JP2004163196A

JP2004163196A - Package for pressure detecting device

Info

Publication number: JP2004163196A
Application number: JP2002327811A
Authority: JP
Inventors: Koji Kinomura; 浩司木野村
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2002-11-12
Filing date: 2002-11-12
Publication date: 2004-06-10

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small pressure detecting device having high sensitivity that can accurately detect external pressure. <P>SOLUTION: In this package for the pressure detecting device, a first electrode 7 for forming electrostatic capacity is installed on one main surface of an insulating base substrate 1, on which a semiconductor element 3 is mounted on the other main surface, and an insulating plate 2 having a second electrode 9 facing the first electrode 7 on the inside main surface is joined in a flexible state to the substrate 1 so as to form a sealed space between the one main surface of the substrate 1 and the insulating plate 2. The first electrode 7 is formed being attached to the whole surface of a region where the one main surface is exposed to the inside of the sealed space. The second electrode 9 is formed being attached to the center part of a region where the inside main surface of the insulating plate 2 is exposed to the inside of the sealed space, approximately into the shape of a circle having a diameter equal to 50-80% of the diameter of the region. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、圧力を検出するための圧力検出装置に使用される圧力検出装置用パッケージに関する。
【０００２】
【従来の技術】
従来、圧力を検出するための圧力検出装置として静電容量型の圧力検出装置が知られている。この静電容量型の圧力検出装置は、図４に断面図で示すように、セラミックス材料や樹脂材料から成る配線基板２１上に、静電容量型の感圧素子２２と、パッケージ２８に収容された演算用の半導体素子２９とを備えている（特許文献１参照）。
【０００３】
そして、感圧素子２２は、例えばセラミックス材料等の電気絶縁材料から成り、上面中央部に静電容量形成用の一方の電極２３が被着された凹部を有する絶縁基体２４と、この絶縁基体２４の上面に絶縁基体２４との間に密閉空間を形成するようにして可撓な状態で接合され、下面に静電容量形成用の他方の電極２５が被着された絶縁板２６と、各静電容量形成用の電極２３・２５をそれぞれ外部に電気的に接続するための外部リード端子２７とから構成されており、外部の圧力に応じて絶縁板２６が撓むことにより各静電容量形成用の電極２３・２５間に形成される静電容量が変化する。そして、この静電容量の変化を演算用の半導体素子２９により演算処理することにより外部の圧力を検出することができる。
【０００４】
しかしながら、この従来の圧力検出装置によると、感圧素子２２と半導体素子２９とを配線基板２１上に個別に実装していることから、圧力検出装置が大型化してしまうとともに圧力検出用の電極２３・２５と半導体素子２９との間の配線が長いものとなり、この長い配線間に不要な静電容量が形成されるため感度が低いという問題点を有していた。
【０００５】
そこで、上記特許文献１の図３に示すように、一方の主面に半導体素子１３が搭載される搭載部１１ｂを有する絶縁基体１１と、この絶縁基体１１の表面および内部に配設され、半導体素子１３の各電極が電気的に接続される複数の配線導体１５と、絶縁基体１１の他方の主面の中央部に被着され、配線導体１５の一つに電気的に接続された静電容量形成用の第一電極１７と、絶縁基体１１の他方の主面に、この主面の中央部との間に密閉空間を形成するように可撓な状態で接合された絶縁板１２と、この絶縁板１２の内側主面に第一電極１７と対向して被着され、配線導体１５の他の一つに電気的に接続された静電容量形成用の第二電極１９とを具備する圧力検出装置用パッケージを提案した。この圧力検出用パッケージによると、一方の主面に半導体素子１３が搭載される搭載部１１ｂを有する絶縁基体１１の他方の主面に静電容量形成用の第一電極１７を設けるとともに、この第一電極１７に対向する静電容量形成用の第二電極１９を内側面に有する絶縁板１２を、絶縁基体１５の他方の主面との間に密閉空間を形成するようにして可撓な状態で接合させたことから、半導体素子１３を収容するパッケージに感圧素子が一体に形成され、その結果、圧力検出装置を小型とすることができるとともに圧力検出用の電極と半導体素子１３とを接続する配線を短いものとして、これらの配線間に発生する不要な静電容量を小さなものとすることができる。
【０００６】
なお、上記特許文献１の圧力検出装置用パッケージによると、第一電極１７、第二電極１９が、それぞれ絶縁基体１１の他方の主面および絶縁板１２の内側主面が密閉空間内に露出する領域の略全面にわたって被着形成されていた。
【０００７】
【特許文献１】
特開２００１−３５６０６４号公報（第２頁、図３、図４）
【０００８】
【発明が解決しようとする課題】
