JP4283911B2

JP4283911B2 - Semiconductor manufacturing apparatus and method for forming polyimide film

Info

Publication number: JP4283911B2
Application number: JP19180098A
Authority: JP
Inventors: 正行飯島; 昌敏佐藤; 禎之浮島
Original assignee: Ulvac Inc
Current assignee: Ulvac Inc
Priority date: 1998-07-07
Filing date: 1998-07-07
Publication date: 2009-06-24
Anticipated expiration: 2018-07-07
Also published as: JP2000021868A

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体素子内の層間絶縁膜を蒸着重合により形成するための半導体製造装置およびこの装置を用いるポリイミド膜の形成方法に関する。
【０００２】
【従来の技術】
最近、ＬＳＩの高集積化の進展により層間絶縁膜の低比誘電率化が大きな課題とされており、比誘電率が４以下の層間絶縁膜が要求されるようになっている。例えば、低誘電率を満足させる材料としてフッ素化ポリイミドを用いることが提案されており、蒸着重合法により従来のＣＶＤ法に近い成膜装置で低誘電率のポリイミドをコーティングできるようになった。本発明者等は、蒸着重合で作製した様々なフッ素化ポリイミド材料が２．５以下の比誘電率を有することを見いだしている。
【０００３】
【発明が解決しようとする課題】
しかしながら、かかる従来技術においては、次のような問題があった。すなわち、蒸着重合法に用いるモノマーのうちジアミン成分の蒸気圧が高く、そのため基板への付着確率が小さく、成膜速度を大きくできないということである。なお、ジアミン成分の酸無水物成分との反応性が高ければ、蒸気圧の低い酸無水物成分が基板に付着したとき、ジアミン成分との反応が起こるので、ジアミン成分の蒸気圧が高くても成膜は容易であるが、フッ素化ジアミン成分のような場合は、フッ素化していないジアミン成分に比べ反応性が低いため、成模速度はジアミン成分の付着確率に依存してしまう。
【０００４】
本発明は、このような従来の技術の問題点を解決するためになされたものであり、層間絶縁膜用の高分子膜を効率よく形成するための半導体製造装置およびこの装置を用いて半導体素子内の層間絶縁膜用のポリイミド膜を高い成膜速度で形成するための方法を提供することを目的とするものである。
【０００５】
【課題を解決するための手段】
本発明者等は、前記課題を解決すベく鋭意研究を重ねた結果、基板の表面温度を低くすることにより、従来に比べ数倍以上高い成膜速度が得られることを見いだし、本発明を完成するに至った。
【０００６】
本発明の半導体装置は、ウエハーの出し入れのための室とウエハーの搬送用ロボットを備えたコア室と複数の半導体製造プロセス室とからなり、該プロセス室の少なくとも一室がポリイミド膜の蒸着重合用原料モノマーの蒸発源を有する蒸着重合室である枚葉式の半導体製造装置において、該蒸着重合室が該ウエハーの表面温度を３０℃より低く冷却する手段を備え、各モノマーを基板上に均一に導入するため、その側壁に沿って設けられた熱源により保温されたモノマー混合槽が前記蒸着重合室に設けられ、該モノマー混合槽は、基板側に向かって広がった断面台形状で、混合槽基板側の開口部が基板よりも大きくなっている。この半導体製造装置において、該蒸発源から該蒸着重合室へ導入される該原料モノマーの供給量を制御するための上流側のバルブ及びその下流側の気体流量コントローラーが該蒸着重合室と該原料モノマー蒸発源との間に設けられていてもよい。
【０００７】
また、本発明のポリイミド膜の形成方法は、上記半導体製造装置を用いてポリイミド膜を形成する方法において、基板側の開口部が基板よりも大きく、基板側に向かって広がった断面台形状のモノマー混合槽を有する該蒸着重合室内で、該ウエハー上に該原料モノマーを蒸着重合せしめてポリイミド膜を形成するに際し、該ウエハーの表面温度を３０℃より低く、好ましくは２５℃以下にして蒸着重合を行い、該ウエハー上にポリイミド膜を形成することからなる。この方法はまた、該蒸着重合室内で、該ウエハー上に該原料モノマーを蒸着重合せしめてポリイミド膜を形成するに際し、該蒸着重合室と該原料モノマー蒸発源との間に設けてある上流側のバルブ及びその下流側の気体流量コントローラーによって、該蒸発源で気化された該原料モノマーの供給量を制御して該蒸着重合室へ導入し、該蒸着重合室内のウエハーの表面温度を３０℃より低く、好ましくは２５℃以下にして蒸着重合を行ってもよい。
【０００８】
本発明で用いる前記原料モノマーのうちジアミンモノマー成分としては、例えばＴＦＤＢ、１６ＦＰＤ、１３ＦＰＰＤ、４ＦＭＰＤ、１７ＦＭＰＤ、８ＦＯＤＡ（ＴＦＤＢ：２，２′-ビス（トリフロロメチル）５-４，４′ジアミノビフェニル、１６ＦＰＤ：４，４′-ビス（４-テトラフロロアミノフェノキシ）オクタフロロビフェニル、１３ＦＰＰＤ：２，５-ジアミノトリデカンフロロ-ｎ-ヘキシルベンゼン、４ＦＭＰＤ：テトラフロロ-ｍ-フェニレンジアミン、１７ＦＭＰＤ：５-（パーフロロノネニルオキシ）-１，３-ジアミノベンゼン）、８ＦＯＤＡ：ビス（２，３，５，６-テトラフロロ-４-アミノフェニル）エーテル）を挙げることができる。また、前記原料モノマーのうち酸無水物モノマー成分としては、Ｐ２ＦＤＡ、Ｐ６ＦＤＡ、１０ＦＥＤＡ（Ｐ２ＦＤＡ：１，４-ジフロロ-２，３，５，６-ベンゼンテトラカルボン酸二無水物、Ｐ６ＦＤＡ：１，４-ビス（フロロメチル-２，３，５，６-ベンゼンテトラカルボン酸二無水物、１０ＦＥＤＡ：４，４-ビス[３，４-ジカルボキシリトリフロロフェノキシ]テトラフロロベンゼン二無水物）を挙げることができる。
