Heat flow sensor utilizing the anomalous Nernst effect and its manufacturing method

Abstract

To provide a heat flow sensor capable of improving sensitivity and a method for manufacturing the same.SOLUTION: A heat flow sensor 10 includes multiple thermoelectric bodies 12 made of a conductive ferromagnetic material having an abnormal Nernst effect, which extend in a first direction, and arranged spaced apart from each other in a second direction different from the first direction, at least some of multiple electrodes 13 extend in the first direction and are arranged on a top of each of multiple thermoelectric bodies, and electrically connecting both ends of the multiple thermoelectric bodies in the first direction to connect the multiple thermoelectric bodies in series, and output can be made from both ends of the multiple thermoelectric bodies connected in series according to a temperature difference between the first main surface below the multiple thermoelectric bodies and the second main surface above the multiple electrodes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat flow measurement technique that utilizes the anomalous Nernst effect. [Background technology]

[0002] The anomalous Nernst effect is a phenomenon in which, when a magnetic material is subjected to a thermal gradient in a magnetic field, a potential difference occurs in a direction perpendicular to both the magnetic field and the thermal gradient. Heat flow sensors that utilize the anomalous Nernst effect can be constructed with a simple structure (see, for example, Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a thermoelectric power generation device in which multiple magnetized thin wires of magnetic material arranged parallel to each other along the surface of a substrate are connected in series with wiring made of a non-magnetic material arranged on the substrate, thereby converting heat flow in a direction perpendicular to the substrate surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-072256 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-103535 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Documents 1 and 2 have a structure in which wiring is arranged between thin wires or single-layer thermoelectric elements on a substrate. Therefore, when the power generation device is miniaturized, it is difficult to ensure the length of the thermoelectric element per installation area, which leads to the problem that sufficient sensitivity to heat flow cannot be obtained.

[0006] An object of the present invention is to provide a heat flow sensor capable of improving sensitivity and a method for manufacturing the same. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a heat flow sensor comprising: a plurality of thermoelectric elements each made of a conductive ferromagnetic material having the anomalous Nernst effect, each extending in a first direction and spaced apart from one another in a second direction different from the first direction; and a plurality of electrodes, at least a portion of each of which extends in the first direction and is arranged above each of the plurality of thermoelectric elements, electrically connected to both ends of the plurality of thermoelectric elements in the first direction to connect the plurality of thermoelectric elements in series; and the plurality of electrodes, at least a portion of each of which extends in the first direction and is arranged above each of the plurality of thermoelectric elements, electrically connected to both ends of the plurality of thermoelectric elements in the first direction to connect the plurality of thermoelectric elements in series; and the heat flow sensor is capable of producing output from both ends of the plurality of thermoelectric elements connected in series in accordance with the temperature difference between a first main surface below the plurality of thermoelectric elements and a second main surface above the plurality of electrodes.

[0008] According to the above aspect, at least a portion of each of the plurality of electrodes electrically connecting the plurality of thermoelectric elements is disposed above the plurality of thermoelectric elements. This eliminates the need for space for electrodes on the layer where the plurality of thermoelectric elements are disposed, allowing the distance between the plurality of thermoelectric elements to be narrowed, allowing the thermoelectric elements to be densely disposed, and the overall length of the thermoelectric elements to be set longer. This improves the sensitivity per area of ​​the region where the thermoelectric elements are disposed, i.e., the region capable of sensing heat flow (also referred to as the "thermosensitive region"), and also enables the heat flow sensor to be miniaturized. Furthermore, because the individual thermoelectric elements and the individual electrodes are disposed along the direction of heat flow from the first principal surface to the second principal surface or from the second principal surface to the first principal surface, the heat flow is collected by the electrodes, and the heat flow conducted through the electrodes is then conducted through the thermoelectric elements, thereby reducing heat flow leakage and enabling efficient detection. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan view of a heat flow sensor according to an embodiment. [Figure 2] 1 is a schematic cross-sectional view of a heat flow sensor according to an embodiment. [Figure 3] FIG. 1 is an explanatory diagram of the anomalous Nernst effect of a thermoelectric material. [Figure 4] 1A to 1C are diagrams illustrating a manufacturing process for a heat flow sensor according to an embodiment. [Figure 5] FIG. 2 is a schematic plan view of a heat flow sensor of Comparative Example 1. [Figure 6] FIG. 10 is an explanatory diagram of a method for measuring the sensitivity of a heat flow sensor. [Figure 7] FIG. 10 is a diagram showing evaluation results of heat flow sensors of an example and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Elements common to multiple drawings will be designated by the same reference numerals, and detailed descriptions of those elements will be omitted.

