【０００１】
【発明の属する技術分野】
本発明は熱電半導体装置に関する。
【０００２】
【従来の技術】
図４は従来一般的に製造されている熱電半導体装置の斜視説明図である。熱電半導体装置は、基板１２、１３に設けられた電極１２ａ、１３ａと熱電半導体１１を半田材で接合し、Ｐ型熱電半導体とＮ型熱電半導体が交互に電気的に直列に接続された熱電半導体接続体１００を作製することによって製造される。
【０００３】
熱電半導体装置の使用時には、吸熱側の基板は温度が低いので熱収縮し、放熱側の基板は温度が高いので熱膨張するため熱電半導体に曲げ応力・せん断応力などが生じる。熱電半導体や半田層は機械的強度が低く、最も応力の加わる半田層や熱電半導体の電極との接合部付近に破損が生じ熱電半導体装置の信頼性を低下するなどの問題があった（非特許文献１など）。このような問題を解決する従来技術として、非特許文献１には、電極に凸部を設け、この凸部上に熱電半導体を接合した熱電半導体が開示されている。これにより応力が緩和され信頼性が向上するとされている。
【０００４】
【非特許文献１】
熱電変換工学、株式会社リアライズ社発行、３４５〜３４７ページ、４２５〜４２６ページ
【０００５】
【発明が解決しようとする課題】
しかしながら、従来技術のような構造でも熱電半導体と電極の接合部付近に応力が集中するため、機械的強度の弱い熱電半導体に破損が生じるなどの問題があった。
【０００６】
本発明は上記課題を解決したもので、信頼性に優れた熱電半導体装置を提供する。
【０００７】
【課題を解決するための手段】
上記技術的課題を解決するために、本発明の請求項１において講じた技術的手段（以下、第１の技術的手段と称する。）は、第１の第１電極と、該第１の第１電極にその一方面が接合された第１導電型熱電半導体と、該第１導電型熱電半導体の他方面に接合された第２電極と、該第２電極にその一方面が接合された第２導電型熱電半導体と、該第２導電型熱電半導体の他方面に接合された第２の第１電極が設けられ、前記第１の第１電極と前記第１導電型熱電半導体、前記第１導電型熱電半導体と前記第２電極、前記第２電極と前記第２導電型熱電半導体、前記第２導電型熱電半導体と前記第２の第１電極、の少なくとも一つは支持部材を介して接合されていることを特徴とする熱電半導体装置である。
【０００８】
上記第１の技術的手段による効果は、以下のようである。
【０００９】
すなわち、熱電半導体と電極を支持部材を介して接合することにより、熱電半導体と電極の接合付近に加わっていた最大応力が、熱電半導体と支持部材の接合部付近および支持部材と電極の接合部付近に分散され、熱電半導体と電極の接合付近に加わっていた最大応力が低減されるので、信頼性に優れた熱電半導体装置ができる。
【００１０】
上記技術的課題を解決するために、本発明の請求項２において講じた技術的手段（以下、第２の技術的手段と称する。）は、前記第１の第１電極と前記第１導電型熱電半導体、前記第１導電型熱電半導体と前記第２電極、前記第２電極と前記第２導電型熱電半導体、前記第２導電型熱電半導体と前記第２の第１電極、のすべてが支持部材を介して接合されていることを特徴とする請求項１記載の熱電半導体装置である。
【００１１】
上記第２の技術的手段による効果は、以下のようである。
【００１２】
すなわち、熱電半導体と電極がすべて支持部材を介して接合されているので、さらに最大応力を低減でき、より信頼性に優れた熱電半導体装置ができる。
上記技術的課題を解決するために、本発明の請求項３において講じた技術的手段（以下、第３の技術的手段と称する。）は、前記接合が半田付けによるものであることを特徴とする請求項１または２に記載の熱電半導体装置である。
【００１３】
上記第３の技術的手段による効果は、以下のようである。
【００１４】
すなわち、半田付けによって接合しているので、大きな設備を必要とせずに製造できる。
【００１５】