しかしながら、上記特許文献１の圧力検出装置用パッケージによると、第一電極１７、第二電極１９が、それぞれ絶縁基体１１の他方の主面および絶縁板１２の内側主面が密閉空間内に露出する領域の略全面にわたって被着形成されていることから、第一電極１７と第二電極１９との間に形成される静電容量は大きくなり、このパッケージに圧力が印加された場合に絶縁板１２の密閉空間に対応する領域の中央部は大きく変位するものの外周部の変位は極めて小さいので、第一電極１７および第二電極１９の外周部は静電容量の変化にはあまり寄与することが無く、むしろ第一電極１７と第二電極１９との間の静電容量の変化率が小さいものとなり、圧力の検出感度が低下してしまうという問題点を有していた。
【０００９】
本発明はかかる上述の問題点に鑑み案出されたものであり、その目的は、小型でかつ感度が高く、外部の圧力を正確に検出することが可能な圧力検出装置を提供することにある。
【００１０】
【課題を解決するための手段】
本発明の圧力検出装置用パッケージは、一方の主面に半導体素子が搭載される搭載部を有する絶縁基体と、該絶縁基体の表面および内部に配設され、前記半導体素子の各電極が電気的に接続される複数の配線導体と、前記絶縁基体の他方の主面との間に略円板形状の密閉空間を形成するように可撓な状態で前記絶縁基体に接合された絶縁板と、前記密閉空間内の前記絶縁基体の前記他方の主面に被着され、前記配線導体の一つに電気的に接続された静電容量形成用の第一電極と、前記絶縁板の内側主面に前記第一電極と対向するように被着され、前記配線導体の他の一つに電気的に接続された静電容量形成用の第二電極とを具備する圧力検出装置用パッケージであって、前記第一電極は、前記他方の主面が前記密閉空間内に露出する領域の全面に被着形成されており、前記第二電極は、前記内側主面が前記密閉空間内に露出する領域の中心部に該領域の直径に対して５０〜８０％の直径を有する略円形の形状に被着形成されていることを特徴とするものである。
【００１１】
本発明の圧力検出装置用パッケージによれば、第一電極は絶縁基体の他方の主面が密閉空間内に露出する領域の全面に被着形成されており、第二電極は絶縁板の内側主面が密閉空間内に露出する領域の中心部に、その領域の直径に対して５０〜８０％の直径を有する略円形の形状に被着形成されていることから、第一電極と第二電極との外周部に第一電極と第二電極との重なりから成る圧力検出部はなく、そのため第一電極と第二電極の外周部に静電容量の変化にあまり寄与することのない余計な静電容量が形成されることはなく、かつ第二電極は絶縁板の中心部に形成されており絶縁板の中心部は大きく変位するので、外部の圧力を感度良く検出することができる圧力検出装置用パッケージとすることができる。
【００１２】
【発明の実施の形態】
次に、本発明の圧力検出装置用パッケージを添付の図面に基づき詳細に説明する。図１は、本発明の圧力検出装置用パッケージの実施の形態の一例を示す断面図であり、図中、１は絶縁基体、２は絶縁板、３は半導体素子である。
【００１３】
絶縁基体１は、酸化アルミニウム質焼結体や窒化アルミニウム質焼結体・ムライト質焼結体・炭化珪素質焼結体・窒化珪素質焼結体・ガラス−セラミックス等の電気絶縁材料から成る積層体であり、例えば酸化アルミニウム質焼結体から成る場合であれば、酸化アルミニウム・酸化珪素・酸化マグネシウム・酸化カルシウム等のセラミック原料粉末に適当な有機バインダ・溶剤・可塑剤・分散剤を添加混合して泥漿状となすとともにこれを従来周知のドクタブレード法を採用してシート状に成形することにより複数枚のセラミックグリーンシートを得、しかる後、これらのセラミックグリーンシートに適当な打ち抜き加工・積層加工・切断加工を施すことにより絶縁基体１用の生セラミック成形体を得るとともにこの生セラミック成形体を約１６００℃の温度で焼成することにより製作される。
【００１４】
絶縁基体１は、その下面中央部に半導体素子３を収容するための凹部１ａが形成されており、これにより半導体素子３を収容する容器として機能する。そして、この凹部１ａの底面中央部が半導体素子３が搭載される搭載部１ｂとなっており、この搭載部１ｂに半導体素子３を搭載するとともに凹部１ａ内に例えばエポキシ樹脂等の樹脂製封止材４を充填することにより半導体素子３が封止される。なお、この例では半導体素子３は樹脂製封止材４を凹部１ａ内に充填することにより封止されるが、半導体素子３は絶縁基体１の下面に金属やセラミックスから成る蓋体を凹部１ａを塞ぐように接合させることにより封止されてもよい。
【００１５】
また、搭載部１ｂには半導体素子３の各電極と接続される複数の配線導体５が導出しており、この配線導体５と半導体素子３の各電極を半田バンプ６等の導電性材料から成る導電性接合部材を介して接合することにより半導体素子３の各電極と各配線導体５とが電気的に接続されるとともに半導体素子３が搭載部１ｂに固定される。なお、この例では、半導体素子３の電極と配線導体５とは半田バンプ６を介して接続されるが、半導体素子３の電極と配線導体５とはボンディングワイヤ等の他の種類の電気的接続手段により接続されてもよい。
【００１６】
配線導体５は、半導体素子３の各電極を外部電気回路および後述する第一電極７・第二電極９に電気的に接続するための導電路として機能し、その一部は絶縁基体１の外周下面に導出し、別の一部は第一電極７・第二電極９に電気的に接続されている。そして、半導体素子３の各電極をこれらの配線導体５に導電性接合材６を介して電気的に接続するとともに半導体素子３を樹脂製封止材４で封止した後、配線導体５の絶縁基体１外周下面に導出した部位を外部電気回路基板の配線導体に半田等の導電性接合材を介して接合することにより、内部に収容する半導体素子３が外部電気回路に電気的に接続されることとなる。
【００１７】
このような配線導体５は、タングステンやモリブデン・銅・銀等の金属粉末メタライズから成り、タングステン等の金属粉末に適当な有機バインダ・溶剤・可塑剤・分散剤等を添加混合して得たメタライズペーストを従来周知のスクリーン印刷法を採用して絶縁基体１用のセラミックグリーンシートに所定のパターンに印刷塗布し、これを絶縁基体１用の生セラミック成形体とともに焼成することによって絶縁基体１の内部および表面に所定のパターンに形成される。なお、配線導体５の露出表面には、配線導体５が酸化腐食するのを防止するとともに配線導体５と半田等の導電性接合材との接合を良好なものとするために、通常であれば、厚みが１〜１０μｍ程度のニッケルめっき層と厚みが０．１〜３μｍ程度の金めっき層とが順次被着されている。
【００１８】
また、絶縁基体１の上面外周部には高さが０．０１〜５ｍｍ程度の枠状の突起部１ｃが設けられており、それにより上面中央部に底面が略平坦な凹部１ｄが形成されている。この凹部１ｄは、後述するように、絶縁板２との間に密閉空間を形成するためのものであり、この凹部１ｄの底面には静電容量形成用の第一電極７が被着されている。
【００１９】
この第一電極７は、後述する第二電極９とともに感圧素子用の静電容量を形成するためのものであり、絶縁基体１の上面の密閉空間内に露出する領域の全面に被着形成されている。そして、この第一電極７には配線導体５の一つ５ａが接続されており、それによりこの配線導体５ａに半導体素子３の電極を半田バンプ６等の導電性接合材を介して接続すると半導体素子３の電極と第一電極７とが電気的に接続されるようになっている。
