JP4010791B2

JP4010791B2 - Electroless plating apparatus and electroless plating method

Info

Publication number: JP4010791B2
Application number: JP2001319837A
Authority: JP
Inventors: 明久本郷; 新明王; 尚起松田
Original assignee: Ebara Corp
Current assignee: Ebara Corp
Priority date: 2001-08-10
Filing date: 2001-10-17
Publication date: 2007-11-21
Anticipated expiration: 2021-10-17
Also published as: JP2003129250A

Description

【０００１】
【発明の属する技術分野】
本発明は、無電解めっき装置及び無電解めっき方法に関し、特に半導体基板等の基板の表面に設けた配線用の微細な凹部に、銅や銀等の導電体を埋め込んで埋め込み配線を形成したり、このようにして形成した配線の表面を保護する保護膜を形成したりするのに使用される無電解めっき装置及び無電解めっき方法に関する。
【０００２】
【従来の技術】
無電解めっきは、外部から電気を流すことなく、めっき液中の金属イオンを化学的に還元して被処理材の被めっき面にめっき膜を形成するようにした方法であり、耐食、耐摩耗性のニッケル−りん，ニッケル−硼素めっき、プリント配線基板用銅めっきなどに広く用いられている。
【０００３】
この無電解めっき装置としては、無電解めっき液をオーバーフローさせつつ保持するめっき処理槽と、このめっき処理槽の上部に配置され、基板等の被処理材を横向きに保持する上下動自在な保持部とを有し、この保持部で保持した被処理材をめっき処理槽内のめっき液に浸漬（いわゆるどぶ漬け）させるようにしたものや、基板等の被処理材を上向き（フェースアップ）に保持する保持部と、この保持部で保持した被処理材の上面（被めっき面）に無電解めっき液を供給するめっき液供給部とを有し、この保持部で保持した被処理材の上面に沿って無電解めっき液を流すようにしたもの等が一般に知られている。
【０００４】
近年、半導体チップの高速化、高集積化に伴い、半導体基板上に配線回路を形成するための金属材料として、アルミニウムまたはアルミニウム合金に代えて、電気抵抗率が低くエレクトロマイグレーション耐性が高い銅（Ｃｕ）を用いる動きが顕著になっている。この種の銅配線は、基板の表面に設けた微細凹みの内部に銅を埋込むことによって一般に形成される。この銅配線を形成する方法としては、ＣＶＤ、スパッタリング及びめっきといった手法があるが、めっきが一般的である。いずれにしても、基板の表面に銅層を成膜した後、その表面を化学的機械的研磨（ＣＭＰ）により平坦に研磨するようにしている。
【０００５】
この種の配線にあっては、平坦化後、その配線の表面が外部に露出しており、この上に埋め込み配線を形成する際、例えば次工程の層間絶縁膜形成プロセスにおけるＳｉＯ_２形成時の表面酸化やコンタクトホールを形成するためのＳｉＯ_２エッチング等に際して、コンタクトホールの底に露出した配線のエッチャントやレジスト剥離等による表面汚染、更には銅配線にあっては銅の拡散が懸念されている。
【０００６】
このため、銀や銅等の配線材料との接合が強く、しかも比抵抗（ρ）が低い、例えばＮｉ−Ｂ合金膜等からなる保護膜（めっき膜）で配線の表面を選択的に覆って保護することが考えられる。ここで、Ｎｉ−Ｂ合金膜は、例えばニッケルイオン、ニッケルイオンの錯化剤、ニッケルイオンの還元剤としてのアルキルアミンボランまたは硼素化水素化合物等を有する無電解めっき液を使用した無電解めっきを施すことによって、銅等の表面に選択的に形成することができる。
【０００７】
【発明が解決しようとする課題】
無電解めっきの適用箇所は、銅配線の主たる埋め込み材（Ｃｕ）、バリヤメタル上のシード層の形成、またはシードの補強（Ｃｕ）、さらにはバリヤメタルそのものの形成、銅配線材の蓋材形成（いずれもＮｉ−Ｐ，Ｎｉ−Ｂ，Ｃｏ−Ｐ，Ｎｉ−Ｗ−Ｐ，Ｎｉ−Ｃｏ−Ｐ，Ｃｏ−Ｗ−Ｐ，Ｃｏ−Ｗ−Ｂ）などがあるが、いずれの無電解めっきプロセスでも被処理材の全面に亘る膜厚の均一性が要求される。
【０００８】
ここで、無電解めっきにあっては、被処理材が無電解めっき液と接触すると同時に被めっき面にめっき金属が析出し、めっき液の温度によってめっき金属の析出速度が異なる。このため、被処理材の被めっき面に均一な膜厚のめっき膜を形成するためには、めっき液が被処理材と接触した当初から被めっき面の面内全域におけるめっき液の温度が均一で、接触中の全めっき処理中に亘ってこの温度を一定に保持することが要求される。
【０００９】
しかしながら、従来の無電解めっき装置は、一般にヒータを内蔵した保持部の上面または下面に基板等の被処理材を密着させて保持し、ヒータを介して被処理材を加熱した状態で、被処理材の被めっき面に所定の温度に加熱した無電解めっき液を接触させるようにしていた。このため、被処理材の凹凸や保持部の面粗度等の影響で、被処理材と保持部との間に空気溜まりが発生して、この空気溜まりが断熱材として作用する等、共に固体である被処理材と保持部との間の熱伝導に大きなばらつきが生じ、しかも、保持部の表面には、一般に熱伝導率の悪いテフロン（商標名）等のシートが貼着されているため、被処理材の全面における温度が一様にならず、温度均一性に問題があった。
【００１０】
つまり、無電解めっきのレートや膜質は、無電解めっき液の温度に依存するところが大きく、被処理材の全面に亘る膜厚の均一性を確保するためには、めっき液の温度を被処理材の全面に亘って±１℃の範囲でコントロールすることが望まれるが、従来の無電解めっき装置にあっては、めっき中に被処理材に接触するめっき液に±５℃程度の温度のばらつきが生じて、この要求に応えることが困難であった。更に、保持部からの熱の逃げや、めっき液表面からの熱の逃げも被処理材の外周部の温度を低下させる要因になっていた。このように、被処理材の全面における温度が一様にならず、温度均一性に問題があることは、電解めっき装置にあっても同様であった。
【００１１】
本発明は上記に鑑みてなされたもので、被処理材の被めっき面により均一なめっき膜を容易に形成できるようにした無電解めっき装置及び無電解めっき方法を提供することを目的とする。
【００１２】
【課題を解決するための手段】
請求項１に記載の発明は、被めっき面の外周縁をシールリングでシールし被めっき面を上向きにして被処理材を保持して、被めっき面上に前記シールリングで包囲されて上方に開口するめっき槽を形成する保持部と、前記保持部で保持した被処理材の裏面に接触させて被処理材を加熱する加熱流体であって、温水、アルコールまたは有機溶液からなり、下記のめっき液の温度と同じ温度の加熱流体を保持する加熱流体保持部と、前記保持部で保持した被処理材の被めっき面上に形成される前記めっき槽内に所定の温度に加熱しためっき液を供給するめっき液供給部とを有することを特徴とする無電解めっき装置である。
【００１３】
このように、被処理材の裏面に加熱流体を接触させて被処理材を加熱することで、加熱流体が被処理材の裏面の凹凸に追従してその全面で接触するようにして、接触面積を増大させて効率よく被処理材への熱伝導を行い、しかも熱容量が大きな流体を熱源に利用することで、被処理材を短時間でより均一に加熱することができる。例えば、温度が６０℃となるようにコントロールした温水を半導体ウエハの裏面に接触させることで、約２〜３秒で半導体ウエハをその表面温度が６０℃になるように加熱することができる。しかも、被処理材全体をめっき液中に浸漬することがないので、めっき液の管理が容易となる。
【００１６】
請求項２に記載の発明は、前記めっき槽の上方を開閉自在に覆うとともに、該めっき槽内に供給されためっき液の放熱を防ぐヒータを備えた蓋体を更に有することを特徴とする請求項１記載の無電解めっき装置である。これにより、被めっき面の上に供給されためっき液表面からの放熱を抑えることができる。
【００１８】
請求項３に記載の発明は、前記保持部は、上下動及び回転自在に構成されていることを特徴とする請求項１または２記載の無電解めっき装置である。これにより、保持部を下降させて、保持部で保持した被処理材の裏面を加熱流体に接触させることができる。また、保持部を回転させて、保持部で保持した被処理材の被めっき面に供給しためっき液で被めっき面を均一に濡らしたり、めっき後のめっき液の液切りを行ったりすることができる。
【００１９】
請求項４に記載の発明は、前記保持部は、チルト自在に構成されていることを特徴とする請求項１乃至３のいずれか一項に記載の無電解めっき装置である。これにより、保持部で保持した被処理材を加熱流体の水面に対して傾斜させた状態で、被処理材の裏面を加熱流体に接触させ、しかる後、被処理材を水平に戻すことで、被処理材の裏面に気泡が残ってしまうことを防止することができる。また、めっき終了後に被処理材を傾斜させることで、被処理材の被めっき面上のめっき液を１ヶ所に集めて排出し易いようにすることができる。
【００２０】
請求項５に記載の発明は、前記めっき液供給部は、上下動自在で、前記めっき槽の上方を覆う位置と該位置の側方の待避位置との間を移動自在な蓋体を兼ねたヘッド部を有する揺動自在な揺動アームと、このヘッド部に取付けためっき液供給ノズルを有することを特徴とする請求項１乃至４のいずれか一項に記載の無電解めっき装置である。これにより、めっき処理にあたっては、ヘッド部を保持部で保持した被処理材の上方を覆う所定の位置に位置させ、それ以外は、ヘッド部を待避位置に待避させることで、ヘッド部が被処理材の搬送等を阻害してしまうことを防止することができる。
【００２１】
請求項６に記載の発明は、前記めっき液供給部は、めっき１回分の所定量のめっき液を保持し該めっき液を自重で前記めっき液供給ノズルから前記めっき槽内に供給するめっき液保持タンクと、このめっき液保持タンクで保持しためっき液を所定の温度に維持する機構を更に有することを特徴とする請求項５記載の無電解めっき装置である。これにより、例えば無電解めっきで直径２００ｍｍのウエハ表面に保護膜形成用の銅めっきを行う際には、約１００〜２００ｃｃのめっき液が、直径３００ｍｍのウエハ表面に保護膜形成用の銅めっきを行う際には、約２００〜４００ｃｃのめっき液が必要となるが、この所定量のめっき液を、液温を低下させることなく、常に一定の温度に保持した状態で、自由落下により瞬時（例えば１〜５秒）に被処理材の被めっき面に供給することができる。
【００２２】
請求項７に記載の発明は、前記ヘッド部には、めっき前処理液を保持し該めっき前処理液を自重で前記めっき槽内に供給するめっき前処理液保持タンクが備えられていることを特徴とする請求項５または６記載の無電解めっき装置である。このめっき前処理液としては、前処理洗浄を行う洗浄液や、触媒付与処理を行う触媒付与液などが挙げられる。これにより、保持部で被処理材を保持した状態で、例えば洗浄や触媒付与等のめっき前処理とめっき処理とを１槽で連続して行うことができる。この洗浄液としては、Ｈ_２ＳＯ_４，ＨＦ，ＨＣｌ，ＮＨ_３，ＤＭＡＢ（ジメチルアミンボラン）またはしゅう酸等が、触媒付与液としては、ＰｄＳＯ_４やＰｄＣｌ_２等が挙げられる。
【００２３】
請求項８に記載の発明は、前記ヘッド部には、前記めっき槽内に純水を供給する純水供給ノズルが備えられていることを特徴とする請求項５乃至７のいずれか一項に記載の無電解めっき装置である。これにより、めっき処理とめっき処理後の純水によるリンス洗浄とを１槽で連続して行うことができる。
【００２４】
請求項９に記載の発明は、前記めっき槽内に供給されためっき液を回収するめっき液回収ノズルを更に有することを特徴とする請求項１乃至８のいずれか一項に記載の無電解めっき装置である。これにより、めっき液をめっき液回収ノズルから回収して再使用することで、めっき液の使用量を減少させ、ランニングコストを低くすることができる。
【００２５】
請求項１０に記載の発明は、前記保持部で保持した被処理材と前記めっき槽の上方を覆うように位置させた前記ヘッド部との間の空間に不活性ガスを導入し、該空間を所定の温度の不活性ガス雰囲気に保持する不活性ガス導入部を更に有することを特徴とする請求項７乃至９のいずれか一項に記載の無電解めっき装置である。これにより、めっき処理中に保持部で保持した被処理材と該被処理材の上面を覆うヘッド部との間の空間に不活性ガスを導入し、この空間を所定の温度の不活性ガス雰囲気にすることで、めっき液の液面が空気と接触し、空気中の酸素をめっき液中に取込んでめっき液中の溶存酸素量が増加し、還元剤の酸化作用を抑制してめっきが析出しづらくなることを防止し、同時にめっき液の液温がめっき中に低下することを防止することができる。また、自己分解しやすい還元剤（たとえばＤＭＡＢ，ＧＯＡ）の場合は空気との接触を防ぐことで液のライフを延ばすことも可能である。この不活性ガスは、例えばＮ_２ガスで、このガスの温度は、例えばめっき液の液温が７０℃の時、６０〜７０℃、好ましくは６５〜７０℃程度である。
【００２６】
請求項１１に記載の発明は、前記めっき液保持タンクと前記めっき液供給ノズルの内部に洗浄液を流して洗浄する洗浄液導入部を更に有することを特徴とする請求項６乃至１０のいずれか一項に記載の無電解めっき装置である。これにより、めっき液保持タンクやめっき液供給ノズルの壁面に生成された付着物を、定期的或いは任意の時期に洗浄して除去することができる。この洗浄液としては、例えば、純水や、ＨＮＯ_３，王水またはＨＦ等の洗浄用薬品が挙げられる。
【００２７】
請求項１２に記載の発明は、被めっき面の周縁部をシールリングでシールし被めっき面を上向きにして保持して、被めっき面上に前記シールリングで包囲されて上方に開口するめっき槽を形成した被処理材の裏面を、温水、アルコールまたは有機溶液からなり、下記のめっき液と同じ温度の加熱流体に接触させて被処理材を加熱しつつ、被めっき面上に形成された前記めっき槽内に所定の温度に加熱した所定量のめっき液を供給してめっきを行うことを特徴とする無電解めっき方法である。
【００２８】
【発明の実施の形態】
以下、本発明の実施の形態を図面を参照して説明する。
図１は、半導体装置における銅配線形成例を工程順に示すもので、先ず、図１（ａ）に示すように、半導体素子を形成した半導体基材１上の導電層１ａの上にＳｉＯ_２からなる絶縁膜２を堆積し、この絶縁膜２の内部に、例えばリソグラフィ・エッチング技術によりコンタクトホール３と配線用の溝４を形成し、その上にＴａＮ等からなるバリア層５、更にその上に電解めっきの給電層としての銅シード層６をスパッタリング等により形成する。
【００２９】
そして、図１（ｂ）に示すように、半導体基板Ｗの表面に銅めっきを施すことで、半導体基板Ｗのコンタクトホール３及び溝４内に銅を充填させるとともに、絶縁膜２上に銅層７を堆積させる。その後、化学的機械的研磨（ＣＭＰ）により、絶縁膜２上の銅層７を除去して、コンタクトホール３及び配線用の溝４に充填させた銅層７の表面と絶縁膜２の表面とをほぼ同一平面にする。これにより、図１（ｃ）に示すように、絶縁膜２の内部に銅シード層６と銅層７からなる配線８を形成する。次に、基板Ｗの表面に、例えば無電解Ｎｉ−Ｂめっきを施して、図１（ｄ）に示すように、配線８の露出表面にＮｉ−Ｂ合金膜からなる保護膜（めっき膜）９を選択的に形成して配線８を保護する。
【００３０】
図２及び図３は、本発明の実施の形態の無電解めっき装置を示す。この無電解めっき装置は、例えば図１におけるバリア層５の形成、銅シード層６の補強、銅層７を堆積、更には、保護膜（めっき膜）９の形成に使用される。
【００３１】
この無電解めっき装置１０は、半導体ウエハ等の基板（被処理材）Ｗを該基板Ｗの表面（被めっき面）を上向き（フェースアップ）にして保持する基板保持部１２を有している。この基板保持部１２は、下記のように、基板Ｗを加熱する加熱流体を保持する加熱流体保持部４０を有する処理槽１４と、この処理槽１４の周囲を包囲する基板押圧部１６とから主に構成され、この基板押圧部１６には、処理槽１４の上方に延出する延出部１８が一体に連接され、この延出部１８の内周縁部の下面に、シールリング２０が下方に突出して取付けられている。
【００３２】
処理槽１４は、モータ２２の駆動に伴ってベルト２３を介して回転する主軸２４の上端に連結され、上面には、基板Ｗの大きさに沿った段差１４ａが設けられている。一方、基板押圧部１６は、この主軸２４を囲繞する基台２６の周辺部に立設したロッド２８の上端に連結されている。更に、基台２６と主軸２４に設けたフランジ２４ａとの間にシリンダ３０が配置され、このシリンダ３０の作動に伴って、基板押圧部１６が処理槽１４に対して相対的に上下動するようになっている。また、基台２６には、上方に突出して基板押圧部１６の延出部１８の下方に達する突上げピン３２が取付けられ、処理槽１４の該突上げピン３２と対向する位置には、上下に貫通する貫通孔１４ｂが設けられている。
【００３３】
これにより、基板押圧部１６を処理槽１４に対して相対的に上昇させた状態で、この内部に基板Ｗを挿入し、この基板Ｗを突上げピン３２の上端に載置して保持し、この状態で基板押圧部１６を処理槽１４に対して相対的に下降させることで、基板Ｗを処理槽１４の上面の段差１４ａ内に位置させ、更に下降させることで、シールリング２０を基板Ｗの上面の外周縁部に圧接させて、ここをシールして基板Ｗを保持し、これによって、基板Ｗの上面とシールリング２０で包囲され上方に開口しためっき槽３４を形成する。そして、この逆の動作で基板Ｗの保持を解くようになっている。更に、モータ２２の駆動に伴って、基板保持部１２で基板Ｗを保持したまま、処理槽１４と基板押圧部１６が一体に回転するようになっている。
【００３４】
処理槽１４の上面には、例えば温水、アルコールまたは有機溶液等の加熱流体を保持し該加熱流体に基板Ｗの裏面を接触させて基板Ｗを加熱する加熱流体保持部４０が設けられている。つまり、この加熱流体保持部４０は、図３に示すように、段差１４ａから連続して基板Ｗの形状に沿った円状に形成された凹部４２と、この凹部４２よりも深く形成されて放射状に延びる複数の流路溝４４とを有しており、この流路溝４４は、同一深さで処理槽１４の外周部に達している。この各流路溝４４は、主軸２４の内部に設けた流体通路２４ｂに連通し、更に、この流体通路２４ｂは、例えば、加熱流体として加熱した純水を使用した場合には、純水供給源から延び、純水をめっき温度と同じ、例えば６０℃に加熱する純水加熱部４６を途中に介装した流体供給パイプ４８に接続されている。
【００３５】
これにより、純水供給源から供給され純水加熱部４６で加熱された加熱流体（温水）は、流体通路２４ｂを通過して加熱流体保持部４０内に流入し、主に流路溝４４に沿って流れた後、処理槽１４の外部に流出するようになっている。
【００３６】
そして、このようにして加熱流体保持部４０内に流入した加熱流体が、基板保持部１２で保持した基板Ｗの裏面に接触して、基板Ｗを加熱するのであり、これにより、加熱流体が基板Ｗの裏面の凹凸に追従してその全面で接触し、接触面積を増大させて効率よく基板Ｗへの熱伝導を行い、しかも熱容量が大きな温水等の加熱流体を熱源に利用することで、基板Ｗを短時間でより均一に加熱することができる。例えば、温度が６０℃となるようにコントロールした温水を半導体ウエハの裏面に接触させることで、約２〜３秒で半導体ウエハをその表面温度が６０℃になるように加熱することができる。しかも、基板Ｗの全体をめっき液中に浸漬することがないので、めっき液の管理が容易となる。
【００３７】
更に、この例では、処理槽１４の内部にヒータ５０が内蔵され、このヒータ５０で加熱流体保持部４０内を流れる加熱流体を加熱して、加熱流体の温度が徐々に低下することを防止できるようになっている。
【００３８】
基板押圧部１６の周囲には、加熱流体の飛散を防止し、加熱流体を集めてドレン５２ａから排出する飛散防止カバー５２が配置されている。更に、この飛散防止カバー５２の上部に位置して、モータ５６を介して開閉自在で、基板保持部１２で保持した基板Ｗの表面を覆って密閉に近い空間を形成する一対の蓋体５８が配置されている。この蓋体５８は、例えば１枚板で構成してもよい。
【００３９】
これにより、めっき中に蓋体５８を閉じて密閉に近い空間内に基板Ｗを位置させることで、基板Ｗからの放熱を蓋体５８で防止して、めっき中における基板Ｗの温度をより均一に維持し、しかも基板Ｗを基板保持部１２で保持して昇降させる際には、蓋体５８を開くことで、蓋体５８が基板保持部１２と干渉してしまうことを防止することができる。
【００４０】
更に、基板保持部１２の上方に位置して、基板Ｗの上面とシールリング２０で形成されためっき槽３４内に、所定の温度、例えば６０℃に加熱しためっき液（無電解めっき液）６０を供給するめっき液供給部６２が配置されている。このめっき液供給部６２は、揺動自在なアーム６４を有し、このアーム６４の先端に備えた噴射ノズル６６からめっき液６０を基板保持部１２で保持した基板Ｗに向けて均一に噴射するようになっている。このめっき液の温度は、例えば２５〜９０℃、好ましくは５５〜８５℃程度であり、更に好ましくは６０〜８０℃程度である。
【００４１】
なお、図示しないが、基板保持部１２の上方に位置して、めっき槽３４内のめっき液を吸引して回収する、上下動及び旋回自在なめっき液回収ノズルと、めっき後の基板Ｗの表面に超純水等の洗浄液を供給する洗浄ノズルが配置されている。
【００４２】
この実施の形態の無電解めっき装置にあっては、先ず基板押圧部１６を処理槽１４に対して相対的に上昇させた状態で、基板Ｗを基板押圧部１６の内部に挿入して、突上げピン３２の上に載置保持する。なお、この時、蓋体５８は開いた位置にある。一方、処理槽１４の加熱流体保持部４０内に、めっき液６０と同じ温度、例えば６０℃に加熱した温水等の加熱流体を導入し、流路溝４４を通過させてオーバーフローさせておく。
【００４３】
この状態で、基板押圧部１６を処理槽１４に対して相対的に下降させ、基板Ｗを処理槽１４の上面の段差１４ａ内に位置させ、更に下降させることで、シールリング２０を基板Ｗの上面の外周縁部に圧接させて、ここをシールして基板Ｗを保持し、これによって、基板Ｗの上面とシールリング２０で包囲され上方に開口しためっき槽３４を形成する。同時に、基板Ｗの裏面を処理槽１４の加熱流体保持部４０内に導入した加熱流体に接触させる。
【００４４】
そして、基板Ｗが加熱流体で加熱されて、加熱流体と同じ温度、例えば６０℃に達した時に、めっき液供給部６２の噴射ノズル６６から、所定の温度、例えば６０℃に加熱しためっき液６０を、基板Ｗの上面のシールリング２０で包囲されためっき槽３４内に、一定量（例えば直径２００ｍｍウエハでは約１００ｃｃ〜２００ｃｃ）注入する。めっき液の注入タイミングに合わせて、加熱流体の供給タイミングを調整することができるので、基板保持部１２上に基板が置かれてめっき液が注入されるまでの間に基板表面が乾燥してしまうことはない。
【００４５】
そして、蓋体５８を閉じて、基板Ｗの表面からの放熱を防止し、必要に応じて、ヒータ５０で加熱流体保持部４０内に導入した加熱流体を加熱して、この加熱流体の温度がめっき中に低下することを防止する。これにより、基板Ｗは、その全面に亘って加熱流体の温度に維持され、均一な膜厚のめっき膜が成長する。しかも、基板Ｗの外周縁部も加熱流体に浸漬されているので、基板の外周縁部の温度が低下することはない。この時、例えば基板Ｗを回転させて、被めっき面の水素の密度、溶存酸素濃度を均一な状態にすることもできる。
【００４６】
めっき処理が完了した後、加熱流体保持部４０内への加熱流体の導入を停止して、導入側から排出し、基板Ｗの上面のシールリング２０で包囲されためっき槽３４内のめっき液を吸引等により除去する。そして、基板Ｗを回転させつつ、洗浄液ノズル（図示せず）から洗浄液を基板Ｗの被めっき面に向けて噴射して、被めっき面を冷却すると同時に希釈化・洗浄することで無電解めっき反応を停止させる。
【００４７】
そして、基板押圧部１６を処理槽１４に対して相対的に上昇させ、基板Ｗを突上げピン３２で持上げて基板Ｗの保持を解き、しかる後、ロボットのハンド等でめっき後の基板を次工程に搬送する。
【００４８】
図４は、無電解めっき装置１０によって一連のめっき処理を行うめっき処理装置の全体構成を示す。このめっき処理装置は、各一対の無電解めっき装置１０、ロード・アンロード部７０、例えばＰｄ触媒を付与する触媒処理や露出配線表面に付着した酸化膜を除去する酸化膜除去処理等のめっき前処理を行うめっき前処理装置７２、粗洗浄可能な仮置き部７４及び後洗浄装置７６を有し、更にロード・アンロード部７０、後洗浄装置７６及び仮置き部７４の間で基板Ｗを搬送する第１搬送装置７８ａと、無電解めっき装置１０、めっき前処理装置７２及び仮置き部７４の間で基板Ｗを搬送する第２搬送装置７８ｂが備えられている。
【００４９】
次に、上記のように構成しためっき処理装置による一連のめっき処理の工程について説明する。まず、ロード・アンロード部７０に保持された基板Ｗを第１搬送装置７８ａにより取出し、仮置き部７４に置く。第２搬送装置７８ｂは、これをめっき前処理装置７２に搬送し、ここでＰｄＣｌ_２液等の触媒による触媒付与処理や露出配線表面に付着した酸化膜を除去する酸化膜除去処理等のめっき前処理を行い、しかる後リンスする。
【００５０】
第２搬送装置７８ｂは、基板Ｗをさらに無電解めっき装置１０に運び、ここで所定の還元剤と所定のめっき液を用いて無電解めっき処理を行う。次に、第２搬送装置７８ｂでめっき後の基板を無電解めっき装置１０から取出して仮置き部７４に運ぶ。仮置き部７４では、基板の粗洗浄を行う。そして、第１搬送装置７８ａは、この基板を後洗浄装置７６に運び、この後洗浄装置７６でペンシル・スポンジによる仕上げの洗浄とスピンドライによる乾燥を行って、ロード・アンロード部７０へ戻す。基板は後にめっき装置や酸化膜形成装置に搬送される。
【００５１】
図５は、図１に示す保護膜９を形成する一連のめっき処理（蓋めっき処理）を行うめっき処理装置の全体構成を示す。このめっき処理装置は、ロード・アンロード部８０、前処理部８２、Ｐｄ付着部８４、めっき前処理部８６、無電解めっき装置１０及び洗浄・乾燥処理部８８を有し、更に、搬送経路９０に沿って走行自在で、これらの間で基板の受渡しを行う搬送装置９２が備えられている。
【００５２】
次に、上記のように構成しためっき処理装置による一連のめっき処理（蓋めっき処理）の工程について説明する。まず、ロード・アンロード部８０に保持された基板Ｗを搬送装置９２により取出し、前処理部８２に搬送し、ここで、基板に例えば基板表面を再度洗浄する前処理を施す。そして、銅層７（図１参照）の表面にＰｄ付着部８４でＰｄを付着させて銅層７の露出表面を活性化させ、しかる後、めっき前処理部８６でめっき前処理、例えば中和処理を施す。次に、無電解めっき装置１０に搬送し、ここで、活性化した銅層７の表面に、例えばＣｏ−Ｗ−Ｐによる選択的な無電解めっきを施し、これによって、図１（ｄ）に示すように、銅層７の露出表面をＣｏ−Ｗ−Ｐ膜（保護膜）９で保護する。この無電解めっき液としては、例えば、コバルトの塩とタングステンの塩に、還元剤、錯化剤、ｐＨ緩衝剤及びｐＨ調整剤を添加したものがあげられる。
【００５３】
なお、研磨後に露出した表面に、例えば無電解Ｎｉ−Ｂめっきを施して、配線８の外部への露出表面に、Ｎｉ−Ｂ合金膜からなる保護膜（めっき膜）９を選択的に形成して配線８を保護するようにしてもよい。この保護膜９の膜厚は、０．１〜５００ｎｍ、好ましくは、１〜２００ｎｍ、更に好ましくは、１０〜１００ｎｍ程度である。
【００５４】
この保護膜９を形成する無電解Ｎｉ−Ｂめっき液としては、例えばニッケルイオン、ニッケルイオンの錯化剤、ニッケルイオンの還元剤としてのアルキルアミンボランまたは硼素化水素化合物を含有し、ｐＨ調整にＴＭＡＨ（水酸化テトラメチルアンモニウム）を使用して、ｐＨを５〜１２に調整したものが使用される。
【００５５】
次に、この蓋めっき処理後の基板Ｗを洗浄・乾燥処理部８８に搬送して洗浄・乾燥処理を行い、この洗浄・乾燥後の基板Ｗを搬送装置９２でロード・アンロード部８０のカセットに戻す。