[0011] Fig. 1 is a schematic plan view of a heat flow sensor according to an embodiment. Fig. 2 is a schematic cross-sectional view of a heat flow sensor according to an embodiment. Fig. 2(a) is a cross-sectional view taken along line AA in Fig. 1. Fig. 2(b) is a cross-sectional view taken along line BB in Fig. 1.

[0012] Referring to Figures 1 and 2, the heat flow sensor 10 has a plurality of thermoelectric elements 12 (shown by solid lines in Figure 1) on a layer (XY plane) on a flat substrate 11, a plurality of electrodes 13 (shown by dashed lines in Figure 2) on a layer above them (Z direction), an insulating layer 14 (or insulating material) covering the plurality of thermoelectric elements 12 and the plurality of electrodes 13 and formed in the gaps between them, and an output terminal 15.

[0013] The thermoelectric elements 12 each extend in the X direction and are spaced apart from one another in the Y direction. The distance L between the opposing side surfaces of adjacent thermoelectric elements 12 is y The narrower the gap, the more densely the thermoelectric elements 12 can be arranged, which is preferable. However, since there is a risk of them coming into contact with each other due to forming errors in the manufacturing process, it is preferable to set the gap to 3 μm to 100 μm.

[0014] Each of the thermoelectric elements 12 is made of an electrically conductive ferromagnetic material having the anomalous Nernst effect. The thermoelectric elements 12 are preferably made of an Fe alloy, such as an FeAl alloy or an FeGa alloy. In the case of an FeAl alloy, the thermoelectric elements 12 have a composition of Fe. 100-x Al xIn the case of an FeGa alloy, the thermoelectric element 12 has a composition of Fe 100-y Ga y In the case of an FeGaB alloy, the thermoelectric element 12 is preferably an FeGaB alloy (Fe 100-y Ga y ) 100-x B x In this case, it is preferable that y is 10 atomic % or more and 32 atomic % or less, and x is 2 atomic % or more and 10 atomic % or less. In the case of an FeGaTa alloy, the thermoelectric element 12 is (Fe 100-y Ga y ) 100-x Ta x In this case, it is preferable that y is 10 atomic % or more and 32 atomic % or less, and x is 1 atomic % or more and 5 atomic % or less.

[0015] The thermoelectric elements 12 are thin films, each having, for example, a thickness of 0.3 μm, a length (in the X direction) of 15 mm, and a width (in the Y direction) of 10 μm. Since a potential difference occurs in the thermoelectric elements 12 depending on their length (in the X direction), the longer they are, the better they are for improving the output voltage, and the narrower the width of the thermoelectric elements 12, the longer the total length of the thermoelectric elements 12 connected in series can be. On the other hand, if the width of the thermoelectric elements 12 is made too narrow, the electrical resistance of the entire thermoelectric element 12 will become excessively large. From these perspectives, the width of the thermoelectric elements 12 is preferably 0.1 μm or more and 100 μm or less, and more preferably 1 μm or more and 10 μm or less.

[0016] The electrode 13 is formed on the layer of the thermoelectric element 12 via an insulating layer 14. The electrode 13 extends in the X direction. As shown in FIG. 2(b), the electrode 13 contacts the end 12a of the thermoelectric element 12 at the end on the left side of the page and is electrically connected to the thermoelectric element 12, and the electrode 13 contacts the end 12b of the thermoelectric element 12 at the end on the right side of the page (not shown) and is electrically connected to the thermoelectric element 12.

[0017] As shown in Fig. 2(a), the electrode 13 is disposed above the thermoelectric element 12, and more specifically, is disposed so as to substantially overlap the thermoelectric element 12 when viewed from above as shown in Fig. 1. However, the bridging portion 13a of the electrode 13 connecting adjacent thermoelectric elements 12 is disposed on the insulating layer 14 between the thermoelectric elements 12. Although the bridging portion 13a is disposed on the right side of the electrode 13 in Fig. 1, it may be disposed in the center or on the left side of the page.

