A deep waterproof thermoelectric cooler and its preparation method

Abstract

This invention belongs to the technical field of semiconductor packaging, specifically relating to a deep waterproof thermoelectric cooler and its preparation method. It includes an upper ceramic substrate, a lower ceramic substrate, a semiconductor cooling column located between them, and metal electrode layers disposed at both ends of the cooling column. The circumferential gap of the semiconductor cooling column is filled with a closed-cell elastic sealing medium and foamed to form a continuous sealing layer. The edges of the upper and lower ceramic substrates are processed with trapezoidal extrusion arms, peripheral extrusion arms, and peripheral sealing steps. After assembly, a multi-layer waterproof pressing structure is formed at the edges. An external pressure-adaptive covering shell formed by a mold is applied. This significantly improves waterproof performance while ensuring thermoelectric cooling efficiency, enabling stable operation in extreme environments such as deep water, high humidity, and strong condensation. It is suitable for outdoor cooling, temperature control of diving equipment, and thermal management of special electronic devices.

Description

Technical Field

[0001] This invention belongs to the technical field of semiconductor packaging, specifically relating to a deep waterproof thermoelectric cooler and its preparation method. Background Technology

[0002] Thermoelectric coolers, as solid-state refrigeration components, are widely used in electronic equipment heat dissipation, precision instrument temperature control, and portable cooling devices due to their compact structure, lack of moving mechanical parts, and bidirectional cooling capability. They achieve temperature difference transfer between hot and cold ends through the Seebeck effect. However, in practical applications, thermoelectric coolers often need to operate in harsh environments such as high humidity, rain, or even liquid immersion, and their waterproof sealing performance directly affects the lifespan and stability of the device.

[0003] Existing technologies mostly use epoxy resin, silicone rubber, or hot melt adhesive as encapsulation and sealing materials, achieving waterproofing through edge coating or filling. However, such single-layer sealing structures are prone to interface peeling, microcracks, or hardening failure of the sealing layer under long-term thermal cycling and moisture action. This allows moisture to seep into the semiconductor component along the gap between the ceramic substrate and the encapsulating adhesive, corroding the solder layer and reducing thermoelectric performance. The outer protective structure is usually made of rigid plastic or a single layer of elastic material, lacking the ability to automatically adjust to changes in external pressure, which easily leads to stress concentration in local areas, further weakening the sealing effect.

[0004] Therefore, existing thermoelectric coolers still have significant shortcomings in structural design, selection of waterproof media materials, and sealing methods. There is an urgent need for a comprehensive protection solution that can achieve compression sealing and combine an outer pressure adaptive coating structure to improve the long-term waterproof capability and overall reliability of thermoelectric coolers in high humidity and underwater environments. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a deep waterproof thermoelectric cooler, comprising an upper ceramic substrate, a lower ceramic substrate, multiple pairs of P-type and N-type semiconductor pillars located between the upper and lower ceramic substrates, metal electrode welding layers disposed at the upper and lower ends of the semiconductor pillars, and an encapsulation and sealing structure.

[0006] The upper ceramic substrate and the lower ceramic substrate have trapezoidal extrusion arms, outer peripheral extrusion arms, and outer peripheral sealing steps;

[0007] The encapsulation and sealing structure includes: a closed-cell elastic sealing medium and an outer pressure-adaptive encapsulation shell;

[0008] The closed-cell elastic sealing medium is disposed between the trapezoidal extrusion arm, the P-type semiconductor pillar and the N-type semiconductor pillar, and between the outer peripheral extrusion arm and the outer pressure adaptive coating shell;

[0009] When the upper ceramic substrate and the lower ceramic substrate are subjected to relative longitudinal pressure, the following occurs:

[0010] T1: The trapezoidal extrusion arm applies oblique extrusion to the closed-cell elastic sealing medium, causing it to undergo elastic deformation with increased pressure between the P-type semiconductor pillar and the N-type semiconductor pillar;

[0011] T2: The peripheral extrusion arm applies longitudinal extrusion to the closed-cell elastic sealing medium, causing it to undergo elastic deformation with increased pressure between the upper ceramic substrate, the lower ceramic substrate and the outer pressure adaptive covering shell.

