JP2022156629A - Thermoelectric module and method for manufacturing thermoelectric module - Google Patents

Abstract

To provide a thermoelectric module that can suppress the heating temperature of a diffusion treatment.SOLUTION: A thermoelectric module 1 includes a thermoelectric element, an electrode, and a multilayer film having conductivity disposed between the thermoelectric element and the electrode. The multilayer film includes a platinum layer mainly containing platinum, a tin layer mainly containing tin, a nickel layer mainly containing nickel, a palladium layer mainly containing palladium, and a gold layer mainly containing gold. The multilayer film is formed on the surface of the thermoelectric element by sputtering, and the thermoelectric element on which the multilayer film is formed is subjected to a diffusion treatment at a temperature of 150°C or more and 230°C or less.SELECTED DRAWING: Figure 2

Description

The present invention relates to a thermoelectric module and a thermoelectric module manufacturing method.

For example, Patent Document 1 discloses a P-type or N-type thermoelectric element, an electrode joined to the P-type or N-type thermoelectric element, and a thermoelectric element provided between the P-type or N-type thermoelectric element and the electrode. and an intermediate layer formed on the electrode, wherein the intermediate layer is provided between the titanium layer or titanium alloy layer formed on the electrode and the titanium layer or titanium alloy layer and the thermoelectric element. A thermoelectric module is disclosed, characterized in that it comprises an aluminum or aluminum alloy layer coated with a

Further, Patent Document 2 describes a pair of substrates, plate-like electrodes formed on the surfaces of the pair of substrates facing each other, a thermoelectric element joined between the plate-like electrodes, and an external thermoelectric element. an external wiring portion that is a post electrode or a lead wire for electrically connecting to a circuit; a bonding layer that is a sintered body of paste containing metal particles and that bonds the plate-like electrode and the external wiring portion; and a bonding strength improving layer is formed on the interface of the bonding layer to improve the bonding strength with an object to be bonded.

JP-A-2006-49736 JP 2015-18986 A

An object of the present invention is to provide a thermoelectric module capable of suppressing the heating temperature of diffusion treatment.

A thermoelectric module according to the present invention includes a thermoelectric element, an electrode, and a conductive multilayer film disposed between the thermoelectric element and the electrode, wherein the multilayer film is a platinum layer containing platinum as a main component. and a tin layer mainly composed of tin.

Preferably, the multilayer film further comprises a gold layer mainly composed of gold laminated on one or both sides of the tin layer.

Preferably, the thermoelectric element is made of a thermoelectric material containing magnesium,
The tin layer is positioned closer to the electrode than the platinum layer.

Preferably, a palladium layer mainly containing palladium is further provided between the platinum layer and the tin layer and the electrodes, and a nickel layer mainly containing nickel is further provided between the tin layer and the palladium layer. include.

Preferably, the platinum layer is stacked on the thermoelectric element and has a thickness of 50 nm or more and 200 nm or less.

Preferably, the tin layer has a thickness of 10 nm or more and 500 nm or less.

Preferably, the thermoelectric element is made of a porous thermoelectric material, and the nickel layer has a thickness of 200 nm or more and 2000 nm or less.

Preferably, the multilayer film is joined to the electrode via a solder layer, and the multilayer film further includes a gold layer mainly composed of gold between the palladium layer and the solder layer.

Preferably, the multilayer film consists of only the platinum layer, the tin layer, the nickel layer, the palladium layer and the gold layer.

Further, a thermoelectric module manufacturing method according to the present invention includes a multilayer film forming step of forming a multilayer film on a surface of a thermoelectric element by sputtering; a heating step of heating at a temperature, wherein the multilayer film forming step includes forming a platinum layer mainly containing platinum and a tin layer mainly containing tin.

Preferably, the multilayer film forming step further includes a step of forming a palladium layer mainly containing palladium, and further includes a bonding step of soldering the heated multilayer film and the electrode.

According to the present invention, the heating temperature for diffusion treatment can be suppressed.

1 is a cross-sectional view illustrating the configuration of a thermoelectric module 1 according to this embodiment; FIG. 3 is a diagram illustrating in detail the configuration of a multilayer film 20; FIG. 4 is a flow chart illustrating a method (S10) for manufacturing the thermoelectric module 1 in this embodiment. 4 is a diagram illustrating an SEM image of a cross section of the multilayer film 20; FIG. FIG. 4 is a diagram illustrating elemental mapping analysis in a cross section of the multilayer film 20; FIG. 3 is a diagram illustrating the results of a bonding test of thermoelectric modules 1 in Examples 1 and 2; It is a figure which illustrates the modification of the thermoelectric module 1 in this embodiment.

