JP4408313B2

Movatterモバイル変換

Info

Publication number: JP4408313B2
Application number: JP30876599A
Authority: JP
Inventors: 英二廣瀬
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 1999-10-29
Filing date: 1999-10-29
Publication date: 2010-02-03
Anticipated expiration: 2019-10-29
Also published as: JP2001127045A

Description

Translated fromJapanese

【０００１】
【発明の属する技術分野】
本発明は，プラズマ処理装置およびプラズマ処理方法に関する。
【０００２】
【従来の技術】
従来，半導体装置の製造工程においては，各種プラズマ処理，例えばプラズマエッチング処理が行われている。プラズマエッチング処理は，プラズマエッチング装置を用いて行われる。該装置としては，処理室内に上部電極と下部電極とを対向配置した平行平板型装置が広く使用されている。かかる装置では，上部電極への第１高周波電力の印加により，処理室内に導入された処理ガスがプラズマ化される。さらに，下部電極に第１高周波電力よりも低い周波数の第２高周波電力を印加することにより，プラズマが被処理体に引き込まれる。このため，下部電極上に載置された被処理体，例えば半導体ウェハ（以下，「ウェハ」と称する。）に所定のエッチング処理が施される。
【０００３】
また，最近，半導体装置の超小型化および超高集積化傾向に伴い，エッチング処理においても超微細加工が要求されている。さらに，スループットの向上を図るために，処理の迅速化が求められている。このため，かかる技術的要求を達成するべく，プラズマエッチング装置の各種改良が試みられている。例えば，酸化膜（ＳｉＯ_２膜）用のエッチング装置では，プラズマ生成用の第１高周波電力の周波数を従来の１３．５６ＭＨｚ程度の周波数よりも高い周波数，例えば６０ＭＨｚに高めることにより，エッチングレートを向上させる技術が提案されている。ただし，かかる周波数の第１高周波電力を用いた場合には，プラズマの分布が不均一になり易くなる。そこで，さらに上記第２高周波電力をパワースプリッタにより電圧を分割し，分割された電力の一部を下部電極に印加し，一部を第１高周波電力に重畳する技術が提案されている。かかる重畳高周波電力によりプラズマを生成すると，プラズマの分布が均一化される。このため，高周波数の第１高周波電力を用いて処理を行っても，エッチングレートを向上させながら均一な処理を行うことが可能になる。さらに，ウェハの損傷も軽減される。このため，ウェハに超微細化処理を歩留り良く施すことが可能になる。
【０００４】
【発明が解決しようとする課題】
最近，生産性を向上させる観点から，大口径のウェハに処理を施すことが求められている。このため，エッチング処理においては，容積が大きい処理室内にプラズマを均一に生成し，かつ大型のウェハ全面にプラズマを均一に導入する必要がある。その結果，ウェハの大口径化に伴い，より大パワー（電力量）の高周波電力を上部電極および下部電極に印加することが求められる。しかしながら，上記パワースプリッタは，一種のトランスなので，第２高周波電力のパワーが大きくなると構成部材である線材やコア材が大型化する。また，パワースプリッタは，電力の供給効率向上の観点から一般的に下部電極近傍に設けられる。その結果，エッチング装置が大型化し，フットプリントの削減が困難であるという問題点がある。
【０００５】
また，コア材は，高周波電力のパワーや使用する周波数などに応じて製造されている。さらに，コア材は，適用される高周波電力のパワーが大きくなるほど特殊な構成になり，汎用性が低下する。このため，大パワー用のパワースプリッタを採用すると，装置の生産コストが増加するという問題点がある。
【０００６】
また，上記従来の技術では，パワースプリッタにより第２高周波電力を分割している。パワースプリッタでは，上部電極および下部電極に印加する電圧を所定の電圧比に設定することができる。しかし，処理時には，生成されたプラズマの作用により，上部電極から見たインピーダンスと下部電極から見たインピーダンスとの比が変化する。このため，パワースプリッタを用いた場合には，上記インピーダンス比の変化により，上部電極および下部電極に各々印加される分割された第２高周波電力のパワーが変化する。その結果，上記分割された第２高周波電力のパワーの制御が困難になり，より一層の処理の均一化を図ることができないという問題点がある。
【０００７】
本発明は，従来の技術が有する上記問題点に鑑みて成されたものである。そして，本発明の目的は，上記問題点およびその他の問題点を解決することが可能な，新規かつ改良されたプラズマ処理装置およびプラズマ処理方法を提供することである。
【０００８】
【課題を解決するための手段】
上記課題を解決するために，本発明の第１の観点によれば，請求項１に記載の発明のように，処理室内に対向配置された第１電極と第２電極との各々に高周波電力を印加して処理室内にプラズマを生成し，第２電極上に載置された被処理体にプラズマ処理を施すプラズマ処理装置において，第１電極に第１高周波電力を印加する第１高周波電源と，第２電極に第１高周波電力よりも低い周波数の第２高周波電力を印加する第２高周波電源と，第１高周波電力の周波数よりも低く第２高周波電力の周波数よりも高い周波数の第３高周波電力を出力し，第１高周波電力に第３高周波電力を重畳する第３高周波電源と，第２高周波電源と第３高周波電源に接続され，第２高周波電力の位相と第３高周波電力の位相との位相差を調整する位相制御手段と，を備えることを特徴とする，プラズマ処理装置が提供される。
【０００９】
