JP2008269967A - Electron beam spin detector - Google Patents

Electron beam spin detector Download PDF

Info

Publication number
JP2008269967A
JP2008269967A JP2007111695A JP2007111695A JP2008269967A JP 2008269967 A JP2008269967 A JP 2008269967A JP 2007111695 A JP2007111695 A JP 2007111695A JP 2007111695 A JP2007111695 A JP 2007111695A JP 2008269967 A JP2008269967 A JP 2008269967A
Authority
JP
Japan
Prior art keywords
spin
electron beam
detector
secondary electrons
sample
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.)
Pending
Application number
JP2007111695A
Other languages
Japanese (ja)
Inventor
Tadashi Mizoguchi
正 溝口
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
APCO KK
Original Assignee
APCO KK
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by APCO KK filed Critical APCO KK
Priority to JP2007111695A priority Critical patent/JP2008269967A/en
Publication of JP2008269967A publication Critical patent/JP2008269967A/en
Pending legal-status Critical Current

Links

Images

Abstract

<P>PROBLEM TO BE SOLVED: To display a magnetic domain at a high S/N ratio with extremely high resolution by a simple structure and by increasing a prospective angle of a sample with respect to a primary electron beam irradiation position, in relation to an electron beam spin detector detecting a magnetic domain structure of a sample including a magnetic domain irradiated with a primary electron beam narrowed down by an objective lens of a scanning electron microscope. <P>SOLUTION: This electron beam spin detector is provided with: a spin detector arranged between an objective lens of a scanning electron microscope and a sample including a magnetic domain, and composed by arranging a plurality of spin polarization detectors detecting spin polarization of secondary electrons emitted to the circumference around the position of the sample irradiated with a primary electron beam, and each comprising two symmetrical partial detection parts; and a spin direction determination means determining a spin direction at the irradiation position of the primary electron beam of the sample based on the difference among the spin polarizations of the secondary electrons respectively detected by the plurality of spin polarization detectors constituting the spin detector. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、走査型電子顕微鏡などの対物レンズで細く絞った１次電子ビームで照射した磁区を含む試料の磁区構造を検出する電子線スピン検出器に関するものである。   The present invention relates to an electron beam spin detector that detects a magnetic domain structure of a sample including a magnetic domain irradiated with a primary electron beam that is narrowed by an objective lens such as a scanning electron microscope.

従来、磁性体の磁化領域（磁区）を観察するには、光学顕微鏡を用いたピッター法や直線偏向を使ったカー効果を用いた手法がある。これら光学顕微鏡を用いた手法では、磁区の微細構造は当該光学顕微鏡の分解能が限界であった。   Conventionally, in order to observe the magnetization region (magnetic domain) of a magnetic material, there are methods using a Pitter method using an optical microscope and a Kerr effect using linear deflection. In the technique using these optical microscopes, the resolution of the optical microscope is limited to the fine structure of the magnetic domain.

これに比して分解能が２桁程度高い、走査型電子顕微鏡を使って磁性体の磁区の微細構造を観察する手法として、図６に示すＭｏｔｔ型検出器がある。   A Mott type detector shown in FIG. 6 is a technique for observing the fine structure of the magnetic domain of a magnetic material using a scanning electron microscope having a resolution of about two digits higher than this.

図６のＭｏｔｔ型検出器は、１次電子ビームを試料（観察対象の磁性体試料）に照射し、当該試料より放出された２次電子を２５〜２００ＫＶの高電圧で加速し、加速した２次電子を金等のターゲットに垂直に照射し、その散乱電子を当該ターゲットを中心に円周状に配置したチャネルトロン検出器等でそれぞれ検出し、散乱電子の僅かな非対称性をもとに試料（観察対象の磁性体試料）の磁区を画像として表示装置に表示するものである。   The Mott-type detector shown in FIG. 6 irradiates a sample (magnetic sample to be observed) with a primary electron beam, accelerates secondary electrons emitted from the sample at a high voltage of 25 to 200 KV, and accelerates 2 A secondary electron is irradiated perpendicularly to a target such as gold, and the scattered electrons are detected by a channeltron detector or the like arranged circumferentially around the target, and a sample based on a slight asymmetry of the scattered electrons. The magnetic domain of the (magnetic sample to be observed) is displayed on the display device as an image.