【００２０】
このような第一電極７は、タングステンやモリブデン・銅・銀等の金属粉末メタライズから成り、タングステン等の金属粉末に適当な有機バインダ・溶剤・可塑剤・分散剤を添加混合して得たメタライズペーストを従来周知のスクリーン印刷法を採用して絶縁基体１用のセラミックグリーンシートに印刷塗布し、これを絶縁基体１用の生セラミック成形体とともに焼成することによって絶縁基体１の凹部１ｄ底面の全面に形成される。なお、第一電極７の露出表面には、第一電極７が酸化腐食するのを防止するために、通常であれば、厚みが１〜１０μｍ程度のニッケルめっき層が被着されている。
【００２１】
また、絶縁基体１の突起部１ｃの上面にはその全周にわたり枠状の第一接合用メタライズ層８が被着されており、この第一接合用メタライズ層８には、下面の中心部に第二電極９および下面の外周部に第二電極９と電気的に接続された第二接合用メタライズ層１０を有する絶縁板２が、この第二接合用メタライズ層１０とを銀−銅ろう材等の導電性接合材を介して接合することにより取着されている。
【００２２】
この第一接合用メタライズ層８には配線導体５の一つ５ｂが接続されており、それによりこの配線導体５ｂに半導体素子３の電極を半田バンプ６等の導電性接合材を介して電気的に接続すると第一接合用メタライズ層８に接続された第二接合用メタライズ層１０および第二接合用メタライズ層１０に接続された第二電極９と半導体素子３の電極とが電気的に接続されるようになっている。
【００２３】
第一接合用メタライズ層８は、タングステンやモリブデン・銅・銀等の金属粉末メタライズから成り、タングステン等の金属粉末に適当な有機バインダ・溶剤・可塑剤・分散剤を添加混合して得たメタライズペーストを従来周知のスクリーン印刷法を採用して絶縁基体１用のセラミックグリーンシートに印刷塗布し、これを絶縁基体１用の生セラミック成形体とともに焼成することによって絶縁基体１の突起部１ｃ上面に枠状の所定のパターンに形成される。なお、第一接合用メタライズ層８の露出表面には、第一接合用メタライズ層８が酸化腐食するのを防止するとともに第一接合用メタライズ層８と導電性接合材との接合を強固なものとするために、通常であれば、厚みが１〜１０μｍ程度のニッケルめっき層が被着されている。
【００２４】
また、絶縁基体１の上面に取着された絶縁板２は、酸化アルミニウム質焼結体や窒化アルミニウム質焼結体・ムライト質焼結体・窒化珪素質焼結体・炭化珪素質焼結体・ガラス−セラミックス等の電気絶縁材料から成る厚みが０．０１〜５ｍｍの略平板であり、外部の圧力に応じて絶縁基体１側に撓むいわゆる圧力検出用のダイアフラムとして機能する。
【００２５】
なお、絶縁板２は、その厚みが０．０１ｍｍ未満では、その機械的強度が小さいものとなってしまうため、これに大きな外部圧力が印加された場合に破壊されてしまう危険性が大きなものとなり、他方、５ｍｍを超えると、小さな圧力では撓みにくくなり、圧力検出用のダイアフラムとしては不適となってしまう。したがって、絶縁板２の厚みは０．０１〜５ｍｍの範囲が好ましい。
【００２６】
このような絶縁板２は、例えば酸化アルミニウム質焼結体から成る場合であれば、酸化アルミニウム・酸化珪素・酸化マグネシウム・酸化カルシウム等のセラミック原料粉末に適当な有機バインダ・溶剤・可塑剤・分散剤を添加混合して泥漿状となすとともにこれを従来周知のドクタブレード法を採用してシート状に成形することによりセラミックグリーンシートを得、しかる後、このセラミックグリーンシートに適当な打ち抜き加工や切断加工を施すことにより絶縁板２用の生セラミック成形体を得るとともにこの生セラミック成形体を約１６００℃の温度で焼成することにより製作される。
【００２７】
また、絶縁板２の下面には静電容量形成用の第二電極９と、第二接合用メタライズ層１０が被着されている。この第二電極９は、前述の第一電極７とともに感圧素子用の静電容量を形成するための電極として機能し、第二接合用メタライズ層１０は絶縁板２を絶縁基体１に接合するための接合用下地金属層として機能する。
【００２８】
このような第二電極９は、タングステンやモリブデン・銅・銀等の金属粉末メタライズから成り、タングステン等の金属粉末に適当な有機バインダ・溶剤・可塑剤・分散剤を添加混合して得たメタライズペーストを従来周知のスクリーン印刷法を採用して絶縁板２用のセラミックグリーンシートに印刷塗布し、これを絶縁板２用の生セラミック成形体とともに焼成することによって絶縁板２の下面の密閉空間内に露出する領域の中心部に略円形の形状に形成される。なお、第二電極９の露出表面には、第二電極９が酸化腐食するのを防止するとともに第二電極９と導電性接合材との接合を良好とするために、通常であれば、厚みが１〜１０μｍ程度のニッケルめっき層が被着されている。
【００２９】
また、第二接合用メタライズ層１０は、タングステンやモリブデン・銅・銀等の金属粉末メタライズから成り、タングステン等の金属粉末に適当な有機バインダ・溶剤・可塑剤・分散剤を添加混合して得たメタライズペーストを従来周知のスクリーン印刷法を採用して絶縁板２用のセラミックグリーンシートに印刷塗布し、これを絶縁板２用の生セラミック成形体とともに焼成することによって、絶縁板２の外周部に所定のパターンに形成される。なお、第二接合用メタライズ層１０の露出表面には、第二接合用メタライズ層１０が酸化腐食するのを防止するとともに第二接合用メタライズ層１０と導電性接合材との接合を強固なものとするために、通常であれば、厚みが１〜１０μｍ程度のニッケルめっき層が被着されている。
【００３０】
なお、第二電極９と第二接合用メタライズ層１０とは、電気的に接続されており、第一接合用メタライズ層８と第二接合用メタライズ層１０とが銀−銅ろう材等の導電性接合材を介して接合され、それにより、絶縁基体１上面と絶縁板２下面との間に密閉空間が形成されるとともに第一接合用メタライズ層８と第二電極９とが電気的に接続される。
【００３１】
このとき、第一電極７と第二電極９とは、絶縁基体１と絶縁板２との間に形成された空間を挟んで対向しており、これらの間には、第一電極７や第二電極９の面積および第一電極７と第二電極９との間隔に応じて所定の静電容量が形成される。そして、絶縁板２の上面に外部の圧力が印加されると、その圧力に応じて絶縁板２が絶縁基体１側に撓んで第一電極７と第二電極９との間隔が変わり、それにより第一電極７と第二電極９との間の静電容量が変化するので、外部の圧力の変化を静電容量の変化として感知する感圧素子として機能する。そして、この静電容量の変化を凹部１ａ内に収容した半導体素子３に配線導体５ａ・５ｂを介して伝達し、これを半導体素子３で演算処理することによって外部の圧力の大きさを知ることができる。
【００３２】
そして、本発明においては、第一電極７は図２（ａ）に平面図で示すように、絶縁基体１の他方の主面、すなわち上面の密閉空間内に露出する領域の全面に被着形成されており、また、第二電極は図２（ｂ）に平面図で示すように、絶縁基板２の内側主面、すなわち下面の密閉空間内に露出する領域の中心部に、その領域の直径に対して５０〜８０％の直径を有する略円形の形状に被着形成されており、そのことが重要である。
