JP2012004333A - Thermoelement and method of manufacturing thermoelement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric element capable of efficiently generating a temperature difference in a thermoelectric pattern.
A first through hole is formed in an insulating first substrate. The first heat transfer medium is disposed in a part of the first through hole. The first end face of the first heat transfer medium facing the same direction as the first face is located at a position lower than the first face of the first substrate. A thermoelectric pattern made of a thermoelectric material that is thermally coupled to the first end surface of the first heat transfer medium is disposed on the first surface. The second heat transfer medium is thermally coupled to the thermoelectric pattern at a different location than the first heat transfer medium. The first heat transfer medium and the second heat transfer medium protrude in opposite directions with respect to the thermoelectric pattern.
[Selection] Figure 1

Description

  The present invention relates to a thermoelectric element and a manufacturing method thereof.

  A flexible thermoelectric element has been proposed for mounting on a heating element having a curved surface. A pattern made of a thermoelectric conversion material is sandwiched between two flexible sheets. In plan view, a heat transfer member having a high thermal conductivity is provided on one outer surface of the sheet so as to overlap a part of the thermoelectric pattern. A heat transfer member is also provided on the opposite outer surface so as to overlap with other portions of the thermoelectric pattern.

  When a temperature difference in the thickness direction occurs in the sheet, one heat transfer member becomes high temperature and the other heat transfer member becomes low temperature. Due to the temperature difference between the heat transfer members, a temperature difference in the in-plane direction occurs in the substrate. This temperature difference causes a temperature difference in the in-plane direction in the thermoelectric pattern.

JP 2006-186255 A

  Heat is transferred from the heat transfer member provided on the high temperature outer surface to the thermoelectric pattern via the high temperature side sheet. Thereby, a part of thermoelectric pattern becomes high temperature. However, the heat of this part is cooled via the low temperature side sheet. For this reason, the temperature rise at the high temperature end of the thermoelectric pattern is suppressed. Further, heat is transmitted to the portion where the thermoelectric pattern is to be cooled via the high temperature side sheet. For this reason, the cooling efficiency of the low temperature end of the thermoelectric pattern is lowered.

  A thermoelectric element capable of efficiently generating a temperature difference in a thermoelectric pattern is desired.

According to one aspect of the invention,
An insulating first substrate;
A first through hole formed in the first substrate;
A first end face disposed in a part of the first through hole and having a first end face facing the same direction as the first face at a position lower than the first face of the first substrate; A heat transfer medium;
A thermoelectric pattern comprising a thermoelectric material disposed on the first surface and thermally coupled to the first end surface of the first heat transfer medium;
A second heat transfer medium thermally coupled to the thermoelectric pattern at a position different from that of the first heat transfer medium and projecting in the opposite direction to the first heat transfer medium with respect to the thermoelectric pattern; A thermoelectric element is provided.

According to another aspect of the invention,
Forming a plurality of first through holes in an insulating first substrate;
A part of the inside of each of the first through holes is filled with a first heat transfer medium, and the first heat transfer medium is disposed at a position lower than one first surface of the first substrate. Arranging the end face of
Forming a thermoelectric pattern thermally coupled to the first heat transfer medium on the first surface;
There is provided a method of manufacturing a thermoelectric element, comprising: a step of thermally coupling a second heat transfer medium to the thermoelectric pattern at a position different from the first heat transfer medium.

  By making the first end face lower than the first face, the temperature of the portion of the thermoelectric pattern that is thermally coupled to the first heat transfer medium and the temperature of the first heat transfer medium are brought close to each other. Can do. Thereby, a big temperature difference can be produced in a thermoelectric pattern.

(1A) is a plan view of one substrate of the thermoelectric element according to Example 1, and (1B) is a cross-sectional view of the thermoelectric element. FIG. 2 is a cross-sectional view of a cavity of a thermoelectric element according to Example 1 and its surroundings. 1 is a cross-sectional view in the middle of manufacturing a thermoelectric element according to Example 1. FIG. 1 is a cross-sectional view in the middle of manufacturing a thermoelectric element according to Example 1. FIG. (4A) and (4B) are isotherm diagrams showing simulation results of temperature distribution in the thermoelectric elements of Example 1 and Comparative Example, respectively. It is a graph which shows the simulation result of the temperature distribution of the in-plane direction of the thermoelectric pattern of the thermoelectric element of Example 1 and a comparative example. (6A) and (6B) are cross-sectional views in the course of manufacturing a thermoelectric element according to Example 2. 6C is a cross-sectional view of the thermoelectric element according to Example 2. FIG. (7A) and (7B) are cross-sectional views of the thermoelectric element according to Example 3 in the course of manufacturing, and (7C) is a cross-sectional view of the thermoelectric element according to Example 3. (8A) and (8B) are cross-sectional views in the middle of manufacturing the thermoelectric element according to Example 4. (9A) and (9B) are cross-sectional views in the course of manufacturing a thermoelectric element according to Example 5, and (9C) are cross-sectional views of the thermoelectric element according to Example 5. FIG. 10 is a cross-sectional view of the thermoelectric element according to Example 5 when operating.

