JP2004349370A

JP2004349370A - Plasma processing apparatus and method

Info

Publication number: JP2004349370A
Application number: JP2003143033A
Authority: JP
Inventors: Seiji Nakajima; 誠二中嶋; Yuji Murashima; 祐二村嶋
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2003-05-21
Filing date: 2003-05-21
Publication date: 2004-12-09
Anticipated expiration: 2023-05-21
Also published as: JP4179047B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for plasma processing which stably sputter without exposing a substrate except a substrate to be treated with a plasma even when previous sputtering is finished and a movable shutter is retracted. <P>SOLUTION: The apparatus for plasma processing includes: a movable type substrate holder which can hold at least two or more substrates in a container for forming a plasma processing chamber; a target formed of a thin film material formed on the substrate; a movable type shutter mechanism between the substrate and the target; and an adhesion preventive plate formed of a double metal plate in which a distance between opposed surfaces is the thickness or more of a sheath at least at one end of a part to generate a plasma in the space formed of the substrate, the target, and the adhesion preventive plate. At least two or more thin films each containing the target material as a component on the substrate are continuously formed by sputtering thereby. The movable shutter is a floating potential. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、スパッタリングにより薄膜を形成するためのプラズマ処理方法および装置に関するものである。
【０００２】
【従来の技術】
半導体集積回路（以下「ＩＣ」と称す）の製造工程では誘電体の成膜が種々行われる。その目的は、例えば層間絶縁膜、エッチングや選択的なイオン注入や選択的な電極の形成のためのマスク、パッシベーション、キャパシタの誘電体膜等である。目的により材質やプラズマ処理方法が選ばれる。たとえば、ＣＶＤ、ドライエッチング、スパッタリング等種々用いられている。近年ＩＣの小型化のためにキャパシタの誘電体膜にチタン酸バリウムストロンチウム（ＢＳＴ）やチタン酸ストロンチウム（ＳＴＯ）等の高誘電体物質のプラズマ処理を行うことが検討されている。さらにセンサやアクチュエータ、不揮発性メモリデバイス用にチタン酸ジルコン酸鉛（ＰＺＴ）、ストロンチウムビスマスタンタレート（ＳＢＴ）といった強誘電体物質のプラズマ処理も検討されている。
【０００３】
従来のスパッタリングを行うプラズマ処理装置を、図面を参照して説明する。図５は複数の基板を連続処理可能なスパッタ装置を概念的に示す縦断面図である。従来のスパッタリング装置は真空引き可能な真空容器４１でスパッタ室を形成し、スパッタ室の下方にはターゲット４８が下部電極４５に固定保持される。下部電極４５は容器４１とは電気的に絶縁されている。そして下部電極４５はターゲット４８の温度が上昇するのを防ぐために水冷機構を内蔵するが図示を略している。
【０００４】
そして、スパッタ室の上方には可動式基板保持機構４２が下部電極４５に対向して平行に配置される。そして、この可動式基板保持機構４２は真空容器４１と電気的に絶縁されており、浮遊電位である。そして、可動式基板保持機構４２上に基板４３ａ、４３ｂ、４３ｃ、例えば半導体ウェハが載置される。そして、可動式基板保持機構４２は基板４３ａ、４３ｂ、４３ｃを所定の温度に維持するための加熱機構を内蔵するが図示していない。さらに、ターゲット４８と可動式基板保持機構４２および基板４３ａ、４３ｂ、４３ｃの間には可動式シャッタ４７が載置され、電気的に接地されている。
【０００５】
そして、下部電極４５と真空容器４１（接地）間に高周波電源４６により、所定の高周波電力が所定の負のＤＣバイアスのもとに与えられる。
【０００６】
このスパッタリング装置で成膜処理を行うには、まず、可動式基板保持機構４２上に基板４３ａ、４３ｂ、４３ｃ（例えばウェハ）を載置し、図示しない排気口につながる真空ポンプ（図示せず）により真空に引き、次に、図示しないガス導入口から所定のガス（例えばＡｒガス）を所定流量導入しつつ排気口（図示せず）と真空ポンプ（図示せず）との間に介在する可変コンダクタンスバルブ（図示せず）を調節して所定の圧力に調節する。そして、高周波電力を印加してプラズマを発生させターゲット４８をスパッタする。その際、ターゲット４８最表面は不純物が付着しているため、スパッタリングを開始した直後のスパッタ粒子を基板４３ａ、４３ｂ、４３ｃに付着させないために可動式シャッタ４７を基板４３ａ、４３ｂ、４３ｃとターゲット４８の間に挿入しておく（プリスパッタ）。しばらくスパッタリングを続け、ターゲット４８表面がスパッタされ、新鮮な面が露出したところで、可動式シャッタ４７をターゲットと基板４３ａ、４３ｂ、４３ｃの間から退避させ、被処理基板４３ａへ薄膜を形成する。
