JPH0760656B2 - electronic microscope - Google Patents
electronic microscopeInfo
- Publication number
- JPH0760656B2 JPH0760656B2 JP1248794A JP24879489A JPH0760656B2 JP H0760656 B2 JPH0760656 B2 JP H0760656B2 JP 1248794 A JP1248794 A JP 1248794A JP 24879489 A JP24879489 A JP 24879489A JP H0760656 B2 JPH0760656 B2 JP H0760656B2
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- JP
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- Prior art keywords
- focusing lens
- focus
- depth
- objective
- lens
- Prior art date
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- 239000000523 sample Substances 0.000 claims description 46
- 238000010894 electron beam technology Methods 0.000 claims description 16
- 230000005284 excitation Effects 0.000 description 10
- 230000000694 effects Effects 0.000 description 2
- 238000001000 micrograph Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、電子ビームを試料表面に集束して照射する電
子顕微鏡等の焦点深度調整装置に関する。Description: TECHNICAL FIELD The present invention relates to a focal depth adjusting device for an electron microscope or the like that focuses and irradiates an electron beam on a sample surface.
試料に凹凸がある場合、試料に照射する電子ビームの開
き角α４を小さくしてその焦点深度を深くしないと、電
子顕微鏡の像はボケて充分な解像力が得られない。第３
図はビームの開き角と試料表面の凹凸との関係を説明す
るための図であり、５は対物レンズ、６は試料面を示
す。図のP1に示すような試料面においてビームの焦点を
合わせても、試料６に凹凸があると、ビームは拡がって
P2に示すようにボケが生ずる。このとき、小さい開き角
のビームB1の場合には、大きい開き角のビームB2よりボ
ケの幅は小さくなる。このように、特に焦点深度が浅い
場合には、照射ビームの径が試料表面の凹凸によって大
きく変化するため、横型の波長分散型分光器やエネルギ
ー分散型分光器（EDS）のように、試料表面の凹凸に強
い（検出されるＸ線強度の変化が少ない）分光器と共に
用いる場合、それらの特徴を十分に発揮できない。した
がって、電子ビームの開き角α４を制御して、所望の焦
点深度を得ることができるものが望まれている。When the sample has irregularities, the electron microscope image is blurred and a sufficient resolution cannot be obtained unless the aperture angle α 4 of the electron beam with which the sample is irradiated is made small to deepen the depth of focus. Third
The figure is a diagram for explaining the relationship between the divergence angle of the beam and the unevenness of the sample surface. Reference numeral 5 denotes the objective lens, and 6 denotes the sample surface. Even if the beam is focused on the sample surface as shown in P1 in the figure, if the sample 6 has irregularities, the beam will spread.
Blurring occurs as shown in P2. At this time, in the case of the beam B1 having a small opening angle, the blur width is smaller than that of the beam B2 having a large opening angle. In this way, especially when the depth of focus is shallow, the diameter of the irradiation beam changes greatly due to the unevenness of the sample surface, so that the sample surface, such as a horizontal wavelength dispersive spectrometer or energy dispersive spectrometer (EDS) When used in combination with a spectroscope that is highly resistant to unevenness (the change in the detected X-ray intensity is small), these characteristics cannot be sufficiently exhibited. Therefore, it is desired to control the aperture angle α 4 of the electron beam to obtain a desired depth of focus.
ところで、従来電子線を用いる電子顕微鏡等において、
試料に照射する電子ビームの開き角α４を制御して焦点
深度を深いモードにするような装置としては、例えば、
透過型の電子顕微鏡に装着する走査像観察装置のよう
に、特定のプローブ電流に対してのみ有効な装置や、特
願昭63−64472号で提案したように、任意のプローブ電
流に対して最も焦点深度が深くなるように対物レンズ等
の焦点距離を調整するものがあった。By the way, in an electron microscope or the like using a conventional electron beam,
As an apparatus for controlling the aperture angle α 4 of the electron beam with which the sample is irradiated to set the depth of focus to the deep mode, for example,
A device that is effective only for a specific probe current, such as a scanning image observation device that is attached to a transmission electron microscope, or the most suitable for an arbitrary probe current, as proposed in Japanese Patent Application No. 63-64472. Some have adjusted the focal length of the objective lens or the like so that the focal depth becomes deep.