[Example 1]
FIG. 1A shows a plan view of one substrate (first substrate) of the thermoelectric element according to the first embodiment. A thermoelectric pattern 21 is formed on the insulating first substrate 20. The thermoelectric pattern 21 has a planar shape bent in a crank shape, and includes a plurality of P-type thermoelectric patterns 21P and N-type thermoelectric patterns 21N alternately connected in series. The P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N are electrically connected to each other by the conductive film 22.

  In FIG. 1A, two P-type thermoelectric patterns 21P and two N-type thermoelectric patterns 21N are alternately arranged in a portion extending in the horizontal direction (row direction) of the crank-shaped thermoelectric pattern 21. In a portion extending in the vertical direction (column direction), a conductive film 22 that connects ends of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N in adjacent rows is disposed.

  Positions corresponding to every other conductive film 22 selected from the plurality of conductive films 22 arranged along the path of the thermoelectric pattern 21 (for example, the odd-numbered conductive films 22 when serial numbers are assigned in order from 1). In addition, a through hole 25 penetrating the first substrate 20 is formed. For the conductive film 22 that connects the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N in the column direction, the connection portion between the P-type thermoelectric pattern 21P and the conductive film 22, and the N-type thermoelectric pattern and the conductive film. A first through hole 25 is formed in each of the connecting portions to the 22. The first heat transfer medium 30 is embedded in a part of the through hole 25.

  Electrode films 24 acting as electrodes of thermoelectric elements are formed at both ends of the path of the thermoelectric pattern 21. One electrode film 24 is connected to the end of the P-type thermoelectric pattern 21P, and the other electrode film 24 is connected to the end of the N-type thermoelectric pattern 21N.

  FIG. 1B is a cross-sectional view taken along one-dot chain line 1B-1B in FIG. 1A. A plurality of through holes 25 are formed in the first substrate 20. Each side surface of the through-hole 25 has a tapered shape that spreads outward in the vicinity of the opening at both ends. The first heat transfer medium 30 is embedded in a part of the through hole 25. A flexible insulating sheet is used for the first substrate 20. As an example, polyimide, kapton, polycarbonate, polyethylene, polyethylene terephthalate (PET), polysulfone (PSF), polyethersulfone (PES), polyetherethylketone (PEEK), polyphenylenesulfite (PPS), or the like can be used. . An appropriate material may be selected from these materials depending on the operating temperature, operating environment, etc. of the thermoelectric element.

  For the first heat transfer medium 30, a material having a higher thermal conductivity than the first substrate 20, for example, a metal such as solder is used.

  The end surface (first end surface) 30A of the first heat transfer medium 30 facing the same direction as one surface (first surface) 20A of the first substrate 20 is disposed at a position lower than the first surface 20A. Is done. As an example, the position of the first end face 30 </ b> A in the depth direction substantially coincides with the deepest position of the tapered side surface of the first through hole 25. The other end surface (second end surface) 30B of the first heat transfer medium 30 is disposed at substantially the same height as the other surface (second surface) 20B of the first substrate 20.

  An insulating film 31 is formed on the first surface 20 </ b> A of the first substrate 20 and the first end surface 30 </ b> A of the first heat transfer medium 30. For the insulating film 31, for example, silicon oxide, silicon nitride or the like is used. A P-type thermoelectric pattern 21P and an N-type thermoelectric pattern 21N are formed on the first substrate 20 with an insulating film 31 interposed therebetween.

  The P-type thermoelectric pattern 21P passes from the region on the first end surface 30A toward the adjacent first heat transfer medium 30 via the tapered side surface of the first through-hole 25, and passes through the first surface 20A. Extends to the upper area. The N-type thermoelectric pattern 21N passes from the region on the first end face 30A through the tapered side surface of the first through hole 25 in the opposite direction to the P-type thermoelectric pattern 21P, and then on the first face 20A. Extends to the area.