【０００９】
上記蒸着重合の条件は、一般に、高真空中（１×１０^-3Ｐａ）で両モノマーの組成比が化学量論比になるよう加熱蒸着するものである。ただし、基板温度はモノマーの種類により異なる。
【００１０】
なお、蒸着重合による成膜プロセスにおいては、一般に、原料モノマーの反応性と蒸気圧とが成膜に大きく影響する。反応性が低いモノマー同士の組み合わせでは、基板温度を上げれば、モノマーの反応律速条件で重合が起こり成膜するので、各モノマーの蒸着重合室への導入量を精密に制御する必要はない。しかし、反応性が高く、かつ蒸気圧の低いモノマー同士の組み合わせでは、モノマーの供給律速条件で重合が起こり成膜するので、各モノマーの蒸着重合室への導入量を精密に制御することが必要になる。２種以上のモノマーを使う蒸着重合では、各モノマーの組成比が１：１に近いほど、得られる重合体材料の耐熱性、機械的特性、電気的特性等の物性は向上するが、逆に、組成比がずれるほど物性は低下する。従来の方法では、モノマー供給量と気化温度のみで各モノマーの蒸着重合室への導入量を制御していただけなので、この方法では精密な制御ができ難く、かくして得られた膜の特性がばらつくという欠点があった。しかし、好ましくは、気体流量コントローラーを用いて各モノマーの蒸着重合室への導入量を精密に制御すれば、得られる膜の物性のばらつきは極めて小さくなる。例えば、気体流量コントローラーを使用しないで成膜した膜の物性値のばらつきは平均値±１０％程度であるが、気体流量コントローラーを使用して成膜した膜の物性値のばらつきは平均値±３％程度のように低くなると共に、物性値自体も５〜１０％向上する。
【００１１】
さらに、上記した蒸着重合を実施した場合に、蒸発したモノマーや反応して生成した重合膜やこれらの混合膜が蒸着重合室の内壁面に付着し、成膜操作を繰り返すにつれて目的とする膜の物性が不安定になることがある。この場合、成膜毎に蒸着重合室内に付着したモノマーや高分子膜等を酸素プラズマによりクリーニングすれば、ダストの発生がなく安定した半導体素子が得られる。そのためには、蒸着重合室内に酸素の導入および放電が可能な電極またはアンテナを設ければよい。例えば、蒸着重合室に、クリーニングガスとして酸素または酸素を含むガスを導入するためのガス導入口を設け、かつ装置内部に放電のためのプラズマ用電極を有する構造（ＲＦまたはＤＣ放電）を設け、あるいはまた放電のために、蒸着重合室の内側の壁面に石英製の棒着板を配置し、その棒着板の外側の壁面にアンテナを有する（ヘリコンプラズマ）構造または該蒸着重合室の外側に磁石を配置した構造（ＮＬＤ放電）としてもよい。酸素プラズマの条件は、例えば、酸素流量：約２００ｓｃｃｍ、時間：６０秒/膜厚１μｍ、圧力：０．０５〜１．０Ｔｏｒｒ、ＲＷパワー：１００〜２００Ｗであるのが望ましく、この放電が蒸着重合室全体に行き渡るようにするためには、円形の電極を蒸着重合室から５０ｍｍ以内になるように設置するのが望ましい。また、この蒸着重合室はヒーターまたは温媒によって１５０℃以上に加熱可能なように構成し、これによりかかる膜が該室の内壁面に付着し難いようにする。
【００１２】
【発明の実施の形態】
以下、本発明の好ましい実施の形態を図面を参照して詳細に説明する。図１は、本発明の半導体製造装置の一例の概略構成を示すものであり、図２は図１の一部を構成する蒸着重合室の一例の概略構成を示すものであり、図３は図１の一部を構成する蒸着重合室の別の一例の概略構成を示すものである。
【００１３】
図１に示すように、この装置においては、シリコン基板等の基板の搬送用ロボットが組み込まれたコア室１、シリコン基板等の基板のＬ／ＵＬ室２、蒸着重合室（第１室）３、加熱処理室（第２室）４、およびアルミスパッタ室（第３室）５が設けられており、コア室１を中心として、このコア室にＬ／ＵＬ室２、第１室３、第２室４、および第３室５がそれぞれ、ゲートバルブ７を介して連結されるように構成されている。なお、これらの室は、真空ポンプ等の真空排気系（図示せず）に連結されている。コア室１に設けられた既知の基板搬送用ロボットは、基板を、コア室を軸にしてＬ／ＵＬ室２、蒸着重合室３、加熱処理室４、アルミスパッタ室５等からまたこれらの各室に搬入・搬出可能なように設定されており、Ｌ／ＵＬ室からこれらの各室にまたこれらの室相互間で自由に搬送可能なようになっている。
【００１４】
また、図２および３に示すように、蒸着重合室３には、２種類の原料モノマーＡ、Ｂの供給源が気化（蒸発）器１１ａ、１１ｂと所望により気体流量コントローラー１２ａ、１２ｂ（図３）を介して配置されており、蒸着重合室へ気化された原料モノマーを導入できるようになっている。各モノマー供給源のハウジング１３ａ、１３ｂにはそれぞれ、モノマーＡ、Ｂのモノマー容器１４ａ、１４ｂが設けられ、また各容器の周りにはそれぞれに各モノマーを加熱するためのヒーターのような気化用熱源１５ａ、１５ｂが設けられている。供給源（気化器１１ａ、１１ｂ）、随時気体流量コントローラー１２ａ、１２ｂ、および蒸着重合室３を連結し、かつ蒸着重合室へ各モノマーを導入するための導入管１６ａ、１６ｂは、ヒーター等の熱源Ｈで温度制御可能なようになっている。また、導入管１６ａ、１６ｂの蒸着重合室３への連結部と基板支え部材１７上に載置された基板１８との間には、各モノマーが基板上に均一に供給できるようにするためヒーター等の熱源Ｈにより保温されたモノマー混合槽１９が配置されている。
【００１５】
各導入管１６ａ、１６ｂの管路の途中にはバルブ２０ａ、２０ｂが配置されており、蒸着重合膜形成時にこれらのバルブを開閉することにより膜厚を制御できる。基板支え部材１７は冷媒系（図示せず）に連結され、基板１８の表面がこの冷媒手段によって所定の温度に冷却可能なようになっている。
【００１６】