かかる構成によれば，第１高周波電力に重畳する第３高周波電力を，第２高周波電源とは個別独立した第３高周波電源から出力する。かかる構成によれば，パワースプリッタを設けずに，重畳高周波電力を第１電極に印加できる。その結果，イニシャルコストの低下および装置の小型化を図ることができる。また，第２高周波電力と第３高周波電力の位相や周波数やパワーを，それぞれプロセスに応じて容易に変更できる。その結果，被処理体の膜質や大きさ等に応じたプラズマの制御が可能になり，被処理体に均一な処理を施すことができる。
【００１０】
さらに，前記第３高周波電源は、前記第１電極に前記第１高周波電力が印加された後、前記第１電極に前記第３高周波電力を印加し、前記第２高周波電源は、前記第１電極に前記第３高周波電力が印加された後、前記第２電極に前記第２高周波電力を印加することが好ましい。
【００１１】
また，本発明の第２の観点によれば，処理室内に対向配置された第１電極と第２電極とを備え，第１電極に第１高周波電力を印加し，第２電極に第１高周波電力よりも低い周波数の第２高周波電力を印加して処理室内にプラズマを生成し，第２電極上に載置された被処理体にプラズマ処理を施すプラズマ処理方法であって，第１電極に第１高周波電力を印加する第１工程と，第１工程の後に，第１電極に第１高周波電力の周波数よりも低く第２高周波電力の周波数以上の周波数の第３高周波電力を印加し，第１高周波電力と第３高周波電力とを重畳させる第２工程と，第２工程の後に，第２電極に第２高周波電力を印加する第３工程とを含み，さらに第２高周波電力の位相と第３高周波電力の位相との位相差を調整する第４工程を含むことを特徴とする，プラズマ処理方法が提供される。
【００１２】
かかる構成によれば，第１電極に第１高周波電力と第３高周波電力とを順次印加した後に，第２電極に第２高周波電力が印加される。さらに，第２高周波電力と第３高周波電力の位相差が調整される。このため，プラズマの着火，プラズマの安定生成，被処理体へのプラズマの均一な導入を容易かつ確実に行うことができる。
【００１３】
【発明の実施の形態】
以下に，添付図面を参照しながら本発明にかかるプラズマ処理装置およびプラズマ処理方法を，プラズマエッチング装置およびプラズマエッチング方法に適用した好適な実施の一形態について，詳細に説明する。
【００１４】
（１）エッチング装置の構成
まず，図１を参照しながら，本発明を適用可能なエッチング装置１００について概説する。エッチング装置１００の処理室１０２は，導電性の気密な処理容器１０４内に形成されている。処理容器１０４は，保安接地されている。また，処理室１０２内には，上部電極（第１電極）１０６と下部電極（第２電極）１０８とが対向配置されている。上部電極１０６と下部電極１０８は，それぞれ導電性材料から形成されている。また，下部電極１０８は，ウェハＷの載置台を兼ねている。また，上部電極１０６と下部電極１０８には，それぞれ後述する電力供給系が接続されている。また，処理室１０２内には，処理ガスがガス供給経路１１０を介して導入される。また，処理室１０２内のガスは，排気経路１１２を介して排気される。
【００１５】
（２）電力供給系の構成
次に，上部電極１０６および下部電極１０８への基本的な電力供給構成について説明する。上部電極１０６には，第１高周波電源１１４がローパス（低域通過）フィルタ１１６，第１整合器１１８，キャパシタンス１２０を介して接続されている。かかる構成により，上部電極１０６には，所定周波数，例えば６０ＭＨｚで５ｋＷの第１高周波電力を印加できる。ただし，キャパシタンス１２０は，第１高周波電力を選択的に通過させるとともに，後述する第３高周波電力の第１整合器１１８への進入を防止する。また，下部電極１０８には，第２高周波電源１２２が第２整合器１２４を介して接続されている。かかる構成により，下部電極１０８には，第１高周波電力の周波数よりも低い周波数，例えば２ＭＨｚで５ｋＷの第２高周波電力を印加できる。なお，上記各構成は，キャパシタンス１２０が設けられていることを除き，従来の装置と同様である。
【００１６】
次に，本発明の中核をなす電力供給系について説明する。上部電極１０６には，上述した第１高周波電源１１４に加え，本実施の形態の特徴である第３高周波電源１２６が第３整合器１２８，バンドパス（帯域通過）フィルタ１３０を介して接続されている。かかる構成により，上部電極１０６には，第１高周波電力の周波数よりも低く第２高周波電力の周波数以上の周波数，あるいは第２高周波電力の周波数と同一の周波数の第３高周波電力と，上述した第１高周波電力との重畳高周波電力を印加できる。なお，本実施の形態では，第３高周波電力は，例えば第２高周波電力の周波数と同一の２ＭＨｚで２ｋＷに設定されている。また，第３高周波電源１２６は，上部電極１０６とキャパシタンス１２０との間に接続されている。このため，上述したように，第３高周波電力が第１整合器１１８に進入せず，第１整合器１１８の整合動作に悪影響を及ぼすことがない。また，バンドパスフィルタ１３０は，上記２ＭＨｚの第３高周波電力を選択的に通過させるとともに，第１高周波電力の第３整合器１２８への進入を防止するフィルタである。このため，第１高周波電力が第３整合器１２８に進入せず，第３整合器１１８の整合動作の動作不良が生じることがない。
【００１７】
また，第２高周波電源１２２と第３高周波電源１２６には，位相制御器１３２が接続されている。位相制御器１３２は，第２整合器１２４での第２高周波電力の位相と，第３整合器１２８での第３高周波電力の位相とを検出する。さらに，位相制御器１３２は，検出された第２高周波電力の位相と第３高周波電力の位相とに基づいて，第２高周波電源１２２と第３高周波電源１２６を制御する。かかる制御により，第２高周波電力の位相と第３高周波電力の位相に所定の位相差を生じさせることができる。その結果，プラズマの状態やプロセスに応じてプラズマを制御でき，ウェハＷに均一な処理を施すことができる。
【００１８】
（３）エッチング処理