【００３３】
このように第一電極７が絶縁基体１の他方の主面の密閉空間内に露出する領域の略全面に被着形成され、第二電極９が絶縁板２の内側主面の密閉空間内に露出する領域の中心部に、その領域の直径に対して５０〜８０％の直径を有する略円形の形状に被着形成されていることから、第二電極９はパッケージに圧力が印加された場合に、絶縁板２の変位が大きな中心部領域にのみ配設されることとなり、第一電極７と第二電極９の外周部に第一電極７と第二電極９の重なりから成る圧力検出部はなく、そのため第一電極７と第二電極９の外周部に静電容量の変化にあまり寄与しない余計な静電容量が形成されることはないとともに、外部の圧力を感度良く検出することができる。したがって、本発明の圧力検出装置用パッケージによれば、第一電極７と第二電極９との間に形成される静電容量の変化率が高い、小型・高感度で外部の圧力を正確に検出することができる圧力検出装置とすることができる。
【００３４】
なお、第二電極９の直径が絶縁板２の内側主面が密閉空間内に露出する領域の直径の５０％未満であると、第一電極７と第二電極９との間に形成される静電容量が小さいものとなってしまい圧力を良好に検出することが困難となり、他方、８０％を超えると、第一電極７と第二電極９との間に静電容量の変化に寄与しない余計な静電容量が形成されてしまい静電容量の変化率が低下するので圧力検出感度が低くなってしまう。したがって、第二電極９の直径は絶縁板２の内側主面が密閉空間内に露出する領域の直径の５０〜８０％の範囲に特定される。
【００３５】
このように、本発明の圧力検出装置用パッケージによれば、一方の主面に半導体素子３が搭載される絶縁基体１の他方の主面に静電容量形成用の第一電極７を設けるとともに、この第一電極７に対向する静電容量形成用の第二電極９を内側面に有する絶縁板２を絶縁基体１との間に密閉空間を形成するように可撓な状態で絶縁基体１に接合させたことから、半導体素子３を収容する容器と感圧素子とが一体となり、その結果、圧力検出装置を小型化することができる。また、静電容量形成用の第一電極７および第二電極９を、絶縁基体１に設けた配線導体５ａ・５ｂを介して半導体素子３に接続することから、第一電極７および第二電極９を短い距離で半導体素子３に接続することができ、その結果、これらの配線導体５ａ・５ｂ間に発生する不要な静電容量を小さなものとして感度の高い圧力検出装置を提供することができる。
【００３６】
かくして、上述の圧力検出装置用パッケージによれば、搭載部１ｂに半導体素子３を搭載するとともに半導体素子３の各電極と配線導体５とを電気的に接続し、しかる後、半導体素子３を封止することによって小型でかつ感度の高く、外部の圧力を正確に検出することが可能な圧力検出装置となる。
【００３７】
【実施例】
本発明の圧力検出装置用パッケージの実施例を以下に説明する。図２（ｂ）の平面図で示すような、密閉空間内に露出する領域の直径に対して３０〜１００％の範囲内で異なる直径の第二電極９が形成された絶縁板２を作成し、図２（ａ）に平面図で示すような、密閉空間内に露出する領域の全面に第一電極７が形成された絶縁基板１を前述の絶縁板２毎に作成しそれぞれ接合した８種類の評価用試料を作成した。
【００３８】
また、絶縁基体１および絶縁板２の密閉空間内に露出する領域の直径は７．０ｍｍとし、絶縁基体１および絶縁板２を第一電極７と第二電極９との距離が５０μｍとなるように銀−銅ろう材にて接合させた。
【００３９】
そして、各８種類の試料において、絶縁板１の上面に１気圧（１０１ｋＰａ）および１８００ｋＰａの圧力を印加して、その圧力毎に各試料における第一電極７と第二電極９との間の静電容量を測定し、その測定値より各試料の１８００ｋＰａ印加された時の静電容量の変化量を求めた。結果を表１に示す。
【００４０】
【表１】

【００４１】
表１より、静電容量の変化量は、第二電極が密閉空間内に露出する領域の直径対して８０％を超えると変化量が減少することが判った。また、５０％未満では変化量の値が３．０ｐＦより小さくなっており、圧力変化に対する静電容量の検出が困難となることが判った。この評価結果より、密閉空間の領域の直径に対して第二電極９の直径を５０〜８０％とするのが好ましいことがわかった。
【００４２】
なお、本発明は、上述の実施の形態の一例に限定されるものではなく、本発明の要旨を逸脱しない範囲であれば種々の変更は可能である。例えば上述の実施の形態の一例では、絶縁基体１と絶縁板２とをろう付けにより接合したが、絶縁基体１と絶縁板２とは焼結一体化させることにより接合してもよい。
【００４３】
【発明の効果】
以上、説明したように、本発明の圧力検出装置用パッケージによれば、一方の主面に半導体素子が搭載される絶縁基体の他方の主面に静電容量形成用の第一電極を設けるとともに、この第一電極と対向する静電容量形成用の第二電極を有する絶縁板を絶縁基体の他方の主面との間に密閉空間を形成するように可撓な状態で接合したことから、半導体素子を収容する容器と感圧素子とが一体となり、その結果、圧力検出装置を小型化することができるとともに圧力検出用の電極と半導体素子とを接続する配線の短いものとして、これらの配線間に発生する不要な静電容量を小さいものとすることができる。さらに、第一電極が絶縁基体の他方の主面が密閉空間内に露出する領域の全面に被着形成され、第二電極が絶縁板の内側主面が密閉空間内に露出する領域の中心部に、その領域の直径に対して５０〜８０％の直径を有する略円形の形状に被着形成されていることから、第一電極と第二電極の外周部に第一電極と第二電極の重なりから成る圧力検出部はなく、そのため第一電極と第二電極の外周部に静電容量の変化にあまり寄与しない余計な静電容量が形成されることはなく、かつ第二電極は絶縁板の中央部に形成されており絶縁板の中央部は大きく変位するので、外部の圧力を感度良く検出することができる。したがって第一電極と第二電極との間に形成される静電容量の変化率が高いものとなり、その結果、外部の圧力を正確かつ感度よく検出することが可能な圧力検出装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の圧力検出装置用パッケージの実施の形態の一例を示す断面図である。
【図２】（ａ）・（ｂ）はそれぞれ図１に示す圧力検出装置用パッケージの第一電極および第二電極を示す平面図である。
【図３】従来の圧力検出装置用パッケージの断面図である。
【図４】従来の圧力検出装置用パッケージの断面図である。
【符号の説明】
１・・・・・・・・・・・絶縁基体
２・・・・・・・・・・・絶縁板
３・・・・・・・・・・・半導体素子
５、５ａ、５ｂ・・・・・配線導体
７・・・・・・・・・・・第一電極
９・・・・・・・・・・・第二電極[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pressure detection device package used for a pressure detection device for detecting pressure.
