JP3718297B2 - Thin film manufacturing method and thin film manufacturing apparatus - Google Patents

Thin film manufacturing method and thin film manufacturing apparatus Download PDF

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JP3718297B2
JP3718297B2 JP22939296A JP22939296A JP3718297B2 JP 3718297 B2 JP3718297 B2 JP 3718297B2 JP 22939296 A JP22939296 A JP 22939296A JP 22939296 A JP22939296 A JP 22939296A JP 3718297 B2 JP3718297 B2 JP 3718297B2
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thin film
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JPH1064849A (en
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仁志 神馬
瑞元 金
敦 関口
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アネルバ株式会社
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/56—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/28—Titanium compounds
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/34—Nitrides
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/4401—Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber
    • C23C16/4405—Cleaning of reactor or parts inside the reactor by using reactive gases
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
    • C23C16/46—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for heating the substrate

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  • Engineering & Computer Science (AREA)
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Description

【０００１】
【発明の属する技術分野】
本発明は、半導体デバイス、超伝導デバイス、各種電子部品、各種センサ等を構成する拡散防止膜、密着層膜、反射防止膜等として使用する窒化チタンを主成分とする薄膜の作製方法および作製装置に関する。
【０００２】
【従来の技術】
半導体デバイス、超伝導デバイス、各種電子部品、各種センサの拡散防止膜、密着層膜、反射防止膜等の作製は、基体の表面に対し、蒸着法、スパッタリング法、化学蒸着（ＣＶＤ）法、プラズマアシストＣＶＤ法等の種々の方法で成膜が試みられている。
【０００３】
近年、デバイスの集積化が進むにつれて、高アスペクト比の穴や溝への被覆性の良い成膜が求められている。例えば、半導体集積回路のコンタクト部作製技術として、配線用タングステン（Ｗ）と基体シリコン（Ｓｉ）との相互拡散を防止し、安定した電気的特性を得るためや、ロジック系集積回路用配線のＣｕが基体や絶縁層（ＳｉＯ2 ）中へ拡散してしまうことを防止する窒化チタンを主成分とする拡散防止膜を作製する必要性が生じている。さらに、半導体集積回路のスルーホール作製技術としてＡｌ−Ａｌ間の密着層が必要である。この密着層膜としても、やはり窒化チタンを主成分とする薄膜（以下「窒化チタン薄膜」という）が用いられ、高アスペクト比の穴の底部に良好な被覆性で成膜されることが求められている。
【０００４】
一方、上記窒化チタン薄膜を比較的良好な被覆性で作製する方法として注目されている技術の一つに有機金属化合物や有機金属錯体を原料として用いたＣＶＤ技術がある。例えばM.Eizenberg 等のAppl.Phys.Lett.65(19),7 November 1994.P.2416-2418 の中にその方法に関する記述がある。M.Eizenberg 等はテトラキスジメチルアミノチタン（ＴＤＭＡＴ）のみを原料として窒化チタン薄膜を、成膜圧力０．４５Torr（６０Ｐａ）、基体温度３８０〜４７０℃で作製している。彼等が作製した窒化チタン薄膜は、ラザフォード後方散乱法による分析では約２３％の酸素を含有し、またオージェ電子分光法では約２４％の酸素を含有することが報告されている。
【０００５】
窒化チタン薄膜における上記の酸素含有は、当該薄膜の堆積時に大気中で徐々に酸化されてしまうことによって生じる。一般的にテトラキスジアルキルアミノチタン（ＴＤＡＡＴ）を原料ガスとして用いたＣＶＤ法により作製した窒化チタン薄膜は、大気によって酸化され、高い濃度の酸素混入が生じる。酸素混入が生じると、電気的特性の観点では膜の抵抗値が増大することになる。このことは、窒化チタン薄膜を、信頼性の高い各種電子デバイスの製造に使用する際に重大な欠点となる。特に、窒化チタン薄膜は、酸化されて抵抗率が上昇するので、低抵抗の薄膜として使用することが不可能である。
【０００６】
そこで上記問題を解決するため、彼等は、作製した窒化チタン薄膜を大気に晒すことなく、その上にタングステン薄膜を連続して堆積させ、窒化チタン薄膜と大気の接触を遮断し、当該薄膜の酸化を防止している。この工程を行うことによって彼等は酸素含有量を１％に抑えることができた。
【０００７】
しかしながら、ＴＤＡＡＴを原料ガスとした熱ＣＶＤ法により作製された窒化チタン薄膜は、蒸着等の物理的方法により作製された膜に比べ、化学的には不安定な膜である。そのような不安定な膜の上に他の膜を堆積することによって大気を遮断して酸化を防止する方法では、化学的に不安定であるという窒化チタン薄膜の特性を根本的に解消することはできず、経時的な化学構造の変化等の長期的な経時変化により生ずる特性劣化は避けられない。このことから、ＴＤＡＡＴを用いた熱ＣＶＤ法による窒化チタン薄膜の作製は、被覆性等の点で優れているとの評価を受けつつも、作製される膜の電気特性の点で電子デバイスの信頼性を低下させる問題が生じてきた。
【０００８】
またR. L. Jackson 等のConference Proceedings ULSI MRS 1994P.223-P.237 によると、R. L. Jackson 等はテトラキスジエチルアミノチタン（ＴＤＥＡＴ）とアンモニアを原料として窒化チタン薄膜を成膜圧力１０Torr（１３３３Ｐａ）、基体温度３５０℃で作製している。彼等が作製した窒化チタン薄膜は、成膜後１日以上大気中に放置した場合でも抵抗値は１％程度に抑えることができる。しかしながら、穴径φ１．３６μｍ、アスペクト比３．４のコンタクトホールに対し、１０％未満のカバレッジしか得られていない。さらに成膜圧力が高いことによる空間反応によってダストの発生が生じる。
【０００９】
また、Gurtej S. Sandhu等の米国特許第５，２５４，４９９号によると、５〜１００Torrの範囲でＴｉＮを主成分とする薄膜を作製した結果、５Torr未満で作製したときと比較して密度の高い膜を得られる。しかし、前述と同様に、成膜圧力が高いことによる空間反応によってダストの発生が生じる。
【００１０】
また、上記のような化学的に不安定な膜をプラズマによって後処理を行い、安定化させる方法としてChin-Kun Wang 等の1995 DRY PROCESS SYMPOSIUM p129-133 に記述される方法がある。彼等によるとＴＤＭＡＴを用いてＴｉＮ膜を作製した後、Ｎ2 プラズマによる後処理を施している。この場合プラズマ密度が１０10個／ｃｍ3 より少ないため、後処理をする時間が長くなり、スループットを遅らせ、さらに極数ｎｍ程度の膜厚のみの改質だけしか実現することができない。
【００１１】
【発明が解決しようとする課題】
上記のごとく、ＴＤＡＡＴを原料とした熱ＣＶＤ法による窒化チタン薄膜の作製技術は、高アスペクト比の穴や溝への被覆性という点で比較的優れているが、作製される膜の電気特性の点で問題があった。また膜の電気特性を優先して成膜を行うと、被覆性やダスト発生の問題が生じる。さらに、通常のプラズマ密度が１０10個／ｃｍ3 に満たないプラズマ後処理を行った場合でも、スループットを遅らせたり改質する膜厚が極薄い膜でしか望めないという問題がある。
【００１２】
本発明の目的は、上記問題を解決することにあり、窒化チタンを主成分とする薄膜を、良好な被覆性を維持し、ダストの発生を抑え、膜の電気特性が良好であって経時的にも劣化せず化学的にも安定であり、短いスループットで作製できる薄膜作製方法および薄膜作製装置を提供することにある。
【００１３】
【課題を解決するための手段および作用】
本発明に係る薄膜作製方法は、上記目的を達成するため、次のように構成される。
【００１４】
第１の薄膜作製方法（請求項１に対応）は、気化したテトラキスジアルキルアミノチタンよりなる原料ガスを気体状態で加熱して化学反応させ、この化学反応によって基体上に窒化チタンを主成分とする薄膜を作製する薄膜作製方法であり、窒化チタンを主成分とする素薄膜を基体上に作製する第１の工程と、アンモニア、水素、またはこれらを混合してなる処理ガス、あるいはアンモニア、水素、窒素を混合してなる処理ガスの雰囲気下で電子密度が１０１０個／ｃｍ３ 以上の高密度プラズマを発生させ、活性化した処理ガスによって素薄膜を改質する第２の工程とからなることを特徴とする。
【００１５】
第２の薄膜作製方法（請求項２に対応）は、第１の薄膜作製方法において、第１の工程と第２の工程が異なる容器で行われ、これらの容器で、基体は搬送機構によって搬入・搬出されることを特徴とする。
【００１６】
第３の薄膜作製方法（請求項３に対応）は、第１の薄膜作製方法において、第１の工程と第２の工程が同じ容器で行われ、第１の工程と第２の工程の間に、基体を容器から取り出した状態で容器内のクリーニング工程が行われることを特徴とする。
【００１７】
第４の薄膜作製方法（請求項４に対応）は、上記の各薄膜作製方法において、好ましくは、第２の工程で高密度プラズマを発生させる際、２７〜１５００ＭＨｚの範囲に含まれる周波数の電力を供給する高周波電源を使用することを特徴とする。
【００１８】
第５の薄膜作製方法（請求項５に対応）は、上記の各薄膜作製方法において、好ましくは、第２の工程で高密度プラズマを発生させる際、高密度プラズマを安定させる安定化ガスを処理ガスと共に導入することを特徴とする。
【００１９】
第６の薄膜作製方法（請求項６に対応）は、上記の各薄膜作製方法において、好ましくは、第２の工程で高密度プラズマを発生させる際、内蔵アンテナ型高密度プラズマ源、ヘリコン波励起プラズマ源、ＥＣＲプラズマ源のうちいずれかを使用することを特徴とする。
【００２０】
第７の薄膜作製方法（請求項７に対応）は、第１の薄膜作製方法において、テトラキスジアルキルアミノチタン（ＴＤＡＡＴ）が、テトラキスジメチルアミノチタン（ＴＤＭＡＴ）またはテトラキスジエチルアミノチタン（ＴＤＥＡＴ）であることを特徴とする。
【００２１】
第８の薄膜作製方法（請求項８に対応）は、第３の薄膜作製方法において、クリーニング工程では、基体を大気に晒すことなく容器から同一真空雰囲気で一旦取り出し、容器内のクリーニング処理が行われることを特徴とする。
【００２２】
本発明に係る薄膜作製装置は、上記目的を達成するため、次のように構成される。
【００２３】