上記装置を用いて基板１８上に層間絶縁膜を成膜する場合には、基板をコア室１を経由してＬ／ＵＬ室２から蒸着重合室３へ移動した後バルブ２０ａ、２０ｂを開け、所定の時間の間成膜プロセスを実施し、次いでバルブ２０ａ、２０ｂを閉め、基板を加熱処理室４に搬送する。この加熱処理室内で、所定の条件下熱処理を行う。一般に、熱処理は、昇温速度１０℃／分で４００℃まで加熱し、１時間この温度に保持し、最後に自然冷却するようにして行われる。雰囲気としては、高真空中または不活性ガス中のような条件下で行われる。また、必要に応じ、基板をアルミスパッタ５室へ搬送して、一般に、Ａｒ：１０００ｓｃｃｍ、１×１０^-2Ｐａ、ＲＦパワー：２ＫＷ、基板バイアスなし、成膜速度（ｒａｔｅ）：５０Å／ｓｅｃ、膜厚：２００ｎｍのような条件下でアルミ電極を成膜することもできる。
【００１７】
以下、本発明の装置を用いてポリイミド膜からなる半導体素子の層間絶縁膜を形成する工程の一つの実施の形態を示す。
【００１８】
まず、ポリイミド膜を形成するための半導体基板として、基板表面に形成され、かつ所定の位置に窓開けがされたシリコン熱酸化膜と、その上に成膜されかつパターニングが施された第１層目の配線とを有する、例えばＳｉからなる基板を用意する。この基板の表面に、上述の蒸着法によってポリイミド膜を所望の厚みに全面成膜して層間絶縁膜を形成する。次いで、この層間絶縁膜の表面に所定のパターニングが施されたレジスト膜を形成し、通常のドライエッチングを行ってレジスト膜の窓開け部分に露出した層間絶縁膜を除去する。そして、上述のレジスト膜を除去した後、配線薄膜を全面成膜し、パターニングを施して第２層目の配線を形成する。このようにすることにより、層間絶縁膜が除去された窓開け部分で、第１層目の配線と第２層目の配線とが電気的に接続され、その結果、多層配線を有する半導体素子を得ることができる。
【００１９】
本実施の形態によれば、低比誘電率化したポリイミド膜によって層間絶縁膜を構成しているので、第１層目の配線と第２層目の配線との間で形成されるコンデンサーの容量が小さくなり、半導体素子の動作速度を向上させることが可能になる。
【００２０】
【実施例】
以下、本発明の具体的な実施例を比較例とともに説明する。
【００２１】
（実施例１）
図１および２に示す装置を用いて次のようにして基板上にポリイミド膜を形成した。まず、コア室１に設けられた基板搬送用ロボットを用いて、コア室を経由してＬ／ＵＬ室２から導電率が０．０２Ωｃｍである６インチ寸法のシリコン基板１８を真空蒸着室３へ搬送し、冷媒を用いてこの基板表面を１５℃に冷却した後、ここでポリイミド膜を蒸着重合した。ポリイミド膜を形成するための原料モノマーとして、１７ＦＭＰＤとＰ２ＦＤＡとを用い、これらをそれぞれ気化器１１ａ、１１ｂ内の容器１４ａ、１４ｂへ入れ、熱源（１５ａ、１５ｂ）を用いて蒸発させた。１７ＦＭＰＤは６０．０℃で、またＰ２ＦＤＡは１３０．０℃の温度で蒸発させ、各モノマーの供給量を制御した。得られた各蒸気をそれぞれ導入管１６ａ、１６ｂを通し、その一定量をモノマー混合槽１９を経て蒸着重合室３に供給し、基板１８上で蒸着重合せしめた。この場合、図３に示すように、所望により気体流量コントローラー１２ａ、１２ｂを用いて、各蒸気の一定量（例えば、１００ｓｃｃｍ）を蒸着重合室へ３供給してもよい。なお、モノマーの組成比は化学量論比で１：１となるように制御し、また導入管１６ａ、１６ｂを通過する間にモノマー温度が下がらないように導入管を所定の温度に保温した。この蒸着重合条件は、到達圧力１×１０^-4Ｐａ、蒸着中圧力１×１０^-2Ｐａであった。
【００２２】
蒸着重合室３で成膜後、得られた基板を基板搬送用ロボットを用いてコア室１を経由して加熱処理室４へ搬送し、熱処理を行った。この熱処理は、昇温速度１０℃／ｍｉｎで４００℃まで加熱することによって行った。この時点での膜厚は５００ｎｍであった。
【００２３】
上記熱処理後、基板をアルミスパッタ室６内に搬送し、基板上にアルミ電極をスパッタにより２００ｎｍの膜厚で形成し、比誘電率測定用の素子を作製した。この素子についての比誘電率を測定したところ、２．５５であった。この場合、比誘電率の値は、横河ヒューレットパッカード社製のマルチ・フリケンシＬＣＲメータ（モデル４２７５Ａ）を使用して静電容量Ｃを測定し、計算によって求めた。
【００２４】
（比較例１）
比較のために、実施例１における蒸着重合中の基板表面の温度１５℃を３０℃にしたことを除いて、実施例１の操作を繰り返した。得られた素子の膜厚は１５０ｎｍであり、比誘電率は２．６０であった。
【００２５】
上記実施例及び比較例の結果、基板温度１５℃で蒸着重合を行った場合の成膜速度は３０ｎｍ／ｍｉｎであり、３０℃の場合は５ｎｍ／ｍｉｎ以下であり、成膜速度に基板温度が影響することがわかった。
【００２６】
（実施例２）
原料モノマーとして、実施例１における１７ＦＭＰＤおよびＰ２ＦＤＡの代わりに１３ＦＰＤおよびＰ２ＦＤＡを用い、１３ＦＰＤは５５．０＋０．１℃、Ｐ２ＦＤＡは１３０＋０．１℃の温度で蒸発させ、各モノマーの供給量を制御したこと、また蒸着重合室内での基板表面の温度を２５℃にしたことを除いて、実施例１の操作を繰り返した。得られた素子の膜厚は２００ｎｍであり、比誘電率は２．７２であった。本実施例における成膜速度は１５ｎｍ／ｍｉｎであった。
【００２７】
【発明の効果】
本発明の半導体製造装置によれば、蒸着重合室には、層間絶縁膜用の高分子膜を蒸着重合する際のウエハーの表面を冷却するための手段が設けられてあるので、かかる高分子膜を効率よく形成することができるようになっている。
【００２８】
また、かかる半導体製造装置を用いて、蒸着重合室内でウエハー上に原料モノマーを蒸着重合せしめて層間絶縁膜を形成する際に、該ウエハーの表面温度を３０℃より低くして蒸着重合を行うので、ポリイミド膜を高い成膜速度で容易に得ることができる。
【図面の簡単な説明】
【図１】本発明の半導体製造装置の一例の概略構成を示す模式的平面図。
【図２】本発明の半導体製造装置の一部を構成する蒸着重合室の一例の概略構成を示す模式的断面図。
【図３】本発明の半導体製造装置の一部を構成する蒸着重合室の別の一例の概略構成を示す模式的断面図。
【符号の説明】
１コア室２Ｌ／ＵＬ室
３蒸着重合室４加熱処理室
５アルミスパッタ室６ゲートバルブ
