JP2004225129A

JP2004225129A - Plating method and plating device

Info

Publication number: JP2004225129A
Application number: JP2003016270A
Authority: JP
Inventors: Rei Kokai; 冷黄海; Fumio Kuriyama; 文夫栗山; Nobutoshi Saito; 信利齋藤
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2003-01-24
Filing date: 2003-01-24
Publication date: 2004-08-12

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating method and a plating device with which the applied electric potential distribution is freely and finely adjusted at a low cost when performing plating on a substrate surface to be plated, and a plating film of uniform film thickness is deposited on the substrate surface without requiring any complicated operation method. <P>SOLUTION: In the plating device in which an anode 14 and a substrate W to be plated are disposed facing each other and immersed in a plating solution 10 in a plating tank 11 holding the plating solution 10. An adjustment plate 21 is disposed between the anode 14 and the substrate W, and the substrate W is plated by performing energization between the anode 14 and the substrate W, the adjustment plate 21 is formed of a dielectric material, and a through hole group distribution adjustment means having a through hole group consisting of a large number of through holes 24 penetrated from the surface on the substrate side to the anode side surface to adjust the condition of distribution of the through hole group of the adjustment plate 21 is provided. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は半導体ウエハ等の被めっき基板の表面にめっきするめっき装置に関し、特に半導体ウエハの表面に設けられた微細な配線用溝やホール、レジスト開口部にめっき膜を形成したり、半導体ウエハの表面にパッケージの電極等と電気的に接続するバンプ（突起状電極）を形成したりするのに好適なめっき方法及びめっき装置に関するものである。
【０００２】
【従来の技術】
例えば、ＴＡＢ（ＴａｐｅＡｕｔｏｍａｔｅｄＢｏｎｄｉｎｇ）やフリップチップにおいては、配線が形成された半導体チップの表面の所定箇所（電極）に金、銅、はんだ、或いはニッケル、更にこれらを多層に積層した突起状接続電極（バンプ）を形成し、このバンプを介してパッケージの電極やＴＡＢ電極と電気的に接続することが広く行われている。このバンプ形成方法としては、電気めっき法、蒸着法、印刷法、ボールバンプ法といった種々の手法があるが、半導体チップのＩ／Ｏ数の増加、ピッチの微細化に伴い、微細化可能で性能が比較的安定している電気めっき法が多く用いられている。
【０００３】
電気めっき法によれば、高純度の金属膜（めっき膜）が容易に得られ、しかも金属膜の成膜速度が比較的速いばかりではなく、金属膜の厚みの制御も比較的容易に行うことができる。また、半導体ウエハ上への金属膜形成においては、膜厚だけではなく、高密度実装、高性能化及び高い歩留まりを追求するには、膜厚の半導体ウエハ面内均一性も厳しく要求されている。電気めっきの膜厚分布は、めっき液の金属イオン供給速度分布や電位分布を均一にすることにより、優れた均一膜を得ることが期待されてきた。
【０００４】
図１７は、いわゆるフェースダウン方式を採用した従来のめっき装置の一構成例を示す図である。このめっき装置は、内部にめっき液１１０を保有する上方が開口しためっき槽１１１と、半導体ウエハ等の被めっき基板Ｗをその表面（被めっき面）を下向き（フェースダウン）にして着脱自在に保持する上下動自在な基板ホルダ１１２を有している。めっき槽１１１の底部には、アノード１１３が水平に配置され、上部の周囲には、オーバーフロー槽１１４が設けられ、更にめっき槽１１１の底部にめっき液供給ノズル１１５が設けられている。
【０００５】
基板ホルダ１１２で水平に保持した被めっき基板Ｗを、めっき槽１１１の上端開口部を塞ぐ位置に配置し、この状態で、めっき液供給ノズル１１５からめっき槽１１１の内部にめっき液１１０を供給し、このめっき液１１０をめっき槽１１１の上部からオーバーフローさせることで、基板ホルダ１１２で保持した被めっき基板Ｗの表面にめっき液１１０を接触させ、同時に、導線１１６を介してアノード１１３をめっき電源１１８の陽極に接続し、導線１１７を介して被めっき基板Ｗをめっき電源１１８の陰極に接続し、被めっき基板Ｗとアノード１１３の間に所定のめっき電圧を印加する。これにより被めっき基板Ｗとアノード１１３との電位差により、めっき液１１０中の金属イオンが被めっき基板Ｗの表面より電子を受取り、被めっき基板Ｗの表面に金属が析出して金属膜が形成される。
【０００６】
上記構成のめっき装置によれば、アノード１１３の大きさ、アノード１１３と被めっき基板Ｗとの極間距離及び電位差、めっき液供給ノズル１１５から供給されるめっき液１１０の供給速度などを調整することにより、被めっき基板Ｗの表面に形成される金属膜の膜厚の均一性をある程度調節することができる。
【０００７】
図１８は、いわゆるディップ方式を採用した従来のめっき装置の一構成例を示す図である。このめっき装置は、内部にめっき液を保有するめっき槽１２０を有し、該めっき槽１２０内に基板ホルダ１２１に周縁部を水密的にシールして保持した被めっき基板Ｗと、アノードホルダ１２４に保持されたアノード１２２とが互いに対向して垂直に配置されている。そしてアノード１２２と被めっき基板Ｗの間に位置するように中央に中央孔１２３ａが形成された誘電体からなる調整板（レギュレーションプレート）１２３が配置されている。
【０００８】
めっき槽１２０内にめっき液を収容し、アノード１２２、被めっき基板Ｗ及び調整板１２３をめっき液中に浸漬し、同時に導線１２５を介してアノード１２２をめっき電源１２７の陽極に接続し、導線１２６を介して被めっき基板Ｗをめっき電源１２７の陰極に接続し、アノード１２２と被めっき基板Ｗの間に所定のめっき電圧を印加することにより、前述と同様にして、被めっき基板Ｗの表面に金属が析出して金属膜が形成される。
【０００９】
上記構成のめっき装置によれば、アノード１２２と該アノード１２２との対向する位置に配置される被めっき基板Ｗとの間に、中央孔１２３ａを有する調整板１２３を配置し、この調整板１２３でめっき槽１２０内の電位分布を調節することで、被めっき基板Ｗの表面に形成される金属膜の膜厚分布をある程度調節することができる。
【００１０】