  The ends of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N on the first end face 30A are thermally coupled to the first heat transfer medium 30 via the insulating film 31. A P-type thermoelectric material such as chromel is used for the P-type thermoelectric pattern 21P. An N-type thermoelectric material such as constantan is used for the N-type thermoelectric pattern 21N.

Other materials may be used as the thermoelectric material. For example, BiTe materials, PbTe materials, Si-Ge materials, silicide materials, skutterudite materials, transition metal oxide materials, zinc antimony materials, boron compounds, cluster solids, zinc oxide materials, carbon Nanotubes or the like can be used. Examples of BiTe-based materials include BiTe, SbTe, BiSe, and these compounds. Examples of PbTe-based materials include PbTe, SnTe, AgSbTe, GeTe, and compounds thereof. Examples of the Si—Ge material include Si, Ge, and SiGe. Examples of the silicide material include FeSi, MnSi, CrSi and the like. Examples of the skutterudite-based material include compounds represented by MX ₃ and RM ₄ X ₁₂ . Here, M is Co, Rh, or Ir, X is As, P, or Sb, and R represents La, Yb, or Ce. Examples of transition metal oxide materials include NaCoO, CaCoO, ZnInO, SrTiO, BiSrCoO, PbSrCoO, CaBiCoO, BaBiCoO, and the like. An example of the zinc antimony material is AnSb. Examples of the boron compound include CeB, BaB, SrB, CaB, MgB, VB, NiB, CuB, and LiB. Examples of cluster solids include B clusters, Si clusters, C clusters, AlRe, AlReSi, and the like. An example of the zinc oxide-based material is ZnO.

  An end portion of the P-type thermoelectric pattern 21P and an end portion of the N-type thermoelectric pattern 21N are disposed on each of the first end faces 30A. A conductive film 22 electrically connects the two ends. A conductive film 22 connecting the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N respectively extending from the first heat transfer medium 30 on both sides is provided approximately in the middle of the first heat transfer media 30 adjacent in the row direction. Is formed. For the conductive film 22, for example, copper (Cu), silver (Ag), aluminum (Al), gold (Au), platinum (Pt), or the like is used.

  A plurality of second through holes 41 are formed in the second substrate 40. Similar to the first through hole 25, the vicinity of the opening on the side surface of the second through hole 41 has a tapered structure. A second heat transfer medium 42 is embedded in the second through hole 41. The end surfaces on both sides of the second heat transfer medium 42 are disposed at substantially the same height as the surface of the second substrate 40, respectively. The same material as that of the first substrate 20 and the first heat transfer medium 42 is used for the second substrate 40 and the second heat transfer medium 42, respectively.

  The first surface 40 </ b> A of the second substrate 40 and the first surface 20 </ b> A of the first substrate 20 face each other, and both are bonded via an adhesive layer 50. The second heat transfer medium 42 is disposed at a position overlapping the conductive film 22 on the first substrate 20 in plan view. The second heat transfer medium 42 is thermally coupled to the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N via the adhesive layer 50. A cavity 45 is formed between the first heat transfer medium 30 and the second substrate 40.

  As described above, the first heat transfer medium 30 and the second heat transfer medium 42 are thermally coupled to the thermoelectric pattern 21 at different positions. Further, the first heat transfer medium 30 and the second heat transfer medium 42 protrude in opposite directions with respect to the thermoelectric pattern 21. Focusing on each of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N, the first heat transfer medium 30 is thermally coupled to one end portion of one pattern, and the second heat transfer is connected to the other end portion. Medium 42 is thermally coupled.

  FIG. 2 shows a cross-sectional view of the cavity 45 and its surroundings. An insulating film 31 is disposed between the P-type thermoelectric pattern 21P and the first heat transfer medium 30, and between the N-type thermoelectric pattern 21N and the first heat transfer medium 30. The insulating film 31 electrically insulates the first heat transfer medium 30 from the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N. The insulating film 31 does not hinder heat transfer between the P-type thermoelectric pattern 21P and the first heat transfer medium 30 and between the N-type thermoelectric pattern 21N and the first heat transfer medium 30. It is preferable to make it as thin as possible. Conversely, it is preferable to secure a sufficient thickness to prevent a short circuit between the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N and the first heat transfer medium 30. For example, the thickness of the insulating film 31 is preferably in the range of 0.01 μm to 1 μm.

  With reference to FIG. 3A-FIG. 3G, the manufacturing method of the thermoelectric element by Example 1 is demonstrated.