上記技術的課題を解決するために、本発明の請求項４において講じた技術的手段（以下、第４の技術的手段と称する。）は、前記第１導電型熱電半導体と前記支持部材、前記第２導電型熱電半導体と前記支持部材の少なくとも一方の支持部材は前記第１導電型熱電半導体または前記第２導電型熱電半導体にメッキ法によって形成されたものであることを特徴とする請求項１または２に記載の熱電半導体装置である。
【００１６】
上記第４の技術的手段による効果は、以下のようである。
【００１７】
すなわち、支持部材が熱電半導体にメッキ法で形成されたものであるので、平板状の熱電半導体の平面に支持部材を形成後、切断することによって支持部材が形成された熱電半導体を製造できるため、低コストで支持部材付き熱電半導体装置を製造できる。
【００１８】
【発明の実施の形態】
以下、本発明の実施例について、図面に基づいて説明する。
【００１９】
（実施例１）
図１は実施例１の熱電半導体装置の断面説明図である。１および２はセラミックス（酸化アルミニウム）製の基板である。基板１および２にはそれぞれ電極５および６が設けられている。電極５および６はメッキ法によって形成されている。電極５および６には、それぞれ支持部材７および８が半田層２１および２２によって接合されている。支持部材７および８の間には、半田層２３、２４によって支持部材７、８と接合された第１導電型熱電半導体であるＮ型熱電半導体３または第２導電型熱電半導体であるＰ型熱電半導体４が設けられている。
【００２０】
すなわち、第１の第１電極５１に支持部材７１の一方面が半田層２１によって接合されている。支持部材７１の他方面にＮ型熱電半導体３の一方面が半田層２３によって接合されている。Ｎ型熱電半導体３の他方面に支持部材８１の一方面が半田層２４によって接合されている。支持部材８１の他方面は半田層２２によって第２電極６に接合されている。第２電極６の支持部材８１と同じ面側には、もう一つの支持部材８２の一方面が半田層２２によって接合されている。支持部材８２の他方面にＰ型熱電半導体４の一方面が半田層２４によって接合されている。Ｐ型熱電半導体４の他方面に支持部材７２の一方面が半田層２３によって接合されている。支持部材７２の他方面に第２の第１電極５２が接合されている。
【００２１】
この構造の熱電半導体装置についてＦＥＭ（有限要素法）解析を実施した。ＦＥＭ解析を実施した熱電半導体装置の外形寸法は縦８ｍｍ、横１２ｍｍ、高さ１．３５ｍｍである。Ｎ型熱電半導体３およびＰ型熱電半導体４の大きさは０．５５ｍｍ四方、高さ０．４ｍｍの直方体で、高さ方向の一方面と他方面に支持部材７または支持部材８が接合されている。Ｎ型熱電半導体３、Ｐ型熱電半導体４の個数はそれぞれ７０個である。熱電半導体装置の縦方向には１４個、横方向には１０個の熱電半導体が並んでいる。すなわち、基板１上に熱電半導体は１４個×１０個の行列配置されている。支持部材７１、７２、８１、８２の大きさは０．５５ｍｍ四方、高さ０．１５ｍｍの直方体で、高さ方向の一方面と他方面に熱電半導体または電極が接合されている。電極５（電極５１、５２）、電極６の大きさは幅０．６ｍｍ、長さ１．４ｍｍ、厚さ０．０８ｍｍで、同じ面側の長さ方向の一方と他方に熱電半導体が接合されている。基板１、２は縦８ｍｍ、横１２ｍｍ、厚さ０．３ｍｍである。半田層２１〜２４の幅と長さは電極５、６と同じで、厚さは１５μｍである。
【００２２】
第１の第１電極５１、第２の第１電極５２、第２電極６の材質は銅（Ｃ１０２０）であり、そのヤング率は１１７ＧＰａ、ポアソン比０．３３である。半田層２１〜２４の材質はＳｎ／Ｐｂ半田であり、そのヤング率は３４．５ＧＰａ、ポアソン比０．４である。支持部材７１、７２、８１、８２の材質は電極と同じ銅（Ｃ１０２０）である。境界条件として、基板１の温度を２５℃、基板２の温度を７０℃、第１の第１電極５１、第２の第１電極５２および支持部材７１、７２の温度を２５℃、第２電極６および支持部材８１、８２の温度を７５℃とした。またＮ型熱電半導体３およびＰ型熱電半導体４は、第１電極側の温度を２５℃から第２電極側の温度を７５℃に徐変しているとした。