図１９は、いわゆるディップ方式を採用した従来のめっき装置の他の構成例を示す図である。このめっき装置が図１８に示すめっき装置と異なる点は、アノード１２２と被めっき基板Ｗの間に調整板１２３を備えることなく、リング状の擬似陰極１３０を備え、被めっき基板Ｗの周囲に該擬似陰極１３０を配置した状態で、被めっき基板Ｗを基板ホルダ１２１に保持し、更に、めっき処理に際し、導線１３１を介して、擬似陰極１３０をめっき電源１２７の陰極に接続するようにした点にある。このめっき装置によれば、擬似陰極１３０の電位を調節することで、被めっき基板Ｗの表面に形成される金属膜の膜厚の均一性を改善することができる。なお、図１９において、図１８と同一符号を付した部分は同一又は相当部分を示す。
【００１１】
例えば、半導体ウエハを被めっき基板Ｗとして説明すれば、被めっき基板の表面に配線用やバンプなどの金属膜（めっき膜）を形成するにあたって、被めっき基板Ｗの全面に亘る金属膜の膜厚の均一性が厳しく要求されるが、上記従来のめっき装置では、このような要求を満たす金属膜を形成することがかなり困難であった。例えば、図１７に示す構成のめっき装置で被めっき基板Ｗにめっきを行うと、めっき液１１０の流れの影響を強く受けた金属膜が形成され、このめっき液の流れが速いと、図２０（ａ）のように金属イオンの供給が十分な被めっき基板Ｗの中央部の方が周辺部よりも金属膜Ｐの膜厚が厚くなる傾向が生じる。これを防止するため、めっき液１１０の流れを非常に遅くすると、図２０（ｂ）に示すように、被めっき基板Ｗの周縁部の方が中央部より金属膜Ｐの膜厚が厚くなる傾向が生じる。
【００１２】
また、図１８に示すめっき装置で被めっき基板Ｗにめっきを行うと、中央に中央孔１２３ａを有する調整板１２３により電位分布を改善して、被めっき基板Ｗの全面に亘る金属膜の膜厚分布の均一性をある程度改善できるものの、図２０（ｃ）に示すように、被めっき基板Ｗの中央部及び周辺部で金属膜Ｐの膜厚が厚くなる。即ち、波打ったような膜厚分布を有する金属膜Ｐが形成される傾向が生じる。
【００１３】
また、被めっき基板Ｗの上下、或いは左右の領域において金属膜Ｐの膜厚が大きく異なることは生産現場ではよくある。偏った波のような膜厚分布を有する金属膜Ｐが形成される傾向も良く見られる。更に図１９に示すめっき装置でめっきを行った場合には、擬似電極１３０の電圧の調整が困難であるばかりでなく、擬似電極１３０の表面に付着した金属膜を除去する必要が生じ、この操作がかなり煩雑となってしまう。
【００１４】
従来のめっき装置は、それぞれの構成の特徴により、それぞれ異なるめっき膜厚分布を示し、良好でかつ均一なめっき膜を得ることが難しかった。その理由は、第一に装置の集積化によりめっき槽ができる限り小さくされているため、槽内の電場境界効果による電場の不均一性があるためである。調整板を用いてその不均一性をある程度緩和させることはできるが、めっき槽内の被めっき基板を保持する基板ホルダなどの固定機構、めっき液の攪拌機構、陰極である被めっき基板の導通接点の状況、被めっき基板下地の抵抗、被めっき基板の開口エリア及びパターンの分布等の諸因子によって引き起した電場の不均一性が多様である。
【００１５】
第二に陰極である被めっき基板の表面において、深いレジストパターンのホールには、各ホール内に流れている電解質の金属イオン分布が不均一になり易いと考えられる。攪拌することによって槽内電解質の流れが限られている槽内空間内で多数の渦流となり、槽内のめっき液の不均一性の改善が見られるが、被めっき基板のパターン近辺の局所的場所をみると、金属イオンの分布はレジスト材料、パターンの形状、めっき条件、渦流大きさと分布によって依然不均一であることがわかる。つまり、金属イオンの均一な分布は両電極間の電場強度の分布だけに依存することではなく、レジストパターンと攪拌条件などにも依存している。
【００１６】
生産ラインにおいては、様々の影響因子が条件毎に変動しているにもかかわらず、従来のめっき装置では、殆ど対称性を持つ調整板或いは擬似陰極などの固定的なものを用いて対応を講じているが、被めっき基板の多様性の傾向にある生産状況の変化に対応することが困難であった。また、生産状況の解析から装置の改造製作、プロセスチューニングを完成するまで、長い時間又は高いコストを必要とする。
【００１７】
また、半導体デバイス製造産業において、半導体ウエハ面上のめっき皮膜の膜厚均一性βの評価は、
β＝（Ｔ_ｍａｘ−Ｔ_ｍｉｎ）／（Ｔ_ｍａｘ＋Ｔ_ｍｉｎ）（１）
但し、Ｔ_ｍａｘはめっき皮膜の最大厚み、Ｔ_ｍｉｎはめっき皮膜の最小厚みである。式（１）を用いて行うのが普通なので、半導体ウエハ表面の均一性は個別の異常値に大きく影響されることとなっている。対称性を有する調整板などをベースに、半導体ウエハ生産のプロセスチューニングに応じて、具体的な局所的、非対称的な対策も必要である。
【００１８】
【特許文献１】
特開平１１−１５２６００号公報
【特許文献２】
特開平１１−１９３４９７号公報
【００１９】
【発明が解決しようとする課題】
本発明は上述の点に鑑みてなされたもので、半導体ウエハ等の被めっき基板面上にめっきを行う場合に印加する電位分布を自由にきめ細く調整できる低コストで、しかも複雑な運転方法を必要とせず、被めっき基板面上に均一な膜厚のめっき膜を形成できるめっき方法及びめっき装置を提供することを目的とする。
【００２０】
【課題を解決するための手段】
上記課題を解決するため請求項１に記載の発明は、めっき液を保有するめっき槽の該めっき液に浸漬させてアノードと被めっき体を対向して配置すると共に、アノードと被めっき体との間に調整板を配置し、アノードと被めっき体との間に通電して被めっき体にめっきを行うめっき方法において、調整板は誘電体材からなり、該調整板に被めっき体側面からアノード側面に貫通する多数の通孔からなる通孔群を有し、調整板の通孔群の分布状態を調整し、アノードと被めっき体の間の電場分布を調整し、被めっき体のめっき膜厚を調整することを特徴とする。
【００２１】
上記調整板の通孔群の分布状態を調整することにより、この通孔内を電場が漏れ、漏れた電場が均一に拡がるように分布状態を調整することができ、被めっき体に形成される金属膜の面内均一性をより高めることができる。また、調整板の通孔群の分布状態を調整することにより、多数の通孔を通過するめっき液の流れを抑制し、このめっき液の流れにより影響を受けて、被めっき体に形成される金属膜の膜厚に不均一が生じることを防止することができる。また、被めっき体面内において、めっきのテストバンプの高さ分布の結果から、調整板上の通孔群の分布をそれに応じて自由に変え、バンプのより高い均一性が得られるように簡単に調整することができる。
【００２２】
請求項２に記載の発明は、めっき液を保有するめっき槽の該めっき液に浸漬させてアノードと被めっき体を対向して配置すると共に、アノードと被めっき体との間に調整板を配置し、アノードと被めっき体との間に通電して被めっき体にめっきを行うめっき装置において、調整板は誘電体材からなり、被めっき体側面からアノード側面に貫通する多数の通孔から成る通孔群を有し、調整板の通孔群の分布状態を調整する通孔群分布調整手段を設けたことを特徴とする。
【００２３】
上記のように通孔群分布調整手段を設けたことにより、請求項１に記載の発明と同様、被めっき体に形成される金属膜の面内均一性をより高めること、めっき液の流れにより影響を受けて被めっき体に形成される金属膜の膜厚に不均一が生じることを防止すること、めっきのテストバンプの高さ分布の結果からバンプのより高い均一性が得られるように簡単に調整することができる。また、これらは生産現場でめっき装置の実運転に先立って予め調整板の通孔群の分布状態を調整して行うことができ、被めっき体に均一な膜厚のめっき膜を形成することが容易になる。
【００２４】
請求項３に記載の発明は、請求項２に記載のめっき装置において、通孔群分布調整手段は通孔群の通孔を開閉する孔開閉手段を有し、該孔開閉手段で通孔群の分布状態を調整する手段であることを特徴とする。
【００２５】
上記のように調整板の通孔群を多数の通孔の組み合わせで形成するので、生産性を向上させることができる。この場合、細孔の径は一般的には１〜６０ｍｍであり、好ましくは２〜１０ｍｍ程度である。その細孔間のスペースは一般的には２〜５０ｍｍであり、好ましくは２〜１０ｍｍである。また、孔開閉手段で通孔を開閉して通孔群の分布状態を調整するので、調整板を替えることなく、通孔群の分布状態の調整が可能となる。
【００２６】