[0002]
[Prior art]
Conventionally, a capacitance-type pressure detection device has been known as a pressure detection device for detecting pressure. As shown in a sectional view of FIG. 4, the capacitance type pressure detecting device is housed in a capacitance type pressure sensing element 22 and a package 28 on a wiring board 21 made of a ceramic material or a resin material. (See Patent Document 1).
[0003]
The pressure-sensitive element 22 is made of, for example, an electrically insulating material such as a ceramic material. The insulating base 24 has a concave portion in the center of the upper surface on which one electrode 23 for forming a capacitance is attached. An insulating plate 26, which is joined in a flexible state on the upper surface of the insulating substrate 24 so as to form a closed space between the insulating substrate 24 and the other electrode 25 for forming a capacitance on the lower surface, An external lead terminal 27 for electrically connecting the capacitance forming electrodes 23 and 25 to the outside is provided. Each of the capacitance forming electrodes 23 and 25 is formed by bending the insulating plate 26 in response to an external pressure. The capacitance formed between the electrodes 23 and 25 changes. An external pressure can be detected by subjecting this change in capacitance to arithmetic processing by the arithmetic semiconductor element 29.
[0004]
However, according to this conventional pressure detecting device, since the pressure-sensitive element 22 and the semiconductor element 29 are individually mounted on the wiring board 21, the pressure detecting device becomes large and the pressure detecting electrodes 23 The wiring between the semiconductor element 25 and the semiconductor element 29 is long, and an unnecessary capacitance is formed between the long wirings, so that the sensitivity is low.
[0005]
Therefore, as shown in FIG. 3 of Patent Document 1, an insulating base 11 having a mounting portion 11b on one main surface on which a semiconductor element 13 is mounted, and a semiconductor provided on the surface and inside of the insulating base 11, A plurality of wiring conductors 15 to which respective electrodes of the element 13 are electrically connected; and a plurality of electrostatic conductors attached to the center of the other main surface of the insulating base 11 and electrically connected to one of the wiring conductors 15. A first electrode 17 for forming a capacitance, an insulating plate 12 joined to the other main surface of the insulating base 11 in a flexible state so as to form a sealed space between the other main surface and a central portion of the main surface, A second electrode 19 for forming a capacitance is provided on the inner main surface of the insulating plate 12 so as to face the first electrode 17 and is electrically connected to another one of the wiring conductors 15. A package for pressure sensing device was proposed. According to the pressure detecting package, the first electrode 17 for forming a capacitance is provided on the other main surface of the insulating base 11 having the mounting portion 11b on which the semiconductor element 13 is mounted on one main surface. The insulating plate 12 having a second electrode 19 for forming a capacitance on the inner surface facing the one electrode 17 is formed in a flexible state by forming a closed space between the insulating plate 15 and the other main surface of the insulating base 15. As a result, the pressure sensing element is integrally formed in the package accommodating the semiconductor element 13, and as a result, the pressure detection device can be downsized and the pressure detection electrode and the semiconductor element 13 are connected. By reducing the length of the wiring, unnecessary capacitance generated between these wirings can be reduced.
[0006]
According to the pressure detection device package of Patent Document 1, the first electrode 17 and the second electrode 19 have the other main surface of the insulating base 11 and the inner main surface of the insulating plate 12 exposed in the closed space. It was formed over substantially the entire area.
[0007]
[Patent Document 1]
JP 2001-356064 A (page 2, FIG. 3, FIG. 4)
[0008]
[Problems to be solved by the invention]
However, according to the pressure detecting device package of Patent Document 1, the first electrode 17 and the second electrode 19 are exposed in the closed space, respectively, with the other main surface of the insulating base 11 and the inner main surface of the insulating plate 12. The capacitance is formed between the first electrode 17 and the second electrode 19 because it is formed over substantially the entire surface of the region, and when pressure is applied to this package, the insulating plate 12 Although the central portion of the region corresponding to the closed space is largely displaced, the displacement of the outer peripheral portion is extremely small, so that the outer peripheral portions of the first electrode 17 and the second electrode 19 do not contribute much to the change in capacitance. Rather, the rate of change in the capacitance between the first electrode 17 and the second electrode 19 is small, and the sensitivity of pressure detection is reduced.
[0009]
The present invention has been devised in view of the above-described problems, and an object of the present invention is to provide a pressure detection device that is small, has high sensitivity, and can accurately detect an external pressure. .
[0010]
[Means for Solving the Problems]
A package for a pressure detection device according to the present invention is provided with an insulating base having a mounting portion on which a semiconductor element is mounted on one main surface, and disposed on the surface and inside of the insulating base, and each electrode of the semiconductor element is electrically connected. A plurality of wiring conductors connected to, an insulating plate joined to the insulating base in a flexible state so as to form a substantially disk-shaped closed space between the other main surface of the insulating base, A first electrode for forming a capacitance, which is attached to the other main surface of the insulating base in the closed space and is electrically connected to one of the wiring conductors; and an inner main surface of the insulating plate. A pressure detection device package comprising: a second electrode for forming a capacitance, which is attached so as to face the first electrode, and is electrically connected to another one of the wiring conductors. , The first electrode covers the entire area where the other main surface is exposed in the closed space. The second electrode has a substantially circular shape having a diameter of 50 to 80% of the diameter of the region where the inner main surface is exposed in the closed space. Characterized by being formed on the substrate.
[0011]
According to the pressure sensing device package of the present invention, the first electrode is formed on the entire surface of the region where the other main surface of the insulating base is exposed in the closed space, and the second electrode is formed on the inner main surface of the insulating plate. The first electrode and the second electrode are formed in the central portion of the region where the surface is exposed in the closed space in a substantially circular shape having a diameter of 50 to 80% of the diameter of the region. There is no pressure detecting portion consisting of the overlap of the first electrode and the second electrode on the outer periphery of the first electrode and the second electrode. No pressure is formed, and the second electrode is formed at the center of the insulating plate, and the center of the insulating plate is greatly displaced, so that a pressure detecting device capable of detecting an external pressure with high sensitivity. Package.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the pressure detecting device package of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an example of an embodiment of a package for a pressure detecting device according to the present invention. In the drawing, reference numeral 1 denotes an insulating base, 2 denotes an insulating plate, and 3 denotes a semiconductor element.