なお、この例では、蓋めっき処理として、Ｃｏ−Ｗ−Ｐ無電解めっき処理を施す前に、Ｐｄを付着することによって活性化させた銅層７の露出表面をＣｏ−Ｗ−Ｐ膜で選択的に被覆するようにした例を示しているが、これに限定されないことは勿論である。
【００５６】
図６は、本発明の他の実施の形態の無電解めっき装置を示す。この無電解めっき装置１０ｃは、基板保持部１２で保持した基板Ｗの表面を開閉自在に覆う上下動自在な円板状の蓋体５８ａを備え、この蓋体５８ａとめっき液供給部６２とを一体化し、基板Ｗと蓋体５８ａで囲まれ保温空間をめっき液の温度付近に保つヒータ５９を蓋体５８ａに内蔵したものである。その他の構成は、図２及び図３に示すものと同様である。この例によれば、基板Ｗの被めっき面上に供給されためっき液表面からの放熱を抑えることができる。なお、処理槽１４にもヒータ５０を内蔵して、上下から加熱するようにしてもよい。
【００５７】
図７は、本発明の更に他の実施の形態の無電解めっき装置を示す。この無電解めっき装置１０ａは、基板（被処理材）Ｗを該基板Ｗの表面（被めっき面）を上向き（フェースアップ）にして保持する基板保持部１００と、この基板保持部１００の下方に配置された処理槽１０２を有している。基板保持部１００は、下端に内方に突出して基板Ｗの外周縁部を載置保持する保持爪１０４ａを有するハウジング１０４と、円筒状で、下端に内方に突出するシール爪１０６ａを有する基板押圧部１０６とを備え、シール爪１０６ａの下面には、シールリング１０８が下方に突出させて取付けられている。更に、基板押圧部１０６は、ハウジング１０４の内部に配置され、ハウジング１０４に取付けたシリンダ１１０の作動に伴って、ハウジング１０４に対して相対的に上下動するようになっている。
【００５８】
これにより、基板押圧部１０６をハウジング１０４に対して相対的に上昇させた状態で、この内部に基板Ｗを挿入して、ハウジング１０４の保持爪１０４ａで基板Ｗを載置保持し、この状態で基板押圧部１０６をハウジング１０４に対して相対的に下降させることで、シールリング１０８を基板Ｗの上面の外周縁部に圧接させて、ここをシールして基板Ｗを保持し、これによって、基板Ｗの上面と基板押圧部１０６で包囲され上方に開口しためっき槽１１２を形成する。そして、この逆の動作で基板Ｗの保持を解くようになっている。
【００５９】
基板保持部１００は、ハウジング１０４を介してモータ１１４に接続され、このモータ１１４は、アーム１１６の自由端に固着されている。更に、このアーム１１６は、モータ１１８の駆動に伴って上下動する上下動板１２０に取付けられ、更にチルト用のモータ１２１の駆動に伴って、上下方向にチルトするようになっている。これによって、基板保持部１００は、回転、上下動及びチルト自在で、これらの複合動作を行えるようになっている。
【００６０】
処理槽１０２の上面には、温水等の加熱流体を保持して基板Ｗを加熱する、基板Ｗより大きな内径の凹部からなる加熱流体保持部１２２が備えられている。この加熱流体保持部１２２は、溢流堰１２４に包囲され、この溢流堰１２４の外方に加熱流体排出路１２６が形成され、この加熱流体排出路１２６にドレン１２８が設けられている。更に、加熱流体保持部１２２は、例えば加熱流体として加熱した純水を使用する場合は、純水供給源から延び、純水をめっき温度と同じ、例えば６０℃に加熱する純水加熱部４６を途中に介装した加熱流体供給パイプ４８に接続されている。
【００６１】
これにより、純水供給源から供給され純水加熱部４６で加熱された加熱流体（温水）は、加熱流体保持部１２２内に流入し、溢流堰１２４をオーバーフローして処理槽１０２の外部に流出するようになっている。
【００６２】
更に、基板保持部１００の側方には、基板Ｗの上面と基板押圧部１０６で形成されためっき槽１１２内に、所定の温度、例えば６０℃に加熱しためっき液（無電解めっき液）６０を供給するめっき液供給部１３０が配置されている。このめっき液供給部１３０は、先端にめっき液を噴射する噴射ノズル１３２を有している。
【００６３】
この実施の形態によれば、前述のようにして基板Ｗを保持した基板保持部１００を下降させ、この基板Ｗの裏面を加熱流体保持部１２２に保持した加熱流体に接触させて基板Ｗを加熱し、この基板Ｗがめっき温度に達した時に、めっき液供給部１３０から基板Ｗの上面と基板押圧部１０６で形成されためっき槽１１２内に所定の温度のめっき液を注入して無電解めっきを行う。
【００６４】
ここで、この例によれば、基板保持部１００で保持した基板Ｗを処理槽１０２内の加熱流体の水面に対して傾斜させた状態で、基板Ｗの裏面を加熱流体に接触させ、しかる後、基板Ｗを水平に戻すことで、基板Ｗの裏面に気泡が残ってしまうことを防止することができる。また、めっき終了後に基板Ｗを傾斜させることで、基板Ｗの被めっき面上の無電解めっき液を１カ所に集めて排出し易いようにすることができる。
【００６５】
図８は、本発明の更に他の実施の形態の無電解めっき装置を示す。この無電解めっき装置１０ｂの前記図７に示す無電解めっき装置１０ａと異なる点は、以下の通りである。すなわち、ハウジング１０４を下方に延出させ、このハウジング１０４の下方延出部に取付けた従動ローラ１４０とモータ１４２に取付けた駆動ローラ１４４との間にベルト１４６を掛け渡し、モータ１４８を介して上下動する上下動板１５０に取付けたフランジ１５２に前記モータ１４２を固着して、基板保持部１００が回転及び上下動するようにしている。
【００６６】
また、処理槽１０２の内部に加熱流体供給通路１０２ａと加熱流体排出通路１０２ｂを設け、この処理槽１０２の周囲をめっき液排出用のドレン１５４ａを有する飛散防止カバー１５４で囲繞している。更に、めっき液供給部１５６は、飛散防止カバー１５４の側方を上下に延び、直角に屈曲して基板保持部１００のほぼ中央の直上方に達し、この先端に下方に向けて取付けた噴射ノズル１５８からめっき液を基板Ｗの上面（被めっき面）に向けて噴射するようにしている。その他の構成は、図７に示すものと同様である。
【００６７】
この例によれば、基板保持部１００の回転及び上下動機構をハウジング１０４の下方に配置することで、基板保持部１００の上方を開放させて、めっき液供給部１５６を基板保持部１００の上方に配置し、これによって、めっき液の供給を容易に行うことができる。
【００６８】
図９及び図１０は、本発明の更に他の実施の形態の無電解めっき装置を示す。この無電解めっき装置１０ｄは、基板（被処理材）Ｗを該基板Ｗの表面（被めっき面）を上向き（フェースアップ）にして保持する基板保持部２００を有している。この基板保持部２００は、下記のように、基板Ｗを加熱する加熱流体を保持する加熱流体保持部２１６を有する処理槽２０２と、この処理槽２０２の周囲を包囲する円筒状のハウジング２０４とから主に構成され、このハウジング２０４の上端には、中空円板状の支持板２０６が固着され、この支持板２０６の内周面にシールリング２０８が下方に突出して取付けられている。
【００６９】
処理槽２０２の上面には、基板Ｗの周縁部を支持するリング状の基板ステージ２１０と、基板Ｗの外周部に位置して基板Ｗのずれを防止するガイドリング２１２が取付けられている。そして、この処理槽２０２は、ハウジング２０４に対して相対的に上下動自在で、処理槽２０２をハウジング２０４に対して相対的に下降させた状態で、ハウジング２０４の内部に基板Ｗを挿入し、この基板Ｗを基板ステージ２１０の上面に載置して保持し、この状態で処理槽２０２をハウジング２０４に対して相対的に上昇させることで、シールリング２０８を基板Ｗの上面の外周縁部に圧接させて、ここをシールして基板Ｗを保持し、これによって、基板Ｗの上面とシールリング２０８で包囲され上方に開口しためっき槽２１４を形成する。そして、この逆の動作で基板Ｗの保持を解くようになっている。更に、図示しないモータの駆動に伴って、基板保持部２００で基板Ｗを保持したまま、処理槽２０２とハウジング２０４が一体に回転するようになっている。
【００７０】
処理槽２０２の上面には、例えば温水、アルコールまたは有機溶液等の加熱流体を保持し該加熱流体に基板Ｗの裏面を接触させて基板Ｗを加熱する加熱流体保持部２１６が設けられている。この加熱流体保持部２１６は、上方に開く横断面ラッパ状の流路で構成され、この加熱流体保持部２１６は、前述と同様に、例えば、純水を６０℃に加熱する純水加熱部を途中に介装した流体供給パイプに接続されている。そして、この加熱流体保持部２１６をオーバーフローした加熱流体は、処理槽２０２とハウジング２０４との間を通って外部に流出するようになっている。なお、ハウジング２０４の周囲には、前述のように、加熱流体の飛散を防止する飛散防止カバー（図示せず）が配置されている。
【００７１】
基板保持部２００の上方に位置して、基板Ｗの上面とシールリング２０８で形成されためっき槽２１４内に、所定の温度、例えば６０℃に加熱しためっき液（無電解めっき液）６０を供給するめっき液供給部２２０が配置されている。このめっき液供給部２２０は、上下動かつ揺動自在な揺動アーム２２２を有し、この揺動アーム２２２の自由端に、めっき槽２１４の開口部を略覆う形状に形成された円板状のヘッド部２２４が取付けられている。そして、このヘッド部２２４は、揺動アーム２２２の揺動に伴って、図１０に示すようにして、基板保持部２００の上方を覆う位置と待避位置との間を移動し、これによって、めっき処理にあたっては、ヘッド部２２４を基板保持部２００で保持した基板Ｗの上方を覆う所定の位置に位置させ、それ以外は、ヘッド部２２４を待避位置に待避させることで、ヘッド部２２４が基板Ｗの搬送等を阻害してしまうことを防止するようになっている。
【００７２】
ヘッド部２２４のほぼ中心に位置して、下方に開口するめっき液供給ノズル２２６が、このめっき液供給ノズル２２６の上方に位置して、めっき１回分の所定量のめっき液を保持する容積を有するめっき液保持タンク２２８がそれぞれ配置され、めっき液供給ノズル２２６とめっき液保持タンク２２８は、めっき液配管２３０で接続されている。めっき液保持タンク２２８には、めっき液供給管２３２とめっき液排出管２３４がそれぞれ接続され、更に、めっき液配管２３０、めっき液供給管２３２及びめっき液排出管２３４には、開閉バルブ（図示せず）が介装されている。
【００７３】
これにより、非めっき時には、めっき液配管２３０の開閉バルブを閉じ、めっき液供給管２３２とめっき液排出管２３４の開閉バルブを開いて、めっき液保持タンク２２８内のめっき液を循環させることで、めっき液保持タンク２２８の内部に、常に一定の温度で、所定量のめっき液を保持する。そして、めっき液配管２３０の開閉バルブを開き、めっき液供給管２３２及びめっき液排出管２３４の開閉バルブを閉じることで、めっき液保持タンク２２８の内部に保持した、一定の温度で、所定量のめっき液を、その自重によって、めっき液供給ノズル２２６から瞬時（例えば１〜５秒）に基板Ｗの上面とシールリング２０８で形成されためっき槽２１４内に供給できるようになっている。
【００７４】
めっき液供給ノズル２２６の上方に位置して、例えば、めっきの前処理洗浄を行う洗浄液や、触媒付与処理を行う触媒付与液等のめっき前処理液を保持するめっき前処理液保持タンク２３６が備えられ、このめっき前処理液保持タンク２３６とめっき液供給ノズル２２６とはめっき前処理液配管２３８で接続されている。更に、めっき前処理液保持タンク２３６には、めっき前処理液供給管２４０とめっき前処理液排出管２４２がそれぞれ接続され、めっき前処理液配管２３８、めっき前処理液供給管２４０及びめっき前処理液排出管２４２には、開閉バルブ（図示せず）が介装されている。
【００７５】
これにより、前述のめっき液の場合と同様に、非めっき前処理時には、めっき前処理液保持タンク２３６の内部に、常に一定の温度で、所定量のめっき前処理液を保持し、めっき前処理時に、開閉バルブを介して、めっき前処理液保持タンク２３６の内部に保持しためっき前処理液を、その自重によって、めっき液供給ノズル２２６から瞬時（例えば１〜５秒）に基板Ｗの上面とシールリング２０８で形成されためっき槽２１４内に供給できるようになっている。なお、この例では、めっき液供給ノズル２２６がめっき前処理液を供給するノズルを兼用した例を示しているが、別々に設けてもよい。また複数のめっき前処理を行う場合には、複数のめっき前処理液保持タンクを備え、これらの各めっき前処理液保持タンクに保持しためっき前処理液を順次基板Ｗの被めっき面に供給するようにしてもよいことは勿論である。
【００７６】
このように構成することで、基板保持部２００で基板Ｗを保持した状態で、例えば洗浄や触媒付与等の前処理とめっき処理を１槽で連続して行うことができる。このめっきの前処理洗浄を行う洗浄液としては、Ｈ_２ＳＯ_４，ＨＦ，ＨＣｌ，ＮＨ_３，ＤＭＡＢ（ジメチルアミンボラン）またはしゅう酸等が、触媒付与処理を行う触媒付与液としては、ＰｄＳＯ_４やＰｄＣｌ_２等が挙げられる。
【００７７】
ヘッド部２２４には、基板保持部２００で保持した基板Ｗの上面（被めっき面）に純水を供給する純水供給ノズル２５０が備えられている。これにより、めっき処理後の基板の表面に純水供給ノズル２５０から純水を供給することで、めっき処理とめっき処理後の純水によるリンス洗浄とを１槽で連続して行うことができるようになっている。
【００７８】
ヘッド部２２４には、基板保持部２００で保持した基板Ｗの被めっき面に供給されためっき液を回収するめっき液回収ノズル２５２と、基板保持部２００で保持した基板Ｗの被めっき面に供給されためっき前処理液を回収するめっき前処理液回収ノズル２５４とが備えられている。これにより、めっき液をめっき液回収ノズル２５２から回収して再使用したり、更には、必要に応じて、めっき前処理液をめっき前処理液回収ノズル２５４から回収して再使用したりすることで、めっき液やめっき前処理液の使用量を減少させて、ランニングコストを低くすることができる。
【００７９】
めっき液供給ノズル２２６には、例えばＮ_２ガス等の加熱した不活性ガスを導入する不活性ガス導入路（不活性ガス導入部）２５６が接続され、この不活性ガス導入路２５６からめっき液供給ノズル２２６の内部に導入された加熱した不活性ガスは、めっき液供給ノズル２２６の内部をパージした後、基板保持部２００で保持した基板Ｗに向けて噴射されるようになっている。これにより、基板保持部２００で保持した基板Ｗと該基板Ｗの上面を覆うように位置させたヘッド部２２４との間の空間に不活性ガスを導入し、この空間を所定の温度の不活性ガス雰囲気に保持することで、めっき液の液面が空気と接触し、空気中の酸素をめっき液中に取込んでめっき液中の溶存酸素量が増加し、還元剤の酸化作用を抑制してめっきが析出しづらくなることを防止し、同時にめっき液の液温がめっき中に低下することを防止することができるようになっている。又は、めっき液注入前にヘッド部２２４と基板Ｗに囲まれた部分を不活性ガス雰囲気で所定の温度にしておくことで、めっき液注入時の空気の混入や液温低下を防止することができる。このＮ_２ガス等の不活性ガスの温度は、例えばめっき液の液温が７０℃の時、６０〜７０℃（めっき液の温度−１０℃〜めっき液の温度）、好ましくは６５〜７０℃（めっき液の温度−５℃〜めっき液の温度）程度である。
【００８０】
めっき液保持タンク２２８には洗浄液導入路（洗浄液導入部）２６０ａが、めっき前処理液保持タンク２３６には洗浄液導入路（洗浄液導入部）２６０ｂがそれぞれ接続されている。これによって、この洗浄液導入路２６０ａからめっき液保持タンク２２８に導入された洗浄液が、この内部、めっき液配管２３０及びめっき液供給ノズル２２６の内部を順に流れ、また洗浄液導入路２６０ｂからめっき前処理液保持タンク２３６に導入された洗浄液が、この内部、めっき前処理液配管２３８及びめっき液供給ノズル２２６の内部を順に流れ、これらの内壁面に生成された付着物を洗浄して除去できるようになっている。この洗浄は、定期的、或いは任意の時期に行うことができる。この洗浄液としては、例えば、純水や、ＨＮＯ_３，王水またはＨＦ等の洗浄用薬品が挙げられる。
【００８１】
なお、この例にあっては、ヘッド部２２４の内部に、基板保持部２００で保持した基板Ｗとヘッド部２２４で囲まれ保温空間をめっき液の温度付近に保つヒータ２６２が内蔵されている。
【００８２】
この実施の形態の無電解めっき装置によるめっき処理を、図１１を参照して説明する。先ず処理槽２０２をハウジング２０４に対して相対的に下降させた状態で、基板Ｗをハウジング２０４の内部に挿入して、基板ステージ２１０の上に載置保持する。なお、この時、ヘッド部２２４は待避位置にある。この状態で、処理槽２０２をハウジング２０４に対して相対的に上昇させ、シールリング２０８を基板Ｗの上面の外周縁部に圧接させて、ここをシールして基板Ｗを保持し、これによって、基板Ｗの上面とシールリング２０８で包囲され上方に開口しためっき槽２１４を形成する。
【００８３】
次に、ヘッド部２２４を基板保持部２００の直上方位置まで移動させ、更に下降させる。この状態で、めっき前処理液保持タンク２３６で保持した、例えば洗浄液や触媒付与液等の一定量のめっき前処理液を、その自重により、めっき前処理液供給ノズルを兼用しためっき液供給ノズル２２６から基板保持部２００で保持した基板の被めっき面に瞬時に供給してめっき前処理を行う。このめっき前処理終了後、基板Ｗの被めっき面上に残っためっき前処理液をめっき前処理液回収ノズル２５４で回収し、必要に応じて再利用する。
【００８４】
次に、処理槽２０２の加熱流体保持部２１６内に、めっき液６０と同じ温度、例えば７０℃に加熱した温水等の加熱流体を導入し、基板保持部２００で保持した基板Ｗの裏面を処理槽２０２の加熱流体保持部２１６内に導入した加熱流体に接触させ、オーバーフローさせる。そして、基板Ｗが加熱流体で加熱されて、加熱流体と同じ温度、例えば７０℃に達した時に、めっき液保持タンク２２８で保持した一定量（例えば直径２００ｍｍウエハでは約１００〜２００ｃｃ、直径３００ｍｍウエハでは約２００〜４００ｃｃ）で一定の温度のめっき液を、その自重により、めっき液供給ノズル２２６から基板保持部２００で保持した基板の被めっき面に瞬時に供給してめっき処理を行う。
【００８５】
このめっき処理時に、不活性ガス導入路２５６からめっき液供給ノズル２２６の内部に加熱した不活性ガスを導入し、この不活性ガスでめっき液供給ノズル２２６の内部をパージし、更に基板保持部２００で保持した基板Ｗと該基板Ｗの上面を覆うように位置させたヘッド部２２４との間の空間に不活性ガスを導入し、この空間を所定の温度の不活性ガス雰囲気に保持する。
【００８６】
そして、必要に応じて、ヒータ２６２でめっき液を加熱して、めっき液の温度がめっき中に低下することを防止する。これにより、基板Ｗは、その全面に亘って加熱流体の温度に維持され、均一な膜厚のめっき膜が成長する。しかも、基板Ｗの外周縁部も加熱流体に浸漬されているので、基板の外周縁部の温度が低下することはない。この時、例えば基板Ｗを回転させて、被めっき面の水素の離脱、溶存酸素濃度を均一な状態にすることもできる。
【００８７】
めっき処理が完了した後、加熱流体保持部２１６内への加熱流体の導入を停止して、導入側から排出し、基板Ｗの上面のシールリング２０８で包囲されためっき槽２１４内のめっき液をめっき液回収ノズル２５２から負圧吸引等により回収し、必要に応じて再使用する。そして、不活性ガス導入路２５６からの不活性ガスの導入を停止した後、基板Ｗを回転させつつ、純水供給ノズル２５０から純水を基板Ｗの被めっき面に向けて噴射して、被めっき面を冷却すると同時に希釈化・洗浄することで無電解めっき反応を停止させる。しかる後、基板Ｗを高速で回転させて液切りを行う。
【００８８】
そして、ヘッド部２２４を上昇させ、待避部に待避させた後、処理槽２０２をハウジング２０４に対して相対的に下降させて基板Ｗの保持を解き、しかる後、ロボットのハンド等でめっき後の基板を次工程に搬送する。
【００８９】
この実施の形態のめっき装置によれば、めっき前処理、めっき処置、純水リンス及び液切りといった各処理を１槽で連続して行うことができる。これにより、基板Ｗの表面（被めっき面）をウェットのまま、つまり乾燥してしまうことを防止しつつ、各処理を行うとともに、槽の数を減少させて、設置スペースを減少させることができる。
【００９１】
【発明の効果】
以上説明したように、本発明によれば、めっき処理中に被処理材の被めっき面内に温度むらが生じたり、めっき温度がめっき処理中に変化してしまうことを防止し、これによって、被めっき面の全域に亘ってより温度がより均一になるようにして、被めっき材の被めっき面により均一な膜厚のめっき膜を形成することができる。
【図面の簡単な説明】
【図１】銅めっきにより銅配線を形成する例を工程順に示す図である。
【図２】本発明の実施の形態の無電解めっき装置を示す断面図である。
【図３】図２の処理槽の平面図である。
【図４】図２に示す無電解めっき装置を備えためっき処理装置の一例を示す平面配置図である。
【図５】図２に示す無電解めっき装置を備えためっき処理装置の他の例を示す平面配置図である。
【図６】本発明の実施の形態の無電解めっき装置の他の例を示す断面図である。
【図７】本発明の実施の形態の無電解めっき装置の更に他の例を示す断面図である。
【図８】本発明の実施の形態の無電解めっき装置の更に他の例を示す断面図である。
【図９】本発明の実施の形態の無電解めっき装置の更に他の例を示す断面図である。
【図１０】図９に示す無電解めっき装置の平面図である。
【図１１】図８に示す無電解めっき装置でめっきを行う時の処理の手順を示すフローチャートである。
【符号の説明】
６銅シード層
７銅層
８配線
９保護膜
１０，１０ａ，１０ｂ，１０ｃ，１０ｄ無電解めっき装置
１２，１００，２００基板保持部
１４，１０２，２０２処理槽
１６，１０６基板押圧部
２０，１０８，２０８シールリング
２４主軸
３４，１１２，２１４めっき槽
４０，１２２，２１６加熱流体保持部
４２加熱流体保持部
４４流路溝
５０，２６２ヒータ
５２，１５２飛散防止カバー
５８，５８ａ蓋体
６０めっき液
６２，１３０，１５６めっき液供給部
６６、１３２，１５８噴射ノズル
７０ロード・アンロード部
７２前処理装置
７４仮置き部
７６後洗浄装置
８０ロード・アンロード部
８２前処理部
８４Ｐｄ付着部
８６前処理部
８８洗浄・乾燥処理部
１０４ハウジング
１０４ａ保持爪
１０６ａシール爪
１２４溢流堰
２０４ハウジング
２２２揺動アーム
２２４ヘッド部
２２６めっき液供給ノズル
２２８めっき液保持タンク
２３６めっき前処理液保持タンク
２５０純水供給ノズル
２５２めっき液回収ノズル
２５４めっき前処理液回収ノズル
２５６不活性ガス導入路（不活性ガス導入部）
２６０ａ，２６０ｂ洗浄液導入路（洗浄液導入部）[0001]
BACKGROUND OF THE INVENTION
The present invention Electroless Plating equipment and Electroless With regard to the plating method, in particular, an embedded wiring is formed by embedding a conductor such as copper or silver in a fine concave portion for wiring provided on the surface of a substrate such as a semiconductor substrate, or the surface of the wiring thus formed is formed. An electroless plating apparatus used to form a protective film for protection, and Electroless The present invention relates to a plating method.
[0002]
[Prior art]
Electroless plating is a method in which metal ions in the plating solution are chemically reduced to form a plating film on the surface to be treated without applying electricity from the outside. It is widely used for nickel-phosphorous, nickel-boron plating, copper plating for printed wiring boards, and the like.
[0003]
As this electroless plating apparatus, there are a plating tank that holds the electroless plating solution while overflowing, and a vertically movable holding part that is disposed on the upper part of the plating tank and holds a workpiece such as a substrate sideways. The material to be treated held by this holding part is immersed in the plating solution in the plating tank (so-called soaking), and the material to be treated such as the substrate is held upward (face-up). And a plating solution supply unit for supplying an electroless plating solution to the upper surface (surface to be plated) of the material to be processed held by the holding unit, on the upper surface of the material to be processed held by the holding unit. In general, an electroless plating solution flowing along the surface is known.
[0004]
In recent years, with the increase in the speed and integration of semiconductor chips, as a metal material for forming a wiring circuit on a semiconductor substrate, copper (Cu) having low electrical resistivity and high electromigration resistance is used instead of aluminum or aluminum alloy. ) Is a prominent movement. This type of copper wiring is generally formed by embedding copper in a fine recess provided on the surface of the substrate. As a method of forming this copper wiring, there are methods such as CVD, sputtering and plating, but plating is common. In any case, after a copper layer is formed on the surface of the substrate, the surface is polished flat by chemical mechanical polishing (CMP).
[0005]