【００２３】
（実施例２）
図２は実施例２の熱電半導体装置の断面説明図である。実施例２は、支持部材および支持部材と熱電素子の接合方法が異なる以外、実施例１と同様の構成であるので同じ部位には同じ符号を付し説明を省略する。支持部材７３と８３は、それぞれＮ型熱電半導体３の一方面と他方面に銅をメッキすることにより形成されたものである。支持部材７４と８４は、それぞれＰ型熱電半導体４の一方面と他方面に銅をメッキすることにより形成されたものである。
【００２４】
実施例２の熱電半導体装置は、まずＮ型熱電半導体３、Ｐ型熱電半導体４に銅メッキ法により支持部材７３、７４、８３、８４を形成する。支持部材が形成されたＮ型熱電半導体３、Ｐ型熱電半導体４を半田層２１により基板１に形成された電極５と接合し、半田層２２により基板２に形成された電極６と接合する。
【００２５】
支持部材７３、７４、８３、８４の大きさは０．５５ｍｍ四方、高さ０．１５ｍｍの直方体で、０．５５ｍｍ四方の一方面が熱電半導体に当接している。支持部材７３、７４、８３、８４の材質は銅（Ｃ１０２０）であり、そのヤング率は１１７ＧＰａ、ポアソン比０．３３である。その他の部材の形状、材質は実施例１と同じである。境界条件は実施例１と同じとした。この構造の熱電半導体装置についてＦＥＭ解析を実施した。
【００２６】
（比較例）
図３は比較例の熱電半導体装置の断面説明図である。比較例は非特許文献１の第４２６ページ、図３〜５に記載された熱電半導体装置を模したものである。比較例の電極３１、３２の形状は幅０．６ｍｍ、長さ１．４ｍｍ、厚さ０．２３ｍｍの長さ方向の中央に幅０．６ｍｍ、長さ０．２ｍｍ、深さ０．１５ｍｍの凹部を有する凹形状である。基板１上に電極３１が形成され、この電極３１とＮ型熱電半導体３またはＰ型熱電半導体４の一方面が半田層２１により接合されている。Ｎ型熱電半導体３またはＰ型熱電半導体４の他方面は基板２上に形成された電極３２と半田層２２により接合されている。
【００２７】
電極３１、３２の材質は実施例１の電極と同じ銅（Ｃ１０２０）である。基板１、２、Ｎ型熱電半導体３、Ｐ型熱電半導体４、半田層２１、２２の形状と材質は実施例１と同じである。境界条件は実施例１と同じとした。この構造の熱電半導体装置についてＦＥＭ解析を実施した。
【００２８】
（解析結果）
ＦＥＭ解析の結果から得られた実施例１、２および比較例の最大応力を表１に示す。
【００２９】
【表１】
実施例１、２は比較例に比べて最大応力が約１／２となっている。実施例１の応力集中部位は熱電半導体と支持部材の接合部付近および支持部材と電極の接合部付近であった。実施例２の応力集中部位は熱電半導体と支持部材の界面付近および支持部材と電極の接合部付近であった。比較例の応力集中部位は熱電半導体と電極の接合部付近であった。これらの応力集中部位にかかる応力が表１の最大応力となっている。比較例では１ヶ所に応力集中するのに対し、実施例１、２では応力集中が２ヶ所に分散している。この結果、最大応力が半減したと考えられる。
【００３０】
以上のように、熱電半導体と電極を支持部材を介して接合することにより、熱電半導体と電極の接合付近に加わっていた最大応力は、熱電半導体と支持部材の接合部付近および支持部材と電極の接合部付近に分散され、熱電半導体と電極の接合付近に加わっていた最大応力が大きく低減されるので、信頼性に優れた熱電半導体装置ができる。
【００３１】
なお、支持部材と電極の接合部付近に応力集中が起こっても支持部材や電極の強度は大きいので、この部分では破壊されることはない。
【００３２】