しかしながら、上記した従来のものにおいては、プロー
ブ電流を変えると、上記の開き角α４も変化してしま
い、焦点深度も変化してしまう。However, in the above-mentioned conventional device, when the probe current is changed, the opening angle α 4 also changes, and the depth of focus also changes.
また、電子顕微鏡の中でも、特に、電子プローブ・マイ
クロ・アナライザ（EPMA）や、オージェ・マイクロ・プ
ローブ（AP）などの分析装置を有するものでは、ブロー
ブ電流を広域に渡って変化させる。このため、このよう
な装置においては、任意のプローブ電流に対して、焦点
深度の深いモードを設定できる必要があるが、上記した
従来の焦点深度を深く調整するものにおいては、対物レ
ンズの励磁を変更しなければならず、その場合、対物レ
ンズを通過する電子ビームの磁場による旋回角の変化に
より、光軸を中心とした顕微鏡像の回転（像回転）角が
変化するため、像回転の補正が複雑になる。そして、特
に倍率が低い領域においては、電子ビームの開き角α４
を余り大きくせず、任意に焦点深度を設定できるものが
望まれている。Further, among electron microscopes, those having an analyzer such as an electron probe micro analyzer (EPMA) or an Auger micro probe (AP) change the probe current over a wide range. Therefore, in such an apparatus, it is necessary to be able to set a mode having a deep depth of focus with respect to an arbitrary probe current. However, in the above-mentioned conventional apparatus for deeply adjusting the depth of focus, the excitation of the objective lens is not performed. It must be changed. In that case, the rotation angle (image rotation) of the microscope image around the optical axis changes due to the change of the turning angle due to the magnetic field of the electron beam passing through the objective lens. Becomes complicated. Then, particularly in a region where the magnification is low, the aperture angle α 4 of the electron beam
It is desired that the depth of focus can be set arbitrarily without making the value too large.
したがって、本発明の目的は、プローブ電流を変化させ
ても焦点深度が変わらず、また、任意のプローブ電流に
対して、プローブ電流を変えることなく焦点深度を広範
に変更することが可能な電子顕微鏡等における焦点深度
調整装置を提供することである。Therefore, an object of the present invention is to provide an electron microscope capable of widely changing the depth of focus without changing the probe current with respect to an arbitrary probe current even if the probe current is changed. It is to provide a depth-of-focus adjustment device in the above.
本発明の電子顕微鏡は、電子ビームの進行方向に、電子
銃、第１集束レンズ、第２集束レンズ、対物絞り、対物
レンズを順に配置し、プローブ電流を任意に変化させた
際に、対物レンズの焦点距離を変更することなしに、設
定された焦点深度を維持するように、第１集束レンズ及
び第２集束レンズの焦点距離を制御する手段を設けたこ
とを特徴とするものである。この場合、焦点深度の設定
値の変更を、対物絞りの絞り径を変更することによって
行うように構成することができる。In the electron microscope of the present invention, the electron gun, the first focusing lens, the second focusing lens, the objective diaphragm, and the objective lens are sequentially arranged in the traveling direction of the electron beam, and the objective lens is changed when the probe current is arbitrarily changed. It is characterized in that means for controlling the focal lengths of the first focusing lens and the second focusing lens is provided so as to maintain the set focal depth without changing the focal length of. In this case, the set value of the depth of focus can be changed by changing the aperture diameter of the objective aperture.
さらに、このような装置は、プローブ電流を変えると焦
点深度も変化する通常のモードに切り換え可能に構成す
ることが望ましい。Further, it is desirable that such a device be switchable to a normal mode in which the depth of focus also changes when the probe current is changed.
