JP3764255B2 - Semiconductor light emitting device - Google Patents

Semiconductor light emitting device Download PDF

Info

Publication number
JP3764255B2
JP3764255B2 JP20468297A JP20468297A JP3764255B2 JP 3764255 B2 JP3764255 B2 JP 3764255B2 JP 20468297 A JP20468297 A JP 20468297A JP 20468297 A JP20468297 A JP 20468297A JP 3764255 B2 JP3764255 B2 JP 3764255B2
Authority
JP
Japan
Prior art keywords
light emitting
lead
voltage
chip
emitting element
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP20468297A
Other languages
Japanese (ja)
Other versions
JPH1154799A (en
Inventor
慎二 磯川
秀和 戸田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rohm Co Ltd
Original Assignee
Rohm Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rohm Co Ltd filed Critical Rohm Co Ltd
Priority to JP20468297A priority Critical patent/JP3764255B2/en
Priority to US09/003,145 priority patent/US6054716A/en
Publication of JPH1154799A publication Critical patent/JPH1154799A/en
Application granted granted Critical
Publication of JP3764255B2 publication Critical patent/JP3764255B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
    • H01L2224/45138—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
    • H01L2224/45144—Gold (Au) as principal constituent
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48135—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip
    • H01L2224/48137—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip the bodies being arranged next to each other, e.g. on a common substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48257—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a die pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/13—Discrete devices, e.g. 3 terminal devices
    • H01L2924/1304—Transistor
    • H01L2924/1306—Field-effect transistor [FET]
    • H01L2924/13091—Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Landscapes

