JP2008198471A - Charged particle beam device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charged particle beam device in which a secondary electron signal can be carried out stably and a secondary electron signal of a desired energy can be detected without depending on the kind and condition of observation condition. <P>SOLUTION: The charged particle beam device is provided with an accelerating and focusing lens system for accelerate and focusing electron beam from an electron gun, a slowing down and focusing lens system for slowing down the accelerated and focused electron beam and focusing on a testpiece 3, a scanning coil 4 for scanning on the testpiece 3 by the electron beam, a collection electrode 24 which changes an advancing direction of a secondary electron beam which is accelerated and focused by the slowing down and focusing lens system and is slowed down and focused by the accelerating and focusing lens system, a first dispersing electrode 25 and a second dispersing electrode 26 which change the advancing direction of the secondary electron bean in accordance with energy, a secondary electron beam detecting unit 29 for detecting the secondary electron beam and a display unit 12 for displaying a secondary electron beam image of the testpiece 3 based on the detected secondary electron beam. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は試料からの荷電粒子ビームを検出する機構を備えた荷電粒子ビーム装置に関する。   The present invention relates to a charged particle beam apparatus having a mechanism for detecting a charged particle beam from a sample.

近年、半導体集積回路では回路パターンの微細化が一層進んでいる。これらの回路パターンを検査するために、低加速電圧で高分解能の荷電粒子ビーム装置である走査型電子顕微鏡（Scanning Electron Microscope）が用いられている。   In recent years, circuit patterns have been further miniaturized in semiconductor integrated circuits. In order to inspect these circuit patterns, a scanning electron microscope (Scanning Electron Microscope), which is a charged particle beam device with a low acceleration voltage and a high resolution, is used.

この様な走査型電子顕微鏡の中には、例えば、一次電子ビームを加速場でエネルギーを高く維持することにより色収差の影響を低減した状態で合焦点制御し、減速場で試料に入射する一次電子ビームのエネルギーを小さなものにして、低加速電圧で高分解能の試料観察を行うものがある。
図１はこの様な走査型電子顕微鏡の一概略例を示す図である。 In such a scanning electron microscope, for example, the primary electron beam is controlled in focus in a state in which the influence of chromatic aberration is reduced by maintaining high energy in the acceleration field, and the primary electrons incident on the sample in the deceleration field. There is a technique for observing a sample with a low acceleration voltage and a high resolution by reducing the beam energy.
FIG. 1 is a diagram showing a schematic example of such a scanning electron microscope.

図中１は電子銃（図示せず）から放出された電子ビーム（一次電子ビーム）、２は該一次電子ビームを試料３上に集束させるための磁界を形成する磁界レンズ、４は前記一次電子ビーム１で前記試料３上をそれぞれＸ方向，Ｙ方向に走査するための偏向場を形成する走査コイル、５は前記走査コイル４と前記磁界レンズ２に沿って設けら前記一次電子ビーム１を前記試料方向に加速させる電界を形成する円筒型の加速電極、６は該加速された一次電子ビーム１を試料直前で減速させる減速場を形成する減速電極、７は前記試料３を載置する試料ステージで、該ステージを傾斜する傾斜手段（図示せず）を備えている。   In the figure, 1 is an electron beam (primary electron beam) emitted from an electron gun (not shown), 2 is a magnetic lens that forms a magnetic field for focusing the primary electron beam on the sample 3, and 4 is the primary electron. A scanning coil 5 for forming a deflection field for scanning the sample 3 in the X direction and the Y direction with the beam 1 is provided along the scanning coil 4 and the magnetic lens 2, and the primary electron beam 1 is applied to the scanning coil 4. A cylindrical acceleration electrode that forms an electric field that accelerates in the direction of the sample, 6 is a deceleration electrode that forms a deceleration field that decelerates the accelerated primary electron beam 1 immediately before the sample, and 7 is a sample stage on which the sample 3 is placed. And an inclination means (not shown) for inclining the stage.

８は各種指令及び演算等を行う制御装置、９は該制御装置の指令に基づいて走査信号を作成し、該走査信号を前記走査コイル４に送る走査制御装置、１０は前記制御装置８の指令に基づいて前記磁界レンズ２に励磁電流を送る磁界レンズ制御装置である。   8 is a control device that performs various commands and calculations, 9 is a scanning control device that creates a scanning signal based on the command from the control device, and sends the scanning signal to the scanning coil 4. 10 is a command from the control device 8 The magnetic field lens control device sends an exciting current to the magnetic field lens 2 based on the above.

１１は前記一次電子ビーム１による走査により前記試料３から放出された二次電子１２を検出する二次電子検出器で、該二次電子検出器の出力信号は増幅器（図示せず）とＡＤ変換器（図示せず）を介して前記制御装置８に送られる。   Reference numeral 11 denotes a secondary electron detector that detects secondary electrons 12 emitted from the sample 3 by scanning with the primary electron beam 1, and an output signal of the secondary electron detector is an amplifier (not shown) and AD conversion. It is sent to the control device 8 via a device (not shown).

１２は前記制御装置８に送られてきた二次電子信号に基づいて前記試料３上の観察領域に関する二次電子像を表示する表示装置である。   Reference numeral 12 denotes a display device that displays a secondary electron image related to the observation region on the sample 3 based on the secondary electron signal sent to the control device 8.

１３、１４は前記制御装置８の指令に基づいて前記加速電極５、前記減速電極６にそれぞれ正の電圧を印加する可変電源、１５は前記試料３に負の電圧を印加する可変電源である。尚、Ｏは光軸（電子光学の中心軸）である。   Reference numerals 13 and 14 are variable power supplies for applying a positive voltage to the acceleration electrode 5 and the deceleration electrode 6 based on a command from the control device 8, respectively, and 15 is a variable power supply for applying a negative voltage to the sample 3. O is the optical axis (electron optical central axis).

この様な構成の装置において、一次電子ビーム１で試料３上を走査すると、該試料３から二次電子１２が放出され、該二次電子は減速電極６と前記試料３の間に形成される正の電界により、該減速電極の開口部から前記加速電極５内に吸引され、前記磁界レンズ２の磁場によるレンズ作用を受けながら上昇し、二次電子検出器１１に検出される。該二次電子検出器の出力信号（二次電子信号）は増幅器（図示せず）とＡＤ変換器（図示せず）を介して制御装置８に送られ、表示装置１２の表示画面に前記二次電子信号に基づく試料像が表示される。   In the apparatus having such a configuration, when the sample 3 is scanned with the primary electron beam 1, the secondary electrons 12 are emitted from the sample 3, and the secondary electrons are formed between the deceleration electrode 6 and the sample 3. Due to the positive electric field, it is attracted into the acceleration electrode 5 from the opening of the deceleration electrode, rises while receiving the lens action by the magnetic field of the magnetic lens 2, and is detected by the secondary electron detector 11. An output signal (secondary electron signal) of the secondary electron detector is sent to the control device 8 through an amplifier (not shown) and an AD converter (not shown), and the second display is displayed on the display screen of the display device 12. A sample image based on the secondary electron signal is displayed.

国際公開ＷＯ９９/４６７９８号International Publication WO99 / 46798

所で、この様な構成の走査型電子顕微鏡において、取得される画像情報は試料の種類や観察条件に依存して変化する。   In the scanning electron microscope having such a configuration, the acquired image information changes depending on the type of sample and the observation conditions.

例えば、試料表面が電気的絶縁性の高い材料で覆われている場合、得られる画像情報に帯電に基づく像全体を明るくする成分が含まれる。   For example, when the sample surface is covered with a material having high electrical insulation, the obtained image information includes a component that brightens the entire image based on charging.

