JPH1125894A - Plasma ion shower sample treating device and its method - Google Patents

Plasma ion shower sample treating device and its method

Info

Publication number
JPH1125894A
JPH1125894A JP9189284A JP18928497A JPH1125894A JP H1125894 A JPH1125894 A JP H1125894A JP 9189284 A JP9189284 A JP 9189284A JP 18928497 A JP18928497 A JP 18928497A JP H1125894 A JPH1125894 A JP H1125894A
Authority
JP
Japan
Prior art keywords
sample
electrode
target electrode
cations
target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP9189284A
Other languages
Japanese (ja)
Inventor
Hiroshi Akahori
宏 赤堀
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SHINKU DEVICE KK
Original Assignee
SHINKU DEVICE KK
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SHINKU DEVICE KK filed Critical SHINKU DEVICE KK
Priority to JP9189284A priority Critical patent/JPH1125894A/en
Publication of JPH1125894A publication Critical patent/JPH1125894A/en
Pending legal-status Critical Current

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Abstract

PROBLEM TO BE SOLVED: To enable correct SEM(scanning electron microscope) observation and X-ray analysis by preventing the charging on the surface of a sample, when the SEM observation and the X-ray analysis are conducted, without forming a conductive film such as a metal film or a carbon film on the surface of the sample. SOLUTION: An ion shower sample treating device has a vacuum tank 1 kept in a dilute gas state, a target electrode 2 to which negative electrode is applied, and a sample table arranged so as to face the target electrode 2 and for setting a sample (s) to be treated. An electrode 4 for applying a positive voltage to the target electrode 2 is arranged in the vicinity of the sample table 3, and the target electrode 2 is made of metal having low sputtering ratio to ion bombardment to be used as an electrode material for reflecting cations on the surface. The inside of the vacuum bath 1 is kept in a dilute gas state, plasma discharge is generated between the target electrode 2 and the positive electrode 4, cations generated by plasma discharge are reflected in the target electrode 2, and cations reflected in the target electrode 2 are irradiated as in a shower onto the sample (s) set on the sample table 3.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【0001】[0001]

【発明の属する技術分野】本発明は走査型電子顕微鏡や
微小部X線分析装置を利用して観察する試料を、その観
察に供し得るように前処理する装置と方法に関し、具体
的には、試料の表面が負に帯電するのを解消するための
処理装置と方法に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for pretreating a sample to be observed using a scanning electron microscope or a microscopic X-ray analyzer so that the sample can be used for the observation. The present invention relates to a processing apparatus and a method for preventing a surface of a sample from being negatively charged.

【0002】[0002]

【従来の技術】走査電子顕微鏡(SEM)や微小部X線
分析装置で試料の観察や分析を行うには、試料が電気の
良導体であることが条件となる。このため生物試料や無
機化合物のように電気的に不良導体である試料は、表面
に厚さ数十nmの薄い金属膜や炭素膜等の導体膜を形成
することにより、電気的に良導体化させたうえで観察に
供する必要がある。
2. Description of the Related Art In order to observe and analyze a sample with a scanning electron microscope (SEM) or a microscopic X-ray analyzer, the sample must be a good conductor of electricity. For this reason, samples that are electrically poor conductors such as biological samples and inorganic compounds can be made electrically conductive by forming a thin metal film or carbon film with a thickness of several tens of nm on the surface. Must be used for observation.

【0003】このような試料表面への導体膜の被着に
は、一般に真空蒸着装置やイオンスパッタリング装置等
が利用される。しかし、これらの装置によって試料表面
に導体膜を形成すると、試料表面の微細形状が、試料表
面に被着した導体粒子によって被覆され、真の表面観察
が不可能である。またそれが、X線分析の感度低下など
障害となる。
[0003] A vacuum evaporation apparatus, an ion sputtering apparatus, or the like is generally used for depositing a conductive film on the surface of a sample. However, when a conductor film is formed on the sample surface by these devices, the fine shape of the sample surface is covered by the conductive particles adhered to the sample surface, and true surface observation is impossible. In addition, this hinders the sensitivity of X-ray analysis.

