JPH0234417B2 - - Google Patents
Info
- Publication number
- JPH0234417B2 JPH0234417B2 JP57187869A JP18786982A JPH0234417B2 JP H0234417 B2 JPH0234417 B2 JP H0234417B2 JP 57187869 A JP57187869 A JP 57187869A JP 18786982 A JP18786982 A JP 18786982A JP H0234417 B2 JPH0234417 B2 JP H0234417B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic pole
- pole piece
- excitation
- objective lens
- saturation
- 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.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/04—Arrangements of electrodes and associated parts for generating or controlling the discharge, e.g. electron-optical arrangement or ion-optical arrangement
- H01J37/10—Lenses
- H01J37/14—Lenses magnetic
- H01J37/141—Electromagnetic lenses
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
Description
【発明の詳細な説明】
本発明は、走査型電子顕微鏡や電子線露光装置
あるいはＸ線マイクロアナライザ等に用いられる
電磁式対物レンズに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic objective lens used in a scanning electron microscope, an electron beam exposure apparatus, an X-ray microanalyzer, or the like.
従来の走査型電子顕微鏡等の電磁式対物レンズ
としては、第１図に示すようなものがあり、相互
間に長さがＳのレンズ形成用〓間を有する上部磁
極片１および下部磁極片２が設けられており、こ
れらの磁極片１，２は、励磁コイル３を内蔵する
ヨーク４によつて連結されている。 As a conventional electromagnetic objective lens for a scanning electron microscope, etc., there is one as shown in FIG. These magnetic pole pieces 1 and 2 are connected by a yoke 4 containing an excitation coil 3.
また、各磁極片１，２には、電子線通過孔５，
６が形成されている。 Further, each magnetic pole piece 1, 2 has an electron beam passage hole 5,
6 is formed.
なお、第１図中の符号７，８は偏向コイル、９
は傾動可能な試料を示している。 In addition, symbols 7 and 8 in FIG. 1 are deflection coils, and 9
indicates a tiltable sample.
しかしながら、従来の電磁式対物レンズでは、
球面収差を小さくするために、励磁を強くして、
レンズ主面と試料９との距離Z0を短くすれば、試
料９が対物レンズ下部磁極片２に当たらないよう
な配慮をしなければならず、これにより試料９の
傾斜角θが試料９の大きさについての大幅な制限
を受けてしまう。 However, with conventional electromagnetic objective lenses,
In order to reduce spherical aberration, the excitation is strengthened,
If the distance Z 0 between the main surface of the lens and the sample 9 is shortened, care must be taken to prevent the sample 9 from hitting the lower magnetic pole piece 2 of the objective lens. There are significant size restrictions.
そこで、第２図に鎖線で示すごとく、磁極片
１，２間の〓間長S′を従来のものＳよりも長くし
て、半値幅Ｗ１を従来のものＷよりも広くするこ
とにより、球面収差を小さくしたり、第３図に示
すごとく、下部磁極片２の電子線通過孔径Ｄ１′
を従来のものＤ１よりも大きくして、半値幅Ｗ２
を従来のものＷよりも広することにより、球面収
差を小さくしたりすることも考えられるが、いず
れの場合も次のような問題点がある。 Therefore, as shown by the chain line in Fig. 2, the distance S' between the magnetic pole pieces 1 and 2 is made longer than that of the conventional one S, and the half-width W1 is made wider than that of the conventional one. In order to reduce aberrations, as shown in FIG.
is larger than the conventional one D1, and the half width W2
It is also possible to reduce the spherical aberration by making W wider than the conventional W, but in either case, the following problems arise.
まず、第２図に鎖線で示す従来の電磁式対物レ
ンズでは、軸上磁場分布ｂが従来のものａに比べ
て第２図に示すようになるので、レンズ主面がレ
ンズ上方（電子銃側５へ上がつてしまい、これに
より焦点距離が長くなつて、その結果焦点距離に
ほぼ比例する色収差係数が大きくなつて、分解能
が悪くなるという問題点がある。 First, in the conventional electromagnetic objective lens shown by the chain line in Fig. 2, the axial magnetic field distribution b becomes as shown in Fig. 2 compared to the conventional one a, so that the main surface of the lens is located above the lens (on the electron gun side). 5, which increases the focal length, resulting in an increase in the chromatic aberration coefficient, which is approximately proportional to the focal length, resulting in poor resolution.