実施例では第１電極と熱電半導体の間、第２電極と熱電半導体の間の両方に支持部材が設けられているが、その一方に設けてもよい。また第１の第１電極とＮ型熱電半導体の間、Ｎ型熱電半導体と第２電極の間、第２電極とＰ型熱電半導体の間、Ｐ型熱電半導体と第２の第１電極の間、のいずれかの間に支持部材が設けられている場合にも適用できる。この場合は、基板１と基板２は略平行であることが望ましいので、電極や熱電半導体の高さで調整する。
【００３３】
実施例では支持部材に銅（Ｃ１０２０）を用いたが、特に限定されず、電気伝導性を有し、良熱伝導の材料なら使用できる。支持部材としては電極のヤング率以下のヤング率の材質を使用した方が応力緩和効果が大きいために望ましい。また支持部材としては熱電半導体より小さいヤング率の材質を使用した方が応力緩和効果がさらに大きいために望ましい。すなわち支持部材のヤング率は低い方が好ましく、スズ（ヤング率４９．９ＧＰａ）などが例示できる。
【００３４】
実施例では半田層の材質としてＳｎ／Ｓｂ半田を用いたが、接合限定されない。半田層は他の部材の厚さに比べて極めて薄いので、その材質は大きな影響を与えない。実施例では半田層またはメッキ法による直接接合を用いたが、他の接合方法も適宜選択できる。
【００３５】
実施例では第１導電型熱電半導体をＮ型熱電半導体とし、第２導電型熱電半導体をＰ型熱電半導体としたが、第１導電型熱電半導体をＰ型熱電半導体とし、第２導電型熱電半導体をＮ型熱電半導体としてもよい。
【００３６】
【発明の効果】
本発明は、第１の第１電極と、該第１の第１電極にその一方面が接合された第１導電型熱電半導体と、該第１導電型熱電半導体の他方面に接合された第２電極と、該第２電極にその一方面が接合された第２導電型熱電半導体と、該第２導電型熱電半導体の他方面に接合された第２の第１電極が設けられ、前記第１の第１電極と前記第１導電型熱電半導体、前記第１導電型熱電半導体と前記第２電極、前記第２電極と前記第２導電型熱電半導体、前記第２導電型熱電半導体と前記第２の第１電極、の少なくとも一つは支持部材を介して接合されていることを特徴とする熱電半導体装置であるので、信頼性に優れた熱電半導体装置ができる。
【図面の簡単な説明】
【図１】実施例１の熱電半導体装置の断面説明図
【図２】実施例２の熱電半導体装置の断面説明図
【図３】比較例の熱電半導体装置の断面説明図
【図４】従来一般的に製造されている熱電半導体装置の斜視説明図
【符号の説明】
１、２…基板
３…Ｎ型熱電半導体（第１導電型熱電半導体）
４…Ｐ型熱電半導体（第２導電型熱電半導体）
５、３１…第１電極
６、３２…第２電極
７、８、７１〜７４、８１〜８４…支持部材
２１〜２４…半田層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thermoelectric semiconductor device.
[0002]
[Prior art]
FIG. 4 is an explanatory perspective view of a thermoelectric semiconductor device generally manufactured conventionally. The thermoelectric semiconductor device is a thermoelectric semiconductor in which electrodes 12a and 13a provided on substrates 12 and 13 and thermoelectric semiconductor 11 are joined by a solder material, and a P-type thermoelectric semiconductor and an N-type thermoelectric semiconductor are alternately electrically connected in series. It is manufactured by manufacturing the connection body 100.