First, the background of the present invention will be described.
A thermoelectric conversion module (hereinafter also referred to as a thermoelectric module) is an assembly in which thermoelectric conversion elements (hereinafter also referred to as thermoelectric elements) are connected in series. When connecting thermoelectric elements in series, the thermoelectric elements and electrodes are often soldered together. When soldering a thermoelectric element and an electrode, it is difficult to directly contact the thermoelectric element with solder. Was.
However, when a magnesium-containing porous thermoelectric material is plated, the thermoelectric material deteriorates, making surface treatment difficult. In addition, as a method other than plating, an aluminum foil, titanium, or titanium-based alloy is sandwiched between the thermoelectric element and the electrode and pressurized and heated to integrate it, or a thermoelectric device in which a diffusion prevention layer is formed by sputtering There is a method in which a paste containing conductive particles including copper balls is sandwiched between the element and the electrode and heated. In any of the above-mentioned methods, in the process of forming the joint structure that joins the thermoelectric element and the electrode, heat of about 300 to 700 ° C is applied to the thermoelectric element, so the material deteriorates, and there is a concern that the function may deteriorate or deteriorate. was there. In addition, even if the thermoelectric element and the electrode are joined by surface treatment, thermoelectric materials (for example, Mg ₂ Ge system, MgSiGe system, Mg ₂ Sn system, MgB ₂ system, Mg ₂ Sb ₃ -based, magnesium-based materials such as MgAgSb-based), there is a concern that the junction resistance will increase.
Therefore, the embodiment of the present invention has been created with the above circumstances as a point of focus. According to the embodiment of the present invention, the heating temperature of the diffusion treatment can be set to a relatively low temperature of 300° C. or less, and the junction resistance can be reduced.

Hereinafter, such embodiments of the present invention will be described with reference to the drawings.
The configuration of a thermoelectric module 1 according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a cross-sectional view illustrating the configuration of a thermoelectric module 1 according to this embodiment.
As illustrated in FIG. 1, the thermoelectric module 1 has a thermoelectric element 10, a multilayer film 20, electrodes 30, a substrate 40, and a solder layer 50. The electrodes 20 and the thermoelectric elements 30 are electrically connected via the multilayer film 40 .

The thermoelectric element 10 is an element made of a material that mutually converts heat and electric energy. The thermoelectric element 10 is composed of a porous thermoelectric material. The thermoelectric material forming the thermoelectric element 10 includes, for example, a silicide-based thermoelectric material. A silicide-based thermoelectric material is specifically a magnesium silicide (Mg ₂ Si)-based thermoelectric material, and more specifically a thermoelectric material mainly composed of an MgSiSn alloy or an Mg ₂ Si alloy (so-called porous magnesium silicide-based thermoelectric material). That is, the thermoelectric element 10 is made of a thermoelectric material containing magnesium. This thermoelectric material includes a matrix composed of Mg ₂ Si and MgO, holes formed in the matrix, and a silicon layer containing silicon as a main component attached to the walls of the holes. The parent phase has two Si-rich phases (referred to as a first Si-rich phase and a second Si-rich phase) having different chemical compositions in the MgSiSn alloy. The first Sn-rich phase has a higher Sn composition ratio than the second Si-rich phase, and the second Si-rich phase has a higher Si composition ratio than the first Sn-rich phase. Also, the thermoelectric material contains 1.0 wt % or more and 20.0 wt % or less of MgO with respect to the weight of the thermoelectric material. Further, the silicon layer constituting the thermoelectric material is composed of amorphous Si, or amorphous Si and microcrystalline Si. Moreover, the porosity of the thermoelectric element 10 is 5% or more and 50% or less. Also, the thermoelectric element 10 may be a magnesium _- based thermoelectric material such as _{Mg2Ge , MgSiGe} , _Mg2Sn , MgB2, _MgIn2O4 , _Mg2Sb3 , and MgAgSb.