  As shown in FIG. 3A, a plurality of first through holes 25 are formed in the first substrate 20. The thickness of the first substrate 20 is, for example, 125 μm. Laser processing or mechanical drilling can be applied to the formation of the first through hole 25. By adjusting the laser processing conditions and the machine drilling conditions, it is possible to form a through hole having a tapered vicinity in the vicinity of the opening. The planar shape of the first through hole 25 is, for example, a circle. In addition to a circle, it may be a quadrilateral or other polygons.

  In general, the processing conditions are optimized so that a straight through-hole that does not have a large diameter is formed in the vicinity of the opening. In the first embodiment, the through hole 25 having a tapered opening can be formed by shifting the processing condition from the optimum condition for forming a straight through hole.

  As shown in FIG. 3B, the first heat transfer medium 30 is embedded in a part of the first through hole 25. Hereinafter, a method of embedding the first heat transfer medium 30 will be described. The solder paste is embedded in the first through-hole 25 from the second surface 20 </ b> B using a mask having an opening that matches the position of the first through-hole 25. The amount of the solder paste is adjusted so that the embedded solder paste does not reach the first surface 20A.

  After embedding the solder paste, a heat treatment is performed to volatilize the resin in the solder paste. The heat treatment temperature is set to 200 ° C., for example. Since the solder paste does not reach the first surface 20A, the position of the first end surface 30A of the first heat transfer medium 30 is lower than that of the first surface 20A, and the recess 20C is formed. The second end surface 30B of the first heat transfer medium 30 has substantially the same height as the second surface 20B.

  As shown in FIG. 3C, an insulating film 31 is formed on the first surface 20A and the first end surface 30A. For the insulating film 31, for example, an insulator such as silicon oxide or silicon nitride is used. For example, sputtering is applied to the formation of the insulating film 31.

  As shown in FIG. 3D, a P-type thermoelectric pattern 21P made of, for example, chromel is formed on the insulating film 31. For the formation of the P-type thermoelectric pattern 21P, sputtering using a metal mask having an opening that matches the planar shape is applied. The thickness of the P-type thermoelectric pattern 21P is, for example, 1 μm. Since the vicinity of the opening of the first through-hole 25 is tapered, the P-type thermoelectric element does not cause disconnection from the end on the first end face 30A to the end on the first face 20A. A pattern 21P can be formed.

  As shown in FIG. 3E, an N-type thermoelectric pattern 21N made of, for example, constantan is formed on the insulating film 31. For the formation of the N-type thermoelectric pattern 21N, sputtering using a metal mask having an opening that matches the planar shape is applied. The thickness of the N-type thermoelectric pattern 21N is, for example, 1 μm. Similarly to the P-type thermoelectric pattern 21P, the N-type thermoelectric pattern 21N can be formed from the end portion on the first end face 30A to the end portion on the first face 20A without causing disconnection.

  As shown in FIG. 3F, a conductive film 22 made of, for example, copper (Cu) is formed. The conductive film 22 is formed by sputtering using a metal mask having an opening that matches the planar shape. The thickness of the conductive film 22 is, for example, 0.3 μm.

  As shown to FIG. 3G, the 2nd through-hole 41 is formed in the 2nd board | substrate 40, and the 2nd heat-transfer medium 42 is embedded in it. The thickness of the second substrate 40 is, for example, 75 μm. The method for forming the second through hole 41 and the second heat transfer medium 42 is the same as the method for forming the first through hole 25 and the first heat transfer medium 30 shown in FIGS. 3A and 3B. However, since the second substrate 40 is thinner than the first substrate 20, the second heat transfer medium 42 fills the second through hole 41 almost completely. As a result, the end surfaces on both sides of the second heat transfer medium 42 are substantially the same height as the surface of the second substrate 40.

  The adhesive layer 50 is formed by applying an adhesive to one surface of the second substrate 40. The surface on which the adhesive layer 50 is formed is opposed to the first surface 20 </ b> A of the first substrate 20. The first substrate 20 and the second substrate 40 are aligned so that the second heat transfer medium 42 overlaps the conductive film 22 substantially in the middle of the adjacent first heat transfer medium 30. By curing the adhesive layer 50, the thermoelectric element shown in FIG. 1B is obtained.

  Next, the operation of the thermoelectric element according to Example 1 will be described. A temperature difference is generated between the outer surface of the first substrate 20 shown in FIG. 1B and the outer surface of the second substrate 40. For example, the outer surface of the first substrate 20 is coupled to a first heat source, and the outer surface of the second substrate 40 is coupled to a second heat source. One of the first heat source and the second heat source is a high temperature side heat source, and the other is a low temperature side heat source. As an example, a first heat source in contact with the outer surface of the first substrate 20 is a low-temperature side heat source, and a second heat source in contact with the outer surface of the second substrate 40 is a high-temperature side heat source.