[0003]
When the thermoelectric semiconductor device is used, the heat-absorbing substrate has a low temperature and therefore contracts thermally, and the heat-radiating substrate has a high temperature and thermally expands, so that bending stress and shear stress are generated in the thermoelectric semiconductor. Thermoelectric semiconductors and solder layers have low mechanical strength, and there are problems such as damage to the solder layers to which the most stress is applied and the vicinity of the junction between the thermoelectric semiconductor and the electrodes, thereby reducing the reliability of the thermoelectric semiconductor device (non-patented). Reference 1). As a conventional technique for solving such a problem, Non-Patent Document 1 discloses a thermoelectric semiconductor in which a convex portion is provided on an electrode, and a thermoelectric semiconductor is bonded on the convex portion. It is said that the stress is relieved and the reliability is improved.
[0004]
[Non-patent document 1]
Thermoelectric conversion engineering, published by Realize Inc., pages 345-347, 425-426
[Problems to be solved by the invention]
However, even in the structure of the related art, since stress concentrates near the junction between the thermoelectric semiconductor and the electrode, there has been a problem that the thermoelectric semiconductor having low mechanical strength is damaged.
[0006]
The present invention has solved the above problems and provides a thermoelectric semiconductor device having excellent reliability.
[0007]
[Means for Solving the Problems]
In order to solve the above technical problem, the technical means (hereinafter referred to as first technical means) taken in claim 1 of the present invention comprises a first first electrode and a first first electrode. A first conductive type thermoelectric semiconductor having one surface bonded to one electrode, a second electrode bonded to the other surface of the first conductive type thermoelectric semiconductor, and a second electrode having one surface bonded to the second electrode. A second conductivity type thermoelectric semiconductor; and a second first electrode joined to the other surface of the second conductivity type thermoelectric semiconductor. The first first electrode, the first conductivity type thermoelectric semiconductor, and the first At least one of a conductivity type thermoelectric semiconductor and the second electrode, the second electrode and the second conductivity type thermoelectric semiconductor, or the second conductivity type thermoelectric semiconductor and the second first electrode are joined via a support member. A thermoelectric semiconductor device characterized in that:
[0008]
The effects of the first technical means are as follows.
[0009]
That is, by joining the thermoelectric semiconductor and the electrode via the support member, the maximum stress applied near the joint between the thermoelectric semiconductor and the electrode is increased near the joint between the thermoelectric semiconductor and the support member and near the joint between the thermoelectric semiconductor and the electrode. And the maximum stress applied near the junction between the thermoelectric semiconductor and the electrode is reduced, so that a thermoelectric semiconductor device with excellent reliability can be obtained.
[0010]
In order to solve the above technical problem, the technical means (hereinafter referred to as second technical means) taken in claim 2 of the present invention includes the first first electrode and the first conductivity type. The thermoelectric semiconductor, the first conductivity type thermoelectric semiconductor and the second electrode, the second electrode and the second conductivity type thermoelectric semiconductor, and the second conductivity type thermoelectric semiconductor and the second first electrode are all support members. The thermoelectric semiconductor device according to claim 1, wherein the thermoelectric semiconductor device is joined through a junction.
[0011]
The effects of the second technical means are as follows.
[0012]
That is, since the thermoelectric semiconductor and the electrodes are all joined via the support member, the maximum stress can be further reduced, and a thermoelectric semiconductor device with higher reliability can be obtained.
In order to solve the above technical problem, a technical means (hereinafter referred to as a third technical means) taken in claim 3 of the present invention is characterized in that the joining is performed by soldering. The thermoelectric semiconductor device according to claim 1 or 2, wherein
[0013]
The effects of the third technical means are as follows.
[0014]
That is, since they are joined by soldering, they can be manufactured without requiring large equipment.
[0015]
In order to solve the above technical problem, the technical means (hereinafter referred to as fourth technical means) taken in claim 4 of the present invention includes the first conductive type thermoelectric semiconductor, the supporting member, 2. The thermoelectric semiconductor according to claim 1, wherein at least one of the second conductive thermoelectric semiconductor and the support member is formed by plating the first conductive thermoelectric semiconductor or the second conductive thermoelectric semiconductor. Or the thermoelectric semiconductor device according to 2.