[0018] The electrodes 13 are electrically connected in series so that the potential difference generated across the thermoelectric elements 12 has the same polarity. That is, for all thermoelectric elements 12, the electrodes 13 are formed so as to connect one end 12a of the thermoelectric element 12 to the other end 12b of the adjacent thermoelectric element 12 that is located above the plane of the drawing. Of course, for all thermoelectric elements 12, the electrodes 13 may also be formed so as to connect one end 12a of the thermoelectric element 12 to the other end 12b of the adjacent thermoelectric element 12 that is located below the plane of the drawing.

[0019] The electrodes 13 are made of a non-magnetic conductive material, and may be, but are not limited to, gold (Au), platinum (Pt), aluminum (Al), an aluminum alloy, copper (Cu), or a copper alloy. The electrodes 13 are in the form of thin, thin wires, each having a thickness of 0.4 μm and a width (in the Y direction) of 10 μm, for example.

[0020] The electrodes 13 and thermoelectric element 12 are arranged along the direction of heat flow from the high-temperature body to the low-temperature body. That is, the electrodes 13 and thermoelectric element 12 are arranged upstream and downstream of the heat flow. This allows the heat flow to be introduced to or extracted from the thermoelectric element 12 without escaping, allowing the heat flux to be sensed efficiently and improving sensitivity to the heat flux. Note that although the high-temperature body is arranged on the electrode 13 side and the low-temperature body is arranged on the thermoelectric element 12 side in FIG. 2, the reverse is also possible.

[0021] Figure 3 is an explanatory diagram of the anomalous Nernst effect of a thermoelectric material. Referring to Figure 3 together with Figures 1 and 2, the direction of magnetization M of thermoelectric material 12 is one direction within the plane of thermoelectric material 12 (+Y direction), and the direction of heat flow Q is the thickness direction (-Z direction). An electric field E is generated in the direction perpendicular to these directions (+X direction), resulting in a potential difference between both ends 12a and 12b of thermoelectric material 12 in the X direction. The potential difference is maximum (maximum positive potential difference) when magnetization M of thermoelectric material 12 is oriented in the +Y direction, and is minimum (maximum negative potential difference) when magnetization M is oriented in the -Y direction. The potential difference varies depending on the magnitude and positive / negative sign of the Y-direction component of magnetization M.

[0022] The performance of the anomalous Nernst effect is expressed by the anomalous Nernst coefficient. The direction in which the potential difference occurs is determined by the sign of the anomalous Nernst coefficient. The anomalous Nernst coefficient is expressed by the following formula: E=Sn·ΔT·(L / t) Here, E is the potential difference (X direction) between end 12a and end 12b of thermoelectric body 12, Sn is the anomalous Nernst coefficient of thermoelectric body 12, ΔT is the temperature difference in the thickness direction (Z direction) due to heat flow Q, L is the distance (X direction) between end 12a and end 12b of thermoelectric body 12, i.e., the length of thermoelectric body 12, and t is the thickness of thermoelectric body 12.

[0023] 1, the insulating layer 14 (or insulating material) can be a non-magnetic insulating material, such as a silicon oxide film. The insulating layer 14 is formed between adjacent thermoelectric elements 12 and between adjacent electrodes 13, and covers the thermoelectric elements 12 and electrodes 13. The surface of the heat flow sensor 10 may also be covered with a polyimide film (e.g., Kapton (registered trademark)).

[0024] In the heat flow sensor 10, multiple thermoelectric elements 12 are electrically connected in series by electrodes 13 so that they have the same polarity, and the potential differences generated in the individual thermoelectric elements 12 are added together, outputting the overall output voltage of the thermoelectric elements 12 from between the output terminals 15. In the heat flow sensor 10, multiple thermoelectric elements 12 and multiple electrodes 13 are arranged in different layers along the flow of heat flow. Because there is no need to provide space for electrodes 13 on the layer where multiple thermoelectric elements 12 are arranged, the spacing between the thermoelectric elements 12 can be narrowed, allowing the thermoelectric elements 12 to be arranged more densely. This allows the overall length of the thermoelectric elements 12 connected in series to be increased. Therefore, the heat flow sensor 10 can improve the sensitivity per area of ​​the area where the thermoelectric elements 12 are arranged, i.e., the heat flow sensitive area, and can also be made smaller.