  The thermal conductivity of the first heat transfer medium 30 and the second heat transfer medium 42 is higher than that of the first substrate 20 and the second substrate 40. For this reason, a heat flow path is formed from the high-temperature second heat source to the low-temperature first heat source via the second heat transfer medium 42, the P-type thermoelectric pattern 21P, and the first heat transfer medium 30. The Furthermore, a heat flow path is formed from the second heat source to the first heat source via the second heat transfer medium 42, the N-type thermoelectric pattern 21N, and the first heat transfer medium 30. Thereby, a temperature difference in the in-plane direction is generated in the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N. Due to this temperature difference, a thermoelectromotive force is generated.

  A thin adhesive layer 50 is only inserted between the second heat transfer medium 42 and the P-type thermoelectric pattern 21P and between the second heat transfer medium 42 and the N-type thermoelectric pattern 21N. . Further, only a thin insulating film 31 is inserted between the first heat transfer medium 30 and the P-type thermoelectric pattern 21P and between the first heat transfer medium 30 and the N-type thermoelectric pattern 21N. is there. For this reason, the high temperature end of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N can be efficiently heated. Further, the low temperature ends of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N can be efficiently cooled.

  The thermal conductivity of the second substrate 40 is lower than the thermal conductivity of the second heat transfer medium 42, but part of the heat is conducted in the thickness direction from the outer surface of the second substrate 40, The first surface 40 is reached. In the first embodiment, a cavity 45 is formed between the first heat transfer medium 30 and the second substrate 40. The cavity 45 acts as a heat insulating material. For this reason, inflow of heat from the high temperature part to the low temperature ends of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N can be suppressed. Since the opening part of the 1st through-hole 25 is made into the taper shape, the heat insulation effect can be heightened more compared with the case of a straight shape.

  Further, the height of the first heat transfer medium 30 is lower than the thickness of the first substrate 20. For this reason, the heat flow path between the low temperature ends of the P-type thermoelectric pattern 21 </ b> P and the N-type thermoelectric pattern 21 </ b> N and the first heat source becomes shorter than the thickness of the first substrate 20. As a result, the low temperature end can be efficiently cooled.

  A simulation result of the temperature distribution will be described with reference to FIGS. 4A and 4B. FIG. 4A shows a simulation result of the structure corresponding to Example 1 in which the cavity 45 is formed, and FIG. 4B shows a simulation result of the structure of the comparative example in which the cavity is not formed. The outer surface of the first substrate 20 was 0 ° C., and the outer surface of the second substrate 40 was 100 ° C. In FIG. 4A and FIG. 4B, the isotherm is shown by a curve.

  When the cavity 45 is provided, an isothermal line of 10 ° C. intersects the thermoelectric pattern 21 as shown in FIG. 4A. This means that the temperature at the low temperature end of the thermoelectric pattern 21 is 10 ° C. or less. On the other hand, when the cavity is not formed, the isotherm of 10 ° C. to 40 ° C. does not intersect the thermoelectric pattern 21 as shown in FIG. 4B. This means that the temperature at the low temperature end of the thermoelectric pattern 21 is 40 ° C. or higher.

  FIG. 5 shows the temperature distribution obtained from the simulation results. The horizontal axis represents the distance from the high temperature end of the thermoelectric pattern in units of μm, and the vertical axis represents the temperature in units of “° C.”. A solid line a and a broken line b indicate the temperature distributions of the structures of FIGS. 4A and 4B, respectively.

  In the structure of FIG. 4A corresponding to Example 1, the temperature difference between the high temperature end and the low temperature end is 36.1 ° C., whereas in the structure of the comparative example, the temperature difference is 13.6 ° C. Thus, by adopting the structure of Example 1, a larger temperature difference can be generated in the thermoelectric pattern 21. As the temperature difference increases, the output power of thermoelectric power generation also increases.

  The substrate bonding step shown in FIG. 3G is performed in the atmosphere, for example, but may be performed in a vacuum. When performed in a vacuum, the inside of the cavity 45 can be evacuated. By using an adhesive having a performance capable of maintaining a vacuum for a long period of time as the adhesive layer 50, the cavity 45 can be kept in a vacuum for a long period of time. When the cavity 45 is evacuated, the heat insulation effect by the cavity 45 can be enhanced.