  • Led Device Packages (AREA)
  • Led Devices (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は保護素子が設けられている半導体発光素子に関する。さらに詳しくは、交流電圧駆動または静電気などにより発光素子に逆方向電圧や所定の電圧以上の順方向電圧が印加される場合にも発光素子がその静電気などにより破壊しにくいように保護素子が設けられている半導体発光素子に関する。
【０００２】
【従来の技術】
従来、半導体発光素子は、ｐ形層とｎ形層とが直接接合してｐｎ接合を形成するか、その間に活性層を挟持してダブルヘテロ接合を形成して構成され、ｐ形層とｎ形層との間に順方向の電圧が印加されることにより、ｐｎ接合部または活性層で発光する。このような発光素子は、たとえば図６に示されるように、半導体の積層体からなる発光素子チップ（以下、ＬＥＤチップという）３が第１のリード１の先端にボンディングされ、一方の電極が第１のリード１と電気的に接続され、他方の電極が第２のリード２と金線４などにより電気的に接続されてその周囲がＬＥＤチップ３の光に対して透明な樹脂パッケージ６により覆われることにより形成されている。
【０００３】
このような発光素子は、ダイオード構造になっているため、逆方向の電圧が印加されても電流が流れない整流作用を利用して、直流電圧を両電極間に印加しないで交流電圧を印加することにより、交流で順方向電圧になる場合にのみ電流が流れて発光する光を利用する使用方法も採用されている。
【０００４】
【発明が解決しようとする課題】
通常の半導体発光素子は、一般にＧａＡｓ系やＧａＰ系やチッ化ガリウム系などの化合物半導体が用いられているが、これら化合物半導体を用いた場合には逆方向に印加される電圧に対して弱く、半導体層が破壊することがある。とくに、チッ化ガリウム系化合物半導体においては、その逆方向の耐圧が５０Ｖ程度と低く逆方向の印加電圧に対してとくに破壊しやすいこと、またバンドギャップエネルギーが大きいため、ＧａＡｓ系などを用いた発光素子より動作電圧も４Ｖ程度と高くなること、などのため交流電圧の印加で半導体発光素子が破損したり、その特性が劣化するという問題がある。
【０００５】
また、交流電圧を印加する駆動でなくても、外部からサージ電圧などの大きな電圧が印加される場合、チッ化ガリウム系化合物半導体では順方向電圧でも１５０Ｖ程度で破壊されやすいという問題がある。
【０００６】
これらの逆方向電圧や静電気の印加に対する破壊を防止するため、半導体発光素子が組み込まれる回路内で、半導体発光素子と並列で半導体発光素子と逆方向にツェナーダイオードを組み込むことが行われる場合もある。しかし、回路内に組み込まれる前の製造工程や出荷に伴う搬送工程、または回路基板に組み込む際などのハンドリング時に静電気で破壊したり、外部回路でＬＥＤの他にダイオードなどを組み込むスペースや工数を必要とするという問題がある。
【０００７】
本発明はこのような問題を解決するためになされたもので、製造工程や搬送工程、または回路基板への実装時などのハンドリング時に静電気が印加されても、また交流駆動などに伴う逆方向電圧が印加される場合にも、損傷や破壊を生じにくくすると共に、従来の発光素子の性能や製造コストに影響を殆ど及ぼすことがない半導体発光素子を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明による半導体発光素子は、並置して設けられる第１および第２のリードと、該第１および第２のリードの２本の先端部に跨って、上面が１つの楕円形状で湾曲状に形成された凹部と、該凹部内の前記第１のリードにボンディングされる発光素子チップと、該発光素子チップの２つの電極をそれぞれ前記第１および第２のリードと電気的に接続する接続手段と、前記凹部内の第２のリードにボンディングされ、前記第１および第２のリード間に電気的に接続されて前記発光素子チップに印加され得る少なくとも逆方向電圧に対して前記発光素子チップを保護する保護素子とからなっている。
【００１０】
ここに保護素子とは、発光素子チップに印加され得る逆方向電圧を短絡したり、発光素子チップの動作電圧より高い所定の電圧以上の順方向電圧をショートさせ得る素子を意味し、ツェナーダイオードやトランジスタのダイオード接続、ＭＯＳＦＥＴのゲートとソースまたはドレインとを短絡した素子またはこれらの複合素子、ＩＣなどを含む。また、接続手段とは、金線や導電性接着剤などにより接続し得る手段を意味する。
【００１１】
この構造にすることにより、保護素子は発光素子チップと共に同じ湾曲状の凹部内にマウントされるため、ほぼ同じ高さのところで近接しており、発光素子チップと保護素子とのダイボンディングおよびワイヤボンディングを同時に行うことができ、工数増にならない。しかも、同じ凹部ないでワイヤボンディングをすることができるため、ワイヤボンディングが容易になり、また第１および第２のリードに亘って凹部が形成される場合には、凹部の側壁を越えてワイヤボンディングをする必要がなく、ワイヤのタッチ不良などの虞れもない。さらに、広い凹部内で反射した光を全て利用することができるため、発光部には従来と何等の変化をもたらすことなく、容易に保護素子をランプ型の半導体発光素子内に内蔵することができる。
【００１２】
前記第２のリードにマウントされる保護素子は、該保護素子の表面が前記第１のリードにマウントされる発光素子チップの表面より低くなるように設けられていることにより、発光素子チップから横方向に進んだ光を凹部の内壁で上方に反射させることができるため、光の取出し効率が向上して好ましい。
【００１３】
前記発光素子チップがチッ化ガリウム系化合物半導体からなり、前記保護素子がツェナーダイオードであれば、とくに逆電圧に弱く、また順方向でも高電圧の印加に弱いチッ化ガリウム系化合物半導体が用いられる半導体発光素子において、逆方向電圧やサージ電圧などの印加に対して保護されるため好ましい。とくに保護素子としてツェナーダイオードが用いられることにより、発光素子チップに順方向にサージなどの高電圧が印加されてもツェナーダイオードのツェナー特性により、発光素子チップにダメージを与えることなく保護されると共に、通常の動作には何等の異常を来さない。ここにチッ化ガリウム系化合物半導体とは、III 族元素のＧａとＶ族元素のＮとの化合物またはIII 族元素のＧａの一部がＡｌ、Ｉｎなどの他のIII 族元素と置換したものおよび／またはＶ族元素のＮの一部がＰ、Ａｓなどの他のＶ族元素と置換した化合物からなる半導体をいう。
【００１４】
【発明の実施の形態】
つぎに、図面を参照しながら本発明の半導体発光素子について説明をする。
【００１５】
本発明の半導体発光素子は、その一実施形態の平面および断面の説明図が図１に示されるように、第１および第２のリード１、２が並置されており、その第１および第２のリード１、２の先端部に両方のリードに亘って連続する湾曲状の凹部７が形成されている。その凹部７内の第１のリード１にＬＥＤチップ３がボンディングされて、ＬＥＤチップ３の一方の電極、たとえばｎ側電極は第１のリード１と電気的に接続され、他方の電極、たとえばｐ側電極が第２のリード２と金線４などの接続手段によりそれぞれ電気的に接続されている。さらに、凹部７内の第２のリード２に保護素子であるツェナーダイオードチップ５がボンディングされ、第１および第２のリード１、２間にＬＥＤチップ３と逆方向になるように電気的に接続されている。そして、その周囲が樹脂パッケージ６により覆われている。
【００１６】
第１および第２のリード１、２は、鉄材または銅材からなる厚さが０.４〜０.５ｍｍ程度の板状体をパンチングにより打ち抜き、第１および第２のリード１、２の上部から円錐型のポンチなどによりスタンピングすることにより、その先端部に両方のリード１、２に亘って椀型の凹部７が形成されている。このスタンピングの際、両リード１、２の間隙部にジグを挿入しておくことにより、間隙部が押し潰されることなく、外側に広がって両リード１、２に連続した湾曲状の凹部７が形成される。この凹部７は従来第１のリード１のみに形成されていたものを両方のリードに跨がって形成しているため、両方のリード１、２の間隔を広げることなく、すなわち発光素子としての樹脂パッケージ６を大きくすることなく、凹部７を大きく形成することができる。なお、製造段階では第１および第２のリード１、２の下端部はリードフレームの枠部で連結されている。
【００１７】
ＬＥＤチップ３は、たとえば青色系（紫外線から黄色）の発光色を有するチップの一例の断面図が図４に示されるように形成される。すなわち、たとえばサファイア（Ａｌ2 Ｏ3 単結晶）などからなる基板３１の表面に、ＧａＮからなる低温バッファ層３２が０.０１〜０.２μｍ程度、クラッド層となるｎ形層３３が１〜５μｍ程度、ＩｎＧａＮ系（ＩｎとＧａの比率が種々変わり得ることを意味する、以下同じ）化合物半導体からなる活性層３４が０.０５〜０.３μｍ程度、ｐ形のＡｌＧａＮ系（ＡｌとＧａの比率が種々変わり得ることを意味する、以下同じ）化合物半導体層３５ａおよびＧａＮ層３５ｂからなるｐ形層（クラッド層）３５が０.２〜１μｍ程度、それぞれ順次積層されて、その表面に電流拡散層３７を介してｐ側電極３８が形成されている。また、積層された半導体層３３〜３５の一部が除去されて露出したｎ形層３３にｎ側電極３９が設けられることにより形成されている。
【００１８】
ツェナーダイオードチップ５は、通常のシリコン半導体などからなり、不純物濃度の高い半導体のｐｎ接合に大きい逆方向電圧を印加すると電子がトンネル効果によってｐｎ接合を通って流れる現象を利用したものである。この逆方向の電流が流れ始める電圧（ツェナー電圧）はその不純物濃度により設定される。したがって、このツェナー電圧をＬＥＤチップ３の動作電圧より高い所定の電圧に設定しておき、ＬＥＤチップ３とツェナーダイオードチップ５とが並列で逆方向になるように第１および第２のリード１、２に接続することにより、ＬＥＤチップ３の動作に支障を来すことはない。
【００１９】
このＬＥＤチップ３およびツェナーダイオードチップ５が図１に示されるように、凹部７の底部の第１のリード１および第２のリード２にそれぞれ銀ペーストなどの接着剤によりボンディングされ、前述のように、ＬＥＤチップ３のｎ側電極３９とｐ側電極３８（図４参照）が第１のリード１および第２のリード２と、ツェナーダイオードチップ５の正電極が第１のリード１とそれぞれ金線４により連結されて電気的に接続されている。なお、ツェナーダイオードチップ５の負電極は導電性接着剤により直接第２のリード２と電気的に接続されている。ＬＥＤチップ３も上下両面にそれぞれｎ側電極およびｐ側電極が設けられる構造のものであれば、一方の電極はＬＥＤチップが導電性接着剤によりダイボンディングされることにより、ワイヤボンディングの必要なく電気的に接続される。そして、ツェナーダイオードチップ５を含めたこれらの周囲がＬＥＤチップ３により発光する光を透過する透明または乳白色のエポキシ樹脂などによりモールドされることにより、樹脂パッケージ６で被覆された本発明の半導体発光素子が得られる。樹脂パッケージ６は、図１に示されるように、発光面側が凸レンズになるようにドーム形状に形成されることにより、ランプタイプの発光素子が得られる。
【００２０】
この例では、凹部７の底部は第１および第２のリード１、２で同じ高さになっていたが、図２に示されるように、保護素子５が設けられる第２のリード２の底部を低くするか、保護素子５の高さをＬＥＤチップ３の高さより低く形成することにより、ＬＥＤチップ３から横方向に出射した光を凹部７の内壁で効率よく上方に反射させることができるため好ましい。凹部７の底部に段差を設ける場合は、段差の付いたポンチによりスタンピングすることにより簡単に形成することができる。なお、図１と同じ部分には同じ符号を付してある。また、段差を設けるか否かに拘らず、保護素子５の部分に白色塗料などの反射しやすい絶縁物質で被覆したり、椀型形状になるように反射物質を塗布して上方に光を集光しやすいようにすることもできる。
【００２１】
図３は、本発明の半導体発光素子さらに他の実施形態を示す断面説明図である。すなわちこの例では、凹部を第１および第２のリード１、２に亘って設けるのではなく、第１のリード１の先端のみに平面形状が楕円形状で、湾曲状の凹部１１が形成され、その凹部１１内にＬＥＤチップ３およびツェナーダイオードチップ５がマウントされ、それぞれの電極が第１のリード１と第２のリード２に前述と同様の接続関係になるように金線４により電気的に接続されている。この構造でも、同じ凹部内で２つのチップをワイヤボンディングにより接続することができる。
【００２２】