次に，上述したエッチング装置１００を用いたエッチング処理について説明する。まず，下部電極１０８上にウェハＷを載置する。ウェハＷの被処理面には，ＳｉＯ_２膜が形成されている。次いで，処理室１０２内に処理ガス，例えばフルオロカーボン系ガスを導入する。同時に，処理室１０２内を真空引きし，所定の減圧雰囲気に維持する。
【００１９】
上記諸条件が整った後，まず第１高周波電源１１４から出力される６０ＭＨｚの第１高周波電力を上部電極１０６に印加する。かかる電力の印加により，処理ガスがプラズマ化する。ただし，第１高周波電力の印加だけでは，すでに説明したように，第１高周波電力の周波数が高いために，生成されるプラズマの分布が不均一になり易い。そこで，第１高周波電力の印加後，第３高周波電源１２６から出力される２ＭＨｚの第３高周波電力を上部電極１０６に印加する。かかる電力の印加により，上部電極１０６には，第１高周波電力と第３高周波電力とが重畳された高周波電力が印加される。その結果，上記プラズマの分布が均一化される。さらに，第３高周波電力の印加後，第２高周波電源１２２から出力される２ＭＨｚの第２高周波電力を下部電極１０８に印加する。かかる電力の印加により，プラズマがウェハＷに均一に導入される。その結果，ウェハＷのＳｉＯ_２膜に，高エッチングレートで均一な処理を施すことができ，所定形状のコンタクトホールを形成できる。また，ウェハＷにプラズマを均一に導入できるので，プラズマの偏りに伴うウェハＷの損傷を防止できる。
【００２０】
また，上記構成によれば，第２高周波電源１２２と第３高周波電源１２６とが個別独立に設けられている。このため，パワースプリッタを使用せずに第２高周波電力および第３高周波電力を供給できる。その結果，装置構成を簡素化でき，かつイニシャルコストも減少させることができる。また，第２高周波電力と第３高周波電力とを独立して制御できる。その結果，高周波電力の制御性が向上し，処理をより均一に行うことができる。さらに，プロセスマージンも拡大できる。
【００２１】
以上，本発明の好適な実施の一形態について，添付図面を参照しながら説明したが，本発明はかかる構成に限定されるものではない。特許請求の範囲に記載された技術的思想の範疇において，当業者であれば，各種の変更例および修正例に想到し得るものであり，それら変更例および修正例についても本発明の技術的範囲に属するものと了解される。
【００２２】
【発明の効果】
本発明によれば，プラズマ生成用の第１高周波電力に重畳する第３高周波電力とバイアス用の第２高周波電力の位相，周波数，パワーを個別独立かつ容易に変えることができる。その結果，プラズマの制御を容易かつ的確に行うことができる。
【図面の簡単な説明】
【図１】本発明を適用可能なエッチング装置を示す概略的な断面図である。
【符号の説明】
１００エッチング装置
１０２処理室
１０６上部電極
１０８下部電極
１１４第１高周波電源
１２２第２高周波電源
１２６第３高周波電源
１３２位相制御器
Ｗウェハ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus and a plasma processing method.
[0002]
[Prior art]
Conventionally, various plasma processing, for example, plasma etching processing is performed in the manufacturing process of a semiconductor device. The plasma etching process is performed using a plasma etching apparatus. As the apparatus, a parallel plate type apparatus in which an upper electrode and a lower electrode are arranged to face each other in a processing chamber is widely used. In such an apparatus, the processing gas introduced into the processing chamber is turned into plasma by the application of the first high-frequency power to the upper electrode. Furthermore, the plasma is drawn into the object by applying a second high frequency power having a frequency lower than the first high frequency power to the lower electrode. Therefore, a predetermined etching process is performed on an object to be processed placed on the lower electrode, for example, a semiconductor wafer (hereinafter referred to as “wafer”).
[0003]
