JPH10241616A - Electrostatic lens - Google Patents
Electrostatic lensInfo
- Publication number
- JPH10241616A JPH10241616A JP9041895A JP4189597A JPH10241616A JP H10241616 A JPH10241616 A JP H10241616A JP 9041895 A JP9041895 A JP 9041895A JP 4189597 A JP4189597 A JP 4189597A JP H10241616 A JPH10241616 A JP H10241616A
- Authority
- JP
- Japan
- Prior art keywords
- electrostatic lens
- electrode
- lens
- charged particle
- acceleration
- 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.)
- Granted
Links
- 239000002245 particle Substances 0.000 claims abstract description 36
- 230000001133 acceleration Effects 0.000 claims description 48
- 238000010884 ion-beam technique Methods 0.000 abstract description 47
- 230000004075 alteration Effects 0.000 abstract description 24
- 150000002500 ions Chemical class 0.000 abstract description 14
- 238000010586 diagram Methods 0.000 description 4
- 230000005684 electric field Effects 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、荷電粒子線の集束
性を制御する静電レンズに関し、特に色収差の小さな静
電レンズに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic lens for controlling the convergence of a charged particle beam, and more particularly to an electrostatic lens having small chromatic aberration.
【０００２】[0002]
【従来の技術】イオンや電子などの荷電粒子線の制御に
は電子レンズが使用される。電子レンズには、磁界の作
用で荷電粒子線を集束する磁界レンズと、電界の作用で
集束する静電レンズとがあり、イオンビームの制御には
静電レンズが使われる。静電レンズは磁界レンズに比べ
て色収差が大きく、静電レンズを用いてイオンビームを
細く絞る限界は、通常、その静電レンズの色収差の大き
さに依存する。2. Description of the Related Art An electron lens is used for controlling charged particle beams such as ions and electrons. Electron lenses include a magnetic lens that focuses a charged particle beam by the action of a magnetic field and an electrostatic lens that focuses by the action of an electric field. An electrostatic lens is used to control an ion beam. An electrostatic lens has larger chromatic aberration than a magnetic lens, and the limit of narrowing an ion beam using an electrostatic lens usually depends on the magnitude of chromatic aberration of the electrostatic lens.
【０００３】ビームを集束する目的の静電レンズには、
通常、入口と出口の電位が等しい静電レンズが使われ
る。図４は、正電荷を有するイオンビームの集束に用い
られる従来の静電レンズの構造を示す概略図である。こ
の静電レンズ４は、入射側電極５、出射側電極７、及び
それらの中間に置かれた中間電極６の３個の電極で構成
されている。入射側電極５と出射側電極７はイオンビー
ム照射試料（ターゲット）９と同じ電位に保たれる。An electrostatic lens for focusing a beam includes:
Usually, an electrostatic lens having the same potential at the entrance and the exit is used. FIG. 4 is a schematic view showing a structure of a conventional electrostatic lens used for focusing an ion beam having a positive charge. The electrostatic lens 4 is composed of three electrodes: an entrance electrode 5, an exit electrode 7, and an intermediate electrode 6 placed therebetween. The entrance electrode 5 and the exit electrode 7 are kept at the same potential as the ion beam irradiation sample (target) 9.
【０００４】静電レンズの特徴として、中間電極６の電
位を、入・出射側電極５，７の電位より高くしても、低
くしてもイオンビームを集束することができる。前者の
集束は、静電レンズの中でイオンビームをレンズ入射前
より更に加速して集束させるので加速モードの集束と呼
ばれ、後者の集束は静電レンズの中でイオンビームをレ
ンズ入射前より減速して集束させるので減速モードの集
束と呼ばれる。As a feature of the electrostatic lens, the ion beam can be focused regardless of whether the potential of the intermediate electrode 6 is higher or lower than the potential of the input / output electrodes 5 and 7. The former focusing is referred to as acceleration mode focusing because the ion beam is further accelerated and focused in the electrostatic lens before entering the lens, and the latter focusing is used to focus the ion beam in the electrostatic lens from before entering the lens. This is called focusing in a deceleration mode because the focusing is performed at a reduced speed.