第１の薄膜作製装置（請求項９に対応）は、気密構造を有し内部に基体を保持する基体ホルダを備えた反応容器、この反応容器内にテトラキスジアルキルアミノチタンを導入する原料導入機構、反応容器内を真空に排気する排気機構を備え、窒化チタンを主成分とする素薄膜を基体上に作製する第１工程用機構と、気密構造を有し内部に基体を保持する基体ホルダを備えた処理容器、この処理容器に処理ガスを導入する処理ガス導入機構、処理容器内を真空に排気する排気機構、処理容器内に電子密度が１０10個／ｃｍ3 以上の高密度プラズマを発生させる高密度プラズマ発生機構を備え、活性化した処理ガスによって基体の素薄膜を改質する第２工程用機構と、反応容器と処理容器を同じ真空状態で連通可能にし、基体を大気に晒すことなく反応容器から処理容器に搬送する搬送機構と、を備えることを特徴とする。
【００２４】
第２の薄膜作製装置（請求項１０に対応）は、第１の薄膜作製装置において、好ましくは、高密度プラズマ発生機構は２７〜１５００ＭＨｚの範囲に含まれる周波数の電力を供給する高周波電源を含むことを特徴とする。
【００２５】
第３の薄膜作製装置（請求項１１に対応）は、第１の薄膜作製装置において、好ましくは、第２工程用機構は、高密度プラズマを安定させる安定化ガスを導入する安定化ガス導入機構を備えることを特徴とする。
【００２６】
第４の薄膜作製装置（請求項１２に対応）は、第１の薄膜作製装置において、好ましくは、第２工程用機構の高密度プラズマ発生機構は、内蔵アンテナ型高密度プラズマ源、ヘリコン波励起プラズマ源、ＥＣＲプラズマ源のうちいずれかを備えることを特徴とする。
【００２７】
第５の薄膜作製装置（請求項１３に対応）は、気密構造を有し内部に基体を保持する基体ホルダを備えた容器と、この容器内にテトラキスジアルキルアミノチタンを導入する原料導入機構と、容器に処理ガスを導入する処理ガス導入機構と、容器内を真空に排気する排気機構と、容器内に電子密度が１０10個／ｃｍ3 以上の高密度プラズマを発生させる高密度プラズマ発生機構と、容器内にプラズマを発生して容器内をクリーニングするクリーニング機構と、クリーニングの際に基体を容器の外に取り出す取出し機構を備え、原料導入機構から供給されるテトラキスジアルキルアミノチタンの原料ガスによって基体ホルダ上の基体の表面に窒化チタンを主成分とする素薄膜を作製し、その後取出し機構で基体を容器の外に取出した状態でクリーニング機構によって容器内をクリーニングし、その後、基体を再び基体ホルダの上に保持した状態で処理ガス導入機構によって供給される処理ガスで基体の素薄膜を改質したことを特徴とする。
【００２８】
第６の薄膜作製装置（請求項１４に対応）は、第５の薄膜作製装置において、好ましくは、高密度プラズマ発生機構は２７〜１５００ＭＨｚの範囲に含まれる周波数の電力を供給する高周波電源を含むことを特徴とする。
【００２９】
第７の薄膜作製装置（請求項１５に対応）は、第５の薄膜作製装置において、好ましくは、高密度プラズマを安定させる安定化ガスを導入する安定化ガス導入機構を備えることを特徴とする。
【００３０】
第８の薄膜作製装置（請求項１６に対応）は、第５の薄膜作製装置において、好ましくは、高密度プラズマ発生機構は、内蔵アンテナ型高密度プラズマ源、ヘリコン波励起プラズマ源、ＥＣＲプラズマ源のうちいずれかを備えることを特徴とする。
【００３１】
【発明の実施の形態】
以下に、本発明の好適な実施形態を添付図面に基づいて説明する。
【００３２】
図１は本発明の薄膜作製装置の第１の実施形態を示す概略構成図である。図１においてステンレス製の反応容器１１は、気密構造を有し、内部は所定の真空状態に保たれる。反応容器１１は排気機構１２を備え、これにより内部が真空状態にされる。反応容器１１の内部では、目的とする表面に所定の成膜が行われる基体１３が基体ホルダ１４の上に保持されている。基体ホルダ１４には、必要に応じて基体１３の温度を調節するための温度調節機構が設けられる。この温度調節機構は、基体１３の温度を検出する熱電対１５と加熱を行うヒータ１６と温度制御回路（図示せず）から構成される。また反応容器１１には、反応容器１１の内部圧力を測定するための、測定範囲が０．１〜１３３Ｐａの高精度ダイヤフラム真空計１７（例えばMKS 社製バラトロンTYPE128A）と、測定範囲が１０-2〜１０-6Ｐａの電離真空計１８（例えばアネルバ社製BAゲージUGD-1S）が取り付けられている。また１９は、添加ガスであるアンモニアを流量制御して反応容器１１に導入するためのアンモニア流量制御器であり、２０は、ＴＤＡＡＴを気化して反応容器１１に導入するための原料導入機構である。
【００３３】
原料導入機構２０について詳述する。２０ａは液体のＴＤＡＡＴを収容する容器であり、ステンレスで形成され、内壁は電解研磨処理を施している。容器２０ａの内部には、この例では具体的に液状のＴＤＥＡＴ２０ｂが充填されている。２０ｃは液状のＴＤＥＡＴの流量を測定する液体流量計、２０ｄはＴＤＥＡＴを気化させるための気化器である。気化器２０ｄの内部は所定の温度に調整されている。２０ｅはＴＤＥＡＴの気化効率を上げるため気化器２０ｄに導入されるキャリアガスの流量制御器である。
【００３４】
反応容器１１の外壁には、反応容器の外壁を所定温度に調節できる温度調節機構が設けられる。温度調節機構は、反応容器１１の温度を検出する熱電対２１と、加熱を行うヒータ２２と、温度制御回路（図示せず）から構成される。
【００３５】
一方、３１はステンレス製の処理容器である。この処理容器３１も、反応容器１１と同様に、気密構造を有し、内部は所定の真空状態に保たれる。処理容器３１は、排気機構３２を備え、内部には基体３３が配置された基体ホルダ３４を備える。基体ホルダ３４には、熱電対３５とヒータ３６と温度制御回路（図示せず）からなる温度調節機構が設けられる。さらに処理容器３１は、前述した高精度ダイヤフラム真空計１７と電離真空計１８と同様な、高精度ダイヤフラム真空計３７と電離真空計３８を備えている。３９は処理ガスであるアンモニア、水素、窒素を流量制御して処理容器３１に導入するための処理ガス流量制御器であり、４０は、高密度プラズマを安定させる目的で導入する安定化ガスであるアルゴンを流量制御して処理容器３１に導入するための安定化ガス流量制御器である。
【００３６】
処理ガス流量制御器３９で供給される処理ガスについては、アンモニア、水素、窒素、またはこれらのガスを選択的に混合したものが供給される。
【００３７】
処理容器３１には、その内部空間に高密度プラズマを発生させるための高密度プラズマ発生機構が設けられる。高密度プラズマ発生機構は、高密度プラズマ発生電極４１と電力供給源４２から構成される。高密度プラズマ発生電極４１は例えば金属製の円形板であり、基体３３に対向して配置されている。電力供給源４２はインピーダンス整合回路４３と高周波電源４４から構成される。高密度プラズマ発生電極４１の処理容器３１での導入部はインピーダンス整合回路４２を介して高周波電源４３に接続されている。
【００３８】
反応容器１１と処理容器３１の間には搬送容器５１が設けられる。搬送容器５１の内部には搬送機構５２が設けられる。搬送機構５２は、線図で概念的に示され、よく知られた従来機構が使用される。搬送機構５２によって、基体１３は、反応容器１１内の基体ホルダ１４から処理容器３１内の基体ホルダ３４へ搬送される。なお、搬送容器５２には、反応容器１１と処理容器３１を隔絶された空間とするため、ゲートバルブ５３とゲートバルブ５４が設けられる。また搬送容器５１には１０-5Ｐａまで排気可能な排気機構（図示せず）が設けられており、真空下で基体を搬送できるようになっている。
【００３９】
次に、上記構成を有する薄膜作製装置の動作を説明しながら、本発明の窒化チタンを主成分とする薄膜の作製方法について説明する。この薄膜作製装置の動作、すなわち窒化チタン薄膜の作製方法は、窒化チタンを主成分とする素薄膜を堆積する第１の工程と、当該素薄膜を高密度プラズマ処理によって改質する第２の工程とから構成される。
【００４０】
最初に第１の工程を説明する。まず、基体が搬送容器５１内に配置される。搬送容器５１内を排気した後、搬送機構５２により基体はゲートバルブ５３を通って反応容器１１内に導入され、基体ホルダ１４の上に保持される。基体１３は、基体ホルダ１４の上に保持された状態にある基体を示している。反応容器１１の内部は、排気機構１２によって例えば１０-5Ｐａ程度まで予め排気される。この際の圧力は電離真空計１８によって測定される。また、基体ホルダ１４はヒータ１６によって予め３００℃程度の温度に加熱され、基体１３もこの程度の温度に加熱された状態となる。
【００４１】
次に、予め０．５〜１Ｋｇ／ｃｍ2 の圧力のヘリウムで加圧されたＴＤＥＡＴ２０ｂを液体流量計２０ｃで流量制御した後、予め１００℃程度で加熱された気化器２０ｄによって気化後、反応容器１１内へ供給する。同時に、気化器２０ｄ内にはキャリアガスである例えば窒素がキャリアガス流量制御器２０ｅによって流量制御された後に導入され、ＴＤＥＡＴの気化効率を向上させている。さらに、同時に、添加ガスであるアンモニアをアンモニア流量制御器１９で流量制御した後、反応容器１１内に供給する。
【００４２】
反応容器１１内に供給されたＴＤＥＡＴガスとアンモニアは、基体ホルダ１４に設けた温度調節機構の熱によって加熱され、０．１〜１５Ｐａの反応容器１１内の圧力下で所定の化学反応が生じる。なお、化学反応を生じさせるときの圧力は高精度ダイヤフラム真空計１７で測定される。この結果、基体１３の表面には窒化チタンを主成分とする素薄膜が形成される。素薄膜の厚さが所定の値に達すると、ＴＤＥＡＴガス、キャリアガス、添加ガスの供給を止めた後に排気機構１２によって反応容器１１内を再び排気する。ここまでが第１の工程である。次に第２の工程を説明する。
【００４３】
窒化チタンを主成分とする素薄膜が形成された基体１３は、搬送機構５２によりゲートバルブ５３、ゲートバルブ５４を通って処理容器３１内に導入され、基体ホルダ３４に保持される。図１で、基体３３は、基体ホルダ３４の上に保持される基体１３であるとする。
【００４４】
処理容器３１の内部は、排気機構３２によって例えば１０-5Ｐａ程度まで予め排気される。なお、この際の圧力は、電離真空計３８によって測定される。また基体ホルダ３４は、ヒータ３６によって予め４００℃程度の温度に加熱され、従って基体３３もこの程度の温度に加熱された状態となる。
【００４５】
次に、処理ガスである窒素、水素、アンモニアを処理ガス流量制御器３９で流量制御した後、処理容器３１内へ供給する。同時に、安定化ガスであるアルゴンを安定化ガス流量制御器４０で流量制御した後、処理容器３１内に供給する。その際の処理容器３１内の圧力は高精度ダイヤフラム真空計３７で測定する。
【００４６】
次に、高周波電源４４より例えば周波数約６０ＭＨｚ、定格出力３ｋＷの電力が出力され、さらにインピーダンス整合回路４３でインピーダンス調整された後、処理容器３１内の高密度プラズマ発生電極４１へ供給される。これにより処理容器３１内に電子密度が１０10個／ｃｍ3 以上の高密度プラズマが発生し、各処理ガスの活性種により基体３３に形成された窒化チタンを主成分とする素薄膜が改質される。
【００４７】
上記のような高密度プラズマ処理を所定時間行った後、高密度プラズマ発生電極４１への電力供給を止め、また処理ガス、安定化ガスの供給を止める。さらに排気機構３２によって処理容器３１を再び排気する。このようにして第２の工程が終了する。
【００４８】
上記の第２の工程により、良好な被覆性を維持し、ダストの発生を抑え、作製された膜の電気特性が良好であって、経時的にも劣化せず化学的にも安定な膜が得られる。その後、基体３３は搬送機構５２によりゲートバルブ５４を介し、搬送容器５１に配置される。そして、搬送容器５１内の雰囲気を必要に応じて大気圧に戻し、基体は搬送容器５１から取り出される。
【００４９】
第２の工程を行うことによって上述のような効果が生ずる理由は、現時点では次のように推定される。
【００５０】
まず、ＴＤＡＡＴの熱ＣＶＤによる成膜では、蒸着やスパッタ等のような物理的手法により作製された薄膜と比較して、化学的に不安定であり、未結合の反応基やラジカル等を多く含んでいると考えられる。このような膜中に存在する反応基やラジカル等は、大気中の酸素を取り込んで酸化し、前述のように膜の比抵抗を増大させる原因となる。また、窒化チタンを主成分とする素薄膜の上に異種の薄膜が堆積された場合、反応基やラジカル等はその異種の薄膜の材料を取り込んで反応して何らかの化合物を生じ、この結果、膜質が変化して電気特性を劣化させる原因になると考えられる。
【００５１】
この状態で、第２の工程において上述のように各処理ガスの高密度プラズマを発生させた場合、水素またはアンモニアの活性種により膜中の不純物として存在する炭素を取り除き、さらに、窒素またはアンモニアの活性種により未結合の反応基やラジカル等を反応させ、素薄膜を化学量論組成に近づけた結果、大気中の酸素を取り込んで酸化したり、上層の材料を取り込んで膜質を劣化させたりするようなことが抑えられる。その結果、素薄膜自身の抵抗率を下げることができたと考えられる。