Recently, with the trend toward ultra-miniaturization and ultra-high integration of semiconductor devices, ultra-fine processing is also required for etching processing. Furthermore, in order to improve throughput, speeding up of processing is required. For this reason, various improvements of the plasma etching apparatus have been attempted in order to achieve such technical requirements. For example, in an etching apparatus for an oxide film (SiO₂ film), the etching rate is improved by increasing the frequency of the first high-frequency power for plasma generation to a frequency higher than the conventional frequency of about 13.56 MHz, for example, 60 MHz. Techniques to make it have been proposed. However, when the first high frequency power having such a frequency is used, the plasma distribution tends to be non-uniform. Therefore, a technique has been proposed in which the voltage of the second high-frequency power is further divided by a power splitter, a part of the divided power is applied to the lower electrode, and a part is superimposed on the first high-frequency power. When plasma is generated by such superposed high-frequency power, the plasma distribution is made uniform. Therefore, even when processing is performed using the first high-frequency power having a high frequency, it is possible to perform uniform processing while improving the etching rate. In addition, wafer damage is reduced. For this reason, it is possible to perform ultra-fine processing on the wafer with a high yield.
[0004]
[Problems to be solved by the invention]
Recently, from the viewpoint of improving productivity, it is required to process a large-diameter wafer. For this reason, in the etching process, it is necessary to uniformly generate plasma in a processing chamber having a large volume and to introduce the plasma uniformly over the entire surface of a large wafer. As a result, as the wafer diameter increases, it is required to apply higher power (electric power) of high frequency power to the upper electrode and the lower electrode. However, since the power splitter is a kind of transformer, when the power of the second high-frequency power is increased, the wire material and the core material which are constituent members are enlarged. The power splitter is generally provided near the lower electrode from the viewpoint of improving the power supply efficiency. As a result, there is a problem that the etching apparatus becomes large and it is difficult to reduce the footprint.
[0005]
The core material is manufactured according to the power of the high frequency power, the frequency to be used, and the like. Furthermore, the core material has a special configuration as the power of the applied high-frequency power increases, and the versatility decreases. For this reason, if a power splitter for high power is used, there is a problem that the production cost of the apparatus increases.