【０００７】
そこで、ターゲット４８から飛散する成分は被処理基板４３ａ上に積もって成膜される。そして、ターゲット４８から飛散する成分は基板４３ａに向かうものばかりではなく、他の方向に向かうものもある。それが真空容器４１の内壁やその他の図示しないスパッタ室内の構造物に付着するとその清掃が困難なので下部電極４５と可動式基板保持機構４２を取り囲むように防着板４４を配置する。防着板４４は金属でなり、真空容器４１に電気的につながり接地電位となっていて、着脱容易として表面に付着したスパッタ物質が厚くなるととりはずして清掃するようにしている。そして、防着板４４は基板４３ａ、４３ｂ、４３ｃの出し入れのために部分的に待避可能となっているが図示を省略している。
【０００８】
また、特許文献１には、イオンプレーティング装置においてプラズマ密度の高均一化および高密度プラズマ形成のために可動式シャッタを浮遊電位にすることも開示されており、さらに、特許文献２には、ＥＣＲプラズマＣＶＤ装置においてパーティクル低減のために可動式シャッタを浮遊電位とすることが開示されている。
【０００９】
【特許文献１】
特開平９−２５６１４８号公報
【特許文献２】
特開平７−５８０３３号公報
【００１０】
【発明が解決しようとする課題】
しかしながら、従来例のスパッタリングを行うプラズマ処理装置では、プリスパッタが終了し、可動式シャッタ退避時にプラズマが可動式シャッタ移動方向に引っ張られ、結果的にターゲット直上にある被処理基板以外の基板もプラズマにさらされてしまい、不良となるという問題点があった。
【００１１】
本発明は、上記従来の問題点に鑑み、プリスパッタが終了し可動式シャッタが退避しても被処理基板以外の基板がプラズマにさらされることなく、安定してスパッタリングが行えるプラズマ処理装置および方法を提供するものである。
【００１２】
【課題を解決するための手段】
本願第１の発明のプラズマ処理装置は、プラズマ処理室を形成する容器内に、少なくとも２枚以上の基板保持できる可動式の基板保持部と、前記基板に形成する薄膜の材料で構成されたターゲットと、前記基板と前記ターゲットとの間の可動式シャッタ機構と、少なくとも一部の端部において向かい合う面間の距離がシース厚み以上である二重金属板で構成された防着板とを具備し、前記可動式シャッタが浮遊電位であることを特徴とする。
【００１３】
本願第２の発明のプラズマ処理装置は、プラズマ処理室を形成する容器内に、少なくとも２枚以上の基板保持できる可動式の基板保持部と、前記基板に形成する薄膜の材料で構成されたターゲットと、前記基板と前記ターゲットとの間の可動式シャッタ機構と、少なくとも一部の端部において向かい合う面間の距離がシース厚み以上である二重金属板で構成された防着板とを具備し、前記可動式基板保持機構と前記基板は浮遊電位であり、かつ、前記可動式シャッタが浮遊電位かつ前記基板保持機構と前記基板と同電位であり、かつ、少なくとも可動時は接地電位となる電位切り替え機構を有することを特徴とする。
【００１４】
本願第３の発明のプラズマ処理装置は、プラズマ処理室を形成する容器内に、少なくとも２枚以上の基板保持できる可動式の基板保持部と、前記基板に形成する薄膜の材料で構成されたターゲットと、前記基板と前記ターゲットとの間の可動式シャッタ機構と、少なくとも一部の端部において向かい合う面間の距離がシース厚み以上である二重金属板で構成された防着板とを具備し、前記可動式シャッタが接地電位であり、少なくとも可動時は浮遊電位となる電位切り替え機構を有することを特徴とする。
【００１５】
本願第１から３の発明のプラズマ処理装置において、好適には前記薄膜が誘電体であることが望ましい。更に好適には前記基板が少なくとも３００℃以上に加熱できる基板加熱機構を有することが望ましい。さらに好適には前記可動式シャッタを前記基板と前記ターゲットの間に挿入した際、前記ターゲットと前記可動式シャッタ間の距離が５０ｍｍ以下であることが望ましい。さらに好適には前記可動式シャッタを前記基板と前記ターゲットの間に挿入した際、前記ターゲットと前記可動式シャッタ間の距離が３０ｍｍ以下であることが望ましい。
【００１６】
本願第４の発明のプラズマ処理方法は、基板をターゲットの対向面に載置する工程と、前記ターゲットと前記基板との間に挿入された浮遊電位の前記可動式シャッタと浮遊電位の前記可動式基板保持機構とを電気的に接続し導電位とする工程と、前記ターゲットと前記可動式シャッタの間にプラズマを発生させる工程と、前記可動式シャッタを前記ターゲットと前記基板との間から退避させることで前記基板に前記ターゲット材料を成分とする薄膜を形成する工程とを含むことを特徴とする。
【００１７】
本願第５の発明のプラズマ処理方法は、基板をターゲットの対向面に載置する工程と、前記ターゲットと前記基板との間に挿入された接地電位の前記可動式シャッタと、前記ターゲットの間にプラズマを発生させる工程と、前記可動式シャッタを浮遊電位に切り替える工程と、浮遊電位となった前記可動式シャッタを前記ターゲットと前記基板との間から退避させることで前記基板に前記ターゲット材料を成分とする薄膜を形成する工程とを含むことを特徴とする。
【００１８】
【発明の実施の形態】
（実施の形態１）
図１は本発明の第１の実施の形態を示す図である。これは真空容器４１内に複数の基板４３ａ、４３ｂ、４３ｃ（例えば、Ｓｉ基板）を投入し連続的にスパッタリングにより誘電体であるＳｉＯ_２薄膜を形成するプラズマ処理装置の例である。
【００１９】
図１において真空容器４１の下部にターゲット４８（ターゲットとしては、所望の絶縁膜を構成する元素でできたもの、もしくは反応性ガスと反応して所望の絶縁物を形成することができる材料が好ましいが、今回はＳｉＯ_２を用いた）および下部電極４５を配し、真空容器４１の上部に基板４３ａ、４３ｂ、４３ｃを複数枚配置可能な可動式基板保持機構４２、ターゲット４８直上の基板４３ａに成膜を行い、終わると可動式基板保持機構４２が移動し次の基板４３ｂに成膜を行う。
【００２０】
