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JP3751731B2 - Manufacturing method of semiconductor device - Google Patents

Manufacturing method of semiconductor device Download PDF

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Publication number
JP3751731B2
JP3751731B2 JP35061097A JP35061097A JP3751731B2 JP 3751731 B2 JP3751731 B2 JP 3751731B2 JP 35061097 A JP35061097 A JP 35061097A JP 35061097 A JP35061097 A JP 35061097A JP 3751731 B2 JP3751731 B2 JP 3751731B2
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film
semiconductor device
material film
photomask
region
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JP35061097A
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JPH11186319A (en
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衛吾 白樫
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Panasonic Corp
Panasonic Holdings Corp
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Panasonic Corp
Matsushita Electric Industrial Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
    • H01L24/01—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
    • H01L24/02—Bonding areas ; Manufacturing methods related thereto
    • H01L24/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L24/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
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    • H01L24/00—Arrangements for connecting or disconnecting semiconductor or solid-state bodies; Methods or apparatus related thereto
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    • H01L24/02—Bonding areas ; Manufacturing methods related thereto
    • H01L24/03—Manufacturing methods
    • H—ELECTRICITY
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    • H01L2224/02—Bonding areas; Manufacturing methods related thereto
    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/04042—Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
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    • H01L2224/04—Structure, shape, material or disposition of the bonding areas prior to the connecting process
    • H01L2224/05—Structure, shape, material or disposition of the bonding areas prior to the connecting process of an individual bonding area
    • H01L2224/0554—External layer
    • H01L2224/0555—Shape
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    • 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
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    • 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
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    • 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
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    • 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
    • H01L2224/484—Connecting portions
    • H01L2224/48463—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
    • H01L2224/48465—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond the other connecting portion not on the bonding area being a wedge bond, i.e. ball-to-wedge, regular stitch
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    • H01L2224/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
    • H01L2224/852—Applying energy for connecting
    • H01L2224/85201—Compression bonding
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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Wire Bonding (AREA)

Description

【０００１】
【産業上の利用分野】
本発明は、半導体装置の製造方法に関するものである。
【０００２】
【従来の技術】