【０００５】最初に、図４の静電レンズを減速モードで
動作させる例について説明する。イオンビーム加速用電
源３によって例えば＋３０ｋＶの電圧が印可されたイオ
ン源１より引出されたイオンビーム２は、接地電位にさ
れた加速電極２５との間で３０ｋｅＶのエネルギーに加
速され、静電レンズ４に入る。静電レンズ４の入射側電
極５及び出射側電極７は接地され、中間電極６はレンズ
電源８に接続されている。電極５，６，７は直径３ｍｍ
の中心孔を有し、それぞれ２ｍｍずつ離して配置されて
いる。レンズ電源８により中間電極６に約＋２０ｋＶの
電圧を印可すると、静電レンズ４に入射したイオンビー
ムは中間電極６により減速され、出射側電極７で再び３
０ｋｅＶのエネルギーに戻されて静電レンズ４を出る。
この時、静電レンズ４は焦点距離１５ｍｍの凸レンズと
して作用し、イオンビームを静電レンズ４から約１２ｍ
ｍ離れたターゲット９上に集束する。First, an example of operating the electrostatic lens of FIG. 4 in a deceleration mode will be described. The ion beam 2 extracted from the ion source 1 to which a voltage of, for example, +30 kV is applied by the ion beam acceleration power supply 3 is accelerated to an energy of 30 keV between the ground electrode and the acceleration electrode 25, and the electrostatic lens 4 is charged. to go into. The entrance electrode 5 and the exit electrode 7 of the electrostatic lens 4 are grounded, and the intermediate electrode 6 is connected to a lens power supply 8. Electrodes 5, 6, 7 are 3mm in diameter
, And are arranged at a distance of 2 mm from each other. When a voltage of about +20 kV is applied to the intermediate electrode 6 by the lens power supply 8, the ion beam incident on the electrostatic lens 4 is decelerated by the intermediate electrode 6, and the ion beam 3
The energy is returned to 0 keV and exits the electrostatic lens 4.
At this time, the electrostatic lens 4 acts as a convex lens with a focal length of 15 mm, and the ion beam is
Focus on a target 9 m away.
【０００６】もし静電レンズ４に収差がなければ、イオ
ンビームはターゲット９上の一点Ｐを照射し、極めて細
いビームが形成される。実際には、静電レンズ４の色収
差のために、イオンビームは図のように広がった状態で
ターゲット９を照射する。色収差によるイオンビームの
広がりｄは、静電レンズ４の色収差係数Ｃcに比例す
る。イオンビームはなるべく細く絞りたいので、色収差
係数Ｃcが小さい静電レンズほど優れたレンズである。
図４に示した減速モード集束の条件では、色収差係数Ｃ
cは約５０ｍｍである。If the electrostatic lens 4 has no aberration, the ion beam irradiates one point P on the target 9 and an extremely thin beam is formed. Actually, due to the chromatic aberration of the electrostatic lens 4, the ion beam irradiates the target 9 in a spread state as shown in the figure. The spread d of the ion beam due to chromatic aberration is proportional to the chromatic aberration coefficient Cc of the electrostatic lens 4. Since it is desired to stop the ion beam as thin as possible, an electrostatic lens having a smaller chromatic aberration coefficient Cc is a better lens.
Under the deceleration mode focusing condition shown in FIG.
c is about 50 mm.
【０００７】[0007]
【発明が解決しようとする課題】ところで、加速モード
での色収差係数は、減速モードでの色収差係数の約１／
３程度に小さいため、色収差を小さくするには従来の静
電レンズを加速モードで動作させて使うのが有利であ
る。しかし、高エネルギーの荷電粒子線に対して静電レ
ンズを加速モードで動作させて集束しようとすると、技
術的及び経済的に困難な問題に遭遇する。例えば、３０
ｋｅＶのエネルギーに加速したイオンビームを図１のレ
ンズで焦点距離１５ｍｍで集束しようとするとき、加速
モードで集束するには中間電極６にレンズ電源８から約
−５０ｋＶの高電圧を印加する必要がある。この時の色
収差係数Ｃcは２０ｍｍまで小さくなる。ところが静電
レンズ４を構成する電極５，６，７間の間隔は２ｍｍで
あるため、中間電極６にこのような高電圧を印加する
と、電極５，６の間及び電極６，７の間には２５ｋＶ／
ｍｍもの強い電界が作用し、放電によりレンズが破壊し
てしまう。放電を生じさせないための電界強度の許容値
は、真空中でせいぜい１０ｋＶ／ｍｍである。By the way, the chromatic aberration coefficient in the acceleration mode is about 1 / the value of the chromatic aberration coefficient in the deceleration mode.
Since it is as small as about 3, it is advantageous to use a conventional electrostatic lens operated in an acceleration mode to reduce chromatic aberration. However, when the electrostatic lens is operated in the acceleration mode to focus on the high energy charged particle beam, technically and economically difficult problems are encountered. For example, 30
When the ion beam accelerated to keV energy is focused by the lens of FIG. 1 at a focal length of 15 mm, it is necessary to apply a high voltage of about −50 kV from the lens power source 8 to the intermediate electrode 6 to focus in the acceleration mode. is there. At this time, the chromatic aberration coefficient Cc is reduced to 20 mm. However, since the distance between the electrodes 5, 6, and 7 constituting the electrostatic lens 4 is 2 mm, when such a high voltage is applied to the intermediate electrode 6, between the electrodes 5, 6 and between the electrodes 6, 7 Is 25 kV /
A strong electric field as large as mm causes the lens to break due to discharge. The allowable value of the electric field strength for preventing the discharge is at most 10 kV / mm in a vacuum.