【００５２】
上記の実施形態では、高周波電源４４の周波数は約６０ＭＨｚを用いたが、約２７ＭＨｚ以上の周波数を用いた場合、電子密度が１０10個／ｃｍ3 以上の高密度プラズマを作製することができ、約６０ＭＨｚを用いた場合と同様に膜を改質することができた。また、高周波電源４４の周波数が約１５００ＭＨｚを越えると、同軸ケーブルでの電送が難しくなる。このため、本実施形態における高周波電源４４の周波数は約２７〜１５００ＭＨｚが有効である。特に、容易に電送でき、大電力整合回路が作製でき、高密度プラズマが得られたことから、約６０ＭＨｚの周波数の高周波電源４４は特に有用であった。
【００５３】
図２は本発明の薄膜作製装置の第２の実施形態を示す概略構成図である。図２において、図１を参照して説明された前述の第１実施形態の要素と実質的に同一の要素には同一の符号を付している。第２実施形態では、１つの容器で、前述の第１の工程と第２の工程が順次に行われる。ただし同一の容器で第１と第２の工程を行えるようにするため、途中でクリーニング工程を行うようにしている。
【００５４】
図２において、真空状態が可能な気密構造を有したステンレス製の反応容器６１の内部には基体ホルダ１４が設けられ、基体ホルダ１４の上には基体１３が保持される。基体ホルダ１４には熱電対１５とヒータ１６等からなる温度制御機構が設けられる。反応容器６１には排気機構１２が設けられ、排気機構１２は、反応容器の内部を所定の真空状態にする。また反応容器６１には、内部の圧力を測定するための前述した高精度ダイヤフラム真空計１７と、電離真空計１８が設けられる。
【００５５】
さらに、アンモニアを反応容器６１に導入するアンモニア流量制御器１９、気化したＴＤＡＡＴを反応容器６１に導入する原料導入機構２０が設けられる。原料導入機構２０は、液体のＴＤＥＡＴ２０ｂを充填する容器２０ａ、液体流量計２０ｃ、気化器２０ｄ、キャリアガスの流量制御器２０ｅからなる。
【００５６】
また反応容器６１の外壁には、反応容器の外壁を所定温度に調節できる温度調節機構が設けられる。温度調節機構は、反応容器６１の温度を検出する熱電対２１と、熱を与えるヒータ２２と、温度制御回路（図示せず）から構成される。
【００５７】
本実施形態による反応容器６１では、上記の構成に加え、反応容器６１の内部に高密度プラズマを発生するための高密度プラズマ発生機構が設けられる。高密度プラズマ発生機構は、高密度プラズマ発生電極４１と電力供給源４２から構成され、電力供給源４２はインピーダンス整合回路４３と高周波電源４４から構成される。さらに、反応容器６１内をプラズマクリーニングを行うためのクリーニング用電力供給源６２が設けられる。クリーニング用電力供給源６２はインピーダンス整合回路６３と高周波電源６４で構成されており、高周波電源６４はインピーダンス整合回路６３を介して基体ホルダ１４に接続されている。
【００５８】
また反応容器６１には、処理ガスであるアンモニア、水素、窒素を流量制御して処理容器６１内に導入する処理ガス流量制御器３９と、高密度プラズマを安定させる目的で導入する安定化ガスであるアルゴンを流量制御して処理容器６１内に導入する安定化ガス流量制御器４０が設けられる。
【００５９】
６５は、例えばＣＦ4 、Ｃ2 Ｆ6 、ＣＣｌ4 等のクリーニングガスを流量制御して反応容器６１内に供給するクリーニングガス流量制御器である。
【００６０】
次に、上記構成を有する薄膜作製装置の動作を説明しながら、窒化チタン薄膜の作製方法を説明する。
【００６１】
まず、成膜されるべき基体は、図示しない補助真空容器内に配置される。補助真空容器内を排気した後、図示しないゲートバルブを通って当該基体は反応容器６１内に導入され、基体ホルダ１４の上に保持される。図２では、基体ホルダ１４の上に保持された基体１３が示される。反応容器６１の内部は、排気機構１２によって例えば１０-5Ｐａ程度まで予め排気される。また基体ホルダ１４は温度調節機構のヒータ１６によって予め３００℃程度の温度に加熱され、基体１３もこの程度の温度に加熱された状態となる。
【００６２】
次に、原料導入機構２０によりＴＤＥＡＴ２０ｂを気体にして反応容器６１内へ供給すると同時に、アンモニアをアンモニア流量制御器１９で流量制御した後に反応容器６１内に供給する。反応容器６１内に供給されたＴＤＥＡＴガスとアンモニアは、基体ホルダ１４に設けた温度調節機構によって加熱され、０．１〜１５Ｐａの反応容器６１内の圧力下で所定の化学反応が生じる。この結果、基体１３の表面に窒化チタンを主成分とする素薄膜が形成される。素薄膜の厚さが所定の値に達すると、ＴＤＥＡＴガス、キャリアガス、添加ガスの供給を止めた後、排気機構１２によって反応容器６１内を再び排気する。以上が前述した第１の工程である。
【００６３】
次に、クリーニング工程が行われる。このクリーニング工程では、窒化チタンを主成分とする素薄膜が形成された基体１３は、図示しないゲートバルブを通って一度補助真空容器内に戻される。その後、反応容器６１内に所定のクリーニングガス、例えばＣＦ4 をクリーニングガス流量制御器６５で流量制御して供給する。さらにその後、高周波電源６４より例えば周波数１３．５６ＭＨｚ、定格出力１ｋＷの電力が出力され、さらにインピーダンス整合回路６３でインピーダンス調整された後、反応容器６１内の基体ホルダ１４に供給される。これにより反応容器６１内にプラズマを発生させ、反応容器６１内のクリーニングを行う。
【００６４】
本発明で採用しているＴＤＡＡＴは無機系の原料ガスＴｉＣｌ4 と比較して飽和蒸気圧が非常に低いという欠点がある。すなわち、第１の工程で窒化チタンを主成分とする素薄膜を形成した後には反応容器６１にＴＤＡＡＴに起因した残留物が残りやすく、反応容器６１でそのままの状態で第２の工程の高密度プラズマ処理を行うと、反応容器６１内がパーティクル汚染されるおそれがある。そこで第２の工程を行う前に反応容器６１で前述のクリーニングが行われる。
【００６５】
反応容器６１内でクリーニング工程を所定時間行った後、高周波電源６４の電力供給を止め、さらにクリーニングガスを止め、排気機構１２によって排気を行う。
【００６６】
以上のクリーニング工程を終了した後、図示しない補助真空容器内の窒化チタンを主成分とする素薄膜が形成された基体１３は、図示しないゲートバルブを通って再び反応容器６１内の基体ホルダ１４に保持される。
【００６７】
次に前述の第２の工程が行われる。まず、処理ガスである窒素、水素、アンモニアを処理ガス流量制御器３９で流量制御した後、反応容器６１内へ供給される。同時に安定化ガスであるアルゴンが安定化ガス流量制御器４０で流量制御した後、反応容器６１内に供給される。次に、高周波電源４４より前述の所定の電力が出力され、インピーダンス整合回路４３でインピーダンス調整された後、反応容器６１内の高密度プラズマ発生電極４１へ供給される。これにより反応容器６１内に前述した所定条件を満たす高密度プラズマが発生し、各処理ガスの活性種により基体１３に形成された窒化チタンを主成分とする素薄膜が改質される。高密度プラズマ処理を所定時間行った後、高密度プラズマ発生電極４１への電力供給を止め、処理ガスと安定化ガスの供給を止める。さらに排気機構１２によって反応容器６１内を再び排気する。こうして第２の工程が終了する。
【００６８】
その後基体１３はゲートバルブを介して補助真空容器へ搬送される。そして、補助真空容器内の雰囲気を必要に応じて大気圧に戻し、基体１３は補助真空容器から取り出される。
【００６９】
第２の実施形態による薄膜作製方法は、反応容器６１において、窒化チタンを主成分とする素薄膜を作製する第１の工程と、素薄膜を改質する第２の工程とを行うように構成され、第１の工程と第２の工程の間には、前述の理由によりクリーニング工程が行われる。第２の実施形態による薄膜作成装置によれば、装置の占有面積が半分以下の装置であっても同等の窒化チタンを主成分とする薄膜を得ることができる。
【００７０】
前述の各実施形態では、高密度プラズマ発生機構の高周波電源４４の周波数は約６０ＭＨｚのものを用いたが、約２７ＭＨｚ以上の周波数を用いた場合にも電子密度が１０10個／ｃｍ3 以上の高密度プラズマを作製することができ、上記実施形態を用いた場合と同様に膜を改質できる。また上記周波数が約１５００ＭＨｚを越えると、同軸ケーブルでの電送が難しくなる。このため、高周波電源４４の周波数は約２７〜１５００ＭＨｚが有効である。容易に電送可能で大電力整合回路が作製でき、高密度プラズマが得られたことから、約６０ＭＨｚの周波数が特に有用であった。
【００７１】
また高密度プラズマ発生機構として、内蔵アンテナ型高密度プラズマ源やヘリコン波励起プラズマ源を使用しても有効である。内蔵アンテナ型高密度プラズマ源とは、例えば、本発明の出願人が先に出願した特願平７−２８６３４２号、特願平７−２８８１１７号、特願平７−２８８１１８号等に記載されたプラズマ源である。またヘリコン波励起プラズマ源としては、例えばＰＭＴ社製のＭＯＲＩ１００プラズマ源を用いることができる。これらのプラズマ源を用いた場合には、高周波電源として約１００ｋＨｚ以上の周波数のものを用いたとき、電子密度が１０10個／ｃｍ3 以上の高密度プラズマを作製できた。この場合、約１３．５６ＭＨｚを用いた場合と同様に膜の改質に有効であった。整合回路の作製の観点から周波数として、約１〜１００ＭＨｚの高周波電源が有用である。特に、整合回路の作製については、周波数が高くなるため、コイル線が太く、ピッチの大きいコイルで大きなインダクタンスが得られ、そのため、コイル線の内部に水冷構造を設けることが可能であり、この種の周波数では水冷したコイルを使用することが可能となる。
【００７２】
その他に、ＥＣＲプラズマ源を使用した高密度プラズマ発生機構を用いた場合においても、ＴｉＮを主成分とする素薄膜の改質は効果的であった。
【００７３】
図３は、本発明の実施形態の方法によって窒化チタンを主成分とする薄膜を作製したときの実験結果を示す。図３で、横軸は窒化チタンを主成分とする薄膜作製後の大気露出時間を示し、縦軸は比抵抗を示している。図３で、グラフＡは、高密度プラズマ処理を行わない基体上の窒化チタンを主成分とする素薄膜の比抵抗の変化を示し、グラフＢは電子密度１０10個／ｃｍ3 に満たないプラズマ処理を行った窒化チタンを主成分とする薄膜の比抵抗の変化を示し、グラフＣは電子密度１０10個／ｃｍ3 に満たす前述の高密度プラズマ処理を行った窒化チタンを主成分とする薄膜の比抵抗の変化を示している。
【００７４】
図３から明らかなように、プラズマ処理を行わなかった窒化チタンを主成分とする素薄膜は、成膜後大気に晒すことによって徐々に比抵抗が増加し、１００時間程度経過した際には当初の３倍程度の比抵抗（１４０００μΩcm程度）にまで達している。これに対し、電子密度１０10個／ｃｍ3 に満たないプラズマ処理を行った窒化チタンを主成分とする薄膜は成膜当初の比抵抗も８００μΩcm程度と低く、その経時変化は１００時間程度経過した後も３０００μΩcmと処理を行わなかったときと比較して変化が少なかった。しかしながら、高密度プラズマ処理を行った際にはその比抵抗は５００μΩcmとさらに低下し、その経時変化も１００時間程度経過した後も殆ど変化が見られなかった。つまり電子密度１０10個／ｃｍ3 に満たないプラズマ処理の場合では、その膜厚深さ方向の改質が完全ではなく、高密度プラズマと比較してその比抵抗値および経時変化を完全に抑えられなかったことが起因していると考えられる。
【００７５】
上記のごとく、ＴＤＥＡＴの熱ＣＶＤにより作製された窒化チタンを主成分とする素薄膜に対して高密度プラズマ処理を行うことにより、成膜直後の比抵抗が小さくできるばかりでなく、作製した薄膜を大気に晒した場合でもその比抵抗は殆ど変化しないことが確認された。
【００７６】
前記の実施形態として、ＴＤＡＡＴとしてＴＤＥＡＴの例を説明したが、ＴＤＥＡＴの代わりにＴＤＭＡＴを用いることができるのは勿論である。
【００７７】
【発明の効果】
以上の説明で明らかなように本発明によれば、テトラキスジアルキルアミノチタンと、添加ガスを原料として、気体の状態で該原料を熱的に化学反応させ、基体の表面上に窒化チタンを主成分とする素薄膜を堆積した後、表面改質のためのプラズマ処理を行った結果、例えば２５６ＭビットＤＲＡＭのバリア層として要求されている、穴径０．２５μｍ、アスペクト比４．０のコンタクトホールを被覆率９０％以上で産業上有用である０．０２μｍ／min で成膜することができ、さらに、その比抵抗も例えば５００μΩcmまで小さくでき、その薄膜を大気に晒した場合でもその比抵抗は殆ど変化しない。このように本発明によれば、大気中の酸素を取り込んで酸化したり、上層の材料を取り込んで膜質を劣化させたりするようなことが抑えられる。