１１ａ、１１ｂ気化器１２ａ、１２ｂ気体流量コントローラー
１３ａ、１３ｂハウジング１４ａ、１４ｂモノマー容器
１５ａ、１５ｂ気化用熱源１６ａ、１６ｂ導入管
１７基板支え部材１８基板
１９モノマー混合槽２０ａ、２０ｂバルブ
Ａ、ＢモノマーＨ熱源[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor manufacturing apparatus for forming an interlayer insulating film in a semiconductor element by vapor deposition polymerization, and a method for forming a polyimide film using this apparatus.
[0002]
[Prior art]
Recently, with the progress of higher integration of LSIs, the reduction of the relative dielectric constant of the interlayer insulating film has been a major issue, and an interlayer insulating film having a relative dielectric constant of 4 or less has been required. For example, it has been proposed to use fluorinated polyimide as a material that satisfies a low dielectric constant, and it has become possible to coat polyimide with a low dielectric constant by a deposition apparatus close to the conventional CVD method by vapor deposition polymerization. The present inventors have found that various fluorinated polyimide materials prepared by vapor deposition polymerization have a relative dielectric constant of 2.5 or less.
[0003]
[Problems to be solved by the invention]
However, this conventional technique has the following problems. That is, the vapor pressure of the diamine component among the monomers used in the vapor deposition polymerization method is high, so that the probability of adhesion to the substrate is small and the film formation rate cannot be increased. If the reactivity of the diamine component with the acid anhydride component is high, the reaction with the diamine component occurs when the acid anhydride component with a low vapor pressure adheres to the substrate, so even if the vapor pressure of the diamine component is high. Film formation is easy, but in the case of a fluorinated diamine component, since the reactivity is lower than that of a non-fluorinated diamine component, the patterning speed depends on the adhesion probability of the diamine component.
[0004]
The present invention has been made in order to solve such problems of the prior art, and a semiconductor manufacturing apparatus for efficiently forming a polymer film for an interlayer insulating film, and a semiconductor element using this apparatus It is an object of the present invention to provide a method for forming a polyimide film for an inner interlayer insulating film at a high film formation rate.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that a film formation rate several times higher than the conventional one can be obtained by lowering the surface temperature of the substrate. It came to be completed.