図２に示すように一次電子ビームに対する加速電圧が試料３からの二次電子発生効率が１より小さい電圧の範囲の場合、前記試料３の電子ビーム照射部分は負に帯電し、該部分の表面電位が、前記試料のその他の部分（電子ビーム非照射部分）と比較して、数Ｖ（ボルト）程度低くなる。これにより、前記試料３から放出される二次電子に含まれる１ｅＶ〜３ｅＶの低エネルギー成分は前記試料３に引き戻されることなく、二次電子検出器１１に取得され画像情報が劣化（前記像全体を明るく）する。   As shown in FIG. 2, when the acceleration voltage for the primary electron beam is in a voltage range where the secondary electron generation efficiency from the sample 3 is less than 1, the electron beam irradiated portion of the sample 3 is negatively charged, and the surface of the portion The potential is lower by about several V (volts) than the other part of the sample (electron beam non-irradiated part). Thereby, the low energy component of 1 eV to 3 eV included in the secondary electrons emitted from the sample 3 is acquired by the secondary electron detector 11 without being pulled back to the sample 3, and the image information is deteriorated (the entire image). Brighten).

又、例えば、磁界レンズ２、加速電極５及び減速電極６から成る対物系レンズにより形成される電磁界が変化すると（試料観察条件の変化の一例）、二次電子１２の集束条件が変化し、これにより、二次電子検出器１１にて取得される二次電子量が低下し、該二次電子信号に基づく画像情報が劣化する。   For example, when the electromagnetic field formed by the objective lens composed of the magnetic lens 2, the acceleration electrode 5, and the deceleration electrode 6 changes (an example of a change in sample observation conditions), the focusing condition of the secondary electrons 12 changes. Thereby, the amount of secondary electrons acquired by the secondary electron detector 11 is reduced, and the image information based on the secondary electron signal is deteriorated.

又、例えば、入射する一次電子ビーム１に対して試料３を傾斜させて該試料の観察を行う場合（試料観察条件の変化の他の例）、図３に示す様に、減速電極６と前記試料３間から漏れる電界（漏洩電界）の形状が変形し（光軸Ｏに対して非対称な形状となる）、該漏洩電界により、前記試料３から放出された二次電子の軌道が１２´に示す様に曲げられ、その結果、前記二次電子検出器１１に取得される二次電子の量が低下し、該二次電子信号に基づく画像情報が劣化する。   For example, when the sample 3 is tilted with respect to the incident primary electron beam 1 and the sample is observed (another example of changes in the sample observation conditions), as shown in FIG. The shape of the electric field (leakage electric field) leaking from between the samples 3 is deformed (becomes asymmetric with respect to the optical axis O), and the trajectory of the secondary electrons emitted from the sample 3 becomes 12 'due to the leakage electric field. As a result, the amount of secondary electrons acquired by the secondary electron detector 11 is reduced, and image information based on the secondary electron signal is deteriorated.

本発明はこの様な問題を解決するために成されたもので、試料の種類や観察条件に依存せずに、安定した良好な二次電子信号を検出したり、或いは、所望のエネルギー帯の二次電子信号を検出することが出来る新規な荷電粒子ビーム装置を提供することを目的とする。   The present invention has been made to solve such problems, and can detect a stable and good secondary electron signal without depending on the type of sample and the observation conditions, or can detect a desired energy band. An object of the present invention is to provide a novel charged particle beam apparatus capable of detecting a secondary electron signal.

本発明の荷電粒子ビーム装置は、荷電粒子ビーム源、該荷電粒子ビーム源からの荷電粒子ビームを加速及び集束する加速集束レンズ系、該加速及び集束された荷電粒子ビームを減速して試料上に集束する減速集束レンズ系、該荷電粒子ビームで前記試料上を走査させるための走査レンズ系、前記減速集束レンズ系で加速及び集束され、前記加速集束レンズ系で減速及び集束された二次荷電粒子ビームの進行方向を変える第１方向変更レンズ系、該方向変更レンズ系により入って来る二次荷電粒子ビームをエネルギーに応じて進行方向を変える第２方向変更レンズ系、該第２方向変更レンズ系からの二次荷電粒子ビームを検出する二次荷電粒子ビーム検出器、及び、該検出された二次荷電粒子ビームに基づいて前記試料の二次荷電粒子ビーム像を表示する表示装置を備えている。   The charged particle beam apparatus of the present invention includes a charged particle beam source, an acceleration focusing lens system for accelerating and focusing the charged particle beam from the charged particle beam source, and decelerating the accelerated and focused charged particle beam onto a sample. A decelerating focusing lens system for focusing, a scanning lens system for scanning the sample with the charged particle beam, and a secondary charged particle accelerated and focused by the decelerating focusing lens system and decelerated and focused by the accelerating focusing lens system A first direction changing lens system for changing the traveling direction of the beam, a second direction changing lens system for changing the traveling direction of the secondary charged particle beam entering by the direction changing lens system according to energy, and the second direction changing lens system A secondary charged particle beam detector for detecting a secondary charged particle beam from the sample, and a secondary charged particle beam image of the sample based on the detected secondary charged particle beam And a display device for displaying.

本発明の荷電粒子ビーム装置は、荷電粒子ビーム源、該荷電粒子ビーム源からの荷電粒子ビームを加速及び集束する加速集束レンズ系、該加速及び集束された荷電粒子ビームを減速して試料上に集束する減速集束レンズ系、該荷電粒子ビームで前記試料上を走査させるための走査レンズ系、前記減速集束レンズ系で加速及び集束され、前記加速集束レンズ系で減速及び集束された二次荷電粒子ビームの進行方向を変える第１方向変更レンズ系、該方向変更レンズ系により入って来る二次荷電粒子ビームを前記第１方向変更レンズ系とでエネルギーに応じて進行方向を変える第２方向変更レンズ系、該第２方向変更レンズ系からの二次荷電粒子ビームを検出する二次荷電粒子ビーム検出器、及び、該検出された二次荷電粒子ビームに基づいて前記試料の二次荷電粒子ビーム像を表示する表示装置を備えている。   The charged particle beam apparatus of the present invention includes a charged particle beam source, an acceleration focusing lens system for accelerating and focusing the charged particle beam from the charged particle beam source, and decelerating the accelerated and focused charged particle beam onto a sample. A decelerating focusing lens system for focusing, a scanning lens system for scanning the sample with the charged particle beam, and a secondary charged particle accelerated and focused by the decelerating focusing lens system and decelerated and focused by the accelerating focusing lens system A first direction changing lens system that changes the traveling direction of the beam, and a second direction changing lens that changes the traveling direction of the secondary charged particle beam that enters from the direction changing lens system according to energy with the first direction changing lens system A secondary charged particle beam detector for detecting a secondary charged particle beam from the second direction-changing lens system, and a front based on the detected secondary charged particle beam And a display device for displaying the secondary charged particle beam image of the sample.

本発明によれば、試料の種類や観察条件に依存せずに、安定に二次電子信号を検出したり、或いは、所望のエネルギー帯の二次電子信号を検出することが出来る。 According to the present invention, a secondary electron signal can be detected stably or a secondary electron signal in a desired energy band can be detected without depending on the type of sample and observation conditions.

以下に添付図面を参照して本発明の実施の形態を詳細に説明する。   Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

図４は本発明の荷電粒子ビーム装置の一例である走査型電子顕微鏡の一概略例を示している。尚、図４において、前記図１にて使用した記号と同一記号を付したものは同一構成要素を示す。   FIG. 4 shows a schematic example of a scanning electron microscope which is an example of the charged particle beam apparatus of the present invention. In FIG. 4, the same reference numerals as those used in FIG. 1 denote the same components.

図４において、２１は電子銃（図示せず）からの一次電子ビームの量を所定の電子量に制限する制限絞り、２２は該制限絞りの鉛直下方に配置され、前記一次電子ビームの開き角を制御する開き角制御レンズである。   In FIG. 4, 21 is a limiting aperture for limiting the amount of primary electron beam from an electron gun (not shown) to a predetermined amount of electrons, 22 is arranged vertically below the limiting aperture, and the opening angle of the primary electron beam Is an opening angle control lens for controlling the angle.