請求項４に記載の発明は、請求項３に記載のめっき装置において、孔開閉手段は、孔を薄板又は挿入材で塞ぐように構成されていることを特徴とする。
【００２７】
上記のように孔開閉手段は薄板又は挿入材で孔を塞ぐように構成されているから、例えば半導体デバイスの生産ラインの実情を反映できる調整板によって通孔群の分布状態を調整し、めっき体面上に均一な膜厚の良好なめっき膜を形成できる。
【００２８】
請求項５に記載の発明は、請求項２乃至４のいずれか１項に記載のめっき装置において、アノードと被めっき体との間のめっき液を攪拌するめっき液攪拌手段を設けたことを特徴とする。
【００２９】
上記のようにめっき液攪拌手段を設け、該めっき液攪拌手段でアノードと被めっき体との間のめっき液を攪拌することにより、十分な金属イオンを被めっき体に均一に供給でき、より均一な膜厚の金属めっき膜を形成することができる。また、めっき液攪拌手段として往復運動するパドル型攪拌機構を用いてめっき液を攪拌することにより、めっき液の流れに方向性をなくしながら十分な金属イオンを被めっき体に均一に供給することができる。
【００３０】
【発明の実施の形態】
以下、本発明の実施の形態例を図面に基づいて説明する。図１及び図２は本発明に係るめっき装置の構成を示す図である。本めっき装置は図１及び図２に示すように、内部にめっき液１０を保持するめっき槽１１を具備し、該めっき槽１１内に基板ホルダ１２に装着された被めっき基板Ｗと、アノードホルダ１３に装着されたアノード１４が対向して配置されている。被めっき基板Ｗは円板状でその周縁部を水密的にシールし、且つ表面（被めっき面）を露出させて基板ホルダ１２に脱着自在に保持されている。また、基板ホルダ１２は上下動自在となっている。
【００３１】
めっき槽１１の両側方には、このめっき槽１１の溢流堰１５の上端をオーバーフローしためっき液１０を流すオーバーフロー槽１６が設けられ、該オーバーフロー槽１６とめっき槽１１とは循環配管１７で結ばれている。該循環配管１７には循環ポンプ１８、恒温ユニット１９及びフィルタ２０が直列に接続されている。循環ポンプ１８の駆動によりめっき槽１１内に供給されためっき液１０は、めっき槽１１の内部を満たし、しかる後、溢流堰１５からオーバーフローしてオーバーフロー槽１６内に流れ込み、循環ポンプ１８に戻って循環するように構成されている。
【００３２】
アノード１４の形状は、被めっき基板Ｗの形状に沿って円形で、該アノード１４と被めっき基板Ｗは、めっき槽１１内にめっき液１０を満たした時に、このめっき液１０中に浸漬されるようになっている。更に、アノード１４と基板ホルダ１２との間に位置して、めっき槽１１の内部をアノード側室１１ａと被めっき基板側室１１ｂに仕切り、めっき槽１１内に保持されるめっき液１０をアノード側と被めっき基板側に遮断する調整板２１が設置されている。
【００３３】
基板ホルダ１２と調整板２１との間には、下方に垂下する複数のパドル２２を備え、このパドル２２が被めっき基板側室１１ｂ内のめっき液１０内部に位置して、基板ホルダ１２で保持された被めっき基板Ｗと平行に往復動することで、被めっき基板側室１１ｂ内のめっき液１０を攪拌する攪拌機構２３が配置されている。
【００３４】
調整板２１は、例えば肉厚が０．５〜１０ｍｍ程度で、ＰＶＣ、ＰＰ、ＰＥＥＫ、ＰＥＳ、ＨＴ−ＰＶＣ、ＰＦＡ、ＰＴＦＥ、その他の樹脂系材料からなる誘電体から構成されている。そして、この調整板２１の内部の所定の領域、即ち被めっき基板Ｗを基板ホルダ１２で保持してめっき槽１１内の所定のめっき位置に配置した時に、この被めっき基板Ｗの表面と対面する領域の略全域に亘り、かつ被めっき基板Ｗと相似形な円形領域内に、多数の通孔２４からなる通孔群２５が設けられている。
【００３５】
調整板２１はここでは、図３に詳細に示すように、通孔群２５は細いスリット状の通孔（細孔）２４を円形領域に均等に分布させて形成した構成である。この通孔２４の直径は、この例では２ｍｍに設定され、ここでは、合計６３３個も設けられている。この通孔２４の径は、一般的には、１〜６０ｍｍの範囲で任意に設定されるが、好ましくは２〜１０ｍｍ程度である。
【００３６】
上記のように、調整板２１の内部に多数の通孔２４からなる通孔群２５を設け、めっき処理する際に、この各通孔２４内を通って電場が形成され、形成された電場が均一に広がるようにすることで、被めっき基板Ｗの表面（被めっき面）の全面に亘る電位分布をより均一にして、被めっき基板Ｗの表面に形成される金属膜の面内均一性をより高めることができる。また、めっき液１０がめっき槽１１内に設置した調整板２１の内部に設けた多数の通孔２４内を通過するのを抑制することで、このめっき液１０の流れ（めっき液の戻り）による影響を受けて、被めっき基板Ｗの表面に形成される金属膜の膜厚に不均一が生じることを防止することができる。
【００３７】
特に、この通孔２４内のめっき液１０の流通を抑制しつつ、電場の漏れを促進することができる。更に、調整板２１の被めっき基板Ｗの表面と対面する領域の略全域に亘り、かつ被めっき基板Ｗと相似形な円形領域に、多数の通孔２４からなる通孔群２５を形成することで、被めっき基板Ｗの表面の全ての方向に対して良好な膜厚均一性を有する金属膜を形成することができる。
【００３８】
この例によれば、先ず、前述のようにして、めっき槽１１の内部にめっき液１０を満たし、めっき液１０を循環させておく。この状態で、被めっき基板Ｗを保持した基板ホルダ１２を降下させて、被めっき基板Ｗをめっき槽１１内のめっき液１０に浸漬した所定の位置に配置する。この状態で、導線２６を介してアノード１４をめっき電源２８の陽極に、導線２７を介して被めっき基板Ｗをめっき電源２８の陰極にそれぞれ接続し、同時に攪拌機構２３を駆動してパドル２２を被めっき基板Ｗの表面に沿って往復動させて被めっき基板側室１１ｂ内のめっき液１０を攪拌し、これによって、被めっき基板Ｗの表面に金属を析出させて金属膜を形成する。
【００３９】
この時、前述のように、調整板２１の内部に設けた多数の通孔２４内を電場が漏れ、漏れた電場が均一に拡がるようにすることで、被めっき基板Ｗの表面（被めっき表面）の全面に亘る電位分布をより均一にして、図４に示すように、被めっき基板Ｗの表面に面内均一性をよく高めた金属膜Ｐを形成することができる。しかも、被めっき基板Ｗと調整板２１との間のめっき液１０をめっき処理中にパドル２２によって攪拌することで、めっき液１０の流れに方向性をなくしながら、十分な金属イオンを被めっき基板の表面に均一に供給して、より均一な膜厚の金属膜をより迅速に形成することができる。
【００４０】
ここで、上記調整板２１に重ね合せるように図５に示す構成の遮蔽板３０を配置する。遮蔽板３０はカメラの絞りのような機構を有し、その中央開孔３０ａの径がレバー３１を矢印Ａ、Ｂに示すように操作することにより、拡大、縮小するようになっている。この遮蔽板３０をその中央開孔３０ａが調整板２１の通孔群２５が設けられている円形領域と同心円状になるように配置する。これにより、レバー３１を操作して通孔群の分布状態（通孔群の面積）を調整することができる。
【００４１】
上記のように通孔群２５の分布状態を調整することにより、この通孔２４内を電場が漏れ、漏れた電場が均一に拡がるように分布状態を調整することができ、被めっき基板Ｗに形成される金属膜の面内均一性をより高めることができる。また、調整板２１の通孔群２５の分布状態を調整することにより、多数の通孔２４を通過するめっき液の流れを抑制し、このめっき液の流れにより影響を受けて、被めっき基板Ｗに形成される金属膜の膜厚に不均一が生じることを防止することができる。また、被めっき基板Ｗ面内において、めっきのテストバンプの高さ分布の結果から、調整板２１上の通孔群２５の分布をそれに応じて自由に変え、バンプのより高い均一性が得られるように調整することができる。
【００４２】
なお、上記例では通孔群２５の分布状態を調整するのに、カメラの絞りのような機構を有する遮蔽板３０を用い、その中央開孔３０ａの径を調整して通孔群２５の開閉する通孔２４の量を変化させているが、通孔群２５の分布状態の調整としてはこれに限定されるものではなく、図６に断面構成を示すように、通孔２４に塊状の挿入部材３２を挿入若しくは外すことによって構成してもよい。また、図７に示すように、薄板部３３に通孔２４に貫通させるネジ部３４を設け、ネジ部３４を通孔２４に貫通させ、ネジ部３４にナット３５を螺合させて薄板部３３で通孔２４を開閉するように構成してもよい。