従来の上述した前者の光学顕微鏡を使った磁区観察では、分解能が低く微細構造、例えば数十ｎｍの構造を観察することが不可であるという問題があった。   In the conventional magnetic domain observation using the former optical microscope described above, there is a problem that it is impossible to observe a fine structure, for example, a structure of several tens of nm, with low resolution.

従来の上述した後者の図６のＭｏｔｔ型検出器を用いた磁区観察では、試料から放出された２次電子を２５〜２００ＫＶの高電圧で加速し、更に、金のターゲットに垂直に照射し、かつその散乱電子を複数のチャネルトロン検出器等で検出して非対称性をもとに磁区を表示する必要があり、高加速するために装置が大げさになってしまうと共に、試料より相当離れた位置に検出器（チャネルトロン検出器等）を置かざるを得ない構造となり試料に対する見込み角が小さくなって信号量が少なく高Ｓ／Ｎ比を得難いという根本的な欠点が存在するという問題があった。更に、金ターゲットやチャネルトロン検出器やマルチチャネルプレートなどを使うために高真空が更に要求されてしまうという問題もあった。   In the conventional magnetic domain observation using the latter Mott-type detector of FIG. 6 described above, secondary electrons emitted from the sample are accelerated at a high voltage of 25 to 200 KV, and further, a gold target is irradiated vertically. And it is necessary to detect the scattered electrons with multiple channeltron detectors and display the magnetic domain based on the asymmetry, and the device is exaggerated due to high acceleration, and the position is far away from the sample. Detector (channeltron detector, etc.) has to be placed on the surface, and there is a problem that there is a fundamental drawback that the angle of view with respect to the sample becomes small and the signal amount is small and it is difficult to obtain a high S / N ratio. . Furthermore, there is a problem that a high vacuum is further required to use a gold target, a channeltron detector, a multichannel plate, and the like.

また、Ｍｏｔｔ型の欠点を一部解決する手法として、試料より発生した２次電子を当該試料近傍で偏向器で偏向し、途中にレンズを設けて発散を抑えながらＭｏｔｔ検出器に当該２次電子を導入する手法もあるが、いずれにしても、Ｍｏｔｔ型検出器の構造が大型かつ多数のチャネルトロン検出器を用いる必要があり、装置が大げさかつ充分な見込み角を確保して高Ｓ／Ｎ比で試料の磁区のスピン方向を検出して画像（磁区）を表示し得ないという問題があった。   Further, as a technique for partially solving the disadvantages of the Mott type, secondary electrons generated from a sample are deflected by a deflector in the vicinity of the sample, and a lens is provided in the middle to suppress the divergence while the secondary electron is applied to the Mott detector However, in any case, the structure of the Mott detector must be large and a large number of channeltron detectors must be used. There is a problem that the image (magnetic domain) cannot be displayed by detecting the spin direction of the magnetic domain of the sample by the ratio.

本発明は、これらの問題を解決するため、対物レンズで細く絞った１次電子ビームで照射した磁区を含む試料の磁区構造を検出する電子線スピン検出器において、対物レンズと磁区を含む試料との間に設け、１次電子ビームで照射した試料の位置を中心に、周囲に放出された２次電子のスピン偏極を検出する、対称の２つの部分検出部からなるスピン偏極検出器を、複数配置したスピン検出器と、スピン検出器を構成する複数のスピン偏極検出器でそれぞれ検出した２次電子のスピン偏極の違いをもとに試料の１次電子ビームの照射位置のスピン方向を判定するスピン方向判定手段とを備えるようにしている。   In order to solve these problems, the present invention provides an electron beam spin detector for detecting a magnetic domain structure of a sample including a magnetic domain irradiated with a primary electron beam narrowed by an objective lens. A spin polarization detector comprising two symmetric partial detectors for detecting the spin polarization of secondary electrons emitted around the position of the sample irradiated with the primary electron beam. The spin at the irradiation position of the primary electron beam of the sample based on the difference in the spin polarization of the secondary electrons detected by the plurality of arranged spin detectors and the plurality of spin polarization detectors constituting the spin detector. Spin direction determination means for determining the direction is provided.

