JPS62143418A - Thin film forming device - Google Patents

Abstract

PURPOSE:To make the titled device small in size to one half or thereabout by a method wherein, in a microwave plasma deposition device, two sets of electrodes are positioned opposing to each other so that an electric field vertical to a magnetic field is generated in a vacuum chamber. CONSTITUTION:The titled device is formed with a vacuum chamber 1 in which a chemical vapor-deposition method is performed, a discharge tube 2 wherein a microwave discharge is performed, a coil 3 to be used to apply a magnetic field in the discharge tube 2, a waveguide 7 with which microwaves are introduced, and a microwave generating device 8. At that time, a substrate stand 9 whereon a substrate 10 is placed is provided in the vacuum chamber 1, and an electrode 4 with which an electric field is applied between the substrate stand 9 and the discharge tube 2. Then, discharge gas and reaction gas are introduced from a part tocated between the discharge tube 2 and the vacuum chamber 1 passing through a discharge gas introducing hole 6 and a reaction gas introducing hole 5, and they are jetted out into the discharge tube 2 and the vacuum chamber 1 from the inside shower. As a result, the titled device can be made small in size to one half or thereabout.

Description

【発明の詳細な説明】 〔発明の利用分野〕 本発明はマイクロ波プラズマを用いた薄膜形成装置に係
り、特に小型でかつ大面積処理が可能なマイクロ波プラ
ズマデポジション装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a thin film forming apparatus using microwave plasma, and particularly to a microwave plasma deposition apparatus that is small and capable of processing a large area.

〔発明の背景〕[Background of the invention]

従来の装置は、特開昭５９−３０１８号に記載のように
真空槽に放電管を設け、これにコイルをとり付は磁場を
印加し、さらに導波管を通じて電子サイクロトロン周波
数と等しい周波数のマイクロ波を導入して放電を行い、
それによって真空槽内にガス導入口から導入された反応
ガスを分解し真空槽内に設置された基板上に化学蒸着を
行うようになっていた。しかし、この方式では電子は磁
力線に束縛されており、放電管から出た磁力線」−での
み反応ガスの分解が進むため成膜できる面積が限られて
いた。従って大面積を処理するためには大型の放電管お
よびその内部に充分強い磁場を発生させるための大型の
コイルを必要とし装置が大型かつ高価なものとならざる
を得なかった。The conventional device, as described in Japanese Patent Application Laid-Open No. 59-3018, installs a discharge tube in a vacuum chamber, attaches a coil to it, applies a magnetic field, and then transmits a microelectronic device with a frequency equal to the electron cyclotron frequency through a waveguide. A wave is introduced to generate a discharge,
Thereby, the reaction gas introduced into the vacuum chamber from the gas inlet is decomposed and chemical vapor deposition is performed on the substrate placed in the vacuum chamber. However, in this method, the electrons are bound by the magnetic lines of force, and the decomposition of the reactant gas proceeds only by the lines of magnetic force emanating from the discharge tube, which limits the area on which a film can be formed. Therefore, in order to treat a large area, a large discharge tube and a large coil are required to generate a sufficiently strong magnetic field inside the discharge tube, making the apparatus large and expensive.

〔発明の目的〕[Purpose of the invention]

本発明の目的は大面積に成膜するに際し、かかる装置の
大型化を回避し、小型で大面積成膜が可能な装置を提供
することにある。An object of the present invention is to avoid increasing the size of such an apparatus when forming a film over a large area, and to provide a compact apparatus capable of forming a film over a large area.