【0004】[0004]

【発明が解決しようとしている課題】このような問題の
対策として、試料の表面に導体膜の被着を行わずに観察
する手段として、低加速電圧SEM観察法が提案されて
いる。しかし、この低加速電圧SEM観察法は、一般の
汎用型SEMによる観察では分解能が低く、電界放射型
SEMのような高価な装置によってのみ観察が可能であ
る。これは、表面を導体化してない試料では、表面が帯
電しやすいことによる。すなわち、SEMにおける帯電
現象は、試料表面を走査する1次電子が試料表面に蓄積
し、その電界によって、後から飛来する1次電子や放出
される二次電子が偏向され、この結果、正常な像の形成
を妨害されることによる。これにより、正確な試料表面
の観察の障害となる。
As a countermeasure for such a problem, a low-acceleration voltage SEM observation method has been proposed as a means for observing a sample surface without applying a conductive film thereon. However, this low-acceleration-voltage SEM observation method has low resolution in observation using a general-purpose SEM, and can be observed only with an expensive device such as a field emission SEM. This is because the surface of the sample whose surface is not made conductive is easily charged. That is, in the charging phenomenon in the SEM, the primary electrons that scan the sample surface accumulate on the sample surface, and the primary electrons that fly later and the secondary electrons that are emitted are deflected by the electric field. The image formation is disturbed. This hinders accurate observation of the sample surface.

【0005】表面を導体化していない試料の帯電防止法
としては、イオン銃を利用し、数kVに加速したアルゴ
ンイオンを試料に打ち込む方法がある。この方法は無機
化合物のように、イオン衝撃に対して破壊のおそれの無
い試料には有効である。しかし、生物試料のような、軟
質試料ではイオン衝撃による破壊損傷が起こり、観察用
試料としては利用できない。また、加速したイオンは直
進するため陰の部分は照射されず、表面の凹凸の大きな
試料には効果が無い。さらに、イオン銃を具備した照射
装置は操作が複雑で、且つ高価な装置であり、汎用的に
使用するためには、経済的な負担が大である。
As a method for preventing static charge on a sample whose surface is not made conductive, there is a method in which an ion gun is used to implant argon ions accelerated to several kV into the sample. This method is effective for a sample such as an inorganic compound which is not likely to be damaged by ion bombardment. However, a soft sample such as a biological sample causes destructive damage due to ion bombardment and cannot be used as an observation sample. In addition, since the accelerated ions travel straight, the shaded portion is not irradiated, and there is no effect on a sample having large surface irregularities. Furthermore, the irradiation device equipped with an ion gun is a complicated and expensive device to operate, and it is economically burdensome to use it for general purposes.

【課題を解決するための手段】[Means for Solving the Problems]

【0006】本発明は、前記のような従来の課題に鑑
み、試料表面に金属膜や炭素膜等の導体膜を形成するこ
となく、SEM観察、X線分析に試料を供するのに際し
て、試料表面の帯電を防止し、正確なSEM観察或いは
X線分析を可能とすることを目的とするものである。従
来の試料表面に導体膜を形成する方法は、試料の表面を
導体化し、一次電子の衝撃により二次電子を発生させる
手段であるが、これにより試料の表面に蓄積する電子を
アースに逃がすことが可能であった。これに対し本発明
は、試料の表面に金属膜や炭素膜等の導体膜を被着せず
に、SEMやX線分析のための試料として供する場合に
おいて、試料の表面での電子の蓄積を回避することをす
ることを目的とする。
The present invention has been made in view of the above-mentioned conventional problems, and provides a sample surface for SEM observation and X-ray analysis without forming a conductive film such as a metal film or a carbon film on the sample surface. It is an object of the present invention to prevent electrostatic charging and enable accurate SEM observation or X-ray analysis. The conventional method of forming a conductor film on the surface of a sample is to convert the surface of the sample into a conductor and generate secondary electrons by the impact of primary electrons.This method allows electrons accumulated on the surface of the sample to escape to the ground. Was possible. In contrast, the present invention avoids the accumulation of electrons on the surface of a sample when used as a sample for SEM or X-ray analysis without depositing a conductive film such as a metal film or a carbon film on the surface of the sample. The purpose is to do.

【0007】このような目的を達成するための本発明に
よるイオンシャワー試料処理装置は、希薄気体状態に維
持される真空槽1と、この真空槽1の中に配置され、負
の電圧が印加されるターゲット電極2と、このターゲッ
ト電極2に対向して配置され、処理する試料sを設置す
る試料台3とを有し、この試料台3の近傍に、ターゲッ
ト電極2に対して正の電圧を印加する電極4を配置する
と共に、前記ターゲット電極2を、イオン衝撃に対して
スパッタ率の低い金属とすることにより、その表面にて
陽イオンを反射させる電極材料としたことを特徴とする
ものである。
The ion shower sample processing apparatus according to the present invention for achieving the above object has a vacuum chamber 1 maintained in a dilute gas state, and is disposed in the vacuum chamber 1 to which a negative voltage is applied. A target electrode 2, and a sample stage 3 disposed opposite to the target electrode 2 and on which a sample s to be processed is installed, and a positive voltage is applied to the target electrode 2 near the sample stage 3. In addition to the arrangement of the electrode 4 to be applied, the target electrode 2 is made of a metal having a low sputtering rate against ion bombardment, so that an electrode material that reflects cations on the surface thereof is used. is there.