この際、対称の２つの部分検出部として、直角三角錐あるいは直角三角錐の斜面をもちかつ当該直角三角錐の斜面あるいは当該斜面が対称で相互に電気的に絶縁したそれぞれの当該斜面の部分に２次電子をそれぞれ照射させて吸収させ、当該吸収された２次電子の電流量の差を検出してスピン偏極を検出するようにしている。   At this time, as the two symmetrical partial detectors, the slopes of the right triangle pyramid or the right triangle pyramid and the slopes of the right triangle pyramid or the slopes of the slopes which are symmetrical and electrically insulated from each other are provided. Each of the secondary electrons is irradiated and absorbed, and a difference in current amount of the absorbed secondary electrons is detected to detect spin polarization.

また、直角三角錐あるいは直角三角錐の斜面の代わりに、当該直角三角錐の斜面あるいは当該斜面の部分を凹面形状とするようにしている。   Further, instead of the right triangular pyramid or the inclined surface of the right triangular pyramid, the inclined surface of the right triangular pyramid or the portion of the inclined surface has a concave shape.

また、吸収された２次電子の電流量の差を、当該電流量の和で除算して正規化するようにしている。   Also, the difference in the amount of current of the absorbed secondary electrons is normalized by dividing by the sum of the amount of current.

また、あるスピン偏極検出器と他のスピン偏極検出器との間に、シールド板を配置するようにしている。   In addition, a shield plate is arranged between a certain spin polarization detector and another spin polarization detector.

また、シールド板を２次電子を可及的に吸収かつ反射の少ない材質で形成あるいはコーティング、あるいは表面を凹凸にするようにしている。   In addition, the shield plate is formed or coated with a material that absorbs secondary electrons as much as possible and has little reflection, or the surface is made uneven.

また、シールド板の材質あるいはコーティングする材質をカーボンとするようにしている。   Further, the material of the shield plate or the material to be coated is made of carbon.

本発明は、走査型電子顕微鏡などの対物レンズの下面と試料との間に、当該試料の１次電子ビーム照射位置を中心に、当該位置から周囲に放出された２次電子のスピン偏極の度合いを検出可能な検出器をリング状に複数配置し、当該複数の検出器の各位置におけるスピン偏極の度合いの違いをもとに試料の磁区を表示することにより、簡単な構造、かつ試料の１次電子ビーム照射位置に対する見込み角を大きくして高Ｓ／Ｎ比で磁区を極めて高分解能で表示することが可能となる。   The present invention relates to the spin polarization of secondary electrons emitted from the lower surface of an objective lens such as a scanning electron microscope and the sample around the primary electron beam irradiation position of the sample. By arranging multiple detectors capable of detecting the degree in a ring shape and displaying the magnetic domain of the sample based on the difference in the degree of spin polarization at each position of the multiple detectors, a simple structure and sample It is possible to display the magnetic domain with a very high resolution at a high S / N ratio by increasing the angle of view with respect to the primary electron beam irradiation position.

本発明は、走査型電子顕微鏡などの対物レンズの下面と試料との間に、当該試料の１次電子ビーム照射位置を中心に、当該位置から周囲に放出された２次電子のスピン偏極の度合いを検出可能な検出器をリング状に複数配置し、当該複数の検出器の各位置におけるスピン偏極の度合いの違いをもとに試料の磁区を表示し、簡単な構造、かつ試料の１次電子ビーム照射位置に対する見込み角を大きくして高Ｓ／Ｎ比で磁区を極めて高分解能で表示することを実現した。   The present invention relates to the spin polarization of secondary electrons emitted from the lower surface of an objective lens such as a scanning electron microscope and the sample around the primary electron beam irradiation position of the sample. A plurality of detectors capable of detecting the degree are arranged in a ring shape, and the magnetic domain of the sample is displayed based on the difference in the degree of spin polarization at each position of the plurality of detectors. The prospective angle with respect to the irradiation position of the secondary electron beam was increased, and the magnetic domain was displayed with a very high resolution at a high S / N ratio.

図１は、本発明の１実施例構造図を示す。
図１の（ａ）は要部断面図を示す。 FIG. 1 shows a structural diagram of one embodiment of the present invention.
FIG. 1A shows a cross-sectional view of the main part.

