fabricated on the multilayer thermoelectric thin film using an etching process to obtain multilayer thermocouple pairs and a cold load thin film region; one end of each of the multiple thermocouple pairs is concentrated in one region of the thin film thermoelectric cooler. A vacuum coating method is used to connect one end of a thermocouple pair concentrated in a region of the thin-film thermoelectric cooler through a first electrode to form a cold junction; and the other end of the thermocouple pair is connected to a second electrode to form a hot junction. A portion of the substrate is removed using an etchant, creating a hollow area on the substrate. The base has a hollow area including an annular hollow section; the annular hollow section has multiple concentric annular slits, multiple radially distributed strip slits, or a combination of multiple concentric annular slits and multiple radially distributed strip slits.

6. The method for preparing a thin-film thermoelectric cooler according to claim 5, characterized in that, The process of fabricating thermocouple arms on the multilayer thermoelectric thin film using an etching process to obtain a multilayer thermocouple pair includes: Photoresist is coated on the multilayer thermoelectric thin film, and a pattern is formed on the photoresist with one end of multiple thermocouple pairs concentrated in one area of ​​the thin film thermoelectric cooler by photolithography. Based on the pattern, multiple thermocouple arms are etched on the multilayer thermoelectric thin film using photolithography to obtain a multilayer thermocouple pair.

7. The method for preparing a thin-film thermoelectric cooler according to claim 5, characterized in that, The cold load film region is prepared in the following manner: A third insulating layer is deposited on the thermocouple pair of the multilayer structure; The third insulating layer is patterned using a photolithography etching process to obtain a cold-load thin film region.

8. The method for preparing a thin-film thermoelectric cooler according to claim 5, characterized in that, The deposition method is any one or more of chemical vapor deposition, physical vapor deposition, molecular beam epitaxy, sol-gel method, pulsed laser deposition, and atomic layer deposition.

9. The method for preparing a thin-film thermoelectric cooler according to claim 5, characterized in that, The corrosive agent includes any one or more of tetramethylammonium hydroxide, ethylenediaminepyrrolidone, a mixed solution of nitric acid and hydrogen peroxide, a mixed solution of sulfuric acid and hydrogen peroxide, potassium hydroxide, sodium hydroxide, and xenon fluoride.

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