【図面の簡単な説明】
【図１】本発明に係る薄膜作製装置の第１の実施形態を示す概略構成図である。
【図２】本発明に係る薄膜作製装置の第２の実施形態を示し、反応容器にプラズマ発生機構を備えた構成を示す概略構成図である。
【図３】本発明に係る薄膜作製方法とその他の方法の各々によって窒化チタン薄膜を作製したときの比抵抗の経時変化を示すグラフである。
【符号の説明】
１１ 反応容器
１２ 排気機構
１３ 基体
１４ 基体ホルダ
２０ 原料導入機構
３１ 処理機構
３２ 廃棄機構
３３ 基体
３４ 基体ホルダ
３９ 処理ガス流量制御器
４０ 安定化ガス流量制御器
６２ クリーニング用電力源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for producing a thin film mainly composed of titanium nitride used as a diffusion prevention film, an adhesion layer film, an antireflection film, etc. constituting a semiconductor device, a superconducting device, various electronic components, various sensors, etc. About.
[0002]
[Prior art]
Preparation of semiconductor devices, superconducting devices, various electronic components, diffusion prevention films for various sensors, adhesion layer films, antireflection films, etc. on the surface of the substrate, vapor deposition, sputtering, chemical vapor deposition (CVD), plasma Film formation has been attempted by various methods such as an assisted CVD method.
[0003]
In recent years, as device integration has progressed, film formation with high coverage in holes and grooves having a high aspect ratio has been demanded. For example, as a technique for manufacturing a contact portion of a semiconductor integrated circuit, in order to prevent mutual diffusion between wiring tungsten (W) and base silicon (Si) and obtain stable electrical characteristics, or for logic integrated circuit wiring Cu Is a base or insulating layer (SiO 2 ) There is a need to produce a diffusion prevention film mainly composed of titanium nitride that prevents diffusion into the inside. Furthermore, an Al-Al adhesive layer is required as a through hole manufacturing technique for semiconductor integrated circuits. As the adhesion layer film, a thin film mainly composed of titanium nitride (hereinafter referred to as “titanium nitride thin film”) is also used, and it is required to form a film with good coverage at the bottom of a high aspect ratio hole. ing.
[0004]
On the other hand, one of the techniques that are attracting attention as a method for producing the titanium nitride thin film with relatively good coverage is a CVD technique using an organometallic compound or organometallic complex as a raw material. For example, M.Eizenberg et al., Appl.Phys.Lett.65 (19), 7 November 1994.P.2416-2418 describes the method. M. Eizenberg et al. Produced a titanium nitride thin film using only tetrakisdimethylaminotitanium (TDMAT) as a raw material at a deposition pressure of 0.45 Torr (60 Pa) and a substrate temperature of 380 to 470 ° C. The titanium nitride thin films produced by them are reported to contain about 23% oxygen by Rutherford backscattering analysis and about 24% oxygen by Auger electron spectroscopy.
[0005]
The above-mentioned oxygen content in the titanium nitride thin film is caused by being gradually oxidized in the atmosphere when the thin film is deposited. In general, a titanium nitride thin film produced by a CVD method using tetrakisdialkylaminotitanium (TDAAT) as a source gas is oxidized by the atmosphere and high concentration of oxygen is mixed. When oxygen contamination occurs, the resistance value of the film increases from the viewpoint of electrical characteristics. This is a serious drawback when the titanium nitride thin film is used for manufacturing various highly reliable electronic devices. In particular, a titanium nitride thin film cannot be used as a low resistance thin film because it is oxidized to increase the resistivity.
[0006]
Therefore, in order to solve the above problem, they do not expose the produced titanium nitride thin film to the atmosphere, but continuously deposit a tungsten thin film on the titanium nitride thin film to cut off the contact between the titanium nitride thin film and the atmosphere. Prevents oxidation. By performing this process, they were able to keep the oxygen content to 1%.
[0007]
However, a titanium nitride thin film produced by a thermal CVD method using TDAAT as a raw material gas is a chemically unstable film as compared with a film produced by a physical method such as vapor deposition. The method of blocking the atmosphere and preventing oxidation by depositing another film on such an unstable film fundamentally eliminates the characteristic of the titanium nitride thin film that is chemically unstable. Therefore, characteristic deterioration caused by long-term change such as change in chemical structure over time is unavoidable. From this fact, the production of titanium nitride thin films by thermal CVD using TDAAT has been evaluated as being excellent in terms of coverage and the like, but the reliability of electronic devices is also considered in terms of the electrical properties of the films produced. There has been a problem of reducing the sexiness.
[0008]
According to Conference Proceedings ULSI MRS 1994 P.223-P.237 by RL Jackson et al., RL Jackson et al. Formed a titanium nitride thin film using tetrakisdiethylaminotitanium (TDEAT) and ammonia as raw materials at a deposition pressure of 10 Torr (1333 Pa) and a substrate temperature of 350 ° C. It is made with. Even if the titanium nitride thin film produced by them is left in the atmosphere for one day or more after film formation, the resistance value can be suppressed to about 1%. However, only a coverage of less than 10% is obtained for a contact hole having a hole diameter of φ1.36 μm and an aspect ratio of 3.4. Further, dust is generated by a spatial reaction due to a high film forming pressure.