[0016]
The effects of the fourth technical means are as follows.
[0017]
That is, since the support member is formed by plating the thermoelectric semiconductor, the support member is formed on the plane of the flat thermoelectric semiconductor, and the thermoelectric semiconductor having the support member formed can be manufactured by cutting. A thermoelectric semiconductor device with a supporting member can be manufactured at low cost.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
(Example 1)
FIG. 1 is an explanatory cross-sectional view of the thermoelectric semiconductor device according to the first embodiment. 1 and 2 are substrates made of ceramics (aluminum oxide). Substrates 1 and 2 are provided with electrodes 5 and 6, respectively. The electrodes 5 and 6 are formed by a plating method. Support members 7 and 8 are joined to the electrodes 5 and 6 by solder layers 21 and 22, respectively. Between the support members 7 and 8, the N-type thermoelectric semiconductor 3 as the first conductivity type thermoelectric semiconductor or the P-type thermoelectric semiconductor as the second conductivity type thermoelectric semiconductor joined to the support members 7 and 8 by the solder layers 23 and 24. A semiconductor 4 is provided.
[0020]
That is, one surface of the support member 71 is joined to the first first electrode 51 by the solder layer 21. One surface of the N-type thermoelectric semiconductor 3 is joined to the other surface of the support member 71 by the solder layer 23. One surface of the support member 81 is joined to the other surface of the N-type thermoelectric semiconductor 3 by the solder layer 24. The other surface of the support member 81 is joined to the second electrode 6 by the solder layer 22. One surface of another support member 82 is joined to the second electrode 6 on the same surface side as the support member 81 by the solder layer 22. One surface of the P-type thermoelectric semiconductor 4 is joined to the other surface of the support member 82 by the solder layer 24. One surface of the support member 72 is joined to the other surface of the P-type thermoelectric semiconductor 4 by the solder layer 23. The second first electrode 52 is joined to the other surface of the support member 72.
[0021]
FEM (finite element method) analysis was performed on the thermoelectric semiconductor device having this structure. The external dimensions of the thermoelectric semiconductor device subjected to the FEM analysis are 8 mm in length, 12 mm in width, and 1.35 mm in height. Each of the N-type thermoelectric semiconductor 3 and the P-type thermoelectric semiconductor 4 is a rectangular parallelepiped having a size of 0.55 mm square and a height of 0.4 mm, and a supporting member 7 or a supporting member 8 is joined to one surface and the other surface in the height direction. I have. The number of the N-type thermoelectric semiconductors 3 and the number of the P-type thermoelectric semiconductors 4 are 70 each. Fourteen thermoelectric semiconductors are arranged in the vertical direction and ten thermoelectric semiconductors in the horizontal direction of the thermoelectric semiconductor device. That is, the thermoelectric semiconductors are arranged in a matrix of 14 × 10 on the substrate 1. Each of the support members 71, 72, 81, and 82 is a rectangular solid having a size of 0.55 mm square and a height of 0.15 mm, and a thermoelectric semiconductor or an electrode is joined to one surface and the other surface in the height direction. Electrodes 5 (electrodes 51 and 52) and electrode 6 have a width of 0.6 mm, a length of 1.4 mm, and a thickness of 0.08 mm, and a thermoelectric semiconductor is joined to one and the other in the length direction on the same surface side. ing. The substrates 1 and 2 are 8 mm long, 12 mm wide, and 0.3 mm thick. The width and length of the solder layers 21 to 24 are the same as those of the electrodes 5 and 6, and the thickness is 15 μm.
[0022]
The material of the first first electrode 51, the second first electrode 52, and the second electrode 6 is copper (C1020), and its Young's modulus is 117 GPa and Poisson's ratio is 0.33. The material of the solder layers 21 to 24 is Sn / Pb solder, and its Young's modulus is 34.5 GPa and Poisson's ratio is 0.4. The material of the support members 71, 72, 81, 82 is the same copper (C1020) as the electrodes. As boundary conditions, the temperature of the substrate 1 is 25 ° C., the temperature of the substrate 2 is 70 ° C., the temperatures of the first first electrode 51, the second first electrode 52, and the supporting members 71 and 72 are 25 ° C., and the second electrode 6 and the temperature of the supporting members 81 and 82 were set to 75 ° C. The N-type thermoelectric semiconductor 3 and the P-type thermoelectric semiconductor 4 are assumed to gradually change the temperature on the first electrode side from 25 ° C. to 75 ° C. on the second electrode side.