本発明の半導体発光素子によれば、ツェナーダイオードチップが内蔵されて、図５にその等価回路図が示されているように、ＬＥＤチップ３と並列にツェナーダイオードチップ５がその極性がＬＥＤチップ３と逆になるように接続されている。そのため、ＬＥＤチップ３を駆動する電源が交流電源であっても、ＬＥＤチップ３に順方向の電圧になる位相のときは、ツェナーダイオードチップ５には逆方向電圧でツェナー電圧より低い電圧であるため電流は流れず、ＬＥＤチップ３に電流が流れて発光する。また、交流電源がＬＥＤチップ３に逆方向の電圧になる位相のときは、ツェナーダイオードチップ５を介して電流が流れる。そのため、交流電圧がＬＥＤチップ３に対して逆方向の電圧の位相となるときでも、ＬＥＤチップ３には逆方向の電圧は殆ど印加されない。また、静電気が印加される場合、その静電気がＬＥＤチップ３の逆方向であればツェナーダイオードチップ５を介して放電し、ＬＥＤチップ３に順方向である場合はその電圧がツェナー電圧より高ければツェナーダイオードチップ５を介して放電するためＬＥＤチップ３を保護し、ツェナー電圧より低ければＬＥＤチップ３を介して放電するが、その電圧は低い電圧であるためＬＥＤチップ３を損傷することはない。その結果、逆方向の電圧や静電気のサージに対して弱いＬＥＤチップ３であってもＬＥＤチップ３に高い電圧が印加されず、ＬＥＤチップ３を破損したり、劣化させたりすることがない。
【００２３】
一方、本発明の半導体発光素子では、ツェナーダイオードチップ５が第１および第２のリード１、２の先端部の両方に跨がって、または第１のリード１のみに平面形状が楕円形状で大きく形成された凹部７、１１内にＬＥＤチップ３と共にマウントされているため、ＬＥＤチップ３のダイボンディングおよびワイヤボンディングと一緒に、同じ工程で行うことができる。しかも、両方のリードに跨がって凹部７が設けられている場合は、全体を大きくすることなくその凹部７を大きくすることができ、両方のチップおよびワイヤが接触する虞れはなく、余裕をもってダイボンディングおよびワイヤボンディングをすることができる。さらに、両方のリードに亘って凹部が設けられることにより、凹部７の側壁を越えて他のリードとのワイヤボンディングをする必要がないため、一層ワイヤボンディングの信頼性も向上する。またＬＥＤチップ３の横方向から出射する光は凹部の内壁で反射して上方に進み、大きくした凹部全体で発光しているように放射され、明るい発光素子が得られる。その結果、コスト上昇や発光特性の低下をもたらすことなく保護素子を内蔵した半導体発光素子が得られる。
【００２４】
前述の例では、保護素子としてツェナーダイオードチップを用いたが、チップでなくてパッケージングされた製品状のものを使用してもよい。また、ツェナーダイオードでなくても通常のダイオードでも、ＬＥＤチップに対する逆方向の電圧に対して保護することができる。さらに、ダイオードでなくても、トランジスタをダイオード接続したものや、ＭＯＳＦＥＴのゲートとソースまたはドレインとを接続したもの、またはこれらを組み合わせてツェナーダイオードと同様に両方向に保護する複合素子またはＩＣなど、ダイオードと同様にＬＥＤチップを保護することができる素子であればよい。
【００２５】
また、前述の例では、発光素子としてチッ化ガリウム系化合物半導体を用いた青色系の半導体発光素子であったが、チッ化ガリウム系化合物半導体はとくに逆方向の電圧や高電圧により破壊されやすいため効果が大きい。しかし、これに限定されるものではなく、ＧａＡｓ系、ＡｌＧａＡｓ系、ＡｌＧａＩｎＰ系、ＩｎＰ系などの赤色系や緑色系の発光素子についても、保護素子が設けられることにより同様に逆方向電圧や静電気に対して強い半導体発光素子が得られる。
【００２６】
【発明の効果】
本発明によれば、発光素子を構成する２本のリードの端部の両方に跨って、または１本のリードで平面形状が楕円状の凹部が形成され、その凹部内にＬＥＤチップと保護素子とがマウントされているため、製造工数増や、素子サイズの増加を伴うことなく、また発光素子の発光特性に何等の変化を来すことなく保護素子を内蔵した半導体発光素子が得られる。その結果、逆方向電圧の印加や静電気による高電圧の印加に対しても損傷することがなく、信頼性が大幅に向上すると共に、半製品や製品の状態での取扱もアースバンドの使用や静電気除去の特別な注意を払う必要がなくなり、作業効率が大幅に向上する。
【図面の簡単な説明】
【図１】本発明の半導体発光素子の一実施形態の平面および断面の説明図である。
【図２】本発明の半導体発光素子の他の実施形態の断面説明図である。
【図３】本発明の半導体発光素子のさらに他の実施形態の説明図である。
【図４】図１のＬＥＤチップの一例の断面説明図である。
【図５】図１の半導体発光素子の接続関係の等価回路図である。
【図６】従来の半導体発光素子の一例の斜視説明図である。
【符号の説明】
１ 第１のリード
２ 第２のリード
３ ＬＥＤチップ
４ 金線
５ ツェナーダイオードチップ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor light emitting element provided with a protective element. More specifically, a protective element is provided to prevent the light emitting element from being damaged by static electricity even when a reverse voltage or a forward voltage higher than a predetermined voltage is applied to the light emitting element due to AC voltage driving or static electricity. The present invention relates to a semiconductor light emitting device.
[0002]
[Prior art]
Conventionally, a semiconductor light emitting device is configured by forming a pn junction by directly joining a p-type layer and an n-type layer, or by forming a double heterojunction by sandwiching an active layer between the p-type layer and the n-type layer. When a forward voltage is applied to the shape layer, light is emitted from the pn junction or the active layer. For example, as shown in FIG. 6, a light emitting element chip (hereinafter referred to as an LED chip) 3 made of a semiconductor laminate is bonded to the tip of a first lead 1 and one electrode is connected to a first light emitting element. One lead 1 is electrically connected, and the other electrode is electrically connected to the second lead 2 by a gold wire 4 or the like, and its periphery is covered with a resin package 6 that is transparent to the light of the LED chip 3. Is formed.
[0003]
Since such a light emitting element has a diode structure, an AC voltage is applied without applying a DC voltage between both electrodes by using a rectifying action in which no current flows even when a reverse voltage is applied. Accordingly, a method of using light that emits light when a current flows only when a forward voltage is generated by alternating current is also employed.
[0004]
[Problems to be solved by the invention]
In general, compound semiconductors such as GaAs, GaP, and gallium nitride are generally used for semiconductor light emitting devices, but when these compound semiconductors are used, they are weak against a voltage applied in the reverse direction. The semiconductor layer may be destroyed. In particular, gallium nitride-based compound semiconductors have a breakdown voltage in the reverse direction as low as about 50 V, and are particularly susceptible to breakdown with respect to an applied voltage in the reverse direction. Since the operating voltage is about 4V higher than that of the device, there is a problem in that the semiconductor light emitting device is damaged or its characteristics are deteriorated by application of an AC voltage.
[0005]
Further, even when driving is not performed by applying an AC voltage, when a large voltage such as a surge voltage is applied from the outside, there is a problem that a gallium nitride compound semiconductor is easily broken even at a forward voltage of about 150V.
[0006]
In order to prevent breakdown due to application of reverse voltage or static electricity, a Zener diode may be incorporated in the circuit in which the semiconductor light emitting element is incorporated in parallel with the semiconductor light emitting element in the opposite direction to the semiconductor light emitting element. . However, there is a need for space and man-hours to break down by static electricity during handling such as manufacturing process before being built into the circuit, transport process accompanying shipment, or when being built into the circuit board, or to incorporate diodes other than LEDs in the external circuit There is a problem that.
[0007]