近年、半導体部品は高集積化、高密度化の傾向にあり、それに伴い半導体装置に搭載する半導体チップは、微細化、大型化している。一方、半導体チップケースであるパッケージは安価な樹脂封止型の物が多用されている。しかしながら、半導体チップの微細化、大型化に伴って、半導体チップは封止樹脂からの応力を強く受けるようになり、例えば封止樹脂中のシリカ充填剤によって半導体チップの表面保護膜（例えばＳｉＯ2、Ｓｉ3Ｎ4）にクラックが発生したり、さらには配線の断線、特性変動を引き起こし、半導体チップが不良になるという事故がしばしば報告されるようになっている。
【０００３】
そこで多くの半導体メーカーではチップ表面に外部からの衝撃を緩衝する外部衝撃緩衝膜としてポリイミド膜等の硬化樹脂膜を形成して、前記不都合を解消する試みがなされている。図５には、ポリイミド膜の形成方法の従来例が、また、図６には、ポリイミド膜を外部衝撃緩衝膜として用いた半導体チップを搭載した半導体装置の従来構造が示されている。
【０００４】
図５(Ａ)〜(Ｄ)は外部衝撃緩衝膜の形成プロセスの要部断面を拡大して示した図であり、２１は半導体ウェーハ、２２はボンディングパッド、２３は塗布ノズル、２４は感光性ポリイミド材料膜、２５はフォトマスク、２６は紫外線、２７は感光する領域、２８は現像液ノズル、２９は現像液、３０は開口部、３１はスクライブライン、３２は表面保護膜、３３はポリイミド膜からなる外部衝撃緩衝膜である。
【０００５】
まず、図５（Ａ）に示すように、所定の工程が終了した半導体ウェーハ２１を回転させ、表面保護膜３２及びボンディングパッド２２上に塗布ノズル２３によって感光性ポリイミド材料を滴下する。そして、そのまま半導体ウェーハ２１を一定時間回転させ半導体ウェーハ２１上面一面に感光性ポリイミド材料を拡げて、感光性ポイイミド材料膜２４を形成する。
【０００６】
次に、図５(Ｂ)に示すように、露光装置とフォトマスク２５を用いてボンディングパッド２２の周囲に開口部３０を設けるために、感光性ポリイミド材料膜２４を除去する部分に露光装置で紫外線２６を照射し、感光させる。
【０００７】
次に、図５(Ｃ)に示すように、半導体ウェーハ２１上の感光性ポリイミド材料膜２４に現像液ノズル２８で現像液２９を塗布、もしくは吹き付けて、感光した領域２７を除去し、開口部３０を設ける。
【０００８】
次に、図５（Ｄ）に示すように、高温で感光性ポリイミド材料膜２４を硬化して外部衝撃緩衝膜３３を形成し、スクライブライン３１を切断機で切断し半導体チップを形成する。
【０００９】
また、図６は半導体装置の要部断面図を拡大して示した図であり、図において、３４はボンディングボール、３５はボンディングワイヤー、３６はインナーリード、３７はアウターリード、３８は封止樹脂、３９はポリイミド膜のクラック部分、４０は界面剥離部分である。
【００１０】
この半導体装置では、インナーリード３６と直接導通しているアウターリード３７が半導体装置の外部にあることにより、半導体チップ２１の内部から電気信号及び外部基板（図示せず）からの電気信号が入出力されるようになっている。かかる半導体装置の製造方法を簡単に説明すると、前記したように形成した半導体チップ２１のボンディングパッド２２とインナーリード３６とを電気的に導通させるためにワイヤーボンダーによってボンディングワイヤー３５の先端を電気スパーク等によって溶融させてボンディングボール３４を形成する。そして、形成したたボンディングボール３４をボンディングパッド２２に熱、超音波、荷重を用いて接着する。このようにしてボンディングパッド２２とボンディングワイヤー３５の一端を接続し、ボンディングワイヤー３５の他端をインナーリード３６に接続し、しかる後、このようにしてワイヤーボンディングがなされた半導体チップ２２を封止樹脂３８で封止することで、半導体装置が完成する。
【００１１】
【発明が解決しようとする課題】
しかしながら上記従来の構成では、半導体装置の製造工程におけるワイヤーボンディング工程時、ワイヤーボンダーの設備の精度が十分でない場合や、設備異常、オペレーターの操作及び設定ミス等によってボンディングボール３４の接着位置がボンディングパッド２２の中心から著しくずれる場合がある。この場合、外部衝撃緩衝膜３３の開口部３０の端部とボンディングボール３４が接触して、かかる端部にクラック３９が発生し、半導体チップ２１と外部衝撃緩衝膜３３の間に界面剥離が発生する。この界面剥離が発生するとその剥離部分４０に水分が侵入し、半導体チップ２１が耐湿性不良を起こし、半導体装置の信頼性が著しく低下してしまうという欠点がある。
【００１２】
上記課題について鑑み、本発明の目的はボンディングボールが著しくボンディングパッドの中心からずれた場合でも、接触によるポリイミド膜のクラックを発生させることのない半導体装置を製造する方法を提供するものである。
【００１３】
【課題を解決するための手段】
上記課題を解決するために、本発明では、次のような構成を備えている。
【００１５】
請求項１の半導体装置の製造方法では、ボンディングパッドを有する半導体ウェーハ上に外部衝撃緩衝膜を形成し、この外部衝撃緩衝膜に前記ボンディングパットに達する開口を形成してなる半導体装置の製造方法において、半導体ウェーハ上に、前記外部衝撃緩衝膜となる感光性材料膜を形成する感光性材料膜形成工程と、前記開口に対応して前記感光性材料膜上に設定した第一の領域を表面から膜厚方向中途部まで選択的に感光させる第一の感光工程と、前記第一の領域内に含まれ、かつ前記第一の領域より小さく設定した前記感光性材料膜上の第二の領域を、前記ボンディングパットに達するまで選択的に感光させる第二の感光工程と、第一，第二の領域が感光した感光性材料膜を現像する現像工程とを含み、前記第一の感光工程に用いるフォトマスクとして、前記第二の感光工程に用いるフォトマスクを用い、かつ、第一の感光工程では、フォトマスクと半導体ウェーハとの間の離間間隔が第二の感光工程でのフォトマスクと半導体ウェーハとの離間間隔とは異なるように、フォトマスクを配置することに特徴を有しており、これにより、感光される第一，第二の領域の大きさの違いにより、形成される外部衝撃緩衝膜の開口上端縁部には切欠部が形成される、という作用を有する。また、第一，第二の感光工程で、一つのフォトマスクを兼用することができ、その分、半導体装置の製造に要するコストを低減することができるうえ、フォトマスクの交換に要する時間も必要なくなる、という作用を有する。
【００１６】
請求項２では、請求項１記載の半導体装置の製造方法において、前記第一の感光工程と前記第二の感光工程とを、逆の順序で行うことに特徴を有しており、これにより、請求項１と同様、形成される外部衝撃緩衝膜の開口上端縁部には切欠部が形成されることになる、という作用を有する。
【００１８】
請求項３では、請求項１または２のいずれか記載の半導体装置の製造方法において、感光性材料膜として、ポジ型感光材料膜を半導体ウェーハ上に形成することに特徴としており、これにより、開口を容易にかつ精度よく形成することができる、という作用を有する。
【００１９】
請求項４では、請求項１ないし３のいずれか記載の半導体装置の製造方法において、感光性材料膜として、ポリイミド膜を半導体ウェーハ上に形成することに特徴を有しており、これにより、十分な衝撃緩衝性能を備えた外部衝撃緩衝膜を形成することができる、という作用を有する。
【００２０】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を参照しながら説明する。
【００２１】
第一の実施の形態
図１（Ａ）〜（Ｄ）は、本発明の第一の実施の形態の半導体装置の製造方法における工程順断面図を示す。また、図２に一般的なポジティブ型感光性ポリイミド材料の露光量と残膜率の関係を示す図を示す。本実施の形態では、図２に示す特性を有するポジティブ型感光性ポリイミド材料から外部衝撃緩衝膜を形成している。また、図３には本実施の形態で得ることができる外部衝撃緩衝膜を形成した半導体装置の一例を示した。
【００２２】