【０００８】そこで、この静電レンズを加速モードで動
作させるためには、中間電極６と入／出射側電極５，７
との間隔を５ｍｍに増し、かつ電圧供給ケーブルも５０
ｋＶの高電圧に対して絶縁破壊を起こさないように注意
を払う必要がある。さらに、レンズ電源８も、２０ｋＶ
出力用電源と５０ｋＶ出力用電源とでは経済性の点でも
大幅に異なってくる。このような事情により、高エネル
ギーの荷電粒子線に対しては、静電レンズは色収差は大
きくても、低い電圧印加で集束できる減速モードでの集
束を行うことが多かった。In order to operate this electrostatic lens in the acceleration mode, the intermediate electrode 6 and the input / output side electrodes 5 and 7 are required.
And the voltage supply cable to 50 mm
Care must be taken to avoid dielectric breakdown for high voltages of kV. Further, the lens power supply 8 is also 20 kV
The power supply for output and the power supply for 50 kV output are significantly different in terms of economy. Under such circumstances, an electrostatic lens often performs focusing in a deceleration mode in which a high-energy charged particle beam can be focused by applying a low voltage even if the chromatic aberration is large.
【０００９】本発明は、このような従来技術の問題点に
鑑みてなされたもので、高エネルギーの荷電粒子線に対
しても、従来の加速モードでの印加電圧に比べると低い
印加電圧で集束でき、かつ、従来の減速モードでの集束
に比べると小さい色収差で集束できる静電レンズを提供
することを目的とする。The present invention has been made in view of such problems of the prior art, and focuses a charged particle beam of high energy at a lower applied voltage than the applied voltage in the conventional acceleration mode. It is an object of the present invention to provide an electrostatic lens which can be focused and has a small chromatic aberration as compared with focusing in a conventional deceleration mode.
【００１０】[0010]
【課題を解決するための手段】本発明においては、静電
レンズの内部に複数個の電極を設け、静電レンズの内部
で荷電粒子の加速と減速とを行うことにより前記目的を
達成する。すなわち、本発明の静電レンズは、静電レン
ズの内部に、入射した荷電粒子線を加速する加速用電極
と減速する減速用電極とを設けたことを特徴とする。In the present invention, the above object is achieved by providing a plurality of electrodes inside an electrostatic lens and accelerating and decelerating charged particles inside the electrostatic lens. That is, the electrostatic lens of the present invention is characterized in that an acceleration electrode for accelerating an incident charged particle beam and a deceleration electrode for decelerating the charged particle beam are provided inside the electrostatic lens.
【００１１】前記加速用電極と減速用電極は、レンズに
入射した荷電粒子線が、まず減速され、次いで加速され
るように配置してもよいし、レンズに入射した荷電粒子
線が、まず加速され、次いで減速されるように配置して
もよい。もちろん、加速と減速を交互に複数回繰り返す
ようにしてもよい。入射側電極と出射側電極が同電位あ
るいは接地されている静電レンズの場合、静電レンズ内
の加速用電極は荷電粒子線を静電レンズ入射前のエネル
ギーより高いエネルギーに加速し、減速用電極は荷電粒
子線を静電レンズ入射前のエネルギーより低いエネルギ
ーに減速する。The acceleration electrode and the deceleration electrode may be arranged so that the charged particle beam incident on the lens is first decelerated and then accelerated, or the charged particle beam incident on the lens is first accelerated. And then arranged to be decelerated. Of course, the acceleration and the deceleration may be alternately repeated a plurality of times. In the case of an electrostatic lens in which the input side electrode and the output side electrode are at the same potential or grounded, the acceleration electrode in the electrostatic lens accelerates the charged particle beam to energy higher than the energy before entering the electrostatic lens and decelerates it. The electrode decelerates the charged particle beam to an energy lower than the energy before the incidence of the electrostatic lens.
【００１２】減速用電極に、荷電粒子線源から発生した
荷電粒子線を所定のエネルギーに加速する荷電粒子線加
速用電源の電圧を分圧して供給するようにして、静電レ
ンズの減速用電極電源を荷電粒子加速用電源で兼用して
もよい。A voltage of a charged particle beam accelerating power source for accelerating a charged particle beam generated from a charged particle beam source to a predetermined energy is supplied to the decelerating electrode, so that the decelerating electrode of the electrostatic lens is supplied. The power supply may be shared by a charged particle acceleration power supply.
【００１３】本発明の静電レンズは、その像面を荷電粒
子線照射用試料面に対応させた荷電粒子線集束用対物レ
ンズとして荷電粒子線集束装置に使用することができ、
また、その物面を荷電粒子線像投影用試料面に対応させ
た荷電粒子線像投影用対物レンズとして荷電粒子線投影
装置に使用することができる。The electrostatic lens of the present invention can be used in a charged particle beam focusing device as a charged particle beam focusing objective lens whose image plane corresponds to the charged particle beam irradiation sample surface,
Further, the charged particle beam projection apparatus can be used as a charged particle beam image projection objective lens whose object surface corresponds to the charged particle beam image projection sample surface.