In this type of wiring, after planarization, the surface of the wiring is exposed to the outside, and when forming a buried wiring thereon, for example, SiO 2 in the next step of interlayer insulating film formation process ₂ SiO for forming surface oxidation and contact holes during formation ₂ At the time of etching and the like, there are concerns about surface contamination due to etchant of the wiring exposed at the bottom of the contact hole, resist stripping, etc., and copper diffusion in copper wiring.
[0006]
For this reason, the surface of the wiring is selectively covered with a protective film (plating film) made of, for example, a Ni-B alloy film, which is strongly bonded to a wiring material such as silver or copper and has a low specific resistance (ρ). It is conceivable to protect. Here, the Ni-B alloy film is formed by electroless plating using an electroless plating solution having, for example, nickel ions, nickel ion complexing agents, alkylamine borane or borohydride compounds as nickel ion reducing agents. By applying, it can be selectively formed on the surface of copper or the like.
[0007]
[Problems to be solved by the invention]
Electroless plating can be applied to the main embedding material of copper wiring (Cu), formation of seed layer on barrier metal, or reinforcement of seed (Cu), formation of barrier metal itself, formation of lid material for copper wiring material (any Ni-P, Ni-B, Co-P, Ni-WP, Ni-Co-P, Co-WP, Co-WB), etc. The uniformity of the film thickness over the entire surface of the treatment material is required.
[0008]
Here, in electroless plating, the metal to be plated is deposited on the surface to be plated at the same time as the material to be treated comes into contact with the electroless plating solution, and the deposition rate of the plating metal varies depending on the temperature of the plating solution. For this reason, in order to form a plating film having a uniform thickness on the surface to be treated of the material to be treated, the temperature of the plating solution in the entire surface of the surface to be plated is uniform from the beginning when the plating solution contacts the material to be treated. Thus, it is required to keep this temperature constant throughout the entire plating process during contact.
[0009]
However, the conventional electroless plating apparatus generally holds a target material such as a substrate in close contact with the upper or lower surface of a holding unit having a built-in heater, and heats the target material via the heater. An electroless plating solution heated to a predetermined temperature is brought into contact with the surface to be plated of the material. For this reason, an air pool occurs between the material to be processed and the holding portion due to the unevenness of the material to be processed and the surface roughness of the holding portion, and the air pool acts as a heat insulating material. The heat conduction between the material to be treated and the holding part varies greatly, and a sheet of Teflon (trade name) having a poor thermal conductivity is generally adhered to the surface of the holding part. The temperature on the entire surface of the material to be treated is not uniform, and there is a problem in temperature uniformity.
[0010]
That is, the rate and film quality of electroless plating largely depend on the temperature of the electroless plating solution, and in order to ensure the uniformity of the film thickness over the entire surface of the material to be processed, the temperature of the plating solution is set to It is desirable to control the entire surface within a range of ± 1 ° C. However, in the conventional electroless plating apparatus, the temperature of the plating solution that contacts the material to be treated during plating varies by about ± 5 ° C. It was difficult to meet this demand. Furthermore, the escape of heat from the holding part and the escape of heat from the surface of the plating solution have been factors that reduce the temperature of the outer peripheral part of the material to be processed. As described above, even in the electroplating apparatus, the temperature on the entire surface of the material to be processed is not uniform and there is a problem in temperature uniformity.
[0011]
The present invention has been made in view of the above, and made it possible to easily form a uniform plating film on the surface to be treated of the material to be treated. Electroless Plating equipment and Electroless An object is to provide a plating method.
[0012]
[Means for Solving the Problems]
In the first aspect of the invention, the outer peripheral edge of the surface to be plated is With seal ring Seal With the surface to be plated facing upward Material to be treated Keep Holding Then, a plating tank surrounded by the seal ring and opening upward is formed on the surface to be plated. A holding fluid and a heating fluid that heats the material to be processed by contacting the back surface of the material to be processed held by the holding unit A heating fluid consisting of warm water, alcohol or organic solution and having the same temperature as the plating solution below A heated fluid holding part for holding the surface, and a plated surface of the material to be processed held by the holding part Inside the plating tank formed on In Heated to a given temperature And a plating solution supply unit that supplies the plating solution. Electroless It is a plating device.
[0013]
In this way, the heating fluid is brought into contact with the back surface of the material to be processed to heat the material to be processed, so that the heating fluid follows the irregularities on the back surface of the material to be processed and comes into contact with the entire surface. The material to be processed can be efficiently heated in a short time by efficiently conducting heat to the material to be processed and using a fluid having a large heat capacity as a heat source. For example, by bringing warm water controlled to a temperature of 60 ° C. into contact with the back surface of the semiconductor wafer, the semiconductor wafer can be heated to a surface temperature of 60 ° C. in about 2 to 3 seconds. In addition, since the entire material to be treated is not immersed in the plating solution, the management of the plating solution is facilitated.
[0016]
Claim 2 The invention described in , Above the plating tank While covering freely open and close, Inside the plating tank Lid with heater to prevent heat dissipation of plating solution supplied to Further It is characterized by having Electroless according to claim 1 It is a plating device. Thereby, the heat dissipation from the plating solution surface supplied on the to-be-plated surface can be suppressed.
[0018]
Claim 3 The invention according to claim 2, wherein the holding portion is configured to be vertically movable and rotatable. 1 or 2 Described Electroless It is a plating device. Thereby, a holding part can be lowered | hung and the back surface of the to-be-processed material hold | maintained by the holding part can be made to contact a heating fluid. In addition, by rotating the holding part, it is possible to evenly wet the plating surface with the plating solution supplied to the surface to be treated of the material held by the holding part, or to drain the plating solution after plating. it can.
[0019]
Claim 4 The invention according to claim 1, wherein the holding portion is configured to be tiltable. 3 Either One paragraph Described in Electroless It is a plating device. Thereby, in a state where the material to be processed held by the holding unit is inclined with respect to the water surface of the heating fluid, the back surface of the material to be processed is brought into contact with the heating fluid, and then the processing material is returned to the horizontal state It is possible to prevent bubbles from remaining on the back surface of the material to be processed. Further, by inclining the material to be treated after the end of plating, the plating solution on the surface to be treated of the material to be treated can be easily collected and discharged at one place.
[0020]
Claim 5 In the invention described in the above, the plating solution supply unit is movable up and down, Plating tank A position covering the top of At the side of the position 2. A swingable swinging arm having a head portion that also serves as a lid that is movable between a retracted position and a plating solution supply nozzle attached to the head portion. 4 Either One paragraph Described in Electroless It is a plating device. Thereby, in the plating process, the head unit is positioned at a predetermined position that covers the upper side of the material to be processed held by the holding unit, and otherwise, the head unit is retracted to the retracted position so that the head unit is processed. It is possible to prevent the conveyance of the material from being hindered.
[0021]
Claim 6 In the invention described in the above, the plating solution supply unit holds a predetermined amount of plating solution for one plating, and the plating solution is self-weighted from the plating solution supply nozzle. Inside the plating tank A plating solution holding tank supplied to the plating solution and a mechanism for maintaining the plating solution held in the plating solution holding tank at a predetermined temperature. 5 Described Electroless It is a plating device. Thus, for example, when performing copper plating for forming a protective film on a wafer surface having a diameter of 200 mm by electroless plating, about 100 to 200 cc of plating solution is applied to the surface of the wafer having a diameter of 300 mm. When performing, about 200 to 400 cc of plating solution is required, but this predetermined amount of plating solution is kept at a constant temperature without lowering the solution temperature, and is instantaneously (for example, by free fall) 1 to 5 seconds) can be supplied to the surface of the material to be treated.
[0022]
Claim 7 In the invention described in the above, the head portion holds the plating pretreatment liquid, and the plating pretreatment liquid is self-weighted. Inside the plating tank A plating pretreatment liquid holding tank is provided for supplying to the substrate. 5 or 6 Described Electroless It is a plating device. Examples of the plating pretreatment liquid include a cleaning liquid that performs pretreatment cleaning and a catalyst application liquid that performs a catalyst application process. Thereby, in the state which hold | maintained the to-be-processed material in the holding | maintenance part, for example, pre-plating processes, such as washing | cleaning and catalyst provision, and a plating process can be performed continuously by 1 tank. As this cleaning liquid, H ₂ SO ₄ , HF, HCl, NH ₃ , DMAB (dimethylamine borane) or oxalic acid may be used as a catalyst-providing liquid such as PdSO. ₄ And PdCl ₂ Etc.
[0023]
Claim 8 In the invention described in (2), the head portion includes the Inside the plating tank A pure water supply nozzle for supplying pure water to the water is provided. 5 to 7 Either One paragraph Described in Electroless It is a plating device. Thereby, the plating treatment and the rinsing with pure water after the plating treatment can be continuously performed in one tank.
[0024]
Claim 9 The invention described in the above Inside the plating tank A plating solution recovery nozzle for recovering the plating solution supplied to the substrate is further provided. 8 Either One paragraph Described in Electroless It is a plating device. Thereby, by recovering the plating solution from the plating solution recovery nozzle and reusing it, the amount of the plating solution used can be reduced and the running cost can be reduced.
[0025]