The present invention has been made to solve such problems. Even if static electricity is applied during the manufacturing process, the transporting process, or the handling such as mounting on a circuit board, the reverse voltage due to the AC driving or the like is also provided. It is an object of the present invention to provide a semiconductor light emitting device that is less likely to be damaged or destroyed even when a voltage is applied, and that hardly affects the performance and manufacturing cost of a conventional light emitting device.
[0008]
[Means for Solving the Problems]
The semiconductor light emitting device according to the present invention includes first and second lead provided in juxtaposition across two of the distal end portion of the first and second lead, the upper surface in a curved shape at one elliptical A formed recess, a light emitting element chip bonded to the first lead in the recess, and connection means for electrically connecting the two electrodes of the light emitting element chip to the first and second leads, respectively. The light emitting element chip with respect to at least a reverse voltage that can be applied to the light emitting element chip by being bonded to the second lead in the recess and electrically connected between the first and second leads. It consists of protective elements to protect.
[0010]
Here, the protective element means an element that can short-circuit a reverse voltage that can be applied to the light-emitting element chip, or can short-circuit a forward voltage that is higher than a predetermined voltage that is higher than the operating voltage of the light-emitting element chip. It includes a diode connection of a transistor, a device in which a gate and a source or drain of a MOSFET are short-circuited, or a composite device thereof, an IC, or the like. The connecting means means means that can be connected by a gold wire or a conductive adhesive.
[0011]
With this structure, the protective element is mounted in the same curved recess together with the light emitting element chip, so that they are close to each other at almost the same height, and die bonding and wire bonding between the light emitting element chip and the protective element are performed. Can be performed at the same time, and man-hours are not increased. Moreover, since wire bonding can be performed without the same recess, wire bonding is facilitated, and when the recess is formed across the first and second leads, the wire bonding is performed across the side wall of the recess. There is no need for a wire touch failure. Furthermore, since all the light reflected in the wide concave portion can be used, the protective element can be easily incorporated in the lamp-type semiconductor light emitting element without causing any change in the light emitting part. .
[0012]
The protective element mounted on the second lead is provided laterally from the light emitting element chip by providing the surface of the protective element to be lower than the surface of the light emitting element chip mounted on the first lead. Since light that has traveled in the direction can be reflected upward by the inner wall of the recess, the light extraction efficiency is improved, which is preferable.
[0013]
If the light-emitting element chip is made of a gallium nitride compound semiconductor and the protection element is a Zener diode, a semiconductor that uses a gallium nitride compound semiconductor that is particularly weak against reverse voltage and weak against high voltage application in the forward direction. In a light emitting element, it is preferable because it is protected against application of reverse voltage or surge voltage. In particular, by using a Zener diode as a protective element, even if a high voltage such as a surge is applied to the light emitting element chip in the forward direction, the Zener diode is protected without damaging the light emitting element chip, There is no abnormality in normal operation. Here, the gallium nitride compound semiconductor is a compound in which a group III element Ga and a group V element N or a part of the group III element Ga is substituted with another group III element such as Al or In, and A semiconductor composed of a compound in which a part of N of the group V element is substituted with another group V element such as P or As.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, the semiconductor light emitting device of the present invention will be described with reference to the drawings.
[0015]
The semiconductor light emitting device of the present invention has first and second leads 1 and 2 juxtaposed, as shown in FIG. A curved concave portion 7 is formed at the tip of each of the leads 1 and 2 so as to extend over both leads. The LED chip 3 is bonded to the first lead 1 in the recess 7, and one electrode, for example, the n-side electrode of the LED chip 3 is electrically connected to the first lead 1, and the other electrode, for example, p The side electrodes are electrically connected to each other by connecting means such as the second lead 2 and the gold wire 4. Further, a Zener diode chip 5 as a protection element is bonded to the second lead 2 in the recess 7 and is electrically connected between the first and second leads 1 and 2 so as to be opposite to the LED chip 3. Has been. And the periphery is covered with the resin package 6.
[0016]