[0025] The heat flow sensor 10 may be provided with a magnetic field application means. A magnet, for example, a permanent magnet (not shown), can be used as the magnetic field application means. The magnetic field application means preferably applies a magnetic field in a direction within the XY plane formed by the X and Y directions, and more preferably applies a magnetic field in a direction perpendicular to the X direction within the XY plane, i.e., the Y direction. The magnets may be disposed on both sides of the heat flow sensor 10 in the Y direction so that a magnetic field is applied along the Y direction. The magnets may be electromagnets. Furthermore, if an external magnetic field is present at the location where the heat flow sensor 10 is installed, the means for generating that external magnetic field may be used as the magnetic field application means.

[0026] [Heat flow sensor manufacturing method] Figure 4 is a manufacturing process diagram of a heat flow sensor according to one embodiment. In the diagram of each process, the left side is a schematic cross-sectional view, and the right side is a schematic plan view. In Figure 4, the left side is a cross-sectional view corresponding to the cross-sectional view taken along line AA in Figure 1, and the right side is a schematic plan view showing a part of the heat flow sensor. The manufacturing method of the heat flow sensor will be described with reference to Figures 4(a) to (d) together with Figures 1 and 2.

[0027] In the step of FIG. 4(a), a thermoelectric film having a thickness of, for example, 0.3 μm is formed on the surface of a substrate 11 such as a silicon substrate (and / or a substrate with a silicon oxide film formed thereon). The method for forming the thermoelectric film is not particularly limited, but may be, for example, a sputtering method or a vacuum deposition method. The thermoelectric film is a conductive ferromagnetic material that exhibits the anomalous Nernst effect of the thermoelectric element 12 described above. Next, the thermoelectric film is shaped by photolithography and dry etching to form the thermoelectric element 12.

[0028] 4(b), a resist film is formed by photolithography to cover both ends 12a, 12b of the thermoelectric element 12 in the X direction, and then an insulating layer, such as a silicon oxide film, having a thickness of, for example, 0.2 μm is formed over the entire surface by CVD, sputtering, or the like. As a result, the thermoelectric element 12 is covered with the insulating layer 14a except for the ends 12a, 12b. The resist film is then removed to expose the ends 12a, 12b of the thermoelectric element 12.

[0029] Next, in the step shown in FIG. 4(c), a resist film with a pattern of electrodes 13 is formed by photolithography. The electrode 13 pattern is formed on top of the thermoelectric elements 12 so as to follow the thermoelectric elements 12. The electrode 13 pattern is set so as to overlap the thermoelectric elements 12 in plan view, and the portion bridging adjacent thermoelectric elements 12 (bridging portion) is disposed on the insulating layer 14a between the thermoelectric elements 12. When the electrode 13 pattern is connected to one side of the thermoelectric element 12, for example, the end 12a on the left side in the figure, it is set so as to connect to the other side of the adjacent thermoelectric element (the upper part of the paper in the figure), that is, the end 12b on the right side in the figure. Next, an electrode film, for example, an Au film, with a thickness of, for example, 0.4 μm is formed on the entire surface by, for example, sputtering or vacuum deposition. It is preferable that the electrode film be thicker than the insulating layer 14 formed in the step shown in FIG. 4(b) in order to prevent disconnection of the electrode film.

[0030] Next, in the step of FIG. 4(d), the resist film is removed, and the electrode film is lifted off except for the electrode 13. As a result, the electrode 13 contacts the thermoelectric element 12 at its ends 12a and 12b, and the remaining portion is formed on the insulating layer 14a. The electrode 13 electrically connects the thermoelectric elements 12 in series so that they have the same polarity. Next, output terminals 15 are formed on both ends of the series circuit formed by the thermoelectric element 12 and the electrode 13. Next, an insulating layer 14b, such as a silicon oxide film, is formed on the entire surface by CVD, sputtering, or the like. The insulating layer 14b is a film for protecting the structure of the heat flow sensor and can be omitted. In this way, the heat flow sensor 10 is formed.

[0031] According to the manufacturing method of this embodiment, the heat flow sensor 10 can be formed by stacking the thermoelectric elements 12 and the electrodes 13, which makes the structure relatively simple and ensures reliable connection between the thermoelectric elements 12 and the electrodes 13. This allows the manufacturing cost of the heat flow sensor 10 to be reduced.