また、ターゲット４８を囲むようにＳＵＳ性で筒状の二重防着板１１ａ、１１ｂが設けられており、内側防着板１１ａおよび、外側防着板１１ｂは接地電位である。上部に行くに従って二枚の防着板１１ａ、１１ｂ間の距離が離れて行き、最上部ではシース厚み以上の間隔（今回は１０ｍｍとした）となっている。
【００２１】
また、ターゲット４８と基板４３ａの間に可動式シャッタ４７が挿入できるように二重防着板１１ａ、１１ｂは上下に二分割されている。この真空容器４１中にＡｒとＯ_２の混合ガスを導入した。導入するガスとしては不活性ガス（不活性ガスにはＨｅ，Ｎｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｒｎ等がある）のみ、あるいは、不活性ガスと反応性ガス（反応性ガスにはＯ_２、Ｎ_２、等があるが成膜したい物質が酸化物ならＯ_２、窒化物ならＮ_２が好ましい）、あるいは反応性ガスのみを導入する。可動式シャッタ４７はセラミック等の絶縁物１２を介して真空容器４１と接続されており浮遊電位である。この可動式シャッタ４７をターゲット４８と基板４３ａ、４３ｂ、４３ｃの間に挿入した状態で、下部電極４３−真空容器４１間に１ｋＷ高周波電力を印加した（ターゲット４７が導電性のものであれば直流電力でもよい）。
【００２２】
すると、ターゲット４７直上にプラズマが発生し、プリスパッタが開始され、ターゲット４７からスパッタされたＳｉＯ_２は可動式シャッタ４７に付着し、基板４３ａ、４３ｂ、４３ｃに付着することはない。ターゲット４８最表面がスパッタされ新鮮な面が露出したころに可動式シャッタ４７を退避させ、基板４３ａへのＳｉＯ_２薄膜の形成を開始した。その際、可動式シャッタ４７は浮遊電位であるためプラズマが引っ張られることはなかった。
【００２３】
以上のことにより、プラズマが二重防着板１１ａ、１１ｂの外側に広がることがなく、被処理基板４３ａ以外の基板４３ｂ、４３ｃにプラズマがあたることなく安定してプラズマ処理を行うことができた。
【００２４】
なお、本実施の形態１で示した例は基板加熱機構を有していないが、３００℃以上に基板加熱が可能な基板加熱機構を有していても良い。また、可動式シャッタ４７とターゲット４８間の距離は明示していないが５０ｍｍ以下であることが望ましく、更に望ましくは３０ｍｍ以下である。
【００２５】
（実施の形態２）
図２は本発明の第２の実施の形態を示す図である。これは真空容器４１内に複数の基板４３ａ、４３ｂ、４３ｃ（例えばＳｉ基板）を投入し連続的にスパッタリングにより誘電体であるＳＴＯ（ＳｒＴｉＯ_３）薄膜を形成するプラズマ処理装置の例である。第１の実施の形態との相違点は、可動式シャッタ４７の電位を接地電位と浮遊電位に切り替える電位切り替えスイッチ２２を具備している点である。また、基板加熱機構２１を有しておりＳｉ基板４３ａ、４３ｂ、４３ｃを３００℃以上に加熱することができる点である。基板４３ａ、４３ｂ、４３ｃが加熱されるために可動式シャッタ４７が基板４３ａ、４３ｂ、４３ｃに近いと基板４３ａ、４３ｂ、４３ｃの温度が変化してしまうために、可動式シャッタ４７とターゲット４８間の距離は約３０ｍｍと近く配置し、基板４３ａ、４３ｂ、４３ｃからは遠ざけている点である。
【００２６】
まず、基板加熱機構２１により基板４３ａ、４３ｂ、４３ｃを３５０℃に加熱した。次に、この真空容器４１中にＡｒとＯ_２の混合ガスを導入した。導入するガスとしては不活性ガス（不活性ガスにはＨｅ，Ｎｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｒｎ等がある）のみ、あるいは、不活性ガスと反応性ガス（反応性ガスにはＯ_２、Ｎ_２、等があるが成膜したい物質が酸化物ならＯ_２、窒化物ならＮ_２が好ましい）、あるいは反応性ガスのみを導入する。
【００２７】
可動式シャッタ４７は、基板４３ａ、４３ｂ、４３ｃとターゲット４８の間に挿入しておき電位は接地電位にしておく。そして、下部電極４５と真空容器４１間に１ｋＷ高周波電力を印加した（ターゲット４８が導電性のものであれば直流電力でもよい）。すると、ターゲット４８直上にプラズマが発生し、プリスパッタが開始され、ターゲット４８からスパッタされたＳＴＯは可動式シャッタ４７に付着し、基板４３ａ、４３ｂ、４３ｃに付着することはない。
【００２８】
また、可動式シャッタ４７は接地電位であるので、可動式シャッタ４７とターゲット４８の間が３０ｍｍと近いにもかかわらず安定してプラズマを発生することができた。ターゲット４８最表面がスパッタされ新鮮な面が露出したころに、電位切り替えスイッチ２２で可動式シャッタ４７を浮遊電位にした後に可動式シャッタ４７を退避させ、基板４３ａへのＳＴＯ薄膜の形成を開始した。その際、可動式シャッタ４７は浮遊電位であるためプラズマが引っ張られることはなかった。
【００２９】
以上のことにより、プリスパッタ時に安定してプラズマを発生させることができ、かつプラズマが二重防着板１１ａ、１１ｂの外側に広がることがなく、被処理基板４３ａ以外の基板４３ｂ、４３ｃにプラズマがあたることなく安定してプラズマ処理を行うことができた。
【００３０】
なお、この実施の形態２で示した例は可動式シャッタ４７とターゲット４８間の距離は３０ｍｍであるが基板４３ａ、４３ｂ、４３ｃとターゲット４８の距離が十分はなれていれば５０ｍｍ以下であっても良い。
【００３１】
（実施の形態３）
図３は本発明の第３の実施の形態を示す図である。これは真空容器４１内に複数の基板４３ａ、４３ｂ、４３ｃを投入し連続的にスパッタリングによりＳｉＯ_２薄膜を形成するプラズマ処理装置の例である。第１の実施の形態との相違点は浮遊電位である可動式シャッタ４７と浮遊電位である可動式基板保持機構４２を電気的に接続する、接続機構３１を具備している点である。
【００３２】