２３は前記開き角制御レンズ２２の鉛直下方に配置され、中央に円形の開口部を有する、例えば、漏斗状の筒体から成る基準電位電極、２４は該基準電位電極の鉛直下方に配置され、試料３からの二次電子を一次電子ビームの軌道軸外に集束及び発散させる収集電極である。   23 is arranged vertically below the opening angle control lens 22 and has a circular opening at the center, for example, a reference potential electrode made of a funnel-shaped cylinder, and 24 is arranged vertically below the reference potential electrode, This is a collection electrode that focuses and diverges secondary electrons from the sample 3 outside the orbital axis of the primary electron beam.

２５、２６は、それぞれ、前記基準電位電極２３と前記収集電極２４との間に互いに接触しないように空間を有して対向配置され、前記収集電極２４によって集束及び発散された二次電子をエネルギー分散するための分散作用を成す第１分散電極、第２分散電極で、共にドーナツ形状を成している。前記第１分散電極２５は、前記試料３に対向している面が前記電子銃側に凹状に湾曲しており、前記第２分散電極２６は前記電子銃側に対向している面が前記試料３側に凹状に湾曲しているので、該両分散電極を全体から見ると、両サイドに大きな隙間を有し、内部に大きな空間を有する円環状体を成している。   25 and 26 are opposed to each other with a space between the reference potential electrode 23 and the collecting electrode 24 so as not to contact each other, and the secondary electrons focused and emitted by the collecting electrode 24 are energized. The first dispersion electrode and the second dispersion electrode that perform the dispersion action for dispersing both form a donut shape. The surface of the first dispersion electrode 25 facing the sample 3 is curved concavely toward the electron gun side, and the surface of the second dispersion electrode 26 facing the electron gun side is the sample. Since it is curved in a concave shape on the 3 side, when viewed from the whole, the two dispersed electrodes form an annular body having a large gap on both sides and a large space inside.

２７は前記収集電極２４の鉛直下方に配置され、中央が円形の開口部を有したすり鉢形状をした第１加速電極、２８は加速電極５の上端に固定された中央が円形の開口部を有したすり鉢形状をした第２加速電極である。   27 is a first accelerating electrode having a mortar shape that is arranged vertically below the collecting electrode 24 and has a circular opening at the center, and 28 has a circular opening at the center fixed to the upper end of the accelerating electrode 5. This is a second accelerating electrode having a mortar shape.

２９は前記第１分散電極２５の凹状湾曲面と前記第２分散電極２６の凹状湾曲面との間に形成される空間部を通過する二次電子を検出する二次電子検出器で、該二次電子検出器の出力（二次電子信号）は増幅器（図示せず）とＡＤ変換器（図示せず）を介して制御装置８に送られる。   29 is a secondary electron detector for detecting secondary electrons passing through a space formed between the concave curved surface of the first dispersion electrode 25 and the concave curved surface of the second dispersion electrode 26. The output of the secondary electron detector (secondary electron signal) is sent to the control device 8 via an amplifier (not shown) and an AD converter (not shown).

３０は前記制御装置８の指令に基づいて前記第１分散電極２５と前記第２分散電極２６に電圧を印加する分散電極制御装置である。   Reference numeral 30 denotes a distributed electrode control device that applies a voltage to the first distributed electrode 25 and the second distributed electrode 26 based on a command from the control device 8.

３２は前記制御装置８の指令に基づいてレンズ制御信号を前記開き角制御レンズ２２に送る開き角レンズ制御装置である。   An open angle lens control device 32 sends a lens control signal to the open angle control lens 22 based on a command from the control device 8.

３３は前記制御装置８の指令に基づいて前記基準電位電極２３に電圧を印加する可変電源、３４は前記制御装置８の指令に基づいて前記収集電極２４に電圧を印加する可変電源、３５は前記制御装置８の指令に基づいて前記第１加速電極３０に電圧を印加する可変電源である。   33 is a variable power source that applies a voltage to the reference potential electrode 23 based on a command from the control device 8, 34 is a variable power source that applies a voltage to the collecting electrode 24 based on a command from the control device 8, and 35 is the This is a variable power source that applies a voltage to the first acceleration electrode 30 based on a command from the control device 8.

この様に構成された走査型電子顕微鏡において、電子銃から放出され、前記制限絞り２１及び開き角制御レンズ２２を通過した一次電子ビームは、１´に示す様に、前記基準電位電極２３、前記第１加速電極２７及び前記第２加速電極２８から形成される加速場レンズ３６により加速及び集束され（点Ａに集束する）、前記加速電極５，減速電極６及び試料３から形成される減速場レンズ系により形成される減速場レンズ２０により減速され、該減速場レンズに前記磁界レンズ２が形成する磁場から成る電磁界レンズにより前記試料３上に集束する。   In the scanning electron microscope configured in this way, the primary electron beam emitted from the electron gun and passed through the limiting diaphragm 21 and the opening angle control lens 22 is the reference potential electrode 23, the A deceleration field formed from the acceleration electrode 5, the deceleration electrode 6, and the sample 3 is accelerated and focused (focused to a point A) by an acceleration field lens 36 formed from the first acceleration electrode 27 and the second acceleration electrode 28. The lens is decelerated by a deceleration field lens 20 formed by a lens system, and is focused on the sample 3 by an electromagnetic field lens composed of a magnetic field formed by the magnetic field lens 2 on the deceleration field lens.

この際、前記制御装置８からの指令に基づいて、前記走査制御装置９は前記走査コイル４に走査信号を供給するので、前記一次電子ビーム１´は前記試料３上を走査する。   At this time, the scanning control device 9 supplies a scanning signal to the scanning coil 4 based on a command from the control device 8, so that the primary electron beam 1 ′ scans the sample 3.

該一次電子ビーム１´の照射により、前記試料３から二次電子が放出され、該二次電子は前記加速電極５、前記減速電極６及び前記試料３から形成される加速場レンズ２０（前記一次電子ビームに対して減速場として作用する前記減速場レンズ２０は二次電子から見ると加速場レンズとして作用する）により加速されて前記減速電極６の開口部に吸引され、更に、該加速場レンズ２０と前記磁界レンズ２の磁場とで形成される電磁界により集束されて、図５において３７に示す様に、前記加速電極５内を光軸Ｏに沿って上昇する。   By irradiation of the primary electron beam 1 ′, secondary electrons are emitted from the sample 3, and the secondary electrons are emitted from the acceleration electrode 5, the deceleration electrode 6, and the acceleration field lens 20 formed from the sample 3 (the primary field). The deceleration field lens 20 acting as a deceleration field with respect to the electron beam is accelerated by a secondary electron) and sucked into the opening of the deceleration electrode 6, and further the acceleration field lens 20 and the electromagnetic field formed by the magnetic field of the magnetic lens 2, and ascends along the optical axis O in the acceleration electrode 5 as indicated by 37 in FIG.

この二次電子は前記基準電位電極２３、前記第１加速電極２７及び前記第２加速電極２８から形成される減速場レンズ３６（前記一次電子ビームに対して加速場として作用する前記加速場レンズ３６は二次電子に対しては減速場レンズとして作用する）により減速され、点Ｂに集束する。尚、この集束点は、前記基準電位電極２３に印加する電圧によってコントロールすることが出来るので、前記集束点が固定されるように、前記可変電源３３からの印加電圧を調整するようにしている。   The secondary electrons are a deceleration field lens 36 formed from the reference potential electrode 23, the first acceleration electrode 27, and the second acceleration electrode 28 (the acceleration field lens 36 acting as an acceleration field for the primary electron beam). Acts as a deceleration field lens for secondary electrons) and converges to point B. The focusing point can be controlled by the voltage applied to the reference potential electrode 23. Therefore, the applied voltage from the variable power source 33 is adjusted so that the focusing point is fixed.