対物レンズの焦点距離とは独立に第１集束レンズ及び第
２集束レンズの焦点距離を制御可能に構成したので、後
記の（2.13）と（2.14）にしたがってこれらのレンズの
焦点距離を制御することで、任意のプローブ電流に対し
て所定の焦点深度を与えることができる。Since the focal lengths of the first focusing lens and the second focusing lens can be controlled independently of the focal length of the objective lens, the focal lengths of these lenses should be controlled according to (2.13) and (2.14) below. Thus, a given depth of focus can be provided for any probe current.
次に、第１図の構成説明図を参照にして本発明の電子顕
微鏡等における焦点深度調整装置の１実施例について説
明する。Next, one embodiment of a depth-of-focus adjusting device in an electron microscope or the like of the present invention will be described with reference to the configuration explanatory view of FIG.
この電子顕微鏡は、電子銃１（Ｏ）、電子銃１から発射
された開き角α１の電子ビームを２段にわたって集束す
る第１集束レンズ２（CL1）、第２集束レンズ３（CL
2）、第２集束レンズ３によって集束された電子ビーム
中に位置する対物絞り４（AP）（この絞りに入射する第
２集束レンズ３から出たビームは必ずしも集束ビームで
ある必要はない。また、対物絞り４は、第２集束レンズ
３の上流近傍に位置していてもよい。）、対物絞り４に
よって制限された電子ビームを受け入れて試料６上に開
き角α４で結像させる対物レンズ５（OL）、第１集束レ
ンズ２励磁用電源７、第２集束レンズ３励磁用電源８、
対物レンズ５励磁用電源９、及び、制御部10からなって
いる。なお、符号６は試料を示す。This electron microscope includes an electron gun 1 (O), a first focusing lens 2 (CL1) that focuses an electron beam emitted from the electron gun 1 with an opening angle α 1 in two steps, and a second focusing lens 3 (CL
2) The objective aperture 4 (AP) located in the electron beam focused by the second focusing lens 3 (the beam emitted from the second focusing lens 3 incident on this aperture is not necessarily a focused beam. , The objective diaphragm 4 may be located in the vicinity of the upstream of the second focusing lens 3.) The objective lens which receives the electron beam limited by the objective diaphragm 4 and forms an image on the sample 6 at an opening angle α 4. 5 (OL), first focusing lens 2 excitation power supply 7, second focusing lens 3 excitation power supply 8,
The objective lens 5 includes an excitation power source 9 and a control unit 10. In addition, the code | symbol 6 shows a sample.
ところで、第１図の示すように、電子銃１と第１集束レ
ンズ２の主面との距離をＰ、第１集束レンズ２と第２集
束レンズ３の主面間の距離をＱ、第２集束レンズ３の主
面と対物絞り４との距離をＴ、対物絞り４と対物レンズ
５の主面との距離をＶ、対物レンズ５の主面と試料６と
の距離をＷとし、対物絞り４の開口の半径をrAPとす
る。このような前提の下に、本発明の装置の動作原理を
説明する。By the way, as shown in FIG. 1, the distance between the electron gun 1 and the main surface of the first focusing lens 2 is P, the distance between the main surfaces of the first focusing lens 2 and the second focusing lens 3 is Q, and the second Let T be the distance between the main surface of the focusing lens 3 and the objective diaphragm 4, V be the distance between the objective diaphragm 4 and the main surface of the objective lens 5, and W be the distance between the main surface of the objective lens 5 and the sample 6. The radius of the opening of 4 is r AP . Under such a premise, the operation principle of the device of the present invention will be described.