また、第３図に示す従来の電磁式対物レンズで
は、軸上磁場分布ｃが従来のものａに比べレンズ
下方（試料側）にまで拡がるため、距離Z0（第１
図参照）を短くすれば、試料９が軸上磁場分布ｃ
の強い磁場内に置かれてしまい、２次電子の検出
が困難になつて、試料観察を十分に行なえないと
いう問題点がある。 Furthermore, in the conventional electromagnetic objective lens shown in FIG .
(see figure), sample 9 has an axial magnetic field distribution c
There is a problem in that the sample is placed in a strong magnetic field, making it difficult to detect secondary electrons and making it impossible to observe the sample adequately.
本発明は、これらの問題点を解決しようとする
もので、色収差を悪くすることなく球面収差を改
善できるようにした、電磁式対物レンズを提供す
ることを目的とする。 The present invention aims to solve these problems, and aims to provide an electromagnetic objective lens that can improve spherical aberration without worsening chromatic aberration.
このため、本発明の電磁式対物レンズは、荷電
粒子線通過孔を有し相互間にレンズ形成用〓間を
有する上部磁極片および下部磁極片をそなえ、球
面収差を改善すべく、上記上部磁極片の下部磁極
片側端部が、弱励磁で磁気飽和を起こす弱励磁磁
気飽和部として構成されて、同弱励磁磁気飽和部
が、上記上部磁極片から上記下部磁極片へ向けて
突出した肉厚の著しく薄い筒状部として形成され
ていることを特徴としている。 Therefore, the electromagnetic objective lens of the present invention is provided with an upper magnetic pole piece and a lower magnetic pole piece that have a charged particle beam passing hole and a gap for forming a lens between them. One end of the lower magnetic pole of the piece is configured as a weakly excitation magnetic saturation part that causes magnetic saturation with weak excitation, and the weakly excitation magnetic saturation part has a wall thickness that protrudes from the upper magnetic pole piece toward the lower magnetic pole piece. It is characterized by being formed as an extremely thin cylindrical part.
以下、図面により本発明の一実施例としての走
査型電子顕微鏡用電磁式対物レンズについて説明
すると、第４図はその要部断面図、第５図はその
縦断面状態とその軸上磁場分布とを共に示す説明
図、第６〜８図はそれぞれの変形例を示す要部断
面図であり、各図中、第１〜３図と同じ符号はほ
ぼ同様の部分を示している。 Below, an electromagnetic objective lens for a scanning electron microscope as an embodiment of the present invention will be explained with reference to the drawings. FIG. 4 is a cross-sectional view of the main part thereof, and FIG. 5 is a longitudinal cross-sectional state and its axial magnetic field distribution. and FIGS. 6 to 8 are sectional views of essential parts showing respective modifications, and in each figure, the same reference numerals as in FIGS. 1 to 3 indicate substantially the same parts.
第４図に示すごとく、上部磁極片１′と下部磁
極片２とが設けられており、これらの磁極片１′，
２は、電子線通過孔（荷電粒子線通過孔）５，６
を有し、且つ、相互間に長さＳ１（＜Ｓ）のレン
ズ形成用〓間を有している。 As shown in FIG. 4, an upper magnetic pole piece 1' and a lower magnetic pole piece 2 are provided, and these magnetic pole pieces 1',
2 is an electron beam passing hole (charged particle beam passing hole) 5, 6
and a lens-forming space having a length S1 (<S) between them.