図１（Ａ）〜（Ｅ）において、１は半導体チップ、２はボンディングパッド、３は表面保護膜、４はポジティブ型感光性ポリイミド材料膜、５は塗布ノズル、６は第一のフォトマスク、７は紫外線、８は第一の領域、９は第二のフォトマスク、１０は第二の領域、１１は現像ノズル、１２は現像液、１３は開口部、１４はボンディングボール、１５はボンディングワイヤー、１６はインナーリード、１７はアウターリード、１８は封止樹脂、１９はポリイミド膜からなる外部衝撃緩衝膜である。
【００２３】
感光性材料膜形成工程
まず、図１（Ａ）に示すように、所定の工程が終了し、ボンディングパッド２及びボンディングパッド２の部分を開口した表面保護膜３を有する半導体ウェーハ１に塗布ノズル５でポジティブ型感光性ポリイミド材料を上方より滴下し、半導体ウェーハ１を回転させながら全面に広げて、ポジティブ型感光性ポリイミド材料膜４を形成する。この時の半導体ウェーハ１の回転数によってポジティブ型感光性ポリイミド材料膜４の膜厚が決定する。回転数とポジティブ型感光性ポリイミド材料膜４の膜厚との関係は、ポリイミド材料の粘度等によって変化するが、本実施の形態では、回転数を調整することで、ポジティブ型感光性ポリイミド材料膜４の膜厚が１５μｍ程度となるように、ポジティブ型感光性ポリイミド材料を塗布する。
【００２４】
第一の感光工程
次に、図１（Ｂ）に示すように、ステッパーもしくはアライナーで第一のフォトマスク６を用いて紫外線７でポジティブ型感光性ポリイミド材料膜４を感光させる。この工程で用いる第一のフォトマスク６の開口はボンディングパッド２もしくは表面保護膜３の開口部を大きく包括する平面的な大きさ（以下、単に大きさという）に、すなわち、ボンディングパッド２もしくは表面保護膜３の開口部より一回り大きく形成されている。そして、このような開口を有する第一のフォトマスク６を、照射する紫外線７の焦点位置にくるように、かつ、開口がボンディングパット２の上方位置にくるように配置する。
【００２５】
そして、このような形状を有する第一のフォトマスク６を介してポジティブ型感光性ポリイミド材料膜４上の第一の領域８を感光する。感光した第一の領域８は、第一のフォトマスク６の開口と同等の形、すなわち、ボンディングパッド２もしくは表面保護膜３の開口部を大きく包括する形、すなわち、ボンディングパッド２や表面保護膜３の開口部より一回り大きく形成される。具体的には、本実施の形態では、感光する第一の領域８は、ボンディングパッド２より周囲５μｍ程度大きく形成される。しかしながら、ボンディングパッド２が他のボンディングパッド２と近接して在る場合には、第一の領域８の大きさは若干小さくする必要がある。要は、第一の領域８の大きさを次の工程で感光する第二の領域１０より大きくすれば問題とはならない。
【００２６】
また、第一の領域８を形成するための紫外線７の露光量は、図２に示す１００ｍｊ／ｃｍ2の露光量が適当である。すなわち、現段階では現像を行わないが、後の工程で説明する現像工程・キュア工程を実施すると、当初の膜厚１５μｍに対して７．５μｍ程度の膜厚になる、つまり、５０％のポジティブ型感光性ポリイミ材料膜４がボンディングパッド２の近傍に残膜する程度の露光量が適当である。
【００２７】
ここでは１００ｍｊ／ｃｍ2で第一の領域８の感光を実施したが、紫外線７の露光量によってポジティブ型感光性ポリイミド材料膜４の残膜をコントロール出来ることは図２から容易に推測できる。
【００２８】
第二の感光工程
次に、図１（Ｃ）に示すように、第二のフォトマスク９を用いてボンディングパッド２もしくは表面保護膜３の開口部に合わせて第二の領域１０を感光する。この工程で用いる第二のフォトマスク９の開口はボンディングパッド２もしくは表面保護膜３の開口部と同じ大きさに形成されている。そして、このような開口を有する第二のフォトマスク９を、照射する紫外線７の焦点位置で、かつ開口がボンディングパッド２の上方位置にくるように配置する。
【００２９】
本実施の形態では、表面保護膜３の開口部に合わせて第二の領域１０を形成するが、後の工程において行うワイヤーボンディング工程（本実施の形態の説明では詳細な説明を省略している）での作業マージンを考慮して第二の領域１０の大きさを決定する必要がある。すなわち、第二の領域１０は第一の領域８より小さい大きさであれば本発明の目的を果たすことが出来る。
【００３０】
また、第二の領域１０を形成するための紫外線７の露光量は図２に示す４００ｍｊ／ｃｍ2以上、すなわち、残膜が０％となる露光量が適当である。具体的には、本実施の形態では、このときの紫外線の露光量は５００ｍｊ／ｃｍ2 としている。これら図１（Ｂ）、図１（Ｃ）で説明した紫外線７の露光量はポジティブ型感光性ポリイミド材料膜４の特性によって変更されるものであるのはいうまでもない。
【００３１】
現像工程
次に、図１（Ｄ）に示すように、半導体ウェーハ１を回転させながら現像液ノズル１１から現像液１２をスプレーし、感光した第一の領域部８、および第二の領域１０を除去することによって図１（Ｄ）に示されるような段差状の切欠部１３ａのあるポジティブ型感光性ポリイミド材料膜４の開口部１３を形成する。本実施の形態では、スプレー形式の現像方法を行ったが、現像液１２を半導体ウェーハ１上に多量滴下し、溶解する方法等、現像の目的を果たすものであれば方法は問わない。
【００３２】
キュア工程
次に、図１（Ｅ）に示すように、硬化炉やオーブンを用いて半導体ウェーハ１を２００〜４００℃の温度でキュアし、ポジティブ型感光性ポリイミド材料膜４を硬化することで、ポリイミド膜からなる外部衝撃緩衝膜１９を得る。また、ポジティブ型感光性ポリイミド材料膜４はキュアを行うと硬化収縮するため、本実施の形態の説明で用いたポリイミド材料の場合、第一の領域８の周縁下方に位置するポリイミド膜１９の膜厚は５μｍ程度となった。また、その他の膜厚は１０μｍ程度に仕上がった。したがって、図１（Ａ）で説明した半導体ウェーハ１上に形成するポジティブ型感光性ポリイミド材料膜４の膜厚はキュア時の硬化収縮率（外部衝撃緩衝膜１９の膜厚／ポジティブ型感光性ポリイミド材料膜４の膜厚）とワイヤーボンディング工程での作業マージンを考慮して決定する。
【００３３】
このような開口部１３に切欠部１３ａがある外部衝撃緩衝膜１９を有する半導体装置の一例を図３に示す。この例ではボンディングパッド２は１００μｍ□でワイヤーボンディング後のボンディングボール１４の図の左右方向断面直径は約９０μｍ、厚みは約２０μｍであるため、ボンディングボール１４がボンディングパッド２の中心から５μｍ以上ずれた場合、従来の形状では開口部１３の端部とボンディングボール１４の端部が接触していたが、本発明のように、ボンディングパッド２の周囲に幅５μｍ、膜厚５μｍの切欠部１３ａを設ければ、開口部１３の端部とボンディングボール１４の端部とは接触せず、したがって、ボンディングパッド２の中心に対するボンディングボール１４のずれのマージンを３〜５μｍ大きく設定することが可能となることがわかる。
【００３４】
第二の実施の形態
以下、本発明の第二の実施の形態について、図面を参照しながら説明する。
【００３５】
図４は、本実施の形態の半導体装置の製造方法における工程順の断面図を示している。
【００３６】
図４（Ａ）〜（Ｅ）において、１は半導体チップ、２はボンディングパッド、３は表面保護膜、４はポジティブ型感光性ポリイミド材料膜、５は塗布ノズル、７は紫外線、８は第一の領域、１０は第二の領域、１１は現像ノズル、１２は現像液、１３は開口部、１９はポリイミド膜、２０はフォトマスクである。
【００３７】
感光性材料膜形成工程
まず、図４（Ａ）に示すように、所定の工程が終了し、ボンディングパッド２及びボンディングパッド２の部分を開口した表面保護膜３を有する半導体ウェーハ１に塗布ノズル５でポジティブ型感光性ポリイミド材料を上方より滴下し、半導体ウェーハ１を回転させながら全面に広げて、ポジティブ型感光性ポリイミド材料膜４を形成する。この時の半導体ウェーハ１の回転数によってポジティブ型感光性ポリイミド材料膜４の膜厚が決定する。回転数とポジティブ型感光性ポリイミド材料膜４の膜厚との関係はポジティブ型感光性ポリイミド材料の粘度等によって変化するが、本実施の形態では、回転数を調整することで、ポジティブ型感光性材料膜４の膜厚が１５μｍ程度となるように、ポジティブ型感光性ポリイミド材料を塗布した。