【００１４】[0014]
【発明の実施の形態】以下、図面を参照して本発明の実
施の形態を説明する。以下の図において、従来例を示す
図４と同一の機能部分には図４と同一の符号を付してそ
の詳細な説明を省略する。Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same functional portions as in FIG. 4 showing the conventional example are denoted by the same reference numerals as in FIG. 4 and detailed description thereof will be omitted.
【００１５】図１は、本発明による静電レンズの一例を
説明する概略図である。この静電レンズ２４は、静電レ
ンズ２４に入射したイオンビーム２を静電レンズ２４の
中で加速する２個の加速用電極（加速用第１電極１０、
加速用第２電極１１）と、減速する減速用電極１２とを
含む合計５個の電極を備える。イオン源１にはイオンビ
ーム加速用電源３から＋３０ｋＶの電圧が印可され、イ
オンビーム加速電極２５、静電レンズ２４の入射側電極
５及び出射側電極７は接地されている。静電レンズ２４
の入射側電極５と加速用第１電極１０の間隔は３ｍｍ、
加速用第１電極１０及び加速用第２電極１１と減速用電
極１２の間隔はそれぞれ５ｍｍ、加速用第２電極１１と
出射側電極７の間隔は３ｍｍとした。FIG. 1 is a schematic diagram illustrating an example of an electrostatic lens according to the present invention. The electrostatic lens 24 has two accelerating electrodes (first accelerating electrodes 10 and 10) for accelerating the ion beam 2 incident on the electrostatic lens 24 in the electrostatic lens 24.
A total of five electrodes including a second electrode for acceleration 11) and a deceleration electrode 12 for deceleration are provided. A voltage of +30 kV is applied from the ion beam acceleration power supply 3 to the ion source 1, and the ion beam acceleration electrode 25, the entrance electrode 5 and the exit electrode 7 of the electrostatic lens 24 are grounded. Electrostatic lens 24
The distance between the incident side electrode 5 and the first acceleration electrode 10 is 3 mm,
The distance between the first acceleration electrode 10, the second acceleration electrode 11, and the deceleration electrode 12 was 5 mm, and the distance between the second acceleration electrode 11 and the emission-side electrode 7 was 3 mm.
【００１６】加速用第１電極１０及び加速用第２電極１
１に加速用レンズ電源１３から−３０ｋＶの電圧を印加
し、減速用電極１２に減速用レンズ電源１４から＋２
０．２ｋＶの電圧を印加すると、イオンビームは静電レ
ンズ２４から約７ｍｍ離れたターゲット９の上に集束す
る。このとき、静電レンズ２４の色収差係数Ｃcは２
３．３ｍｍであり、図４で説明した従来のの静電レンズ
の色収差係数Ｃc６０ｍｍの約１／２．５である。First acceleration electrode 10 and second acceleration electrode 1
1 is applied with a voltage of −30 kV from the acceleration lens power supply 13, and +2 is applied to the deceleration electrode 12 from the deceleration lens power supply 14
When a voltage of 0.2 kV is applied, the ion beam is focused on the target 9 about 7 mm away from the electrostatic lens 24. At this time, the chromatic aberration coefficient Cc of the electrostatic lens 24 is 2
It is 3.3 mm, which is about 1 / 2.5 of the chromatic aberration coefficient Cc of the conventional electrostatic lens described in FIG.
【００１７】静電レンズの中で加速と減速とを行うこと
により色収差係数Ｃcが小さくなる理由は、静電レンズ
内部でのレンズ軸に沿った電位の変化を考えると理解す
ることができる。すなわち、静電レンズの焦点距離を
ｆ、静電レンズの物面側電位をΦO 、静電レンズの像面
側電位をΦI 、レンズ作用最大位置での軸上電位をΦm
とするとき、色収差係数Ｃcは薄肉レンズの近似で次の
〔数１〕の関係を有し（裏克己著「電子・イオンビーム
光学」１９９４年、共立出版株式会社、第７２頁）、Ｃ
c／ｆはレンズ作用最大位置での電位Φm が高いほど小
さい。The reason why the chromatic aberration coefficient Cc is reduced by performing acceleration and deceleration in the electrostatic lens can be understood by considering a change in potential along the lens axis inside the electrostatic lens. That is, the focal length of the electrostatic lens is f, the object-surface potential of the electrostatic lens is Φ O , the image-surface potential of the electrostatic lens is Φ I , and the on-axis potential at the lens action maximum position is Φ m
, The chromatic aberration coefficient Cc has the following relationship (Equation 1) in the approximation of a thin lens (Katsumi Ura, “Electron / Ion Beam Optics”, 1994, Kyoritsu Shuppan Co., Ltd., p. 72):
c / f is smaller as the potential Φ m at the lens action maximum position is higher.