【００４３】
また、通孔群２５の各通孔２４を開閉する薄板部３３の平面構成は、各通孔２４を開閉するような形状としても良いし、図８に示すように中央部に開口３３ａを有するリング状とし、この開口３３ａの径が異なる複数の薄板部３３を用意し、その中から選択して所定領域の通孔２４を開閉するようにしてもよい。なお、通孔２４を開閉する部材には、調整板２１を構成する材料と同質の材料を用いると良い。また、通孔２４を開閉する手段は上記例に限定されるものではなく、例えばめっきに害を及ぼさないような材料であれば、例えば可撓性を有する材料を通孔２４に埋め込んで開閉してもよいし、又はテープ状の薄板を通孔２４の開口部に貼り付けて開閉してもよい。
【００４４】
上記のようにしてめっきを行い、めっき終了後、めっき電源２８を被めっき基板Ｗ及びアノード１４から切り離し、基板ホルダ１２を被めっき基板Ｗごと引き上げて、被めっき基板Ｗの水洗及びリンスなどの必要な処理を行った後、めっき後の被めっき基板Ｗを次工程に搬送する。
【００４５】
図９乃至図１１は図３に示す調整板（通孔群２５の直径２８０ｍｍ）を用いて被めっき基板Ｗとして直径３００ｍｍの半導体ウエハ上にめっきを行った場合のバンプの分布状態を示す図で、図９は通孔群の分布調整を行わない場合、図１０は図５に示す遮蔽板３０を用いて通孔群の分布調整を行った場合、図１１は図６及び図７に示すように塊状の挿入部材又は薄板部で通孔を開閉し通孔群の分布調整を行った場合を示す。図９（ｂ）、図１０（ｂ）、図１１（ｂ）から明らかなように、通孔群の分布調整を行うことにより、めっき膜の膜厚をより均一にすることができる。なお、図では図９（ａ）、図１０（ａ）、図１１（ａ）に示すように被めっき基板ＷをＸ軸方向、Ｙ軸方向にＡ〜Ｅに分割してダンプ高さ（ダンプ厚さ）を測定している。
【００４６】
なお、調整板２１の構成は図３に限定されるものではなく、被めっき基板Ｗの形状が円形の場合は、図１２又は図１３に示すような構成のものでもよく、また、被めっき基板Ｗが矩形状である場合は、図１４又は図１５又は図１６に示すような構成でもよい。通孔２４の形状としては径寸法の同じ円形、又は径寸法の異なる円形とし、これらを組み合わせて通孔群を形成してもよい。
【００４７】
以上本発明の実施形態を説明したが、本発明は上記実施形態に限定されるものではなく、特許請求の範囲、及び明細書と図面に記載された技術的思想の範囲内において種々の変形が可能である。なお、直接明細書及び図面に記載がない何れの形状や構造や材質であっても、本願発明の作用・効果を奏する以上、本願発明の技術的思想の範囲内である。
【００４８】
【発明の効果】
以上説明したように各請求項に記載の発明によれば下記のような優れた効果が得られる。
【００４９】
請求項１に記載の発明によれば、調整板の通孔群の分布状態を調整することにより、この通孔内を電場が漏れ、漏れた電場が均一に拡がるように分布状態を調整することができ、被めっき体に形成される金属膜の面内均一性をより高めることができる。また、調整板の通孔群の分布状態を調整することにより、多数の通孔を通過するめっき液の流れを抑制し、このめっき液の流れにより影響を受けて、被めっき体に形成される金属膜の膜厚に不均一が生じることを防止することができる。また、被めっき体面内において、めっきのテストバンプの高さ分布の結果から、調整板上の通孔群の分布をそれに応じて自由に変え、バンプのより高い均一性が得られるように簡単に調整することができる。
【００５０】
請求項２に記載の発明によれば、通孔群分布調整手段を設けたことにより、請求項１に記載の発明と同様、被めっき体に形成される金属膜の面内均一性をより高めること、めっき液の流れにより影響を受けて被めっき体に形成される金属膜の膜厚に不均一が生じることを防止すること、めっきのテストバンプの高さ分布の結果からバンプのより高い均一性が得られるように簡単に調整することができる。また、これらは生産現場でめっき装置の実運転に先立って予め調整板の通孔群の分布状態を調整して行うことができ、被めっき体に均一な膜厚のめっき膜を形成することが容易になる。
【００５１】
請求項３に記載の発明によれば、調整板の通孔群を多数の通孔の組み合わせで形成するので、生産性を向上させることができる。また、孔開閉手段で通孔を開閉して通孔群の分布状態を調整するので、調整板を替えることなく、通孔群の分布状態の調整が可能となる。
【００５２】
請求項４に記載の発明によれば、孔開閉手段は薄板又は挿入材で孔を塞ぐように構成されているから、例えば半導体デバイスの生産ラインの実情を反映できる調整板によって通孔群の分布状態を調整し、めっき体面上に均一な膜厚の良好なめっき膜を形成できる。
【００５３】
請求項５に記載の発明によれば、液攪拌手段を設け、該めっき液攪拌手段でアノードと被めっき体との間のめっき液を攪拌することにより、十分な金属イオンを被めっき体に均一に供給でき、より均一な膜厚の金属めっき膜を形成することができる。また、めっき液攪拌手段として往復運動するパドル型攪拌機構を用いてめっき液を攪拌することにより、めっき液の流れに方向性をなくしながら十分な金属イオンを被めっき体に均一に供給することができる。
【図面の簡単な説明】
【図１】本発明に係るめっき装置の構成例を示す図である。
【図２】本発明に係るめっき装置の構成例を示す図である。
【図３】本発明に係るめっき装置の調整板の構成例を示す図である。
【図４】被めっき基板とその上に形成されるめっき膜の関係を示す図である。
【図５】本発明に係るめっき装置の遮蔽板の構成例を示す図である。
【図６】本発明に係るめっき装置の遮蔽板の通孔の開閉構成例を示す図である。
【図７】本発明に係るめっき装置の遮蔽板の通孔の開閉構成例を示す図である。
【図８】本発明に係るめっき装置の遮蔽板の構成例を示す図である。
【図９】本発明に係るめっき装置によるめっき膜の膜厚測定例を示す図である。
【図１０】本発明に係るめっき装置によるめっき膜の膜厚測定例を示す図である。
【図１１】本発明に係るめっき装置によるめっき膜の膜厚測定例を示す図である。
【図１２】本発明に係るめっき装置の調整板の構成例を示す図である。
【図１３】本発明に係るめっき装置の調整板の構成例を示す図である。
【図１４】本発明に係るめっき装置の調整板の構成例を示す図である。
【図１５】本発明に係るめっき装置の調整板の構成例を示す図である。
【図１６】本発明に係るめっき装置の調整板の構成例を示す図である。
【図１７】従来のめっき装置の構成例を示す図である。
【図１８】従来のめっき装置の構成例を示す図である。
【図１９】従来のめっき装置の調整板の構成例を示す図である。
【図２０】被めっき基板とその上に形成されるめっき膜の関係を示す図である。
【符号の説明】
１０めっき液
１１めっき槽
１２基板ホルダ
１３アノードホルダ
１４アノード
１５溢流堰
１６オーバーフロー槽
１７循環配管
１８循環ポンプ
１９恒温ユニット
２０フィルタ
２１調整板
２２パドル
２３攪拌機構
２４通孔
２５通孔群
２６導線
２７導線
２８めっき電源
３０遮蔽板
３１レバー
３２挿入部材
３３薄板部
３４ネジ部
３５ナット[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plating apparatus for plating a surface of a substrate to be plated such as a semiconductor wafer, and in particular, to form a plating film in fine wiring grooves and holes provided on the surface of a semiconductor wafer, a resist opening, or to form a plating film on a semiconductor wafer. The present invention relates to a plating method and a plating apparatus suitable for forming a bump (protruding electrode) electrically connected to a package electrode or the like on the surface.