試料６面に対して許容し得る凹凸量±Δｌ、あるいは焦
点深度±Δｌは、CRT上で許容し得る像のボケの幅ｒ
と、観察倍率Ｍと、合焦時のプローブ径dPと、試料６へ
入射するビームの開き角α４とから、 で求められる。プローブ径dPは、プローブ電流IPとα４
の関数であるが、r/Mと比較して十分小さければ、 となる。したがって、対物レンズ５の主面におけるビー
ムの拡がりrP3は、 rP3＝α４・Ｗ ・・・・・・・（2.3） となる。対物絞り４の半径rAPは既に与えられた値なの
で、対物絞り４と第２集束レンズ３の結像点との距離Ｕ
が、 rAP/U＝rP3/（Ｕ−Ｖ） ・・（2.4） ∴Ｕ＝rAP・V/（rAP−rP3） …（2.5） として求められる。したがって、第２集束レンズ３の出
射側の開き角α３は、 α３＝rAP/U ・・・・・・・・（2.6） また、第２集束レンズ３の主面とその結像点との距離Z2
は、 Z2＝Ｔ＋Ｕ ・・・・・・・・（2.7） である。上記の（2.6）と（2.7）から、第２集束レンズ
３の主面上におけるビームの拡がりrP2が、 rP2＝α３・Z2 ・・・・・・・（2.8） で求められる。The allowable amount of unevenness ± Δl or the depth of focus ± Δl for the six surfaces of the sample is the allowable image blur width r on the CRT.
From the observation magnification M, the probe diameter d P at the time of focusing, and the divergence angle α 4 of the beam incident on the sample 6, Required by. The probe diameter d P is the probe current I P and α 4
, But if it is small enough compared to r / M, Becomes Therefore, the beam divergence r P3 on the main surface of the objective lens 5 is r P3 = α 4 · W ··· (2.3). Since the radius r AP of the objective diaphragm 4 is a value already given, the distance U between the objective diaphragm 4 and the image forming point of the second focusing lens 3 is U.
Is calculated as r AP / U = r P3 /(U−V)··(2.4) ∴U = r AP · V / (r AP− r P3 )… (2.5). Therefore, the opening angle α 3 on the exit side of the second focusing lens 3 is α 3 = r AP / U (2.6) Further, the main surface of the second focusing lens 3 and its imaging point Distance to Z 2
Is Z 2 = T + U ... (2.7). From the above (2.6) and (2.7), the divergence r P2 of the beam on the main surface of the second focusing lens 3 is obtained by r P2 = α 3 · Z 2 ··· (2.8).
一方、電子銃１の輝度をβ、その仮想光源の大きさをd9
とすれば、第１集束レンズ２の入射側のプローブ電流IP
に対応する開き角α１は、 で求められるので、IPに対応する第１集束レンズ２の主
面上のビームの拡がりrP1は、 rP1＝α１・Ｐ ・・・・・・・・（２、10） で求められる。この半径のビームが、第１集束レンズ２
と第２集束レンズ３の間で、図示のように、一旦結像
し、第２集束レンズ３の主面で、（2.8）で与える値に
拡がるように、第１集束レンズ２の励磁用電源７の励磁
電流を調節すれば、 （rP1＋rP2）/Q＝rP1/Z1 ・・・（2.11） ∴ Z1＝rP1・Q/（rP1＋rP2） ・・・（2.12） したがって、第１集束レンズ２、第２集束レンズ３、対
物レンズ５の焦点距離fCL1、fCL2、fOLは、以上から、 fCL1＝PZ1/（Ｐ＋Z1） ・（2.13） として求められる。On the other hand, the brightness of the electron gun 1 is β, and the size of its virtual light source is d 9
Then, the probe current I P on the incident side of the first focusing lens 2
The opening angle α 1 corresponding to Therefore, the beam divergence r P1 on the main surface of the first focusing lens 2 corresponding to I P can be calculated by r P1 = α 1 · P ・ ・ ・ ・ ・ ・ (2,10) . The beam of this radius is used by the first focusing lens 2
Power supply for exciting the first focusing lens 2 so that an image is formed once between the second focusing lens 3 and the second focusing lens 3 and then spreads to a value given by (2.8) on the main surface of the second focusing lens 3. If the excitation current of 7 is adjusted, (r P1 + r P2 ) / Q ＝ r P1 / Z 1・ ・ ・ (2.11) ∴ Z 1 ＝ r P1・ Q / (r P1 ＋ r P2 ) ・ ・ ・ (2.12) Therefore, the focal lengths f CL1 , f CL2 , and f OL of the first focusing lens 2, the second focusing lens 3, and the objective lens 5 are f CL1 = PZ 1 / (P + Z 1 ) · (2.13) Is required as.