[0006]
The semiconductor device of the present invention comprises a chamber for loading / unloading a wafer, a core chamber having a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, and at least one of the process chambers is for vapor deposition polymerization of a polyimide film in the semiconductor manufacturing apparatus of the single wafer is deposited polymer chamber having a vapor source of the raw material monomer, comprising means for the vapor deposition polymerization chamber is cooled below 30 ° C. the surface temperature of the wafer uniformly each monomer on the substrate In order to introduce, a monomer mixing tank kept warm by a heat source provided along the side wall thereof is provided in the vapor deposition polymerization chamber, and the monomer mixing tank has a trapezoidal cross section extending toward the substrate side, and a mixing tank substrate The opening on the side is larger than the substrate. In this semiconductor manufacturing apparatus, an upstream valve for controlling the supply amount of the raw material monomer introduced from the evaporation source to the vapor deposition polymerization chamber and a gas flow rate controller on the downstream side thereof are the vapor deposition polymerization chamber and the raw material monomer. It may be provided between the evaporation source.
[0007]
In addition, the polyimide film forming method of the present invention is a method of forming a polyimide film using the semiconductor manufacturing apparatus described above, wherein the opening on the substrate side is larger than the substrate, and the monomer having a trapezoidal cross section extending toward the substrate side. In forming the polyimide film by vapor deposition polymerization of the raw material monomer on the wafer in the vapor deposition polymerization chamber having a mixing tank, the surface polymerization temperature of the wafer is lower than 30 ° C., preferably 25 ° C. or lower. And forming a polyimide film on the wafer. This method also includes an upstream side provided between the vapor deposition polymerization chamber and the raw material monomer evaporation source when the raw material monomer is vapor deposited and polymerized on the wafer in the vapor deposition polymerization chamber to form a polyimide film . The supply amount of the raw material monomer vaporized by the evaporation source is controlled by a valve and a gas flow rate controller on the downstream side thereof, and introduced into the vapor deposition polymerization chamber, and the surface temperature of the wafer in the vapor deposition polymerization chamber is lower than 30 ° C. The vapor deposition polymerization may be performed preferably at 25 ° C. or lower.
[0008]
Among the raw material monomers used in the present invention, examples of the diamine monomer component include TFDB, 16FPD, 13FPPD, 4FMPD, 17FMPD, 8FODA (TFDB: 2,2′-bis (trifluoromethyl) 5-4,4′diaminobiphenyl, 16FPD: 4,4′-bis (4-tetrafluoroaminophenoxy) octafluorobiphenyl, 13FPPD: 2,5-diaminotridecanefluoro-n-hexylbenzene, 4FMPD: tetrafluoro-m-phenylenediamine, 17FMPD: 5- ( Perfluorononenyloxy) -1,3-diaminobenzene), 8FODA: bis (2,3,5,6-tetrafluoro-4-aminophenyl) ether) . Among the raw material monomers, acid anhydride monomer components include P2FDA, P6FDA, 10FEDA (P2FDA: 1,4-difluoro-2,3,5,6-benzenetetracarboxylic dianhydride, P6FDA: 1,4 -Bis (fluoromethyl-2,3,5,6-benzenetetracarboxylic dianhydride, 10FEDA: 4,4-bis [3,4-dicarboxytritrifluorophenoxy] tetrafluorobenzene dianhydride) it can.
[0009]
The conditions for the above-mentioned vapor deposition polymerization are generally those in which heat deposition is performed in a high vacuum (1 × 10 ⁻³ Pa) so that the composition ratio of both monomers becomes a stoichiometric ratio. However, the substrate temperature varies depending on the type of monomer.
[0010]
In the film formation process by vapor deposition polymerization, generally, the reactivity of the raw material monomer and the vapor pressure greatly affect the film formation. In the case of a combination of monomers having low reactivity, if the substrate temperature is increased, polymerization occurs under the reaction rate-determining condition of the monomer to form a film, so that it is not necessary to precisely control the amount of each monomer introduced into the vapor deposition polymerization chamber. However, in the case of a combination of monomers with high reactivity and low vapor pressure, polymerization occurs and film formation occurs under the rate-determining condition of monomer supply, so it is necessary to precisely control the amount of each monomer introduced into the vapor deposition polymerization chamber. become. In vapor deposition polymerization using two or more monomers, the closer the composition ratio of each monomer is to 1: 1, the better the physical properties of the resulting polymer material, such as heat resistance, mechanical properties, and electrical properties. The physical properties decrease as the composition ratio shifts. In the conventional method, since the amount of each monomer introduced into the vapor deposition polymerization chamber is controlled only by the monomer supply amount and the vaporization temperature, it is difficult to perform precise control by this method, and the properties of the film thus obtained vary. There were drawbacks. However, preferably, if the amount of each monomer introduced into the vapor deposition polymerization chamber is precisely controlled using a gas flow rate controller, the variation in the physical properties of the resulting film is extremely small. For example, the dispersion of the physical property value of the film formed without using the gas flow controller is about ± 10% on the average, but the dispersion of the physical property value of the film formed using the gas flow controller is on the average value ± 3. %, The physical property value itself is improved by 5 to 10%.