【００３８】
第一の感光工程
次に、図４（Ｂ）に示すように、ステッパーもしくはアライナーでフォトマスク２０を用いて紫外線７でポジティブ型感光性ポリイミド材料膜４を感光させる。この工程で用いるフォトマスク２０の開口はボンディングパッド２もしくは表面保護膜３の開口部とほぼ同一の大きさに形成されている。そして、このような開口を有するフォトマスク２０を、ボンディングパッド２もしくは表面保護膜３の開口部の上方位置にくるように配置する。さらには、この工程ではフォトマスク２０を半導体ウェーハ１から通常の紫外線７の焦点距離よりも大きくずらす、すなわち、フォトマスク２０と半導体ウェーハ１との離間間隔を通常の紫外線７の焦点距離の場合より開けた状態で、ポジティブ型感光性ポリイミド材料膜４を感光させる。
【００３９】
具体的には、本実施の形態では、フォトマスク２０の配置位置を通常の紫外線７の焦点位置よりも１５μｍだけポジティブ型感光性ポリイミド材料膜４の表面より離間した位置に配置した状態で、ポジティブ型感光性ポリイミド材料膜４上の第一の領域８の感光する。このような状態で感光を行うと、フォトマスク２０での紫外線７の漏れが発生し、遮光が不完全となり、フォトマスク２０の通常の焦点位置での感光領域より大きい領域を感光することができる。
【００４０】
したがって、この工程により、フォトマスク２０を介して感光されるポジティブ型感光性ポリイミド材料膜４上の第一の領域８は、フォトマスク２０の開口よりやや大きい形、すなわち、ボンディングパッド２もしくは表面保護膜３の開口部を大きく包括する形に、つまり、ボンディングパッド２もしくは保護膜３の開口部より一回り大きくなる。具体的には、本実施の形態では、感光される第一の領域８は、ボンディングパッド２の周囲５μｍ程度大きく形成される。しかしながら、ボンディングパッド２が他のボンディングパッド２と近接して在る場合には、第一の領域８の大きさは小さくする必要がある。第一の領域８の大きさは次の工程で感光する第二の領域１０より大きければ問題とはならない。
【００４１】
また、第一の領域８を感光するための紫外線７の露光量は、図２に示す１００ｍｊ／ｃｍ2の露光量が適当である。すなわち、現段階では現像を行わないが、後の工程で説明する現像・キュア工程を実施すると、当初の膜厚１５μｍに対して膜厚７．５μｍ程度の膜厚になる、つまり、５０％のポジティブ型感光性ポリイミ材料膜４がボンディングパッド２の近傍に残膜する程度の露光量である。
【００４２】
ここでは１００ｍｊ／ｃｍ2で第一の領域８の感光を行ったが、紫外線７の露光量によってポジティブ型感光性ポリイミド材料膜４の残膜をコントロール出来ることは図２から容易に推測できる。
【００４３】
第二の感光工程
次に、図４（Ｃ）に示すように、図４（Ｂ）で使用したフォトマスク２０を、通常の焦点位置になるように、半導体チップ１に対して近接移動させる。そして、このようなフォトマスク２０の移動を行ったうえで、紫外線７を露光することによってボンディングパッド２もしくは表面保護膜３の開口部に一致する第二の領域１０を感光する。本実施の形態では、表面保護膜３の開口部に合わせて第二の領域１０を形成したが、後の工程である（本実施の形態の説明では詳細の説明を省略している）ワイヤーボンディング工程での作業マージンを考慮して感光する第二の領域１０の範囲を決定する必要がある。すなわち、第二の領域１０は、第一の領域８より狭い範囲であれば本発明の目的を果たすことが出来る。
【００４４】
また、第二の領域１０を感光するための紫外線７の露光量は図２に示す４００ｍｊ／ｃｍ2以上、すなわち、残膜が０％となる露光量が適当である。具体的には、本実施の形態では、このときの紫外線の露光量は５００ｍｊ／ｃｍ2とした。これら図４（Ｂ）、図４（Ｃ）で説明した紫外線７の露光量はポジティブ型感光性ポリイミド材料膜４の特性によって変更することはいうまでもない。
【００４５】
本実施の形態では、第一，第二の感光工程で、一つのフォトマスク２０を兼用することができ、その分、半導体装置の製造に要するコストを低減することができるうえ、フォトマスクの交換に要する時間も必要なくなるので、製造コストの低減と製造時間の短縮化を図れる。
【００４６】
現像工程
次に、図４（Ｄ）に示すように、半導体ウェーハ１を回転させながら現像液ノズル１１から現像液１２をスプレーし、感光した第一の領域８、第二の領域１０を除去することによって図４（Ｄ）に示されるような段差状の切欠部１３ａのあるポジティブ型感光性ポリイミド材料膜４の開口部１３を形成する。本実施の形態では、スプレー形式の現像方法を行ったが、現像液１２を半導体ウェーハ１上に多量滴下して溶解する方法等といった現像の目的を果たすものであれば方法は問わない。
【００４７】
キュア工程
次に、図４（Ｅ）に示すように、硬化炉やオーブンを用いて半導体ウェーハ１を２００〜４００℃の温度でキュアし、ポジティブ型感光性ポリイミド材料膜４を硬化させて、ポリイミド膜からなる外部衝撃緩衝膜１９を得る。また、ポジティブ型感光性ポリイミド材料膜４はキュアを行うと硬化収縮するため本実施の形態の説明で用いたポリイミド材料の場合、第一の領域８の下方の外部衝撃緩衝膜１９の膜厚は５μｍ程度となった。また、その他の膜厚は１０μｍ程度に仕上がった。したがって、図１（Ａ）で説明した半導体ウェーハ１上に形成するポジティブ型感光性ポリイミド材料膜４の膜厚はキュア時の硬化収縮率（外部衝撃緩衝膜１９の膜厚／ポジティブ型感光性ポリイミド材料膜４の膜厚）とワイヤーボンディング工程での作業マージンを考慮して決定する。
【００４８】
また、本実施の形態では、表面保護膜３上に形成する膜としてポジティブ型感光性ポリイミド材料を用いたが、ポジティブ型の感光性レジスト材料であればどのような材料であっても同様の効果が得られることはいうまでもない。
【００４９】
なお、特許請求の範囲に示された本発明は上記した各実施の形態で説明した態様に限られるものではない。
【００５０】
また、このような開口部１３に切欠部１３ａのある外部衝撃緩衝膜１９を有する半導体装置の構成例は、実施の形態１で説明した図３と同様であるので、ここでは、説明を省略する。
【００５１】
なお、上記した第一，第二の実施の形態では、第一の感光工程を行ったのち、第二の感光工程を行っていたが、反対に、第二の感光工程を行ったのち、第一の感光工程を行っても、開口部１３の上端縁部に同様の切欠部１３ａを形成することができるのはいうまでもない。
【００５２】
【発明の効果】
以上のように、本発明によれば、ワイヤーボンディング工程でのボンディングボールとポリイミド膜の接触を回避でき、半導体装置の信頼性を高めることができる。
【図面の簡単な説明】
【図１】本発明の半導体装置の製造方法の第一の実施の形態における工程順断面図。
【図２】本発明の半導体装置の第一の実施の形態におけるポジティブ型ポリイミド膜材料の露光量と残膜率の関係を示す図。
【図３】本発明の半導体装置の製造方法で得られる半導体装置の断面図。
【図４】本発明の半導体装置の製造方法の第二の実施の形態における工程順断面図。
【図５】従来の半導体装置の製造方法の工程順断面図。
【図６】従来の半導体装置の要部断面図。
【符号の説明】
１ ・・・・半導体ウェーハ
２ ・・・・ボンディングパッド
３ ・・・・表面保護膜
４ ・・・・ポジティブ型感光性ポリイミド材料
５ ・・・・塗布ノズル
６ ・・・・第一のフォトマスク
７ ・・・・紫外線
８ ・・・・第一の領域
９ ・・・・第二のフォトマスク
１０・・・・第二の領域
１１・・・・現像ノズル
１２・・・・現像液
１３・・・・開口部[0001]
[Industrial application fields]
The present invention relates to a method for manufacturing a semi-conductor device.