  In Example 1, the insulating film 31 for insulating the thermoelectric pattern 21 and the first heat transfer medium 30 was formed. It is necessary to insulate both the plurality of first heat transfer media 30 from each other when the outer surface of the first substrate 20 is brought into contact with the conductive first heat source. It is because it ends. When the first heat source is not conductive, it is not necessary to insulate the thermoelectric pattern 21 from the first heat transfer medium 30. In this case, the insulating film 31 may be omitted and the thermoelectric pattern 21 may be in direct contact with the first heat transfer medium 30.

  Further, when the first heat source is conductive, an insulating film may be formed on the outer surface of the first substrate 20 and the outer end surface of the first heat transfer medium 30. In this case, since the plurality of first heat transfer media 30 are not short-circuited with each other, the insulating film 31 can be omitted.

[Example 2]
A thermoelectric element according to Example 2 will be described with reference to FIGS. 6A to 6C. In the following description, paying attention to differences from the first embodiment, the description of the same configuration as the first embodiment is omitted.

  As shown in FIG. 6A, the first through hole 25, the first heat transfer medium 30, the insulating film 31, the P-type thermoelectric pattern 21P, the N-type thermoelectric pattern 21N, and the conductive film 22 are formed on the first substrate 20. Form. In Example 1, the P-type thermoelectric pattern 21 </ b> P and the N-type thermoelectric pattern 21 </ b> N extending in a direction approaching each other from the adjacent first heat transfer medium 30 were connected by the conductive film 22. In Example 2, both are not connected, and the space | interval of the front-end | tip is wider than the space | interval of the structure of Example 1. FIG.

  An adhesive layer 51 is formed on the insulating film 31 so as not to overlap the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N.

  In Example 1, the end surfaces on both sides of the second heat transfer medium 42 formed on the second substrate 40 were almost the same height as the surface of the second substrate 40. In the second embodiment, one end surface (first end surface) 42 </ b> A of the second heat transfer medium 42 is similar to the first heat transfer medium 30 in the surface (first surface) 40 </ b> A of the second substrate 40. Is lower than. For this reason, a recess 40 </ b> C is formed in the opening of the second through hole 41.

  An insulating film 32 is formed on the first surface 40 </ b> A of the second substrate 40. For the insulating film 32, for example, the same insulating material as that of the insulating film 31 is used. On the insulating film 32, a P-type thermoelectric pattern 21P, an N-type thermoelectric pattern 21N, and a conductive film 22 are formed. These structures are the same as those of the P-type thermoelectric pattern 21P, the N-type thermoelectric pattern 21N, and the conductive film 22 formed on the first surface 20A of the first substrate 20.

  An adhesive layer 51 is formed on the insulating film 32 so as not to overlap the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N.

  As shown in FIG. 6B, the first surface 20A of the first substrate 20 and the first surface 40A of the second substrate 40 are opposed to each other. In plan view, the first substrate 20 and the second substrate 40 are aligned so that the second heat transfer medium 42 is positioned between the first heat transfer media 30 adjacent to each other. At this time, the P-type thermoelectric pattern 21P formed on the first substrate 20 and the P-type thermoelectric pattern 21P formed on the second substrate 40 partially overlap. Similarly, the N-type thermoelectric pattern 21N formed on the first substrate 20 and the N-type thermoelectric pattern 21N formed on the second substrate 40 partially overlap.

  As shown in FIG. 6C, the P-type thermoelectric patterns 21P are brought into contact with each other, and the N-type thermoelectric patterns 21N are brought into contact with each other. The first substrate 20 and the second substrate 40 are bonded together by curing the adhesive layer 51. The electrical connection between the P-type thermoelectric patterns 21P and the N-type thermoelectric patterns 21N is ensured by ultrasonic bonding or thermocompression bonding.

  In the second embodiment, the cavity 46 is also formed between the second heat transfer medium 42 and the first substrate 20. For this reason, the heat flow between the outer surface of the first substrate 20 and the second heat transfer medium 42 can be suppressed. Thereby, compared with Example 1, a temperature difference can be produced more efficiently at both ends of each of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N.

[Example 3]
A thermoelectric element according to Example 3 will be described with reference to FIGS. 7A to 7C. In the following description, paying attention to differences from the first embodiment, the description of the same configuration as the first embodiment is omitted.

  As shown in FIG. 7A, a first through hole 25, a first heat transfer medium 30, an insulating film 31, and a P-type thermoelectric pattern 21P are formed in the first substrate 20. The structure in the middle of manufacturing is the same as the structure shown in FIG.