【0008】このようなイオンシャワー試料処理装置を
使用して、試料を処理するには、真空槽1内を希薄気体
状態に維持し、ターゲット電極2と正の電極4との間で
プラズマ放電を起こし、このプラズマ放電により発生し
た陽イオンを前記ターゲット電極2に反射させ、前記試
料台3上に設置した試料sに、前記ターゲット電極2で
反射した陽イオンをシャワー状に照射する。
In order to process a sample using such an ion shower sample processing apparatus, the inside of the vacuum chamber 1 is maintained in a rare gas state, and plasma discharge is caused between the target electrode 2 and the positive electrode 4. The cations generated by the plasma discharge are reflected on the target electrode 2, and the cations reflected on the target electrode 2 are radiated in a shower onto a sample s placed on the sample stage 3.

【0008】試料の表面の帯電現象は、試料表面に負の
電子が留まることにより生じる。そこで、これを正のイ
オンで中和させれば帯電は解消できることなる。ところ
が、陽イオンを試料の表面に加速して注入すると、陽イ
オンが試料の表面に衝撃を与え、表面硬度が小さな有機
物試料に対しては、表面の損傷が激しく、適用すること
ができない。
[0008] The charging phenomenon on the surface of the sample is caused by negative electrons remaining on the surface of the sample. Then, if this is neutralized with positive ions, the charging can be eliminated. However, when the cations are accelerated and injected into the surface of the sample, the cations impact the surface of the sample, and the surface of the organic sample having a small surface hardness is severely damaged, so that it cannot be applied.

【0009】これに対して、前記のような本発明による
イオンシャワーによる試料の処理手段では、プラズマ放
電により発生した陽イオンをターゲット電極2で反射さ
せ、これを中立電位の試料台3上に設置した試料sにシ
ャワー状に照射するため、試料sの表面に陽イオンの衝
撃を与えることなく同陽イオンを試料sの表面に注入す
ることができる。また、イオンを試料sの表面にシャワ
ー状に照射するため、表面に凹凸がある試料でも、いわ
ゆる陰になる部分にもイオンを回り込ませることができ
る。これにより、試料sの表面を損傷させることなく、
その表面全体を満遍なく除電することができる。
On the other hand, in the sample processing means using the ion shower according to the present invention as described above, the cations generated by the plasma discharge are reflected by the target electrode 2 and placed on the sample stage 3 at a neutral potential. Since the irradiated sample s is irradiated in the form of a shower, the same cations can be injected into the surface of the sample s without giving a positive ion impact to the surface of the sample s. In addition, since the surface of the sample s is irradiated with ions in the form of a shower, even in a sample having irregularities on the surface, the ions can be sneak into a so-called negative portion. Thereby, without damaging the surface of the sample s,
The entire surface can be neutralized.

【0010】前記の正の電極を印加する電極4は、接地
電極4であり、この接地電極4を試料台3を囲んで、そ
の周囲に配置する。さらに、試料台3を中立電位、すな
わち電位的に浮遊した状態と、正の電位を印加した状態
との何れかに択一的に切り替えるスイッチ10を備える
とよい。これにより、ターゲット電極2で反射した陽イ
オンを、試料台3の試料sにシャワー状に照射したり、
或いは陽イオンを加速して試料sの照射したり、何れか
の状態を適宜選択することができる。また、真空槽1内
を、複数2の混合気体の希薄気体雰囲気とすることがで
きれば、試料sの種類に応じて最適なイオンを適宜組み
合わせて使用することができる。
The electrode 4 to which the positive electrode is applied is a ground electrode 4, and this ground electrode 4 surrounds the sample table 3 and is arranged around it. Further, it is preferable to provide a switch 10 for selectively switching the sample stage 3 between a neutral potential, that is, a state in which the sample stage 3 is floating, and a state in which a positive potential is applied. Thereby, the cations reflected by the target electrode 2 are irradiated onto the sample s on the sample stage 3 in a shower shape,
Alternatively, the sample s may be irradiated by accelerating the cations, or any state may be appropriately selected. In addition, if the inside of the vacuum chamber 1 can be made to be a dilute gas atmosphere of a plurality of mixed gases, it is possible to use optimal ions appropriately in combination according to the type of the sample s.