The multilayer film 20 is a conductive thin film disposed between the thermoelectric element 10 and the electrode 30 . The multilayer film 20 is joined to the electrode 30 via the solder layer 50 . The multilayer film 20 has a multilayer film 20A and a multilayer film 20B. The multilayer film 20A and the multilayer film 20B have substantially the same configuration, and may be simply referred to as the multilayer film 20 when there is no particular need to distinguish between the multilayer film 20A and the multilayer film 20B. Details of the multilayer film 20 will be described later.

The electrode 30 is a thin plate of conductive metal. The electrodes 30 can be made of materials such as alumite, stainless steel, nickel-iron alloys, copper-nickel alloys, phosphor bronze, copper-iron alloys, copper, platinum, gold, and silver electrodes, for example. In addition, the electrode 30 of this embodiment is a copper thin plate. Electrode 30 is located between substrate 40 and solder layer 50 . The electrodes 30 may be plated for better solderability.

The substrate 40 is a flat plate having an insulating film on one surface. The insulating film provided on one surface of the substrate 40 is a film that electrically disconnects the electrodes 30 and the substrate 40 . The substrate 40 can be manufactured using metal, insulating ceramics, a composite of insulating material such as metal and synthetic resin, or synthetic resin as a base material, and it is preferable to use a material with high thermal conductivity. Specifically, when the substrate 40 is manufactured using a metal base material, it can be manufactured from aluminum, copper, or an alloy containing these. Also, when the substrate 40 is manufactured using an insulating ceramic substrate, it can be manufactured from alumina or aluminum nitride. Further, when the substrate 40 is manufactured using a composite of metal and insulating material such as synthetic resin, it can be manufactured from a base material of copper or aluminum coated with a thin film of insulating resin.
Moreover, when manufacturing the board|substrate 40 using a base material made from a synthetic resin, it can manufacture from glass epoxy resin.

The solder layer 50 is located between the multilayer film 20 and the electrode 30 and is a layer made of a conductive bonding material that bonds the multilayer film 20 and the electrode 30 . That is, the solder layer 50 is a bonding layer made of a bonding material that bonds the multilayer film 20 and the electrode 30 . For the solder used to form the solder layer 50, for example, Pb--Sn-based, Sn--Ag--Cu-based, Sn--Cu-based, Sn--Sb-based, or Sn--Bi-based solder can be used. In this example, Sn--Ag--Cu based lead-free solder (lead-free solder) was used. In addition to solder, for example, a conductive adhesive or brazing material can be used as the bonding material.

FIG. 2 is a diagram illustrating in detail the configuration of the multilayer film 20. As shown in FIG.
As illustrated in FIG. 2, the multilayer film 20 includes a platinum layer 200, a tin layer 201, a nickel layer 202, a palladium layer 204, and a gold layer 206, and in the direction from the thermoelectric element 10 to the substrate 40: A platinum layer 200, a tin layer 201, a nickel layer 202, a palladium layer 204, and a gold layer 206 are laminated in this order. Note that the multilayer film 20 of this example consists of only the platinum layer 200, the tin layer 201, the nickel layer 202, the palladium layer 204, and the gold layer 206,
The platinum layer 200 and the tin layer 201 can be roughly divided into the adhesive layer 22 , and the nickel layer 202 , the palladium layer 204 and the gold layer 206 into the diffusion prevention layer 24 .

The platinum layer 200 is a platinum layer mainly containing platinum. A platinum layer 200 is deposited on the surface of the thermoelectric element 10 to coat the surface of the thermoelectric element 10 and prevent the formation of an oxide layer. The platinum layer 200 has a thickness of 50 nm or more and 200 nm or less, preferably 100 nm or more and 200 nm or less. Note that the platinum layer 200 in this example has a thickness of 100 nm.
The platinum layer 200 is formed using a method such as sputtering, vacuum deposition, ion beam deposition, laser film formation, thermal spraying, plating, or spray coating. Sputtering was used in this example.

The tin layer 201 is a tin layer mainly containing tin. Tin layer 201 is located between platinum layer 200 and nickel layer 202 . The tin layer 201 covers and hardens the surface of the thermoelectric element 10 and acts to reduce oxides on the surface of the material. The tin layer 201 has a thickness of 10 nm or more and 500 nm or less, preferably 300 nm or more and 500 nm or less. Note that the tin layer 201 in this example has a thickness of 400 nm.
In addition, the tin layer 201 is formed using methods such as sputtering, vacuum deposition, ion beam deposition, laser film formation, thermal spraying, plating, and spray coating. Sputtering was used in this example.