[0012] As a preferred technical solution, the outer pressure adaptive covering shell has an outer peripheral shell and a locking arm; the locking arm cooperates with the outer peripheral sealing step; and a closed-cell elastic sealing medium is provided between the outer peripheral shell and the outer peripheral squeezing arm.

[0013] As a preferred technical solution, a closed-cell elastic sealing medium is provided between the engaging arm and the outer peripheral sealing step.

[0014] As a preferred technical solution, the outer pressure adaptive coating shell is formed by laminating an inner fluororubber layer and an outer polyether block amide layer. The inner fluororubber layer has a Shore A hardness of 50-60, and the outer polyether block amide layer has a Shore A hardness of 90-100.

[0015] As a preferred technical solution, the closed-cell elastic sealing medium is a fluorinated elastomer foam sealing material with a closed-cell rate of 95% to 98%; the fluorinated elastomer foam sealing material is a composite of fluorinated liquid silicone rubber and hollow glass microspheres, the glass microspheres having a particle size of 5 to 20 μm and a volume fraction of 20% to 35%.

[0016] As a preferred technical solution, the exposed surfaces of the upper ceramic substrate 1, the lower ceramic substrate 2, the P-type semiconductor pillar, the N-type semiconductor pillar, and the metal electrode welding layer are covered with an oxide-fluoride composite hydrophobic barrier layer containing rare earth fluoride crystal phases, and the surface water contact angle is 160°±5°.

[0017] As a preferred technical solution, the oxide-fluoride composite hydrophobic barrier layer is an alumina matrix with a thickness of 200-500 nm, and the rare earth fluoride crystal phase is lanthanum fluoride or cerium fluoride.

[0018] As a preferred technical solution, the total thickness of the outer pressure adaptive coating shell is 0.6 to 1.2 mm.

[0019] As a preferred technical solution, the upper ceramic substrate and the lower ceramic substrate are aluminum nitride ceramics with a thickness of 0.3 to 0.6 mm and a thermal conductivity of 150 to 180 W / (m·K).

[0020] This invention provides a method for preparing a deeply waterproof thermoelectric cooler, comprising the following steps:

[0021] S1. Multiple pairs of P-type semiconductor pillars and N-type semiconductor pillars are respectively welded to the upper and lower ends of the metal electrode welding layer to form a semiconductor component.

[0022] S2. Fix the semiconductor component in the molding mold, and inject closed-cell elastic sealing medium material into the space between the corresponding P-type semiconductor pillar, N-type semiconductor pillar and metal electrode welding layer and the outer peripheral sealing space. The material is formed by mixing fluorinated liquid silicone rubber and hollow glass microspheres at a mass ratio of 100:(20-35). The hollow glass microspheres have a particle size of 5-20 μm and a volume fraction of 20%-35%, and 0.5%-1.5% peroxide curing agent by mass is added.

[0023] S3. The closed-cell elastic sealing medium material is heated, foamed, and cured for 2-5 hours at 80-120 ℃ and 0.05-0.1 MPa to achieve a closed-cell rate of 95%-98% and a Shore A hardness of 70-80.

[0024] S4. The edges of the upper ceramic substrate and the lower ceramic substrate are machined to form a trapezoidal extrusion arm, an outer peripheral extrusion arm and an outer peripheral sealing step.

[0025] S5. Assemble the processed upper ceramic substrate and lower ceramic substrate to both sides of the semiconductor component, so that the trapezoidal extrusion arm and the outer peripheral extrusion arm cooperate with the closed-cell elastic sealing medium, and the outer peripheral sealing step corresponds to the locking arm.

[0026] S6. Form an outer pressure adaptive coating shell in a mold. The coating shell includes an inner fluororubber layer and an outer polyether block amide layer. The Shore A hardness of the inner fluororubber layer is 50-60, the Shore A hardness of the outer polyether block amide layer is 90-100, and the total thickness is 0.6-1.2 mm.

[0027] As a preferred technical solution, the closed-cell elastic sealing medium raw material in step S2 is stirred at low speed for 8 to 12 minutes at 25 to 35 ℃ before injection to uniformly disperse the hollow glass microspheres, and after adding the curing agent, it is stirred for another 5 to 8 minutes to form a uniform reaction material.