【0011】[0011]

【発明の実施の形態】次に、図面を参照しながら、本発
明の実施の形態について、具体的且つ詳細に説明する。
試料sの表面の帯電現象は、試料sの表面に一次電子が
照射される等して、負の電子が留まることによって起こ
る。従って、試料sの表面の帯電現象は、試料sの表面
に溜まった電子の電荷を、正のイオンで中和すれば解消
できる。
Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
The charging phenomenon on the surface of the sample s occurs when the surface of the sample s is irradiated with primary electrons and the negative electrons stay. Therefore, the charging phenomenon on the surface of the sample s can be eliminated by neutralizing the electron charges accumulated on the surface of the sample s with positive ions.

【0012】正イオンの注入法として、数kVに加速し
たアルゴイオンを照射する方法であるが、加速したアル
ゴンイオンは、試料sの表面に対する衝撃が強く、有機
物試料等のように、表面硬度が小さな試料sには利用で
きない。また、通常のイオンスパッタ装置を利用し、試
料台3を負電位にして、プラズマ放電により発生した陽
イオンを試料sに直接照射する方法もある。しかしその
場合、試料sはイオンの衝撃を受け、損傷する。従って
やはり、有機物試料等のように、表面硬度が小さな試料
sは損傷が大きい。
[0012] The method of irradiating positive ions with argo ions accelerated to several kV is a method in which the accelerated argon ions have a strong impact on the surface of the sample s and have a surface hardness similar to that of an organic sample. Not available for small samples s. There is also a method in which the sample stage 3 is set to a negative potential using a normal ion sputtering apparatus, and the sample s is directly irradiated with positive ions generated by plasma discharge. However, in that case, the sample s is damaged by the ion bombardment. Therefore, a sample s having a small surface hardness, such as an organic sample, is also greatly damaged.

【0013】試料sのイオン照射による損傷を回避する
には、イオンの衝撃力を弱めることが必要である。それ
には、数Paから数十Paの希薄気体雰囲気におけるプ
ラズマ放電により発生した陽イオンを、試料sに直接照
射することなく、負電位に保持したターゲット電極2の
表面に当てて反射させ、この反射した陽イオンを試料台
3の上に設置した試料sに照射する。こうすることによ
り、陽イオンの飛翔距離を長くすると同時に、その飛翔
過程で雰囲気ガスと衝突する。これにより、イオンのエ
ネルギが全体として小さくなり、且つイオンの飛行方向
も様々な方向に変化する。従って、試料sの表面にはあ
らゆる方向からイオンが飛来する。しかも、このシャワ
ー状のイオンのエネルギは高範囲に分布する。このた
め、複雑な表面形状の試料sの表面に一様に陽イオンを
照射できると共に、試料sの表面に留まるイオンや試料
sの内部に浸透するイオン等、イオンが様々なレベルで
試料sにイオンが注入される。このようにして試料sの
表面から内部にわたって注入される陽イオンは、試料s
に照射される1次電子を中和するので、試料sが帯電す
ることなく、SEMの観察、あるいは微小部X線分析が
正確に行える。
In order to avoid damage to the sample s due to ion irradiation, it is necessary to weaken the ion impact force. For this purpose, positive ions generated by plasma discharge in a rare gas atmosphere of several Pa to several tens Pa are applied directly to the surface of the target electrode 2 maintained at a negative potential without directly irradiating the sample s, and reflected. The sample s placed on the sample stage 3 is irradiated with the cations thus obtained. By doing so, the flight distance of the cations is increased, and at the same time, they collide with the atmospheric gas during the flight process. As a result, the energy of the ions becomes smaller as a whole, and the flight direction of the ions also changes in various directions. Therefore, ions fly from all directions to the surface of the sample s. Moreover, the energy of the shower-like ions is distributed in a high range. For this reason, the surface of the sample s having a complicated surface shape can be uniformly irradiated with cations, and ions such as ions remaining on the surface of the sample s and ions penetrating inside the sample s are applied to the sample s at various levels. Ions are implanted. The cations implanted from the surface to the inside of the sample s in this way are
Since the primary electrons applied to the sample are neutralized, observation of the SEM or X-ray analysis of a minute portion can be accurately performed without charging the sample s.