この真空容器４１中にＡｒとＯ_２の混合ガスを導入した。導入するガスとしては不活性ガス（不活性ガスにはＨｅ，Ｎｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｒｎ等がある）のみ、あるいは、不活性ガスと反応性ガス（反応性ガスにはＯ_２、Ｎ_２、等があるが成膜したい物質が酸化物ならＯ_２、窒化物ならＮ_２が好ましい）、あるいは反応性ガスのみを導入する。浮遊電位の可動式シャッタ４７は基板４３ａ、４３ｂ、４３ｃとターゲット４８の間に挿入しておき、接続機構３１により浮遊電位の可動式基板保持機構４２と浮遊電位の可動式シャッタ４７を電気的に接続しておく。そして下部電極４５と真空容器４１間に１ｋＷ高周波電力を印加した（ターゲット４８が導電性のものであれば直流電力でもよい）。すると、ターゲット４８直上にプラズマが発生し、プリスパッタが開始され、ターゲット４８からスパッタされたＳｉＯ_２は可動式シャッタ４７に付着し、基板４３ａ、４３ｂ、４３ｃに付着することはない。このとき、可動式シャッタ４７と可動式基板保持機構４２は同電位であるために、可動式シャッタ４７と可動式基板保持機構４２との間で異常放電が起こることなく、安定してプラズマを発生することができた。ターゲット４８最表面がスパッタされ新鮮な面が露出したところに、可動式シャッタ４７を退避させ、基板４３ａへのＳｉＯ_２膜の形成を開始した。その際、可動式シャッタ４７は浮遊電位であるためプラズマが引っ張られることはなかった。
【００３３】
以上のことにより、プリスパッタ時に異常放電がおこり被処理基板４３ａを不良にすることなく安定してプラズマを発生させることができ、かつ、プラズマが二重防着板１１ａ、１１ｂの外側に広がることがなく、被処理基板４３ａ以外の基板４３ｂ、４３ｃにプラズマが当たることがなく安定してプラズマ処理を行うことができた。
【００３４】
なお、この実施の形態３で示した例は基板加熱機構を有していないが、３００℃以上に基板加熱が可能な基板加熱機構を有していても良い。また可動式シャッタ４７とターゲット４８間の距離は明示していないが５０ｍｍ以下であることが望ましく、更に望ましくは、３０ｍｍ以下である。
【００３５】
【発明の効果】
以上の説明から明らかなように、本願第１発明のプラズマ処理装置によれば、プラズマ処理室を形成する容器内に、少なくとも２枚以上の基板保持できる可動式の基板保持部と、前記基板に形成する薄膜の材料で構成されたターゲットと、前記基板と前記ターゲットとの間の可動式シャッタ機構と、少なくとも一部の端部において向かい合う面間の距離がシース厚み以上である二重金属板で構成された防着板とを具備し、前記可動式シャッタが浮遊電位であるために、プリスパッタが終了し可動式シャッタが退避しても被処理基板以外の基板がプラズマにさらされることなく、安定してスパッタリングが行える。
【００３６】
また、本願第２発明のプラズマ処理装置によれば、プラズマ処理室を形成する容器内に、少なくとも２枚以上の基板保持できる可動式の基板保持部と、前記基板に形成する薄膜の材料で構成されたターゲットと、前記基板と、前記ターゲットとの間の可動式シャッタ機構と、少なくとも一部の端部において向かい合う面間の距離がシース厚み以上である二重金属板で構成された防着板とを具備し、前記可動式基板保持機構と前記基板は浮遊電位であり、かつ、前記可動式シャッタが浮遊電位かつ前記基板保持機構と前記基板と同電位であり、かつ、少なくとも可動時は接地電位となる電位切り替え機構を有するため、プリスパッタが終了し可動式シャッタが退避しても被処理基板以外の基板がプラズマにさらされることなく、安定してスパッタリングが行え、かつプリスパッタ時に安定してプラズマを発生させることができるプラズマ処理装置を提供するものである。
【００３７】
また、本願第３発明のプラズマ処理装置によれば、プラズマ処理室を形成する容器内に、少なくとも２枚以上の基板保持できる可動式の基板保持部と、前記基板に形成する薄膜の材料で構成されたターゲットと、前記基板と前記ターゲットとの間の可動式シャッタ機構と、少なくとも一部の端部において向かい合う面間の距離がシース厚み以上である二重金属板で構成された防着板とを具備し、前記可動式シャッタが接地電位であり、少なくとも可動時は浮遊電位となる電位切り替え機構を有するため、プリスパッタが終了し可動式シャッタが退避しても被処理基板以外の基板がプラズマにさらされることなく、安定してスパッタリングが行え、かつプリスパッタ中に異常放電が起きることのないプラズマ処理装置を提供するものである。
【００３８】
また、本願第４発明のプラズマ処理方法によれば、基板をターゲットの対向面に載置する工程と、前記ターゲットと前記基板との間に挿入された浮遊電位の前記可動式シャッタと浮遊電位の前記可動式基板保持機構とを電気的に接続し導電位とする工程と、前記ターゲットと前記可動式シャッタの間にプラズマを発生させる工程と、前記可動式シャッタを前記ターゲットと前記基板との間から退避させることで前記基板に前記ターゲット材料を成分とする薄膜を形成する工程とを含むために、プリスパッタが終了し可動式シャッタが退避しても被処理基板以外の基板がプラズマにさらされることなく、安定してスパッタリングが行え、かつプリスパッタ時に安定してプラズマを発生させることができるプラズマ処理方法を提供するものである。
【００３９】
また、本願第５発明のプラズマ処理方法によれば、基板をターゲットの対向面に載置する工程と、前記ターゲットと前記基板との間に挿入された接地電位の前記可動式シャッタと、前記ターゲットの間にプラズマを発生させる工程と、前記可動式シャッタを浮遊電位に切り替える工程と、浮遊電位となった前記可動式シャッタを前記ターゲットと前記基板との間から退避させることで前記基板に前記ターゲット材料を成分とする薄膜を形成する工程とを含むために、プリスパッタが終了し可動式シャッタが退避しても被処理基板以外の基板がプラズマにさらされることなく、安定してスパッタリングが行え、かつプリスパッタ中に異常放電が起きることのないプラズマ処理方法を提供するものである。
【図面の簡単な説明】
【図１】本発明の第１の実施例で用いたプラズマ処理装置の構成を示した断面図
【図２】本発明の第２の実施例で用いたプラズマ処理装置の構成を示した断面図
【図３】本発明の第３の実施例で用いたプラズマ処理装置の構成を示した断面図
【図４】従来例で用いたプラズマ処理装置の構成を示した断面図
【符号の説明】
１１ａ、１１ｂ二重防着板
１２絶縁物
２１基板加熱機構
２２電位切り替え機構
３１接続機構
４１真空容器
４２可動式基板保持機構
４３ａ基板（被処理）
４３ｂ、４３ｃ基板（被処理以外）
４４防着板
４５下部電極
４６高周波電源
４７可動式シャッタ
４８ターゲット[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma processing method and apparatus for forming a thin film by sputtering.