[0002]
[Prior art]
In recent years, semiconductor components tend to be highly integrated and highly densified, and accordingly, semiconductor chips mounted on semiconductor devices are becoming finer and larger. On the other hand, inexpensive resin-encapsulated packages are often used as packages that are semiconductor chip cases. However, with the miniaturization and enlargement of the semiconductor chip, the semiconductor chip is strongly subjected to stress from the sealing resin. For example, the surface protection film (for example, SiO 2 ) of the semiconductor chip by the silica filler in the sealing resin. , Si 3 N 4 ) are often reported to have an accident in which a semiconductor chip becomes defective due to the occurrence of cracks, further disconnection of the wiring, and fluctuation of characteristics.
[0003]
Therefore, many semiconductor manufacturers have attempted to eliminate the above disadvantages by forming a cured resin film such as a polyimide film as an external impact buffering film for buffering external impacts on the chip surface. FIG. 5 shows a conventional example of a method for forming a polyimide film, and FIG. 6 shows a conventional structure of a semiconductor device on which a semiconductor chip using a polyimide film as an external impact buffer film is mounted.
[0004]
5 (A) to 5 (D) are enlarged views showing the cross section of the main part of the external shock absorbing film forming process. 21 is a semiconductor wafer, 22 is a bonding pad, 23 is a coating nozzle, and 24 is photosensitive. Polyimide material film, 25 photomask, 26 ultraviolet light, 27 photosensitive area, 28 developer nozzle, 29 developer, 30 opening, 31 scribe line, 32 surface protective film, 33 polyimide film An external impact buffer film made of
[0005]
First, as shown in FIG. 5A, the semiconductor wafer 21 after the predetermined process is rotated, and a photosensitive polyimide material is dropped onto the surface protective film 32 and the bonding pad 22 by the coating nozzle 23. Then, the semiconductor wafer 21 is rotated as it is for a certain period of time, and the photosensitive polyimide material is spread on the entire upper surface of the semiconductor wafer 21 to form the photosensitive polyimide material film 24.
[0006]
Next, as shown in FIG. 5B, in order to provide an opening 30 around the bonding pad 22 by using the exposure apparatus and the photomask 25, the exposure polyimide apparatus film 24 is removed at the portion where the photosensitive polyimide material film 24 is removed. Ultraviolet rays 26 are irradiated and exposed.
[0007]
Next, as shown in FIG. 5C, a developer 29 is applied or sprayed to the photosensitive polyimide material film 24 on the semiconductor wafer 21 by a developer nozzle 28 to remove the exposed region 27, and an opening portion is formed. 30 is provided.
[0008]
Next, as shown in FIG. 5D, the photosensitive polyimide material film 24 is cured at a high temperature to form an external impact buffer film 33, and the scribe line 31 is cut with a cutting machine to form a semiconductor chip.
[0009]
FIG. 6 is an enlarged view of a cross-sectional view of the main part of the semiconductor device. In the figure, 34 is a bonding ball, 35 is a bonding wire, 36 is an inner lead, 37 is an outer lead, and 38 is a sealing resin. , 39 is a crack portion of the polyimide film, and 40 is an interface peeling portion.
[0010]
In this semiconductor device, since the outer leads 37 that are directly connected to the inner leads 36 are outside the semiconductor device, an electrical signal from the inside of the semiconductor chip 21 and an electrical signal from an external substrate (not shown) are input / output. It has come to be. The manufacturing method of such a semiconductor device will be briefly described. The tip of the bonding wire 35 is electrically sparked by a wire bonder to electrically connect the bonding pad 22 and the inner lead 36 of the semiconductor chip 21 formed as described above. The bonding balls 34 are formed by melting. Then, the formed bonding ball 34 is bonded to the bonding pad 22 using heat, ultrasonic waves, and a load. In this way, one end of the bonding pad 22 and the bonding wire 35 are connected, and the other end of the bonding wire 35 is connected to the inner lead 36. Thereafter, the semiconductor chip 22 thus wire bonded is sealed with a sealing resin. By sealing with 38, the semiconductor device is completed.
[0011]
[Problems to be solved by the invention]
However, in the above-described conventional configuration, the bonding position of the bonding ball 34 may be bonded to the bonding pad when the wire bonding process is not sufficient in the wire bonding process in the semiconductor device manufacturing process, or due to equipment abnormality, operator operation or setting error. There may be a significant deviation from the center of 22. In this case, the end portion of the opening 30 of the external shock buffer film 33 and the bonding ball 34 come into contact with each other, and a crack 39 is generated at the end portion, and interface peeling occurs between the semiconductor chip 21 and the external shock buffer film 33. To do. When this interfacial peeling occurs, moisture penetrates into the peeled portion 40, causing the semiconductor chip 21 to have poor moisture resistance, and the reliability of the semiconductor device is significantly reduced.
[0012]
In view of the above problems, an object of the present invention is to provide a method of manufacturing a semiconductor device that does not cause a crack in a polyimide film due to contact even when a bonding ball is significantly displaced from the center of a bonding pad.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration.
[0015]
The method according to claim 1, the external shock absorbing film is formed on a semiconductor wafer having a bonding pad, in the manufacturing method of this external shock buffer layer on the semiconductor device obtained by forming an opening reaching the bonding pad A photosensitive material film forming step for forming a photosensitive material film serving as the external impact buffer film on the semiconductor wafer, and a first region set on the photosensitive material film corresponding to the opening from the surface. A first exposure step for selectively exposing to a middle part in the film thickness direction; and a second region on the photosensitive material film that is included in the first region and set to be smaller than the first region. , a second photosensitive step of selectively photosensitive to reach the bonding pad, the first, look including a development step in which the second region is to develop the photosensitive material film photosensitive, the first photosensitive step for The photomask used in the second exposure process is used as the photomask, and in the first exposure process, the spacing between the photomask and the semiconductor wafer is the photomask and semiconductor in the second exposure process. It is characterized in that a photomask is arranged so as to be different from the distance between the wafer and the external impact formed by the difference in the size of the first and second areas to be exposed. This has the effect that a notch is formed at the upper edge of the opening of the buffer film. In addition, one photomask can be used in both the first and second exposure steps, and accordingly, the cost required for manufacturing the semiconductor device can be reduced, and the time required for replacing the photomask is also required. It has the effect of disappearing.
[0016]
According to claim 2, in the manufacturing method of a semiconductor device according to claim 1, wherein said first photosensitive step and said second photosensitive step, has a feature that performed in reverse order, thereby, As in the first aspect, the cut-out portion is formed at the upper edge of the opening of the formed external impact buffer film.