〔発明の概要〕[Summary of the invention]

マイクロ波プラズマを用いた化学蒸着装置では上記のよ
うに電子サイクロトロン共鳴を起すために印加した磁場
に電子が束縛され、成膜域が狭くなる。磁場中の荷電粒
子の運動は一般に磁力線にそったらせん運動となり、回
転周波数ｆは２　πｍ 但し、 Ｂ：磁束密度 ｍ：粒子の質量 ｑ：粒子の電荷 となる。ここに磁場と垂直方向の電場Ｅが存在すると、
荷電粒子は回転の一方向に加速され、逆方向に減速させ
られる。その結果第２図に示すように電場、磁場に対し
て垂直な方向ヘトリフトする。In a chemical vapor deposition apparatus using microwave plasma, electrons are bound by the magnetic field applied to cause electron cyclotron resonance as described above, resulting in a narrow film formation area. The motion of charged particles in a magnetic field generally becomes a spiral motion along the lines of magnetic force, and the rotation frequency f is 2 πm. However, B: magnetic flux density m: mass of particle q: charge of particle. If there is an electric field E in the direction perpendicular to the magnetic field, then
Charged particles are accelerated in one direction of rotation and decelerated in the opposite direction. As a result, as shown in FIG. 2, there is a lift in a direction perpendicular to the electric and magnetic fields.

その時、正の電荷を持つ粒子も負の電荷を持つ粒子も同
じ方向に移動し、そのドリフト速度ＷｏはＷｏ＝１０’
　　（釧／秒） 但し、 Ｅ：ｉｉｉ場の強さくＶ／■） Ｂ：磁場の強さくＧａｕｓｓ） となる。At that time, both positively charged particles and negatively charged particles move in the same direction, and their drift speed Wo is Wo=10'
(Ten/sec) However, E: iii field strength V/■) B: magnetic field strength Gauss).

したがって放電管と基板の間に磁場と直交するｆ！場を
発生するようなＷ１極を設けこれに電圧を加えると放電
管より出た電子をドリフトさせることができ、成膜域を
動かすことができる。前記電極が作る電場と直交し、か
つ、磁場とも直交するような電場を発生するような電極
を設ければこの電極と前記電極が作る電場のベクトル和
が実効電場として働くため、成膜域を２次元で自由に動
かすことが可能となる。Therefore, f! is perpendicular to the magnetic field between the discharge tube and the substrate. By providing a W1 pole that generates a field and applying a voltage to it, electrons emitted from the discharge tube can be caused to drift, and the film forming area can be moved. If an electrode is provided that generates an electric field that is orthogonal to the electric field generated by the electrode and also perpendicular to the magnetic field, the vector sum of the electric field generated by this electrode and the electrode acts as an effective electric field, so that the film formation area can be It becomes possible to move freely in two dimensions.

そこで小型の放電管を有するマイクロ波プラズマ化学蒸
着装置で大面積の成膜を行うには放電管と基板の間に、
磁場と直交する？Ｉｔ！＆Ｉを発生させる２組の電極を
設け、これに適宜、？ｌ！圧を印加し、基板上の成膜域
を順次移動し２基−板面全体に成膜すればよい。Therefore, in order to form a film over a large area using a microwave plasma chemical vapor deposition system with a small discharge tube, there is a need to
Orthogonal to the magnetic field? It! Two sets of electrodes that generate &I are provided, and ? l! The film may be deposited on the entire surface of the two substrates by applying pressure and moving sequentially through the film formation areas on the substrates.

マイクロ波プラズマ化学蒸着で形成する薄膜としては、
アモルファスシリコン膜、酸化ケイ素膜。Thin films formed by microwave plasma chemical vapor deposition include:
Amorphous silicon film, silicon oxide film.

窒化ケイ素膜等がある。目的とする膜の種類に応じて反
応ガスおよび放電ガスを変えればよい。例えば酸化ケイ
素膜の場合には放電ガスとして酸素ガス、反応ガスとし
てモノシラン又はジシランガスを用いるか、もしくは放
電ガスとしてアルゴンガスを、反応ガスとして亜酸化窒
素とモノシラン又はジシランのいずれか１つを用いれば
よい。窒化ケイ素膜の場合は放電ガスとして窒素を、反
応ガスとしてモノシラン又はジシランを用いる。窒化ケ
イ素膜は、放電ガスとしてアルゴンガスを用い、反応ガ
スとしてモノシラン、ジシランのいずれかと、アンモニ
アガスを用いても作成することができる。アモルファス
シリコン膜は放電ガスとしてアルゴンガスを用い、反応
ガスとしてモノシランまたはジシランおよびドーピング
ガスとしてＢ２Ｈ６またはＰＨ３を用いればよい。There are silicon nitride films, etc. The reaction gas and discharge gas may be changed depending on the type of desired film. For example, in the case of a silicon oxide film, oxygen gas is used as the discharge gas and monosilane or disilane gas is used as the reaction gas, or argon gas is used as the discharge gas and nitrous oxide and either monosilane or disilane are used as the reaction gas. good. In the case of a silicon nitride film, nitrogen is used as the discharge gas and monosilane or disilane is used as the reaction gas. The silicon nitride film can also be created using argon gas as the discharge gas and either monosilane or disilane and ammonia gas as the reaction gas. For the amorphous silicon film, argon gas may be used as a discharge gas, monosilane or disilane may be used as a reactive gas, and B2H6 or PH3 may be used as a doping gas.