[0002]
[Prior art]
In a manufacturing process of a semiconductor integrated circuit (hereinafter, referred to as an “IC”), various dielectric films are formed. The purpose is, for example, an interlayer insulating film, a mask for etching, selective ion implantation, or selective electrode formation, passivation, a dielectric film of a capacitor, and the like. The material and the plasma processing method are selected depending on the purpose. For example, various methods such as CVD, dry etching, and sputtering are used. In recent years, to reduce the size of ICs, it has been studied to perform a plasma treatment on a dielectric film of a capacitor with a high dielectric substance such as barium strontium titanate (BST) or strontium titanate (STO). Further, plasma treatment of ferroelectric substances such as lead zirconate titanate (PZT) and strontium bismuth tantalate (SBT) for sensors, actuators, and non-volatile memory devices has been studied.
[0003]
A conventional plasma processing apparatus for performing sputtering will be described with reference to the drawings. FIG. 5 is a longitudinal sectional view conceptually showing a sputtering apparatus capable of continuously processing a plurality of substrates. In the conventional sputtering apparatus, a sputtering chamber is formed by a vacuum chamber 41 which can be evacuated, and a target 48 is fixed and held by a lower electrode 45 below the sputtering chamber. The lower electrode 45 is electrically insulated from the container 41. The lower electrode 45 incorporates a water cooling mechanism to prevent the temperature of the target 48 from rising, but is not shown.
[0004]
A movable substrate holding mechanism 42 is arranged above and in parallel with the lower electrode 45 above the sputtering chamber. The movable substrate holding mechanism 42 is electrically insulated from the vacuum container 41 and has a floating potential. Then, the substrates 43a, 43b, 43c, for example, a semiconductor wafer are mounted on the movable substrate holding mechanism. The movable substrate holding mechanism 42 incorporates a heating mechanism for maintaining the substrates 43a, 43b, 43c at a predetermined temperature, but is not shown. Further, a movable shutter 47 is placed between the target 48, the movable substrate holding mechanism 42 and the substrates 43a, 43b, 43c, and is electrically grounded.
[0005]
Then, a predetermined high-frequency power is applied between the lower electrode 45 and the vacuum vessel 41 (ground) by a high-frequency power supply 46 under a predetermined negative DC bias.
[0006]
In order to perform a film forming process using this sputtering apparatus, first, the substrates 43a, 43b, and 43c (for example, wafers) are placed on the movable substrate holding mechanism 42, and a vacuum pump (not shown) connected to an exhaust port (not shown) Then, a predetermined gas (for example, Ar gas) is introduced at a predetermined flow rate from a gas inlet (not shown) while a variable gas interposed between an exhaust port (not shown) and a vacuum pump (not shown). A predetermined pressure is adjusted by adjusting a conductance valve (not shown). Then, high frequency power is applied to generate plasma, and the target 48 is sputtered. At this time, since impurities are attached to the outermost surface of the target 48, the movable shutter 47 is attached to the substrates 43a, 43b, 43c and the target 48 so that sputter particles immediately after the start of sputtering are not attached to the substrates 43a, 43b, 43c. (Pre-sputtering). Sputtering is continued for a while, and when the surface of the target 48 is sputtered and a fresh surface is exposed, the movable shutter 47 is retracted from between the target and the substrates 43a, 43b, 43c to form a thin film on the substrate 43a to be processed.
[0007]
Therefore, the components scattered from the target 48 are deposited and formed on the substrate 43a to be processed. The components scattered from the target 48 are not only directed toward the substrate 43a but also directed toward other directions. If it adheres to the inner wall of the vacuum chamber 41 or other structures in the sputter chamber (not shown), it is difficult to clean the sputter chamber. Therefore, the deposition prevention plate 44 is arranged so as to surround the lower electrode 45 and the movable substrate holding mechanism 42. The deposition-preventing plate 44 is made of metal, is electrically connected to the vacuum vessel 41 and has a ground potential, and is easily detachable so that when the sputtered substance attached to the surface becomes thick, it is removed and cleaned. The attachment-preventing plate 44 is partially evacuable for taking in and out the substrates 43a, 43b, and 43c, but is not shown.
[0008]
Further, Patent Document 1 discloses that a movable shutter is set to a floating potential in order to achieve high uniformity of plasma density and formation of high-density plasma in an ion plating apparatus. It is disclosed that a movable shutter is set to a floating potential for particle reduction in an ECR plasma CVD apparatus.
[0009]
[Patent Document 1]
JP-A-9-256148 [Patent Document 2]
JP-A-7-58033
[Problems to be solved by the invention]
However, in the conventional plasma processing apparatus that performs sputtering, the pre-sputtering is completed, and when the movable shutter is retracted, the plasma is pulled in the movable shutter moving direction. As a result, the substrate other than the target substrate just above the target is also subjected to the plasma. , And there is a problem that it becomes defective.
[0011]
In view of the above conventional problems, the present invention provides a plasma processing apparatus and method capable of performing stable sputtering without exposing substrates other than the substrate to be processed even if pre-sputtering is completed and the movable shutter is retracted. Is provided.
[0012]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a plasma processing apparatus comprising: a movable substrate holding section capable of holding at least two or more substrates in a container forming a plasma processing chamber; and a target formed of a thin film material formed on the substrate. And, comprising a movable shutter mechanism between the substrate and the target, a deposition plate made of a double metal plate wherein the distance between facing surfaces at least at some ends is equal to or greater than the sheath thickness, The movable shutter has a floating potential.