[0006]
In the above conventional technique, the second high-frequency power is divided by the power splitter. In the power splitter, the voltage applied to the upper electrode and the lower electrode can be set to a predetermined voltage ratio. However, during processing, the ratio of the impedance seen from the upper electrode to the impedance seen from the lower electrode changes due to the action of the generated plasma. For this reason, when the power splitter is used, the power of the divided second high-frequency power applied to the upper electrode and the lower electrode changes due to the change in the impedance ratio. As a result, there is a problem that it becomes difficult to control the power of the divided second high-frequency power, and further uniform processing cannot be achieved.
[0007]
The present invention has been made in view of the above-described problems of conventional techniques. An object of the present invention is to provide a new and improved plasma processing apparatus and plasma processing method capable of solving the above problems and other problems.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, according to a first aspect of the present invention, as in the first aspect of the present invention, high-frequency power is applied to each of the first electrode and the second electrode that are opposed to each other in the processing chamber. A first high frequency power source for applying a first high frequency power to the first electrode in a plasma processing apparatus for generating plasma in the processing chamber and applying a plasma treatment to an object to be processed placed on the second electrode; the second high frequency power source and the third high frequency having a frequencyhigher than the frequency of the second high frequency power lower than the frequency of the first high-frequency power applied to the second high-frequency power having a frequency lower than the first high-frequency power to the second electrode A third high-frequency power source for outputting power and superimposing the third high-frequency power on the first high-frequency power; and a second high-frequency power source and a third high-frequency power source connected to the second high-frequency power phase and the third high-frequency power phase; Control means for adjusting the phase difference of , Characterized in that it comprises a plasma processing apparatus is provided.
[0009]
According to such a configuration, the third high-frequency power superimposed on the first high-frequency power is output from the third high-frequency power supply that is independent from the second high-frequency power supply. According to such a configuration, it is possible to apply superimposed high frequency power to the first electrode without providing a power splitter. As a result, the initial cost can be reduced and the apparatus can be downsized. Further, the phase, frequency, and power of the second high-frequency power and the third high-frequency power can be easily changed according to the process. As a result, the plasma can be controlled according to the film quality and size of the object to be processed, and the object to be processed can be uniformly processed.
[0010]
Further,the third high frequency power supply applies the third high frequency power to the first electrode after the first high frequency power is applied to the first electrode, and the second high frequency power supply includes the first electrode. after the third high-frequency power is applied to the child applies the second high-frequency power to the second electrode is preferable.
[0011]
According to the second aspect of the presentinvention, a first electrode and a second electrode disposed opposite to theprocessing chamber, the first high-frequency power is applied to the first electrode, the first to the second electrode A plasma processing method for generating a plasma in a processing chamber by applying a second high-frequency power having a frequency lower than the high-frequency power, and performing a plasma treatment on an object to be processed placed on a second electrode. Applying a first high-frequency power to the first electrode, and applying a third high-frequency power having a frequency lower than the frequency of the first high-frequency power and higher than the frequency of the second high-frequency power to the first electrode after the first step; A second step of superimposing the first high-frequency power and the third high-frequency power; a third step of applying the second high-frequency power to the second electrode after the second step; Including a fourth step of adjusting a phase difference with the phase of the third high-frequency power. The symptom, the plasma processing method is provided.
[0012]
According to this configuration, the first high frequency power and the third high frequency power are sequentially applied to the first electrode, and then the second high frequency power is applied to the second electrode. Further, the phase difference between the second high frequency power and the third high frequency power is adjusted. For this reason, it is possible to easily and reliably perform plasma ignition, stable plasma generation, and uniform introduction of plasma into the workpiece.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment in which a plasma processing apparatus and a plasma processing method according to the present invention are applied to a plasma etching apparatus and a plasma etching method will be described in detail with reference to the accompanying drawings.
[0014]
(1) Configuration of Etching Apparatus First, anetching apparatus 100 to which the present invention can be applied will be outlined with reference to FIG. Theprocessing chamber 102 of theetching apparatus 100 is formed in a conductive andairtight processing container 104. Theprocessing container 104 is grounded for safety. In theprocessing chamber 102, an upper electrode (first electrode) 106 and a lower electrode (second electrode) 108 are disposed to face each other. Theupper electrode 106 and thelower electrode 108 are each formed from a conductive material. Thelower electrode 108 also serves as a mounting table for the wafer W. Theupper electrode 106 and thelower electrode 108 are connected to a power supply system described later. A processing gas is introduced into theprocessing chamber 102 via agas supply path 110. Further, the gas in theprocessing chamber 102 is exhausted through theexhaust path 112.