【００１８】[0018]
【数１】Ｃc／ｆ＝２（ΦO ・ΦI ）1/4 ／Φm 1/2 減速モード動作においてレンズ作用が最大となる位置
は、減速用電極の部分である。そこで、もし、この部分
の左右（前後）の領域でのイオンビームのエネルギーを
高くすると、必要な強さのレンズ作用にはより高い電
位、すなわち高電位のΦm を必要とすることとなり、そ
の結果、小さいＣc／ｆのレンズ作用をするようにな
る。図１では、減速用電極１２の前後に加速用電極１
０，１１を設けて減速用電極部の電位が高い状態でイオ
ンビームを集束するように構成されている。## EQU1 ## The position where the lens action is maximized in the deceleration mode operation is Cc / f = 2 (Φ O Φ I ) 1/4 / Φ m 1/2 . Therefore, if the energy of the ion beam in the left and right (front and back) regions of this portion is increased, a higher potential, that is, a higher potential Φ m is required for the lens action of the required intensity, As a result, a small Cc / f lens action is achieved. In FIG. 1, the acceleration electrode 1 is located before and after the deceleration electrode 12.
0 and 11 are provided to focus the ion beam in a state where the potential of the deceleration electrode portion is high.
【００１９】図２は、本発明による他の静電レンズを集
束イオンビーム加工・観察装置に応用した例を示す概略
図である。イオン源１より発射されたイオンビーム２
は、コンデンサーレンズ１８及び偏向器１５を通過し
て、静電レンズ３４に入る。この例に示した静電レンズ
３４は、接地された入射側電極５と出射側電極７の間
に、減速用レンズ電源１４から＋１０．５ｋＶの電圧を
印可される減速用電極１２及び加速用レンズ電源１３か
ら−３０．０ｋＶの電圧を印可される加速用電極１６を
備える。FIG. 2 is a schematic view showing an example in which another electrostatic lens according to the present invention is applied to a focused ion beam processing / observing apparatus. Ion beam 2 emitted from ion source 1
Passes through the condenser lens 18 and the deflector 15 and enters the electrostatic lens 34. The electrostatic lens 34 shown in this example has a decelerating electrode 12 and an accelerating lens to which a voltage of +10.5 kV is applied from the decelerating lens power supply 14 between the grounded incident-side electrode 5 and the output-side electrode 7. An acceleration electrode 16 to which a voltage of -30.0 kV is applied from a power supply 13 is provided.
【００２０】この加工・観察装置は、観察視野をなるべ
く広くとる必要があり、なるべく大きな焦点距離ｆの状
態で、かつ、収差も小さい対物レンズが必要とされる。
そこで、図２に示した静電レンズ３４では、入射イオン
ビーム２は、減速用電極１２により、まず減速され、集
束作用を受けて、次に加速用電極１６で加速されるよう
に設計されている。更に、このイオンビームは出射側電
極７で静電レンズ入射前のエネルギーに戻されて静電レ
ンズ３４から出てゆくが、出射側電極７の位置でのイオ
ンの運動エネルギー（３０ｋｅＶ）は減速用電極１２の
位置でのイオンの運動エネルギー（約１９．５ｋｅＶ）
に比べて大きく、出射側電極７による集束作用は減速用
電極１２による集束作用に比べて極めて小さいので、集
束作用の中心（レンズ主面）は減速用電極１２の部分に
ある。そこで、後述するような加速の後に減速する方式
の加減速レンズ（図３）によるよりも長い焦点距離の状
態で加工・観察用試料１７に焦点を結んでいる。This processing / observing apparatus needs to have an observation field of view as wide as possible, and requires an objective lens having a focal length f as large as possible and having a small aberration.
Therefore, the electrostatic lens 34 shown in FIG. 2 is designed so that the incident ion beam 2 is first decelerated by the deceleration electrode 12, receives a focusing action, and is then accelerated by the acceleration electrode 16. I have. Further, the ion beam is returned to the energy before the incidence of the electrostatic lens at the emission electrode 7 and exits the electrostatic lens 34. The kinetic energy (30 keV) of the ion at the position of the emission electrode 7 is used for deceleration. Kinetic energy of the ion at the position of the electrode 12 (about 19.5 keV)
Since the focusing action of the emission side electrode 7 is much smaller than that of the deceleration electrode 12, the center of the focusing action (the lens main surface) is located at the deceleration electrode 12. Therefore, the processing / observation sample 17 is focused on with a longer focal length than that of an acceleration / deceleration lens (FIG. 3) of a type that decelerates after acceleration as described later.
【００２１】この例では、入射側電極５と減速用電極１
２の間隔を２ｍｍ、減速用電極１２と加速用電極１６の
間隔を５ｍｍ、加速用電極１６と出射用電極７の間隔を
４ｍｍとした条件の下に、１６．４ｍｍの焦点距離ｆ、
及び３３．３ｍｍの色収差係数Ｃcを得た。イオンビー
ム２の偏向可能な角度をδとすると、この装置を走査型
イオン顕微鏡として使用したときの観察視野は図２に図
示されているようにほぼ２δ・ｆであり、焦点距離ｆが
大きいほど視野を広く取ることができることは容易に理
解される。In this example, the incident side electrode 5 and the deceleration electrode 1
2 is 2 mm, the distance between the deceleration electrode 12 and the acceleration electrode 16 is 5 mm, and the distance between the acceleration electrode 16 and the emission electrode 7 is 4 mm.