  As shown in FIG. 7B, a conductive film 26 is formed on the insulating film 31. The planar shape of the conductive film 26 is substantially the same as the combined shape of the N-type thermoelectric pattern 21N and the conductive film 22 shown in FIG. The conductive film 26 electrically connects the P-type thermoelectric patterns 21P adjacent to each other. For the conductive film 26, for example, the same conductive material as that of the conductive film 22 in FIG. 3F is used.

  As shown in FIG. 7C, the second substrate 40 is disposed on the first substrate 20, and the two are bonded together. An adhesive layer 50 and a second heat transfer medium 42 are formed on the second substrate 40. The second heat transfer medium 42 is positioned approximately in the middle of the first heat transfer medium 30 adjacent to each other, and is thermally coupled to the connection portion between the P-type thermoelectric pattern 21 </ b> P and the conductive film 26.

  In Example 3, a temperature difference can be efficiently generated at both ends of the P-type thermoelectric pattern 21P. An N-type thermoelectric pattern 21N may be used instead of the P-type thermoelectric pattern 21P.

  It may be difficult to prepare a P-type material and an N-type material with uniform characteristics using an oxide-based thermoelectric material. In addition, when the preferable film forming conditions are greatly different between the P-type material and the N-type material, it is difficult to form both on one substrate. In such a case, a configuration using only one of the P-type thermoelectric material and the N-type thermoelectric material as in Example 3 is effective.

  In the structure of the third embodiment, the number of manufacturing steps can be reduced as compared with the first and second embodiments. For this reason, manufacturing cost can be suppressed.

[Example 4]
A thermoelectric element according to Example 4 will be described with reference to FIGS. 8A to 8B. In the following description, paying attention to differences from the first embodiment, the description of the same configuration as the first embodiment is omitted.

  As shown in FIG. 8A, a plurality of truncated conical recesses 25 </ b> A are formed on the first surface 20 </ b> A of the first substrate 20. The diameter and the depth (the height of the truncated cone) of the opening surface (the bottom surface of the truncated cone) of the recess 25A are both about 150 μm. The concave portion 25A is formed using an ultraviolet laser, for example, a KrF excimer laser (wavelength 248 nm). By using the ultraviolet laser, the shape of the recess 25A can be controlled with high accuracy.

  As shown in FIG. 8B, the first through hole 25 is formed at the position where the recess 25A is formed. For example, a carbon dioxide laser drill or a mechanical drill can be used to form the first through hole 25. The diameter of the first through hole 25 is, for example, 100 μm. Subsequent steps are the same as those in the first embodiment.

  In Example 4, the taper shape of the opening of the first through hole 25 can be controlled with high accuracy. For this reason, disconnection or the like in the tapered portion is less likely to occur, and reliability and yield can be improved.

[Example 5]
With reference to FIG. 9A-FIG. 9C, the thermoelectric element by Example 5 is demonstrated. In the following description, paying attention to differences from the first embodiment, the description of the same configuration as the first embodiment is omitted.

  As shown in FIG. 9A, a first heat transfer medium 30, an insulating film 31, a P-type thermoelectric pattern 21P, an N-type thermoelectric pattern 21N, and a conductive film 22 are formed on the first substrate 20. The structure in the middle of manufacturing shown in FIG. 9A is the same as the structure shown in FIG.

  As shown in FIG. 9B, the insulating film 31, the P-type thermoelectric pattern 21P, the N-type thermoelectric pattern 21N, and the conductive film 22 are covered with an insulating film 33. For the insulating film 33, for example, an insulating material such as silicon oxide or silicon nitride is used. For example, sputtering is applied to form the insulating film 33. The thickness of the insulating film 33 is, for example, 0.1 μm. Note that an organic insulating material may be used for the insulating film 33. In the case where an organic insulating material is used, a spin coat method or the like can be applied to the formation of the insulating film 33.

  A second heat transfer medium 42 is formed on the insulating film 33. The second heat transfer medium 42 is disposed on the conductive film 22 located approximately in the middle of the first heat transfer media 30 adjacent to each other. The second heat transfer medium 42 is thermally coupled to the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N via the insulating film 33.

  Hereinafter, a method for forming the second heat transfer medium 42 will be described. Metal solder is formed on the insulating film 33 by using a mask having an opening in a region where the second heat transfer medium 42 is to be formed. By performing a heat treatment at about 250 ° C., the metal solder is once melted into a hemisphere. Thereby, the second heat transfer medium 42 is formed. Note that the second heat transfer medium 42 may have a truncated cone shape or a truncated pyramid shape.