【0014】このようなイオンシャワーによる試料処理
装置に使用されるターゲット電極2としては、イオン衝
撃でスパッタされない金属、例えばFe、Cr、Ni、
Ta、Mo、Al、或いはこれらの合金を使用する。放
電電圧は、試料sの種類によって異なる。例えば、生物
試料のような有機物試料は、200Vから800V、無
機化合物等で硬質な試料sは800V以上1500V程
度とする。
As the target electrode 2 used in the sample processing apparatus using such an ion shower, a metal that is not sputtered by ion bombardment, such as Fe, Cr, Ni,
Ta, Mo, Al, or an alloy thereof is used. The discharge voltage differs depending on the type of the sample s. For example, an organic sample such as a biological sample is set to 200 V to 800 V, and a hard sample s made of an inorganic compound or the like is set to 800 V to 1500 V.

【0015】プラズマ放電電流は、その最大値をターゲ
ット電極2の面積によって決める。単位面積当りの電流
値が大きいとターゲット電極2の表面の温度上昇が激し
く、ターゲット電極2から試料sに照射される赤外線に
よって試料sが損傷するおそれがある。このため、ター
ゲット電極2の表面での電流密度の限界を0.5mA/
cm2 とすることが望ましい。或いは、大電流密度でイ
オン照射を行う場合は、ターゲット電極2を冷却し、赤
外線の放射を抑えることが望ましい。
The maximum value of the plasma discharge current is determined by the area of the target electrode 2. If the current value per unit area is large, the temperature of the surface of the target electrode 2 rises sharply, and the sample s may be damaged by infrared rays emitted from the target electrode 2 to the sample s. Therefore, the limit of the current density on the surface of the target electrode 2 is set to 0.5 mA /
cm 2 is desirable. Alternatively, when performing ion irradiation with a large current density, it is desirable to cool the target electrode 2 and suppress the emission of infrared rays.

【0016】イオン照射量は試料sの大きさ、形状によ
って決める。硬質資料においては放電電流I×時間T=
50(mA・min)を一回の照射の限界とする。希薄
気体としての雰囲気ガスは、He、N2 、Arあるいは
それらの混合ガス(空気を含む)から選択する。生物細
胞など破損し易い試料にはHe、或いはHeとN2 の混
合気体。岩石など無機化合物にはAr、或いはArとN
2 の混合気体を雰囲気ガスとする。一般的には空気の希
薄状態で行なわれる。
The amount of ion irradiation is determined by the size and shape of the sample s. For hard materials, the discharge current I × time T =
50 (mA · min) is the limit of one irradiation. The atmosphere gas as the lean gas is selected from He, N 2 , Ar, or a mixed gas thereof (including air). He or a mixed gas of He and N 2 for samples that are easily damaged, such as biological cells. Ar or Ar and N are used for inorganic compounds such as rocks.
The mixed gas of 2 is used as atmospheric gas. Generally, it is carried out in a lean state of air.

【0017】以上述べた原理作用と実験結果を元に装置
を構成する。この装置を例を図1に示す。1Pa以下の
圧力雰囲気を保持できる真空槽1内に、イオン衝撃によ
ってスパッタされない金属で作られたターゲット電極2
を真空槽1に対して絶縁して設け、直流電源8によって
このターゲット電極2に負電圧を印加し、負電位とす
る。図1において、符合9は電圧調整器、符合Vは電源
8の電圧を測定する電位計、符合mAは、電源8の電流
を測定する電流計である。ターゲット電極2は、これに
対して絶縁された静電電極5によって囲み、放電によっ
て生じるプラズマイオンがターゲット電極2の表面を効
率よく衝撃するようにする。
An apparatus is constructed based on the above-described principle operation and experimental results. An example of this device is shown in FIG. A target electrode 2 made of a metal not sputtered by ion bombardment in a vacuum chamber 1 capable of holding a pressure atmosphere of 1 Pa or less.
Is provided insulated from the vacuum chamber 1, and a negative voltage is applied to the target electrode 2 by the DC power supply 8 to make it negative potential. In FIG. 1, reference numeral 9 denotes a voltage regulator, reference numeral V denotes an electrometer for measuring the voltage of the power supply 8, and reference numeral mA denotes an ammeter for measuring the current of the power supply 8. The target electrode 2 is surrounded by an electrostatic electrode 5 insulated from the target electrode 2 so that plasma ions generated by discharge bombard the surface of the target electrode 2 efficiently.