この様に集束する位置が固定された二次電子は前記第１分散電極２５と第２分散電極２６との間の空間方向に導かれる様に、前記収集電極２４によって一次電子ビームの軌道軸外に集束・発散される。尚、この集束・発散の程度は可変電源３４から収集電極２４へ印加する電圧によってコントロールすることが出来る。この際、前記二次電子の開き角θは前記基準電位電極２３と前記第１加速電極２７とで形成される電界によって決まるので、出来るだけ前記空間に二次電子が導かれる様な電圧が、前記可変電源３３から前記基準電位電極２３に、前記可変電源３５から前記第１加速電極２７に印加される。   The secondary electrons whose focusing position is fixed in this way are guided by the collecting electrode 24 in the spatial direction between the first dispersion electrode 25 and the second dispersion electrode 26 so that the primary electron beam is off the orbit axis. Focused and diverged. The degree of convergence / divergence can be controlled by the voltage applied from the variable power source 34 to the collecting electrode 24. At this time, since the opening angle θ of the secondary electrons is determined by the electric field formed by the reference potential electrode 23 and the first acceleration electrode 27, a voltage that leads the secondary electrons to the space as much as possible. The variable power supply 33 is applied to the reference potential electrode 23, and the variable power supply 35 is applied to the first acceleration electrode 27.

さて、前記試料３からの二次電子を前記二次電子検出器２９に検出する際、エネルギーに選別することなく検出する場合には、例えば、前記分散電極制御装置３０から前記第１分散電極２５と前記第２分散電極２６に、二次電子エネルギーの平均的エネルギーに相当する負の電位を印加する。   When the secondary electrons from the sample 3 are detected by the secondary electron detector 29 without being sorted into energy, for example, from the distributed electrode control device 30 to the first distributed electrode 25. A negative potential corresponding to the average energy of secondary electron energy is applied to the second dispersion electrode 26.

すると、前記二次電子中、前記収集電極２４に近い軌道を飛行するエネルギーの低い二次電子は、前記第２分散電極２６で反射され、図５において３７ａに示す様に、前記二次電子検出器２９に導かれ、前記二次電子中、前記第１分散電極２５に近い軌道を飛行するエネルギーの高い二次電子は、該第１分散電極で反射されて飛行し、図５において３７ｂに示す様に、前記二次電子検出器２９に導かれる。   Then, the secondary electrons having low energy flying in the orbit close to the collecting electrode 24 in the secondary electrons are reflected by the second dispersion electrode 26, and as shown in 37a in FIG. In the secondary electrons, secondary electrons having high energy flying in the orbit close to the first dispersion electrode 25 are reflected by the first dispersion electrode and fly, as shown in 37b in FIG. Similarly, the secondary electron detector 29 is guided.

該二次電子検出器の出力（二次電子信号）は増幅器（図示せず）とＡＤ変換器を介して前記制御装置８に送られ、表示装置１２の表示画面に前記試料３の二次電子像が表示される。   The output (secondary electron signal) of the secondary electron detector is sent to the control device 8 via an amplifier (not shown) and an AD converter, and the secondary electrons of the sample 3 are displayed on the display screen of the display device 12. An image is displayed.

次に、例えば、二次電子像全体を明るくする成分である試料帯電域から放出される低エネルギーの二次電子をカットし、高エネルギー二次電子を選別して検出する場合には次の様に操作する。   Next, for example, when cutting low-energy secondary electrons emitted from the charged region of the sample, which is a component that brightens the entire secondary electron image, and selecting and detecting high-energy secondary electrons: To operate.

前記制御装置８の指令に基づいて前記分散電極制御装置３０から、前記第１分散電極２５には前記と同様に負の電位が印加され、第２分散電極２６には、例えば零電位或いは正電位が印加される。   Based on the command of the control device 8, a negative potential is applied to the first dispersion electrode 25 from the dispersion electrode control device 30 as described above, and a zero potential or a positive potential is applied to the second dispersion electrode 26, for example. Is applied.

すると、前記二次電子中、前記収集電極２４に近い軌道を飛行するエネルギーの低い二次電子は、図６において３７ａ´に示す様に、前記第２分散電極２６に引きつけられ、前記二次電子検出器２９に達せず、前記二次電子中、前記第１分散電極２５に近い軌道を飛行するエネルギーの高い二次電子は、該第１分散電極で反射されて飛行し、図６において３７ｂ´に示す様に、前記二次電子検出器２９に導かれる。   Then, the secondary electrons having low energy flying in the orbit close to the collecting electrode 24 among the secondary electrons are attracted to the second dispersive electrode 26 as indicated by 37a ′ in FIG. High energy secondary electrons that do not reach the detector 29 and fly in an orbit close to the first dispersion electrode 25 in the secondary electrons are reflected by the first dispersion electrode and fly, and in FIG. As shown in FIG. 4, the secondary electron detector 29 is guided.

従って、前記二次電子検出器２９にはエネルギーの高い二次電子のみが検出され、前記表示装置１２の表示画面には、前記試料３上の観察領域中、帯電域から発生した低エネルギーの二次電子に基づく画像情報が除去された、高エネルギーの二次電子に基づく二次電子像が表示される。   Therefore, only the secondary electrons with high energy are detected by the secondary electron detector 29, and the low energy energy generated from the charged region in the observation region on the sample 3 is displayed on the display screen of the display device 12. A secondary electron image based on the high energy secondary electrons from which image information based on the secondary electrons has been removed is displayed.

逆に、高エネルギーの二次電子をカットし、低エネルギーの二次電子を選別して検出する場合には次の様に操作する。   Conversely, when high energy secondary electrons are cut and low energy secondary electrons are selected and detected, the following operation is performed.

前記制御装置８の指令に基づいて前記分散電極制御装置３０から、前記第１分散電極２５には零又は正の電位が印加され、第２分散電極２６には負の電位が印加される。   Based on a command from the control device 8, a zero or positive potential is applied to the first dispersion electrode 25 from the dispersion electrode control device 30, and a negative potential is applied to the second dispersion electrode 26.

すると、前記二次電子中、前記収集電極２４に近い軌道を飛行するエネルギーの低い二次電子は、該第２分散電極２６で反射されて飛行し、図７において３７ａ´´に示す様に、前記二次電子検出器２９に導かれ、前記二次電子中、前記第１分散電極２５に近い軌道を飛行するエネルギーの高い二次電子は、図７において３７ｂ´´に示す様に、前記第１分散電極２５に引きつけられ、前記二次電子検出器２９に達しない。   Then, the secondary electrons with low energy flying in the orbit close to the collecting electrode 24 in the secondary electrons are reflected by the second dispersion electrode 26 and fly, as shown by 37a '' in FIG. High energy secondary electrons guided to the secondary electron detector 29 and flying in the orbit close to the first dispersive electrode 25 in the secondary electrons, as indicated by 37b ″ in FIG. 1 is attracted to the dispersed electrode 25 and does not reach the secondary electron detector 29.

従って、前記二次電子検出器２９にはエネルギーの低い二次電子のみが検出され、前記表示装置１２の表示画面には、前記試料３上の観察領域中で、高エネルギーの二次電子に基づく画像情報が除去された、いわゆる、帯電域から発生した低エネルギーの二次電子に基づく二次電子像が表示される。   Accordingly, only secondary electrons with low energy are detected by the secondary electron detector 29, and the display screen of the display device 12 is based on secondary electrons with high energy in the observation region on the sample 3. A so-called secondary electron image based on low energy secondary electrons generated from the charged region, from which image information has been removed, is displayed.

次に、試料観察条件が変化した場合の対処について説明する。   Next, how to deal with changes in sample observation conditions will be described.

前記した様に、例えば、前記磁界レンズ２，加速電極５及び減速電極６から成る対物系レンズにより形成される電磁界が変化すると、前記試料３からの二次電子の軌道が、例えば、図８において３８に示す様に、広がって、例えば、前記第２加速電極２８に衝突してしまう。   As described above, for example, when the electromagnetic field formed by the objective lens composed of the magnetic lens 2, the acceleration electrode 5 and the deceleration electrode 6 is changed, the trajectory of the secondary electrons from the sample 3 is, for example, FIG. As shown at 38 in FIG. 3, the film spreads and, for example, collides with the second acceleration electrode 28.