[0015]
(2) Configuration of Power Supply System Next, a basic power supply configuration to theupper electrode 106 and thelower electrode 108 will be described. A first high-frequency power source 114 is connected to theupper electrode 106 via a low-pass (low-pass)filter 116, afirst matching unit 118, and acapacitance 120. With this configuration, a first high frequency power of 5 kW at a predetermined frequency, for example, 60 MHz, can be applied to theupper electrode 106. However, thecapacitance 120 selectively allows the first high-frequency power to pass through and prevents the third high-frequency power, which will be described later, from entering thefirst matching unit 118. In addition, a second highfrequency power source 122 is connected to thelower electrode 108 via asecond matching unit 124. With this configuration, a lower frequency than the frequency of the first high frequency power, for example, a second high frequency power of 5 kW at 2 MHz can be applied to thelower electrode 108. Each of the above configurations is the same as that of the conventional apparatus except that acapacitance 120 is provided.
[0016]
Next, the power supply system that forms the core of the present invention will be described. In addition to the first highfrequency power supply 114 described above, a third highfrequency power supply 126 that is a feature of the present embodiment is connected to theupper electrode 106 via athird matching unit 128 and a bandpass (bandpass)filter 130. Yes. With this configuration, theupper electrode 106 has the third high frequency power having a frequency lower than the frequency of the first high frequency power and higher than the frequency of the second high frequency power, or the same frequency as the frequency of the second high frequency power. A high frequency power superimposed with one high frequency power can be applied. In the present embodiment, the third high frequency power is set to 2 kW at 2 MHz, for example, which is the same as the frequency of the second high frequency power. The third highfrequency power supply 126 is connected between theupper electrode 106 and thecapacitance 120. For this reason, as described above, the third high-frequency power does not enter thefirst matching unit 118, and the matching operation of thefirst matching unit 118 is not adversely affected. The band-pass filter 130 is a filter that selectively passes the second high-frequency power of 2 MHz and prevents the first high-frequency power from entering thethird matching unit 128. For this reason, the first high-frequency power does not enter thethird matching unit 128, and the operation of the matching operation of thethird matching unit 118 does not occur.
[0017]
Aphase controller 132 is connected to the second highfrequency power supply 122 and the third highfrequency power supply 126. Thephase controller 132 detects the phase of the second high frequency power in thesecond matching unit 124 and the phase of the third high frequency power in thethird matching unit 128. Furthermore, thephase controller 132 controls the second highfrequency power supply 122 and the third highfrequency power supply 126 based on the detected phase of the second high frequency power and the phase of the third high frequency power. By such control, a predetermined phase difference can be generated between the phase of the second high-frequency power and the phase of the third high-frequency power. As a result, the plasma can be controlled in accordance with the plasma state and process, and the wafer W can be uniformly processed.
[0018]
(3) Etching Process Next, an etching process using the above-describedetching apparatus 100 will be described. First, the wafer W is placed on thelower electrode 108. An SiO₂ film is formed on the surface to be processed of the wafer W. Next, a processing gas such as a fluorocarbon gas is introduced into theprocessing chamber 102. At the same time, the inside of theprocessing chamber 102 is evacuated to maintain a predetermined reduced pressure atmosphere.
[0019]
After the above conditions are satisfied, first, a 60 MHz first high frequency power output from the first highfrequency power supply 114 is applied to theupper electrode 106. By applying such power, the processing gas is turned into plasma. However, when only the first high-frequency power is applied, the distribution of the generated plasma tends to be non-uniform because the frequency of the first high-frequency power is high as described above. Therefore, after the application of the first high frequency power, the second high frequency power of 2 MHz output from the third highfrequency power supply 126 is applied to theupper electrode 106. By applying such power, high frequency power in which the first high frequency power and the third high frequency power are superimposed is applied to theupper electrode 106. As a result, the plasma distribution is made uniform. Further, after the application of the third high frequency power, the second high frequency power of 2 MHz output from the second highfrequency power supply 122 is applied to thelower electrode 108. Plasma is uniformly introduced into the wafer W by the application of such electric power. As a result, the SiO₂ film of the wafer W can be uniformly processed at a high etching rate, and a contact hole having a predetermined shape can be formed. In addition, since the plasma can be uniformly introduced into the wafer W, damage to the wafer W due to the plasma bias can be prevented.