【0018】このターゲット電極2と対向して、真空槽
1と電気的に絶縁された試料台3を設置する。さらに、
試料台3の周囲に接地電極4を設け、この接地電極4を
前記ターゲット電極2に対して正電位におく。具体的に
は、真空槽1の下部プレートを介して接地する。試料台
3とアースとは、スイッチ10及び真空槽を介して接続
及び切断することができるようにしてある。すなわち、
図示のようにスイッチ10を切ったとき、試料台3はア
ースから切り離されて、電位的に浮遊し、ターゲット電
極2と接地電極4の双方に対して中立した電位にある。
他方、スイッチ10を閉じると、試料台3は接地され、
接地電極4と同電位となる。このようなスイッチ10を
設けることにより、後述するように、ターゲット電極2
で反射した陽イオンを試料台3上の試料sに入射させる
エネルギを適宜変えることができる。
A sample table 3 is placed opposite to the target electrode 2 and electrically insulated from the vacuum chamber 1. further,
A ground electrode 4 is provided around the sample stage 3, and the ground electrode 4 is set at a positive potential with respect to the target electrode 2. Specifically, it is grounded via the lower plate of the vacuum chamber 1. The sample stage 3 and the ground can be connected and disconnected via the switch 10 and the vacuum chamber. That is,
As shown, when the switch 10 is turned off, the sample stage 3 is disconnected from the ground, floats in potential, and is at a potential neutral to both the target electrode 2 and the ground electrode 4.
On the other hand, when the switch 10 is closed, the sample stage 3 is grounded,
It has the same potential as the ground electrode 4. By providing such a switch 10, as described later, the target electrode 2
It is possible to appropriately change the energy at which the cations reflected by the sample enter the sample s on the sample stage 3.

【0019】真空槽1内は真空ポンプ11によって排気
すると共に、雰囲気ガス注入装置6より真空槽1内に前
述のような希薄ガスを注入し、真空槽1内を3Paない
し100Pa程度の圧力雰囲気を保つ。試料台2にSE
Mで観察するための試料sを並べ、真空排気を行った
後、真空槽1内に前述のような試料に対応したガスを注
入し、真空槽1内を例えば10Pa付近の希薄ガス雰囲
気に保持する。そして、ターゲット電極を負、接地電極
を正の直流電圧を印加し、放電を開始する。
The inside of the vacuum chamber 1 is evacuated by a vacuum pump 11 and the above-mentioned diluent gas is injected into the vacuum chamber 1 from an atmosphere gas injection device 6 to evacuate the vacuum chamber 1 to a pressure atmosphere of about 3 Pa to 100 Pa. keep. SE on sample stage 2
After arranging the samples s for observation in M and evacuating, a gas corresponding to the above-described sample is injected into the vacuum chamber 1 and the inside of the vacuum chamber 1 is maintained in a rare gas atmosphere of, for example, about 10 Pa. I do. Then, a negative DC voltage is applied to the target electrode and a positive DC voltage is applied to the ground electrode to start discharging.

【0020】この放電によるプラズマ中で発生した陽イ
オンは、ターゲット電極2の表面に当たって反射し、さ
らに希薄ガス雰囲気中のガス分子と衝突すると共に、イ
オン同志で反発し合い、試料台3上の試料sにあらゆる
方向からあらゆるエネルギーで飛来する。いわゆる、陽
イオンがシャワー状に試料sに照射される。このとき、
必要時間放電を持続させることにより試料sの表面から
試料内部へイオンが浸透する。また、イオンの浸透し難
い硬質試料の場合は、前記のスイッチ10と閉じて、試
料台3を接地し、陽イオンに或る程度のエネルギを与え
ることにより、試料sの内部へのイオンの浸透が加速さ
れる。
The cations generated in the plasma by the discharge strike the surface of the target electrode 2 and are reflected, collide with gas molecules in a dilute gas atmosphere, and repel each other with ions. Flying from any direction to any energy. So-called cations are irradiated to the sample s in a shower shape. At this time,
The ions permeate from the surface of the sample s to the inside of the sample by maintaining the discharge for the required time. In the case of a hard sample in which ions do not easily penetrate, the switch is closed with the switch 10, the sample stage 3 is grounded, and a certain amount of energy is applied to the cations, so that the ions penetrate into the sample s. Is accelerated.

【0021】放電電流とイオン照射時間は試料の大きさ
と種類によって異なるが、厚さ1mm程度の有機質薄片
試料の場合、雰囲気ガスを空気とし、放電電圧V=60
0V、放電電流I=3〜5mA、時間T=10minの
イオンシャワー照射で20kV加速電圧のSEM観察に
十分耐えられる。セラミック等の無気質試料の場合は雰
囲気ガスをArとし、V=1000V、I=10mA、
T=5minのイオンシャワーで25kVでのSEM観
察、及び微小部X線分析が可能である。
Although the discharge current and the ion irradiation time vary depending on the size and type of the sample, in the case of an organic thin sample having a thickness of about 1 mm, the atmosphere gas is air and the discharge voltage V = 60.
The ion shower irradiation at 0 V, discharge current I = 3 to 5 mA, and time T = 10 min can sufficiently withstand SEM observation at an acceleration voltage of 20 kV. In the case of a gaseous sample such as a ceramic, the atmosphere gas is Ar, V = 1000 V, I = 10 mA,
SEM observation at 25 kV with a T = 5 min ion shower and microscopic X-ray analysis are possible.