[0009]
In addition, according to US Pat. No. 5,254,499 of Gurtej S. Sandhu et al., As a result of producing a thin film mainly composed of TiN in the range of 5 to 100 Torr, the density is lower than that produced when it is produced at less than 5 Torr. A high film can be obtained. However, as described above, dust is generated by a spatial reaction due to a high film forming pressure.
[0010]
Further, there is a method described in Chin-Kun Wang et al. 1995 DRY PROCESS SYMPOSIUM p129-133 as a method for stabilizing the above chemically unstable film by post-processing with plasma. According to them, after forming a TiN film using TDMAT, N 2 Plasma post-treatment is applied. In this case, the plasma density is 10 Ten Piece / cm Three Since the amount is smaller, the post-processing time becomes longer, the throughput is delayed, and only the modification of only the film thickness of about several nanometers can be realized.
[0011]
[Problems to be solved by the invention]
As described above, the titanium nitride thin film fabrication technology using the thermal CVD method using TDAAT as a raw material is relatively excellent in terms of the coverage of holes and grooves with a high aspect ratio. There was a problem in terms. If film formation is performed with priority given to the electrical characteristics of the film, problems such as coverage and dust generation occur. Furthermore, the normal plasma density is 10 Ten Piece / cm Three Even when a plasma post-treatment less than 1 is performed, there is a problem that it can be expected only with a film having a very thin film thickness for which the throughput is delayed or modified.
[0012]
An object of the present invention is to solve the above-mentioned problem, and a thin film mainly composed of titanium nitride maintains a good covering property, suppresses the generation of dust, has good electrical characteristics of the film, and has changed over time. Another object of the present invention is to provide a thin film manufacturing method and a thin film manufacturing apparatus that are chemically stable without deterioration and can be manufactured with a short throughput.
[0013]
[Means and Actions for Solving the Problems]
The thin film manufacturing method according to the present invention is configured as follows in order to achieve the above object.
[0014]
In the first thin film production method (corresponding to claim 1), a raw material gas composed of vaporized tetrakisdialkylaminotitanium is heated in a gas state to cause a chemical reaction, and this chemical reaction has titanium nitride as a main component on the substrate. A thin film production method for producing a thin film, a first step of producing an elementary thin film mainly composed of titanium nitride on a substrate, ammonia, hydrogen , Ma Or these Mixed Combined processing gas Or a process gas that is a mixture of ammonia, hydrogen, and nitrogen Electron density is 10 in the atmosphere of 10 Piece / cm 3 It is characterized by comprising the second step of generating the above high-density plasma and modifying the elemental thin film with the activated processing gas.
[0015]
In the second thin film production method (corresponding to claim 2), the first step and the second step are performed in different containers in the first thin film production method, and in these containers, the substrate is carried by the transport mechanism.・ It is characterized by being carried out.
[0016]
The third thin film production method (corresponding to claim 3) is the first thin film production method, wherein the first step and the second step are performed in the same container, and the first step and the second step are performed. In , With the substrate removed from the container A cleaning process is performed.
[0017]
In the fourth thin film production method (corresponding to claim 4), in each of the thin film production methods described above, preferably, when generating high-density plasma in the second step, power having a frequency included in the range of 27 to 1500 MHz. It is characterized by using a high-frequency power supply for supplying power.
[0018]
According to a fifth thin film production method (corresponding to claim 5), in each of the thin film production methods described above, preferably, when the high density plasma is generated in the second step, a stabilizing gas that stabilizes the high density plasma is processed. It is characterized by being introduced together with gas.
[0019]
In the sixth thin film production method (corresponding to claim 6), in each of the thin film production methods described above, preferably, when the high density plasma is generated in the second step, the built-in antenna type high density plasma source, helicon wave excitation Either a plasma source or an ECR plasma source is used.
[0020]
A seventh thin film production method (corresponding to claim 7) is that, in the first thin film production method, tetrakisdialkylaminotitanium (TDAT) is tetrakisdimethylaminotitanium (TDMAT) or tetrakisdiethylaminotitanium (TDEAT). Features.
[0021]
The eighth thin film production method (corresponding to claim 8) is the third thin film production method, wherein in the cleaning step, the substrate is once taken out from the container in the same vacuum atmosphere without being exposed to the atmosphere, and the cleaning process in the container is performed. It is characterized by being.
[0022]
The thin film manufacturing apparatus according to the present invention is configured as follows in order to achieve the above object.
[0023]
A first thin film production apparatus (corresponding to claim 9) includes a reaction vessel having a gas-tight structure and a substrate holder for holding a substrate therein, a raw material introduction mechanism for introducing tetrakisdialkylaminotitanium into the reaction vessel, Equipped with an exhaust mechanism for exhausting the inside of the reaction chamber to a vacuum, a first process mechanism for producing an elemental thin film mainly composed of titanium nitride on a substrate, and a substrate holder having an airtight structure and holding the substrate inside Treatment vessel, a treatment gas introduction mechanism for introducing treatment gas into the treatment vessel, an exhaust mechanism for evacuating the treatment vessel to a vacuum, and an electron density of 10 in the treatment vessel. Ten Piece / cm Three A high-density plasma generation mechanism that generates the above-described high-density plasma is provided, and the reaction chamber and the processing container can be communicated in the same vacuum state with the second process mechanism that modifies the substrate thin film with the activated processing gas. And a transport mechanism for transporting the substrate from the reaction container to the processing container without exposing the substrate to the atmosphere.
[0024]
The second thin film manufacturing apparatus (corresponding to claim 10) is preferably the first thin film manufacturing apparatus, wherein the high-density plasma generating mechanism includes a high-frequency power source that supplies power having a frequency included in a range of 27 to 1500 MHz. It is characterized by that.
[0025]
The third thin film production apparatus (corresponding to claim 11) is the first thin film production apparatus, preferably the second process mechanism introduces a stabilization gas introduction mechanism for introducing a stabilization gas that stabilizes the high-density plasma. It is characterized by providing.
[0026]
The fourth thin film production apparatus (corresponding to claim 12) is the first thin film production apparatus. Preferably, the high density plasma generation mechanism of the second process mechanism is a built-in antenna type high density plasma source, helicon wave excitation. Either a plasma source or an ECR plasma source is provided.
[0027]
A fifth thin film production apparatus (corresponding to claim 13) includes a container provided with a base holder that has an airtight structure and holds a base therein, a raw material introduction mechanism that introduces tetrakisdialkylaminotitanium into the container, A processing gas introduction mechanism for introducing a processing gas into the container, an exhaust mechanism for exhausting the inside of the container to a vacuum, and an electron density of 10 in the container. Ten Piece / cm Three It is equipped with a high-density plasma generation mechanism that generates the above-mentioned high-density plasma, a cleaning mechanism that generates plasma in the container and cleans the inside of the container, and a take-out mechanism that takes the substrate out of the container during cleaning. The raw material gas of tetrakisdialkylaminotitanium supplied from the mechanism produces a thin film consisting mainly of titanium nitride on the surface of the substrate on the substrate holder, and then the cleaning mechanism with the substrate removed from the container by the removal mechanism Then, the inside of the container is cleaned, and then the substrate thin film is modified with the processing gas supplied by the processing gas introduction mechanism while the substrate is again held on the substrate holder.
[0028]
The sixth thin film manufacturing apparatus (corresponding to claim 14) is the fifth thin film manufacturing apparatus, preferably, the high-density plasma generation mechanism includes a high-frequency power source that supplies power having a frequency included in a range of 27 to 1500 MHz. It is characterized by that.
[0029]
The seventh thin film production apparatus (corresponding to claim 15) is the fifth thin film production apparatus, preferably comprising a stabilizing gas introduction mechanism for introducing a stabilizing gas that stabilizes the high-density plasma. .
[0030]
The eighth thin film production apparatus (corresponding to claim 16) is the fifth thin film production apparatus, preferably, the high-density plasma generation mechanism is a built-in antenna type high-density plasma source, helicon wave excitation plasma source, ECR plasma source. Any one of these is provided.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0032]
FIG. 1 is a schematic configuration diagram showing a first embodiment of a thin film manufacturing apparatus of the present invention. In FIG. 1, a stainless steel reaction vessel 11 has an airtight structure, and the inside is kept in a predetermined vacuum state. The reaction vessel 11 is provided with an exhaust mechanism 12, and the inside is thereby evacuated. Inside the reaction vessel 11, a substrate 13 on which a predetermined film is formed on a target surface is held on a substrate holder 14. The substrate holder 14 is provided with a temperature adjustment mechanism for adjusting the temperature of the substrate 13 as necessary. The temperature adjusting mechanism includes a thermocouple 15 that detects the temperature of the base 13, a heater 16 that performs heating, and a temperature control circuit (not shown). The reaction vessel 11 includes a high-accuracy diaphragm vacuum gauge 17 (for example, Baratron TYPE128A manufactured by MKS) for measuring the internal pressure of the reaction vessel 11 and a measurement range of 10 -2 -10 -6 A Pa ionization gauge 18 (for example, BA gauge UGD-1S manufactured by Anelva) is attached. Reference numeral 19 is an ammonia flow controller for controlling the flow rate of ammonia as an additive gas and introducing it into the reaction vessel 11, and 20 is a raw material introduction mechanism for vaporizing TDAAT and introducing it into the reaction vessel 11. .
[0033]
The raw material introduction mechanism 20 will be described in detail. Reference numeral 20a denotes a container for storing liquid TDAAT, which is made of stainless steel and whose inner wall is subjected to electrolytic polishing. The container 20a is specifically filled with liquid TDEAT 20b in this example. 20c is a liquid flowmeter for measuring the flow rate of liquid TDEAT, and 20d is a vaporizer for vaporizing TDEAT. The inside of the vaporizer 20d is adjusted to a predetermined temperature. Reference numeral 20e denotes a flow rate controller for the carrier gas introduced into the vaporizer 20d to increase the vaporization efficiency of TDEAT.
[0034]
The outer wall of the reaction vessel 11 is provided with a temperature adjustment mechanism that can adjust the outer wall of the reaction vessel to a predetermined temperature. The temperature adjustment mechanism includes a thermocouple 21 that detects the temperature of the reaction vessel 11, a heater 22 that performs heating, and a temperature control circuit (not shown).
[0035]
On the other hand, 31 is a processing container made of stainless steel. Similar to the reaction vessel 11, the processing vessel 31 also has an airtight structure, and the inside is kept in a predetermined vacuum state. The processing container 31 includes an exhaust mechanism 32 and includes a substrate holder 34 in which a substrate 33 is disposed. The base holder 34 includes a thermocouple 3. 5 And heater 3 6 And a temperature control mechanism comprising a temperature control circuit (not shown). Further, the processing vessel 31 includes a high-precision diaphragm vacuum gauge 37 and an ionization vacuum gauge 38 similar to the high-precision diaphragm vacuum gauge 17 and the ionization vacuum gauge 18 described above. 39 is a process gas flow controller for controlling the flow of ammonia, hydrogen, and nitrogen, which are process gases, and introducing them into the process vessel 31, and 40 is a stabilizing gas introduced for the purpose of stabilizing the high-density plasma. This is a stabilized gas flow rate controller for introducing argon into the processing vessel 31 while controlling the flow rate of argon.