装置の材質としては反応室は一般の真空装置と同じくス
テンレススチールもしくはアルミニラ１１でよい、放電
管はマイクロ波が通るため絶縁材料でなくてはならず、
石英、アルミナ、窒化ケイ素等のセラミック材料であれ
ばよい。As for the material of the device, the reaction chamber can be made of stainless steel or aluminum 11, which is the same as in general vacuum devices, and the discharge tube must be made of an insulating material because microwaves pass through it.
Any ceramic material such as quartz, alumina, silicon nitride, etc. may be used.

真空排気系は放電ガスや反応ガスを流しながら高真空を
保つ必要があるので大容量の高真空排気装置が必要であ
り、かつ反応室と排気装置間のコンダクタンスは充分大
きくとる必要がある。ガスの総流量が２０　ｓｅｃｍ程
度の装置では毎秒５００Ｑ程度の排気能力のポンプがあ
ればよい。ポンプの種類としては分子ターボポンプか拡
散ポンプが適している。The vacuum evacuation system needs to maintain a high vacuum while flowing discharge gas and reaction gas, so a large-capacity high-vacuum evacuation device is required, and the conductance between the reaction chamber and the evacuation device needs to be sufficiently large. For an apparatus with a total gas flow rate of about 20 seconds, a pump with an exhaust capacity of about 500Q per second is sufficient. As for the type of pump, a molecular turbo pump or a diffusion pump is suitable.

電子にサイクロトロン運動をさせるための磁場を発生さ
せるコイルは中心磁束密度が５００〜２０００ガウス程
度の磁場を発生できる必要がある。A coil that generates a magnetic field for causing electrons to perform cyclotron motion must be able to generate a magnetic field with a center magnetic flux density of approximately 500 to 2000 Gauss.

磁場が弱いとイオンの旋回半径が大きくなり器壁との衝
突で失活するイオンが増加してしまう。If the magnetic field is weak, the ion radius of gyration becomes large, and more ions are deactivated by collision with the vessel wall.

マイクロ波の周波数ｆは磁束密度Ｂ、ｆｆｌ子貿量ｍ、
電子電荷ｅとすると １ｅｌＢ の共鳴条件を満足する必要がある。マイクロ波電源の出
力は１００Ｗ〜１００ＯＷであればよい。The frequency f of the microwave is the magnetic flux density B, the ffl magnetic flux m,
If the electronic charge is e, it is necessary to satisfy the resonance condition of 1elB. The output of the microwave power source may be 100W to 100OW.

成膜域を移動させるために印加する磁場と直交する電場
の強さはＯ〜２００Ｖ／ａｍで変化できればよい。直交
する２組の電極に位相を９０″ずらした正弦波を印加す
ると成膜域は基板平面上で円を描いて移動する。印加す
る正弦波のピーク電圧を小さくするとその円の半径は小
さくなり、大きくすると円半径は大きくなる。そこでで
きた膜の厚さが均一となるように加える正弦波のピーク
電圧を制御すればよい。以上は円形に成膜域を移動する
場合であるが、基板が四角や三角等の場合はそれぞれ四
角や三角の形で成膜域を移動してもよい。その時は成膜
域を移動する線を座標上にとりそのＸ座標、Ｘ座標に、
直交する電極に加える電圧を対応させればよい。It is sufficient that the strength of the electric field orthogonal to the magnetic field applied to move the film forming region can be varied between 0 and 200 V/am. When a sine wave with a phase shift of 90'' is applied to two orthogonal sets of electrodes, the film forming area moves in a circle on the substrate plane.If the peak voltage of the applied sine wave is reduced, the radius of the circle becomes smaller. , the radius of the circle becomes larger.Then, the peak voltage of the sine wave to be applied should be controlled so that the thickness of the film formed is uniform.The above is a case where the film formation area is moved circularly, but the If it is square or triangular, the film forming area may be moved in the shape of a square or triangle, respectively.In that case, the line that moves the film forming area is set on the coordinates, and its X coordinate,
It is sufficient to match the voltages applied to the orthogonal electrodes.