[0011]
Further, when the above-described vapor deposition polymerization is carried out, the evaporated monomer, the polymer film formed by reaction, or a mixed film thereof adheres to the inner wall surface of the vapor deposition polymerization chamber, and as the film formation operation is repeated, The physical properties may become unstable. In this case, if a monomer, a polymer film, or the like attached in the vapor deposition polymerization chamber is cleaned with oxygen plasma for each film formation, a stable semiconductor element without dust generation can be obtained. For this purpose, an electrode or an antenna capable of introducing and discharging oxygen may be provided in the vapor deposition polymerization chamber. For example, in the vapor deposition polymerization chamber, a gas inlet for introducing oxygen or a gas containing oxygen as a cleaning gas is provided, and a structure (RF or DC discharge) having a plasma electrode for discharge inside the apparatus is provided, Alternatively, for discharge, a quartz rod attachment plate is disposed on the inner wall surface of the vapor deposition polymerization chamber, and an antenna is provided on the outer wall surface of the rod attachment plate (helicon plasma) or outside the vapor deposition polymerization chamber. It is good also as a structure (NLD discharge) which has arrange | positioned the magnet. The oxygen plasma conditions are preferably, for example, oxygen flow rate: about 200 sccm, time: 60 seconds / film thickness 1 μm, pressure: 0.05 to 1.0 Torr, RW power: 100 to 200 W, and this discharge is vapor deposition polymerization. In order to reach the entire chamber, it is desirable to install a circular electrode so that it is within 50 mm from the vapor deposition polymerization chamber. In addition, the vapor deposition polymerization chamber is configured so that it can be heated to 150 ° C. or higher by a heater or a heating medium, so that the film hardly adheres to the inner wall surface of the chamber.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of an example of the semiconductor manufacturing apparatus of the present invention, FIG. 2 shows a schematic configuration of an example of a vapor deposition polymerization chamber constituting a part of FIG. 1, and FIG. 1 shows a schematic configuration of another example of a vapor deposition polymerization chamber constituting a part of 1.
[0013]
As shown in FIG. 1, in this apparatus, a core chamber 1 in which a robot for transferring a substrate such as a silicon substrate is incorporated, an L / UL chamber 2 for a substrate such as a silicon substrate, and a vapor deposition polymerization chamber (first chamber) 3. , A heat treatment chamber (second chamber) 4 and an aluminum sputtering chamber (third chamber) 5 are provided, with the core chamber 1 as the center, the L / UL chamber 2, the first chamber 3, Each of the two chambers 4 and the third chamber 5 is configured to be connected via a gate valve 7. These chambers are connected to an evacuation system (not shown) such as a vacuum pump. A known substrate transfer robot provided in the core chamber 1 is configured to transfer a substrate from the L / UL chamber 2, the vapor deposition polymerization chamber 3, the heat treatment chamber 4, the aluminum sputtering chamber 5 and the like around the core chamber. It is set so that it can be carried into and out of the chamber, and can be freely transported from the L / UL chamber to these chambers and between these chambers.
[0014]
Also, as shown in FIGS. 2 and 3, in the vapor deposition polymerization chamber 3, two types of raw material monomers A and B are supplied with vaporizers (evaporators) 11a and 11b and optionally with gas flow controllers 12a and 12b (FIG. 3). ) Through which the vaporized raw material monomer can be introduced into the vapor deposition polymerization chamber. The monomer supply housings 13a and 13b are provided with monomer containers 14a and 14b for monomers A and B, respectively, and a vaporization heat source such as a heater for heating each monomer around each container. 15a and 15b are provided. The supply pipes (vaporizers 11a and 11b), the gas flow rate controllers 12a and 12b as needed, and the vapor deposition polymerization chamber 3, and the introduction pipes 16a and 16b for introducing the monomers into the vapor deposition polymerization chamber are heat sources such as heaters. The temperature can be controlled with H. In addition, a heater is provided between the connecting portion of the introduction pipes 16a and 16b to the vapor deposition polymerization chamber 3 and the substrate 18 placed on the substrate support member 17 so that each monomer can be uniformly supplied onto the substrate. A monomer mixing tank 19 kept warm by a heat source H such as the like is disposed.
[0015]
Valves 20a and 20b are arranged in the middle of the pipes of the introduction pipes 16a and 16b, and the film thickness can be controlled by opening and closing these valves when forming the vapor deposition polymer film. The substrate support member 17 is connected to a refrigerant system (not shown), and the surface of the substrate 18 can be cooled to a predetermined temperature by the refrigerant means.
[0016]
When an interlayer insulating film is formed on the substrate 18 using the above apparatus, the substrate is moved from the L / UL chamber 2 to the vapor deposition polymerization chamber 3 via the core chamber 1, and then the valves 20a and 20b are opened. A film forming process is performed for a predetermined time, and then the valves 20 a and 20 b are closed, and the substrate is transferred to the heat treatment chamber 4. Heat treatment is performed under predetermined conditions in the heat treatment chamber. In general, the heat treatment is performed by heating to 400 ° C. at a rate of temperature increase of 10 ° C./min, holding at this temperature for 1 hour, and finally naturally cooling. The atmosphere is performed under conditions such as high vacuum or inert gas. Further, if necessary, the substrate is transferred to the aluminum sputtering chamber 5, and generally, Ar: 1000 sccm, 1 × 10 ⁻² Pa, RF power: ² KW, no substrate bias, film formation rate (rate): 50 Å / sec, Film thickness: An aluminum electrode can also be formed under conditions such as 200 nm.
[0017]
Hereinafter, one embodiment of a process of forming an interlayer insulating film of a semiconductor element made of a polyimide film using the apparatus of the present invention will be described.
[0018]
First, as a semiconductor substrate for forming a polyimide film, a silicon thermal oxide film formed on the substrate surface and having a window opened at a predetermined position, and a first layer formed thereon and patterned A substrate made of, for example, Si having an eye wiring is prepared. On the surface of this substrate, a polyimide film is formed on the entire surface to a desired thickness by the above-described vapor deposition method to form an interlayer insulating film. Next, a resist film subjected to predetermined patterning is formed on the surface of the interlayer insulating film, and normal dry etching is performed to remove the interlayer insulating film exposed at the window opening portion of the resist film. Then, after removing the resist film, a wiring thin film is formed on the entire surface and patterned to form a second-layer wiring. By doing so, the first layer wiring and the second layer wiring are electrically connected at the window opening portion where the interlayer insulating film is removed, and as a result, a semiconductor element having a multilayer wiring is obtained. Obtainable.