And a chromatic aberration coefficient Cc of 33.3 mm. Assuming that the angle at which the ion beam 2 can be deflected is δ, the observation field of view when this apparatus is used as a scanning ion microscope is approximately 2δ · f as shown in FIG. It is easily understood that a wide field of view can be taken.
【００２２】図３は、本発明による他の静電レンズをイ
オンビーム像縮小投影装置に応用した例を示す概略図で
ある。イオン源１から発射され３０ｋｅＶに加速された
イオンビーム２は、コンデンサーレンズ１８によりほぼ
平行なビームとされてイオン像投影用試料である転写マ
スク１９を照射する。転写マスク１９は、イオンビーム
に対して透明な部分と不透明な部分を有する金属板でで
きている。転写マスク１９の透明な部分を透過したイオ
ンビームは、静電レンズ４４に入り、光学式縮小投影露
光装置と同じ原理により、転写マスク１９の縮小像がレ
チクル２０に投影されるように集束する。FIG. 3 is a schematic diagram showing an example in which another electrostatic lens according to the present invention is applied to an ion beam image reduction projection apparatus. The ion beam 2 emitted from the ion source 1 and accelerated to 30 keV is converted into a substantially parallel beam by a condenser lens 18 and irradiates a transfer mask 19 as an ion image projection sample. The transfer mask 19 is made of a metal plate having a portion transparent and an opaque portion to the ion beam. The ion beam transmitted through the transparent portion of the transfer mask 19 enters the electrostatic lens 44 and is focused so that the reduced image of the transfer mask 19 is projected on the reticle 20 by the same principle as that of the optical reduction projection exposure apparatus.
【００２３】このイオンビーム像縮小投影装置では、静
電レンズ４４は、収差低減の観点から、なるべく像面側
焦点距離を短くして使いたい。そこで、静電レンズ４４
は、レンズに入ったイオンビームをまず加速し、次に減
速して集束する構成になっている。すなわち、転写マス
ク１９の１点から発射したイオンビームは、加速用レン
ズで電源１３から−３０ｋＶの電圧が印加された加速用
電極１６により約６０ｋｅＶに加速され、次に１６．７
ｋＶの電圧が印加された減速用電極１２により減速され
て、静電レンズ４４より８ｍｍ離れたレチクル２０の上
に集束する。In this ion beam image reduction projection apparatus, it is desirable to use the electrostatic lens 44 with the image plane side focal length as short as possible from the viewpoint of aberration reduction. Therefore, the electrostatic lens 44
Has a configuration in which the ion beam entering the lens is first accelerated, then decelerated and focused. That is, the ion beam emitted from one point of the transfer mask 19 is accelerated to about 60 keV by the acceleration electrode 16 to which a voltage of -30 kV is applied from the power supply 13 by the acceleration lens, and then to 16.7.
The beam is decelerated by the deceleration electrode 12 to which the voltage of kV is applied, and is focused on the reticle 20 at a distance of 8 mm from the electrostatic lens 44.
【００２４】この条件で静電レンズ４４の色収差係数Ｃ
cは２５．２ｍｍ、焦点距離ｆは１２．６ｍｍである。
Ｃc／ｆは図２で説明した静電レンズと同程度である
が、レンズ主面が減速用電極１２の部分にあるので、焦
点距離ｆが短くなっている。焦点距離ｆは図２に示した
静電レンズの約２／３であり、レチクル２０上にボケの
少ない良質のイオンビーム投影像を得ることができる。Under these conditions, the chromatic aberration coefficient C of the electrostatic lens 44
c is 25.2 mm and the focal length f is 12.6 mm.
Cc / f is almost the same as that of the electrostatic lens described with reference to FIG. 2, but the focal length f is short because the main lens surface is located at the deceleration electrode 12. The focal length f is about ／ of that of the electrostatic lens shown in FIG. 2, and a high-quality ion beam projected image with little blur on the reticle 20 can be obtained.
【００２５】図３に示した例では、減速用電極１２に印
加する電圧としてイオンビーム加速用電源３で発生した
電圧を電気抵抗器２１で分圧して使っている。荷電粒子
線を減速するのに必要な電圧は荷電粒子源１に印加する
加速電圧と同じ極性の電圧なので、イオンビーム加速用
電源３で発生した電圧を分圧して使うことができる。こ
の例では、静電レンズ４４の焦点合わせを加速用レンズ
電源１３の出力電圧調節により行っていることは言うま
でもない。In the example shown in FIG. 3, a voltage generated by the ion beam acceleration power supply 3 is divided by an electric resistor 21 and used as a voltage applied to the deceleration electrode 12. Since the voltage required to decelerate the charged particle beam has the same polarity as the acceleration voltage applied to the charged particle source 1, the voltage generated by the ion beam acceleration power supply 3 can be divided and used. In this example, it goes without saying that the focusing of the electrostatic lens 44 is performed by adjusting the output voltage of the acceleration lens power supply 13.