【0022】このようなイオンシャワー処理を施された
試料sは、その表面付近から内部にわたり陽イオンが存
在し、正電位の状態を保つ。これにより、高加速電圧の
SEM観察、あるいは微小部X線分析に対し、電子の電
荷を中和し、試料sの帯電を防止する。
The sample s which has been subjected to such an ion shower treatment contains cations from near the surface to the inside thereof, and maintains a positive potential state. This neutralizes the electron charge for SEM observation at a high accelerating voltage or X-ray microscopic analysis, thereby preventing the sample s from being charged.

【0023】[0023]

【発明の効果】以上説明したとおり、本発明のイオンシ
ャワー試料処理装置と方法では、単に試料表面へ陽イオ
ンをシャワー状に照射することができ、金属の蒸着を行
うことなく25Kv程度の高電圧加速SEMでも帯電現
象を起こさずに観察が可能になる。従来、高分解能観察
の場合は試料表面に2〜3nmの薄い白金蒸着膜を形成
させて帯電を防止していたが、観察時の電子線照射量、
あるいは観察時間によって導電性能が低下し、観察条件
に限界があった。また、再度金属蒸着を行うことは蒸着
層が厚くなり、高分解能観察を不可能にした。特に凹凸
の甚だしい試料に於ては陰の部分には金属粒子が蒸着さ
れず、炭素などの補助蒸着を必要とし、これが微細構造
の観察を不可能にしていた。
As described above, according to the ion shower sample processing apparatus and method of the present invention, it is possible to simply irradiate the sample surface with cations in the form of a shower, and a high voltage of about 25 Kv can be obtained without performing metal deposition. Observation is possible without causing a charging phenomenon even with an accelerated SEM. Conventionally, in the case of high-resolution observation, a thin platinum vapor-deposited film of 2 to 3 nm was formed on the sample surface to prevent charging, but the amount of electron beam irradiation during observation,
Alternatively, the conductive performance was reduced by the observation time, and the observation conditions were limited. Further, performing the metal vapor deposition again thickens the vapor deposited layer, making high-resolution observation impossible. In particular, in the case of a sample having severe irregularities, metal particles were not deposited on the shadow area, and an auxiliary deposition of carbon or the like was required, which made observation of a fine structure impossible.

【0024】本発明のイオンシャワー試料処理装置と方
法では、試料表面を直接観察するので、真の表面構造が
観察できるばかりでなく、表面に凹凸のある試料でも、
イオンの進入構造によって穴の内部まで観察が可能であ
る。また、長時間の観察、あるいは保管で帯電現象が発
生しても再度のイオンシャワーで繰り返し観察が可能で
あるから、重要な試料のSEM観察に利用して効果極め
て大である。さらに、SEM観察と同時に観察部分のX
線分析が行えるので、形態と成分の比較研究が用意とな
り、考古学的出土品の鑑定、犯罪走査等にも有効であ
る。
In the ion shower sample processing apparatus and method of the present invention, since the surface of the sample is directly observed, not only the true surface structure can be observed, but also the sample having an uneven surface.
It is possible to observe the inside of the hole by the structure of ion penetration. Further, even if a charging phenomenon occurs during long-term observation or storage, repeated observations can be made by using the ion shower again. Therefore, the effect is extremely large when used for SEM observation of an important sample. Furthermore, the X of the observed part is simultaneously observed with the SEM observation.
Since a line analysis can be performed, comparative studies of morphology and components are ready, and it is also effective for archaeological excavations, crime scanning, etc.

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

【図1】本発明によりイオンシャワー試料処理装置の例
を示す真空槽1を断面した概略側面全体構成図である。
FIG. 1 is a schematic overall side view of a vacuum chamber 1 showing an example of an ion shower sample processing apparatus according to the present invention.