[0019]
According to the present embodiment, since the interlayer insulating film is constituted by the polyimide film having a low relative dielectric constant, the capacitance of the capacitor formed between the first layer wiring and the second layer wiring And the operating speed of the semiconductor element can be improved.
[0020]
【Example】
Hereinafter, specific examples of the present invention will be described together with comparative examples.
[0021]
Example 1
A polyimide film was formed on the substrate using the apparatus shown in FIGS. 1 and 2 as follows. First, using a substrate transfer robot provided in the core chamber 1, a 6-inch silicon substrate 18 having a conductivity of 0.02 Ωcm is transferred from the L / UL chamber 2 to the vacuum deposition chamber 3 via the core chamber. After transporting and cooling the substrate surface to 15 ° C. using a refrigerant, a polyimide film was vapor deposited and polymerized here. As raw material monomers for forming the polyimide film, 17FMPD and P2FDA were used, put into containers 14a and 14b in vaporizers 11a and 11b, respectively, and evaporated using heat sources (15a and 15b). 17FMPD was evaporated at a temperature of 60.0 ° C. and P2FDA was evaporated at a temperature of 130.0 ° C. to control the supply amount of each monomer. The obtained vapors were passed through the introduction pipes 16a and 16b, respectively, and a certain amount thereof was supplied to the vapor deposition polymerization chamber 3 through the monomer mixing tank 19, and vaporized and polymerized on the substrate 18. In this case, as shown in FIG. 3, a certain amount (for example, 100 sccm) of each vapor may be supplied to the vapor deposition polymerization chamber by using the gas flow rate controllers 12a and 12b as desired. The monomer composition ratio was controlled so that the stoichiometric ratio was 1: 1, and the introduction tube was kept at a predetermined temperature so that the monomer temperature did not drop while passing through the introduction tubes 16a and 16b. The vapor deposition polymerization conditions were an ultimate pressure of 1 × 10 ⁻⁴ Pa and a vapor deposition pressure of 1 × 10 ⁻² Pa.
[0022]
After film formation in the vapor deposition polymerization chamber 3, the obtained substrate was transferred to the heat treatment chamber 4 via the core chamber 1 using a substrate transfer robot and subjected to heat treatment. This heat treatment was performed by heating to 400 ° C. at a temperature rising rate of 10 ° C./min. The film thickness at this time was 500 nm.
[0023]
After the heat treatment, the substrate was transferred into the aluminum sputtering chamber 6 and an aluminum electrode was formed on the substrate with a film thickness of 200 nm by sputtering to produce an element for measuring the relative dielectric constant. The relative dielectric constant of this device was measured and found to be 2.55. In this case, the value of the dielectric constant was obtained by calculating the capacitance C using a multi-frequency LCR meter (model 4275A) manufactured by Yokogawa Hewlett-Packard Company.
[0024]
(Comparative Example 1)
For comparison, the operation of Example 1 was repeated except that the temperature of 15 ° C. on the substrate surface during vapor deposition polymerization in Example 1 was changed to 30 ° C. The obtained device had a film thickness of 150 nm and a relative dielectric constant of 2.60.
[0025]
As a result of the above examples and comparative examples, the film formation rate when vapor deposition polymerization is performed at a substrate temperature of 15 ° C. is 30 nm / min, and at 30 ° C., it is 5 nm / min or less. It turns out that it affects.
[0026]
(Example 2)
As the raw material monomer, 13FPD and P2FDA were used instead of 17FMPD and P2FDA in Example 1, 13FPD was evaporated at a temperature of 55.0 + 0.1 ° C, P2FDA was evaporated at a temperature of 130 + 0.1 ° C, and the supply amount of each monomer was controlled. The operation of Example 1 was repeated except that the temperature of the substrate surface in the vapor deposition polymerization chamber was 25 ° C. The film thickness of the obtained device was 200 nm, and the relative dielectric constant was 2.72. The deposition rate in this example was 15 nm / min.
[0027]
【The invention's effect】
According to the semiconductor manufacturing apparatus of the present invention, the vapor deposition polymerization chamber is provided with means for cooling the surface of the wafer when performing vapor deposition polymerization of the polymer film for the interlayer insulating film. Can be formed efficiently.
[0028]
Further, when the interlayer insulating film is formed by vapor deposition polymerization of the raw material monomer on the wafer in the vapor deposition polymerization chamber using such a semiconductor manufacturing apparatus, the vapor deposition polymerization is performed with the surface temperature of the wafer lower than 30 ° C. A polyimide film can be easily obtained at a high film formation rate.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing a schematic configuration of an example of a semiconductor manufacturing apparatus according to the present invention.
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of an example of a vapor deposition polymerization chamber constituting a part of the semiconductor manufacturing apparatus of the present invention.
FIG. 3 is a schematic cross-sectional view showing a schematic configuration of another example of a vapor deposition polymerization chamber constituting a part of the semiconductor manufacturing apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Core chamber 2 L / UL chamber 3 Deposition polymerization chamber 4 Heat processing chamber 5 Aluminum sputter chamber 6 Gate valve 11a, 11b Vaporizer 12a, 12b Gas flow rate controller 13a, 13b Housing 14a, 14b Monomer container 15a, 15b Vaporization heat source 16a , 16b Introduction pipe 17 Substrate support member 18 Substrate 19 Monomer mixing tank 20a, 20b Valve A, B Monomer H Heat source

Claims

The chamber comprises a chamber for loading and unloading a wafer, a core chamber equipped with a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, and at least one of the process chambers has an evaporation source of a raw material monomer for vapor deposition polymerization of a polyimide film. In a single wafer type semiconductor manufacturing apparatus that is a vapor deposition polymerization chamber,
The vapor deposition polymerization chamber has means for cooling the surface temperature of the wafer below 30 ° C., and in order to uniformly introduce each monomer onto the substrate, a monomer mixing tank kept warm by a heat source provided along the side wall thereof A semiconductor manufacturing apparatus provided in the vapor deposition polymerization chamber, wherein the monomer mixing tank has a trapezoidal cross section extending toward the substrate side, and an opening on the mixing tank substrate side is larger than the substrate.