[0032] [Example] The heat flow sensor of the embodiment has a structure similar to that of the heat flow sensor 10 shown in Figures 1 and 2. Referring to Figures 1 and 2, the thermoelectric elements 12 have a width of 10 μm, a length of 12.5 mm, and a thickness of 0.3 μm, and the distance L between adjacent thermoelectric elements 12 in the Y direction is y The distance between the thermoelectric element 12 and the electrode 13 in the Z direction in FIG. 2(a) is 0.2 μm. The ferromagnetic material of the thermoelectric element is Fe3Al. In this example, 800 thermoelectric elements 12 are connected in series via the electrodes 13. The total length of the thermoelectric element 12 in this example is 10 m. The area where the thermoelectric elements 12 are arranged, i.e., the area of ​​the heat-sensing region, is 2.01 × 10 -4 m 2 is.

[0033] [Comparative Example 1] Fig. 5 is a schematic plan view of the heat flow sensor of Comparative Example 1. Referring to Fig. 5, the heat flow sensor 100 of Comparative Example 1 has a plurality of thermoelectric elements 112 on a layer (XY plane) on a flat substrate 101, and a plurality of electrodes 113 each disposed between adjacent thermoelectric elements 112, and the thermoelectric elements 112 and the electrodes 113 are electrically connected in series so that they have the same polarity. Both ends 112a, 112b of the plurality of thermoelectric elements 112 in the X direction are in contact with and electrically connected to the electrodes 113. Output terminals 115 are provided at both ends of the thermoelectric elements 112 and the electrodes connected in series.

[0034] The thermoelectric element 112 of Comparative Example 1 has a width of 10 μm, a length of 5.25 mm, and a thickness of 0.3 μm, and the distance (gap) L between adjacent thermoelectric elements 112 in the Y direction is 1y The distance between the thermoelectric elements 112 and the electrodes 113 in the Y direction is 10 μm. Fe3Al was used as the ferromagnetic material in Comparative Example 1. In Comparative Example 1, 960 thermoelectric elements 112 were connected in series via the electrodes 113. The total length of the thermoelectric elements 112 in Comparative Example 1 was 5.040 m. The area where the thermoelectric elements 112 were arranged, i.e., the area of ​​the heat-sensing region, was 1.50 × 10 -4 m 2 is.

[0035] Comparative Example 2 The heat flow sensor of Comparative Example 2 is a heat flow sensor (Sample 1-1) manufactured by Micromachine Center (MNOIC), a general incorporated foundation, and has the same structure as Comparative Example 1. The thermoelectric element of Comparative Example 2 has a width of 10 μm, a length of 5.25 mm, and a thickness of 0.3 μm, and the distance (gap) between adjacent thermoelectric elements in the Y direction is 30 μm. The distance between the thermoelectric element and the electrode in the Y direction is 10 μm. The ferromagnetic material of Comparative Example 2 is Fe3Al. In Comparative Example 2, 720 thermoelectric elements are connected in series via electrodes. The total length of the thermoelectric element of Comparative Example 2 is 3.780 m. The area where the thermoelectric elements are arranged, i.e., the area of ​​the heat-sensing region, is 1.12 × 10 -4 m 2 is.

[0036] [Measurement method] Fig. 6 is an explanatory diagram of a method for measuring the sensitivity of a heat flow sensor. Referring to Fig. 6, the heat flow sensor of the embodiment is fixed on an aluminum plate with a large enough heat capacity to prevent temperature changes during measurement, and a flat heater is placed above it with an arm, leaving a gap of 0.5 mm. A 1000 W / m 2 A heat flow of 1000 kJ / s was applied to the heat flow sensor. An AC magnetic field (maximum 1850 Oe, period 20 seconds) was applied to the heat flow sensor in the Y direction with respect to a thermoelectric element extending in the X direction. The output voltage of the heat flow sensor was measured using a digital multimeter (Keysight Corporation 34465A) to determine the amplitude of the AC component of the output voltage. Half of this amplitude was defined as the anomalous Nernst voltage. Measurements were also made in Comparative Examples 1 and 2 in the same manner.

[0037] The heat flow of the flat heater was calibrated using a commercially available heat flow sensor manufactured by Denso (Model: Energy Eye, No. D0001). The calibration heat flow sensor was placed at the position shown in Figure 6, and the heat flow measured by the calibration heat flow sensor was 1000 W / m 2 The input voltage and current of the flat heater were set so that

[0038] Fig. 7 shows the evaluation results of the heat flow sensors of the example and the comparative example. Referring to Fig. 7, the anomalous Nernst voltage converted assuming the total length of the thermoelectric element to be 10 m is 2.21 mV for the example, 1.02 mV for comparative example 1, and 1.00 mV for comparative example 2. Therefore, it can be seen that the example is more than twice as large as comparative examples 1 and 2.