【符号の説明】[Explanation of symbols]

1 真空槽 2 ターゲット電極 3 試料台 4 接地電極 6 雰囲気ガス注入装置 7 雰囲気圧力測定機 8 電源 11 排気装置 s 試料 DESCRIPTION OF SYMBOLS 1 Vacuum tank 2 Target electrode 3 Sample stand 4 Ground electrode 6 Atmospheric gas injection device 7 Atmospheric pressure measuring device 8 Power supply 11 Exhaust device s Sample

───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.6 識別記号 FI H01J 37/20 H01J 37/34 37/34 G01N 1/28 Z ──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. 6 Identification code FI H01J 37/20 H01J 37/34 37/34 G01N 1/28 Z

Claims (6)

【特許請求の範囲】[Claims] 【請求項1】 希薄気体状態に維持される真空槽(1)
と、この真空槽(1)の中に配置され、負の電圧が印加
されるターゲット電極(2)と、このターゲット電極
(2)に対向して配置され、処理する試料(s)を設置
する試料台(3)とを有し、前記試料台(3)の近傍に
ターゲット電極(2)に対して正の電圧の電極(4)を
配置し、ターゲット電極(2)を、イオン衝撃に対して
スパッタ率の低い金属とすることにより、その表面にて
陽イオンを反射させる電極材料としたプラズマイオンシ
ャワー試料処理装置。
A vacuum chamber maintained in a lean gas state (1)
And a target electrode (2) arranged in the vacuum chamber (1) to which a negative voltage is applied, and a sample (s) arranged to face the target electrode (2) and processed. A sample stage (3), and an electrode (4) having a positive voltage with respect to the target electrode (2) is arranged near the sample stage (3), and the target electrode (2) is subjected to ion bombardment. A plasma ion shower sample processing apparatus using an electrode material that reflects cations on the surface by using a metal having a low sputtering rate.
【請求項2】 正の電極の電極(4)が接地電極(4)
であることを特徴とする請求項1に記載のプラズマイオ
ンシャワー試料処理装置。
2. The electrode (4) of a positive electrode is a ground electrode (4).
The plasma ion shower sample processing apparatus according to claim 1, wherein:
【請求項3】 試料台(3)を、電位的に浮遊した状態
と正の電位との何れかに択一的に切り替えるスイッチ
(10)を備えることを特徴とする請求項1または2に
記載のプラズマイオンシャワー試料処理装置。
3. A switch according to claim 1, further comprising a switch for selectively switching the sample stage between a potential floating state and a positive potential. Plasma ion shower sample processing equipment.
【請求項4】 試料台(3)を囲んで、その周囲に正の
電極の電極(4)を配置したことを特徴とする請求項1
〜3の何れかに記載のプラズマイオンシャワー試料処理
装置。
4. A positive electrode (4) surrounding the sample stage (3) and surrounding the sample stage (3).
4. The plasma ion shower sample processing apparatus according to any one of claims 1 to 3.
【請求項5】 真空槽(1)内を希薄気体状態に維持
し、この真空槽(1)の中に配置され、負の電圧が印加
されるターゲット電極(2)と、このターゲット電極
(2)に対向して配置され、同ターゲット電極(2)に
対して正の電圧を印加した電極(4)との間でプラズマ
放電を起こし、このプラズマ放電により発生した陽イオ
ンを前記ターゲット電極(2)に反射させ、このターゲ
ット電極(2)と対向して配置した中立電位の試料台
(3)上に設置した試料(s)に、前記ターゲット電極
(2)で反射した陽イオンをシャワー状に照射すること
を特徴とするプラズマイオンシャワー試料処理方法。
5. A target electrode (2) which is disposed in the vacuum chamber (1) and is provided with a negative voltage, while maintaining the inside of the vacuum chamber (1) in a lean gas state. ), A plasma discharge is caused between the target electrode (2) and an electrode (4) to which a positive voltage is applied to the target electrode (2), and cations generated by the plasma discharge are generated by the target electrode (2). ), And the cations reflected by the target electrode (2) are showered on a sample (s) placed on a neutral-potential sample stage (3) placed opposite to the target electrode (2). A method for treating a plasma ion shower sample, comprising irradiating the sample.
【請求項6】 真空槽(1)内の希薄気体を2種類以上
の混合気体雰囲気に保持することを特徴とする請求項5
に記載のプラズマイオンシャワー試料処理方法。
6. The method according to claim 5, wherein the rare gas in the vacuum chamber is maintained in a mixed gas atmosphere of two or more kinds.
4. The plasma ion shower sample processing method according to 1.
JP9189284A 1997-06-30 1997-06-30 Plasma ion shower sample treating device and its method Pending JPH1125894A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP9189284A JPH1125894A (en) 1997-06-30 1997-06-30 Plasma ion shower sample treating device and its method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9189284A JPH1125894A (en) 1997-06-30 1997-06-30 Plasma ion shower sample treating device and its method

Publications (1)

Publication Number Publication Date
JPH1125894A true JPH1125894A (en) 1999-01-29

Family

ID=16238754

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
JP (1) JPH1125894A (en)

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