[0023]
(Example 2)
FIG. 2 is an explanatory cross-sectional view of the thermoelectric semiconductor device according to the second embodiment. The second embodiment has the same configuration as that of the first embodiment except that the supporting member and the method of bonding the supporting member and the thermoelectric element are different. The support members 73 and 83 are formed by plating copper on one surface and the other surface of the N-type thermoelectric semiconductor 3, respectively. The support members 74 and 84 are formed by plating copper on one surface and the other surface of the P-type thermoelectric semiconductor 4, respectively.
[0024]
In the thermoelectric semiconductor device according to the second embodiment, first, support members 73, 74, 83, and 84 are formed on the N-type thermoelectric semiconductor 3 and the P-type thermoelectric semiconductor 4 by a copper plating method. The N-type thermoelectric semiconductor 3 and the P-type thermoelectric semiconductor 4 on which the support members are formed are joined to the electrode 5 formed on the substrate 1 by the solder layer 21 and to the electrode 6 formed on the substrate 2 by the solder layer 22.
[0025]
Each of the support members 73, 74, 83, and 84 is a rectangular solid having a square of 0.55 mm and a height of 0.15 mm, and one surface of the square of 0.55 mm is in contact with the thermoelectric semiconductor. The material of the support members 73, 74, 83 and 84 is copper (C1020), and its Young's modulus is 117 GPa and Poisson's ratio is 0.33. The shape and material of the other members are the same as in the first embodiment. The boundary conditions were the same as in Example 1. FEM analysis was performed on the thermoelectric semiconductor device having this structure.
[0026]
(Comparative example)
FIG. 3 is an explanatory sectional view of a thermoelectric semiconductor device of a comparative example. The comparative example simulates the thermoelectric semiconductor device described in Non-Patent Document 1, page 426, and FIGS. The electrodes 31 and 32 of the comparative example have a width of 0.6 mm, a length of 1.4 mm, a thickness of 0.23 mm, a width of 0.6 mm, a length of 0.2 mm, and a depth of 0.15 mm at the center in the longitudinal direction. It has a concave shape having a concave portion. An electrode 31 is formed on the substrate 1, and the electrode 31 and one surface of the N-type thermoelectric semiconductor 3 or the P-type thermoelectric semiconductor 4 are joined by the solder layer 21. The other surface of the N-type thermoelectric semiconductor 3 or the P-type thermoelectric semiconductor 4 is joined to the electrode 32 formed on the substrate 2 by the solder layer 22.
[0027]
The material of the electrodes 31 and 32 is the same copper (C1020) as the electrode of the first embodiment. The shapes and materials of the substrates 1 and 2, the N-type thermoelectric semiconductor 3, the P-type thermoelectric semiconductor 4, and the solder layers 21 and 22 are the same as those in the first embodiment. The boundary conditions were the same as in Example 1. FEM analysis was performed on the thermoelectric semiconductor device having this structure.
[0028]
(Analysis result)
Table 1 shows the maximum stress of Examples 1 and 2 and Comparative Example obtained from the results of the FEM analysis.
[0029]
[Table 1]
In Examples 1 and 2, the maximum stress was about １ ／ compared to the comparative example. The stress concentration sites in Example 1 were near the junction between the thermoelectric semiconductor and the support member and near the junction between the support member and the electrode. The stress concentration sites in Example 2 were near the interface between the thermoelectric semiconductor and the support member and near the joint between the support member and the electrode. The stress concentration site of the comparative example was near the junction between the thermoelectric semiconductor and the electrode. The stress applied to these stress concentration portions is the maximum stress in Table 1. In the comparative example, the stress concentration is at one location, whereas in Examples 1 and 2, the stress concentration is dispersed at two locations. As a result, it is considered that the maximum stress was reduced by half.