[0002]
[Prior art]
For example, in a TAB (Tape Automated Bonding) or a flip chip, gold, copper, solder, nickel, or a protruding connection electrode obtained by laminating these at a predetermined position (electrode) on the surface of a semiconductor chip on which wiring is formed. (Bumps) are widely formed and electrically connected to electrodes of a package or TAB electrodes via the bumps. There are various methods for forming the bump, such as an electroplating method, an evaporation method, a printing method, and a ball bump method. However, an electroplating method which is relatively stable is often used.
[0003]
According to the electroplating method, a high-purity metal film (plating film) can be easily obtained, and not only the deposition rate of the metal film is relatively high, but also the thickness of the metal film can be controlled relatively easily. Can be. In forming a metal film on a semiconductor wafer, not only the film thickness but also the uniformity of the film thickness within the semiconductor wafer surface is strictly required in order to pursue high-density mounting, high performance, and high yield. . Regarding the film thickness distribution of the electroplating, it has been expected that an excellent uniform film can be obtained by making the metal ion supply rate distribution and the potential distribution of the plating solution uniform.
[0004]
FIG. 17 is a diagram showing an example of the configuration of a conventional plating apparatus employing a so-called face-down method. This plating apparatus detachably holds a plating tank 111 having a plating solution 110 therein and an open top, and a substrate W to be plated such as a semiconductor wafer with its surface (plated surface) facing down (face down). And a vertically movable substrate holder 112. An anode 113 is horizontally arranged at the bottom of the plating tank 111, an overflow tank 114 is provided around the upper part, and a plating solution supply nozzle 115 is provided at the bottom of the plating tank 111.
[0005]
The substrate W to be plated, which is horizontally held by the substrate holder 112, is disposed at a position where the upper end opening of the plating bath 111 is closed, and in this state, the plating solution 110 is supplied from the plating solution supply nozzle 115 into the plating bath 111. By overflowing the plating solution 110 from above the plating tank 111, the plating solution 110 is brought into contact with the surface of the substrate W to be plated held by the substrate holder 112, and at the same time, the anode 113 is connected to the plating power source 118 through the conductive wire 116. , The substrate W to be plated is connected to the cathode of the plating power supply 118 via the conductive wire 117, and a predetermined plating voltage is applied between the substrate W to be plated and the anode 113. Thus, due to the potential difference between the substrate W to be plated and the anode 113, metal ions in the plating solution 110 receive electrons from the surface of the substrate W to be plated, and the metal is deposited on the surface of the substrate W to be plated to form a metal film. You.
[0006]
According to the plating apparatus having the above configuration, the size of the anode 113, the distance between the electrodes and the potential difference between the anode 113 and the substrate W to be plated, and the supply speed of the plating solution 110 supplied from the plating solution supply nozzle 115 are adjusted. Thereby, the uniformity of the thickness of the metal film formed on the surface of the substrate W to be plated can be adjusted to some extent.
[0007]
FIG. 18 is a diagram showing an example of a configuration of a conventional plating apparatus employing a so-called dip method. This plating apparatus has a plating tank 120 having a plating solution therein, and a substrate W to be plated, which is held in the plating tank 120 by sealing a peripheral portion of the substrate holder 121 in a watertight manner, and an anode holder 124. The held anodes 122 are vertically arranged facing each other. An adjustment plate (regulation plate) 123 made of a dielectric and having a center hole 123a formed in the center is disposed between the anode 122 and the substrate W to be plated.
[0008]
The plating solution is accommodated in the plating tank 120, and the anode 122, the substrate W to be plated, and the adjustment plate 123 are immersed in the plating solution. At the same time, the anode 122 is connected to the anode of the plating power supply 127 via the conductor 125, and the conductor 126 is connected. The substrate W to be plated is connected to the cathode of the plating power supply 127 via a, and a predetermined plating voltage is applied between the anode 122 and the substrate W to be plated, so that the surface of the substrate W The metal is deposited to form a metal film.
[0009]
According to the plating apparatus having the above-described configuration, the adjustment plate 123 having the center hole 123a is disposed between the anode 122 and the substrate W to be plated disposed at a position facing the anode 122. By adjusting the potential distribution in the plating tank 120, the thickness distribution of the metal film formed on the surface of the substrate W to be plated can be adjusted to some extent.
[0010]
FIG. 19 is a diagram showing another configuration example of a conventional plating apparatus employing a so-called dip method. This plating apparatus differs from the plating apparatus shown in FIG. 18 in that a ring-shaped pseudo-cathode 130 is provided without an adjustment plate 123 between the anode 122 and the substrate W to be plated. In the state where the pseudo cathode 130 is arranged, the substrate W to be plated is held in the substrate holder 121, and the pseudo cathode 130 is connected to the cathode of the plating power supply 127 via the conducting wire 131 during the plating process. is there. According to this plating apparatus, the uniformity of the thickness of the metal film formed on the surface of the substrate W to be plated can be improved by adjusting the potential of the pseudo cathode 130. Note that, in FIG. 19, portions denoted by the same reference numerals as those in FIG. 18 indicate the same or corresponding portions.
[0011]
For example, if the semiconductor wafer is described as the substrate to be plated W, when forming a metal film (plating film) for wiring or bumps on the surface of the substrate to be plated, the thickness of the metal film over the entire surface of the substrate to be plated W However, it is quite difficult to form a metal film that satisfies such requirements in the conventional plating apparatus. For example, when plating is performed on the substrate W to be plated by the plating apparatus having the configuration shown in FIG. 17, a metal film strongly affected by the flow of the plating solution 110 is formed. As shown in a), there is a tendency that the thickness of the metal film P is thicker in the central portion of the substrate W to be supplied with sufficient metal ions than in the peripheral portion. If the flow of the plating solution 110 is made very slow to prevent this, the metal film P tends to be thicker at the peripheral edge of the substrate W to be plated than at the center, as shown in FIG. Occurs.
[0012]
Further, when plating is performed on the substrate W to be plated by the plating apparatus shown in FIG. 18, the potential distribution is improved by the adjustment plate 123 having the central hole 123a at the center, and the thickness of the metal film over the entire surface of the substrate W to be plated is improved. Although the uniformity of the distribution can be improved to some extent, as shown in FIG. 20C, the thickness of the metal film P is increased in the central portion and the peripheral portion of the substrate W to be plated. That is, there is a tendency that a metal film P having a wavy film thickness distribution is formed.
[0013]
In addition, it is common in production sites that the thickness of the metal film P is significantly different between the upper and lower or left and right regions of the substrate W to be plated. The tendency to form a metal film P having a film thickness distribution like a polarized wave is often seen. Further, when plating is performed by the plating apparatus shown in FIG. 19, it is not only difficult to adjust the voltage of the pseudo electrode 130, but also it is necessary to remove the metal film attached to the surface of the pseudo electrode 130. Is rather complicated.
[0014]
The conventional plating apparatus has different plating film thickness distributions due to the characteristics of each configuration, and it has been difficult to obtain a good and uniform plating film. The first reason is that the plating tank is made as small as possible by the integration of the apparatus, and there is an electric field non-uniformity due to an electric field boundary effect in the tank. The non-uniformity can be mitigated to some extent using an adjustment plate, but a fixing mechanism such as a substrate holder that holds the substrate to be plated in the plating tank, a stirring mechanism for the plating solution, and a conductive contact of the substrate to be plated as a cathode The nonuniformity of the electric field caused by various factors such as the situation, the resistance of the base of the substrate to be plated, the opening area of the substrate to be plated, and the distribution of the pattern is various.