Claim 10 According to the invention described in item 3, the material to be processed held by the holding unit The plating tank of Upward An inert gas introduction part is further provided for introducing an inert gas into a space between the head part and the head part positioned so as to cover the atmosphere, and maintaining the space in an inert gas atmosphere at a predetermined temperature. Claims 7 to 9 Either One paragraph Described in Electroless It is a plating device. As a result, an inert gas is introduced into a space between the material to be processed held by the holding part during the plating process and the head part covering the upper surface of the material to be processed, and this space is filled with an inert gas atmosphere at a predetermined temperature. In this way, the surface of the plating solution comes into contact with the air, oxygen in the air is taken into the plating solution, the amount of dissolved oxygen in the plating solution increases, and the oxidizing action of the reducing agent is suppressed to prevent plating. It is possible to prevent precipitation from becoming difficult, and at the same time, it is possible to prevent the temperature of the plating solution from decreasing during plating. In the case of a reducing agent that easily decomposes (for example, DMAB, GOA), it is possible to extend the life of the liquid by preventing contact with air. This inert gas is, for example, N ₂ The temperature of the gas is, for example, about 60 to 70 ° C., preferably about 65 to 70 ° C. when the temperature of the plating solution is 70 ° C.
[0026]
Claim 11 The invention according to claim 2, further comprising a cleaning liquid introduction section for cleaning by flowing a cleaning liquid into the plating liquid holding tank and the plating liquid supply nozzle. 6 to 10 Either One paragraph Described in Electroless It is a plating device. Thereby, the deposit | attachment produced | generated on the wall surface of the plating solution holding tank or the plating solution supply nozzle can be removed periodically or at an arbitrary time. Examples of the cleaning liquid include pure water and HNO. ₃ , Cleaning chemicals such as aqua regia or HF.
[0027]
Contract Claim 12 The invention described in The peripheral edge of the plate was sealed with a seal ring and held with the surface to be plated facing upward, and a plating tank surrounded by the seal ring and opened upward was formed on the surface to be plated The back side of the workpiece , Consisting of hot water, alcohol or organic solution, at the same temperature as the plating solution below Treated by contact with heated fluid Material On the surface to be plated while heating Heated to a predetermined temperature in the formed plating tank Plating is performed by supplying a predetermined amount of plating solution. Electroless It is a plating method.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of copper wiring formation in a semiconductor device in the order of steps. First, as shown in FIG. 1A, SiO is formed on a conductive layer 1a on a semiconductor substrate 1 on which a semiconductor element is formed. ₂ An insulating film 2 is deposited, and a contact hole 3 and a wiring groove 4 are formed in the insulating film 2 by, for example, lithography / etching technique. A copper seed layer 6 as a power feeding layer for electrolytic plating is formed by sputtering or the like.
[0029]
Then, as shown in FIG. 1B, the surface of the semiconductor substrate W is plated with copper so that the contact holes 3 and the grooves 4 of the semiconductor substrate W are filled with copper, and a copper layer is formed on the insulating film 2. 7 is deposited. Thereafter, the copper layer 7 on the insulating film 2 is removed by chemical mechanical polishing (CMP), and the surface of the copper layer 7 filled in the contact hole 3 and the wiring groove 4 and the surface of the insulating film 2 Are almost coplanar. Thereby, as shown in FIG. 1C, a wiring 8 composed of the copper seed layer 6 and the copper layer 7 is formed inside the insulating film 2. Next, for example, electroless Ni—B plating is applied to the surface of the substrate W, and a protective film (plating film) 9 made of a Ni—B alloy film is formed on the exposed surface of the wiring 8 as shown in FIG. Is selectively formed to protect the wiring 8.
[0030]
2 and 3 show an electroless plating apparatus according to an embodiment of the present invention. This electroless plating apparatus is used, for example, for forming the barrier layer 5 in FIG. 1, reinforcing the copper seed layer 6, depositing the copper layer 7, and further forming a protective film (plating film) 9.
[0031]
The electroless plating apparatus 10 includes a substrate holding unit 12 that holds a substrate (material to be processed) W such as a semiconductor wafer with the surface (surface to be plated) of the substrate W facing upward (face-up). The substrate holding unit 12 includes a processing tank 14 having a heating fluid holding unit 40 for holding a heating fluid for heating the substrate W and a substrate pressing unit 16 surrounding the processing tank 14 as described below. The substrate pressing portion 16 is integrally connected with an extending portion 18 that extends upward from the processing tank 14, and a seal ring 20 is provided below the inner peripheral edge of the extending portion 18. Protrusively installed.
[0032]
The processing tank 14 is connected to the upper end of a main shaft 24 that rotates via a belt 23 as the motor 22 is driven, and a step 14 a along the size of the substrate W is provided on the upper surface. On the other hand, the substrate pressing portion 16 is connected to the upper end of a rod 28 erected on the periphery of a base 26 that surrounds the main shaft 24. Further, a cylinder 30 is disposed between the base 26 and a flange 24 a provided on the main shaft 24, and the substrate pressing portion 16 moves up and down relatively with respect to the processing tank 14 as the cylinder 30 operates. It has become. Further, the base 26 is provided with a push-up pin 32 that protrudes upward and reaches the lower side of the extending portion 18 of the substrate pressing portion 16. A through hole 14b penetrating therethrough is provided.
[0033]
Thereby, in a state where the substrate pressing portion 16 is relatively raised with respect to the processing tank 14, the substrate W is inserted therein, and the substrate W is placed and held on the upper end of the push-up pin 32, In this state, the substrate pressing portion 16 is lowered relative to the processing tank 14 so that the substrate W is positioned in the step 14a on the upper surface of the processing tank 14, and further lowered, whereby the seal ring 20 is moved to the substrate W. The substrate W is held in pressure contact with the outer peripheral edge of the upper surface of the substrate, thereby holding the substrate W, thereby forming a plating tank 34 surrounded by the upper surface of the substrate W and the seal ring 20 and opened upward. The holding of the substrate W is released by the reverse operation. Further, as the motor 22 is driven, the processing tank 14 and the substrate pressing unit 16 are integrally rotated while the substrate W is held by the substrate holding unit 12.
[0034]
A heating fluid holding unit 40 that holds a heating fluid such as warm water, alcohol, or an organic solution, and heats the substrate W by bringing the back surface of the substrate W into contact with the heating fluid is provided on the upper surface of the processing tank 14. That is, the heating fluid holding unit 40 FIG. As shown in FIG. 5, the recess 42 is formed in a circular shape along the shape of the substrate W continuously from the step 14a, and a plurality of flow channel grooves 44 that are formed deeper than the recess 42 and extend radially. The flow channel 44 reaches the outer peripheral portion of the processing tank 14 at the same depth. Each channel groove 44 communicates with a fluid passage 24b provided inside the main shaft 24. Further, the fluid passage 24b is, for example, a pure water supply source when heated pure water is used as a heating fluid. Is connected to a fluid supply pipe 48 having a pure water heating section 46 for heating pure water to the same temperature as the plating temperature, for example, 60 ° C.
[0035]
As a result, the heating fluid (hot water) supplied from the pure water supply source and heated by the pure water heating unit 46 passes through the fluid passage 24 b and flows into the heating fluid holding unit 40, and mainly enters the flow channel groove 44. After flowing along, it flows out of the processing tank 14.
[0036]
The heating fluid that has flowed into the heating fluid holding unit 40 in this way contacts the back surface of the substrate W held by the substrate holding unit 12 and heats the substrate W, whereby the heating fluid is transferred to the substrate. By following the irregularities on the back surface of W and making contact with the entire surface, increasing the contact area to efficiently conduct heat to the substrate W, and using a heating fluid such as hot water having a large heat capacity as a heat source, the substrate W can be heated more uniformly in a short time. For example, by bringing warm water controlled to a temperature of 60 ° C. into contact with the back surface of the semiconductor wafer, the semiconductor wafer can be heated to a surface temperature of 60 ° C. in about 2 to 3 seconds. And since the whole board | substrate W is not immersed in a plating solution, management of a plating solution becomes easy.
[0037]
Furthermore, in this example, the heater 50 is built in the processing tank 14, and the heating fluid flowing in the heating fluid holding unit 40 is heated by the heater 50, so that the temperature of the heating fluid can be prevented from gradually decreasing. It is like that.
[0038]
Around the substrate pressing portion 16, there is disposed a scattering prevention cover 52 that prevents the heated fluid from scattering and collects the heated fluid and discharges it from the drain 52a. Further, a pair of lids 58 that are positioned above the scattering prevention cover 52 and that can be opened and closed via a motor 56 and that cover the surface of the substrate W held by the substrate holding unit 12 and form a space close to hermetic sealing. Has been placed. The lid body 58 may be constituted by a single plate, for example.
[0039]
Thus, the lid 58 is closed during plating and the substrate W is positioned in a space close to hermetic sealing, so that heat from the substrate W is prevented by the lid 58 and the temperature of the substrate W during plating is more uniform. In addition, when the substrate W is moved up and down while being held by the substrate holding portion 12, it is possible to prevent the lid 58 from interfering with the substrate holding portion 12 by opening the lid 58. .
[0040]
Further, a plating solution (electroless plating solution) 60 heated to a predetermined temperature, for example, 60 ° C., is placed in the plating tank 34 formed by the upper surface of the substrate W and the seal ring 20, located above the substrate holding unit 12. A plating solution supply unit 62 for supplying the liquid is disposed. The plating solution supply unit 62 has a swingable arm 64, and uniformly sprays the plating solution 60 toward the substrate W held by the substrate holding unit 12 from an injection nozzle 66 provided at the tip of the arm 64. It is like that. The temperature of this plating solution is, for example, about 25 to 90 ° C, preferably about 55 to 85 ° C, and more preferably about 60 to 80 ° C.
[0041]
Although not shown, a plating solution recovery nozzle that is positioned above the substrate holding unit 12 and sucks and recovers the plating solution in the plating tank 34 and can freely move up and down, and the surface of the substrate W after plating. A cleaning nozzle for supplying a cleaning liquid such as ultrapure water is disposed.
[0042]
In the electroless plating apparatus according to this embodiment, the substrate W is first inserted into the substrate pressing portion 16 in a state where the substrate pressing portion 16 is relatively raised with respect to the processing tank 14, and It is placed and held on the raising pin 32. At this time, the lid 58 is in an open position. On the other hand, a heating fluid such as warm water heated to the same temperature as the plating solution 60, for example, 60 ° C., is introduced into the heating fluid holding unit 40 of the processing tank 14, and is allowed to overflow through the flow channel groove 44.
[0043]