図１の（ａ）において、ＳＥＭ鏡筒部１は、公知の走査型電子顕微鏡を構成する鏡筒部であって、電子線発生源、電子線発生源で発生された１次電子線を集束するコンデンサレンズ、コンデンサレンズで集束された１次電子ビームを磁性試料４上に細く絞る対物レンズ２、および磁性試料４上に細く絞られた１次電子ビームを平面走査する走査系（Ｘ方向およびＹ方向に走査する偏向走査系）などから構成されるものである。ここでは、ＳＥＭ鏡筒１の下部に図示の対物レンズ２を設けたものである。   In FIG. 1A, an SEM barrel 1 is a barrel constituting a known scanning electron microscope, and focuses an electron beam generation source and a primary electron beam generated by the electron beam generation source. A condenser lens, an objective lens 2 for narrowing the primary electron beam focused by the condenser lens onto the magnetic sample 4, and a scanning system for scanning the surface of the primary electron beam thinly focused on the magnetic sample 4 (in the X direction and A deflection scanning system for scanning in the Y direction). Here, the illustrated objective lens 2 is provided in the lower part of the SEM column 1.

対物レンズ２は、１次電子ビームを、磁性試料４の上に細く絞るものである。ここでは、当該対物レンズ２と磁性試料４との間の空間（あるいは距離（ＷＤ））に、本発明に係るスピン検出器１１を図示のように配置する。   The objective lens 2 narrows the primary electron beam onto the magnetic sample 4. Here, the spin detector 11 according to the present invention is arranged in the space (or distance (WD)) between the objective lens 2 and the magnetic sample 4 as shown in the figure.

磁性材料４は、１次電子ビームを対物レンズ２で細く絞って照射しつつ、図示外の偏向系で平面走査し、そのときに放出された２次電子のスピン方向を本発明に係るスピン検出器１１で検出し、当該磁性材料４の磁区を画面上に表示する対象の試料である。   The magnetic material 4 irradiates the primary electron beam by narrowing it with the objective lens 2 and performs plane scanning with a deflection system (not shown), and the spin direction of the secondary electrons emitted at that time is detected by the spin detection according to the present invention. This is a sample to be detected by the vessel 11 and displaying the magnetic domains of the magnetic material 4 on the screen.

試料室５は、磁性材料４およびスピン検出器１１などを真空中に保持する部屋であって、図示外の真空排気系で真空配置される部屋である。   The sample chamber 5 is a chamber that holds the magnetic material 4 and the spin detector 11 in a vacuum, and is a chamber that is vacuum-arranged by a vacuum exhaust system (not shown).

２次電子６は、１次電子を磁性材料４に照射したときに当該１次電子の照射点を中心に周囲に放出される２次電子である。本発明のスピン検出器１１で磁性材料４の磁区のスピン方向を検出するときは通常のＳＥＭのように、これに具備する検出器の集束用の正電圧を印加することなく、ほぼゼロ電位（試料室５の電位）に保持し、２次電子が１次電子の照射点から放出された方向にそのまま走行するようにし、その方向に走行した当該２次電子についてスピン検出器１１で電子のスピンの偏極度合い（非対称性）をそれぞれ検出し、偏極度合い（非対称性）の最大の方向がスピン方向（偏極方向）と判定する（図３を用いて後述する）。   The secondary electrons 6 are secondary electrons emitted around the irradiation point of the primary electrons when the magnetic material 4 is irradiated with the primary electrons. When the spin direction of the magnetic domain 4 of the magnetic material 4 is detected by the spin detector 11 of the present invention, as in the case of an ordinary SEM, a positive voltage for focusing of the detector included in the magnetic material 4 is not applied, and almost zero potential ( The potential of the sample chamber 5), the secondary electrons travel as they are in the direction emitted from the irradiation point of the primary electrons, and the spin detector 11 spins electrons with respect to the secondary electrons traveling in that direction. The degree of polarization (asymmetric) is detected, and the maximum direction of the degree of polarization (asymmetric) is determined as the spin direction (polarization direction) (described later with reference to FIG. 3).