The nickel layer 202 is a nickel layer mainly containing nickel. The nickel layer 202 is located between the tin layer 201 and the palladium layer 204 described later. By covering the surface of the thermoelectric element 10 , the nickel layer 202 prevents diffusion of magnesium, which is a constituent element of the thermoelectric element 10 , generated from the thermoelectric element 10 . The nickel layer 202 has a thickness of 200 nm or more and 2000 nm or less, preferably 500 nm or more and 1000 nm or less. Note that the nickel layer 202 has a thickness of 500 nm. Although the diffusion of magnesium can be prevented even when the thickness of the nickel layer 202 is 200 nm or more, the diffusion prevention effect is large when the thickness is about 500 nm. Also, when the thickness of the nickel layer 202 is thicker than 2000 nm, the resistance of the nickel portion increases, and when the thickness is 1000 nm or less, the resistance value can be reduced. Therefore, it is desirable that the thickness of the nickel layer 202 is 500 nm or more and 1000 nm or less.
Also, the nickel layer 202 is formed using a technique such as sputtering, vacuum deposition, ion beam deposition, laser film formation, thermal spraying, plating, or spray coating. Sputtering was used in this example.

The palladium layer 204 is a palladium layer mainly containing palladium. The palladium layer 204 is located between the nickel layer 202 and the gold layer 206 and acts as an anti-repellent for the nickel layer 202 and the solder layer 50 . The palladium layer 204 has a thickness of 50 nm or more and 500 nm or less, preferably 100 nm or more and 200 nm or less. In this example, the thickness is 100 nm. If the thickness of the palladium layer 204 is less than 50 nm, diffusion of the nickel layer 202 cannot be suppressed. Moreover, when the thickness of the palladium layer 204 is thicker than 500 nm, the resistance of the palladium layer 204 increases. Therefore, it is desirable that the thickness of the palladium layer 204 is 50 nm or more and 500 nm or less.
Also, the palladium layer 204 is formed using a technique such as sputtering, vacuum deposition, ion beam deposition, laser film formation, thermal spraying, plating, or spray coating. Sputtering was used in this example.

The gold layer 206 is a gold layer mainly containing gold. Gold layer 206 is located between palladium layer 204 and solder layer 50 . Gold layer 206 acts as an antioxidant for palladium layer 204 . The gold layer 206 has a thickness of 50 nm or more and 500 nm or less, preferably 50 nm or more and 200 nm or less. Note that the gold layer 206 in this example has a thickness of 100 nm. If the thickness of the gold layer 206 is less than 50 nm, the surface of the palladium layer 204 cannot be covered. Further, when the thickness of the gold layer 206 is thicker than 500 nm, the resistance becomes high. Therefore, it is desirable that the thickness of the gold layer 206 is 200 nm or less.
Also, the gold layer 206 is formed using methods such as sputtering, vacuum deposition, ion beam deposition, laser film formation, thermal spraying, plating, and spray coating. Sputtering was used in this example.
Thus, the multilayer film 20 is a thin film including the palladium layer 204 .

Next, a method for manufacturing the thermoelectric module 1 according to this embodiment will be described with reference to FIG.
FIG. 3 is a flow chart illustrating the method (S10) for manufacturing the thermoelectric module 1 according to this embodiment.
As illustrated in FIG. 3, in step 100 (S100), first, the manufacturer removes oxides on the surface of the thermoelectric element 10 by any method such as acid cleaning, reverse sputtering, or polishing. In this example, the oxide is removed by polishing. If there is a thin film of magnesium oxide or the like between the thermoelectric element 10 and the platinum layer 200 to be formed later, the resistance will increase, so it is removed.
Next, the manufacturer forms the multilayer film 20 on the surface of the thermoelectric element 10 using a sputtering phenomenon using a sputtering device. Specifically, the manufacturer forms a thin film of platinum, which is mainly composed of platinum, on the surface of the thermoelectric element 10 so as to have a thickness of 100 nm using a metal mainly composed of platinum (so-called platinum layer 200). formation). Next, after forming the platinum layer 200, the manufacturer forms a thin film of tin, mainly tin, on the platinum layer 200 so as to have a thickness of 400 nm (formation of a so-called tin layer 201). Next, after the formation of the tin layer 201, a nickel thin film mainly composed of nickel is formed over the tin layer 201 so as to have a thickness of 500 nm (formation of a so-called nickel layer 202). Next, after forming the nickel layer 202, the manufacturer forms a thin film of palladium, mainly palladium, on the nickel layer 202 to a thickness of 100 nm (formation of a so-called palladium layer 204). Next, after forming the palladium layer 204, the manufacturer forms a gold thin film, mainly composed of gold, on the palladium layer 204 so as to have a thickness of 100 nm (formation of a so-called gold layer 206). Thus, the manufacturer forms the multilayer film 20 having a five-layer structure on the surface of the thermoelectric element 10 .