すなわち、必要な焦点深度Δｌが与えられた場合、任意
のIPに対して、制御部10は、第１集束レンズ２励磁用電
源７、第２集束レンズ３励磁用電源８の励磁により、第
１集束レンズ２と第２集束レンズ３の焦点距離を（2.1
3）、（2.14）に基づいて調整するようにすればよい。
そして、fOLの値はIPを変えても不変なので、フォーカ
スの再調整や像回転の補正が不要である。また、対物絞
り４の半径rAPを変えることにより、対物レンズ５の焦
点距離fOLの値を変えないで、焦点深度Δｌを変更する
ことができる。したがって、像回転補正をする必要がな
い。さらに、上記のような焦点深度調整モードとは別
に、第１図に点線で示した経路をたどる従来のプローブ
電流を変えると焦点深度も変化する通常のモードになる
ように、制御部10の調整によって、第２集束レンズ３励
磁用電源８、対物レンズ５励磁用電源９により、第２集
束レンズ３と対物レンズ５の焦点距離を変化させるよう
にすると、より多様な観察ができる顕微鏡になる。That is, when the required depth of focus Δl is given, for any I P, the control unit 10, the first focusing lens 2 exciting power supply 7, the excitation of the second condenser lens 3 exciting power source 8, the Set the focal length of the first focusing lens 2 and the second focusing lens 3 to (2.1
It should be adjusted according to 3) and (2.14).
Further, since the value of f OL does not change even if I P is changed, readjustment of focus and correction of image rotation are unnecessary. Further, by changing the radius r AP of the objective diaphragm 4, the focal depth Δl can be changed without changing the value of the focal length f OL of the objective lens 5. Therefore, it is not necessary to correct the image rotation. Further, in addition to the depth of focus adjustment mode as described above, the control unit 10 is adjusted so as to be in a normal mode in which the depth of focus also changes when the conventional probe current that follows the path shown by the dotted line in FIG. 1 is changed. By changing the focal lengths of the second focusing lens 3 and the objective lens 5 by the power source 8 for exciting the second focusing lens 3 and the power source 9 for exciting the objective lens 5, a microscope capable of more diverse observation can be obtained.
本発明の焦点深度調整装置の作用の理解を助けるため
に、第２図にその電子線の経路を従来のものの経路と比
較して示す。電子銃１から出たプローブ電流10-9Aと10
-6A電子ビームの対物絞り４の開口の縁を通る電子線
は、その直径φに応じて（φ70μｍ、φ240μｍ）、図
示のような経路をたどる。図から明らかなように、プロ
ーブ電流が10-9Aから10-6に変わっても、対物絞り４の
径が変わらない限り、開き角α４は変化しない。これに
対して、図の右下に描いてある従来のものにおいては、
プローブ電流が10-9Aから10-6に変わると、対物絞り４
の径を変えなくても（図には、最も焦点深度を深くした
場合（φ70μｍ）と最も焦点深度を浅くした場合（φ24
0μｍ）とを示してある。）、開き角α４が変化してし
まい、焦点深度が変化する。また、本発明においては、
プローブ電流を変えないで（例えば、10-9A）、対物絞
り４の径を変えた場合（φ70μｍからφ240μｍ）、開
き角α４は変化し、焦点深度を容易に変化させることが
できる。In order to help understanding of the operation of the depth-of-focus adjusting device of the present invention, the path of the electron beam is shown in comparison with the path of the conventional one in FIG. Probe current from electron gun 1 10 -9 A and 10
The electron beam passing through the edge of the aperture of the objective aperture 4 of the -6 A electron beam follows the path shown in the figure according to its diameter φ (φ70 μm, φ240 μm). As is apparent from the figure, even if the probe current changes from 10 −9 A to 10 −6 , the opening angle α 4 does not change unless the diameter of the objective diaphragm 4 changes. On the other hand, in the conventional one drawn in the lower right of the figure,
When the probe current changes from 10 -9 A to 10 -6 , the objective aperture 4
Even if the diameter of the lens is not changed (in the figure, when the depth of focus is the deepest (φ70 μm) and when the depth of focus is the shallowest (φ24
0 μm). ), The opening angle α 4 changes, and the depth of focus changes. Further, in the present invention,
When the diameter of the objective aperture 4 is changed (from φ70 μm to φ240 μm) without changing the probe current (for example, 10 −9 A), the opening angle α 4 changes and the depth of focus can be easily changed.