【００２６】[0026]
【発明の効果】本発明によると、従来の静電レンズを減
速モードで使用した場合に比べて色収差係数がほぼ２／
３以下に小さい静電レンズを実現することができ、この
静電レンズを集束イオンビーム装置に使用することによ
ってイオンビームをより細く絞ることが可能になる。ま
た、本発明の静電レンズを、イオンビーム投影装置に使
用すると、従来の静電レンズを使った場合に比べてより
シャープな像をレチクル上に投影することができる。According to the present invention, the chromatic aberration coefficient is almost 2 / compared to the case where the conventional electrostatic lens is used in the deceleration mode.
An electrostatic lens smaller than 3 can be realized, and by using this electrostatic lens in a focused ion beam device, it becomes possible to narrow the ion beam more finely. Further, when the electrostatic lens of the present invention is used in an ion beam projector, a sharper image can be projected on a reticle as compared with a case where a conventional electrostatic lens is used.
【図１】本発明による静電レンズの一例を説明する概略
図。FIG. 1 is a schematic diagram illustrating an example of an electrostatic lens according to the present invention.
【図２】本発明による他の静電レンズを集束イオンビー
ム加工・観察装置に応用した例を示す概略図。FIG. 2 is a schematic view showing an example in which another electrostatic lens according to the present invention is applied to a focused ion beam processing / observing apparatus.
【図３】本発明による他の静電レンズをイオンビーム像
縮小投影装置に応用した例を示す概略図。FIG. 3 is a schematic diagram showing an example in which another electrostatic lens according to the present invention is applied to an ion beam image reduction projection device.
【図４】従来の静電レンズの構造を示す概略図。FIG. 4 is a schematic view showing the structure of a conventional electrostatic lens.
１…イオン源、２…イオンビーム、３…イオンビーム加
速用電源、４…静電レンズ、５…入射側電極、６…中間
電極、７…出射側電極、８…レンズ電源、９…ターゲッ
ト、１０…加速用第１電極、１１…加速用第２電極、１
２…減速用電極、１３…加速用レンズ電源、１４…減速
用レンズ電源、１５…偏向器、１６…加速用電極、１７
…加工・観察用試料、１８…コンデンサーレンズ、１９
…転写マスク、２０…レチクル、２１…電気抵抗器、２
４…静電レンズ、２５…加速電極、３４…静電レンズ、
４４…静電レンズDESCRIPTION OF SYMBOLS 1 ... Ion source, 2 ... Ion beam, 3 ... Ion beam acceleration power supply, 4 ... Electrostatic lens, 5 ... Incident side electrode, 6 ... Intermediate electrode, 7 ... Outgoing side electrode, 8 ... Lens power supply, 9 ... Target, 10: first electrode for acceleration, 11: second electrode for acceleration, 1
2: Electrode for deceleration, 13: Lens power supply for acceleration, 14: Lens power supply for deceleration, 15: Deflector, 16: Electrode for acceleration, 17
… Sample for processing and observation, 18… Condenser lens, 19
... Transfer mask, 20 ... Reticle, 21 ... Electric resistor, 2
4 ... electrostatic lens, 25 ... acceleration electrode, 34 ... electrostatic lens,
44 ... Electrostatic lens
Claims (6)
線を加速する加速用電極と減速する減速用電極とを設け
たことを特徴とする静電レンズ。1. An electrostatic lens, wherein an acceleration electrode for accelerating an incident charged particle beam and a deceleration electrode for deceleration are provided inside the electrostatic lens.
ンズに入射した荷電粒子線が、まず減速され、次いで加
速されるように前記加速用電極及び減速用電極を配置し
たことを特徴とする静電レンズ。2. The electrostatic lens according to claim 1, wherein the acceleration electrode and the deceleration electrode are arranged such that the charged particle beam incident on the lens is first decelerated and then accelerated. Electrostatic lens.
ンズに入射した荷電粒子線が、まず加速され、次いで減
速されるように前記加速用電極及び減速用電極を配置し
たことを特徴とする静電レンズ。3. The electrostatic lens according to claim 1, wherein the acceleration electrode and the deceleration electrode are arranged such that the charged particle beam incident on the lens is first accelerated and then decelerated. Electrostatic lens.
記減速用電極に荷電粒子線加速用電源の電圧を分圧して
供給することを特徴とする静電レンズ。4. The electrostatic lens according to claim 1, wherein a voltage of a charged particle beam acceleration power supply is divided and supplied to the deceleration electrode.