〔発明の実施例〕[Embodiments of the invention]

以下、本発明の一実施例を第１図により説明する。本装
置は化学蒸着を行う真空槽１と、マイクロ波放電を行う
放電管２と、放電管２に磁場を印加するためのコイル３
と、マイクロ波を導入する導波管７と、マイクロ波発生
装置８、および、高真空排気装置より成っている。真空
槽１内には基板１０をのせる基板台９があり、ｊＡ板台
９と放電管２の間にｆ！！場を印加する電極４がある。An embodiment of the present invention will be described below with reference to FIG. This device consists of a vacuum chamber 1 for chemical vapor deposition, a discharge tube 2 for microwave discharge, and a coil 3 for applying a magnetic field to the discharge tube 2.
, a waveguide 7 for introducing microwaves, a microwave generator 8, and a high vacuum exhaust device. Inside the vacuum chamber 1 is a substrate stand 9 on which a substrate 10 is placed, and between the jA plate stand 9 and the discharge tube 2 is f! ! There is an electrode 4 for applying the field.

放電ガス、および反応ガスは、放電管と真空槽の間から
それぞれ放電ガス導入ロ６２反応ガス導入口５を通して
導入され内部のシャワーより、放電管内、および、真空
槽内へ噴出される。The discharge gas and the reaction gas are introduced from between the discharge tube and the vacuum chamber through the discharge gas introduction hole 62 and the reaction gas introduction port 5, respectively, and are ejected from the internal shower into the discharge tube and the vacuum chamber.

以下１本装置を用いてアモルファスシリコンをガラス基
板上に形成した例について述べる。An example in which amorphous silicon was formed on a glass substrate using one of the apparatuses will be described below.

３００ＩＩＩＩＩ角のガラス基板を基板台９上に取り付
け、真空槽内を高真空（１０”−’Ｔｏｒｒ）に排気し
た。A 300mm square glass substrate was mounted on the substrate stand 9, and the inside of the vacuum chamber was evacuated to a high vacuum (10''-'Torr).

次に放電ガスとしてアルゴンガス１０１０５ｅ、反応ガ
スとしてモノシランガス６３ｃｃＩｌをそれぞれ放電ガ
ス導入口６および反応ガス導入口５より導入し。Next, argon gas 10105e as a discharge gas and monosilane gas 63ccIl as a reaction gas were introduced through the discharge gas inlet 6 and the reaction gas inlet 5, respectively.

真空槽内を６×１０″″’Ｔｏｒｒに保った。基板台９
に内蔵されたヒータにより基板を１８０℃に加熱し。The inside of the vacuum chamber was maintained at 6×10''' Torr. Board stand 9
The substrate was heated to 180°C using a built-in heater.

温度が安定したところでコイル３に電流を通じ放電管内
に、８７５ガウスの磁場を発生させた。コイル３の電流
が安定したところで、マイクロ波発生装置８（マグネト
ロン）により２．４５ＧＨｚのマイクロ波を発生させ、
導波管７により放電管２にマイクロ波２００Ｗを印加し
、放電を開始した。同時に電極４に第３図に示すような
電圧を繰り返し印加し、成膜を行った。その結果７５分
間の成膜時間で膜厚３０００人±２００人のアモルファ
スシリコン膜を３００ｍｍ角のガラス基板全面に渡って
形成することができた。When the temperature became stable, a current was passed through the coil 3 to generate a magnetic field of 875 Gauss inside the discharge tube. When the current in the coil 3 becomes stable, a microwave generator 8 (magnetron) generates a 2.45 GHz microwave.
A microwave of 200 W was applied to the discharge tube 2 through the waveguide 7 to start discharge. At the same time, a voltage as shown in FIG. 3 was repeatedly applied to the electrode 4 to form a film. As a result, an amorphous silicon film with a thickness of 3000 mm ± 200 mm could be formed over the entire surface of a 300 mm square glass substrate in a film forming time of 75 minutes.