In this state, the substrate pressing portion 16 is lowered relative to the processing bath 14, the substrate W is positioned in the step 14a on the upper surface of the processing bath 14, and further lowered, whereby the seal ring 20 is moved to the substrate W. The substrate W is held in pressure contact with the outer peripheral edge of the upper surface to hold the substrate W, thereby forming a plating tank 34 surrounded by the upper surface of the substrate W and the seal ring 20 and opened upward. At the same time, the back surface of the substrate W is brought into contact with the heating fluid introduced into the heating fluid holding unit 40 of the processing tank 14.
[0044]
Then, when the substrate W is heated by the heating fluid and reaches the same temperature as the heating fluid, for example, 60 ° C., the plating solution 60 heated to a predetermined temperature, for example, 60 ° C., from the spray nozzle 66 of the plating solution supply unit 62. Is injected into a plating tank 34 surrounded by the seal ring 20 on the upper surface of the substrate W (for example, about 100 cc to 200 cc for a 200 mm diameter wafer). Since the heating fluid supply timing can be adjusted to match the plating solution injection timing, Substrate holder 12 The substrate surface is not dried between the time when the substrate is placed and the plating solution is injected.
[0045]
Then, the lid 58 is closed to prevent heat dissipation from the surface of the substrate W, and the heating fluid introduced into the heating fluid holding unit 40 is heated by the heater 50 as necessary, and the temperature of the heating fluid is reduced. Prevents lowering during plating. Thereby, the substrate W is maintained at the temperature of the heating fluid over the entire surface, and a plating film having a uniform thickness grows. Moreover, since the outer peripheral edge of the substrate W is also immersed in the heating fluid, the temperature of the outer peripheral edge of the substrate does not decrease. At this time, for example, the substrate W can be rotated to make the hydrogen density and dissolved oxygen concentration of the surface to be plated uniform.
[0046]
After the plating process is completed, the introduction of the heating fluid into the heating fluid holding unit 40 is stopped, and the plating solution in the plating tank 34 surrounded by the seal ring 20 on the upper surface of the substrate W is discharged from the introduction side. Remove by suction. Then, while rotating the substrate W, a cleaning liquid is sprayed from a cleaning liquid nozzle (not shown) toward the surface to be plated of the substrate W, and the surface to be plated is cooled and diluted and cleaned at the same time. Stop.
[0047]
Then, the substrate pressing portion 16 is raised relative to the processing tank 14, the substrate W is lifted by the push-up pin 32, and the holding of the substrate W is released. Transport to process.
[0048]
FIG. 4 shows the overall configuration of a plating apparatus that performs a series of plating processes by the electroless plating apparatus 10. The plating apparatus includes a pair of electroless plating apparatuses 10 and a load / unload unit 70, such as a catalyst process for applying a Pd catalyst and an oxide film removing process for removing an oxide film attached to the exposed wiring surface. It has a pre-plating processing device 72 that performs processing, a rough-cleaning temporary placement unit 74, and a post-cleaning device 76, and further transports the substrate W between the load / unload unit 70, the post-cleaning device 76, and the temporary placement unit 74. And a second transport device 78b for transporting the substrate W between the electroless plating device 10, the pre-plating processing device 72, and the temporary placement unit 74.
[0049]
Next, a series of plating processes by the plating apparatus configured as described above will be described. First, the substrate W held on the load / unload unit 70 is taken out by the first transfer device 78 a and placed on the temporary placement unit 74. The second transport device 78b transports this to the plating pretreatment device 72, where PdCl ₂ A pre-plating process such as a catalyst applying process using a catalyst such as a liquid or an oxide film removing process for removing an oxide film adhering to the exposed wiring surface is performed, followed by rinsing.
[0050]
The second transfer device 78b further carries the substrate W to the electroless plating apparatus 10, and performs an electroless plating process using a predetermined reducing agent and a predetermined plating solution. Next, the substrate after plating is taken out from the electroless plating apparatus 10 by the second transfer device 78 b and is carried to the temporary placement portion 74. In the temporary placement section 74, the substrate is roughly cleaned. Then, the first transport device 78 a transports the substrate to the post-cleaning device 76, and after that, the cleaning device 76 performs finishing cleaning with a pencil sponge and drying by spin drying, and returns to the load / unload unit 70. The substrate is later transferred to a plating apparatus or an oxide film forming apparatus.
[0051]
FIG. 5 shows the overall configuration of a plating apparatus that performs a series of plating processes (lid plating processes) for forming the protective film 9 shown in FIG. The plating apparatus includes a load / unload section 80, a pretreatment section 82, a Pd adhesion section 84, a plating pretreatment section 86, an electroless plating apparatus 10, and a cleaning / drying treatment section 88. A transport device 92 is provided which can travel along the path and transfer substrates between them.
[0052]
Next, a series of plating processes (lid plating process) performed by the plating apparatus configured as described above will be described. First, the substrate W held by the load / unload unit 80 is taken out by the transfer device 92 and transferred to the pretreatment unit 82, where the substrate is subjected to pretreatment for cleaning the substrate surface again, for example. Then, Pd is adhered to the surface of the copper layer 7 (see FIG. 1) by the Pd adhesion portion 84 to activate the exposed surface of the copper layer 7, and then the plating pretreatment portion 86 performs pretreatment for plating such as neutralization. Apply processing. Next, it conveys to the electroless-plating apparatus 10, and performs the selective electroless-plating by Co-WP, for example on the surface of the activated copper layer 7, Thereby, FIG.1 (d) is carried out. As shown, the exposed surface of the copper layer 7 is protected by a Co—WP film (protective film) 9. Examples of the electroless plating solution include a cobalt salt and a tungsten salt to which a reducing agent, a complexing agent, a pH buffering agent, and a pH adjusting agent are added.
[0053]
The surface exposed after polishing is subjected to, for example, electroless Ni—B plating, and a protective film (plating film) 9 made of a Ni—B alloy film is selectively formed on the surface exposed to the outside of the wiring 8. Thus, the wiring 8 may be protected. The thickness of the protective film 9 is about 0.1 to 500 nm, preferably about 1 to 200 nm, and more preferably about 10 to 100 nm.
[0054]
The electroless Ni-B plating solution for forming the protective film 9 contains, for example, nickel ions, nickel ion complexing agents, alkylamine borane or borohydride compounds as nickel ion reducing agents, and is used for pH adjustment. What adjusted pH to 5-12 using TMAH (tetramethylammonium hydroxide) is used.
[0055]
Next, the substrate W after the lid plating process is transported to the cleaning / drying processing unit 88 to perform cleaning / drying processing, and the substrate W after the cleaning / drying is transferred to the cassette of the loading / unloading unit 80 by the transporting device 92. Return to.
In this example, the exposed surface of the copper layer 7 activated by depositing Pd is selected by a Co—WP film before the Co—WP electroless plating process is performed as the lid plating process. Although an example in which coating is performed is shown, it is needless to say that the present invention is not limited to this.
[0056]
FIG. 6 shows an electroless plating apparatus according to another embodiment of the present invention. The electroless plating apparatus 10c includes a disc-shaped lid 58a that can be moved up and down to cover the surface of the substrate W held by the substrate holder 12 so as to be freely opened and closed, and the lid 58a and the plating solution supply unit 62 are provided. A heater 59 that is integrated and surrounded by the substrate W and the lid 58a and that keeps the thermal insulation space near the temperature of the plating solution is built in the lid 58a. Other configurations are the same as those shown in FIGS. According to this example, heat dissipation from the surface of the plating solution supplied onto the surface to be plated of the substrate W can be suppressed. Note that the processing tank 14 may also include a heater 50 so that it is heated from above and below.
[0057]
FIG. 7 shows an electroless plating apparatus according to still another embodiment of the present invention. The electroless plating apparatus 10 a includes a substrate holding unit 100 that holds a substrate (material to be processed) W with the surface (surface to be plated) of the substrate W facing upward (face-up), and a lower portion of the substrate holding unit 100. It has the processing tank 102 arranged. The substrate holding part 100 has a housing 104 having a holding claw 104a projecting inwardly at the lower end and mounting and holding the outer peripheral edge of the substrate W, and a substrate having a cylindrical shape and a sealing claw 106a projecting inwardly at the lower end. The seal ring 108 is attached to the lower surface of the seal claw 106a so as to protrude downward. Further, the substrate pressing portion 106 is disposed inside the housing 104 and moves up and down relatively with respect to the housing 104 in accordance with the operation of the cylinder 110 attached to the housing 104.
[0058]
Thus, with the substrate pressing portion 106 raised relative to the housing 104, the substrate W is inserted therein, and the substrate W is placed and held by the holding claws 104a of the housing 104. By lowering the substrate pressing portion 106 relative to the housing 104, the seal ring 108 is brought into pressure contact with the outer peripheral edge portion of the upper surface of the substrate W, and the substrate W is sealed and held thereby. A plating tank 112 surrounded by the upper surface of W and the substrate pressing portion 106 and opened upward is formed. The holding of the substrate W is released by the reverse operation.
[0059]
The substrate holding unit 100 is connected to a motor 114 via the housing 104, and the motor 114 is fixed to the free end of the arm 116. Further, the arm 116 is attached to a vertical moving plate 120 that moves up and down as the motor 118 is driven, and tilts in the vertical direction as the tilting motor 121 is driven. As a result, the substrate holder 100 can rotate, move up and down, and tilt, and can perform these combined operations.
[0060]
On the upper surface of the processing tank 102, a heating fluid holding unit 122 is provided that is formed of a recess having an inner diameter larger than that of the substrate W and holds the heating fluid such as hot water to heat the substrate W. The heating fluid holding unit 122 is surrounded by the overflow weir 124, a heating fluid discharge path 126 is formed outside the overflow weir 124, and a drain 128 is provided in the heating fluid discharge path 126. Furthermore, when using pure water heated as a heating fluid, for example, the heating fluid holding unit 122 includes a pure water heating unit 46 that extends from a pure water supply source and heats pure water to the same plating temperature as, for example, 60 ° C. It is connected to a heating fluid supply pipe 48 interposed in the middle.
[0061]
As a result, the heating fluid (hot water) supplied from the pure water supply source and heated by the pure water heating unit 46 flows into the heating fluid holding unit 122 and overflows the overflow weir 124 to the outside of the processing tank 102. It comes to leak.