面を荷電粒子線照射用試料面に対応させた請求項１〜４
のいずれか１項に記載の静電レンズを備えることを特徴
とする荷電粒子線集束装置。5. The charged particle beam focusing objective lens according to claim 1, wherein an image plane corresponds to a charged particle beam irradiation sample surface.
A charged particle beam focusing apparatus comprising the electrostatic lens according to any one of the above.
物面を荷電粒子線像投影用試料面に対応させた請求項１
〜４のいずれか１項に記載の静電レンズを備えることを
特徴とする荷電粒子線投影装置。6. An objective lens for projecting a charged particle beam image,
2. An object surface corresponding to a sample surface for projecting a charged particle beam image.
A charged particle beam projection apparatus, comprising the electrostatic lens according to any one of claims 1 to 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04189597A JP3862344B2 (en) | 1997-02-26 | 1997-02-26 | Electrostatic lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04189597A JP3862344B2 (en) | 1997-02-26 | 1997-02-26 | Electrostatic lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10241616A true JPH10241616A (en) | 1998-09-11 |
| JP3862344B2 JP3862344B2 (en) | 2006-12-27 |
Family
ID=12621031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04189597A Expired - Fee Related JP3862344B2 (en) | 1997-02-26 | 1997-02-26 | Electrostatic lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3862344B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006210456A (en) * | 2005-01-26 | 2006-08-10 | Canon Inc | Electrostatic lens apparatus, method of regulating it and electrically-charged particle beam exposure device using the electrostatic lens apparatus |
| WO2007127086A2 (en) * | 2006-04-26 | 2007-11-08 | Axcelis Technologies, Inc. | Methods and systems for trapping ion beam particles and focusing an ion beam |
| WO2008023558A1 (en) * | 2006-08-23 | 2008-02-28 | Sii Nanotechnology Inc. | Charged particle beam apparatus |
| JP2008543014A (en) * | 2005-06-03 | 2008-11-27 | シーイービーティー・カンパニー・リミティッド | Ultra-small electron column with simple structure |
| EP1314181B1 (en) * | 2000-09-01 | 2008-12-10 | Axcelis Technologies, Inc. | Electrostatic trap for particles entrained in an ion beam |
| DE112009000768T5 (en) | 2008-03-26 | 2011-02-24 | Horiba Ltd. | Electrostatic lens for charged particle radiation |
| EP2672501A1 (en) * | 2012-06-07 | 2013-12-11 | Fei Company | Focused charged particle column for operation at different beam energies at a target |
-
1997
- 1997-02-26 JP JP04189597A patent/JP3862344B2/en not_active Expired - Fee Related
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1314181B1 (en) * | 2000-09-01 | 2008-12-10 | Axcelis Technologies, Inc. | Electrostatic trap for particles entrained in an ion beam |
| JP2006210456A (en) * | 2005-01-26 | 2006-08-10 | Canon Inc | Electrostatic lens apparatus, method of regulating it and electrically-charged particle beam exposure device using the electrostatic lens apparatus |
| JP2008543014A (en) * | 2005-06-03 | 2008-11-27 | シーイービーティー・カンパニー・リミティッド | Ultra-small electron column with simple structure |
| WO2007127086A2 (en) * | 2006-04-26 | 2007-11-08 | Axcelis Technologies, Inc. | Methods and systems for trapping ion beam particles and focusing an ion beam |
| US7598495B2 (en) | 2006-04-26 | 2009-10-06 | Axcelis Technologies, Inc. | Methods and systems for trapping ion beam particles and focusing an ion beam |
| WO2007127086A3 (en) * | 2006-04-26 | 2008-03-27 | Axcelis Tech Inc | Methods and systems for trapping ion beam particles and focusing an ion beam |
| JP2008053001A (en) * | 2006-08-23 | 2008-03-06 | Sii Nanotechnology Inc | Charged particle beam device |
| WO2008023558A1 (en) * | 2006-08-23 | 2008-02-28 | Sii Nanotechnology Inc. | Charged particle beam apparatus |
| US20090302233A1 (en) * | 2006-08-23 | 2009-12-10 | Takashi Ogawa | Charged particle beam apparatus |
| TWI409846B (en) * | 2006-08-23 | 2013-09-21 | Sii Nanotechnology Inc | Charged particle beam device |
| DE112009000768T5 (en) | 2008-03-26 | 2011-02-24 | Horiba Ltd. | Electrostatic lens for charged particle radiation |
| US8669534B2 (en) | 2008-03-26 | 2014-03-11 | Horiba, Ltd. | Electrostatic lens for charged particle radiation |
| EP2672501A1 (en) * | 2012-06-07 | 2013-12-11 | Fei Company | Focused charged particle column for operation at different beam energies at a target |
| US8742361B2 (en) | 2012-06-07 | 2014-06-03 | Fei Company | Focused charged particle column for operation at different beam energies at a target |
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| Publication number | Publication date |
|---|---|
| JP3862344B2 (en) | 2006-12-27 |
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