スピン検出器１１は、複数のスピン偏極検出器１２を、１次電子ビームを磁性材料４に照射した位置を中心に、放射状に配置したものであって（図３の（ａ）参照）、１次電子ビームを磁性材料４に照射した場所のスピン方向（磁区のスピン方向）を検出するものである（図１から図５を用いて後述する）。スピン検出器１１は、図示外の機構により、図示の状態に挿入して磁区を表示する構成にしたり、外部に引き出して通常のＳＥＭ（２次電子像、反射電子像を表示するＳＥＭ）として動作させたり、必要に応じて切り替えることが可能となっている。   The spin detector 11 is configured by arranging a plurality of spin polarization detectors 12 radially around a position where the magnetic material 4 is irradiated with the primary electron beam (see FIG. 3A). The spin direction (spin direction of the magnetic domain) where the primary electron beam is applied to the magnetic material 4 is detected (described later with reference to FIGS. 1 to 5). The spin detector 11 is configured to display a magnetic domain by being inserted into the state shown in the figure by a mechanism not shown in the figure, or operated as a normal SEM (SEM that displays a secondary electron image or a reflected electron image) by pulling it out to the outside. Or switch as needed.

図１の（ｂ）は、図１の（ａ）に点線で示す方向に見たときの、スピン検出器１１の模式図を示す。ここでは、図１の（ａ）のスピン検出器１１は、外側から中心方向に眺めると、図１の（ｂ）に示すように、直角三角形を２組対称に配置した構造となり、実際は直角三角錐を２組、対称に電気的に絶縁して配置した構造となる（図２参照）。   FIG. 1B is a schematic diagram of the spin detector 11 when viewed in the direction indicated by the dotted line in FIG. Here, when viewed from the outside toward the center, the spin detector 11 in FIG. 1A has a structure in which two sets of right triangles are arranged symmetrically as shown in FIG. Two cones are arranged symmetrically and electrically insulated (see FIG. 2).

図１の（ｃ）は、図１の（ｂ）のスピン偏極検出器１２を拡大および、磁性試料４から放出された２次電子が照射する方向および当該スピン偏極検出器１２を構成する対称の２つの部分で電流を検出する様子を模式的に示す。図１の（ａ）で１次電子ビームを磁性試料４に照射したときに上斜め方向に放出される２次電子が、図１の（ｃ）の下から上方向に走行する２次電子に相当する。２次電子は、スピン偏極検出器１２を構成する対称の２つの部分（直角三角錐）の斜面にそれぞれ図示のように衝突して吸収される。対称の２つの部分（直角三角錐）の角度はここでは、２５°近辺（１５〜３５°程度）が最大の偏極度（非対称性）を検出する角度である（図１の（ｄ）参照）。２つの直角三角錐の部分に吸収される２次電子の電流をそれぞれＩ右、Ｉ左として測定し、両者の差を両者の和で除算し、偏極度合い（非対称性）を算出する。   FIG. 1C enlarges the spin polarization detector 12 of FIG. 1B, configures the direction of irradiation of secondary electrons emitted from the magnetic sample 4 and the spin polarization detector 12. A state in which current is detected in two symmetrical parts is schematically shown. In FIG. 1A, when the magnetic sample 4 is irradiated with the primary electron beam, the secondary electrons emitted in the diagonally upward direction become secondary electrons that travel upward from the bottom of FIG. Equivalent to. The secondary electrons collide with the inclined surfaces of two symmetrical parts (right triangular pyramids) constituting the spin polarization detector 12 as shown in the figure and are absorbed. Here, the angle between the two symmetrical parts (right triangular pyramid) is an angle at which the maximum degree of polarization (asymmetric) is detected in the vicinity of 25 ° (about 15 to 35 °) (see (d) in FIG. 1). . The secondary electron current absorbed in the two right triangular pyramids is measured as I right and I left, respectively, and the difference between the two is divided by the sum of both to calculate the degree of polarization (asymmetry).

図１の（ｄ）は、図１の（ｃ）のスピン偏極検出器１２の左側、および右側で検出される２次電子の電流の大きさを模式的に説明する図を示す。   FIG. 1D is a diagram schematically illustrating the magnitude of the secondary electron current detected on the left and right sides of the spin polarization detector 12 in FIG.