The first and second leads 1 and 2 are punched by punching a plate made of iron or copper and having a thickness of about 0.4 to 0.5 mm, and the upper portions of the first and second leads 1 and 2 By stamping with a conical punch or the like, a saddle-shaped concave portion 7 is formed at the tip portion over both leads 1 and 2. At the time of this stamping, by inserting a jig into the gap between the leads 1 and 2, the gap is not crushed, and the curved concave portion 7 extending outward and continuing to the leads 1 and 2 is formed. It is formed. Since the concave portion 7 is formed only on the first lead 1 so as to straddle both leads, the gap between both the leads 1 and 2 is not increased, that is, as a light emitting element. Without increasing the size of the resin package 6, the recess 7 can be formed larger. In the manufacturing stage, the lower ends of the first and second leads 1 and 2 are connected by a frame portion of the lead frame.
[0017]
The LED chip 3 is formed, for example, as shown in FIG. 4 in a cross-sectional view of a chip having a blue-based (ultraviolet to yellow) emission color. That is, for example, on the surface of the substrate 31 made of sapphire (Al 2 O 3 single crystal) or the like, the low-temperature buffer layer 32 made of GaN is about 0.01 to 0.2 μm, and the n-type layer 33 that becomes the cladding layer is 1 to 5 μm. The active layer 34 made of an InGaN-based compound semiconductor (meaning that the ratio of In and Ga can be changed variously, the same applies hereinafter) compound semiconductor is about 0.05 to 0.3 μm, p-type AlGaN-based (ratio of Al to Ga) P-type layer (cladding layer) 35 composed of a compound semiconductor layer 35a and a GaN layer 35b is sequentially stacked in a thickness of about 0.2 to 1 μm, and a current diffusion layer is formed on the surface thereof. A p-side electrode 38 is formed via 37. Further, the n-side electrode 39 is provided on the n-type layer 33 exposed by removing a part of the stacked semiconductor layers 33 to 35.
[0018]
The Zener diode chip 5 is made of a normal silicon semiconductor or the like, and utilizes a phenomenon in which electrons flow through the pn junction by a tunnel effect when a large reverse voltage is applied to a pn junction of a semiconductor having a high impurity concentration. The voltage at which the reverse current starts to flow (zener voltage) is set by the impurity concentration. Therefore, the Zener voltage is set to a predetermined voltage higher than the operating voltage of the LED chip 3, and the first and second leads 1, so that the LED chip 3 and the Zener diode chip 5 are in parallel and in opposite directions. By connecting to 2, the operation of the LED chip 3 is not hindered.
[0019]
As shown in FIG. 1, the LED chip 3 and the Zener diode chip 5 are bonded to the first lead 1 and the second lead 2 at the bottom of the recess 7 with an adhesive such as silver paste, respectively, as described above. The n-side electrode 39 and the p-side electrode 38 (see FIG. 4) of the LED chip 3 are the first lead 1 and the second lead 2, and the positive electrode of the Zener diode chip 5 is the first lead 1 and the gold wire, respectively. 4 are connected and electrically connected. The negative electrode of the Zener diode chip 5 is directly electrically connected to the second lead 2 by a conductive adhesive. If the LED chip 3 also has a structure in which an n-side electrode and a p-side electrode are provided on both upper and lower surfaces, one electrode can be electrically connected without the need for wire bonding by die bonding the LED chip with a conductive adhesive. Connected. Then, the semiconductor light emitting device of the present invention covered with the resin package 6 is formed by molding the periphery including the Zener diode chip 5 with a transparent or milky white epoxy resin that transmits light emitted from the LED chip 3. Is obtained. As shown in FIG. 1, the resin package 6 is formed in a dome shape so that the light emitting surface side is a convex lens, whereby a lamp-type light emitting element is obtained.
[0020]
In this example, the bottom of the recess 7 has the same height as the first and second leads 1 and 2, but as shown in FIG. 2, the bottom of the second lead 2 provided with the protection element 5. Or by forming the height of the protective element 5 lower than the height of the LED chip 3, the light emitted from the LED chip 3 in the lateral direction can be efficiently reflected upward by the inner wall of the recess 7. preferable. When a step is provided at the bottom of the recess 7, it can be easily formed by stamping with a punch having a step. In addition, the same code | symbol is attached | subjected to the same part as FIG. Regardless of whether or not there is a step, the protective element 5 is covered with a reflective material such as white paint that is easy to reflect, or a reflective material is applied so as to form a saddle shape to collect light upward. It can also make it easy to shine.
[0021]
FIG. 3 is a cross-sectional explanatory view showing still another embodiment of the semiconductor light emitting device of the present invention. That is, in this example, the concave portion is not provided over the first and second leads 1 and 2, but the planar shape is an elliptical shape and the curved concave portion 11 is formed only at the tip of the first lead 1. The LED chip 3 and the Zener diode chip 5 are mounted in the recess 11 and are electrically connected by the gold wire 4 so that the respective electrodes are connected to the first lead 1 and the second lead 2 in the same manner as described above. It is connected. Even in this structure, two chips can be connected by wire bonding in the same recess.
[0022]