In step 101 (S101), the manufacturer forms the multilayer film 20 on the surface of the thermoelectric element 10, and then performs diffusion treatment by heat treatment in an inert atmosphere. The heat treatment temperature is 150° C. or higher and 230° C. or lower, and is 200° C. in this example. If the heat treatment temperature is 150° C. or less, diffusion between metal layers does not occur. Also, if the temperature of the heat treatment is 230° C. or higher, the thermoelectric elements 10 and the electrodes are not joined. Therefore, the heat treatment temperature is preferably 150° C. or higher and 230° C. or lower. By performing heat treatment at a temperature near the melting point of tin, the platinum layer 200 and the tin layer 201 are alloyed with Pt--Sn, and high-purity tin has a reducing effect on oxides on the surface of the thermoelectric element 10 . That is, since no oxide film is formed on the surface of the thermoelectric element 10, the junction resistance can be reduced.
In this example, the case where the diffusion treatment is performed by the heat treatment in an inert atmosphere in S101 is illustrated, but the diffusion treatment may be performed by rapid thermal annealing instead. Moreover, although the case where the heat treatment (S101) is performed after the deposition of the multilayer film 20 (S100) will be described, the heat treatment may be performed simultaneously with the deposition of the multilayer film 20. FIG.

In step 102 (S102), the manufacturer solders the multilayer film 20 formed on the thermoelectric element 10 and the electrode 30 formed in a predetermined size. That is, a solder layer 50 is formed between the multilayer film 20 and the electrode 30 .

In step 104 (S104), the manufacturer bonds the substrate 40 and the electrode 30 with an adhesive so that the thermoelectric element 10 and the electrode 30 with the multilayer film 20 formed thereon are sandwiched between the pair of substrates 40 . Then, the manufacturer seals between the two substrates 40 with a sealing material.
Thus, the manufacturer can manufacture the thermoelectric module 1.

As described above, according to the thermoelectric module 1 of the present embodiment, by forming the multilayer film 20 including the platinum layer 200 and the tin layer 201 on the thermoelectric element 10 made of a magnesium-based porous thermoelectric material, The heat treatment temperature of the diffusion treatment can be performed at a relatively low temperature of 300° C. or lower, and reduction in junction resistance can be realized.
In the above embodiment, the case where the multilayer film 20 including the adhesion layer 22 and the diffusion prevention layer 24 is formed on the thermoelectric element 10 containing an element that is easily diffused has been described. If the thermoelectric element 10 does not contain an element that easily dissolves, the multi-layer film 20 of only the platinum layer 200 and the tin layer 201 (adhesion layer 22) may be formed.

(Verification of Layer Structure of Multilayer Film 20)
FIG. 4 is a diagram illustrating an SEM image of a cross section of the multilayer film 20. As shown in FIG.
FIG. 5 is a diagram illustrating elemental mapping analysis in a cross section of the multilayer film 20. As shown in FIG.
The cross section of the multilayer film 20 in the thermoelectric module 1 of the present embodiment manufactured by the above manufacturing method was photographed with a scanning electron microscope (SEM), and the element distribution was analyzed with an energy dispersive X-ray analyzer (EDX analyzer). .
As a result, as illustrated in FIGS. 4 and 5, the multilayer film 20 has a five-layer structure of a platinum layer 200, a tin layer 201, a nickel layer 202, a palladium layer 204, and a gold layer 206. was able to confirm.