ところで、対物レンズの焦点距離の変化による像回転を
補正する機構を有する装置においては、焦点深度の変更
は、対物絞り４の径を変化させないで（rAPを固定し
て）、その代わりに対物レンズ５の焦点距離fOLを上記
（2.15）に従って変化させることによって行うようにし
てもよい。By the way, in an apparatus having a mechanism for correcting the image rotation due to the change of the focal length of the objective lens, the change of the depth of focus does not change the diameter of the objective diaphragm 4 (fixing r AP ) but the objective instead. Alternatively, the focal length f OL of the lens 5 may be changed according to the above (2.15).
また、先にも述べたように、対物絞り４は、必ずしも第
２集束レンズ３と対物レンズ５の間にある必要はなく、
第２集束レンズ３の上流近傍に位置していてもよい。Further, as described above, the objective diaphragm 4 does not necessarily have to be between the second focusing lens 3 and the objective lens 5, and
It may be located near the upstream side of the second focusing lens 3.
さらに、上記の実施例においては、第１集束レンズ２と
第２集束レンズ３の間に第１集束レンズ２の結像点が存
在しているが、この用件は必ずしも必要なものではな
く、この間に結像点がなくともよく、また、第２集束レ
ンズ３と対物レンズ５の間に第２集束レンズ３の結像点
があるようにしてもよい。Further, in the above embodiment, the image forming point of the first focusing lens 2 exists between the first focusing lens 2 and the second focusing lens 3, but this requirement is not always necessary, There may be no image forming point between them, and there may be an image forming point of the second focusing lens 3 between the second focusing lens 3 and the objective lens 5.
本発明においては、任意のプローブ電流IPに対して、対
物レンズ５の励磁を変えることなしに、焦点深度を一定
に維持できるようにしたので、次のような効果を奏す
る。In the present invention, the depth of focus can be maintained constant without changing the excitation of the objective lens 5 with respect to an arbitrary probe current I P , so that the following effects can be obtained.
（ａ）焦点合わせの再調製が不要になった（EPMA等で
は、分析点の基準点が光学顕微鏡等によって定められて
いるので、再焦点合わせが必要であると、操作が煩雑に
なる）。(A) The readjustment of focusing is not necessary (in EPMA and the like, the reference point of the analysis point is determined by an optical microscope or the like, and thus the operation becomes complicated if refocusing is necessary).
（ｂ）任意のプローブ電流IPに対し、像回転補正が不要
になった。(B) Image rotation correction is not necessary for any probe current I P.
（ｃ）焦点深度は対物絞りの半径rAPで決めることがで
きるので、焦点深度を変更しても、上記（ａ）、（ｂ）
のメリットが生かされる。(C) Since the depth of focus can be determined by the radius r AP of the objective aperture, even if the depth of focus is changed, the above (a) and (b)
The merit of is utilized.
（ｄ）本発明の装置とエネルギー分散型Ｘ線分光器（ED
S）、又は、横型の波長分散型分光器を組み合わせるこ
とにより、凹凸の激しい試料を像のボケやＸ線強度の誤
差なしに分析できる。(D) The apparatus of the present invention and an energy dispersive X-ray spectrometer (ED
By combining S) or a horizontal wavelength dispersive spectroscope, a sample with severe irregularities can be analyzed without image blurring or X-ray intensity error.