[0039] Furthermore, the sensitivity per 10 m of the total length of the thermoelectric body, obtained by dividing the anomalous Nernst voltage converted assuming the total length of the thermoelectric body to be 10 m by the heat flux, was 5.32 × 10 -3 mV / (Wm -2 ) while Comparative Example 1 is 2.36 × 10 -3 mV / (Wm -2 ), and Comparative Example 2 is 2.14 × 10 -3 mV / (Wm -2 ) Therefore, it can be seen that the sensitivity of the example is more than twice as high as that of comparative examples 1 and 2, and the sensitivity per unit length of the thermoelectric material is improved.

[0040] Furthermore, the sensitivity per area of ​​the region where the thermoelectric elements of the heat flow sensor are arranged, i.e., the heat-sensing region, is 26.4 mV / W for the Example, 7.94 mV / W for Comparative Example 1, and 7.22 mV / W for Comparative Example 2. Therefore, it can be seen that the Example is more than three times higher than Comparative Examples 1 and 2. This is because the Example has a configuration in which electrodes are arranged on top of the thermoelectric elements, while Comparative Examples 1 and 2 have a configuration in which electrodes are arranged between the thermoelectric elements and adjacent thermoelectric elements. Therefore, the Example can shorten the distance between the thermoelectric elements compared to Comparative Examples 1 and 2, allowing the thermoelectric elements to be arranged more densely. Furthermore, the Example can form a longer total length of the thermoelectric elements per unit area of ​​the region where the thermoelectric elements are arranged than Comparative Examples 1 and 2. As a result, the Example can improve the sensitivity per area of ​​the heat-sensing region compared to Comparative Examples 1 and 2.

[0041] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the present invention as defined in the claims. [Explanation of symbols]

[0042] 10 Heat flow sensor 11 Circuit Board 12 Thermoelectric body 13 electrodes 14(14a, 14b) Insulating layer 15 Output terminal

Claims

1. a plurality of thermoelectric elements each made of a conductive ferromagnetic material having the anomalous Nernst effect, each extending in a first direction and spaced apart from one another in a second direction different from the first direction; a plurality of electrodes, at least a portion of each of which extends in the first direction and is disposed above each of the plurality of thermoelectric bodies, and which are electrically connected to both ends of the plurality of thermoelectric bodies in the first direction to connect the plurality of thermoelectric bodies in series; outputting from both ends of the plurality of thermoelectric elements connected in series in accordance with a temperature difference between a first main surface below the plurality of thermoelectric elements and a second main surface above the plurality of electrodes; When viewed from the first principal surface or the second principal surface, each of the plurality of electrodes extends in the first direction and is arranged to overlap with each of the plurality of thermoelectric elements, except for a portion of the electrode that is arranged from an upper portion of one of the thermoelectric elements to an upper portion of the other of the adjacent thermoelectric elements. Heat flow sensor.

2. Further comprising an insulating layer between the plurality of thermoelectric elements and the plurality of electrodes, The heat flow sensor according to claim 1 , wherein the plurality of electrodes extend along the first direction via the insulating layer on the plurality of thermoelectric elements.

3. A heat flow sensor as described in claim 1 or 2, further comprising a magnetic field application means for applying a magnetic field to the plurality of thermoelectric elements.

4. A heat flow sensor as described in claim 3, wherein the magnetic field application means applies a magnetic field in a direction within a plane formed by the first direction and the second direction, and perpendicular to the first direction.

5. A step of forming a plurality of thermoelectric elements on a substrate, each of which is made of a conductive ferromagnetic material having the anomalous Nernst effect, wherein each of the plurality of thermoelectric elements extends in a first direction and each of the plurality of thermoelectric elements is arranged spaced apart from each other in a second direction different from the first direction; forming a plurality of electrodes on top of the plurality of thermoelectric elements so that each electrode extends in the first direction along and overlaps each of the plurality of thermoelectric elements, except for a portion that is arranged from the top of one of the thermoelectric elements to the top of the other of adjacent thermoelectric elements, and the plurality of electrodes are electrically connected to both ends of each of the plurality of thermoelectric elements in the first direction to connect the plurality of thermoelectric elements in series.

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