According to the semiconductor light emitting device of the present invention, a Zener diode chip is built in, and as shown in an equivalent circuit diagram in FIG. 5, the Zener diode chip 5 has a polarity in parallel with the LED chip 3. And are connected so as to be reversed. Therefore, even if the power source for driving the LED chip 3 is an AC power source, the Zener diode chip 5 has a reverse voltage lower than the Zener voltage when the LED chip 3 has a phase that becomes a forward voltage. No current flows, and current flows through the LED chip 3 to emit light. Further, when the AC power supply has a phase in which the reverse voltage is applied to the LED chip 3, a current flows through the Zener diode chip 5. Therefore, even when the AC voltage is in the reverse voltage phase with respect to the LED chip 3, the reverse voltage is hardly applied to the LED chip 3. In addition, when static electricity is applied, if the static electricity is in the reverse direction of the LED chip 3, it is discharged through the Zener diode chip 5, and in the forward direction to the LED chip 3, if the voltage is higher than the Zener voltage, the Zener is discharged. The LED chip 3 is protected to discharge through the diode chip 5, and if it is lower than the Zener voltage, it is discharged through the LED chip 3. However, since the voltage is low, the LED chip 3 is not damaged. As a result, even if the LED chip 3 is weak against reverse voltage or electrostatic surge, a high voltage is not applied to the LED chip 3, and the LED chip 3 is not damaged or deteriorated.
[0023]
On the other hand, in the semiconductor light emitting device of the present invention, the Zener diode chip 5 extends over both the front ends of the first and second leads 1 and 2 or only the first lead 1 has an elliptical planar shape. Since it is mounted together with the LED chip 3 in the recesses 7 and 11 formed to be large, it can be performed in the same process together with die bonding and wire bonding of the LED chip 3. In addition, when the concave portion 7 is provided across both leads, the concave portion 7 can be enlarged without enlarging the whole, and there is no possibility that both chips and wires come into contact with each other. Die bonding and wire bonding can be performed. Furthermore, since the recesses are provided over both leads, it is not necessary to perform wire bonding with other leads beyond the side wall of the recess 7, so that the reliability of wire bonding is further improved. Further, the light emitted from the lateral direction of the LED chip 3 is reflected by the inner wall of the recess and travels upward, and is emitted as if it is emitted from the entire enlarged recess, thereby obtaining a bright light emitting element. As a result, a semiconductor light-emitting element incorporating a protective element can be obtained without increasing costs or reducing light emission characteristics.
[0024]
In the above example, a Zener diode chip is used as the protective element, but a packaged product may be used instead of the chip. Moreover, even if it is not a Zener diode but a normal diode, it can protect with respect to the voltage of the reverse direction with respect to a LED chip. Furthermore, even if it is not a diode, a diode such as a diode-connected transistor, a MOSFET gate connected to a source or drain, or a composite element or IC that combines these to protect in both directions like a Zener diode Any element can be used as long as it can protect the LED chip.
[0025]
In the above example, a blue semiconductor light emitting device using a gallium nitride compound semiconductor as the light emitting device is used. However, a gallium nitride compound semiconductor is particularly susceptible to destruction by a reverse voltage or a high voltage. Great effect. However, the present invention is not limited to this, and red and green light emitting elements such as GaAs, AlGaAs, AlGaInP, and InP are also protected against reverse voltage and static electricity by providing protective elements. In contrast, a strong semiconductor light emitting device can be obtained.
[0026]
【The invention's effect】
According to the present invention, a concave portion having an elliptical planar shape is formed over both ends of two leads constituting the light emitting element, or the lead shape is formed in the concave portion. Thus, a semiconductor light emitting device having a built-in protective element can be obtained without increasing the number of manufacturing steps, increasing the device size, and causing no change in the light emission characteristics of the light emitting device. As a result, there is no damage even when reverse voltage is applied or high voltage is applied due to static electricity, and reliability is greatly improved. There is no need to pay special attention to removal, and work efficiency is greatly improved.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a plane and a cross section of an embodiment of a semiconductor light emitting device of the present invention.
FIG. 2 is a cross-sectional explanatory view of another embodiment of a semiconductor light emitting device of the present invention.
FIG. 3 is an explanatory view of still another embodiment of the semiconductor light emitting device of the present invention.
4 is a cross-sectional explanatory diagram of an example of the LED chip of FIG. 1;
5 is an equivalent circuit diagram of a connection relationship of the semiconductor light emitting device of FIG. 1. FIG.
FIG. 6 is an explanatory perspective view of an example of a conventional semiconductor light emitting device.
[Explanation of symbols]
1 1st lead 2 2nd lead 3 LED chip 4 Gold wire 5 Zener diode chip