[0013]
According to a second aspect of the present invention, there is provided a plasma processing apparatus comprising: a movable substrate holding portion capable of holding at least two or more substrates in a container forming a plasma processing chamber; and a target formed of a thin film material formed on the substrate. And, comprising a movable shutter mechanism between the substrate and the target, a deposition plate made of a double metal plate wherein the distance between facing surfaces at least at some ends is equal to or greater than the sheath thickness, The movable substrate holding mechanism and the substrate have a floating potential, and the movable shutter has a floating potential and the same potential as the substrate holding mechanism and the substrate, and a potential switch that is at least a ground potential when movable. It has a mechanism.
[0014]
According to a third aspect of the present invention, there is provided a plasma processing apparatus comprising: a movable substrate holding portion capable of holding at least two or more substrates in a container forming a plasma processing chamber; and a target formed of a thin film material formed on the substrate. And, comprising a movable shutter mechanism between the substrate and the target, a deposition plate made of a double metal plate wherein the distance between facing surfaces at least at some ends is equal to or greater than the sheath thickness, The movable shutter has a potential switching mechanism that is at a ground potential and becomes a floating potential at least when the shutter is movable.
[0015]
In the plasma processing apparatus according to the first to third aspects of the present invention, it is preferable that the thin film is a dielectric. More preferably, it is desirable to have a substrate heating mechanism capable of heating the substrate to at least 300 ° C. or higher. More preferably, when the movable shutter is inserted between the substrate and the target, the distance between the target and the movable shutter is desirably 50 mm or less. More preferably, when the movable shutter is inserted between the substrate and the target, the distance between the target and the movable shutter is desirably 30 mm or less.
[0016]
The plasma processing method according to a fourth aspect of the present invention includes a step of mounting a substrate on a facing surface of a target, the movable shutter having a floating potential inserted between the target and the substrate, and the movable shutter having a floating potential inserted between the target and the substrate. Electrically connecting the substrate holding mechanism to a conductive state, generating plasma between the target and the movable shutter, and retracting the movable shutter from between the target and the substrate. Forming a thin film containing the target material as a component on the substrate.
[0017]
A plasma processing method according to a fifth aspect of the present invention includes a step of placing a substrate on a facing surface of a target, the movable shutter having a ground potential inserted between the target and the substrate, and A step of generating plasma; a step of switching the movable shutter to a floating potential; and a step of retracting the movable shutter at the floating potential from between the target and the substrate, thereby forming the target material on the substrate. And forming a thin film.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
FIG. 1 is a diagram showing a first embodiment of the present invention. This is an example of a plasma processing apparatus in which a plurality of substrates 43a, 43b, 43c (for example, a Si substrate) are put in a vacuum vessel 41 and a dielectric SiO ₂ thin film is continuously formed by sputtering.
[0019]
In FIG. 1, a target 48 (a target made of an element constituting a desired insulating film or a material capable of reacting with a reactive gas to form a desired insulator is preferable as a target in a lower portion of the vacuum vessel 41). However, this time, SiO ₂ is used) and a lower electrode 45 is arranged, and a movable substrate holding mechanism 42 in which a plurality of substrates 43 a, 43 b, and 43 c can be arranged above the vacuum vessel 41, and a substrate 43 a just above the target 48. After the film formation, the movable substrate holding mechanism 42 moves to perform the film formation on the next substrate 43b.
[0020]
In addition, SUS tubular double deposition prevention plates 11a and 11b are provided so as to surround the target 48, and the inside deposition prevention plate 11a and the outside deposition prevention plate 11b are at the ground potential. The distance between the two deposition-preventing plates 11a and 11b increases as going toward the upper part, and at the uppermost part, the distance is equal to or greater than the sheath thickness (this time is 10 mm).
[0021]
In addition, the double shield plates 11a and 11b are vertically divided into two so that the movable shutter 47 can be inserted between the target 48 and the substrate 43a. A mixed gas of Ar and O ₂ was introduced into the vacuum vessel 41. As the gas to be introduced, only an inert gas (an inert gas includes He, Ne, Ar, Kr, Xe, Rn, etc.), or an inert gas and a reactive gas (O ₂ , N _2, there are an equal O ₂ if material to be deposited _oxide, N ₂ if nitrides are preferred), or introducing only reactive gas. The movable shutter 47 is connected to the vacuum container 41 via an insulator 12 such as a ceramic, and has a floating potential. With this movable shutter 47 inserted between the target 48 and the substrates 43a, 43b, 43c, a 1 kW high-frequency power was applied between the lower electrode 43 and the vacuum vessel 41 (if the target 47 was conductive, DC power was applied. It may be electric power).
[0022]
Then, plasma is generated immediately above the target 47, and pre-sputtering is started, and SiO ₂ sputtered from the target 47 adheres to the movable shutter 47 and does not adhere to the substrates 43a, 43b, 43c. When the outermost surface of the target 48 was sputtered and the fresh surface was exposed, the movable shutter 47 was retracted, and the formation of the SiO ₂ thin film on the substrate 43a was started. At that time, since the movable shutter 47 was at the floating potential, the plasma was not pulled.
[0023]
As described above, the plasma did not spread outside the double deposition-preventing plates 11a and 11b, and the plasma processing could be performed stably without being exposed to the plasma on the substrates 43b and 43c other than the substrate 43a to be processed. .
[0024]
Note that the example shown in Embodiment 1 does not have a substrate heating mechanism, but may have a substrate heating mechanism capable of heating a substrate to 300 ° C. or higher. The distance between the movable shutter 47 and the target 48 is not explicitly shown, but is preferably 50 mm or less, and more preferably 30 mm or less.