[0028] As a preferred technical solution, the machining in step S4 is performed using CNC precision cutting, and the inclination angle of the trapezoidal extrusion arm 6 is 10° to 15°.

[0029] As a preferred technical solution, step S6 includes the following sub-steps:

[0030] S61. Material preparation: Select fluororubber raw materials to prepare fluororubber mixtures, add 0.5% to 1.5% by mass of peroxide vulcanizing agent to the mixtures, and stir for 5 to 10 minutes at 25 to 35 ℃; Select polyether block amide raw materials to prepare polyether block amide mixtures.

[0031] S62. Surface treatment: Plasma treatment or sandblasting treatment is performed on the outer surface of the upper ceramic substrate 1 and the lower ceramic substrate 2 and the outer peripheral sealing step 8 area, and a titanium transition layer with a thickness of 50-150 nm is deposited on the treated surface.

[0032] S63, Inner Fluororubber Layer Molding: The treated component is loaded into the first mold cavity, fluororubber mixture is injected into the cavity and filled under pressure until it fits against the outer surface of the outer extrusion arm, and the inner fluororubber layer is obtained by heating and vulcanizing at 150-170 ℃ for 8-12 min.

[0033] S64. Molding of outer polyether block amide layer: The component with inner fluororubber layer is inserted into the second mold cavity, and polyether block amide mixture is injected into the cavity and melted and bonded to the outer surface of inner fluororubber layer. The mixture is kept at 180-200 ℃ for 5-8 min.

[0034] S65. Curing and Cooling: Maintain a pressure of 0.05-0.1 MPa in the mold for secondary vulcanization of the double-layer coating structure for 1-2 hours, and then cool at room temperature for 15-25 minutes.

[0035] S66. Demolding and Inspection: Demold and remove the molded outer pressure adaptive shell assembly, and check its total thickness to be 0.6 to 1.2 mm. The thickness ratio of the inner fluororubber layer to the outer polyether block amide layer is 1:1 to 1:1.5.

[0036] As a preferred technical solution, the fluororubber raw material mentioned in step S61 is a ternary copolymer fluororubber with a fluorine content of 65% to 70%, which is made by copolymerization of hexafluoropropylene, tetrafluoroethylene and perfluoroalkyl vinyl ether, and has a Mooney viscosity of 60 to 80 mL (1+10) @ 100 °C.

[0037] As a preferred technical solution, the polyether block amide raw material in step S61 is a thermoplastic elastomer formed by alternating copolymerization of polyamide hard segments and polyether soft segments. The relative viscosity of the polyamide hard segments is 1.6–1.9, the number-average molecular weight of the polyether soft segments is 600–2000, and the total density is 1.01–1.03 g / cm³. 3 .

[0038] Beneficial effects:

[0039] This invention achieves high-density filling of the sealing medium under bidirectional pressure in both longitudinal and oblique directions by in-situ injection and foaming of a closed-cell elastic sealing medium between P-type semiconductor pillars, N-type semiconductor pillars and metal electrode welding layers, combined with trapezoidal extrusion arms and peripheral extrusion arms formed by processing the edges of the upper and lower ceramic substrates, which significantly improves sealing stability and anti-seepage performance.

[0040] The outer pressure-adaptive encapsulation shell is constructed by laminating an inner fluororubber layer and an outer polyether block amide layer. The difference in material hardness causes synergistic compression under external pressure, further enhancing the sealing effect. The oxide-fluoride composite hydrophobic barrier layer covering the upper and lower ceramic substrates and the exposed surfaces of the semiconductor components forms a nanoscale hydrophobic interface, effectively preventing moisture penetration. This multi-layered sealing design combined with in-situ molding technology enables the device to maintain long-term stable operation in complex humid and hot environments, while also ensuring structural strength and thermal conductivity, making it suitable for thermoelectric and refrigeration applications under long-term high humidity or liquid immersion conditions. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the thermoelectric cooler of the present invention;

[0042] Figure 2 This is a schematic diagram of the structure of the upper ceramic substrate of the thermoelectric cooler of the present invention;

[0043] Figure 3 This is a schematic diagram of the structure of the lower ceramic substrate of the thermoelectric cooler of the present invention;

[0044] Figure 4 This is a schematic diagram of the outer pressure adaptive covering shell of the thermoelectric cooler of the present invention. Detailed Implementation

[0045] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0046] Example 1

[0047] This embodiment provides a deeply waterproof thermoelectric cooler. Its overall structure and sealing protection design are designed to maintain long-term stable thermoelectric cooling performance under high humidity and high water pressure environments, and significantly extend the service life of the device.