[0062]
Further, on the side of the substrate holding unit 100, a plating solution (electroless plating solution) 60 heated to a predetermined temperature, for example, 60 ° C. in a plating tank 112 formed by the upper surface of the substrate W and the substrate pressing unit 106. Is disposed. The plating solution supply unit 130 has an injection nozzle 132 that injects a plating solution at the tip.
[0063]
According to this embodiment, the substrate holding unit 100 holding the substrate W is lowered as described above, and the back surface of the substrate W is brought into contact with the heating fluid held by the heating fluid holding unit 122 to heat the substrate W. When the substrate W reaches the plating temperature, the plating solution at a predetermined temperature is injected from the plating solution supply unit 130 into the plating tank 112 formed by the upper surface of the substrate W and the substrate pressing unit 106. I do.
[0064]
Here, according to this example, the back surface of the substrate W is brought into contact with the heating fluid in a state where the substrate W held by the substrate holding unit 100 is inclined with respect to the water surface of the heating fluid in the processing tank 102, and thereafter By returning the substrate W horizontally, it is possible to prevent bubbles from remaining on the back surface of the substrate W. In addition, by inclining the substrate W after the end of plating, the electroless plating solution on the surface to be plated of the substrate W can be easily collected and discharged at one place.
[0065]
FIG. 8 shows an electroless plating apparatus according to still another embodiment of the present invention. The electroless plating apparatus 10b is different from the electroless plating apparatus 10a shown in FIG. 7 as follows. That is, the housing 104 is extended downward, and the belt 146 is stretched between the driven roller 140 attached to the downwardly extending portion of the housing 104 and the driving roller 144 attached to the motor 142, and the upper and lower sides are interposed via the motor 148. The motor 142 is fixed to a flange 152 attached to a moving vertical moving plate 150 so that the substrate holder 100 rotates and moves up and down.
[0066]
Further, a heating fluid supply passage 102a and a heating fluid discharge passage 102b are provided inside the processing tank 102, and the periphery of the processing tank 102 is surrounded by a scattering prevention cover 154 having a drain 154a for discharging a plating solution. Further, the plating solution supply unit 156 extends vertically on the sides of the anti-scattering cover 154, bends at a right angle, reaches a position just above the center of the substrate holding unit 100, and is attached to the tip of the injection nozzle downward. A plating solution is sprayed from 158 toward the upper surface (surface to be plated) of the substrate W. Other configurations are the same as those shown in FIG.
[0067]
According to this example, the rotation and vertical movement mechanism of the substrate holding unit 100 is disposed below the housing 104, so that the upper side of the substrate holding unit 100 is opened, and the plating solution supply unit 156 is placed above the substrate holding unit 100. Accordingly, the plating solution can be easily supplied.
[0068]
9 and 10 show an electroless plating apparatus according to still another embodiment of the present invention. The electroless plating apparatus 10d includes a substrate holding unit 200 that holds a substrate (material to be processed) W with the surface (surface to be plated) of the substrate W facing upward (face up). The substrate holding unit 200 includes a processing tank 202 having a heating fluid holding unit 216 for holding a heating fluid for heating the substrate W and a cylindrical housing 204 surrounding the processing tank 202 as described below. A hollow disk-like support plate 206 is fixed to the upper end of the housing 204, and a seal ring 208 is attached to the inner peripheral surface of the support plate 206 so as to protrude downward.
[0069]
A ring-shaped substrate stage 210 that supports the peripheral portion of the substrate W and a guide ring 212 that is located on the outer peripheral portion of the substrate W and prevents the displacement of the substrate W are attached to the upper surface of the processing tank 202. The processing tank 202 is movable up and down relatively with respect to the housing 204, and the substrate W is inserted into the housing 204 with the processing tank 202 lowered relative to the housing 204. The substrate W is placed on and held on the upper surface of the substrate stage 210, and in this state, the processing tank 202 is raised relative to the housing 204, whereby the seal ring 208 is placed on the outer peripheral edge of the upper surface of the substrate W. The substrate W is held by pressure contact and sealed, thereby forming a plating bath 214 surrounded by the upper surface of the substrate W and the seal ring 208 and opened upward. The holding of the substrate W is released by the reverse operation. Further, as the motor (not shown) is driven, the processing tank 202 and the housing 204 rotate integrally while holding the substrate W by the substrate holding unit 200.
[0070]
A heating fluid holding unit 216 that holds a heating fluid such as warm water, alcohol, or an organic solution and heats the substrate W by bringing the heating fluid into contact with the back surface of the substrate W is provided on the upper surface of the processing tank 202. The heating fluid holding unit 216 is configured by a trumpet-shaped channel that opens upward, and the heating fluid holding unit 216 includes, for example, a pure water heating unit that heats pure water to 60 ° C., as described above. It is connected to a fluid supply pipe interposed in the middle. The heated fluid that has overflowed the heated fluid holding portion 216 flows out between the processing tank 202 and the housing 204 and flows out to the outside. As described above, a scattering prevention cover (not shown) for preventing the heating fluid from scattering is disposed around the housing 204.
[0071]
A plating solution (electroless plating solution) 60 heated to a predetermined temperature, for example, 60 ° C., is supplied into the plating tank 214 formed by the upper surface of the substrate W and the seal ring 208 located above the substrate holding unit 200. A plating solution supply unit 220 is disposed. The plating solution supply unit 220 has a swing arm 222 that can move up and down and swing, and is formed in a disk shape that is formed at the free end of the swing arm 222 so as to substantially cover the opening of the plating tank 214. The head portion 224 is attached. Then, as the swing arm 222 swings, the head portion 224 moves between a position covering the upper portion of the substrate holding portion 200 and a retracted position as shown in FIG. In the processing, the head unit 224 is positioned at a predetermined position covering the upper side of the substrate W held by the substrate holding unit 200, and otherwise, the head unit 224 is retracted to the retracted position, so that the head unit 224 is retracted to the substrate W. It is designed to prevent obstructing the conveyance and the like.
[0072]
A plating solution supply nozzle 226 that is located substantially at the center of the head portion 224 and opens downward has a volume that holds a predetermined amount of plating solution for one plating operation, located above the plating solution supply nozzle 226. A plating solution holding tank 228 is disposed, and the plating solution supply nozzle 226 and the plating solution holding tank 228 are connected by a plating solution pipe 230. A plating solution supply pipe 232 and a plating solution discharge pipe 234 are connected to the plating solution holding tank 228, respectively. Further, an opening / closing valve (not shown) is connected to the plating solution pipe 230, the plating solution supply pipe 232, and the plating solution discharge pipe 234. Z)).
[0073]
Thereby, at the time of non-plating, the opening / closing valve of the plating solution pipe 230 is closed, the opening / closing valve of the plating solution supply pipe 232 and the plating solution discharge pipe 234 is opened, and the plating solution in the plating solution holding tank 228 is circulated. A predetermined amount of plating solution is always held at a constant temperature inside the plating solution holding tank 228. Then, the opening / closing valve of the plating solution pipe 230 is opened, and the opening / closing valves of the plating solution supply pipe 232 and the plating solution discharge pipe 234 are closed, so that a predetermined amount of a predetermined amount held in the plating solution holding tank 228 is maintained. The plating solution can be supplied instantaneously (for example, for 1 to 5 seconds) from the plating solution supply nozzle 226 into the plating tank 214 formed by the upper surface of the substrate W and the seal ring 208 by its own weight.
[0074]
Located above the plating solution supply nozzle 226 is, for example, a plating pretreatment solution holding tank 236 that holds a plating pretreatment solution such as a washing solution for performing plating pretreatment washing or a catalyst application solution for performing a catalyst application treatment. The plating pretreatment liquid holding tank 236 and the plating liquid supply nozzle 226 are connected by a plating pretreatment liquid pipe 238. Furthermore, a plating pretreatment liquid supply pipe 240 and a plating pretreatment liquid discharge pipe 242 are connected to the plating pretreatment liquid holding tank 236, respectively, and a plating pretreatment liquid pipe 238, a plating pretreatment liquid supply pipe 240, and a plating pretreatment. An open / close valve (not shown) is interposed in the liquid discharge pipe 242.
[0075]
Thus, as in the case of the above-described plating solution, during the non-plating pretreatment, a predetermined amount of the plating pretreatment solution is always held at a constant temperature in the plating pretreatment solution holding tank 236, and the plating pretreatment is performed. Sometimes, the plating pretreatment liquid held inside the plating pretreatment liquid holding tank 236 via the opening / closing valve is instantaneously (for example, 1 to 5 seconds) from the plating liquid supply nozzle 226 to the upper surface of the substrate W. It can be supplied into the plating tank 214 formed by the seal ring 208. In this example, the plating solution supply nozzle 226 also serves as a nozzle for supplying a plating pretreatment solution, but may be provided separately. When performing a plurality of plating pretreatments, a plurality of plating pretreatment liquid holding tanks are provided, and the plating pretreatment liquids held in the respective plating pretreatment liquid holding tanks are sequentially supplied to the surface to be plated of the substrate W. Of course, you may do it.
[0076]
By comprising in this way, in the state which hold | maintained the board | substrate W with the board | substrate holding | maintenance part 200, pre-processing and plating processes, such as washing | cleaning and catalyst provision, can be continuously performed in 1 tank. As a cleaning solution for pretreatment cleaning of this plating, H ₂ SO ₄ , HF, HCl, NH ₃ , DMAB (dimethylamine borane), oxalic acid, or the like may be used as a catalyst application liquid for performing the catalyst application process. ₄ And PdCl ₂ Etc.
[0077]
The head unit 224 includes a pure water supply nozzle 250 that supplies pure water to the upper surface (surface to be plated) of the substrate W held by the substrate holding unit 200. Thus, by supplying pure water from the pure water supply nozzle 250 to the surface of the substrate after the plating process, the plating process and the rinsing with the pure water after the plating process can be continuously performed in one tank. It has become.
[0078]