[0030]
As described above, by joining the thermoelectric semiconductor and the electrode via the support member, the maximum stress applied near the junction between the thermoelectric semiconductor and the electrode is increased near the junction between the thermoelectric semiconductor and the support member and between the support member and the electrode. Since the maximum stress distributed near the junction and applied near the junction between the thermoelectric semiconductor and the electrode is greatly reduced, a highly reliable thermoelectric semiconductor device can be obtained.
[0031]
Note that even if stress concentration occurs near the joint between the support member and the electrode, the strength of the support member and the electrode is high, so that the portion is not destroyed.
[0032]
In the embodiment, the support members are provided both between the first electrode and the thermoelectric semiconductor and between the second electrode and the thermoelectric semiconductor, but may be provided on one of them. Further, between the first first electrode and the N-type thermoelectric semiconductor, between the N-type thermoelectric semiconductor and the second electrode, between the second electrode and the P-type thermoelectric semiconductor, between the P-type thermoelectric semiconductor and the second first electrode. The present invention can also be applied to a case where a supporting member is provided between any of the above. In this case, since it is desirable that the substrate 1 and the substrate 2 are substantially parallel, adjustment is made by the height of the electrodes and the thermoelectric semiconductor.
[0033]
In the embodiment, copper (C1020) is used for the support member. However, the material is not particularly limited, and any material having electric conductivity and good heat conductivity can be used. It is preferable to use a material having a Young's modulus equal to or less than the Young's modulus of the electrode because the stress relaxation effect is large. It is preferable to use a material having a Young's modulus smaller than that of the thermoelectric semiconductor as the support member because the stress relaxation effect is further increased. That is, the Young's modulus of the support member is preferably low, and tin (Young's modulus 49.9 GPa) can be exemplified.
[0034]
Although the Sn / Sb solder is used as the material of the solder layer in the embodiment, the joining is not limited. Since the solder layer is extremely thin compared to the thickness of the other members, its material does not have a significant effect. In the embodiment, the direct bonding by the solder layer or the plating method is used, but other bonding methods can be appropriately selected.
[0035]
In the embodiment, the first-conductivity-type thermoelectric semiconductor is an N-type thermoelectric semiconductor, and the second-conductivity-type thermoelectric semiconductor is a P-type thermoelectric semiconductor. May be an N-type thermoelectric semiconductor.
[0036]
【The invention's effect】
The present invention provides a first first electrode, a first conductive type thermoelectric semiconductor having one surface joined to the first first electrode, and a first conductive type thermoelectric semiconductor joined to the other surface of the first conductive type thermoelectric semiconductor. A second conductive type thermoelectric semiconductor having one surface bonded to the second electrode, and a second first electrode bonded to the other surface of the second conductive type thermoelectric semiconductor; A first electrode and the first conductivity type thermoelectric semiconductor, the first conductivity type thermoelectric semiconductor and the second electrode, the second electrode and the second conductivity type thermoelectric semiconductor, the second conductivity type thermoelectric semiconductor and the second Since at least one of the second electrodes is a thermoelectric semiconductor device that is joined via a support member, a thermoelectric semiconductor device with excellent reliability can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a thermoelectric semiconductor device according to a first embodiment; FIG. 2 is a cross-sectional view of a thermoelectric semiconductor device according to a second embodiment; FIG. 3 is a cross-sectional view of a thermoelectric semiconductor device according to a comparative example; Explanatory view of a thermoelectric semiconductor device manufactured in a typical manner [Description of reference numerals]
1, 2, substrate 3, N-type thermoelectric semiconductor (first conductivity type thermoelectric semiconductor)
4. P-type thermoelectric semiconductor (second conductivity type thermoelectric semiconductor)
5, 31 first electrodes 6, 32 second electrodes 7, 8, 71 to 74, 81 to 84 support members 21 to 24 solder layer