[0048] like Figure 1As shown, the cooler includes an upper ceramic substrate 1, a lower ceramic substrate 2, multiple pairs of P-type semiconductor pillars 3 and N-type semiconductor pillars 4 located between the upper and lower ceramic substrates, metal electrode welding layers 5 disposed at the upper and lower ends of the semiconductor pillars, and a packaging and sealing structure.

[0049] In this embodiment, both the upper ceramic substrate 1 and the lower ceramic substrate 2 are made of aluminum nitride ceramic with a thickness of 0.3 to 0.6 mm and a thermal conductivity of 150 to 180 W / (m·K) to ensure excellent thermal conductivity during the temperature difference transfer process on both sides of the cooler, while maintaining sufficient mechanical strength to withstand external pressure impact.

[0050] Between two ceramic substrates, multiple pairs of P-type semiconductor pillars 3 and N-type semiconductor pillars 4 are evenly spaced, and they are arranged alternately to form a Seebeck circuit. The height, cross-sectional shape, and distribution density of the P-type and N-type semiconductor pillars are optimized according to the actual cooling power requirements. In this embodiment, a design with a height of 1.0 to 1.5 mm and a square cross-sectional side length of 0.8 to 1.0 mm is adopted, and a rectangular array structure is used in the arrangement direction to reduce thermal resistance and resistance unevenness.

[0051] Each semiconductor pillar is connected to the conductive circuit of the ceramic substrate through a metal electrode welding layer 5 at both the top and bottom. The welding layer material is nickel-plated copper foil with tin-lead alloy solder on the surface. The thickness of the welding layer is controlled at 30-50 μm to reduce contact resistance and enhance mechanical bonding.

[0052] like Figure 2 , Figure 3 As shown, the outer edge structure of the upper ceramic substrate 1 and the lower ceramic substrate 2 is processed into three parts: a trapezoidal extrusion arm 6, an outer peripheral extrusion arm 7, and an outer peripheral sealing step 8. The inclination angle of the trapezoidal extrusion arm 6 is 10° to 15°, and the resulting inclined compression surface can close inward when longitudinal force is applied, enhancing the extrusion force on the internal sealing medium; the width of the outer peripheral extrusion arm 7 is 0.8 to 1.2 mm, which is used to provide axial compression space in the direction of the outer sealing ring; the height of the outer peripheral sealing step 8 is 0.5 to 0.8 mm, which can achieve a stable fit with the locking arm of the outer covering shell to form a secondary waterproof barrier.

[0053] The sealing structure includes a closed-cell elastic sealing medium 9 and an outer pressure-adaptive covering shell 10, wherein the closed-cell elastic sealing medium 9 is distributed in two locations:

[0054] (1) A sealing gap is filled between the trapezoidal extrusion arm 6 and the semiconductor pillar to prevent longitudinal water seepage;

[0055] (2) Between the outer peripheral extrusion arm 7 and the outer pressure adaptive covering shell 10, the penetration of peripheral moisture and liquid water is blocked.

[0056] When longitudinal pressure is applied externally, the sealing action consists of two parts:

[0057] T1 section: The trapezoidal extrusion arm 6 compresses the internal closed-cell elastic sealing medium 9 with oblique force, causing it to undergo elastic deformation between the semiconductor pillars, increasing the local pressure and effectively filling the tiny gaps;

[0058] T2 section: The outer peripheral extrusion arm 7 applies longitudinal extrusion to the outer sealing medium, forcing it to generate a high-pressure sealing ring between the ceramic substrate and the outer covering shell, forming a second waterproof barrier.

[0059] like Figure 4 As shown, the outer pressure adaptive covering shell 10 is composed of an outer peripheral shell 11 and a locking arm 12. The locking arm 12 and the outer peripheral sealing step 8 engage with each other to form a stable mechanical connection. A second layer of closed-cell elastic sealing medium 9 is arranged at the locking part to form a sealing area with local stress concentration.