Next, bonding tests of the thermoelectric modules 1 in Examples 1 and 2 were conducted. The details are described below.
FIG. 6 is a diagram illustrating the results of the bonding test of the thermoelectric modules 1 in Examples 1 and 2. FIG. 6A is a diagram illustrating the bonding test result of the thermoelectric module 1 in Example 1, and FIG. 6B is a diagram illustrating the bonding test result of the thermoelectric module 1 in Example 2. FIG.
[Example 1]
(Experiment content)
A Pt/Sn (thickness: 100 nm/400 nm) multilayer film was formed by sputtering on MgSiSn-based and MnSi _γ -based thermoelectric elements (□1.4-2.0×t1.6-5.0). each membrane. Then, heat treatment was performed at 200° C. or 350° C. for 10 minutes in an inert atmosphere.
Specifically, as illustrated in FIG. 6A, in (Test A), a thermoelectric material of n-type MgSiSn, a multilayer film of Pt/Sn, and a heat treatment temperature of 350° C. were performed.
In (Test B), a thermoelectric material of n-type MgSiSn, a multilayer film of Pt/Sn, and a heat treatment temperature of 200°C were performed.
In (Test C), a p-type MgSiSn (1) thermoelectric material, a Pt/Sn multilayer film, and a heat treatment temperature of 200°C were performed.
In (Test D), a p-type MnSi _γ thermoelectric material, a Pt/Sn multilayer film, and a heat treatment temperature of 350° C. were performed.
In (Test E), a p-type MnSi _γ thermoelectric material, a Pt/Sn multilayer film, and a heat treatment temperature of 200° C. were performed.
Then, lead-free solder (Sn--Ag--Cu) is screen-printed to a thickness of 50 μm on the copper electrode joined to the substrate, and the copper electrode screen-printed with lead-free solder and the multilayer film formed on the thermoelectric element. were joined by soldering.

(Experimental result)
As a result, as illustrated in FIG. 6A, it was confirmed that the copper electrodes and the multilayer films formed on the thermoelectric elements were joined by soldering in Tests A to E.

[Example 2]
(Experiment content)
Pt/ _Sn /Ni/Pd/Au (film thickness: 100 nm/400 nm/ 500 nm/100 nm/100 nm) multilayer films are formed. Then, heat treatment was performed at 200° C. or 350° C. for 10 minutes in an inert atmosphere.
Specifically, as exemplified in FIG. 6B, (Test A) is an n-type MgSiSn thermoelectric material, a Pt/Sn/Ni/Pd/Au multilayer film, and a heat treatment temperature of 350°C. rice field.
In (Test B), a thermoelectric material of n-type MgSiSn, a multilayer film of Pt/Sn/Ni/Pd/Au, and a heat treatment temperature of 200°C were performed.
In (Test C), a p-type MgSiSn (1) thermoelectric material, a Pt/Sn multilayer film, and a heat treatment temperature of 200°C were performed.
In (Test D), a thermoelectric material of p-type MgSiSn(2), a multilayer film of Pt/Sn/Ni/Pd/Au, and a heat treatment temperature of 350°C were performed.
In (Test E), a thermoelectric material of p-type MgSiSn (3), a multilayer film of Pt/Sn/Ni/Pd/Au, and a heat treatment temperature of 200°C were performed.
In (Test F), a p-type MnSi _γ thermoelectric material, a Pt/Sn/Ni/Pd/Au multilayer film, and a heat treatment temperature of 350° C. were performed.
In (Test G), a p-type MnSi _γ thermoelectric material, a Pt/Sn/Ni/Pd/Au multilayer film, and a heat treatment temperature of 200° C. were performed.
Then, lead-free solder (Sn--Ag--Cu) is screen-printed to a thickness of 50 μm on the copper electrode joined to the substrate, and the copper electrode screen-printed with lead-free solder and the multilayer film formed on the thermoelectric element. were joined by soldering.

(Experimental result)
As a result, as illustrated in FIG. 6B, it was confirmed that the copper electrodes and the multilayer films formed on the thermoelectric elements were joined by soldering in Tests A to G.
From the above, it is considered that the formation of an oxide film on the surface of the thermoelectric element 10 was suppressed by Pt and Sn, and the bonding was achieved by the diffusion treatment by the inert atmosphere heat treatment.