また、上部磁極片１′の下部磁極片側端部１′ａ
が、図示のごとく他の部分よりも著しく肉厚の薄
い筒状部として、上部磁極片１′から下部磁極片
２へ向け突出するように形成されており、これに
よりこの筒状部１′ａは、弱い励磁でもすぐに磁
気飽和を起こす弱励磁磁気飽和部として構成され
ていることになる。 Also, one end 1'a of the lower magnetic pole of the upper magnetic pole piece 1'
As shown in the figure, it is formed as a cylindrical part with a wall thickness significantly thinner than other parts so as to protrude from the upper magnetic pole piece 1' toward the lower magnetic pole piece 2, so that this cylindrical part 1'a is configured as a weakly excitation magnetic saturation section that immediately causes magnetic saturation even with weak excitation.
なお、弱励磁磁気飽和部１′ａの基端から下部
磁極片２の上面までの距離ｌは、従来の対物レン
ズにおける〓間長Ｓよりも長く設定されてい。 Note that the distance l from the base end of the weakly excitation magnetic saturation portion 1'a to the upper surface of the lower magnetic pole piece 2 is set longer than the distance S in a conventional objective lens.
また、第４図中の符号Ｄ２は弱励磁磁気飽和部
１′ａにおける電子線通過孔径を示しており、こ
の孔径Ｄ２は下部磁極片２の電子線通過孔径Ｄ１
よりも大く設定されている。 Further, reference numeral D2 in FIG. 4 indicates the diameter of the electron beam passage hole in the weakly excited magnetic saturation section 1'a, and this hole diameter D2 is the diameter D1 of the electron beam passage hole in the lower magnetic pole piece 2.
is set larger than .
このように、上部磁極片１′の下部磁極片側端
部１′ａを弱励磁磁気飽和部として構成するとと
もに、Ｓ１，ｌをＳ１＜Ｓ＜ｌなる関係に設定し
ているので、第５図に示すごとく、対物レンズの
主面の位置を従来のものａとほぼ同じ位置に保
ち、しかも磁気分布がレンズ下方へ拡がらないよ
うにしながら、半値幅Ｗ３を従来のものＷに比べ
広くすることがきる。これにより第１図に示すZ0
を長くすることなく、その結果色収差係数を悪く
しないで、しかも球面収差係数を小さくすること
ができるので、分解能をあげ、極めて高いレンズ
性能を発揮することができる。 In this way, one end 1'a of the lower magnetic pole of the upper magnetic pole piece 1' is configured as a weakly excitation magnetic saturation part, and S1,l are set to the relationship S1<S<l, so that As shown in , the half-width W3 is made wider than that of the conventional lens W while keeping the main surface of the objective lens at approximately the same position as the conventional lens a and preventing the magnetic distribution from expanding downwards of the lens. I'm struggling. As a result, Z 0 shown in Figure 1
Since it is possible to reduce the spherical aberration coefficient without increasing the length, and as a result, without worsening the chromatic aberration coefficient, the resolution can be increased and extremely high lens performance can be achieved.
なお、第６図に示すごとく、上部磁極片１′か
ら下部磁極片２へ向けて突出した肉厚の著しく薄
い筒状部としての下部磁極片側端部１′ｂの下端
にフランジ１′ｃを形成すれば、第４図の場合に
比べて、この部分１′ｂの磁気飽和をさらに弱い
励磁で行なうことができる。 As shown in FIG. 6, a flange 1'c is provided at the lower end of one end 1'b of the lower magnetic pole, which is a cylindrical part with a very thin wall that protrudes from the upper magnetic pole piece 1' toward the lower magnetic pole piece 2. If formed, magnetic saturation of this portion 1'b can be achieved with weaker excitation than in the case of FIG.
また、第７図に示すごとく、上部磁極片１′の
下部磁極片側端部１d′を、他の部分よりも飽和磁
束密度の小さい材質（例えば純鉄やフエライト、
パーマロイ）の部材で構成して、この部分１′ｄ
で弱励磁磁気飽和部を構成してもよく、さらに第
８図に示すように、純鉄あるいはフエライトやパ
ーマロイ等の飽和磁束密度の小さい材料で構成さ
れた肉厚の著しく薄い筒体の基部を下部磁極片
１′の他の部分に挿入して、筒状部としての弱励
磁磁気飽和部１e′を構成してもよく、いずれの場
合も、色収差を悪くすることなく球面収差を大幅
に改善することができる。 In addition, as shown in FIG. 7, one end 1d' of the lower magnetic pole of the upper magnetic pole piece 1' is made of a material having a lower saturation magnetic flux density than other parts (for example, pure iron, ferrite, etc.).