[0060] The outer shell is made of a double-layer composite material: the inner layer is fluororubber (Shore A hardness 50-60), which has excellent oil resistance, acid and alkali resistance, and high and low temperature resistance; the outer layer is polyether block amide (Shore A hardness 90-100), which combines high strength and impact resistance. The total thickness is controlled between 0.6 and 1.2 mm to ensure sufficient protective strength and a certain degree of flexibility.

[0061] The closed-cell elastic sealing medium 9 has a closed-cell rate controlled at 95%–98%. Its material is a composite of fluorinated liquid silicone rubber and hollow glass microspheres, wherein the glass microspheres have a particle size of 5–20 μm and a volume fraction of 20%–35%. The closed-cell structure can deform uniformly and rebound rapidly under pressure, and the hollow glass microspheres endow it with excellent dimensional stability and water permeability resistance.

[0062] To further prevent moisture from entering the semiconductor contact surface, the exposed surfaces of the upper ceramic substrate 1, lower ceramic substrate 2, P-type semiconductor pillar 3, N-type semiconductor pillar 4, and metal electrode welding layer 5 are all covered with an oxide-fluoride composite hydrophobic barrier layer. This coating uses alumina as the matrix (thickness 200–500 nm) and disperses rare earth fluoride crystal phases (lanthanum fluoride or cerium fluoride) inside. The surface water contact angle reaches 160°±5°, exhibiting superhydrophobic properties and effectively blocking the adhesion of liquid water.

[0063] Example 2

[0064] This embodiment provides a semiconductor power device packaging assembly with a closed-cell elastic sealing structure and an outer pressure adaptive encapsulation shell, the preparation method of which is as follows:

[0065] S1. Preparation and connection of semiconductor pillars and metal electrode bonding layers:

[0066] P-type and N-type semiconductor pillars with a diameter of 2.5 mm and a length of 10 mm were selected. The materials were boron-doped silicon single crystal and phosphorus-doped silicon single crystal, respectively, with resistivity controlled between 0.01 and 0.05 Ω·cm to ensure low on-resistance characteristics of the power device under operating current. Nickel-plated copper-based pads were used for the metal electrode bonding layer, with a thickness controlled at 0.2 mm to improve bonding strength and current carrying capacity.

[0067] First, the end face of the semiconductor pillar is plasma cleaned to remove surface oxides and organic residues. Then, Sn-3.0Ag-0.5Cu (SAC305) lead-free solder is used to firmly weld the end face of the semiconductor pillar to the metal electrode solder layer through a vacuum reflow soldering process. The peak value of the soldering temperature profile is set at 245 ℃, and the holding time is controlled at 60 s to ensure that the solder is fully wetted and forms a dense intermetallic compound layer.

[0068] S2. Injection and foaming molding of closed-cell elastic sealing media:

[0069] The gap between the weld layer and the adjacent semiconductor pillar is filled with a fluororubber-based closed-cell elastic sealing medium. The fluororubber raw material is selected from fluorinated ethylene-propylene copolymer (FEPM), with a Mooney viscosity controlled at 60~80 ML (1+10)@100 ℃. 2 phr of organic peroxide crosslinking agent, 10 phr of microspherical foaming agent, and an appropriate amount of carbon black reinforcing filler are added, and the mixture is uniformly mixed using a planetary mixer.

[0070] The infusion method is quantitative injection. After uniformly injecting the adhesive into the gap between the metal electrode layer and the semiconductor pillar, it is preheated at 120 °C for 5 min to activate the foaming agent, and then kept at 180 °C for 15 min to allow the material to fully cross-link and complete the shaping of the closed-cell structure. The compression set of this closed-cell sealing medium is controlled within 25% to ensure that the device can maintain its sealing performance under long-term pressure.