[0013]
The insulating substrate 1 is made of a laminate made of an electrically insulating material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon carbide sintered body, a silicon nitride sintered body, and a glass-ceramic. If it is made of aluminum oxide sintered body, for example, an appropriate organic binder, solvent, plasticizer, and dispersant are added to ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. Then, a plurality of ceramic green sheets are obtained by forming into a sheet shape by employing a conventionally known doctor blade method, and thereafter, a suitable punching process and lamination are performed on these ceramic green sheets. By processing and cutting, a green ceramic molded body for the insulating substrate 1 is obtained, and this green ceramic molded body is It is manufactured by firing at a temperature of 600 ° C..
[0014]
The insulating substrate 1 has a concave portion 1a for accommodating the semiconductor element 3 in the center of the lower surface thereof, and thereby functions as a container for accommodating the semiconductor element 3. The center of the bottom surface of the concave portion 1a is a mounting portion 1b on which the semiconductor element 3 is mounted. The semiconductor element 3 is mounted on the mounting portion 1b, and a resin sealing such as an epoxy resin is formed in the concave portion 1a. The semiconductor element 3 is sealed by filling the material 4. In this example, the semiconductor element 3 is sealed by filling a resin sealing material 4 into the recess 1a. However, the semiconductor element 3 is provided with a lid made of metal or ceramic on the lower surface of the insulating base 1 in the recess 1a. May be sealed by joining them so as to close them.
[0015]
A plurality of wiring conductors 5 connected to the respective electrodes of the semiconductor element 3 are led out from the mounting portion 1b. The wiring conductor 5 and the respective electrodes of the semiconductor element 3 are made of a conductive material such as a solder bump 6. By joining via a conductive joining member, each electrode of the semiconductor element 3 and each wiring conductor 5 are electrically connected, and the semiconductor element 3 is fixed to the mounting portion 1b. In this example, the electrodes of the semiconductor element 3 and the wiring conductors 5 are connected via the solder bumps 6, but the electrodes of the semiconductor element 3 and the wiring conductors 5 are connected to another type of electrical connection such as a bonding wire. They may be connected by means.
[0016]
The wiring conductor 5 functions as a conductive path for electrically connecting each electrode of the semiconductor element 3 to an external electric circuit and a first electrode 7 and a second electrode 9 which will be described later. It is led out to the lower surface, and another part is electrically connected to the first electrode 7 and the second electrode 9. The electrodes of the semiconductor element 3 are electrically connected to the wiring conductors 5 via the conductive bonding material 6 and the semiconductor element 3 is sealed with the resin sealing material 4. The semiconductor element 3 housed inside is electrically connected to the external electric circuit by joining the portion led out to the lower surface of the outer periphery of the base 1 to the wiring conductor of the external electric circuit board via a conductive bonding material such as solder. It will be.
[0017]
Such a wiring conductor 5 is made of metal powder of metal such as tungsten, molybdenum, copper, silver or the like, and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer, dispersant, etc. to metal powder of tungsten or the like. The paste is printed and applied in a predetermined pattern on a ceramic green sheet for the insulating substrate 1 by employing a conventionally known screen printing method, and is baked together with the green ceramic molded body for the insulating substrate 1 to thereby form the inside of the insulating substrate 1. And a predetermined pattern on the surface. In addition, on the exposed surface of the wiring conductor 5, in order to prevent the wiring conductor 5 from being oxidized and corroded and to make the connection between the wiring conductor 5 and a conductive bonding material such as solder good, A nickel plating layer having a thickness of about 1 to 10 μm and a gold plating layer having a thickness of about 0.1 to 3 μm are sequentially applied.
[0018]
A frame-shaped projection 1c having a height of about 0.01 to 5 mm is provided on the outer peripheral portion of the upper surface of the insulating base 1, thereby forming a concave portion 1d having a substantially flat bottom surface at the center of the upper surface. I have. The concave portion 1d is for forming a closed space between the concave portion 1d and the insulating plate 2, and a first electrode 7 for forming a capacitance is attached to the bottom surface of the concave portion 1d. I have.
[0019]
This first electrode 7 is for forming a capacitance for a pressure-sensitive element together with a second electrode 9 to be described later, and is formed on the entire surface of the upper surface of the insulating substrate 1 which is exposed in the closed space. Have been. One of the wiring conductors 5a is connected to the first electrode 7 so that when the electrode of the semiconductor element 3 is connected to the wiring conductor 5a via a conductive bonding material such as a solder bump 6, a semiconductor is formed. The electrode of the element 3 and the first electrode 7 are electrically connected.
[0020]
Such a first electrode 7 is made of metallized metal powder such as tungsten, molybdenum, copper, silver, etc., and is obtained by adding and mixing an appropriate organic binder, solvent, plasticizer and dispersant to metal powder such as tungsten. The paste is printed and applied on a ceramic green sheet for the insulating substrate 1 by using a conventionally known screen printing method, and is fired together with the green ceramic molded body for the insulating substrate 1 to thereby obtain the entire bottom surface of the concave portion 1d of the insulating substrate 1. Formed. In addition, a nickel plating layer having a thickness of about 1 to 10 μm is usually applied to the exposed surface of the first electrode 7 in order to prevent the first electrode 7 from being oxidized and corroded.
[0021]
A frame-shaped first bonding metallization layer 8 is attached to the entire upper surface of the protrusion 1c of the insulating base 1 over the entire periphery thereof. The insulating plate 2 having the second electrode 9 and the second metallization layer 10 for electrical connection with the second electrode 9 on the outer peripheral portion of the lower surface is formed by combining the second metallization layer 10 with the silver-copper brazing material. It is attached by bonding via a conductive bonding material such as.
[0022]
One of the wiring conductors 5b is connected to the first bonding metallization layer 8, so that the electrodes of the semiconductor element 3 are electrically connected to the wiring conductor 5b via a conductive bonding material such as a solder bump 6. Is connected, the second metallization layer 10 connected to the first metallization layer 8 and the second electrode 9 connected to the second metallization layer 10 are electrically connected to the electrode of the semiconductor element 3. It has become so.
[0023]
The first bonding metallization layer 8 is made of a metal powder such as tungsten, molybdenum, copper, or silver, and is obtained by adding a suitable organic binder, solvent, plasticizer, and dispersant to a metal powder such as tungsten. The paste is printed and applied on a ceramic green sheet for the insulating substrate 1 by employing a conventionally known screen printing method, and is baked together with the green ceramic molded body for the insulating substrate 1 so that the paste is formed on the upper surface of the protrusion 1c of the insulating substrate 1. It is formed in a predetermined frame-like pattern. The exposed surface of the first bonding metallization layer 8 is provided with a material that prevents the first bonding metallization layer 8 from being oxidized and corroded and that firmly bonds the first bonding metallization layer 8 to the conductive bonding material. Usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied.