[0018]
According to a third aspect of the present invention, in the method of manufacturing a semiconductor device according to the first or second aspect , a positive photosensitive material film is formed on the semiconductor wafer as the photosensitive material film. Can be formed easily and accurately.
[0019]
According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor device according to any one of the first to third aspects, a polyimide film is formed on the semiconductor wafer as the photosensitive material film. It is possible to form an external shock-absorbing film having a sufficient shock-absorbing performance.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0021]
First Embodiment FIGS. 1A to 1D are sectional views in order of steps in a method for manufacturing a semiconductor device according to a first embodiment of the present invention. FIG. 2 shows a relationship between the exposure amount and the remaining film rate of a general positive photosensitive polyimide material. In this embodiment, the external impact buffer film is formed from a positive photosensitive polyimide material having the characteristics shown in FIG. FIG. 3 shows an example of a semiconductor device on which an external impact buffer film that can be obtained in this embodiment is formed.
[0022]
1A to 1E, 1 is a semiconductor chip, 2 is a bonding pad, 3 is a surface protective film, 4 is a positive photosensitive polyimide material film, 5 is a coating nozzle, 6 is a first photomask, 7 is an ultraviolet ray, 8 is a first region, 9 is a second photomask, 10 is a second region, 11 is a developing nozzle, 12 is a developer, 13 is an opening, 14 is a bonding ball, and 15 is a bonding wire. , 16 is an inner lead, 17 is an outer lead, 18 is a sealing resin, and 19 is an external impact buffer film made of a polyimide film.
[0023]
Photosensitive material film forming step First, as shown in FIG. 1A, a predetermined process is completed, and a semiconductor wafer 1 having a bonding pad 2 and a surface protective film 3 having an opening in the bonding pad 2 is opened. Then, a positive photosensitive polyimide material film is dropped from above with a coating nozzle 5 and spread over the entire surface while rotating the semiconductor wafer 1 to form a positive photosensitive polyimide material film 4. The film thickness of the positive photosensitive polyimide material film 4 is determined by the number of rotations of the semiconductor wafer 1 at this time. The relationship between the rotational speed and the film thickness of the positive photosensitive polyimide material film 4 varies depending on the viscosity of the polyimide material and the like, but in this embodiment, the positive photosensitive polyimide material film is adjusted by adjusting the rotational speed. The positive photosensitive polyimide material is applied so that the film thickness of 4 is about 15 μm.
[0024]
First photosensitive step Next, as shown in FIG. 1B, the positive type photosensitive polyimide material film 4 is exposed with ultraviolet rays 7 using a first photomask 6 with a stepper or an aligner. The opening of the first photomask 6 used in this step has a planar size (hereinafter, simply referred to as a size) that largely covers the opening of the bonding pad 2 or the surface protective film 3, that is, the bonding pad 2 or the surface. It is formed to be slightly larger than the opening of the protective film 3. And the 1st photomask 6 which has such an opening is arrange | positioned so that it may be in the focus position of the ultraviolet-ray 7 to irradiate, and an opening may be in the upper position of the bonding pad 2. FIG.
[0025]
Then, the first region 8 on the positive photosensitive polyimide material film 4 is exposed through the first photomask 6 having such a shape. The exposed first region 8 has a shape equivalent to the opening of the first photomask 6, that is, a shape that largely covers the opening of the bonding pad 2 or the surface protective film 3, that is, the bonding pad 2 or the surface protective film. 3 is formed to be slightly larger than the three openings. Specifically, in the present embodiment, the first region 8 to be exposed is formed larger than the bonding pad 2 by about 5 μm. However, when the bonding pad 2 is close to other bonding pads 2, the size of the first region 8 needs to be slightly reduced. In short, there is no problem if the size of the first region 8 is made larger than that of the second region 10 exposed in the next step.
[0026]
Further, the exposure amount of the ultraviolet ray 7 for forming the first region 8 is suitably an exposure amount of 100 mj / cm 2 shown in FIG. That is, development is not performed at this stage, but when the development process and the curing process described later are performed, the film thickness is about 7.5 μm with respect to the initial film thickness of 15 μm, that is, 50% positive. The exposure amount is suitable so that the type photosensitive polyimide material film 4 remains in the vicinity of the bonding pad 2.
[0027]
Here, the first region 8 is exposed at 100 mj / cm 2 , but it can be easily estimated from FIG. 2 that the remaining film of the positive photosensitive polyimide material film 4 can be controlled by the exposure amount of the ultraviolet rays 7.
[0028]
Second exposure step Next, as shown in FIG. 1C, the second region 10 is aligned with the opening of the bonding pad 2 or the surface protective film 3 using the second photomask 9. Sensitive. The opening of the second photomask 9 used in this step is formed in the same size as the opening of the bonding pad 2 or the surface protective film 3. And the 2nd photomask 9 which has such an opening is arrange | positioned so that an opening may be in the upper position of the bonding pad 2 in the focus position of the ultraviolet-ray 7 to irradiate.
[0029]
In the present embodiment, the second region 10 is formed in accordance with the opening of the surface protective film 3, but a wire bonding process performed in a later process (detailed description is omitted in the description of the present embodiment). It is necessary to determine the size of the second region 10 in consideration of the work margin in (1). That is, if the second area 10 is smaller than the first area 8, the object of the present invention can be achieved.
[0030]
Further, the exposure amount of the ultraviolet ray 7 for forming the second region 10 is 400 mj / cm 2 or more shown in FIG. 2, that is, the exposure amount that the remaining film becomes 0% is appropriate. Specifically, in the present embodiment, the exposure amount of ultraviolet rays at this time is set to 500 mj / cm 2 . Needless to say, the exposure amount of the ultraviolet rays 7 described in FIGS. 1B and 1C is changed depending on the characteristics of the positive photosensitive polyimide material film 4.
[0031]
Development step Next, as shown in FIG. 1D, the developer 12 is sprayed from the developer nozzle 11 while rotating the semiconductor wafer 1, and the exposed first region 8 and the second region 8 are exposed. By removing the region 10, the opening 13 of the positive photosensitive polyimide material film 4 having the stepped notch 13a as shown in FIG. 1D is formed. In this embodiment, the spray type development method is performed. However, any method may be used as long as it fulfills the purpose of development, such as a method in which a large amount of developer 12 is dropped onto the semiconductor wafer 1 and dissolved.