（ｅ）従来の、焦点深度は浅いが、プローブ径は細くな
る複数個の絞り径を持つモードを持つものと組み合わせ
ることにより、少数の絞りの個数で広範な焦点深度の調
整ができる（第２図参照）。(E) A wide range of depth of focus can be adjusted with a small number of diaphragms by combining it with a conventional one having a mode with a plurality of diaphragm diameters in which the probe diameter is shallow but the probe diameter becomes small (second See figure).
第１図は本発明の電子顕微鏡等における焦点深度調整装
置の１実施例の構成説明図、第２図は第１図の焦点深度
調整装置の電子線の経路を従来のものの経路と比較して
示す図、第３図はビームの開き角と試料表面の凹凸との
関係を説明するための図である。 1:電子銃（Ｏ）、2:第１集束レンズ（CL1）、3:第２集
束レンズ（CL2）、4:対物絞り（AP）、5:対物レンズ（O
L）、6:試料、7:第１集束レンズ励磁用電源、8:第２集
束レンズ励磁用電源、9:対物レンズ励磁用電源、10:制
御部FIG. 1 is a structural explanatory view of one embodiment of a depth of focus adjustment device in an electron microscope or the like of the present invention, and FIG. 2 compares the electron beam path of the depth of focus adjustment device of FIG. 1 with that of a conventional one. FIG. 3 and FIG. 3 are views for explaining the relationship between the divergence angle of the beam and the unevenness of the sample surface. 1: electron gun (O), 2: first focusing lens (CL1), 3: second focusing lens (CL2), 4: objective aperture (AP), 5: objective lens (O
L), 6: sample, 7: first focusing lens excitation power supply, 8: second focusing lens excitation power supply, 9: objective lens excitation power supply, 10: control unit
Claims (3)
束レンズ、第２集束レンズ、対物絞り、対物レンズを順
に配置し、プローブ電流を任意に変化させた際に、対物
レンズの焦点距離を変更することなしに、設定された焦
点深度を維持するように、第１集束レンズ及び第２集束
レンズの焦点距離を制御する手段を設けたことを特徴と
する電子顕微鏡。1. An electron gun, a first focusing lens, a second focusing lens, an objective diaphragm, and an objective lens are sequentially arranged in a traveling direction of an electron beam, and a focus of the objective lens is obtained when a probe current is arbitrarily changed. An electron microscope comprising means for controlling the focal lengths of the first focusing lens and the second focusing lens so as to maintain the set depth of focus without changing the distance.
り径を変更することによって行うように構成したことを
特徴とする請求項１記載の電子顕微鏡。2. The electron microscope according to claim 1, wherein the setting value of the depth of focus is changed by changing the aperture diameter of the objective aperture.
る通常のモードに切り換え可能に構成したことを特徴と
する請求項１又は２記載の電子顕微鏡。3. The electron microscope according to claim 1, wherein the electron microscope is configured so that it can be switched to a normal mode in which the depth of focus also changes when the probe current is changed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1248794A JPH0760656B2 (en) | 1989-09-25 | 1989-09-25 | electronic microscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1248794A JPH0760656B2 (en) | 1989-09-25 | 1989-09-25 | electronic microscope |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03110742A JPH03110742A (en) | 1991-05-10 |
| JPH0760656B2 true JPH0760656B2 (en) | 1995-06-28 |
Family
ID=17183498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1248794A Expired - Fee Related JPH0760656B2 (en) | 1989-09-25 | 1989-09-25 | electronic microscope |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0760656B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08138600A (en) * | 1994-11-04 | 1996-05-31 | Shimadzu Corp | Charged particle optical system |
| KR100562509B1 (en) * | 2003-12-12 | 2006-03-21 | 삼성전자주식회사 | Apparatus of automated focusing and method for automated focussing using the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01159943A (en) * | 1987-12-15 | 1989-06-22 | Jeol Ltd | Electron beam opening angle control device in electron microscope |
| JPH01236563A (en) * | 1988-03-17 | 1989-09-21 | Jeol Ltd | Multi-purpose opening angle control device of electron microscope |
-
1989
- 1989-09-25 JP JP1248794A patent/JPH0760656B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03110742A (en) | 1991-05-10 |
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