[0024]
The insulating plate 2 attached to the upper surface of the insulating base 1 is made of an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, a silicon nitride sintered body, or a silicon carbide sintered body. A substantially flat plate made of an electrically insulating material such as glass-ceramics and having a thickness of 0.01 to 5 mm, and functions as a so-called pressure detecting diaphragm that bends toward the insulating base 1 according to external pressure.
[0025]
If the thickness of the insulating plate 2 is less than 0.01 mm, the mechanical strength of the insulating plate 2 is small. Therefore, there is a great risk that the insulating plate 2 will be broken when a large external pressure is applied thereto. On the other hand, if it exceeds 5 mm, it becomes difficult to bend under a small pressure, and it becomes unsuitable as a diaphragm for pressure detection. Therefore, the thickness of the insulating plate 2 is preferably in the range of 0.01 to 5 mm.
[0026]
If such an insulating plate 2 is made of, for example, a sintered body of aluminum oxide, an organic binder, a solvent, a plasticizer, and a dispersion suitable for ceramic raw material powder such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. A ceramic green sheet is obtained by adding and mixing an agent to form a slurry and forming this into a sheet by employing a conventionally known doctor blade method. Thereafter, the ceramic green sheet is appropriately punched or cut. The green ceramic molded body for the insulating plate 2 is obtained by performing the processing, and the green ceramic molded body is manufactured by firing at a temperature of about 1600 ° C.
[0027]
On the lower surface of the insulating plate 2, a second electrode 9 for forming a capacitance and a second metallized layer 10 for bonding are adhered. The second electrode 9 functions as an electrode for forming a capacitance for a pressure-sensitive element together with the above-described first electrode 7, and the second bonding metallization layer 10 bonds the insulating plate 2 to the insulating base 1. Function as a base metal layer for bonding.
[0028]
Such a second electrode 9 is made of metallized metal powder such as tungsten, molybdenum, copper, silver, etc., and obtained by adding and mixing an appropriate organic binder, solvent, plasticizer and dispersant to metal powder such as tungsten. The paste is printed and applied on a ceramic green sheet for the insulating plate 2 by using a conventionally known screen printing method, and is baked together with the green ceramic molded body for the insulating plate 2 to thereby form the paste in the closed space on the lower surface of the insulating plate 2. A substantially circular shape is formed at the center of the region exposed to the outside. In addition, in order to prevent the second electrode 9 from being oxidized and corroded and to improve the bonding between the second electrode 9 and the conductive bonding material, the exposed surface of the second electrode 9 is usually provided with a thickness. Has a nickel plating layer of about 1 to 10 μm.
[0029]
The second bonding metallization layer 10 is made of metal powder such as tungsten, molybdenum, copper, or silver, and is obtained by adding a suitable organic binder, solvent, plasticizer, and dispersant to metal powder such as tungsten. The metallized paste is applied to a ceramic green sheet for the insulating plate 2 by printing using a conventionally known screen printing method, and is fired together with the green ceramic molded body for the insulating plate 2, thereby forming an outer peripheral portion of the insulating plate 2. Is formed in a predetermined pattern. The exposed surface of the second bonding metallization layer 10 prevents the second bonding metallization layer 10 from being oxidized and corroded, and firmly bonds the second bonding metallization layer 10 to the conductive bonding material. Usually, a nickel plating layer having a thickness of about 1 to 10 μm is applied.
[0030]
The second electrode 9 and the second bonding metallization layer 10 are electrically connected, and the first bonding metallization layer 8 and the second bonding metallization layer 10 are electrically connected to each other by a conductive material such as a silver-copper brazing material. And a closed space is formed between the upper surface of the insulating substrate 1 and the lower surface of the insulating plate 2, and the first metallizing layer 8 and the second electrode 9 are electrically connected to each other. Is done.
[0031]
At this time, the first electrode 7 and the second electrode 9 face each other with a space formed between the insulating base 1 and the insulating plate 2 therebetween. A predetermined capacitance is formed according to the area of the two electrodes 9 and the distance between the first electrode 7 and the second electrode 9. Then, when an external pressure is applied to the upper surface of the insulating plate 2, the insulating plate 2 bends toward the insulating base 1 according to the pressure, and the distance between the first electrode 7 and the second electrode 9 changes. Since the capacitance between the first electrode 7 and the second electrode 9 changes, it functions as a pressure-sensitive element that detects a change in external pressure as a change in capacitance. Then, the change in the capacitance is transmitted to the semiconductor element 3 accommodated in the concave portion 1a via the wiring conductors 5a and 5b, and the magnitude of the external pressure is obtained by performing an arithmetic processing on the semiconductor element 3. Can be.
[0032]
In the present invention, as shown in the plan view of FIG. 2A, the first electrode 7 is formed on the other main surface of the insulating base 1, that is, on the entire surface of the upper surface exposed in the closed space. In addition, as shown in a plan view in FIG. 2B, the second electrode has a diameter on the inner principal surface of the insulating substrate 2, that is, a central portion of a region exposed in the closed space on the lower surface. Is formed in a substantially circular shape having a diameter of 50 to 80% with respect to the above, which is important.
[0033]
As described above, the first electrode 7 is formed on substantially the entire surface of the insulating substrate 1 exposed in the sealed space on the other main surface, and the second electrode 9 is formed in the sealed space on the inner main surface of the insulating plate 2. Since the second electrode 9 is formed in a substantially circular shape having a diameter of 50 to 80% of the diameter of the exposed region at the center of the exposed region, the second electrode 9 is formed when pressure is applied to the package. In addition, the displacement of the insulating plate 2 is disposed only in the central region where the displacement of the insulating plate 2 is large, and the pressure detecting portion formed by the overlap of the first electrode 7 and the second electrode 9 on the outer peripheral portion of the first electrode 7 and the second electrode 9. Therefore, no extra capacitance is formed on the outer peripheral portions of the first electrode 7 and the second electrode 9 which does not contribute much to the change of the capacitance, and the external pressure can be detected with high sensitivity. it can. Therefore, according to the pressure detecting device package of the present invention, the rate of change in the capacitance formed between the first electrode 7 and the second electrode 9 is high, and the external pressure can be accurately detected with small size and high sensitivity. A pressure detecting device capable of detecting the pressure can be provided.