Claims (2)

並置して設けられる第１および第２のリードと、該第１および第２のリードの２本の先端部に跨って、上面が１つの楕円形状で湾曲状に形成された凹部と、該凹部内の前記第１のリードにマウントされる発光素子チップと、該発光素子チップの２つの電極をそれぞれ前記第１および第２のリードと電気的に接続する接続手段と、前記凹部内の第２のリードにマウントされ、前記第１および第２のリード間に電気的に接続されて前記発光素子チップに印加され得る少なくとも逆方向電圧に対して前記発光素子チップを保護する保護素子とからなる半導体発光素子。A first lead and a second lead provided in parallel; a concave portion whose upper surface is formed in a curved shape with an elliptical shape across the two tip portions of the first and second leads ; and the concave portion A light-emitting element chip mounted on the first lead, a connection means for electrically connecting two electrodes of the light-emitting element chip to the first and second leads, respectively, and a second in the recess And a protection element that is mounted on the lead and is electrically connected between the first and second leads and protects the light-emitting element chip against at least a reverse voltage that can be applied to the light-emitting element chip. Light emitting element. 前記第２のリードにマウントされる保護素子は、該保護素子の表面が前記第１のリードにマウントされる発光素子チップの表面より低くなるように設けられてなる請求項１記載の半導体発光素子。The second protection element is mounted on the lead, the semiconductor light emitting element of the surface of the protective element is provided so as to be lower than the surface of the light emitting device chip which is mounted on the first lead according to claim 1, wherein .
JP20468297A 1997-01-10 1997-07-30 Semiconductor light emitting device Expired - Lifetime JP3764255B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP20468297A JP3764255B2 (en) 1997-07-30 1997-07-30 Semiconductor light emitting device
US09/003,145 US6054716A (en) 1997-01-10 1998-01-06 Semiconductor light emitting device having a protecting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP20468297A JP3764255B2 (en) 1997-07-30 1997-07-30 Semiconductor light emitting device