[0015]
Secondly, it is considered that the metal ion distribution of the electrolyte flowing in each hole tends to be non-uniform in the holes of the deep resist pattern on the surface of the substrate to be plated as the cathode. The stirring causes a large number of eddies in the tank space where the flow of the electrolyte in the tank is limited, and the non-uniformity of the plating solution in the tank is improved. It can be seen that the distribution of metal ions is still non-uniform depending on the resist material, pattern shape, plating conditions, eddy current size and distribution. In other words, the uniform distribution of the metal ions depends not only on the distribution of the electric field intensity between the two electrodes, but also on the resist pattern and the stirring conditions.
[0016]
In the production line, despite the fact that various influencing factors fluctuate depending on the conditions, the conventional plating equipment takes measures using a fixed one such as an adjustment plate or a pseudo cathode having almost symmetry. However, it has been difficult to cope with a change in the production situation, which tends to diversify the substrates to be plated. In addition, a long time or a high cost is required from the analysis of the production situation to the completion of the remodeling of the apparatus and the process tuning.
[0017]
In the semiconductor device manufacturing industry, the evaluation of the film thickness uniformity β of the plating film on the semiconductor wafer surface is as follows.
β = (T _max -T _min ) / (T _max + T _min (1)
Where T _max Is the maximum thickness of the plating film, T _min Is the minimum thickness of the plating film. Since it is common to use equation (1), the uniformity of the semiconductor wafer surface is greatly affected by individual abnormal values. Based on a symmetrical adjustment plate or the like, specific local and asymmetric countermeasures are required according to the process tuning of semiconductor wafer production.
[0018]
[Patent Document 1]
JP-A-11-152600
[Patent Document 2]
JP-A-11-193497
[0019]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a low-cost and complicated operation method capable of freely and finely adjusting a potential distribution applied when plating on a substrate to be plated such as a semiconductor wafer. An object of the present invention is to provide a plating method and a plating apparatus that can form a plating film having a uniform thickness on a surface of a substrate to be plated without necessity.
[0020]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention according to claim 1 immerses the plating solution in a plating tank holding a plating solution, arranges the anode and the object to be opposed to each other, and sets the anode and the object to be plated together. In a plating method in which an adjustment plate is disposed between the anode and the object to be plated, a current is applied between the anode and the object to be plated, and the plating is performed on the object to be plated. It has a through-hole group consisting of a large number of through-holes penetrating on the side surface, adjusts the distribution state of the through-hole group of the adjustment plate, adjusts the electric field distribution between the anode and the object to be plated, and forms a plating film on the object to be plated. It is characterized in that the thickness is adjusted.
[0021]
By adjusting the distribution state of the through-hole group of the adjusting plate, the electric field leaks through the through-holes, and the distribution state can be adjusted so that the leaked electric field spreads uniformly, and is formed on the body to be plated. The in-plane uniformity of the metal film can be further improved. Further, by adjusting the distribution state of the through-hole group of the adjusting plate, the flow of the plating solution passing through the large number of through-holes is suppressed, and is affected by the flow of the plating solution to be formed on the body to be plated. Nonuniformity in the thickness of the metal film can be prevented. In addition, the distribution of the through holes on the adjustment plate can be freely changed in accordance with the height distribution of the test bumps in the plating target surface within the surface of the plating object, so that a higher uniformity of the bumps can be obtained. Can be adjusted.
[0022]
According to a second aspect of the present invention, the anode and the object to be plated are arranged so as to face each other by being immersed in the plating solution of the plating tank holding the plating solution, and an adjusting plate is arranged between the anode and the object to be plated. Then, in a plating apparatus in which a current is applied between the anode and the object to be plated to perform plating on the object to be plated, the adjustment plate is made of a dielectric material, and is made up of a large number of through holes penetrating from the side of the object to be plated to the side of the anode. It is characterized by having a through-hole group and providing a through-hole group distribution adjusting means for adjusting the distribution state of the through-hole group of the adjusting plate.
[0023]
By providing the through-hole group distribution adjusting means as described above, the in-plane uniformity of the metal film formed on the object to be plated can be further enhanced, as in the first aspect of the present invention. Prevents non-uniformity of the thickness of the metal film formed on the plating object due to the influence, and is simple so that higher bump uniformity can be obtained from the test bump height distribution result of plating. Can be adjusted. In addition, these can be performed by adjusting the distribution state of the through-hole group of the adjusting plate in advance of the actual operation of the plating apparatus at the production site, so that a plating film having a uniform thickness can be formed on the body to be plated. Become easy.
[0024]
According to a third aspect of the present invention, in the plating apparatus according to the second aspect, the through hole group distribution adjusting means includes a hole opening and closing means for opening and closing the through holes of the through hole group, and the through hole group is controlled by the hole opening and closing means. It is a means for adjusting the distribution state of.
[0025]
As described above, since the through-hole group of the adjusting plate is formed by combining a large number of through-holes, productivity can be improved. In this case, the diameter of the pore is generally 1 to 60 mm, preferably about 2 to 10 mm. The space between the pores is generally between 2 and 50 mm, preferably between 2 and 10 mm. In addition, since the through holes are opened and closed by the hole opening and closing means to adjust the distribution state of the through hole groups, the distribution state of the through hole groups can be adjusted without changing the adjustment plate.
[0026]
According to a fourth aspect of the present invention, in the plating apparatus according to the third aspect, the hole opening / closing means is configured to close the hole with a thin plate or an insert.
[0027]
Since the hole opening / closing means is configured to close the hole with a thin plate or an insert as described above, the distribution state of the through hole group is adjusted by an adjustment plate that can reflect the actual situation of the production line of the semiconductor device, and the surface of the plated body is adjusted. A good plating film having a uniform thickness can be formed thereon.
[0028]
According to a fifth aspect of the present invention, in the plating apparatus according to any one of the second to fourth aspects, a plating solution stirring means for stirring a plating solution between the anode and the body to be plated is provided. And
[0029]
By providing the plating solution stirring means as described above, and by stirring the plating solution between the anode and the object to be plated by the plating solution stirring means, sufficient metal ions can be uniformly supplied to the object to be plated, and more uniform A metal plating film having an appropriate thickness can be formed. Further, by stirring the plating solution using a reciprocating paddle-type stirring mechanism as a plating solution stirring means, sufficient metal ions can be uniformly supplied to the object to be plated while the flow of the plating solution has no directivity. it can.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are views showing a configuration of a plating apparatus according to the present invention. As shown in FIGS. 1 and 2, the present plating apparatus includes a plating tank 11 for holding a plating solution 10 therein, in which a substrate W to be plated mounted on a substrate holder 12 and an anode holder An anode 14 mounted on 13 is arranged to face. The substrate W to be plated has a disk shape, the periphery thereof is sealed in a water-tight manner, and the surface (plated surface) is exposed, and is held detachably on the substrate holder 12. The substrate holder 12 is vertically movable.
[0031]
On both sides of the plating tank 11, there are provided overflow tanks 16 for flowing the plating solution 10 overflowing the upper end of the overflow weir 15 of the plating tank 11. The overflow tank 16 and the plating tank 11 are connected by a circulation pipe 17. Have been. A circulation pump 18, a constant temperature unit 19 and a filter 20 are connected to the circulation pipe 17 in series. The plating solution 10 supplied into the plating tank 11 by driving the circulation pump 18 fills the inside of the plating tank 11, and then overflows from the overflow weir 15, flows into the overflow tank 16, and returns to the circulation pump 18. It is configured to circulate.