[0034]
If the diameter of the second electrode 9 is less than 50% of the diameter of the region where the inner main surface of the insulating plate 2 is exposed in the closed space, the second electrode 9 is formed between the first electrode 7 and the second electrode 9. The capacitance becomes small and it is difficult to detect the pressure satisfactorily. On the other hand, if it exceeds 80%, it does not contribute to the change in capacitance between the first electrode 7 and the second electrode 9. An unnecessary capacitance is formed and the rate of change of the capacitance is reduced, so that the pressure detection sensitivity is lowered. Therefore, the diameter of the second electrode 9 is specified in the range of 50 to 80% of the diameter of the region where the inner main surface of the insulating plate 2 is exposed in the closed space.
[0035]
As described above, according to the pressure detecting device package of the present invention, the first electrode 7 for forming a capacitance is provided on the other main surface of the insulating base 1 on which the semiconductor element 3 is mounted on one main surface. An insulating plate 2 having a second electrode 9 for forming a capacitance facing the first electrode 7 on an inner surface thereof is formed in a flexible state so as to form a closed space between the insulating plate 2 and the insulating substrate 1. Therefore, the container for accommodating the semiconductor element 3 and the pressure-sensitive element are integrated, and as a result, the pressure detection device can be downsized. Further, since the first electrode 7 and the second electrode 9 for forming the capacitance are connected to the semiconductor element 3 via the wiring conductors 5a and 5b provided on the insulating base 1, the first electrode 7 and the second electrode 9 are connected. 9 can be connected to the semiconductor element 3 at a short distance, and as a result, an unnecessary capacitance generated between these wiring conductors 5a and 5b can be reduced to provide a highly sensitive pressure detecting device. .
[0036]
Thus, according to the above-described package for a pressure detecting device, the semiconductor element 3 is mounted on the mounting portion 1b, and each electrode of the semiconductor element 3 is electrically connected to the wiring conductor 5, and then the semiconductor element 3 is sealed. By stopping, a pressure detection device that is small and has high sensitivity and can accurately detect external pressure is provided.
[0037]
【Example】
An embodiment of the package for a pressure detecting device according to the present invention will be described below. As shown in the plan view of FIG. 2B, the insulating plate 2 on which the second electrodes 9 having different diameters are formed within a range of 30 to 100% with respect to the diameter of the region exposed in the closed space is prepared. As shown in the plan view of FIG. 2A, eight types of insulating substrates 1 in which the first electrode 7 is formed on the entire surface of the region exposed in the enclosed space are formed for each of the above-described insulating plates 2 and bonded respectively. A sample for evaluation was prepared.
[0038]
The diameter of a region of the insulating base 1 and the insulating plate 2 exposed in the closed space is set to 7.0 mm, and the distance between the first electrode 7 and the second electrode 9 is set to 50 μm. Was joined with a silver-copper brazing material.
[0039]
Then, a pressure of 1 atm (101 kPa) and a pressure of 1800 kPa are applied to the upper surface of the insulating plate 1 in each of the eight types of samples, and the static pressure between the first electrode 7 and the second electrode 9 in each sample is applied at each pressure. The capacitance was measured, and the amount of change in capacitance when 1800 kPa was applied to each sample was determined from the measured value. Table 1 shows the results.
[0040]
[Table 1]

[0041]
From Table 1, it was found that the amount of change in capacitance decreases when the second electrode exceeds 80% of the diameter of the region exposed in the closed space. Further, when the value is less than 50%, the value of the amount of change is smaller than 3.0 pF, and it has been found that it is difficult to detect the capacitance with respect to the change in pressure. From this evaluation result, it was found that the diameter of the second electrode 9 was preferably set to 50 to 80% of the diameter of the region of the closed space.
[0042]
Note that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. For example, in the above-described embodiment, the insulating base 1 and the insulating plate 2 are joined by brazing. However, the insulating base 1 and the insulating plate 2 may be joined by sintering and integration.
[0043]
【The invention's effect】
As described above, according to the pressure detecting device package of the present invention, the first electrode for forming a capacitance is provided on the other main surface of the insulating base on which the semiconductor element is mounted on one main surface. Since the first electrode and the insulating plate having the second electrode for forming the capacitance facing the first electrode are joined in a flexible state so as to form a closed space between the other main surface of the insulating base, The container for accommodating the semiconductor element and the pressure-sensitive element are integrated with each other. As a result, the pressure detection device can be downsized, and the wiring for connecting the electrode for pressure detection and the semiconductor element can be shortened. Unnecessary capacitance generated between them can be reduced. Further, the first electrode is formed on the entire surface of the region where the other main surface of the insulating base is exposed in the closed space, and the second electrode is formed at the center of the region where the inner main surface of the insulating plate is exposed in the closed space. Since the first electrode and the second electrode are formed in a substantially circular shape having a diameter of 50 to 80% of the diameter of the region, the first electrode and the second electrode There is no pressure detector consisting of overlaps, so that no extra capacitance is formed on the outer periphery of the first electrode and the second electrode, which does not contribute much to the change in capacitance, and the second electrode is an insulating plate. Since the central portion of the insulating plate is greatly displaced, the external pressure can be detected with high sensitivity. Therefore, the change rate of the capacitance formed between the first electrode and the second electrode is high, and as a result, it is possible to provide a pressure detection device that can accurately and sensitively detect an external pressure. Can be.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of an embodiment of a package for a pressure detecting device according to the present invention.
2 (a) and 2 (b) are plan views showing a first electrode and a second electrode of the pressure detection device package shown in FIG. 1, respectively.
FIG. 3 is a sectional view of a conventional package for a pressure detecting device.
FIG. 4 is a cross-sectional view of a conventional package for a pressure detection device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulating base 2 ... Insulating plate 3 ... Semiconductor elements 5, 5a, 5b ... ..Wiring conductor 7 ... First electrode 9 ... Second electrode

Claims

An insulating base having a mounting portion on which a semiconductor element is mounted on one main surface, a plurality of wiring conductors disposed on the surface and inside of the insulating base, and each electrode of the semiconductor element is electrically connected; An insulating plate joined to the insulating base in a flexible state so as to form a substantially disk-shaped sealed space between the insulating base and the other main surface of the insulating base; A first electrode for forming a capacitance, which is attached to the other main surface and is electrically connected to one of the wiring conductors, and faces the first electrode on an inner main surface of the insulating plate. A pressure detection device package comprising: a second electrode for forming a capacitance, which is attached and electrically connected to another one of the wiring conductors, wherein the first electrode includes the other electrode. The main surface is formed so as to adhere to the entire surface exposed in the closed space, and the second electrode Wherein the inner main surface is formed in a substantially circular shape having a diameter of 50 to 80% of the diameter of the area exposed in the closed space at the center of the area. Package for detector.