この様な場合、前記減速電極６と加速電極５とが作る電界で前記試料３からの二次電子の放出方向の開き具合をコントロールすることが出来るので、前記可変電源１４から前記減速電極６へ供給される電圧及び／若しくは前記可変電源１３から前記加速電極５へ供給される電圧を調整することにより、前記試料３から放出される二次電子が前記第２加速電極２８の下面に衝突せずに、該第２加速電極の中心孔内を通過する様にし、試料３からの二次電子を効率的に前記二次電子検出器２９に導くことが出来る。   In such a case, since the degree of opening of the secondary electrons from the sample 3 can be controlled by the electric field generated by the deceleration electrode 6 and the acceleration electrode 5, the variable power supply 14 is connected to the deceleration electrode 6. By adjusting the supplied voltage and / or the voltage supplied from the variable power source 13 to the acceleration electrode 5, secondary electrons emitted from the sample 3 do not collide with the lower surface of the second acceleration electrode 28. In addition, the secondary electrons from the sample 3 can be efficiently guided to the secondary electron detector 29 by passing through the center hole of the second acceleration electrode.

又、別の対策として、図９に示す様に、前記第１加速電極２７と第２加速電極２８を取り囲む様に、回転対称レンズである磁界コイル３９を設け、前記制御装置８の指令を受けて作動する磁界コイル制御装置４０から最適な励磁電流が該磁界コイルに供給される様に成す。   As another countermeasure, as shown in FIG. 9, a magnetic field coil 39, which is a rotationally symmetric lens, is provided so as to surround the first acceleration electrode 27 and the second acceleration electrode 28, and a command from the control device 8 is received. Thus, an optimum exciting current is supplied to the magnetic field coil from the magnetic field coil control device 40 which operates.

この様に成せば、前記磁界コイル３９は、前記第１加速電極２７及び前記第２加速電極２８から成るレンズ系により形成される減速場レンズ３６（一次電子に対して加速場レンズとして作用するが、二次電子に対しては減速場レンズとして作用する）近傍に光軸方向に向く磁界を形成する。該磁界は前記一次電子ビームに影響を与えることなく二次電子を集束点Ｂ近傍に集束させるので、前記試料３から放出される二次電子が前記第２加速電極２８の下面に衝突せずに、該第２加速電極の中心孔内を通過する。従って、前記試料３からの二次電子を効率的に前記二次電子検出器２９に導くことが出来る。   In this way, the magnetic field coil 39 acts as a deceleration field lens 36 (which acts as an acceleration field lens for primary electrons) formed by a lens system comprising the first acceleration electrode 27 and the second acceleration electrode 28. It acts as a deceleration field lens for secondary electrons) and forms a magnetic field directed in the optical axis direction in the vicinity. The magnetic field focuses the secondary electrons near the focal point B without affecting the primary electron beam, so that the secondary electrons emitted from the sample 3 do not collide with the lower surface of the second acceleration electrode 28. , Passing through the center hole of the second acceleration electrode. Accordingly, secondary electrons from the sample 3 can be efficiently guided to the secondary electron detector 29.

次に、入射する一次電子ビーム１に対して試料３を傾斜させて該試料の観察を行う場合、減速電極６と前記試料３間からの漏洩電界の形状が変形（電界歪）し、該電界歪により、前記試料３から放出された二次電子の軌道が曲げられ、前記二次電子検出器１１に取得される二次電子の量が低下する点について既に述べた（図３参照）が、図４に示す装置においても試料を傾斜させると同様な軌道変化が発生し、前記試料３からの二次電子が、例えば、前記収集電極２４や第２加速電極２８に衝突し（図１０参照）、前記二次電子検出器２９に取得される二次電子の量が低下する。   Next, when the sample 3 is tilted with respect to the incident primary electron beam 1 and the sample is observed, the shape of the leakage electric field between the deceleration electrode 6 and the sample 3 is deformed (electric field distortion), and the electric field is As described above, the trajectory of the secondary electrons emitted from the sample 3 is bent due to the distortion, and the amount of secondary electrons acquired by the secondary electron detector 11 is reduced (see FIG. 3). In the apparatus shown in FIG. 4, when the sample is tilted, the same orbital change occurs, and the secondary electrons from the sample 3 collide with, for example, the collection electrode 24 and the second acceleration electrode 28 (see FIG. 10). The amount of secondary electrons acquired by the secondary electron detector 29 decreases.

この様な場合、図１１に示す様に、前記減速電極６の近傍に、前記試料３を傾斜させることにより発生する該減速電極と前記試料３の間にからの漏洩電界の歪みを矯正する歪み矯正用電極板４１Ａ，４１Ｂ，４１Ｃ（４１Ｂ，４１Ｃは図示されていない）を配置する。   In such a case, as shown in FIG. 11, distortion that corrects the distortion of the leakage electric field between the deceleration electrode 6 and the sample 3 generated by inclining the sample 3 in the vicinity of the deceleration electrode 6. Correcting electrode plates 41A, 41B and 41C (41B and 41C are not shown) are arranged.

図１２の（ａ）は前記減速電極６と前記歪み矯正用電極板４１Ａ，４１Ｂ，４１Ｃを試料側から見た図であり、図１２の（ｂ）は光軸に垂直な方向から見た図である。   12A is a view of the deceleration electrode 6 and the distortion correcting electrode plates 41A, 41B, and 41C as viewed from the sample side, and FIG. It is.

前記歪み矯正用電極板４１Ａ，４１Ｂ，４１Ｃは、光軸Ｏを含む方向の断面が円錐台形状を成している減速電極６を該減速電極に沿って三方から取り囲む様に光軸Ｏを中心に配置されており、それぞれ扇状の形状を成している。
尚、歪み矯正用電極板は試料傾斜方向の上位置側には設けられていない。これにより、試料をより高傾斜させることが可能である。
前記各三枚の歪み矯正用電極板４１Ａ，４１Ｂ，４１Ｃには、それぞれ、前記制御装置８の指令で作動する可変電源４２ａ，４２ｂ，４２ｃから歪み矯正用制御電圧が印加される様に成っている。 The distortion correcting electrode plates 41A, 41B, 41C are centered on the optical axis O so as to surround the deceleration electrode 6 having a truncated cone shape in a cross section including the optical axis O from three sides along the deceleration electrode. Are arranged in a fan shape.
The strain correction electrode plate is not provided on the upper side of the sample tilt direction. This makes it possible to tilt the sample at a higher angle.
Each of the three distortion correcting electrode plates 41A, 41B, 41C is applied with a distortion correcting control voltage from a variable power source 42a, 42b, 42c operated by a command of the control device 8, respectively. Yes.

而して、前記図１０に示す様に、入射する一次電子ビームに対して前記試料ステージ７を傾けることにより前記試料３を光軸Ｏに対して傾斜させると、前記減速電極６と前記試料３間からの漏洩電界の形状が図１２の（ｂ）の４３に示す様に変形し、光軸Ｏに対して非軸対称なものとなる。   Thus, as shown in FIG. 10, when the sample stage 7 is tilted with respect to the optical axis O by tilting the sample stage 7 with respect to the incident primary electron beam, the deceleration electrode 6 and the sample 3 are tilted. The shape of the leakage electric field from between is deformed as indicated by 43 in FIG. 12B and becomes non-axisymmetric with respect to the optical axis O.

ここで、前記制御装置８の指示に基づいて前記可変電源４２ａ，４２ｂ，４２ｃから前記偏向電極板４１Ａ，４１Ｂ，４１Ｃに、前記漏洩電界が光軸Ｏに対して対称（図１２の（ｂ）の４４に示す）に成る様に、例えば、前記減速電極６に印加している電圧より前記試料に印加している電圧に近い電圧を印加する。   Here, the leakage electric field is symmetric with respect to the optical axis O from the variable power sources 42a, 42b, and 42c to the deflection electrode plates 41A, 41B, and 41C based on an instruction from the control device 8 ((b) of FIG. 12). For example, a voltage closer to the voltage applied to the sample than the voltage applied to the deceleration electrode 6 is applied.