In the head part 224, a plating solution recovery nozzle 252 that recovers the plating solution supplied to the surface to be plated of the substrate W held by the substrate holding unit 200 and the surface to be plated of the substrate W held by the substrate holding unit 200 are supplied. And a plating pretreatment liquid recovery nozzle 254 for recovering the plated pretreatment liquid. As a result, the plating solution is recovered from the plating solution recovery nozzle 252 and reused, and further, if necessary, the plating pretreatment solution is recovered from the plating pretreatment solution recovery nozzle 254 and reused. Thus, the usage amount of the plating solution and the plating pretreatment solution can be reduced, and the running cost can be reduced.
[0079]
The plating solution supply nozzle 226 includes, for example, N ₂ An inert gas introduction path (inert gas introduction section) 256 for introducing a heated inert gas such as a gas is connected, and the heated inert gas introduced into the plating solution supply nozzle 226 from the inert gas introduction path 256 is connected. The active gas is jetted toward the substrate W held by the substrate holding unit 200 after purging the inside of the plating solution supply nozzle 226. As a result, an inert gas is introduced into the space between the substrate W held by the substrate holder 200 and the head portion 224 positioned so as to cover the upper surface of the substrate W, and this space is inactivated at a predetermined temperature. By maintaining the gas atmosphere, the surface of the plating solution comes into contact with air, oxygen in the air is taken into the plating solution, the amount of dissolved oxygen in the plating solution increases, and the oxidizing agent of the reducing agent is suppressed. Thus, it is possible to prevent the plating from becoming difficult to deposit, and at the same time, it is possible to prevent the temperature of the plating solution from being lowered during the plating. Alternatively, before the plating solution is injected, the portion surrounded by the head portion 224 and the substrate W is kept at a predetermined temperature in an inert gas atmosphere, thereby preventing air contamination and a decrease in the solution temperature when the plating solution is injected. it can. This N ₂ The temperature of the inert gas such as gas is, for example, 60 to 70 ° C. (plating solution temperature−10 ° C. to plating solution temperature), preferably 65 to 70 ° C. (plating solution) when the temperature of the plating solution is 70 ° C. The temperature is about −5 ° C. to the temperature of the plating solution.
[0080]
A cleaning liquid introduction path (cleaning liquid introduction part) 260a is connected to the plating liquid holding tank 228, and a cleaning liquid introduction path (cleaning liquid introduction part) 260b is connected to the plating pretreatment liquid holding tank 236, respectively. As a result, the cleaning liquid introduced into the plating liquid holding tank 228 from the cleaning liquid introduction path 260a sequentially flows through the inside of the plating liquid pipe 230 and the plating liquid supply nozzle 226, and from the cleaning liquid introduction path 260b, the plating pretreatment liquid. The cleaning liquid introduced into the holding tank 236 flows in this order, the plating pretreatment liquid pipe 238 and the plating liquid supply nozzle 226 in order, and the deposits generated on these inner walls can be cleaned and removed. ing. This cleaning can be performed periodically or at any time. Examples of the cleaning liquid include pure water and HNO. ₃ , Cleaning chemicals such as aqua regia or HF.
[0081]
In this example, a heater 262 that is surrounded by the substrate W held by the substrate holding part 200 and the head part 224 and that keeps the heat insulation space near the temperature of the plating solution is built in the head part 224.
[0082]
The plating process by the electroless plating apparatus of this embodiment will be described with reference to FIG. First, in a state where the processing tank 202 is lowered relative to the housing 204, the substrate W is inserted into the housing 204 and placed and held on the substrate stage 210. At this time, the head unit 224 is in the retracted position. In this state, the processing tank 202 is raised relative to the housing 204, the seal ring 208 is pressed against the outer peripheral edge of the upper surface of the substrate W, and the substrate W is sealed to thereby hold the substrate W. A plating tank 214 surrounded by the upper surface of the substrate W and the seal ring 208 and opened upward is formed.
[0083]
Next, the head unit 224 is moved to a position immediately above the substrate holding unit 200 and further lowered. In this state, a predetermined amount of the plating pretreatment liquid, such as a cleaning liquid or a catalyst application liquid, held in the plating pretreatment liquid holding tank 236, by its own weight, is used as a plating liquid supply nozzle 226 that also serves as the plating pretreatment liquid supply nozzle. Then, a pre-plating process is performed by instantaneously supplying to the surface to be plated of the substrate held by the substrate holding unit 200. After this pre-plating process is completed, the pre-plating process liquid remaining on the surface to be plated of the substrate W is recovered by the pre-plating process liquid recovery nozzle 254 and reused as necessary.
[0084]
Next, a heating fluid such as hot water heated to the same temperature as the plating solution 60, for example, 70 ° C., is introduced into the heating fluid holding unit 216 of the processing tank 202, and the back surface of the substrate W held by the substrate holding unit 200 is processed. The heated fluid introduced into the heated fluid holding part 216 of the tank 202 is brought into contact with the heated fluid to overflow. Then, when the substrate W is heated with the heating fluid and reaches the same temperature as the heating fluid, for example, 70 ° C., a certain amount held in the plating solution holding tank 228 (for example, about 100 to 200 cc for a 200 mm diameter wafer and a 300 mm diameter wafer). In this case, the plating solution at a constant temperature of about 200 to 400 cc is instantaneously supplied from the plating solution supply nozzle 226 to the surface to be plated held by the substrate holding unit 200 by its own weight to perform the plating process.
[0085]
During this plating process, a heated inert gas is introduced into the plating solution supply nozzle 226 from the inert gas introduction path 256, the inside of the plating solution supply nozzle 226 is purged with this inert gas, and the substrate holding unit 200. An inert gas is introduced into a space between the substrate W held in step S1 and the head portion 224 positioned so as to cover the upper surface of the substrate W, and the space is held in an inert gas atmosphere at a predetermined temperature.
[0086]
And if necessary, the plating solution is heated by the heater 262 to prevent the temperature of the plating solution from decreasing during plating. Thereby, the substrate W is maintained at the temperature of the heating fluid over the entire surface, and a plating film having a uniform thickness grows. Moreover, since the outer peripheral edge of the substrate W is also immersed in the heating fluid, the temperature of the outer peripheral edge of the substrate does not decrease. At this time, for example, the substrate W can be rotated so that hydrogen is separated from the surface to be plated and the dissolved oxygen concentration is made uniform.
[0087]
After the plating process is completed, the introduction of the heating fluid into the heating fluid holding unit 216 is stopped, discharged from the introduction side, and the plating solution in the plating tank 214 surrounded by the seal ring 208 on the upper surface of the substrate W is removed. It is recovered from the plating solution recovery nozzle 252 by negative pressure suction or the like and reused as necessary. Then, after the introduction of the inert gas from the inert gas introduction path 256 is stopped, pure water is sprayed from the pure water supply nozzle 250 toward the plating surface of the substrate W while rotating the substrate W, The electroless plating reaction is stopped by diluting and cleaning the plated surface at the same time. Thereafter, the substrate W is rotated at a high speed to drain the liquid.
[0088]
Then, after raising the head portion 224 and retracting it to the retracting portion, the processing tank 202 is lowered relative to the housing 204 to release the holding of the substrate W, and then after plating with a robot hand or the like. The substrate is transferred to the next process.
[0089]
According to the plating apparatus of this embodiment, each treatment such as pre-plating treatment, plating treatment, pure water rinsing, and liquid removal can be continuously performed in one tank. Thereby, while preventing the surface (to-be-plated surface) of the board | substrate W from being wet, ie, drying, while performing each process, the number of tanks can be reduced and installation space can be reduced. .
[0091]
【The invention's effect】
As described above, according to the present invention, temperature unevenness occurs in the surface to be treated of the material to be treated during the plating process, or the plating temperature is prevented from changing during the plating process. A plating film having a uniform thickness can be formed on the surface to be plated of the material to be plated so that the temperature becomes more uniform over the entire surface to be plated.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of forming a copper wiring by copper plating in the order of steps.
FIG. 2 is a cross-sectional view showing an electroless plating apparatus according to an embodiment of the present invention.
3 is a plan view of the treatment tank of FIG. 2. FIG.
4 is a plan layout view showing an example of a plating apparatus provided with the electroless plating apparatus shown in FIG. 2. FIG.
FIG. 5 is a plan layout view showing another example of a plating apparatus provided with the electroless plating apparatus shown in FIG.
FIG. 6 is a cross-sectional view showing another example of the electroless plating apparatus according to the embodiment of the present invention.
FIG. 7 is a cross-sectional view showing still another example of the electroless plating apparatus according to the embodiment of the present invention.
FIG. 8 is a cross-sectional view showing still another example of the electroless plating apparatus according to the embodiment of the present invention.
FIG. 9 is a cross-sectional view showing still another example of the electroless plating apparatus according to the embodiment of the present invention.
10 is a plan view of the electroless plating apparatus shown in FIG.
FIG. 11 is a flowchart showing a processing procedure when plating is performed by the electroless plating apparatus shown in FIG. 8;
[Explanation of symbols]
6 Copper seed layer
7 Copper layer
8 Wiring
9 Protective film
10, 10a, 10b, 10c, 10d Electroless plating equipment
12, 100, 200 substrate holder
14, 102, 202 Treatment tank
16, 106 Substrate pressing part
20, 108, 208 Seal ring
24 Spindle
34, 112, 214 Plating bath
40, 122, 216 Heating fluid holding part
42 Heating fluid holding part
44 Channel groove
50,262 Heater
52,152 Anti-scatter cover
58,58a lid
60 Plating solution
62,130,156 Plating solution supply unit
66, 132, 158 Injection nozzle
70 Load / Unload Club
72 Pretreatment equipment
74 Temporary placement
76 Post-cleaning equipment
80 Load / Unload Club
82 Pre-processing section
84 Pd adhesion part
86 Pre-processing section
88 Cleaning / drying processing section
104 Housing
104a Holding claw
106a Sealing claw
124 Overflow weir
204 housing
222 Swing arm
224 head
226 Plating solution supply nozzle
228 Plating solution holding tank
236 Pretreatment solution holding tank for plating
250 Pure water supply nozzle
252 Plating solution recovery nozzle
254 Pretreatment plating liquid recovery nozzle
256 Inert gas introduction path (inert gas introduction part)
260a, 260b Cleaning liquid introduction path (cleaning liquid introduction part)