[0032]
Curing step Next, as shown in FIG. 1E, the semiconductor wafer 1 is cured at a temperature of 200 to 400 [deg.] C. using a curing furnace or oven to cure the positive photosensitive polyimide material film 4. Thus, the external impact buffer film 19 made of a polyimide film is obtained. Further, since the positive photosensitive polyimide material film 4 cures and shrinks when cured, in the case of the polyimide material used in the description of the present embodiment, the film of the polyimide film 19 located below the periphery of the first region 8. The thickness was about 5 μm. Other film thicknesses were finished to about 10 μm. Accordingly, the film thickness of the positive photosensitive polyimide material film 4 formed on the semiconductor wafer 1 described with reference to FIG. 1A is the curing shrinkage ratio during curing (the film thickness of the external impact buffer film 19 / positive photosensitive polyimide). The thickness is determined in consideration of the film thickness of the material film 4 and the work margin in the wire bonding process.
[0033]
FIG. 3 shows an example of a semiconductor device having the external shock-absorbing film 19 in which the opening 13 has a notch 13a. In this example, the bonding pad 2 is 100 μm □, and the bonding ball 14 after wire bonding has a cross-sectional diameter of about 90 μm and a thickness of about 20 μm. In this case, in the conventional shape, the end of the opening 13 and the end of the bonding ball 14 are in contact with each other. However, as in the present invention, a notch 13a having a width of 5 μm and a thickness of 5 μm is provided around the bonding pad 2. Then, the end of the opening 13 and the end of the bonding ball 14 are not in contact with each other, and therefore the margin of deviation of the bonding ball 14 from the center of the bonding pad 2 can be set to be 3 to 5 μm larger. I understand.
[0034]
Second embodiment Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
[0035]
FIG. 4 shows cross-sectional views in the order of steps in the method for manufacturing a semiconductor device of the present embodiment.
[0036]
4A to 4E, 1 is a semiconductor chip, 2 is a bonding pad, 3 is a surface protective film, 4 is a positive photosensitive polyimide material film, 5 is a coating nozzle, 7 is ultraviolet light, and 8 is first. , 10 is a second region, 11 is a developing nozzle, 12 is a developer, 13 is an opening, 19 is a polyimide film, and 20 is a photomask.
[0037]
Photosensitive material film forming step First, as shown in FIG. 4A, a predetermined process is completed, and a semiconductor wafer 1 having a bonding pad 2 and a surface protection film 3 having an opening in the bonding pad 2 is opened. Then, a positive photosensitive polyimide material film is dropped from above with a coating nozzle 5 and spread over the entire surface while rotating the semiconductor wafer 1 to form a positive photosensitive polyimide material film 4. The film thickness of the positive photosensitive polyimide material film 4 is determined by the number of rotations of the semiconductor wafer 1 at this time. Although the relationship between the rotational speed and the film thickness of the positive photosensitive polyimide material film 4 varies depending on the viscosity of the positive photosensitive polyimide material, etc., in this embodiment, the positive photosensitive properties can be achieved by adjusting the rotational speed. A positive photosensitive polyimide material was applied so that the thickness of the material film 4 was about 15 μm.
[0038]
First photosensitive step Next, as shown in FIG. 4B, the positive photosensitive polyimide material film 4 is exposed to ultraviolet rays 7 using a photomask 20 with a stepper or an aligner. The opening of the photomask 20 used in this step is formed to have substantially the same size as the opening of the bonding pad 2 or the surface protective film 3. Then, the photomask 20 having such an opening is disposed so as to be positioned above the opening of the bonding pad 2 or the surface protective film 3. Furthermore, in this step, the photomask 20 is shifted from the semiconductor wafer 1 by a distance larger than the focal distance of the normal ultraviolet light 7, that is, the separation distance between the photomask 20 and the semiconductor wafer 1 is larger than the focal distance of the normal ultraviolet light 7. In the opened state, the positive photosensitive polyimide material film 4 is exposed.
[0039]
Specifically, in the present embodiment, the photomask 20 is disposed in a position where the photomask 20 is disposed at a position spaced from the surface of the positive photosensitive polyimide material film 4 by 15 μm from the focal position of the normal ultraviolet ray 7. The first region 8 on the mold type photosensitive polyimide material film 4 is exposed. When exposure is performed in such a state, leakage of the ultraviolet rays 7 occurs in the photomask 20 and light shielding is incomplete, and an area larger than the exposure area at the normal focal position of the photomask 20 can be exposed. .
[0040]
Therefore, by this step, the first region 8 on the positive photosensitive polyimide material film 4 exposed through the photomask 20 has a shape slightly larger than the opening of the photomask 20, that is, the bonding pad 2 or the surface protection. The opening of the film 3 is greatly included, that is, slightly larger than the opening of the bonding pad 2 or the protective film 3. Specifically, in the present embodiment, the exposed first region 8 is formed to be approximately 5 μm around the bonding pad 2. However, when the bonding pad 2 is close to another bonding pad 2, the size of the first region 8 needs to be reduced. There is no problem if the size of the first region 8 is larger than the second region 10 to be exposed in the next step.
[0041]
Further, the exposure amount of the ultraviolet ray 7 for sensitizing the first region 8 is suitably an exposure amount of 100 mj / cm 2 shown in FIG. In other words, development is not performed at this stage, but when the development and cure process described in the later steps is performed, the film thickness becomes about 7.5 μm with respect to the initial film thickness of 15 μm, that is, 50%. The exposure amount is such that the positive photosensitive polyimide material film 4 remains in the vicinity of the bonding pad 2.
[0042]
Here, the first region 8 is exposed at 100 mj / cm 2 , but it can be easily estimated from FIG. 2 that the remaining film of the positive photosensitive polyimide material film 4 can be controlled by the exposure amount of the ultraviolet rays 7.
[0043]
Second exposure step Next, as shown in FIG. 4C, the photomask 20 used in FIG. 4B is placed on the semiconductor chip 1 so as to be at a normal focal position. Move close. Then, after such movement of the photomask 20, the second region 10 that coincides with the opening of the bonding pad 2 or the surface protective film 3 is exposed by exposing the ultraviolet rays 7. In the present embodiment, the second region 10 is formed in accordance with the opening of the surface protective film 3, but this is a later process (detailed description is omitted in the description of the present embodiment). It is necessary to determine the range of the second region 10 to be exposed in consideration of the work margin in the process. That is, if the second region 10 is narrower than the first region 8, the object of the present invention can be achieved.
[0044]
Further, the exposure amount of the ultraviolet ray 7 for sensitizing the second region 10 is 400 mj / cm 2 or more shown in FIG. 2, that is, the exposure amount at which the remaining film becomes 0% is appropriate. Specifically, in the present embodiment, the exposure amount of ultraviolet rays at this time is set to 500 mj / cm 2 . Needless to say, the exposure amount of the ultraviolet rays 7 described in FIGS. 4B and 4C is changed according to the characteristics of the positive photosensitive polyimide material film 4.
[0045]
In the present embodiment, one photomask 20 can be used in both the first and second exposure steps, and accordingly, the cost required for manufacturing the semiconductor device can be reduced and the photomask can be replaced. This eliminates the need for the time required to reduce the manufacturing cost and the manufacturing time.