この様に前記漏洩電界が光軸Ｏに対して対象な形状になるように矯正されると、前記試料３から放出された二次電子は、図１１に示す様に、光軸Ｏに沿った軌道となり、前記第２加速電極２８や収集電極２４に衝突することなく前記二次電子検出器２９に効率良く検出される。   When the leakage electric field is corrected so as to have a target shape with respect to the optical axis O in this way, secondary electrons emitted from the sample 3 follow the optical axis O as shown in FIG. It becomes an orbit and is efficiently detected by the secondary electron detector 29 without colliding with the second acceleration electrode 28 or the collection electrode 24.

尚、前記例では、二次電子検出器は１個だけ設けたが、光軸Ｏに対して前記二次電子検出器２９の対向位置に別の二次電子検出器を設け、該２つの二次電子検出器で検出した二次電子の信号に基づいて前記試料３表面の凹凸像を前記表示装置１２の表示画面に表示させるように成しても良い。尚、二次電子検出器を光軸Ｏの軸対称位置に４個以上設けても良い。   In the above example, only one secondary electron detector is provided. However, another secondary electron detector is provided at a position opposite to the secondary electron detector 29 with respect to the optical axis O, and the two secondary electron detectors are provided. An uneven image on the surface of the sample 3 may be displayed on the display screen of the display device 12 based on a secondary electron signal detected by a secondary electron detector. Note that four or more secondary electron detectors may be provided at a position symmetrical with respect to the optical axis O.

又、二次電子検出器の代わりにマイクロチャンネルプレートの如き平板状電子検出器を設けても良い。   In addition, a flat electron detector such as a microchannel plate may be provided instead of the secondary electron detector.

図１３は前記二次電子検出器２９の代わりに平板状電子検出器を設けた場合の一例を示すもので、前記図４にて使用された記号と同一記号が付されたものは同一構成要素である。   FIG. 13 shows an example in which a flat electron detector is provided in place of the secondary electron detector 29, and the same components as those used in FIG. It is.

この例の場合では、前記第２分散電極２６が削除され、該第２分散電極が配置されていた位置に平板状電子検出器４５が配置され、その中心孔内に、鍔部の無い筒状の収集電極２４´が配置される。尚、前記平板状電子検出器４５は増幅器（図示せず）とＡＤ変換器（図示せず）を介して前記制御装置８に接続されている。   In the case of this example, the second dispersion electrode 26 is deleted, a plate-like electron detector 45 is disposed at the position where the second dispersion electrode is disposed, and a cylindrical shape having no flange portion in the center hole thereof. A collecting electrode 24 'is arranged. The flat electron detector 45 is connected to the control device 8 via an amplifier (not shown) and an AD converter (not shown).

而して、該二次電子は前記加速電極５、前記減速電極６及び前記試料３から形成される加速場レンズ２０（一次電子に対して減速場として作用する前記減速場レンズ２０は二次電子に対して加速場レンズとして作用する）により加速されて前記減速電極６の開口部に吸引され、更に、該加速場レンズ２０と前記磁界レンズ２の磁場とで形成される電磁界により集束されて、図５において３７に示す様に、前記加速電極５内を光軸Ｏに沿って上昇する。   Thus, the secondary electrons are the acceleration field lens 20 formed from the acceleration electrode 5, the deceleration electrode 6 and the sample 3 (the deceleration field lens 20 acting as a deceleration field for the primary electrons is a secondary electron). And is attracted to the opening of the decelerating electrode 6 and further focused by an electromagnetic field formed by the acceleration field lens 20 and the magnetic field of the magnetic field lens 2. 5, the acceleration electrode 5 rises along the optical axis O as indicated by 37.

この二次電子は前記基準電位電極２３、前記第１加速電極２７及び前記第２加速電極２８から形成される減速場レンズ３６（一次電子に対して加速場として作用する前記加速場レンズ３６は二次電子に対して減速場レンズとして作用する）により減速され、点Ｂに集束する。   The secondary electrons are a deceleration field lens 36 formed from the reference potential electrode 23, the first acceleration electrode 27, and the second acceleration electrode 28 (the acceleration field lens 36 acting as an acceleration field for the primary electrons is a secondary field). It acts as a deceleration field lens for the secondary electrons) and converges to point B.

該二次電子は前記収集電極２４´によって一次電子ビームの軌道軸外に集束・発散され、前記第１分散電極２５と前記収集電極２４´との間の空間方向に導かれる。   The secondary electrons are focused and diverged out of the orbital axis of the primary electron beam by the collecting electrode 24 ', and are guided in the spatial direction between the first dispersion electrode 25 and the collecting electrode 24'.

さて、前記第１分散電極２５には、前記分散電極制御装置３０から正又は負の電位が、前記収集電極２４´には、前記可変電源３４から、正の電圧が印加されており、前記第１分散電極２５と前記収集電極２４´の形成される電界により、入ってくる二次電子をエネルギー分散させ、結果的に、前記平板状電子検出器４５へ到達する二次電子をエネルギーに関して選別するようにしている。   A positive or negative potential is applied to the first distributed electrode 25 from the distributed electrode control device 30, and a positive voltage is applied to the collection electrode 24 ′ from the variable power source 34. 1 An incoming electric field energy is dispersed by an electric field formed by the dispersion electrode 25 and the collecting electrode 24 ', and as a result, the secondary electrons that reach the plate-shaped electron detector 45 are selected with respect to energy. I am doing so.

例えば、前記第１分散電極２５に負の電位を印加しておけば、前記二次電子中、前記収集電極２４´、に近い軌道を飛行するエネルギーの低い二次電子は、前記収集電極２４´、に引きつけられるので、４６ａに示す様に、前記平板状電子検出器４５の中心孔部分に導かれ、前記二次電子中、前記第１分散電極２５に近い軌道を飛行するエネルギーの高い二次電子は、前記第１分散電極２５で反射され、４６ｂに示す様に、前記平板状電子検出器４５の検出面部分に導かれる。該平板状電子検出器の検出面部分で検出された二次電子の信号は増幅器（図示せず）とＡＤ変換器を介して前記制御装置８に送られるので、表示装置１２の表示画面に前記試料３の二次電子像が表示される。   For example, if a negative potential is applied to the first dispersion electrode 25, secondary electrons having low energy flying in a trajectory close to the collection electrode 24 ′ in the secondary electrons are collected in the collection electrode 24 ′. As shown in 46a, the secondary electron is guided to the central hole portion of the plate-shaped electron detector 45 and has a high energy secondary flying in the secondary electrons in the orbit close to the first dispersive electrode 25. The electrons are reflected by the first dispersion electrode 25 and guided to the detection surface portion of the flat-plate electron detector 45 as shown by 46b. Since the secondary electron signal detected by the detection surface portion of the flat plate electron detector is sent to the control device 8 through an amplifier (not shown) and an AD converter, the display screen of the display device 12 displays the signal. A secondary electron image of the sample 3 is displayed.

尚、前記平板状電子検出器４５として、図１４に示す様に、中央に一次電子ビームや二次電子が通過出来、且つ、前記収集電極２４´が配置される中心孔４５ａを有し、例えば、該中心孔周囲の電子検出面が周囲方向に２分割、放射方向に３分割された構造のものを使用すれば、２分割各部分で検出された二次電子に基づいて試料表面の凸凹情報が得られ、又、一番中側の検出部分４５ｂ、一番外側の検出部分４５ｃ、中側検出面８０ｂ、中間の検出部分４５ｄで、それぞれ異なったエネルギーの二次電子を検出することが出来る。   As shown in FIG. 14, the flat-plate electron detector 45 has a central hole 45a through which a primary electron beam and secondary electrons can pass and a collection electrode 24 'is disposed. If the electron detection surface around the central hole is divided into two parts in the peripheral direction and three parts in the radial direction, unevenness information on the sample surface is obtained based on the secondary electrons detected in each part. Further, secondary electrons having different energies can be detected by the innermost detection portion 45b, the outermost detection portion 45c, the intermediate detection surface 80b, and the intermediate detection portion 45d. .