The chamber comprises a chamber for loading and unloading a wafer, a core chamber equipped with a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, and at least one of the process chambers has an evaporation source of a raw material monomer for vapor deposition polymerization of a polyimide film. In a single wafer type semiconductor manufacturing apparatus that is a vapor deposition polymerization chamber,
An upstream valve for controlling a supply amount of the raw material monomer introduced from the evaporation source to the vapor deposition polymerization chamber and a gas flow rate controller on the downstream side are provided between the vapor deposition polymerization chamber and the raw material monomer evaporation source. The vapor deposition polymerization comprising a monomer mixing tank having a trapezoidal cross section that is provided and kept warm by a heat source to uniformly introduce each monomer onto the substrate , and the opening on the substrate side is larger than the substrate and spreads toward the substrate side A semiconductor manufacturing apparatus, wherein the chamber includes means for cooling the surface temperature of the wafer to less than 30 ° C.

The chamber comprises a chamber for loading and unloading a wafer, a core chamber equipped with a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, and at least one of the process chambers has an evaporation source of a raw material monomer for vapor deposition polymerization of a polyimide film. In a single wafer type semiconductor manufacturing apparatus that is a vapor deposition polymerization chamber,
An upstream valve for limiting the amount of the raw material monomer introduced from the evaporation source to the evaporation polymerization chamber and a gas flow rate controller on the downstream side are provided between the vapor deposition polymerization chamber and the raw material monomer evaporation source. The vapor deposition polymerization chamber is provided with means for cooling the surface temperature of the wafer below 30 ° C., and is kept warm by a heat source provided along the side wall thereof in order to uniformly introduce each monomer onto the substrate. A monomer mixing tank is provided in the vapor deposition polymerization chamber, the monomer mixing tank has a trapezoidal cross section extending toward the substrate side, and the opening on the mixing tank substrate side is larger than the substrate. Semiconductor manufacturing equipment.

A vapor deposition polymerization chamber comprising a chamber for loading and unloading a wafer, a core chamber equipped with a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, wherein at least one of the process chambers has an evaporation source of a raw material monomer for vapor deposition polymerization In order to introduce each monomer uniformly onto the substrate into the vapor deposition polymerization chamber, there is provided a single wafer type semiconductor manufacturing apparatus provided with a monomer mixing tank kept warm by a heat source provided along its side wall. In the method of forming a polyimide film using:
A polyimide film is formed by vapor deposition polymerization of the raw material monomer on the wafer in the vapor deposition polymerization chamber having a trapezoidal monomer mixing tank having an opening on the substrate side larger than the substrate and extending toward the substrate side. In this case, the polyimide film is formed by performing vapor deposition polymerization with the surface temperature of the wafer lower than 30 ° C. to form a polyimide film on the wafer.

A vapor deposition polymerization chamber comprising a chamber for loading and unloading a wafer, a core chamber equipped with a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, wherein at least one of the process chambers has an evaporation source of a raw material monomer for vapor deposition polymerization In order to introduce each monomer uniformly onto the substrate into the vapor deposition polymerization chamber, there is provided a single wafer type semiconductor manufacturing apparatus provided with a monomer mixing tank kept warm by a heat source provided along its side wall. In the method of forming a polyimide film using:
A polyimide film is formed by vapor deposition polymerization of the raw material monomer on the wafer in the vapor deposition polymerization chamber having a trapezoidal monomer mixing tank having an opening on the substrate side larger than the substrate and extending toward the substrate side. In this case, the supply amount of the raw material monomer vaporized in the evaporation source is controlled by an upstream valve provided between the vapor deposition polymerization chamber and the raw material monomer evaporation source and a gas flow rate controller on the downstream side. A method for forming a polyimide film, comprising introducing into the vapor deposition polymerization chamber, performing vapor deposition polymerization with a surface temperature of the wafer in the vapor deposition polymerization chamber being lower than 30 ° C., and forming a polyimide film on the wafer.

Among the raw material monomers, as diamine monomer components, TFDB, 16FPD, 13FPPD, 4FMPD, 17FMPD, 8FODA (TFDB: 2,2′-bis (trifluoromethyl) 5-4,4′diaminobiphenyl, 16FPD: 4,4 ′ -Bis (4-tetrafluoroaminophenoxy) octafluorobiphenyl, 13FPPD: 2,5-diaminotridecanefluoro-n-hexylbenzene, 4FMPD: tetrafluoro-m-phenylenediamine, 17FMPD: 5- (perfluorononenyloxy) 6. The method for forming a polyimide film according to claim 4 , wherein (-1,3-diaminobenzene), 8FODA: bis (2,3,5,6-tetrafluoro-4-aminophenyl) ether) is used.

Among the raw material monomers, P2FDA, P6FDA, 10FEDA (P2FDA: 1,4-difluoro-2,3,5,6-benzenetetracarboxylic dianhydride, P6FDA: 1,4-bis ( Fluoromethyl-2,3,5,6-benzenetetracarboxylic dianhydride, 10FEDA: 4,4-bis [3,4-dicarboxytritrifluorophenoxy] tetrafluorobenzene dianhydride) The formation method of the polyimide film in any one of Claims 4-6 .