[0032]
The shape of the anode 14 is circular along the shape of the substrate W to be plated, and the anode 14 and the substrate W to be plated are immersed in the plating solution 10 when the plating bath 11 is filled with the plating solution 10. It has become. Further, the plating bath 11 is partitioned between the anode 14 and the substrate holder 12 to partition the inside of the plating bath 11 into an anode side chamber 11a and a substrate side chamber 11b to be plated. An adjustment plate 21 for shutting off is provided on the plating substrate side.
[0033]
A plurality of paddles 22 are provided between the substrate holder 12 and the adjustment plate 21 and are suspended downward. The paddles 22 are positioned inside the plating solution 10 in the substrate side chamber 11b to be plated and held by the substrate holder 12. An agitating mechanism 23 for agitating the plating solution 10 in the substrate side chamber 11b by reciprocating in parallel with the substrate W to be plated is provided.
[0034]
The adjusting plate 21 has a thickness of, for example, about 0.5 to 10 mm and is made of a dielectric material made of PVC, PP, PEEK, PES, HT-PVC, PFA, PTFE, or another resin material. Then, when a predetermined region inside the adjustment plate 21, that is, the substrate W to be plated is held at the substrate holder 12 and is arranged at a predetermined plating position in the plating bath 11, the substrate W faces the surface of the substrate W to be plated. A through-hole group 25 including a large number of through-holes 24 is provided over substantially the entire region and in a circular region similar to the substrate W to be plated.
[0035]
As shown in detail in FIG. 3, the adjusting plate 21 has a configuration in which the through-hole group 25 is formed by uniformly distributing thin slit-shaped through-holes (pores) 24 in a circular region. The diameter of the through holes 24 is set to 2 mm in this example, and here, a total of 633 holes are provided. The diameter of the through hole 24 is generally set arbitrarily in the range of 1 to 60 mm, but is preferably about 2 to 10 mm.
[0036]
As described above, a through-hole group 25 including a large number of through-holes 24 is provided inside the adjustment plate 21, and when plating is performed, an electric field is formed through each of the through-holes 24, and the formed electric field is By making it spread evenly, the potential distribution over the entire surface (plated surface) of the substrate W to be plated is made more uniform, and the in-plane uniformity of the metal film formed on the surface of the substrate W to be plated is improved. Can be more enhanced. In addition, by suppressing the plating solution 10 from passing through a large number of through holes 24 provided inside the adjusting plate 21 installed in the plating tank 11, the flow of the plating solution 10 (return of the plating solution) is reduced. Under the influence, it is possible to prevent the film thickness of the metal film formed on the surface of the substrate to be plated W from becoming uneven.
[0037]
In particular, leakage of the electric field can be promoted while suppressing the flow of the plating solution 10 in the through holes 24. Further, a through-hole group 25 including a large number of through-holes 24 is formed in substantially the entire region of the adjustment plate 21 facing the surface of the substrate W to be plated and in a circular region similar to the substrate W to be plated. Thus, it is possible to form a metal film having good film thickness uniformity in all directions on the surface of the substrate W to be plated.
[0038]
According to this example, first, the plating bath 10 is filled with the plating bath 10 and the plating bath 10 is circulated as described above. In this state, the substrate holder 12 holding the substrate W to be plated is lowered, and the substrate W to be plated is placed at a predetermined position in the plating bath 11 immersed in the plating solution 10. In this state, the anode 14 is connected to the anode of the plating power supply 28 via the conducting wire 26, and the substrate W to be plated is connected to the cathode of the plating power supply 28 via the conducting wire 27, and at the same time, the stirring mechanism 23 is driven to drive the paddle 22. By reciprocating along the surface of the substrate W to be plated, the plating solution 10 in the substrate-side chamber 11b is agitated, whereby the metal is deposited on the surface of the substrate W to be plated to form a metal film.
[0039]
At this time, as described above, the electric field leaks through the large number of through holes 24 provided inside the adjustment plate 21 and the leaked electric field is uniformly spread, so that the surface of the substrate W to be plated (the surface to be plated) is formed. 4), the potential distribution over the entire surface can be made more uniform, and as shown in FIG. 4, a metal film P with improved in-plane uniformity can be formed on the surface of the substrate W to be plated. Moreover, by agitating the plating solution 10 between the substrate W to be plated and the adjusting plate 21 by the paddle 22 during the plating process, sufficient metal ions can be removed from the plating solution And a metal film having a more uniform film thickness can be formed more quickly.
[0040]
Here, a shielding plate 30 having the configuration shown in FIG. 5 is arranged so as to overlap the adjusting plate 21. The shielding plate 30 has a mechanism like a diaphragm of a camera, and the diameter of the central opening 30a is enlarged or reduced by operating the lever 31 as shown by arrows A and B. The shielding plate 30 is arranged so that its central opening 30a is concentric with the circular region where the through-hole group 25 of the adjusting plate 21 is provided. Thus, the distribution state of the through hole group (the area of the through hole group) can be adjusted by operating the lever 31.
[0041]
By adjusting the distribution state of the through-hole group 25 as described above, the electric field leaks through the through-hole 24, and the distribution state can be adjusted so that the leaked electric field spreads evenly. The in-plane uniformity of the formed metal film can be further improved. Further, by adjusting the distribution state of the through-hole group 25 of the adjusting plate 21, the flow of the plating solution passing through the large number of through-holes 24 is suppressed. It is possible to prevent non-uniformity in the thickness of the metal film formed on the substrate. In addition, in the surface of the substrate W to be plated, the distribution of the through holes 25 on the adjustment plate 21 can be freely changed according to the result of the height distribution of the test bumps for plating, and higher uniformity of the bumps can be obtained. Can be adjusted as follows.
[0042]
In the above example, the distribution state of the through-hole group 25 is adjusted by using a shielding plate 30 having a mechanism such as a diaphragm of a camera, and adjusting the diameter of the central opening 30a to open and close the through-hole group 25. Although the amount of the through-holes 24 is changed, the adjustment of the distribution state of the through-hole group 25 is not limited to this, and as shown in the sectional configuration of FIG. You may comprise by inserting or removing the member 32. As shown in FIG. 7, a screw portion 34 is provided in the thin plate portion 33 to penetrate the through hole 24, the screw portion 34 is penetrated through the through hole 24, and a nut 35 is screwed into the screw portion 34 to form the thin plate portion 33. May be configured to open and close the through hole 24.
[0043]
Further, the planar configuration of the thin plate portion 33 that opens and closes each through hole 24 of the through hole group 25 may be a shape that opens and closes each through hole 24, and has an opening 33a at the center as shown in FIG. A plurality of thin plate portions 33 having a ring shape and different diameters of the openings 33a may be prepared, and the thin plate portions 33 may be selected from the thin plate portions 33 to open and close the through holes 24 in a predetermined region. Note that a material that is the same as the material forming the adjustment plate 21 is preferably used for the member that opens and closes the through hole 24. The means for opening and closing the through hole 24 is not limited to the above example. For example, any material that does not harm plating can be opened and closed by embedding a flexible material into the through hole 24. Alternatively, a tape-shaped thin plate may be attached to the opening of the through hole 24 to open and close.
[0044]
Plating is performed as described above, and after plating is completed, the plating power source 28 is separated from the substrate W to be plated and the anode 14, and the substrate holder 12 is pulled up together with the substrate W to be plated, and it is necessary to wash and rinse the substrate W to be plated. After performing the various processes, the substrate W to be plated is transported to the next step.
[0045]
FIGS. 9 to 11 are diagrams showing distribution states of bumps when plating is performed on a semiconductor wafer having a diameter of 300 mm as a substrate to be plated W using the adjustment plate (the diameter of the through hole group 25 is 280 mm) shown in FIG. 9 shows the case where the distribution adjustment of the through-hole group is not performed, FIG. 10 shows the case where the distribution adjustment of the through-hole group is performed using the shielding plate 30 shown in FIG. 5, and FIG. Fig. 7 shows a case where the through holes are opened and closed by a massive insertion member or a thin plate portion to adjust the distribution of the through holes. As is clear from FIGS. 9 (b), 10 (b), and 11 (b), by adjusting the distribution of the through-hole groups, the thickness of the plating film can be made more uniform. 9A, FIG. 10A, and FIG. 11A, the substrate W to be plated is divided into A to E in the X-axis direction and the Y-axis direction to divide the substrate W into a dump height (dump height). Thickness).