Publications (2)

Publication Number Publication Date
JPH1154799A JPH1154799A (en) 1999-02-26
JP3764255B2 true JP3764255B2 (en) 2006-04-05

Family

ID=16494567

Family Applications (1)

Application Number Title Priority Date Filing Date
JP20468297A Expired - Lifetime JP3764255B2 (en) 1997-01-10 1997-07-30 Semiconductor light emitting device

Country Status (1)

Country Link
JP (1) JP3764255B2 (en)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5914501A (en) * 1998-08-27 1999-06-22 Hewlett-Packard Company Light emitting diode assembly having integrated electrostatic discharge protection
JP4611721B2 (en) * 2004-11-25 2011-01-12 株式会社小糸製作所 Light emitting device and vehicle lamp
JP4836230B2 (en) * 2005-06-17 2011-12-14 株式会社小糸製作所 Light emitting device and light source device using the same
KR100643471B1 (en) 2005-11-24 2006-11-10 엘지전자 주식회사 Light emitting diode pakage and fabricating method thereof
KR100775574B1 (en) 2006-04-20 2007-11-15 알티전자 주식회사 LED package with high efficiency
JP4882634B2 (en) * 2006-09-26 2012-02-22 日亜化学工業株式会社 Light emitting device
JP5045166B2 (en) * 2007-03-16 2012-10-10 ソニー株式会社 Light source device and liquid crystal display device
JP5196107B2 (en) * 2007-03-29 2013-05-15 日亜化学工業株式会社 Light emitting device
JP5060172B2 (en) * 2007-05-29 2012-10-31 岩谷産業株式会社 Semiconductor light emitting device
JP5275642B2 (en) * 2008-02-12 2013-08-28 スタンレー電気株式会社 Light emitting device and manufacturing method thereof

Also Published As

Publication number Publication date
JPH1154799A (en) 1999-02-26

Similar Documents

Publication Publication Date Title
JP3673621B2 (en) Chip light emitting device
JP3686569B2 (en) Semiconductor light emitting device and display device using the same
JP3559435B2 (en) Semiconductor light emitting device
US7683396B2 (en) High power light emitting device assembly utilizing ESD protective means sandwiched between dual sub-mounts
KR100686416B1 (en) Composite light-emitting device, semiconductor light-emitting unit and method for fabricating the unit
EP1601019B1 (en) Light emitting diode chip with monolithically integrated diode for electrostatic discharge protection and method of forming the same
US20060267040A1 (en) High-brightness LED with protective function of electrostatic discharge damage
US20060163604A1 (en) Gallium nitride-based light emitting device having light emitting diode for protecting electrostatic discharge, and melthod for manufacturing the same
KR102120268B1 (en) Light­emitting device
JP2002314138A (en) Light emitting device
KR20080085343A (en) Light emitting diode
JPH10200159A (en) Semiconductor light emitting element
JP3663281B2 (en) Semiconductor light emitting device
JP3764255B2 (en) Semiconductor light emitting device
JP2000124506A (en) Semiconductor light-emitting element
JP3348843B2 (en) Light emitting diode and dot matrix display using the same
JP3911839B2 (en) Semiconductor light emitting device
EP1403933B1 (en) Semiconductor light emitting diode
JP2001036140A (en) Static countermeasure devised surface-mounting led
JP3787220B2 (en) Chip light emitting device
JP3723328B2 (en) Semiconductor light emitting device
JPH11103096A (en) Semiconductor light-emitting device
KR102131853B1 (en) Light emitting diode array
US20150076444A1 (en) Semiconductor light emitting element and light emitting device including the same
JP2002335012A (en) Light emitting diode and dot matrix display using the same

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20041222

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20050913

A521 Request for written amendment filed

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20051114

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20060110

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20060119

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20090127

Year of fee payment: 3

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120127

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120127

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130127

Year of fee payment: 7

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130127

Year of fee payment: 7

EXPY Cancellation because of completion of term