[0036]
As for the processing gas supplied by the processing gas flow controller 39, ammonia, hydrogen, nitrogen, or a gas obtained by selectively mixing these gases is supplied.
[0037]
The processing container 31 is provided with a high-density plasma generation mechanism for generating high-density plasma in the internal space. The high-density plasma generation mechanism includes a high-density plasma generation electrode 41 and a power supply source 42. The high-density plasma generating electrode 41 is a metal circular plate, for example, and is disposed to face the base 33. The power supply source 42 includes an impedance matching circuit 43 and a high frequency power supply 44. The introduction portion of the high-density plasma generating electrode 41 in the processing container 31 is connected to a high-frequency power source 43 through an impedance matching circuit 42.
[0038]
A transfer container 51 is provided between the reaction container 11 and the processing container 31. A transport mechanism 52 is provided inside the transport container 51. The transport mechanism 52 is conceptually shown in a diagram, and a well-known conventional mechanism is used. The substrate 13 is transferred from the substrate holder 14 in the reaction vessel 11 to the substrate holder 34 in the processing vessel 31 by the transfer mechanism 52. The transfer container 52 is provided with a gate valve 53 and a gate valve 54 so that the reaction container 11 and the processing container 31 are separated from each other. The transfer container 51 has 10 -Five An exhaust mechanism (not shown) capable of exhausting to Pa is provided so that the substrate can be conveyed under vacuum.
[0039]
Next, a method for producing a thin film mainly composed of titanium nitride according to the present invention will be described while explaining the operation of the thin film production apparatus having the above-described configuration. The operation of this thin film forming apparatus, that is, a method for manufacturing a titanium nitride thin film includes a first step of depositing an elementary thin film containing titanium nitride as a main component and a second step of modifying the elementary thin film by high-density plasma treatment. It consists of.
[0040]
First, the first step will be described. First, the substrate is placed in the transport container 51. After exhausting the inside of the transport container 51, the substrate is introduced into the reaction container 11 through the gate valve 53 by the transport mechanism 52 and held on the substrate holder 14. The base 13 is a base that is held on the base holder 14. The inside of the reaction vessel 11 is, for example, 10 by the exhaust mechanism 12. -Five Exhaust in advance to about Pa. The pressure at this time is measured by the ionization vacuum gauge 18. Further, the substrate holder 14 is preheated to a temperature of about 300 ° C. by the heater 16, and the substrate 13 is also heated to this temperature.
[0041]
Next, 0.5-1 kg / cm in advance 2 The flow rate of TDEAT 20b pressurized with helium at a pressure of 5 is controlled by the liquid flow meter 20c, and then vaporized by the vaporizer 20d heated in advance at about 100 ° C., and then supplied into the reaction vessel 11. At the same time, for example, nitrogen, which is a carrier gas, is introduced into the vaporizer 20d after the flow rate is controlled by the carrier gas flow rate controller 20e, thereby improving the vaporization efficiency of TDEAT. At the same time, ammonia, which is an additive gas, is flow-controlled by the ammonia flow controller 19 and then supplied into the reaction vessel 11.
[0042]
The TDEAT gas and ammonia supplied into the reaction vessel 11 are heated by the heat of the temperature adjusting mechanism provided in the substrate holder 14, and a predetermined chemical reaction occurs under a pressure in the reaction vessel 11 of 0.1 to 15 Pa. Note that the pressure at which the chemical reaction is caused is measured by a high-accuracy diaphragm vacuum gauge 17. As a result, an elemental thin film mainly composed of titanium nitride is formed on the surface of the base 13. When the thickness of the raw thin film reaches a predetermined value, the supply of the TDEAT gas, the carrier gas, and the additive gas is stopped, and the inside of the reaction vessel 11 is exhausted again by the exhaust mechanism 12. This is the first step. Next, the second step will be described.
[0043]
The substrate 13 on which the elemental thin film mainly composed of titanium nitride is formed is introduced into the processing container 31 through the gate valve 53 and the gate valve 54 by the transport mechanism 52 and is held by the substrate holder 34. In FIG. 1, the base 33 is assumed to be the base 13 held on the base holder 34.
[0044]
The inside of the processing container 31 is, for example, 10 by the exhaust mechanism 32. -Five Exhaust in advance to about Pa. The pressure at this time is measured by an ionization vacuum gauge 38. In addition, the base holder 34 is preheated to a temperature of about 400 ° C. by the heater 36, so that the base 33 is also heated to this temperature.
[0045]
Next, nitrogen, hydrogen, and ammonia, which are processing gases, are flow-controlled by the processing gas flow controller 39 and then supplied into the processing container 31. At the same time, argon, which is a stabilizing gas, is flow-controlled by the stabilizing gas flow controller 40 and then supplied into the processing vessel 31. The pressure in the processing vessel 31 at that time is measured by a high-accuracy diaphragm vacuum gauge 37.
[0046]
Next, power having a frequency of, for example, about 60 MHz and a rated output of 3 kW is output from the high-frequency power supply 44, and further impedance adjusted by the impedance matching circuit 43, and then supplied to the high-density plasma generating electrode 41 in the processing vessel 31. As a result, the electron density is 10 in the processing container 31. Ten Piece / cm Three The above high-density plasma is generated, and the elemental thin film mainly composed of titanium nitride formed on the substrate 33 is modified by the active species of each processing gas.
[0047]
After the high-density plasma treatment as described above is performed for a predetermined time, the power supply to the high-density plasma generation electrode 41 is stopped, and the supply of the processing gas and the stabilizing gas is stopped. Further, the processing container 31 is exhausted again by the exhaust mechanism 32. In this way, the second step is completed.
[0048]
By the above second step, it is possible to maintain a good covering property, suppress the generation of dust, the electrical characteristics of the produced film are good, and a chemically stable film that does not deteriorate over time. can get. Thereafter, the substrate 33 is placed in the transfer container 51 by the transfer mechanism 52 via the gate valve 54. Then, the atmosphere in the transport container 51 is returned to atmospheric pressure as necessary, and the substrate is taken out from the transport container 51.
[0049]
The reason why the above-described effect is produced by performing the second step is estimated as follows at present.
[0050]
First, TDAAT film formation by thermal CVD is chemically unstable and contains a lot of unbonded reactive groups and radicals as compared with thin films prepared by physical methods such as vapor deposition and sputtering. It is thought that Such reactive groups and radicals present in the film take in oxygen in the atmosphere and oxidize it, causing the specific resistance of the film to increase as described above. In addition, when a different kind of thin film is deposited on an elemental thin film containing titanium nitride as a main component, reactive groups, radicals, etc. take in the material of the different kind of thin film and react to form some compound, resulting in film quality. It is considered that this causes the electrical characteristics to deteriorate due to the change.
[0051]
In this state, when high-density plasma of each processing gas is generated in the second step as described above, carbon present as impurities in the film is removed by active species of hydrogen or ammonia, and further, nitrogen or ammonia As a result of reacting unbonded reactive groups or radicals with active species and bringing the elementary thin film close to the stoichiometric composition, oxygen in the atmosphere is taken in and oxidized, or upper layer material is taken in and the film quality is deteriorated. This can be suppressed. As a result, it is considered that the resistivity of the elemental thin film itself could be lowered.
[0052]
In the above embodiment, the frequency of the high frequency power supply 44 is about 60 MHz. However, when a frequency of about 27 MHz or more is used, the electron density is 10. Ten Piece / cm Three The above high-density plasma could be produced, and the film could be modified in the same manner as when about 60 MHz was used. Moreover, when the frequency of the high frequency power supply 44 exceeds about 1500 MHz, it is difficult to transmit power with a coaxial cable. For this reason, about 27-1500 MHz is effective as the frequency of the high frequency power supply 44 in this embodiment. In particular, the high-frequency power supply 44 having a frequency of about 60 MHz is particularly useful because it can be easily transmitted, a high-power matching circuit can be manufactured, and a high-density plasma can be obtained.
[0053]
FIG. 2 is a schematic configuration diagram showing a second embodiment of the thin film manufacturing apparatus of the present invention. In FIG. 2, elements that are substantially the same as those of the first embodiment described with reference to FIG. In the second embodiment, the first step and the second step described above are sequentially performed in one container. However, in order to perform the first and second steps in the same container, the cleaning step is performed halfway.
[0054]
In FIG. 2, a substrate holder 14 is provided inside a stainless steel reaction vessel 61 having an airtight structure capable of being in a vacuum state, and the substrate 13 is held on the substrate holder 14. The substrate holder 14 is provided with a temperature control mechanism including a thermocouple 15 and a heater 16. The reaction vessel 61 is provided with an exhaust mechanism 12, and the exhaust mechanism 12 places the inside of the reaction vessel in a predetermined vacuum state. The reaction vessel 61 is provided with the above-described high-accuracy diaphragm vacuum gauge 17 and ionization vacuum gauge 18 for measuring the internal pressure.
[0055]
In addition, ammonia in the reaction vessel 6 1 Ammonia flow controller to be introduced 19 , The vaporized TDAAT in a reaction vessel 6 1 is provided with a raw material introduction mechanism 20. The raw material introduction mechanism 20 includes a container 20a filled with liquid TDEAT 20b, a liquid flow meter 20c, a vaporizer 20d, and a carrier gas flow controller 20e.
[0056]
The outer wall of the reaction vessel 61 is provided with a temperature adjustment mechanism that can adjust the outer wall of the reaction vessel to a predetermined temperature. The temperature adjustment mechanism includes a thermocouple 21 that detects the temperature of the reaction vessel 61, a heater 22 that applies heat, and a temperature control circuit (not shown).
[0057]
In the reaction vessel 61 according to the present embodiment, in addition to the above configuration, a high-density plasma generation mechanism for generating high-density plasma is provided inside the reaction vessel 61. The high-density plasma generation mechanism includes a high-density plasma generation electrode 41 and a power supply source 42, and the power supply source 42 includes an impedance matching circuit 43 and a high-frequency power supply 44. Further, a cleaning power supply source 62 for performing plasma cleaning in the reaction vessel 61 is provided. The cleaning power supply source 62 includes an impedance matching circuit 63 and a high frequency power source 64, and the high frequency power source 64 is connected to the substrate holder 14 via the impedance matching circuit 63.
[0058]
The reaction vessel 61 includes a processing gas flow rate controller 39 for controlling the flow rates of ammonia, hydrogen, and nitrogen as processing gases and introducing them into the processing vessel 61, and a stabilizing gas introduced for the purpose of stabilizing high-density plasma. A stabilized gas flow rate controller 40 is provided for controlling the flow rate of certain argon into the processing vessel 61.