[0071] S3, Ceramic substrate edge structure processing:

[0072] Both the upper and lower ceramic substrates are made of high-purity aluminum nitride ceramic. Trapezoidal extrusion arms, outer peripheral extrusion arms, and outer peripheral sealing steps are formed at their mating edges through CNC grinding. The thickness of the main planar area is 1 mm. The trapezoidal extrusion arms have a base width of 1.5 mm, a top width of 0.8 mm, and a height of 0.6 mm; the outer peripheral extrusion arms have a thickness of 0.5 mm and a height of 0.8 mm; and the outer peripheral sealing step has a width of 1.2 mm and a height of 0.4 mm. This structure can generate multi-directional compression for the closed-cell elastic sealing medium during subsequent component assembly, enhancing sealing reliability and dispersing external mechanical impacts.

[0073] S4. Assembly of upper and lower ceramic substrates with semiconductor welding components:

[0074] The upper and lower ceramic substrates are placed on either side of the semiconductor pillar and aligned using a precision positioning fixture to ensure that the vertical center deviation between the P-type and N-type semiconductor pillars does not exceed 0.05 mm. Then, moderate mechanical pressure is applied to pre-compress the closed-cell elastic sealing medium using the trapezoidal extrusion arm and the outer peripheral extrusion arm. Simultaneously, the outer peripheral sealing step contacts the sealing medium to form an outer ring seal, thereby improving overall airtightness and the uniformity of medium filling.

[0075] S5. Mold forming of the outer pressure adaptive covering shell:

[0076] Polyether block amide (PEBA) was used as the coating shell material, with a Shore hardness of 72D selected to balance elastic recovery and impact resistance. After vacuum drying, the PEBA material was used for secondary coating molding using a temperature-controlled injection mold. A 1.5 mm coating layer thickness was pre-reserved within the mold cavity according to the component's shape, and an arc-shaped transition section was formed around the perimeter to prevent stress concentration. During the coating molding process, the mold temperature was controlled at 70 ℃, the injection temperature at 200 ℃, the injection pressure at 60 MPa, the holding time at 30 s, and the cooling time at 90 s. After removal, visual and dimensional inspections were performed to ensure a tight fit between the coating shell and the ceramic substrate and sealing medium, forming a unified outer protective structure.

[0077] Through the above steps, this embodiment not only achieves a firm connection between the semiconductor pillar and the metal electrode, but also provides a long-term stable sealing effect through the closed-cell elastic sealing medium and the multi-layer mechanical compression structure. At the same time, the outer pressure adaptive encapsulation shell further enhances the device's impact resistance and environmental adaptability.

[0078] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A deep waterproof thermoelectric cooler, comprising an upper ceramic substrate (1), a lower ceramic substrate (2), multiple pairs of P-type semiconductor pillars (3) and N-type semiconductor pillars (4) located between the upper and lower ceramic substrates, metal electrode bonding layers (5) disposed at the upper and lower ends of the semiconductor pillars, and an encapsulation and sealing structure, characterized in that: The upper ceramic substrate and the lower ceramic substrate have trapezoidal extrusion arms (6), outer peripheral extrusion arms (7), and outer peripheral sealing steps (8). The encapsulation and sealing structure includes: a closed-cell elastic sealing medium (9) and an outer pressure adaptive covering shell (10). The closed-cell elastic sealing medium is disposed between the trapezoidal extrusion arm (6), the P-type semiconductor pillar (3) and the N-type semiconductor pillar (4), and between the outer peripheral extrusion arm (7) and the outer pressure adaptive covering shell (10); When the upper ceramic substrate (1) and the lower ceramic substrate (2) are subjected to relative longitudinal pressure, the following occurs: T1: The trapezoidal extrusion arm (6) applies oblique extrusion to the closed-cell elastic sealing medium (9), causing it to undergo elastic deformation with increased pressure between the P-type semiconductor pillar (3) and the N-type semiconductor pillar (4); T2: The peripheral extrusion arm (7) applies longitudinal extrusion to the closed-cell elastic sealing medium (9), causing it to undergo elastic deformation with increased pressure between the upper ceramic substrate (1), the lower ceramic substrate (2) and the outer pressure adaptive covering shell (10).

2. The deep waterproof thermoelectric cooler according to claim 1, characterized in that: The outer pressure adaptive covering shell (10) has an outer peripheral shell (11) and a locking arm (12); the locking arm (12) cooperates with the outer peripheral sealing step (8); a closed-cell elastic sealing medium (9) is provided between the outer peripheral shell (11) and the outer peripheral extrusion arm (7).