図１の（ｄ−１）は図１の（ｃ）のスピン偏極検出器１２を構成する左側の直角三角錐で２次電子を検出するときの様子を模式的に示し、図１の（ｄ−２）は図１の（ｃ）のスピン偏極検出器１２を構成する右側の直角三角錐で２次電子を検出するときの様子を模式的に示す。   (D-1) in FIG. 1 schematically shows a state in which secondary electrons are detected by the left right triangular pyramid constituting the spin polarization detector 12 in FIG. 1 (c). d-2) schematically shows a state in which secondary electrons are detected by the right-sided right triangular pyramid constituting the spin polarization detector 12 of FIG.

図１の（ｄ−１）において、図１の（ａ）で１次電子を磁性試料４に照射して放出された２次電子線について、放出されたときに磁性材料４の磁区（スピン）によってここでは、紙面の裏から表側にスピン偏極方向となるように偏極されたとすると、当該２次電子線（スピン偏極方向として紙面の裏から表方向に持つ）が約２５°の直角三角錐の斜面に図示のように入射すると、左方向に反射される割合が減少し（弱くなり）、結果として、吸収される２次電子の電流量Ｉ左が増大した値として検出される。   1 (d-1), the secondary electron beam emitted by irradiating the magnetic sample 4 with the primary electrons in FIG. 1 (a) is magnetic domain (spin) of the magnetic material 4 when emitted. Thus, assuming that the spin polarization direction is polarized from the back side to the front side of the paper surface, the secondary electron beam (having the spin polarization direction from the back side of the paper surface to the front direction) is a right angle of about 25 °. When entering the slope of the triangular pyramid as shown in the figure, the ratio of reflection in the left direction decreases (becomes weak), and as a result, the current amount I left of the absorbed secondary electrons is detected as an increased value.

一方、直角三角錐の斜面の向きが逆の図１の（ｄ−２）の場合には、右方向に２次電子が反射される割合が増大し（強くなり）、結果として、吸収される２次電子の電流量Ｉ右は減少した値として検出される。   On the other hand, in the case of (d-2) in FIG. 1 in which the direction of the slope of the right triangular pyramid is reversed, the ratio of secondary electrons reflected to the right increases (becomes stronger) and is absorbed as a result. The current amount I right of the secondary electrons is detected as a decreased value.

以上のように、図１の（ｄ−１）で測定したＩ左と、図１の（ｄ−２）で測定したＩ右との差を、両者の和で除算した値は、２次電子のスピンの偏極度合い（非対称性）（図１の（ａ）で１次電子ビーム３が磁性試料４に照射して２次電子が放出されたときに、当該２次電子が磁性材料４の磁区から受けたスピン偏極の度合い）について、当該スピン偏極検出器１２の配置した方向における大きさを検出することが可能となる。従って、リング状にスピン偏極検出器１２を複数配置し、各スピン偏極検出器１２で検出したスピンの偏極度合い（非対称性）の最大の当該スピン偏極検出器１２の方向がスピン方向に対応したものとして判定できる（図３の（ｂ）参照）。   As described above, the value obtained by dividing the difference between I left measured in (d-1) of FIG. 1 and I right measured in (d-2) of FIG. The degree of spin polarization (asymmetry) (when secondary electrons are emitted when the magnetic sample 4 is irradiated with the primary electron beam 3 in FIG. As for the degree of spin polarization received from the magnetic domain, it is possible to detect the magnitude in the direction in which the spin polarization detector 12 is arranged. Accordingly, a plurality of spin polarization detectors 12 are arranged in a ring shape, and the direction of the spin polarization detector 12 having the maximum degree of spin polarization (asymmetric property) detected by each spin polarization detector 12 is the spin direction. (See (b) of FIG. 3).