[0059]
65 is, for example, CF Four , C 2 F 6 , CCl Four This is a cleaning gas flow rate controller for controlling the flow rate of cleaning gas such as the like and supplying it into the reaction vessel 61.
[0060]
Next, a method for manufacturing a titanium nitride thin film will be described while explaining the operation of the thin film manufacturing apparatus having the above configuration.
[0061]
First, a substrate to be deposited is placed in an auxiliary vacuum vessel (not shown). After evacuating the auxiliary vacuum vessel, the substrate is introduced into the reaction vessel 61 through a gate valve (not shown) and held on the substrate holder 14. In FIG. 2, the substrate 13 held on the substrate holder 14 is shown. The inside of the reaction vessel 61 is, for example, 10 by the exhaust mechanism 12. -Five Exhaust in advance to about Pa. The substrate holder 14 is preheated to a temperature of about 300 ° C. by the heater 16 of the temperature adjusting mechanism, and the substrate 13 is also heated to this temperature.
[0062]
Next, TDEAT 20 b is converted into a gas by the raw material introduction mechanism 20 and supplied into the reaction vessel 61, and ammonia is supplied into the reaction vessel 61 after the flow rate of the ammonia is controlled by the ammonia flow rate controller 19. The TDEAT gas and ammonia supplied into the reaction vessel 61 are heated by a temperature adjusting mechanism provided in the substrate holder 14, and a predetermined chemical reaction occurs under a pressure in the reaction vessel 61 of 0.1 to 15 Pa. As a result, an elemental thin film mainly composed of titanium nitride is formed on the surface of the base 13. When the thickness of the raw thin film reaches a predetermined value, the supply of the TDEAT gas, the carrier gas, and the additive gas is stopped, and then the inside of the reaction vessel 61 is exhausted again by the exhaust mechanism 12. The above is the first step described above.
[0063]
Next, a cleaning process is performed. In this cleaning process, the substrate 13 on which the elemental thin film mainly composed of titanium nitride is formed is once returned to the auxiliary vacuum vessel through a gate valve (not shown). Thereafter, a predetermined cleaning gas such as CF Four Is supplied after the flow rate is controlled by the cleaning gas flow rate controller 65. Thereafter, power having a frequency of 13.56 MHz and a rated output of 1 kW, for example, is output from the high-frequency power source 64, further impedance-adjusted by the impedance matching circuit 63, and then supplied to the substrate holder 14 in the reaction vessel 61. As a result, plasma is generated in the reaction vessel 61 to clean the reaction vessel 61.
[0064]
The TDAAT employed in the present invention is an inorganic source gas TiCl. Four There is a disadvantage that the saturated vapor pressure is very low. That is, after forming the elemental thin film mainly composed of titanium nitride in the first step, the residue due to TDAAT tends to remain in the reaction vessel 61, and the high density of the second step is left as it is in the reaction vessel 61. When the plasma treatment is performed, the inside of the reaction vessel 61 may be contaminated with particles. Therefore, the above-described cleaning is performed in the reaction vessel 61 before performing the second step.
[0065]
After performing the cleaning process in the reaction vessel 61 for a predetermined time, the power supply of the high frequency power supply 64 is stopped, the cleaning gas is stopped, and the exhaust mechanism 12 exhausts the gas.
[0066]
After the above cleaning process is completed, the substrate 13 on which the elemental thin film mainly composed of titanium nitride in the auxiliary vacuum vessel (not shown) is formed again passes through the gate valve (not shown) to the substrate holder 14 in the reaction vessel 61 again. Retained.
[0067]
Next, the second step described above is performed. First, nitrogen, hydrogen, and ammonia as processing gases The After the flow rate is controlled by the processing gas flow rate controller 39, the gas is supplied into the reaction vessel 61. At the same time, argon, which is a stabilizing gas, is flow-controlled by the stabilizing gas flow controller 40 and then supplied into the reaction vessel 61. Next, the predetermined power described above is output from the high frequency power supply 44, the impedance is adjusted by the impedance matching circuit 43, and then supplied to the high density plasma generating electrode 41 in the reaction vessel 61. As a result, high-density plasma that satisfies the above-described predetermined conditions is generated in the reaction vessel 61, and the elemental thin film mainly composed of titanium nitride formed on the substrate 13 is modified by the active species of each processing gas. After performing the high density plasma treatment for a predetermined time, the power supply to the high density plasma generating electrode 41 is stopped, and the supply of the processing gas and the stabilizing gas is stopped. Further, the inside of the reaction vessel 61 is exhausted again by the exhaust mechanism 12. Thus, the second process is completed.
[0068]
Thereafter, the substrate 13 is transferred to the auxiliary vacuum vessel via the gate valve. Then, the atmosphere in the auxiliary vacuum vessel is returned to atmospheric pressure as necessary, and the substrate 13 is taken out of the auxiliary vacuum vessel.
[0069]
The thin film production method according to the second embodiment is configured to perform, in the reaction vessel 61, a first step of producing a raw thin film mainly composed of titanium nitride and a second step of modifying the raw thin film. In addition, a cleaning process is performed between the first process and the second process for the reasons described above. According to the thin film forming apparatus according to the second embodiment, a thin film mainly composed of equivalent titanium nitride can be obtained even if the apparatus occupies half or less of the area.
[0070]
In each of the embodiments described above, the frequency of the high-frequency power supply 44 of the high-density plasma generation mechanism is about 60 MHz. However, the electron density is 10 even when a frequency of about 27 MHz or more is used. Ten Piece / cm Three The above high-density plasma can be produced, and the film can be modified as in the case of using the above embodiment. On the other hand, if the frequency exceeds about 1500 MHz, it is difficult to transmit with a coaxial cable. For this reason, the frequency of the high frequency power supply 44 is effectively about 27 to 1500 MHz. A frequency of about 60 MHz was particularly useful because it could be easily transmitted and a high power matching circuit could be produced and a high density plasma was obtained.
[0071]
It is also effective to use a built-in antenna type high-density plasma source or a helicon wave excitation plasma source as a high-density plasma generation mechanism. The built-in antenna type high-density plasma source is described in, for example, Japanese Patent Application No. 7-286342, Japanese Patent Application No. 7-288117, Japanese Patent Application No. 7-288118, etc. filed earlier by the applicant of the present invention. It is a plasma source. As the helicon wave excitation plasma source, for example, an MORI100 plasma source manufactured by PMT can be used. When these plasma sources are used, when a high frequency power source having a frequency of about 100 kHz or more is used, the electron density is 10. Ten Piece / cm Three The above high-density plasma could be produced. In this case, it was effective for reforming the membrane as in the case of using about 13.56 MHz. From the viewpoint of manufacturing the matching circuit, a high frequency power source of about 1 to 100 MHz is useful as a frequency. In particular, for the production of the matching circuit, since the frequency increases, the coil wire is thick and the coil having a large pitch provides a large inductance. Therefore, it is possible to provide a water cooling structure inside the coil wire. It is possible to use a water-cooled coil at a frequency of.
[0072]
In addition, even when a high-density plasma generation mechanism using an ECR plasma source is used, the modification of the elemental thin film mainly composed of TiN is effective.
[0073]
FIG. 3 shows experimental results when a thin film mainly composed of titanium nitride is produced by the method of the embodiment of the present invention. In FIG. 3, the horizontal axis indicates the atmospheric exposure time after forming a thin film mainly composed of titanium nitride, and the vertical axis indicates the specific resistance. In FIG. 3, a graph A shows a change in specific resistance of an elemental thin film mainly composed of titanium nitride on a substrate not subjected to high-density plasma treatment, and a graph B shows an electron density of 10 Ten Piece / cm Three The graph shows the change in the specific resistance of a thin film mainly composed of titanium nitride that has been subjected to a plasma treatment that is less than 1, and graph C shows an electron density of 10 Ten Piece / cm Three 3 shows a change in specific resistance of a thin film mainly composed of titanium nitride subjected to the above-described high-density plasma treatment that satisfies the above.
[0074]
As is clear from FIG. 3, the resistivity of the elemental thin film mainly composed of titanium nitride that has not been subjected to plasma treatment gradually increases when exposed to the atmosphere after film formation. The specific resistance is about 3 times as high as 14,000 μΩcm. In contrast, an electron density of 10 Ten Piece / cm Three A thin film mainly composed of titanium nitride subjected to plasma treatment that is less than 1 has a low specific resistance of about 800 μΩcm at the beginning of film formation, and its change with time is 3000 μΩcm after about 100 hours, compared with when the treatment was not performed. There was little change. However, when the high-density plasma treatment was performed, the specific resistance further decreased to 500 μΩcm, and the change with time was hardly observed even after about 100 hours. That is, the electron density is 10 Ten Piece / cm Three In the case of plasma treatment that is less than 1, the modification in the depth direction of the film thickness is not complete, and the specific resistance value and the change with time are not completely suppressed as compared with high-density plasma. it is conceivable that.
[0075]
As described above, by performing high-density plasma treatment on the elemental thin film mainly composed of titanium nitride produced by thermal CVD of TDEAT, not only the specific resistance immediately after film formation can be reduced, but also the produced thin film It was confirmed that the resistivity hardly changed even when exposed to the atmosphere.
[0076]
In the above embodiment, an example of TDEAT has been described as TDAT, but it is needless to say that TDMAT can be used instead of TDEAT.
[0077]
【The invention's effect】
As is apparent from the above description, according to the present invention, tetrakisdialkylaminotitanium and an additive gas as a raw material are thermally chemically reacted in a gaseous state, and titanium nitride is a main component on the surface of the substrate. As a result of performing a plasma treatment for surface modification after depositing an elemental thin film, a contact hole having a hole diameter of 0.25 μm and an aspect ratio of 4.0, which is required as a barrier layer of a 256 Mbit DRAM, for example, is obtained. Films can be formed at 0.02 μm / min, which is industrially useful when the coverage is 90% or more, and the specific resistance can be reduced to, for example, 500 μΩcm. Even when the thin film is exposed to the atmosphere, the specific resistance is almost zero. It does not change. Thus according to the present invention If Incorporating oxygen in the atmosphere to oxidize it, or taking in the material of the upper layer and degrading the film quality can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a first embodiment of a thin film manufacturing apparatus according to the present invention.
FIG. 2 is a schematic configuration diagram showing a second embodiment of a thin film production apparatus according to the present invention and showing a configuration in which a plasma generation mechanism is provided in a reaction vessel.
FIG. 3 is a graph showing a change in specific resistance with time when a titanium nitride thin film is produced by each of the thin film production method according to the present invention and other methods.