3. The deep waterproof thermoelectric cooler according to claim 2, characterized in that: A closed-cell elastic sealing medium (9) is provided between the locking arm (12) and the outer peripheral sealing step (8).

4. The deep waterproof thermoelectric cooler according to claim 1, characterized in that: The outer pressure adaptive coating shell (10) is formed by stacking an inner fluororubber layer and an outer polyether block amide layer. The inner fluororubber layer has a Shore A hardness of 50 to 60, and the outer polyether block amide layer has a Shore A hardness of 90 to 100.

5. The deep waterproof thermoelectric cooler according to claim 1, characterized in that: The closed-cell elastic sealing medium (9) is a fluorinated elastomer foam sealing material with a closed-cell rate of 95% to 98%; the fluorinated elastomer foam sealing material is a composite of fluorinated liquid silicone rubber and hollow glass microspheres, with a particle size of 5 to 20 μm and a volume fraction of 20% to 35%.

6. The deep waterproof thermoelectric cooler according to claim 1, characterized in that: The exposed surfaces of the upper ceramic substrate (1), lower ceramic substrate (2), P-type semiconductor pillar (3), N-type semiconductor pillar (4) and metal electrode welding layer (5) are covered with an oxide-fluoride composite hydrophobic barrier layer containing rare earth fluoride crystal phases, and the surface water contact angle is 160°±5°.

7. The deep waterproof thermoelectric cooler according to claim 6, characterized in that: The oxide-fluoride composite hydrophobic barrier layer is an alumina matrix with a thickness of 200–500 nm, and the rare earth fluoride crystal phase is lanthanum fluoride or cerium fluoride.

8. The deep waterproof thermoelectric cooler according to claim 1, characterized in that: The upper ceramic substrate (1) and the lower ceramic substrate (2) are aluminum nitride ceramics with a thermal conductivity of 150-180 W / (m·K).

9. A method for preparing a deep waterproof thermoelectric cooler, characterized in that, Includes the following steps: S1. Multiple pairs of P-type semiconductor pillars (3) and N-type semiconductor pillars (4) are respectively welded to the upper and lower ends of the metal electrode welding layer (5) to form a semiconductor assembly; S2. Fix the semiconductor component in the molding mold, and inject closed-cell elastic sealing medium material into the space between the corresponding P-type semiconductor pillar (3), N-type semiconductor pillar (4) and metal electrode welding layer (5) and the outer peripheral sealing space. The material is formed by mixing fluorinated liquid silicone rubber and hollow glass microspheres at a mass ratio of 100: (20~35). The hollow glass microspheres have a particle size of 5~20 μm and a volume fraction of 20%~35%, and 0.5%~1.5% peroxide curing agent is added by mass. S3. The closed-cell elastic sealing medium material is heated, foamed, and cured for 2-5 hours at 80-120 ℃ and 0.05-0.1 MPa to achieve a closed-cell rate of 95%-98% and a Shore A hardness of 70-80. S4. The edges of the upper ceramic substrate (1) and the lower ceramic substrate (2) are machined to form a trapezoidal extrusion arm (6), an outer peripheral extrusion arm (7) and an outer peripheral sealing step (8). S5. The processed upper ceramic substrate (1) and lower ceramic substrate (2) are assembled to both sides of the semiconductor component, so that the trapezoidal extrusion arm (6) and the outer peripheral extrusion arm (7) cooperate with the closed-cell elastic sealing medium (9), and the outer peripheral sealing step (8) corresponds to the locking arm (12). S6. Form an outer pressure adaptive coating shell (10) in a mold. The coating shell includes an inner fluororubber layer and an outer polyether block amide layer. The Shore A hardness of the inner fluororubber layer is 50-60, the Shore A hardness of the outer polyether block amide layer is 90-100, and the total thickness is 0.6-1.2 mm.

10. The preparation method according to claim 9, characterized in that: Before injection, the closed-cell elastic sealing medium raw material is stirred at low speed for 8-12 minutes at 25-35 ℃ to uniformly disperse the hollow glass microspheres. After adding the curing agent, stirring is continued for 5-8 minutes to form a uniform reaction material.

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