[0025]
(Embodiment 2)
FIG. 2 is a diagram showing a second embodiment of the present invention. This is an example of a plasma processing apparatus in which a plurality of substrates 43a, 43b, 43c (for example, a Si substrate) are put in a vacuum vessel 41 and a STO (SrTiO ₃ ) thin film as a dielectric is continuously formed by sputtering. The difference from the first embodiment is that a potential switch 22 for switching the potential of the movable shutter 47 between the ground potential and the floating potential is provided. Further, it has the substrate heating mechanism 21 and can heat the Si substrates 43a, 43b and 43c to 300 ° C. or more. If the movable shutter 47 is close to the substrates 43a, 43b, and 43c because the substrates 43a, 43b, and 43c are heated, the temperature of the substrates 43a, 43b, and 43c changes. Is a distance of about 30 mm and is far from the substrates 43a, 43b and 43c.
[0026]
First, the substrates 43a, 43b, and 43c were heated to 350 ° C. by the substrate heating mechanism 21. Next, a mixed gas of Ar and O ₂ was introduced into the vacuum vessel 41. As the gas to be introduced, only an inert gas (an inert gas includes He, Ne, Ar, Kr, Xe, Rn, etc.), or an inert gas and a reactive gas (O ₂ , N _2, there are an equal O ₂ if material to be deposited _oxide, N ₂ if nitrides are preferred), or introducing only reactive gas.
[0027]
The movable shutter 47 is inserted between the substrates 43a, 43b, 43c and the target 48, and the potential is set to the ground potential. Then, a 1 kW high-frequency power was applied between the lower electrode 45 and the vacuum vessel 41 (DC power may be used if the target 48 is conductive). Then, plasma is generated immediately above the target 48, pre-sputtering is started, and the STO sputtered from the target 48 adheres to the movable shutter 47 and does not adhere to the substrates 43a, 43b, 43c.
[0028]
Further, since the movable shutter 47 was at the ground potential, plasma could be stably generated even though the distance between the movable shutter 47 and the target 48 was close to 30 mm. At the time when the outermost surface of the target 48 was sputtered and the fresh surface was exposed, the movable shutter 47 was set to the floating potential by the potential changeover switch 22, and then the movable shutter 47 was retracted to start forming the STO thin film on the substrate 43a. . At that time, since the movable shutter 47 was at the floating potential, the plasma was not pulled.
[0029]
As described above, the plasma can be stably generated during the pre-sputtering, and the plasma does not spread outside the double deposition-preventing plates 11a, 11b, and the plasma is applied to the substrates 43b, 43c other than the substrate 43a to be processed. Plasma treatment could be performed stably without hitting.
[0030]
In the example shown in the second embodiment, the distance between the movable shutter 47 and the target 48 is 30 mm. However, if the distance between the substrates 43a, 43b, 43c and the target 48 is sufficiently large, even if the distance is 50 mm or less. good.
[0031]
(Embodiment 3)
FIG. 3 is a diagram showing a third embodiment of the present invention. This is an example of a plasma processing apparatus in which a plurality of substrates 43a, 43b, and 43c are charged into a vacuum vessel 41 and a SiO ₂ thin film is continuously formed by sputtering. The difference from the first embodiment is that a connection mechanism 31 for electrically connecting a movable shutter 47 having a floating potential and a movable substrate holding mechanism 42 having a floating potential is provided.
[0032]
A mixed gas of Ar and O ₂ was introduced into the vacuum vessel 41. As the gas to be introduced, only an inert gas (an inert gas includes He, Ne, Ar, Kr, Xe, Rn, etc.), or an inert gas and a reactive gas (O ₂ , N _2, there are an equal O ₂ if material to be deposited _oxide, N ₂ if nitrides are preferred), or introducing only reactive gas. The floating potential movable shutter 47 is inserted between the substrates 43a, 43b, 43c and the target 48, and the floating potential movable substrate holding mechanism 42 and the floating potential movable shutter 47 are electrically connected by the connection mechanism 31. Connect. Then, 1 kW high frequency power was applied between the lower electrode 45 and the vacuum vessel 41 (DC power may be used if the target 48 is conductive). Then, plasma is generated immediately above the target 48, pre-sputtering is started, and SiO ₂ sputtered from the target 48 adheres to the movable shutter 47, and does not adhere to the substrates 43a, 43b, 43c. At this time, since the movable shutter 47 and the movable substrate holding mechanism 42 have the same potential, the plasma is generated stably without abnormal discharge occurring between the movable shutter 47 and the movable substrate holding mechanism 42. We were able to. When the outermost surface of the target 48 was sputtered and the fresh surface was exposed, the movable shutter 47 was retracted, and the formation of the SiO ₂ film on the substrate 43a was started. At that time, since the movable shutter 47 was at the floating potential, the plasma was not pulled.
[0033]
As described above, abnormal discharge occurs during pre-sputtering, plasma can be generated stably without causing the substrate to be processed 43a to be defective, and the plasma spreads outside the double deposition prevention plates 11a and 11b. Therefore, the plasma processing could be performed stably without the plasma being applied to the substrates 43b and 43c other than the substrate 43a to be processed.
[0034]
Note that the example shown in Embodiment 3 does not have a substrate heating mechanism, but may have a substrate heating mechanism capable of heating a substrate to 300 ° C. or higher. The distance between the movable shutter 47 and the target 48 is not explicitly shown, but is preferably 50 mm or less, and more preferably 30 mm or less.
[0035]
【The invention's effect】
As is clear from the above description, according to the plasma processing apparatus of the first invention of the present application, a movable substrate holding portion capable of holding at least two or more substrates in a container forming a plasma processing chamber; A target formed of a thin film material to be formed, a movable shutter mechanism between the substrate and the target, and a double metal plate in which a distance between facing surfaces at least at some ends is equal to or greater than a sheath thickness. The movable shutter is at a floating potential, so that even if pre-sputtering is completed and the movable shutter is retracted, substrates other than the substrate to be processed are not exposed to plasma and stable. To perform sputtering.