[0020]
Further, according to the above configuration, the second highfrequency power supply 122 and the third highfrequency power supply 126 are provided independently. Therefore, the second high frequency power and the third high frequency power can be supplied without using a power splitter. As a result, the apparatus configuration can be simplified and the initial cost can be reduced. Further, the second high frequency power and the third high frequency power can be controlled independently. As a result, the controllability of the high frequency power is improved and the processing can be performed more uniformly. In addition, the process margin can be expanded.
[0021]
The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such a configuration. Within the scope of the technical idea described in the claims, those skilled in the art will be able to conceive of various changes and modifications, and these changes and modifications are also within the technical scope of the present invention. It is understood that it belongs to.
[0022]
【The invention's effect】
According to the present invention, the phase, frequency, and power of the third high-frequency power superimposed on the first high-frequency power for plasma generation and the second high-frequency power for bias can be changed independently and easily. As a result, plasma can be controlled easily and accurately.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing an etching apparatus to which the present invention can be applied.
[Explanation of symbols]
DESCRIPTION OFSYMBOLS 100Etching apparatus 102Processing chamber 106Upper electrode 108Lower electrode 114 1st highfrequency power supply 122 2nd highfrequency power supply 126 3rd highfrequency power supply 132 Phase controller W Wafer

Claims

Translated fromJapanese

処理室内に対向配置された第１電極と第２電極との各々に高周波電力を印加して前記処理室内にプラズマを生成し，前記第２電極上に載置された被処理体にプラズマ処理を施すプラズマ処理装置において：
前記第１電極に第１高周波電力を印加する第１高周波電源と；
前記第２電極に前記第１高周波電力よりも低い周波数の第２高周波電力を印加する第２高周波電源と；
前記第１高周波電力の周波数よりも低く前記第２高周波電力の周波数よりも高い周波数の第３高周波電力を出力し，前記第１高周波電力に前記第３高周波電力を重畳する第３高周波電源と；
前記第２高周波電源と前記第３高周波電源に接続され，前記第２高周波電力の位相と前記第３高周波電力の位相との位相差を調整する位相制御手段と；
を備えることを特徴とする，プラズマ処理装置。A high-frequency power is applied to each of the first electrode and the second electrode that are arranged opposite to each other in the processing chamber to generate plasma in the processing chamber, and plasma processing is performed on the object to be processed placed on the second electrode. In the plasma processing equipment to be applied:
A first high frequency power supply for applying a first high frequency power to the first electrode;
A second high frequency power supply for applying a second high frequency power having a frequency lower than the first high frequency power to the second electrode;
And outputting a third high-frequency power having a frequencyhigher than the frequency of the second RF power lower than the frequency of the first high frequency power, and a third high-frequency power source for superimposing the third high-frequency power to the first high-frequency power;
Phase control means connected to the second high-frequency power source and the third high-frequency power source to adjust a phase difference between the phase of the second high-frequency power and the phase of the third high-frequency power;
A plasma processing apparatus comprising:

前記第３高周波電源は、前記第１電極に前記第１高周波電力が印加された後、前記第１電極に前記第３高周波電力を印加し、 The third high-frequency power source applies the third high-frequency power to the first electrode after the first high-frequency power is applied to the first electrode,
前記第２高周波電源は、前記第１電極に前記第３高周波電力が印加された後、前記第２電極に前記第２高周波電力を印加する請求項１に記載のプラズマ処理装置。 2. The plasma processing apparatus according to claim 1, wherein the second high frequency power supply applies the second high frequency power to the second electrode after the third high frequency power is applied to the first electrode.

前記第２工程にて、前記第１電極に前記第１高周波電力の周波数よりも低く前記第２高周波電力の周波数よりも高い周波数の第３高周波電力を印加すること； Applying a third high-frequency power having a frequency lower than the frequency of the first high-frequency power and higher than the frequency of the second high-frequency power to the first electrode in the second step;
を特徴とする，請求項３に記載のプラズマ処理方法。 The plasma processing method according to claim 3, wherein: