JPS63228559A - Electron microscope - Google Patents

Abstract

PURPOSE:To make such stable photography that is extremely less in sample damage and drift attainable, by masking waiting time until the photography done after focusing optionally settable in accord with a sample characteristic. CONSTITUTION:Waiting until photography started after focusing is optionally selectable. That is to say, an electron beam is moved by the rephotographing coil 6 installed in an intermediate part between an intermediate lens 5 and a projection lens 7 so as to cause an image on a fluorescent screen to be formed in the center. In this state, a preparatory stage for photography of focusing, astigmatic compensation or the like is completed, and afterward the fluorescent screen is opened, inserting a mechanical shutter and interrupting the electron beam, and waiting time until the photography started is made settable as possible for step transfer to, for example, 0-10 seconds. A focusing lens current, controlling an electron beam dose to be irradiated to a sample during the waiting time, is lowered up to the low current value, then it is made to gradually go up to the specified value, thereby controlling an irradiating current to the sample whereby a sudden thermal variation is made so as not to be produced to the sample.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は透過形電子顕微鏡の撮影装置に係り、特に試料
損傷を極力少なくして撮影するのに好適な電子顕微鏡に
おける像撮影装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photographing device for a transmission electron microscope, and more particularly to an image photographing device for an electron microscope suitable for photographing with minimal damage to a sample.

〔従来の技術〕[Conventional technology]

従来の装置は、特許公報昭６１−２０１０８に記載のよ
うに、焦点合せ後ビームブランキングを動作機撮影まで
短い遅延時間を設けていたが、上記時間を任意に設定が
不可であった。又集束レンズの電流値も一度に設定値迄
変化させるようになっていた。In the conventional apparatus, as described in Patent Publication No. 61-20108, a short delay time is provided between beam blanking after focusing and photographing of the operating device, but the above-mentioned time cannot be arbitrarily set. Also, the current value of the focusing lens was changed at once up to a set value.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

上記従来技術は、写真撮影までの待ち時間が一定値に設
定されていて任意に変化させることが出来ない、又試料
に電子線を照射する量をコントロ・−ルする集束レンズ
の電流も一度に撮影時の値に設定するため、写真、撮影
前の試料のドリフトが安定しない状態で撮影をするため
安定した顕微鏡像が得られにくい心配があった。In the conventional technology described above, the waiting time until photographing is set to a fixed value and cannot be changed arbitrarily, and the current of the focusing lens that controls the amount of electron beam irradiated onto the sample is also set at a fixed value. Since the values are set at the time of photography, there was a concern that it would be difficult to obtain stable microscopic images because the drift of the sample before photography was unstable.

本発明の目的は上記試料ドリフトを極力少なくして、安
定した電子顕微鏡像を得ることにある。An object of the present invention is to reduce the sample drift as much as possible to obtain a stable electron microscope image.

〔問題点を解決するための手段〕[Means for solving problems]

上記目的は、焦点合せ後写真撮影までの待ち時間を試料
の特質に合せて任意に設定可能とすること、および、写
真撮影迄に集束レンズ電流を焦点合せ時の値から一度低
い電流値まで落し写真撮影時の条件に徐々に上昇する如
くし、任意に設定することにより達成される。The above purpose is to make it possible to set the waiting time after focusing until taking a photograph according to the characteristics of the sample, and to reduce the focusing lens current from the value at focusing to a lower current value before taking a photograph. This can be achieved by arbitrarily setting the value so that it gradually increases to the conditions at the time of photographing.

〔作用〕[Effect]

焦点合せ時は撮影すべき場所から約１０μｍ離れた場所
で実施出来るよう偏向コイルによって電子線を移動する
。この移動によって蛍光板上の像が中心に結像するよう
中間レンズと投射レンズの中間に設けた振り戻しコイル
によって移動させる。The electron beam is moved by a deflection coil so that focusing can be performed at a location approximately 10 μm away from the location to be photographed. This movement causes the image on the fluorescent screen to be focused on the center by a return coil provided between the intermediate lens and the projection lens.

この状態で焦点合せ、非点補正等写真撮影の為の準備段
階を終了させる。この後蛍光板をオープンし機械的シャ
ッターを挿入し電子線を遮断する。In this state, the preparation stage for photographing, such as focusing and astigmatism correction, is completed. After this, the fluorescent screen is opened and a mechanical shutter is inserted to block the electron beam.

写真撮影開始迄の待ち時間を例えば０〜１０秒にステッ
プ切換が可能な如く設定可能とする。上記待ち時間の間
に試料に照射する電子線量を制御する集束レンズ電流を
低い電流値まで落し徐々に規定値まで上昇する如くして
、試料への照射電流をコントロールし試料に急激な熱変
化が生じないようにするため、試料損傷、試料ドリフト
の極めて少ない安定した状態で写真撮影が可能となる。The waiting time until the start of photographing can be set in steps from 0 to 10 seconds, for example. During the above waiting time, the focusing lens current that controls the electron beam irradiated to the sample is reduced to a low current value and gradually increases to the specified value, thereby controlling the irradiation current to the sample and preventing sudden thermal changes in the sample. In order to prevent this from occurring, it is possible to take photographs in a stable state with extremely little sample damage and sample drift.

〔実施例〕〔Example〕

以下、本発明の一実施例を第１図、および第２図により
詳細に説明する。Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

第１図は試料損傷を極力低減するための一連の動作を示
す電子光学系のレイダイヤグラムを示す。FIG. 1 shows a ray diagram of the electron optical system showing a series of operations to minimize damage to the sample.

視野探し状態は集束レンズ１の励磁を極力弱くして明る
さを少なくし、視野探しを行う。撮影したい視野を蛍光
板中心になるよう試料微動装置で移動する。焦点合せス
イッチを動作させると偏向コイル２が動作し、視野が蛍
光板上で約６０１自動的に倍率リンクして移動する。こ
の後振り戻しコイル６が振り□戻しコ、イ°ル電源１４
によって動作し視野が蛍光板の中心に振り戻される。こ
の状態で焦点合せ、非点補正等写真撮影のための準備を
実施する。In the visual field search state, the excitation of the focusing lens 1 is made as weak as possible to reduce brightness and the visual field is searched. Move the field of view you want to photograph using the sample fine movement device so that it is centered on the fluorescent screen. When the focusing switch is operated, the deflection coil 2 is operated, and the field of view is automatically moved by about 601 degrees on the fluorescent screen with the magnification linked. After this, the return coil 6 swings back, and the coil power supply 14
The field of view is returned to the center of the fluorescent screen. In this state, preparations for photography such as focusing and astigmatism correction are performed.

この時ビームは自動的にスポット状態となり、撮影領域
まで電子線が照射されないようにしている。写真撮影は
蛍光板９を０ｐｅｎにするとシャッター８が電子線を遮
断するため電子線通路に移動する。偏向コイル２．振り
戻しコイル６はそれぞれ設定された値に自動的に励磁が
変化する。集束レンズの電流は任意に設定して規定値に
達する様にステップ状あるいは直線的に変化させること
が出来る。写真撮影までの待ち時間１１も試料に合せて
最適となるよう例えば１０秒迄を任意に切換えて選択出
来るようタイマー１３で設定可能である。At this time, the beam automatically enters a spot state to prevent the electron beam from irradiating the imaging area. For photographing, when the fluorescent screen 9 is set to 0 pen, the shutter 8 moves to the electron beam path to block the electron beam. Deflection coil 2. The excitation of the return coils 6 is automatically changed to the respective set values. The current of the focusing lens can be arbitrarily set and changed stepwise or linearly so as to reach a specified value. The waiting time 11 until photographing can also be set by a timer 13 so that it can be arbitrarily selected from, for example, up to 10 seconds to suit the sample.

撮影時間し２は通常３〜５秒であり露出は適正となった
時点で自動的にシャッター８が動作し撮影が終了する。The photographing time 2 is normally 3 to 5 seconds, and when the exposure becomes appropriate, the shutter 8 is automatically operated and the photographing is completed.

これらの動作に関するタイムチャートを第２図に示す。A time chart regarding these operations is shown in FIG.

実線はそれぞれのコイル、レンズの電流変化を示すと共
に、蛍光板、およびシャッターのＯＮ、ＯＦＦの状態を
示す。撮影終了後は焦点合せの位置に自動的に戻り１次
の撮影の準備状態となる。スルーフォーカスによる連続
撮影も行うことが出来る。The solid lines indicate current changes in each coil and lens, as well as the ON and OFF states of the fluorescent screen and shutter. After photographing is completed, the lens automatically returns to the focusing position and becomes ready for the first photographing. Continuous shooting using through focus is also possible.