[0036]
Further, according to the plasma processing apparatus of the second invention of the present application, a movable substrate holding portion capable of holding at least two or more substrates in a container forming a plasma processing chamber, and a material of a thin film formed on the substrate Targeted, the substrate, a movable shutter mechanism between the target, and a deposition plate made of a double metal plate in which the distance between facing surfaces at least at some ends is equal to or greater than the sheath thickness. Wherein the movable substrate holding mechanism and the substrate have a floating potential, and the movable shutter has a floating potential and the same potential as the substrate holding mechanism and the substrate, and is at least a ground potential when movable. Even if pre-sputtering ends and the movable shutter retracts, substrates other than the substrate to be processed are not exposed to plasma, and the Ring can, and is intended to provide a plasma processing apparatus capable of generating a stable plasma at pre-sputtering.
[0037]
Further, according to the plasma processing apparatus of the third aspect of the present invention, a movable substrate holding portion capable of holding at least two or more substrates in a container forming a plasma processing chamber, and a material of a thin film formed on the substrate The target, the movable shutter mechanism between the substrate and the target, and a deposition plate made of a double metal plate in which the distance between facing surfaces at least at some ends is equal to or greater than the sheath thickness. Since the movable shutter has a ground potential, and has a potential switching mechanism that becomes a floating potential at least when the movable shutter is movable, even if pre-sputtering ends and the movable shutter retracts, substrates other than the substrate to be processed are exposed to plasma. An object of the present invention is to provide a plasma processing apparatus capable of performing stable sputtering without exposure, and preventing abnormal discharge during pre-sputtering.
[0038]
Further, according to the plasma processing method of the fourth invention of the present application, the step of mounting the substrate on the opposing surface of the target, the movable shutter having a floating potential inserted between the target and the substrate, and the floating shutter having a floating potential Electrically connecting the movable substrate holding mechanism to a conductive state, generating plasma between the target and the movable shutter, and moving the movable shutter between the target and the substrate. Forming a thin film containing the target material as a component on the substrate by retreating from the substrate, even if pre-sputtering ends and the movable shutter retreats, the substrate other than the substrate to be processed is exposed to plasma. It is intended to provide a plasma processing method capable of performing stable sputtering without generating plasma and generating plasma stably during pre-sputtering.
[0039]
According to the plasma processing method of the fifth invention of the present application, a step of mounting a substrate on a facing surface of a target; the movable shutter having a ground potential inserted between the target and the substrate; Generating a plasma during the process, switching the movable shutter to a floating potential, and retracting the movable shutter at the floating potential from between the target and the substrate, thereby forming the target on the substrate. And a step of forming a thin film containing a material as a component, even if pre-sputtering is completed and the movable shutter is retracted, substrates other than the substrate to be processed are not exposed to plasma, and sputtering can be performed stably. Another object of the present invention is to provide a plasma processing method in which abnormal discharge does not occur during pre-sputtering.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of a plasma processing apparatus used in a first embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a configuration of a plasma processing apparatus used in a second embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a configuration of a plasma processing apparatus used in a third embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a configuration of a plasma processing apparatus used in a conventional example.
11a, 11b Double deposition prevention plate 12 Insulator 21 Substrate heating mechanism 22 Potential switching mechanism 31 Connection mechanism 41 Vacuum container 42 Movable substrate holding mechanism 43a Substrate (processed)
43b, 43c Substrate (other than processing target)
44 Deposition plate 45 Lower electrode 46 High frequency power supply 47 Movable shutter 48 Target

Claims

A movable substrate holding unit capable of holding at least two or more substrates in a container forming a plasma processing chamber, a target formed of a thin film material formed on the substrate, and a target between the substrate and the target. A movable shutter mechanism, and a deposition plate made of a double metal plate having a distance between facing surfaces at least at some ends being equal to or greater than a sheath thickness, wherein the movable shutter has a floating potential. Characteristic plasma processing apparatus.

A movable substrate holding unit capable of holding at least two or more substrates in a container forming a plasma processing chamber, a target formed of a thin film material formed on the substrate, and a target between the substrate and the target. A movable shutter mechanism, and a deposition prevention plate formed of a double metal plate in which a distance between facing surfaces at least at some ends is equal to or greater than a sheath thickness, wherein the movable substrate holding mechanism and the substrate are floating. A plasma processing apparatus having a potential switching mechanism that is at a potential, the movable shutter is at a floating potential, at the same potential as the substrate holding mechanism and the substrate, and is at least a ground potential when it is movable. .

A movable substrate holding unit capable of holding at least two or more substrates in a container forming a plasma processing chamber, a target formed of a thin film material formed on the substrate, and a target between the substrate and the target. A movable shutter mechanism, comprising: a deposition prevention plate made of a double metal plate in which a distance between facing surfaces at least at some ends is equal to or greater than a sheath thickness, wherein the movable shutter is at a ground potential; A plasma processing apparatus having a potential switching mechanism that becomes a floating potential when movable.

The plasma processing apparatus according to claim 1, wherein the thin film is a dielectric.

The plasma processing apparatus according to claim 1, further comprising a substrate heating mechanism capable of heating the substrate to at least 300 ° C. or higher.

The distance according to claim 1, wherein when the movable shutter is inserted between the substrate and the target, a distance between the target and the movable shutter is 50 mm or less. 7. Plasma processing equipment.

6. The distance according to claim 1, wherein when the movable shutter is inserted between the substrate and the target, a distance between the target and the movable shutter is 30 mm or less. 7. Plasma processing equipment.

Electrically connecting the movable shutter of floating potential and the movable substrate holding mechanism of floating potential inserted between the target and the substrate; And a step of generating plasma between the target and the movable shutter; and retracting the movable shutter from between the target and the substrate to allow the substrate to contain the target material as a component. Forming a thin film to be formed.

Placing a substrate on a facing surface of a target, the movable shutter having a ground potential inserted between the target and the substrate, and generating plasma between the target; and the movable shutter. Switching the floating shutter to a floating potential; and retracting the movable shutter having the floating potential from between the target and the substrate to form a thin film containing the target material on the substrate. A plasma processing method characterized by the above-mentioned.