This part 1'd
Furthermore, as shown in Fig. 8, the base of a cylinder with an extremely thin wall made of a material with a low saturation magnetic flux density such as pure iron or ferrite or permalloy may be used. It may be inserted into another part of the lower magnetic pole piece 1' to form a weakly excited magnetic saturation part 1e' as a cylindrical part. In either case, spherical aberration can be significantly improved without worsening chromatic aberration. can do.
なお、上部磁極片１′、下部磁極片２およびヨ
ーク４は純鉄のごとき軟鋼製である。 Note that the upper magnetic pole piece 1', the lower magnetic pole piece 2, and the yoke 4 are made of mild steel such as pure iron.
なお、本対物レンズは、走査型電子顕微鏡に限
らず、これに類似の装置にも摘用できることはい
うまでもない。 It goes without saying that this objective lens can be used not only for scanning electron microscopes but also for similar devices.
以上詳述したように、本発明の電磁式対物レン
ズによれば、上部磁極片の下部磁極片側端部に、
同上部磁極片から下部磁極片へ向けて突出した肉
厚の著しく薄い筒状部として、弱励磁で磁気飽和
を起こす弱励磁磁気飽和部が構成されているの
で、色収差を悪くすることなく球面収差を大幅に
改善できる利点がある。 As detailed above, according to the electromagnetic objective lens of the present invention, at one end of the lower magnetic pole of the upper magnetic pole piece,
The weakly excitation magnetic saturation part, which causes magnetic saturation with weak excitation, is configured as a cylindrical part with an extremely thin wall that protrudes from the upper magnetic pole piece toward the lower magnetic pole piece, so that spherical aberration can be reduced without worsening chromatic aberration. It has the advantage of being able to significantly improve
第１図は従来の電磁式対物レンズを示す縦断面
図であり、第２図は従来の異なる２つの電磁式対
物レンズについてその縦断面状態とその軸上磁場
分布とを共に示す説明図であり、第３図は他の従
来の電磁式対物レンズを第２図に対応させて示す
説明図であり、第４〜８図は本発明の一実施例と
しての電磁式対物レンズを示すもので、第４図は
その要部断面図、第５図はその縦断面状態とその
軸上磁場分布とを共に示す説明図、第６〜８図は
それぞれその変形例を示す要部断面図である。
１′……上部磁極片、１′ａ，１′ｂ……弱励磁
磁気飽和部としての筒状部、１′ｃ……フランジ、
１′ｄ，１′ｅ……弱励磁磁気飽和部としての筒状
部、２……下部磁極片、３……励磁コイル、４…
…ヨーク、５，６……荷電粒子線通過孔としての
電子線通過孔、７，８……偏向コイル、９……試
料。
FIG. 1 is a longitudinal cross-sectional view showing a conventional electromagnetic objective lens, and FIG. 2 is an explanatory diagram showing both the longitudinal cross-sectional state and the axial magnetic field distribution of two different conventional electromagnetic objective lenses. , FIG. 3 is an explanatory diagram showing another conventional electromagnetic objective lens corresponding to FIG. 2, and FIGS. 4 to 8 show electromagnetic objective lenses as an embodiment of the present invention. FIG. 4 is a sectional view of the main part thereof, FIG. 5 is an explanatory diagram showing both the longitudinal sectional state and the axial magnetic field distribution thereof, and FIGS. 6 to 8 are sectional views of the main part showing modifications thereof. 1'... Upper magnetic pole piece, 1'a, 1'b... Cylindrical part as a weakly excited magnetic saturation part, 1'c... Flange,
1'd, 1'e... Cylindrical part as weak excitation magnetic saturation part, 2... Lower magnetic pole piece, 3... Excitation coil, 4...
... Yoke, 5, 6 ... Electron beam passage hole as a charged particle beam passage hole, 7, 8 ... Deflection coil, 9 ... Sample.