[0046]
The configuration of the adjustment plate 21 is not limited to that shown in FIG. 3. When the substrate W to be plated has a circular shape, the configuration shown in FIG. 12 or FIG. 13 may be used. When W is rectangular, a configuration as shown in FIG. 14, FIG. 15, or FIG. 16 may be used. The shape of the through holes 24 may be a circle having the same diameter or a circle having a different diameter, and these may be combined to form a group of through holes.
[0047]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications may be made within the scope of the claims and the technical idea described in the specification and the drawings. It is possible. It should be noted that any shape, structure, or material that is not directly described in the specification and drawings is within the scope of the technical idea of the present invention as long as the effects and effects of the present invention are exhibited.
[0048]
【The invention's effect】
As described above, according to the invention described in each claim, the following excellent effects can be obtained.
[0049]
According to the first aspect of the present invention, by adjusting the distribution state of the through-hole group of the adjusting plate, the electric field leaks in the through-hole, and the distribution state is adjusted so that the leaked electric field is spread evenly. Thus, the in-plane uniformity of the metal film formed on the body to be plated can be further improved. Further, by adjusting the distribution state of the through-hole group of the adjusting plate, the flow of the plating solution passing through the large number of through-holes is suppressed, and is affected by the flow of the plating solution to be formed on the body to be plated. Nonuniformity in the thickness of the metal film can be prevented. In addition, the distribution of the through holes on the adjustment plate can be freely changed according to the height distribution of the test bumps in the plating target surface within the surface of the plating target, so that higher uniformity of the bumps can be obtained. Can be adjusted.
[0050]
According to the second aspect of the present invention, the provision of the through-hole group distribution adjusting means further enhances the in-plane uniformity of the metal film formed on the object to be plated, similarly to the first aspect of the present invention. To prevent unevenness in the thickness of the metal film formed on the object to be plated affected by the flow of the plating solution, and to achieve a higher uniformity of the bumps from the results of the height distribution of the test bumps in the plating. It can be easily adjusted to achieve the desired performance. In addition, these can be performed by adjusting the distribution state of the through-hole groups of the adjusting plate in advance of the actual operation of the plating apparatus at the production site, so that a plated film having a uniform thickness can be formed on the body to be plated. Become easy.
[0051]
According to the third aspect of the present invention, since the through-hole group of the adjusting plate is formed by a combination of a large number of through-holes, productivity can be improved. In addition, since the through holes are opened and closed by the hole opening and closing means to adjust the distribution state of the through hole groups, the distribution state of the through hole groups can be adjusted without changing the adjustment plate.
[0052]
According to the fourth aspect of the present invention, the hole opening / closing means is configured to close the hole with a thin plate or an insert material. By adjusting the state, a good plating film having a uniform thickness can be formed on the plating body surface.
[0053]
According to the fifth aspect of the present invention, by providing the solution stirring means and stirring the plating solution between the anode and the object to be plated by the plating solution stirring means, sufficient metal ions can be uniformly distributed on the object to be plated. And a metal plating film having a more uniform film thickness can be formed. Further, by stirring the plating solution using a reciprocating paddle-type stirring mechanism as a plating solution stirring means, sufficient metal ions can be uniformly supplied to the object to be plated while the flow of the plating solution has no directivity. it can.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of a plating apparatus according to the present invention.
FIG. 2 is a diagram showing a configuration example of a plating apparatus according to the present invention.
FIG. 3 is a diagram showing a configuration example of an adjustment plate of the plating apparatus according to the present invention.
FIG. 4 is a diagram showing a relationship between a substrate to be plated and a plating film formed thereon.
FIG. 5 is a diagram showing a configuration example of a shielding plate of the plating apparatus according to the present invention.
FIG. 6 is a view showing a configuration example of opening and closing of a through hole of a shielding plate of the plating apparatus according to the present invention.
FIG. 7 is a view showing a configuration example of opening and closing of a through hole of a shielding plate of the plating apparatus according to the present invention.
FIG. 8 is a diagram showing a configuration example of a shielding plate of the plating apparatus according to the present invention.
FIG. 9 is a view showing an example of measuring a film thickness of a plating film by the plating apparatus according to the present invention.
FIG. 10 is a view showing an example of measuring the thickness of a plating film by the plating apparatus according to the present invention.
FIG. 11 is a view showing an example of measuring the thickness of a plating film by the plating apparatus according to the present invention.
FIG. 12 is a diagram showing a configuration example of an adjustment plate of the plating apparatus according to the present invention.
FIG. 13 is a diagram showing a configuration example of an adjustment plate of the plating apparatus according to the present invention.
FIG. 14 is a diagram showing a configuration example of an adjustment plate of the plating apparatus according to the present invention.
FIG. 15 is a diagram showing a configuration example of an adjustment plate of the plating apparatus according to the present invention.
FIG. 16 is a diagram showing a configuration example of an adjustment plate of the plating apparatus according to the present invention.
FIG. 17 is a diagram showing a configuration example of a conventional plating apparatus.
FIG. 18 is a diagram showing a configuration example of a conventional plating apparatus.
FIG. 19 is a diagram illustrating a configuration example of an adjustment plate of a conventional plating apparatus.
FIG. 20 is a diagram showing a relationship between a substrate to be plated and a plating film formed thereon.
[Explanation of symbols]
10 Plating solution
11 Plating tank
12 Substrate holder
13 Anode holder
14 Anode
15 Overflow Weir
16 overflow tank
17 Circulation piping
18 Circulation pump
19 Constant temperature unit
20 Filter
21 Adjustment plate
22 paddles
23 Stirring mechanism
24 through holes
25 through-hole group
26 conductors
27 conductor
28 Plating power supply
30 Shield plate
31 lever
32 Insertion member
33 Thin plate
34 Screw
35 nut

Claims

The anode and the object to be plated are immersed in the plating solution of the plating tank holding the plating solution, and the anode and the object to be plated are arranged to face each other, and an adjusting plate is arranged between the anode and the object to be plated. And a plating method in which plating is performed on a body to be plated by energizing between
The adjusting plate is made of a dielectric material, and the adjusting plate has a through-hole group including a large number of through-holes penetrating from the side surface of the body to be plated to the side surface of the anode,
A plating method, comprising: adjusting a distribution state of a group of through-holes of the adjusting plate; adjusting an electric field distribution between the anode and the object to be plated; and adjusting a plating film thickness of the object to be plated.

The anode and the object to be plated are immersed in the plating solution of the plating tank holding the plating solution, and the anode and the object to be plated are arranged to face each other, and an adjusting plate is arranged between the anode and the object to be plated. And a plating apparatus that performs plating on the body to be plated by energizing between
The adjusting plate is made of a dielectric material, and has a through-hole group including a large number of through-holes penetrating from the side surface of the body to be plated to the side surface of the anode,
A plating apparatus comprising a through-hole group distribution adjusting means for adjusting a distribution state of through-hole groups of the adjusting plate.

The plating apparatus according to claim 2,
The plating apparatus, characterized in that the through-hole group distribution adjusting means has a hole opening / closing means for opening / closing the through-holes of the through-hole group, and is a means for adjusting the distribution state of the through-hole groups by the hole opening / closing means.

The plating apparatus according to claim 3,
The plating apparatus, wherein the hole opening / closing means is configured to close the hole with a thin plate or an insert.

The plating apparatus according to any one of claims 2 to 4, further comprising a plating solution stirring means for stirring a plating solution between the anode and the body to be plated.