[0046]
Development process Next, as shown in FIG. 4D, the developing solution 12 is sprayed from the developing solution nozzle 11 while rotating the semiconductor wafer 1, and the exposed first region 8 and the second region are exposed. By removing 10, the opening 13 of the positive photosensitive polyimide material film 4 having the stepped notch 13 a as shown in FIG. 4D is formed. In this embodiment, the spray type development method is performed. However, any method may be used as long as it fulfills the purpose of development such as a method in which a large amount of developer 12 is dropped onto the semiconductor wafer 1 and dissolved.
[0047]
Curing step Next, as shown in FIG. 4 (E), the semiconductor wafer 1 is cured at a temperature of 200 to 400 [deg.] C. using a curing furnace or oven to cure the positive photosensitive polyimide material film 4. Thus, an external impact buffer film 19 made of a polyimide film is obtained. In addition, since the positive photosensitive polyimide material film 4 cures and shrinks when cured, in the case of the polyimide material used in the description of the present embodiment, the film thickness of the external impact buffer film 19 below the first region 8 is It was about 5 μm. Other film thicknesses were finished to about 10 μm. Accordingly, the film thickness of the positive photosensitive polyimide material film 4 formed on the semiconductor wafer 1 described with reference to FIG. 1A is the curing shrinkage ratio during curing (the film thickness of the external impact buffer film 19 / positive photosensitive polyimide). The thickness is determined in consideration of the film thickness of the material film 4 and the work margin in the wire bonding process.
[0048]
In the present embodiment, a positive photosensitive polyimide material is used as a film formed on the surface protective film 3, but the same effect can be obtained with any positive photosensitive resist material. Needless to say, is obtained.
[0049]
In addition, this invention shown by the claim is not restricted to the aspect demonstrated by each above-mentioned embodiment.
[0050]
In addition, the configuration example of the semiconductor device having the external impact buffer film 19 having the notch 13a in the opening 13 is the same as that in FIG. 3 described in the first embodiment, and thus the description thereof is omitted here. .
[0051]
In the first and second embodiments described above, the second exposure process is performed after the first exposure process. Conversely, after the second exposure process is performed, the first exposure process is performed. It goes without saying that the same notch 13a can be formed at the upper edge of the opening 13 even if one exposure process is performed.
[0052]
【The invention's effect】
As described above, according to the present invention, the contact between the bonding ball and the polyimide film in the wire bonding process can be avoided, and the reliability of the semiconductor device can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view in order of steps in a first embodiment of a method for manufacturing a semiconductor device of the present invention.
FIG. 2 is a view showing a relationship between an exposure amount of a positive polyimide film material and a remaining film ratio in the first embodiment of the semiconductor device of the present invention.
FIG. 3 is a cross-sectional view of a semiconductor device obtained by the method for manufacturing a semiconductor device of the present invention.
FIG. 4 is a cross-sectional view in order of steps in the second embodiment of the method for manufacturing a semiconductor device of the present invention.
FIG. 5 is a cross-sectional view in order of steps of a conventional method for manufacturing a semiconductor device.
FIG. 6 is a cross-sectional view of a main part of a conventional semiconductor device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer 2 ... Bonding pad 3 ... Surface protective film 4 ... Positive photosensitive polyimide material 5 ... Coating nozzle 6 ... First photomask 7 ··· UV 8 ··· First region 9 ··· Second photomask 10 ··· Second region 11 ··· Development nozzle 12 ··· Developer 13 · · · ···Aperture

Claims (4)

ボンディングパッドを有する半導体ウェーハ上に外部衝撃緩衝膜を形成し、この外部衝撃緩衝膜に前記ボンディングパットに達する開口を形成してなる半導体装置の製造方法であって、
半導体ウェーハ上に、前記外部衝撃緩衝膜となる感光性材料膜を形成する感光性材料膜形成工程と、
前記ボンディングパットに対応して前記感光性材料膜上に設定した第一の領域を表面から膜厚方向中途部まで選択的に感光させる第一の感光工程と、
前記第一の領域内に含まれ、かつ前記第一の領域より小さく設定した感光性材料膜上の第二の領域を、前記ボンディングパットに達するまで選択的に感光させる第二の感光工程と、
第一，第二の領域が感光した感光性材料膜を現像する現像工程と、
を含み、
前記第一の感光工程に用いるフォトマスクとして、前記第二の感光工程に用いるフォトマスクを用い、かつ、第一の感光工程では、フォトマスクと半導体ウェーハとの間の離間間隔が第二の感光工程でのフォトマスクと半導体ウェーハとの離間間隔とは異なるように、フォトマスクを配置することを特徴とする半導体装置の製造方法。 An external impact buffer film is formed on a semiconductor wafer having a bonding pad, and an opening reaching the bonding pad is formed in the external impact buffer film.
A photosensitive material film forming step of forming a photosensitive material film serving as the external impact buffer film on a semiconductor wafer;
A first exposure step of selectively exposing a first region set on the photosensitive material film corresponding to the bonding pad from the surface to the middle in the film thickness direction;
A second exposure step for selectively exposing a second region on the photosensitive material film contained within the first region and set smaller than the first region until reaching the bonding pad;
A developing process for developing the photosensitive material film in which the first and second regions are exposed;
Only including,
As the photomask used in the first exposure process, the photomask used in the second exposure process is used, and in the first exposure process, the separation interval between the photomask and the semiconductor wafer is the second exposure process. A method for manufacturing a semiconductor device, comprising arranging a photomask so that a spacing between the photomask and the semiconductor wafer in the process is different. 請求項１記載の半導体装置の製造方法であって、
前記第一の感光工程と前記第二の感光工程とを、逆の順序で行うことを特徴とする半導体装置の製造方法。A method of manufacturing a semiconductor device according to claim 1 ,
A method of manufacturing a semiconductor device, wherein the first exposure step and the second exposure step are performed in reverse order. 請求項１または２のいずれか記載の半導体装置の製造方法であって、
感光性材料膜として、ポジ型感光材料膜を半導体ウェーハ上に形成することを特徴とする半導体装置の製造方法。A method for manufacturing a semiconductor device according to claim 1 , wherein:
A method of manufacturing a semiconductor device, comprising forming a positive photosensitive material film as a photosensitive material film on a semiconductor wafer. 請求項１ないし３のいずれか記載の半導体装置の製造方法であって、
感光性材料膜として、ポリイミド膜を半導体ウェーハ上に形成することを特徴とする半導体装置の製造方法。A method of manufacturing a semiconductor device according to any one of claims 1 to 3 ,
A method for manufacturing a semiconductor device, comprising forming a polyimide film on a semiconductor wafer as a photosensitive material film.
JP35061097A 1997-12-19 1997-12-19 Manufacturing method of semiconductor device Expired - Fee Related JP3751731B2 (en)

Priority Applications (1)

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