Claims

Holding to form a plating tank which the workpiece in the upward outer periphery of the seal to the surface to be plated with the seal ring of the surface to be plated and hold, opens upward is surrounded by the seal ring on the surface to be plated And
A heating fluid that heats the material to be treated by bringing it into contact with the back surface of the material to be treated held by the holding unit, and is composed of warm water, alcohol, or an organic solution, and retains the heating fluid having the same temperature as the plating solution below. A heated fluid holding unit,
An electroless plating apparatus comprising: a plating solution supply unit configured to supply a plating solution heated to a predetermined temperature into the plating tank formed on the plating target surface of the material to be processed held by the holding unit. .

2. The electroless plating apparatus according to claim 1, further comprising a lid provided with a heater that covers the upper part of the plating tank so as to be openable and closable and prevents heat dissipation of the plating solution supplied into the plating tank .

The holding unit, an electroless plating apparatus according to claim 1 or 2, wherein it is configured to be movable vertically and rotate.

The holding unit, an electroless plating apparatus according to any one of claims 1 to 3, characterized in that it is constituted tilt freely.

The plating solution supply unit is movable up and down, and has a head unit that also functions as a lid that can move between a position covering the upper part of the plating tank and a side retracted position. The electroless plating apparatus according to any one of claims 1 to 4, further comprising a moving arm and a plating solution supply nozzle attached to the head portion.

The plating solution supply unit holds a predetermined amount of plating solution for one plating and supplies the plating solution by its own weight from the plating solution supply nozzle into the plating tank, and the plating solution holding tank. 6. The electroless plating apparatus according to claim 5 , further comprising a mechanism for maintaining the held plating solution at a predetermined temperature.

Said head portion, according to claim 5 or 6 further characterized in that is provided with a pre-plating treatment liquid holding tank for supplying the plating tank by its own weight and held the plating pretreatment solution plating pretreatment solution Electroless plating equipment.

Wherein the head portion, an electroless plating apparatus according to any one of claims 5 to 7, characterized in that is provided with a pure water supply nozzle for supplying pure water to the plating tank.

The electroless plating apparatus according to any one of claims 1 to 8 , further comprising a plating solution recovery nozzle that recovers the plating solution supplied into the plating tank .

An inert gas is introduced into a space between the material to be processed held by the holding part and the head part positioned so as to cover the upper part of the plating tank , and the space is brought to an inert gas atmosphere at a predetermined temperature The electroless plating apparatus according to any one of claims 7 to 9 , further comprising an inert gas introduction portion to be held.

The electroless plating apparatus according to any one of claims 6 to 10 , further comprising a cleaning liquid introduction section for cleaning by flowing a cleaning liquid into the plating liquid holding tank and the plating liquid supply nozzle.

The periphery of the surface to be plated is sealed with a seal ring, and the surface to be plated is held upward, and the back surface of the material to be treated is formed on the surface to be plated and is surrounded by the seal ring and opens upward. Heated to a predetermined temperature in the plating tank formed on the surface to be plated, which is made of hot water, alcohol or organic solution, and heated to the treatment material by contacting with the heating fluid having the same temperature as the plating solution An electroless plating method, wherein plating is performed by supplying a predetermined amount of plating solution.