[Explanation of symbols]
11 reaction vessel
12 Exhaust mechanism
13 Base
14 Substrate holder
20 Raw material introduction mechanism
31 Processing mechanism
32 Disposal mechanism
33 Base
34 Base holder
39 Process gas flow controller
40 Stabilized gas flow controller
62 Power source for cleaning

Claims (16)

気化したテトラキスジアルキルアミノチタンよりなる原料ガスを気体状態で加熱して化学反応させ、この化学反応によって基体上に窒化チタンを主成分とする薄膜を作製する薄膜作製方法において、
前記窒化チタンを主成分とする素薄膜を前記基体上に作製する第１の工程と、アンモニア、水素、またはこれらを混合してなる処理ガス、あるいはアンモニア、水素、窒素を混合してなる処理ガスの雰囲気下で電子密度が１０１０個／ｃｍ３以上の高密度プラズマを発 生させ、活性化した前記処理ガスによって前記素薄膜を改質する第２の工程とからなることを特徴とする薄膜作製方法。In a thin film production method for producing a thin film containing titanium nitride as a main component on a substrate by a chemical reaction by heating a vaporized tetrakisdialkylaminotitanium raw material gas in a gaseous state,
A first step of preparing a prime film on the basis of the titanium nitride on the substrate, ammonia, hydrogen, these combined mixed formed by the process gas was or alternatively ammonia, by mixing hydrogen, nitrogen comprising the electron density in the atmosphere of the processing gas is raised calling the 10 10 / cm 3 or more high-density plasma, characterized in that it consists of a second step of modifying the element thin film by the process gas activation A method for producing a thin film. 前記第１の工程と前記第２の工程は異なる容器で行われ、これらの容器で、前記基体は搬送機構によって搬入・搬出されることを特徴とする請求項１記載の薄膜作製方法。  2. The thin film manufacturing method according to claim 1, wherein the first step and the second step are performed in different containers, and the base is carried in and out by a transport mechanism in these containers. 前記第１の工程と前記第２の工程は同じ容器で行われ、第１の工程と第２の工程の間に、前記基体を前記容器から取り出した状態で前記容器内のクリーニング工程が行われることを特徴とする請求項１記載の薄膜作製方法。  The first process and the second process are performed in the same container, and the cleaning process in the container is performed between the first process and the second process in a state where the substrate is removed from the container. The thin film manufacturing method according to claim 1. 前記第２の工程で前記高密度プラズマを発生させる際、２７〜１５００ＭＨｚの範囲に含まれる周波数の電力を供給する高周波電源を使用することを特徴とする請求項１〜３のいずれか１項に記載の薄膜作製方法。  The high-frequency power source that supplies power having a frequency included in a range of 27 to 1500 MHz is used when generating the high-density plasma in the second step. The thin film preparation method described. 前記第２の工程で前記高密度プラズマを発生させる際、前記高密度プラズマを安定させる安定化ガスを前記処理ガスと共に導入することを特徴とする請求項１〜３のいずれか１項に記載の薄膜作製方法。  The stabilization gas that stabilizes the high-density plasma is introduced together with the processing gas when the high-density plasma is generated in the second step. Thin film manufacturing method. 前記第２の工程で前記高密度プラズマを発生させる際、内蔵アンテナ型高密度プラズマ源、ヘリコン波励起プラズマ源、ＥＣＲプラズマ源のうちいずれかを使用することを特徴とする請求項１〜３のいずれか１項に記載の薄膜作製方法。  4. When generating the high-density plasma in the second step, any one of a built-in antenna type high-density plasma source, a helicon wave excitation plasma source, and an ECR plasma source is used. The thin film manufacturing method of any one of Claims 1. 前記テトラキスジアルキルアミノチタンが、テトラキスジメチルアミノチタンまたはテトラキスジエチルアミノチタンであることを特徴とする請求項１記載の薄膜作製方法。  The method for producing a thin film according to claim 1, wherein the tetrakisdialkylaminotitanium is tetrakisdimethylaminotitanium or tetrakisdiethylaminotitanium. 前記クリーニング工程では、前記基体を大気に晒すことなく前記容器から同一真空雰囲気で一旦取り出し、前記容器内のクリーニング処理が行われることを特徴とする請求項３記載の薄膜作製方法。  4. The thin film manufacturing method according to claim 3, wherein, in the cleaning step, the substrate is once taken out from the container in the same vacuum atmosphere without being exposed to the atmosphere, and a cleaning process in the container is performed. 気密構造を有し内部に基体を保持する基体ホルダを備えた反応容器と、この反応容器内にテトラキスジアルキルアミノチタンを導入する原料導入機構と、前記反応容器内を真空に排気する排気機構を備え、窒化チタンを主成分とする素薄膜を基体上に作製する第１工程用機構と、
気密構造を有し内部に前記基体を保持する基体ホルダを備えた処理容器と、この処理容器に処理ガスを導入する処理ガス導入機構と、前記処理容器内を真空に排気する排気機構と、前記処理容器内に電子密度が１０１０個／ｃｍ３以上の高密度プラズマを発生させる高密度プラズマ発生機構を備え、活性化した前記処理ガスによって前記基体の前記素薄膜を改質する第２工程用機構と、
前記反応容器と前記処理容器を同じ真空状態で連通可能にし、前記基体を大気に晒すことなく前記反応容器から前記処理容器に搬送する搬送機構と、
を備えることを特徴とする薄膜作製装置。A reaction vessel having an airtight structure and a substrate holder for holding a substrate therein, a raw material introduction mechanism for introducing tetrakisdialkylaminotitanium into the reaction vessel, and an exhaust mechanism for evacuating the reaction vessel to a vacuum , A first process mechanism for producing an elemental thin film mainly composed of titanium nitride on a substrate;
A processing container having an airtight structure and a substrate holder for holding the substrate therein; a processing gas introduction mechanism for introducing a processing gas into the processing container; an exhaust mechanism for exhausting the inside of the processing container to a vacuum; For a second step of providing a high-density plasma generating mechanism for generating high-density plasma having an electron density of 10 10 atoms / cm 3 or more in a processing container, and modifying the elemental thin film of the substrate with the activated processing gas Mechanism,
A transfer mechanism that allows the reaction vessel and the processing vessel to communicate in the same vacuum state, and transfers the substrate from the reaction vessel to the processing vessel without exposing the substrate to the atmosphere;
A thin film manufacturing apparatus comprising: 前記高密度プラズマ発生機構は２７〜１５００ＭＨｚの範囲に含まれる周波数の電力を供給する高周波電源を含むことを特徴とする請求項９記載の薄膜作製装置。The high-density plasma generating mechanism thin film preparation apparatus according to claim 9 Symbol mounting, characterized in that it comprises a high-frequency power supply for supplying power at a frequency included in the range of 27～1500MHz. 前記第２工程用機構は、前記高密度プラズマを安定させる安定化ガスを導入する安定化ガス導入機構を備えることを特徴とする請求項９記載の薄膜作製装置。The second step for mechanism, the high-density plasma film manufacturing apparatus according to claim 9 Symbol mounting, characterized in that it comprises a stabilizing gas introduction mechanism for introducing a stabilizing gas to stabilize. 前記第２工程用機構の高密度プラズマ発生機構は、内蔵アンテナ型高密度プラズマ源、ヘリコン波励起プラズマ源、ＥＣＲプラズマ源のうちいずれかを備えることを特徴とする請求項９記載の薄膜作製装置。High-density plasma generating mechanism of the second step for mechanism, the built-in antenna type high-density plasma source, a helicon wave excited plasma source, a thin film produced according to claim 9 Symbol mounting, characterized in that it comprises any one of ECR plasma sources apparatus. 気密構造を有し内部に基体を保持する基体ホルダを備えた容器と、この容器内にテトラキスジアルキルアミノチタンを導入する原料導入機構と、前記容器に処理ガスを導入する処理ガス導入機構と、前記容器内を真空に排気する排気機構と、前記容器内に電子密度が１０１０個／ｃｍ３以上の高密度プラズマを発生させる高密度プラズマ 発生機構と、前記容器内にプラズマを発生して前記容器内をクリーニングするクリーニング機構と、前記クリーニングの際に前記基体を前記容器の外に取り出す取出し機構を備え、
前記原料導入機構から供給される前記テトラキスジアルキルアミノチタンの原料ガスによって前記基体ホルダ上の前記基体の表面に窒化チタンを主成分とする素薄膜を作製し、その後前記取出し機構で前記基体を前記容器の外に取出した状態で前記クリーニング機構によって前記容器内をクリーニングし、その後、前記基体を再び前記基体ホルダの上に保持した状態で前記処理ガス導入機構によって供給される前記処理ガスで前記基体の前記素薄膜を改質したことを特徴とする薄膜作製装置。A container having an airtight structure and a substrate holder for holding a substrate therein; a raw material introduction mechanism for introducing tetrakisdialkylaminotitanium into the container; a processing gas introduction mechanism for introducing a processing gas into the container; An exhaust mechanism for evacuating the inside of the container, a high-density plasma generating mechanism for generating high-density plasma with an electron density of 10 10 pieces / cm 3 or more in the container, and generating the plasma in the container A cleaning mechanism for cleaning the inside, and a take-out mechanism for taking out the substrate out of the container during the cleaning,
An elemental thin film containing titanium nitride as a main component is formed on the surface of the substrate on the substrate holder by the tetrakisdialkylaminotitanium source gas supplied from the material introduction mechanism, and then the substrate is transferred to the container by the take-out mechanism. The inside of the container is cleaned by the cleaning mechanism in a state where the substrate is taken out of the substrate, and then the processing gas supplied by the processing gas introduction mechanism is held with the substrate again on the substrate holder. A thin film production apparatus characterized by modifying the elemental thin film. 前記高密度プラズマ発生機構は２７〜１５００ＭＨｚの範囲に含まれる周波数の電力を供給する高周波電源を含むことを特徴とする請求項１３記載の薄膜作製装置。The high-density plasma generating mechanism thin film preparation apparatus according to claim 1 3 Symbol mounting characterized in that it comprises a high-frequency power supply for supplying power at a frequency included in the range of 27～1500MHz. 前記高密度プラズマを安定させる安定化ガスを導入する安定化ガス導入機構を備えることを特徴とする請求項１３記載の薄膜作製装置。The high-density plasma according to claim 1 3 Symbol placement of a thin film manufacturing device, comprising a stabilizing gas introduction mechanism for introducing a stabilizing gas to stabilize the. 前記高密度プラズマ発生機構は、内蔵アンテナ型高密度プラズマ源、ヘリコン波励起プラズマ源、ＥＣＲプラズマ源のうちいずれかを備えることを特徴とする請求項１３記載の薄膜作製装置。The high-density plasma generating mechanism, the built-in antenna type high-density plasma source, a helicon wave excited plasma source, a thin film manufacturing apparatus according to claim 1 3 Symbol mounting, characterized in that it comprises any one of ECR plasma sources.
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