Claims (1)
用〓間を有する上部磁極片および下部磁極片をそ
なえ、球面収差を改善すべく、上記上部磁極片の
下部磁極片側端部が、弱励磁で磁気飽和を起こす
弱励磁磁気飽和部として構成されて、同弱励磁磁
気飽和部が、上記上部磁極片から上記下部磁極片
へ向けて突出した肉厚の著しく薄い筒状部として
形成されていることを特徴とする、電磁式対物レ
ンズ。 ２ 上記の肉厚の著しく薄い筒状部が、飽和磁束
密度の小さい材質で形成されている、特許請求の
範囲第１項に記載の電磁式対物レンズ。[Claims] 1. An upper magnetic pole piece and a lower magnetic pole piece having a charged particle beam passing hole and a lens-forming space between them, and one side of the lower magnetic pole of the upper magnetic pole piece in order to improve spherical aberration. The end portion is configured as a weakly excitation magnetic saturation part that causes magnetic saturation with weak excitation, and the weakly excitation magnetic saturation part has a cylindrical shape with an extremely thin wall that protrudes from the upper magnetic pole piece to the lower magnetic pole piece. An electromagnetic objective lens characterized in that it is formed as a section. 2. The electromagnetic objective lens according to claim 1, wherein the extremely thin cylindrical portion is made of a material with a low saturation magnetic flux density.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57187869A JPS5978433A (en) | 1982-10-26 | 1982-10-26 | Electromagnetic objective lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57187869A JPS5978433A (en) | 1982-10-26 | 1982-10-26 | Electromagnetic objective lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5978433A JPS5978433A (en) | 1984-05-07 |
| JPH0234417B2 true JPH0234417B2 (en) | 1990-08-03 |
Family
ID=16213636
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57187869A Granted JPS5978433A (en) | 1982-10-26 | 1982-10-26 | Electromagnetic objective lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5978433A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2530095B2 (en) * | 1993-04-26 | 1996-09-04 | 株式会社日立製作所 | Scanning electron microscope |
| JP2009205936A (en) * | 2008-02-28 | 2009-09-10 | Hitachi High-Technologies Corp | Scanning electron microscope |
-
1982
- 1982-10-26 JP JP57187869A patent/JPS5978433A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5978433A (en) | 1984-05-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9390882B2 (en) | Apparatus having a magnetic lens configured to diverge an electron beam | |
| US10332718B1 (en) | Compact deflecting magnet | |
| US4419581A (en) | Magnetic objective lens for use in a scanning electron microscope | |
| EP0084653B1 (en) | Composite concentric-gap magnetic lens | |
| US4219732A (en) | Magnetic electron lens | |
| US5111494A (en) | Magnet for use in a drift tube of an x-ray tube | |
| US5023457A (en) | Electron beam device | |
| JPH0234417B2 (en) | ||
| EP0085323B1 (en) | Electromagnetic lens polepiece structure | |
| JPH1069871A (en) | Deflection device | |
| Tsuno et al. | Magnetic-field-free objective lens around a specimen for observing fine structure of ferromagnetic materials in a transmission electron microscope | |
| JPS5978434A (en) | Electromagnetic objective | |
| NL2034496B1 (en) | Electro-magnetic lens for charged particle apparatus. | |
| JPS5845782B2 (en) | Objective lenses for scanning electron microscopes, etc. | |
| US2910589A (en) | Pole shoe for magnetic electron lens | |
| US6624426B2 (en) | Split magnetic lens for controlling a charged particle beam | |
| JPH05225936A (en) | Object lens for scanning electron microscope | |
| EP0281190B1 (en) | Magnetic focusing lens for a cathode ray tube | |
| JPS6341184B2 (en) | ||
| JPH0136666B2 (en) | ||
| JPH0622102B2 (en) | Cathode ray tube | |
| JPS5913141B2 (en) | Objective lenses for scanning electron microscopes, etc. | |
| JPH0828200B2 (en) | Electromagnetic lens | |
| JPH0422054A (en) | Objective lens of transmission type electron microscope | |
| JPS6335065B2 (en) |