図２は、本発明のスピン偏極検出器例を示す。図示のスピン偏極検出器１２は、図１のスピン検出器１１として、１次電子ビームを磁性材料４に照射した位置を中心にリング状に配置する１つの偏極検出器１２を取り出したものである。ＸとＹとからなる面が図１の（ａ）の磁性材料４の表面に対応する面に対応し、Ｚ方向が図１の（ａ）の磁性試料４から上方向である。図示のスピン偏極検出器１２は、直角三角錐を２つ対称に図示のように配置したものであって、検出面Ａとその反対側の図示外の検出面Ａ’が当該直角三角錐の斜面に対応する部分である。１次電子を磁性試料４に照射して放出された２次電子は、図示の検出面Ａと図示外の反対側の検出面Ａ’に下方向から上方向に照射され、既述した図１の（ｄ）で説明したようにスピン偏極方向に応じた電流差（Ｉ左−Ｉ右）を電流和（Ｉ左＋Ｉ右）で除算し、スピン偏極度合い（非対称性）を検出することが可能となる。   FIG. 2 shows an example of a spin polarization detector of the present invention. The illustrated spin polarization detector 12 is obtained by taking out one polarization detector 12 arranged in a ring shape around the position where the magnetic material 4 is irradiated with the primary electron beam as the spin detector 11 of FIG. It is. The surface composed of X and Y corresponds to the surface corresponding to the surface of the magnetic material 4 in FIG. 1A, and the Z direction is upward from the magnetic sample 4 in FIG. The illustrated spin polarization detector 12 has two right-angled triangular pyramids arranged symmetrically as shown in the figure, and the detection surface A and the detection surface A ′ (not shown) on the opposite side of the right-angled triangular pyramid are It corresponds to the slope. The secondary electrons emitted by irradiating the magnetic sample 4 with the primary electrons are irradiated from the lower side to the upper side on the detection surface A ′ on the opposite side to the detection surface A (not shown), and the above-described FIG. As described in (d), the current difference (I left-I right) corresponding to the spin polarization direction is divided by the current sum (I left + I right) to detect the degree of spin polarization (asymmetry). Is possible.

図２の（ｂ）は、図２の（ａ）の直角三角錐のＸ方向から見た様子を模式的に示す。ここでは、直角三角錐の斜面を検出面Ａ（図２の（ａ）の検出面Ａ）と、対応する反対側の検出面Ａ’とを有するものである。試料（図１の（ａ）の磁性試料）は、下方向に位置する。従って、試料（磁性材料４）に上から下方向に１次電子ビームを照射し、上方向（正確には上斜め方向）に放出された２次電子が、図示の検出面Ａ，Ａ’にそれぞれ照射し、既述した図１の（ｄ）で説明したように、当該２次電子が磁性試料４から受けたスピン偏極に応じた偏極度合い（非対称性）（Ｉ左−Ｉ右）／（Ｉ左＋Ｉ右）を検出することが可能となる。   FIG. 2B schematically shows the right triangular pyramid of FIG. 2A viewed from the X direction. Here, a slope of a right triangular pyramid has a detection surface A (detection surface A in FIG. 2A) and a corresponding opposite detection surface A '. The sample (the magnetic sample in FIG. 1A) is located in the downward direction. Accordingly, the sample (magnetic material 4) is irradiated with the primary electron beam from the top to the bottom, and the secondary electrons emitted upward (to be precise, diagonally upward) are incident on the detection surfaces A and A ′ shown in the figure. As described above with reference to FIG. 1D, the degree of polarization (asymmetry) corresponding to the spin polarization received by the secondary electron from the magnetic sample 4 (I left-I right). / (I left + I right) can be detected.

図２の（ｃ）は、検出面Ａ，Ａ’（直角三角形の斜面）を曲面（凹面）にした例を示す。曲面は、２次電子の検出面Ａ，Ａ’への入射角度を２５°近辺になるようにした検出面である。検出面をＹ−Ｚから見ると、その曲線ｚ＝ｆ（ｙ）は、ｚのｙ微分をｆ’（ｙ）として、
ｔａｎ−１（ｆ（ｙ）／ｙ）−ｔａｎ−１（ｆ’（ｙ））＝α
α＝約２５・π／１８０
を満足ｆ（ｙ）は唯一存在し、これを検出面Ａ，Ａ’として用いる。 FIG. 2C shows an example in which the detection surfaces A and A ′ (right-sided triangular slopes) are curved surfaces (concave surfaces). The curved surface is a detection surface in which the incident angle of the secondary electrons to the detection surfaces A and A ′ is around 25 °. When the detection surface is viewed from YZ, the curve z = f (y) is expressed as follows:
tan −1 (f (y) / y) −tan −1 (f ′ (y)) = α
α = about 25 · π / 180
F (y) exists only as a detection surface A and A ′.