又、前記例では第１分散電極２５と第２分散電極２６としてドーナツ状のものを使用し、両電極で円環状のエネルギー分散体を形成するようにしたが、例えば、二次電子検出器が１個の場合は、該１個の二次電子検出器だけに二次電子が検出されれば良いので、円環状の分散体でなくても良く、該二次電子検出器の前に、前記円環状のエネルギー分散体を周方向に一部分取り出したようなエネルギー分散体を用いるようにしても良い。   In the above example, the first dispersion electrode 25 and the second dispersion electrode 26 are donut-shaped, and an annular energy dispersion is formed by both electrodes. For example, a secondary electron detector is used. In the case of one, it is only necessary that the secondary electrons be detected only by the one secondary electron detector, and therefore, it may not be an annular dispersion, and before the secondary electron detector, An energy dispersion obtained by partially extracting an annular energy dispersion in the circumferential direction may be used.

又、第１分散電極２５と第２分散電極２６、第１加速電極２７と第２加速電極２８等は、前記例に示す如き形状に限定されないことは言うまでもない。   Needless to say, the first dispersion electrode 25, the second dispersion electrode 26, the first acceleration electrode 27, the second acceleration electrode 28, and the like are not limited to the shapes shown in the above example.

又、図９で示した二次電子を集束点Ｂ近傍に集束させる磁界コイル３９の代わりに、同じ様に、二次電子を集束点Ｂ近傍に集束させる作用をする電界を形成する電極を用いても良い。   Further, instead of the magnetic field coil 39 for focusing the secondary electrons in the vicinity of the focusing point B shown in FIG. 9, similarly, an electrode for forming an electric field that functions to focus the secondary electrons in the vicinity of the focusing point B is used. May be.

又、前記例では、本発明を走査型電子顕微鏡に応用したものを示したが、他の荷電粒子ビーム装置、例えば、集束イオンビーム等にも応用可能である。   In the above example, the present invention is applied to a scanning electron microscope. However, the present invention can be applied to other charged particle beam devices such as a focused ion beam.

又、前記例では試料から発生する二次電子を検出する装置を示したが、試料から発生するイオンを検出する装置にも応用可能であることは言うまでもない。   In the above example, an apparatus for detecting secondary electrons generated from a sample is shown, but it goes without saying that the apparatus can also be applied to an apparatus for detecting ions generated from a sample.

従来の走査型電子顕微鏡の構成及び二次電子の軌道を示す説明図である。It is explanatory drawing which shows the structure of the conventional scanning electron microscope, and the trajectory of a secondary electron. 一次電子ビームの加速電圧に対応した二次電子発生効率の関係を示す説明図であるIt is explanatory drawing which shows the relationship of the secondary electron generation efficiency corresponding to the acceleration voltage of a primary electron beam. 従来の走査型電子顕微鏡の構成における試料を傾斜させた場合の二次電子の軌道を示す説明図である。It is explanatory drawing which shows the track | orbit of a secondary electron at the time of inclining the sample in the structure of the conventional scanning electron microscope. 本発明の走査型電子顕微鏡の全体構成及び一次電子ビームの軌道を示す説明図である。It is explanatory drawing which shows the whole structure of the scanning electron microscope of this invention, and the track | orbit of a primary electron beam. 本発明の走査型電子顕微鏡の構成において二次電子の軌道を示す説明図である。It is explanatory drawing which shows the orbit of a secondary electron in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において二次電子の軌道を示す説明図である。It is explanatory drawing which shows the orbit of a secondary electron in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において二次電子の軌道を示す説明図である。It is explanatory drawing which shows the orbit of a secondary electron in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において一次電子ビームの集束条件の変化に伴い二次電子の軌道が変化することを示す説明図である。It is explanatory drawing which shows that the orbit of a secondary electron changes with the change of the focusing conditions of a primary electron beam in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において集束場レンズの水平外周側に磁界型コイルを設けた場合の二次電子の軌道を示す説明図である。It is explanatory drawing which shows the trajectory of a secondary electron at the time of providing the magnetic field type coil in the horizontal outer peripheral side of a focusing field lens in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において試料を傾斜させた場合の二次電子の軌道を示す説明図である。It is explanatory drawing which shows the track | orbit of a secondary electron at the time of inclining a sample in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において偏向電極板を設け、試料を傾斜させた場合の二次電子の軌道を示す説明図である。It is explanatory drawing which shows the orbit of a secondary electron at the time of providing a deflection electrode plate in the structure of the scanning electron microscope of this invention, and inclining a sample. 本発明の走査型電子顕微鏡の構成において偏向電極板等の詳細を示す図である。It is a figure which shows the detail of a deflection electrode plate etc. in the structure of the scanning electron microscope of this invention. 本発明の走査型電子顕微鏡の構成において平板状電子検出器を備えた場合の二次電子の軌道を示す説明図である。It is explanatory drawing which shows the track | orbit of a secondary electron at the time of providing the flat electron detector in the structure of the scanning electron microscope of this invention. 平板状電子検出器を示す説明図である。It is explanatory drawing which shows a flat electron detector.

符号の説明Explanation of symbols

１、１´、１a…一次電子ビーム
２…磁界レンズ
３…試料
４…走査コイル
５…円筒型の加速電極
６…減速電極
７…試料ステージ
８…制御装置
９…走査制御装置
１０…磁界レンズ制御装置
１１、２９…二次電子検出器
１２…表示装置
１３、１４、１５、３３、３４、３５…可変電極
２０…減速場レンズ、加速場レンズ
２１…制限絞り
２２…開き角制御レンズ
２３…基準電圧電極
２４、２４´…収集電極
２５…第１分散電極
２６…第２分散電極
２７…第１加速電極
２８…第２加速電極
３０…分散電極制御装置
３６…加速場レンズ、減速場レンズ
４１Ａ、４１Ｂ、４１Ｃ…歪み矯正用電極板
４３、４４…漏洩電界
４５…平板状電子検出器
１２、１２´、３７、３７´、３７a、３７b、３７a´３７b´、３７a´´３７b´´、３８、４６a、４６b…二次電子 DESCRIPTION OF SYMBOLS 1, 1 ', 1a ... Primary electron beam 2 ... Magnetic lens 3 ... Sample 4 ... Scanning coil 5 ... Cylindrical acceleration electrode 6 ... Deceleration electrode 7 ... Sample stage 8 ... Control device 9 ... Scanning control device 10 ... Magnetic lens control Device 11, 29 ... Secondary electron detector 12 ... Display device 13, 14, 15, 33, 34, 35 ... Variable electrode 20 ... Deceleration field lens, acceleration field lens 21 ... Restriction aperture 22 ... Opening angle control lens 23 ... Reference Voltage electrode 24, 24 '... collection electrode 25 ... first dispersion electrode 26 ... second dispersion electrode 27 ... first acceleration electrode 28 ... second acceleration electrode 30 ... dispersion electrode controller 36 ... acceleration field lens, deceleration field lens 41A, 41B, 41C ... distortion correcting electrode plates 43, 44 ... leakage electric field 45 ... flat electron detectors 12, 12 ', 37, 37', 37a, 37b, 37a'37b ', 37a "37b", 38, 46a, 46b ... secondary electrons

Claims (14)