Next, a modification of the above embodiment will be described. In addition, in the modified example, elements having substantially the same functions and configurations as those of the above-described embodiment are denoted by the same reference numerals, thereby omitting redundant description.
[Modification]
FIG. 7 is a diagram illustrating a modification of the thermoelectric module 1 according to this embodiment. 7A and 7B are diagrams illustrating a thermoelectric module 1 including a multilayer film 20 in which a gold layer 210 is laminated on one side of a tin layer 201, and FIG. 1 is a diagram illustrating a thermoelectric module 1 including a multilayer film 20 in which gold layers 210 are laminated on both surfaces of the thermoelectric module 1. FIG.
As illustrated in FIG. 7 , the multilayer film 20 of this example further has a gold layer 210 in addition to the platinum layer 200 , the tin layer 201 , the nickel layer 202 , the palladium layer 204 and the gold layer 206 .
The gold layer 210 is a gold layer mainly composed of gold laminated on one side or both sides of the tin layer 201 . The gold layer 210 illustrated in FIG. 7A is positioned between the tin layer 201 and the nickel layer 202, and the gold layer 210 illustrated in FIG. 7B is positioned between the platinum layer 200 and the tin layer 201. is doing. That is, the gold layer 210 is laminated on one side of the tin layer 201 . Further, the gold layer 210 illustrated in FIG. 7C includes a gold layer 210A and a gold layer 210B, the gold layer 210A is located between the tin layer 201 and the nickel layer 202, and the gold layer 210B and the tin layer 201 . That is, the gold layer 210 is laminated on both sides of the tin layer 201 . The gold layer 210 coats the surface of the tin layer 201 by alloying it with gold and tin, and improves the resistance to heat treatment so that the tin layer 201 is not perforated during heat treatment.
Thus, according to the thermoelectric module 1 of this example, by laminating the gold layer 210 on one side or both sides of the tin layer 201, it is possible to perform the heat treatment temperature of the diffusion treatment at a relatively low temperature of 300° C. or less. becomes.

DESCRIPTION OF SYMBOLS 1... Thermoelectric module 10... Thermoelectric element 20... Multilayer film 22... Adhesive layer 200... Platinum layer 201... Tin layer 24... Diffusion prevention layer 202... Nickel layer 204... Palladium layer 206... Gold layer 30... Electrode 40... Substrate 50... Solder Layer 210... gold layer

Claims (11)

a thermoelectric element;
an electrode;
a conductive multilayer film disposed between the thermoelectric element and the electrode,
The thermoelectric module, wherein the multilayer film includes a platinum layer mainly containing platinum and a tin layer mainly containing tin. 2. The thermoelectric module according to claim 1, wherein the multilayer film further includes a gold layer mainly composed of gold laminated on one side or both sides of the tin layer. The thermoelectric element is made of a thermoelectric material containing magnesium,
The thermoelectric module according to claim 2, wherein the tin layer is positioned closer to the electrode than the platinum layer. a palladium layer mainly composed of palladium between the platinum layer and the tin layer and the electrode;
The thermoelectric module according to claim 3, further comprising a nickel layer mainly containing nickel between the tin layer and the palladium layer. The thermoelectric module according to claim 4, wherein the platinum layer is stacked on the thermoelectric element and has a thickness of 50 nm or more and 200 nm or less. The thermoelectric module according to claim 5, wherein the tin layer has a thickness of 10 nm or more and 500 nm or less. The thermoelectric element is made of a porous thermoelectric material,
The thermoelectric module according to claim 6, wherein the nickel layer has a thickness of 200 nm or more and 2000 nm or less. The multilayer film is joined to the electrode via a solder layer,
8. The thermoelectric module according to claim 7, wherein the multilayer film further includes a gold layer mainly containing gold between the palladium layer and the solder layer. 9. The thermoelectric module according to claim 8, wherein the multilayer film is composed only of the platinum layer, the tin layer, the nickel layer, the palladium layer, and the gold layer. a multilayer film forming step of forming a multilayer film on the surface of the thermoelectric element by sputtering;
a heating step of heating the thermoelectric element on which the multilayer film is formed at a temperature of 150° C. or more and 230° C. or less;
The thermoelectric module manufacturing method, wherein the multilayer film forming step includes forming a platinum layer mainly containing platinum and a tin layer mainly containing tin. The multilayer film forming step further includes forming a palladium layer mainly composed of palladium,
11. The method of manufacturing a thermoelectric module according to claim 10, further comprising a joining step of joining the heated multilayer film and the electrodes with solder.

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