これに対し、電極４に電圧を印加しない場合は放電管の
正面の直径１００ｍの領域に、７５分間で約３μｍのア
モルファスシリコンが形成されたがこの領域の外では膜
厚は急激に薄くなっており、直径６５ｍｍの放電管で形
成できる面積が約１００ｍφであることが示された。On the other hand, when no voltage was applied to electrode 4, about 3 μm of amorphous silicon was formed in a 100 m diameter area in front of the discharge tube in 75 minutes, but the film thickness rapidly became thinner outside this area. It was shown that the area that can be formed by a discharge tube with a diameter of 65 mm is approximately 100 mφ.

本実施例で形成したアモルファスシリコン膜は光学バン
ドギャップが約１．８ｅＶで、光導電率が１．２Ｘ１０
−’Ｓ−ローエ、暗導電率が９．８×１０−１０Ｓ　責
１’であり、特に高品質なものであった。本実施例によ
れば高品質のアモルファスシリコンを形成できる効果が
ある。The amorphous silicon film formed in this example has an optical band gap of approximately 1.8 eV and a photoconductivity of 1.2×10
-'S-Rohe, the dark conductivity was 9.8 x 10-10S, and it was of particularly high quality. According to this embodiment, there is an effect that high quality amorphous silicon can be formed.

〔発明の効果〕〔Effect of the invention〕

本発明によれば小型のマイクロ波プラズマ化学蒸着装置
で大面積処理ができるので装置の大きさを２分の１程度
に小型化でき、軽量化、低価格化に効果がある。According to the present invention, since a large area can be treated with a small microwave plasma chemical vapor deposition apparatus, the size of the apparatus can be reduced to about half, which is effective in reducing weight and cost.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の詳細な説明図、第２図は本発明の実施
例なる装置の断面図、第３図は本発明の実施例で電極に
印加した電圧のパターンを示す図である。FIG. 1 is a detailed explanatory diagram of the present invention, FIG. 2 is a sectional view of an apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing a pattern of voltages applied to electrodes in an embodiment of the present invention.

Claims (1)

【特許請求の範囲】 １、真空室と、該真空室の少なくとも一部に電子サイク
ロトロン共鳴を起こすことが可能なように設けられた磁
場を形成する手段とマイクロ波電力を供給する手段を有
し、さらに上記真空室内に放電ガスを導入する手段と、
上記真空室内に試料を保持する手段を備えて構成された
マイクロ波プラズマデポジション装置において、上記真
空室内に磁場と垂直に電場を発生するように電極を２組
対向させたことを特徴とする薄膜形成装置。 ２、特許請求の範囲第１項において、上記磁場と垂直に
上記電場を発生するように設置された電極に加える電圧
が時間的に変化することによつて成膜域を移動し、最終
的に膜厚のよく制御された薄膜を得ることを特徴とする
薄膜形成装置。[Scope of Claims] 1. A vacuum chamber, a means for forming a magnetic field provided to cause electron cyclotron resonance in at least a part of the vacuum chamber, and a means for supplying microwave power. , further comprising means for introducing discharge gas into the vacuum chamber;
A microwave plasma deposition apparatus comprising means for holding a sample in the vacuum chamber, characterized in that two sets of electrodes are opposed to each other so as to generate an electric field perpendicular to the magnetic field in the vacuum chamber. Forming device. 2. In claim 1, the voltage applied to the electrode installed perpendicularly to the magnetic field to generate the electric field is moved in the film forming area by changing over time, and finally A thin film forming apparatus characterized by obtaining a thin film with a well-controlled film thickness.