〔発明の効果〕〔Effect of the invention〕

本発明によれば、焦点合せ後の撮影までの待ち時間を、
試料に合せて任意に設定可能であること。According to the present invention, the waiting time until photographing after focusing is
It should be possible to set it arbitrarily according to the sample.

待ち時間の間に試料に電子線を照射する量をコントロー
ルする集束レンズ励磁電流を写真撮影時の設定電流値ま
で、徐々にステップ状に上昇するようにしているため、
試料への急激な電子線照射を防ぐことが出来るので、試
料の熱ドリフトおよび熱損傷をより少なくすることが可
能となった。実際に試料ドリフトによる像撮影のミスを
無くすことが出来た。又上記した如く、待ち時間をある
時間内で任意に設定することが出来るため、種々の試料
に対して本システムの効果を応用可能となり。During the waiting time, the focusing lens excitation current, which controls the amount of electron beam irradiation on the sample, is gradually increased in steps up to the current value set at the time of photography.
Since rapid electron beam irradiation to the sample can be prevented, thermal drift and thermal damage to the sample can be further reduced. In fact, we were able to eliminate errors in image capture due to sample drift. Furthermore, as mentioned above, since the waiting time can be arbitrarily set within a certain period of time, the effects of this system can be applied to various samples.

本発明の効果は顕著である。The effects of the present invention are remarkable.

【図面の簡単な説明】 第１図は本発明の一実施例を説明する電子光学系のレイ
ダイヤグラ・ムを示す図、第２図は本発明の動作を示す
タイムチャートを示す図である。 １・・・集束レンズ、２・・・偏向コイル、３・・・試
料、４・・・対物レンズ、５・・・中間レンズ、６・・
・振り戻しコイル、７・・・投射レンズ、８・・・シャ
ッター、９・・・蛍光板、１ｏ・・・フィルム、１１・
・・集束レンズ電源、１２・・・偏向コイル電源、１３
・・・タイマー、１４・・・振り戻しコイル、１５・・
・シャッター駆動電源。 １６・・・蛍光板位置検出、１７・・・フィルムフィー
ド機構。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a ray diagram of an electron optical system for explaining an embodiment of the present invention, and FIG. 2 is a diagram showing a time chart showing the operation of the present invention. DESCRIPTION OF SYMBOLS 1... Focusing lens, 2... Deflection coil, 3... Sample, 4... Objective lens, 5... Intermediate lens, 6...
・Return coil, 7... Projection lens, 8... Shutter, 9... Fluorescent screen, 1o... Film, 11.
... Focusing lens power supply, 12 ... Deflection coil power supply, 13
...Timer, 14...Rewind coil, 15...
・Shutter drive power supply. 16... Fluorescent screen position detection, 17... Film feed mechanism.

Claims (1)

【特許請求の範囲】 １、電子源から射出した電子線を集束させ試料に照射す
る集束レンズと試料への電子線照射位置をシフトさせる
偏向手段と、上記シフトした電子顕微鏡像を蛍光板中心
に振り戻す為のコイルと電子顕微鏡像を撮影するための
機能を備えた装置において、焦点合せ後写真撮影開始ま
での待ち時間を任意に選択可能としたことを特徴とする
電子顕微鏡。 ２、特許請求の範囲第１項において、前記写真撮影開始
までの待ち時間の間に試料に照射する電子線量を写真撮
影時の条件まで任意のステップ状又は連続的に上昇させ
ることを特徴とする電子顕微鏡。[Claims] 1. A focusing lens that focuses the electron beam emitted from the electron source and irradiates it onto the sample, a deflection means that shifts the position of the electron beam irradiation onto the sample, and a deflection means that shifts the shifted electron microscope image to the center of the fluorescent screen. An electron microscope characterized in that, in an apparatus equipped with a coil for returning the image and a function for taking an electron microscope image, the waiting time after focusing until the start of photographing can be arbitrarily selected. 2. According to claim 1, the electron beam dose irradiated to the sample is increased in arbitrary steps or continuously to the conditions at the time of photography during the waiting time until the start of photography. electronic microscope.