荷電粒子ビーム源、該荷電粒子ビーム源からの荷電粒子ビームを加速及び集束する加速集束レンズ系、該加速及び集束された荷電粒子ビームを減速して試料上に集束する減速集束レンズ系、該荷電粒子ビームで前記試料上を走査させるための走査レンズ系、前記減速集束レンズ系で加速及び集束され、前記加速集束レンズ系で減速及び集束された二次荷電粒子ビームの進行方向を変える第１方向変更レンズ系、該方向変更レンズ系により入って来る二次荷電粒子ビームをエネルギーに応じて進行方向を変える第２方向変更レンズ系、該第２方向変更レンズ系からの二次荷電粒子ビームを検出する二次荷電粒子ビーム検出器、及び、該検出された二次荷電粒子ビームに基づいて前記試料の二次荷電粒子ビーム像を表示する表示装置を備えた荷電粒子ビーム装置。 A charged particle beam source, an acceleration focusing lens system for accelerating and focusing a charged particle beam from the charged particle beam source, a decelerating focusing lens system for decelerating and focusing the accelerated and focused charged particle beam on a sample, the charging A scanning lens system for scanning the sample with a particle beam, a first direction that changes the traveling direction of the secondary charged particle beam accelerated and focused by the decelerating focusing lens system and decelerated and focused by the accelerating focusing lens system Detecting the secondary charged particle beam from the second direction change lens system, the second direction change lens system that changes the traveling direction of the secondary charged particle beam that is incident by the change lens system, the direction change lens system according to the energy A secondary charged particle beam detector, and a charge provided with a display device for displaying a secondary charged particle beam image of the sample based on the detected secondary charged particle beam Child beam device. 荷電粒子ビーム源、該荷電粒子ビーム源からの荷電粒子ビームを加速及び集束する加速集束レンズ系、該加速及び集束された荷電粒子ビームを減速して試料上に集束する減速集束レンズ系、該荷電粒子ビームで前記試料上を走査させるための走査レンズ系、前記減速集束レンズ系で加速及び集束され、前記加速集束レンズ系で減速及び集束された二次荷電粒子ビームの進行方向を変える第１方向変更レンズ系、該方向変更レンズ系により入って来る二次荷電粒子ビームを前記第１方向変更レンズ系とでエネルギーに応じて進行方向を変える第２方向変更レンズ系、該第２方向変更レンズ系からの二次荷電粒子ビームを検出する二次荷電粒子ビーム検出器、及び、該検出された二次荷電粒子ビームに基づいて前記試料の二次荷電粒子ビーム像を表示する表示装置を備えた荷電粒子ビーム装置。 A charged particle beam source, an acceleration focusing lens system for accelerating and focusing a charged particle beam from the charged particle beam source, a decelerating focusing lens system for decelerating and focusing the accelerated and focused charged particle beam on a sample, the charging A scanning lens system for scanning the sample with a particle beam, a first direction that changes the traveling direction of the secondary charged particle beam accelerated and focused by the decelerating focusing lens system and decelerated and focused by the accelerating focusing lens system Change lens system, second direction change lens system for changing the traveling direction of the secondary charged particle beam coming from the direction change lens system according to energy with the first direction change lens system, and the second direction change lens system A secondary charged particle beam detector for detecting a secondary charged particle beam from the sample, and a secondary charged particle beam image of the sample based on the detected secondary charged particle beam Charged particle beam device with a Shimesuru display device. 前記加速集束レンズ系は、三枚の電極から成り、そのうち前記荷電粒子ビーム源側の電極は集束位置を調整するための電極である請求項１又は２記載の荷電粒子ビーム装置。 The charged particle beam apparatus according to claim 1 or 2, wherein the acceleration focusing lens system includes three electrodes, and the electrode on the charged particle beam source side is an electrode for adjusting a focusing position. 前記減速集束レンズ系は、筒状の加速電極と減速電極から成ることを特徴とする請求項１又は２記載の荷電粒子ビーム装置。 3. The charged particle beam apparatus according to claim 1, wherein the decelerating and focusing lens system includes a cylindrical acceleration electrode and a decelerating electrode. 前記加速集束系レンズを成す三枚の電極のうち、試料側の電極が前記筒状の加速電極に固定されていること特徴とする請求項４記載の荷電粒子ビーム装置。 5. The charged particle beam apparatus according to claim 4, wherein, of the three electrodes constituting the acceleration focusing system lens, an electrode on the sample side is fixed to the cylindrical acceleration electrode. 前記第２の方向変更系レンズは、二枚のドーナツ状の電極が互いに接触しないように対向配置されて成る請求項１記載の荷電粒子ビーム装置。 2. The charged particle beam apparatus according to claim 1, wherein the second direction-changing system lens is disposed to face each other so that two donut-shaped electrodes do not contact each other. 前記第２の方向変更系レンズを成すドーナツ状の電極の一方は、前記試料に対向している面が前記荷電粒子ビーム源側に凹状に湾曲しており、他方は、前記荷電粒子ビーム源に対向している面が前記試料側に凹状に湾曲している請求項６記載の荷電粒子ビーム装置。 One of the donut-shaped electrodes forming the second direction changing system lens has a surface facing the sample that is concavely curved toward the charged particle beam source, and the other is connected to the charged particle beam source. The charged particle beam apparatus according to claim 6, wherein the opposed surfaces are curved concavely toward the sample side. 前記二次荷電粒子ビーム検出器は中央部に荷電粒子ビーム通加孔を有するドーナツ板状の検出器から成り、該孔内に前記第１の方向変更系レンズが配置されている請求項２記載の荷電粒子ビーム装置。 3. The secondary charged particle beam detector comprises a donut plate-shaped detector having a charged particle beam addition hole in the center thereof, and the first direction changing system lens is disposed in the hole. Charged particle beam device. 前記減速電極への印加電圧及び／若しくは前記筒状の加速電極への印加電圧により前記試料から発生する荷電粒子ビームの光軸に対する放射方向をコントロールするように成した請求項４記載の荷電粒子ビーム装置 The charged particle beam according to claim 4, wherein a radiation direction with respect to an optical axis of the charged particle beam generated from the sample is controlled by an applied voltage to the deceleration electrode and / or an applied voltage to the cylindrical acceleration electrode. apparatus 前記加速集束レンズ系による二次荷電粒子ビームの集束点近傍に、二次荷電粒子を集束させる磁場若しくは電場を形成する磁界コイル若しくは静電電極を設けたことを特徴とする請求項１又は２の荷電粒子ビーム装置。 The magnetic field coil or electrostatic electrode for forming a magnetic field or an electric field for focusing the secondary charged particles is provided in the vicinity of a focusing point of the secondary charged particle beam by the accelerating focusing lens system. Charged particle beam device. 前記減速電極に沿って少なくとも三方から該減速電極を取り囲む様に少なくとも三枚の歪み矯正用電極を配置した請求項４記載の荷電粒子ビーム装置。 The charged particle beam apparatus according to claim 4, wherein at least three distortion correcting electrodes are disposed so as to surround the deceleration electrode from at least three sides along the deceleration electrode. 前記各歪み矯正用電極各々に個別に電圧を印加する手段を設けた請求項１１記載の荷電粒子ビーム装置。 The charged particle beam apparatus according to claim 11, further comprising means for individually applying a voltage to each of the distortion correcting electrodes. 前記ドーナツ板状荷電粒子ビーム検出器は、周方向及び放射方向に複数分割され、各分割部からそれぞれ独立して前記試料からの二次荷電粒子ビームが検出される様に成した請求項８記載の荷電粒子ビーム装置。 9. The donut plate-like charged particle beam detector is divided into a plurality of circumferential and radial directions, and a secondary charged particle beam from the sample is detected independently of each divided portion. Charged particle beam device. 前記加速集束レンズ系を成す三枚の電極のうち、中間に配置された電極と荷電粒子ビーム源側の電極とで二次荷電粒子の開き角を調整するように成した請求項３記載の荷電粒子ビーム装置。 The charge according to claim 3, wherein an opening angle of the secondary charged particles is adjusted by an electrode arranged in the middle of the three electrodes constituting the accelerating and focusing lens system and an electrode on the charged particle beam source side. Particle beam device.

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