  FIG. 10 shows a cross-sectional view of the thermoelectric element of Example 5 when in use. The outer surface of the first substrate 20 is in contact with the first heat source 55, and the top of the second heat transfer medium 42 is in contact with the second heat source 56. The second heat transfer medium 42 has the same function as the second heat transfer medium 42 shown in FIG. 1B of the first embodiment. One of the first heat source 55 and the second heat source 56 acts as a high-temperature side heat source, and the other acts as a low-temperature side heat source.

  In the fifth embodiment, a recess 20C is formed at a position where the first heat transfer medium 30 is disposed. Compared to the structure in which the recess 20C is not formed, the end portions of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N coupled to the first heat transfer medium 30 are separated from the second heat source 56, and the first heat source Approaching 55. Therefore, the ends of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N to be coupled to the first heat source 55 can be brought close to the temperature of the first heat source 55. Thereby, a temperature difference can be efficiently produced at both ends of the P-type thermoelectric pattern 21P and the N-type thermoelectric pattern 21N.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

20 First substrate 20A First surface 20B Second surface 20C Recess 21 Thermoelectric pattern 21P P-type thermoelectric pattern 21N N-type thermoelectric pattern 22 Conductive film 24 Electrode film 25 First through hole 26 Conductive film 30 First heat Transmission medium 30A First end face 30B Second end faces 31, 32, 33 Insulating film 40 Second substrate 40A First face 40C Recess 41 Second through hole 42 Second heat transfer medium 42A First end face 45 46 Cavity 50, 51 Adhesive layer 55 First heat source 56 Second heat source

Claims (5)

An insulating first substrate;
A first through hole formed in the first substrate;
A first end face disposed in a part of the first through hole and having a first end face facing the same direction as the first face at a position lower than the first face of the first substrate; A heat transfer medium;
A thermoelectric pattern comprising a thermoelectric material disposed on the first surface and thermally coupled to the first end surface of the first heat transfer medium;
A second heat transfer medium thermally coupled to the thermoelectric pattern at a position different from that of the first heat transfer medium and projecting in the opposite direction to the first heat transfer medium with respect to the thermoelectric pattern; Thermoelectric element. further,
An insulating second substrate disposed on the first surface of the first substrate and the thermoelectric pattern;
A second through hole formed in the second substrate and containing the second heat transfer medium;
The thermoelectric element according to claim 1, wherein a cavity is provided between the first heat transfer medium and the second substrate.   The thermoelectric element according to claim 2, wherein a cavity is provided between the second heat transfer medium and the first substrate. further,
A first through hole group formed of a plurality of through holes formed on the first substrate and disposed along the thermoelectric pattern;
A first end face located in a through hole belonging to the first through hole group and located in a position lower than the first face of the first substrate and facing the same direction as the first face; A first heat transfer medium group comprising a plurality of heat transfer media thermally coupled to the thermoelectric pattern;
A plurality of heat transfer media arranged along the thermoelectric pattern, thermally coupled to the thermoelectric pattern, and projecting in the opposite direction to the heat transfer media belonging to the first heat transfer media group with respect to the thermoelectric pattern. A second heat transfer medium group;
The first through hole is one through hole belonging to the first through hole group, and the first heat transfer medium is one heat transfer medium belonging to the first heat transfer medium group. The second heat transfer medium is one heat transfer medium belonging to the second heat transfer medium group,
The thermoelectric pattern includes a plurality of P-type thermoelectric patterns and N-type thermoelectric patterns alternately connected in series,
The heat transfer medium belonging to the first heat transfer medium group and the heat transfer medium belonging to the second heat transfer medium group are connected to the P-type thermoelectric pattern and the N-type thermoelectric pattern at the thermoelectric pattern. A heat transfer medium belonging to the first heat transfer medium group is thermally coupled to one end of each of the N-type thermoelectric pattern and the P-type thermoelectric pattern, The thermoelectric element according to any one of claims 1 to 3, wherein a heat transfer medium belonging to the second heat transfer medium group is thermally coupled to an end of the heat transfer medium. Forming a plurality of first through holes in an insulating first substrate;
A part of the inside of each of the first through holes is filled with a first heat transfer medium, and the first heat transfer medium is disposed at a position lower than one first surface of the first substrate. Arranging the end face of
Forming a thermoelectric pattern thermally coupled to the first heat transfer medium on the first surface;
A method of manufacturing a thermoelectric element, comprising: thermally coupling a second heat transfer medium to the thermoelectric pattern at a position different from the first heat transfer medium.

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