尚、検出面Ａ，Ａ’は、通常は金あるいは金スパッタ、金蒸着、金メッキした面である。金の他にトリウムなどの真空中で綺麗に面が保持され、かつ２次電子の偏極を検出しうる金属であればいずれの金属でもよい。   The detection surfaces A and A 'are usually gold or gold sputter, gold vapor deposition, and gold plated surfaces. In addition to gold, any metal may be used as long as the surface is kept clean in a vacuum such as thorium and the polarization of secondary electrons can be detected.

図３は、本発明の実験例を示す。
図３の（ａ）は、スピン偏極検出器１２の５組をθ＝０°、６７．５°、１１２．５°、１８０°、２２５°として配置した例を示す。 FIG. 3 shows an experimental example of the present invention.
FIG. 3A shows an example in which five sets of spin polarization detectors 12 are arranged at θ = 0 °, 67.5 °, 112.5 °, 180 °, and 225 °.

図３の（ｂ）は、図３の（ａ）の構造で、磁性材料４の磁区について測定した非対称性をプロットした曲線を示す。ここで、横軸は図３の（ａ）のスピン偏極検出器１２を配置した角度を表し、縦軸は各スピン偏極検出器１２で既述した図１の（ｄ）で測定した非対称性（偏極度合い）（Ｉ左ーＩ右）／（Ｉ左＋Ｉ右）を表す。また、
○は２０ＫＶ
●は２８ＫＶ
×は３０ＫＶ
は、１次電子の加速電圧を表す。 FIG. 3B shows a curve plotting the asymmetry measured for the magnetic domain of the magnetic material 4 in the structure of FIG. Here, the horizontal axis represents the angle at which the spin polarization detector 12 in FIG. 3A is arranged, and the vertical axis represents the asymmetry measured in each spin polarization detector 12 in FIG. Property (degree of polarization) (I left-I right) / (I left + I right). Also,
○ is 20KV
● is 28KV
× is 30KV
Represents the acceleration voltage of primary electrons.

ここで、図３の（ｂ）の曲線を見ると、ＳＩＮ波となり、その頂点（最大）の角度は、約１３０度で、これがスピンの方向を表すとして判定できる。   Here, looking at the curve of FIG. 3B, it becomes a SIN wave, and the angle of the apex (maximum) is about 130 degrees, which can be determined as representing the spin direction.

従って、１次電子ビーム３を磁性試料４に照射しつつ走査した各位置における、２次電子６のスピンの方向をそれぞれ判定し、磁区画像（特にスピンが反転する場所を明確に表示した磁区画像）として表示することが可能となる。   Accordingly, the direction of the spin of the secondary electrons 6 at each position scanned while irradiating the magnetic sample 4 with the primary electron beam 3 is determined, and a magnetic domain image (particularly, a magnetic domain image clearly displaying the place where the spin is reversed). ) Can be displayed.

図４は、本発明のシールド板例を示す。スピン偏極検出器１２は、例えば図３の（ａ）では５組、１次電子ビーム３を磁性試料４に照射した位置を中心に、リング状に所定角度に配置する。このため、各スピン偏極検出器１２が隣接するスピン偏極検出器１２との間に検出器間シールド２１を設け、２次電子があるスピン偏極検出器１２で吸収されずに反射されて他のスピン偏極検出器１２に入射し、ノイズとなってしまう事態を防止するようにする。この際、検出器間シールド２１は、可及的に２次電子が入射したときに吸収され、反射され難い材質（例えばカーボンで作成、カーボンでコーティング）あるいは構造（表面を微細な凹凸かつカーボンあるいはカーボンコーティングする構造）とする。   FIG. 4 shows an example of the shield plate of the present invention. For example, in FIG. 3A, five sets of the spin polarization detectors 12 are arranged at a predetermined angle in a ring shape with the position where the primary electron beam 3 is irradiated on the magnetic sample 4 as a center. For this reason, an inter-detector shield 21 is provided between each spin polarization detector 12 and the adjacent spin polarization detector 12, and secondary electrons are reflected without being absorbed by the spin polarization detector 12. The incident to other spin polarization detectors 12 to prevent noise is prevented. At this time, the inter-detector shield 21 is absorbed when secondary electrons enter as much as possible, and is not easily reflected (for example, made of carbon, coated with carbon) or structure (the surface has fine unevenness and carbon or Carbon coating structure).

図５は、本発明の検出器ホルダ例を示す。これは、既述したスピン偏極検出器１２を所定角度で複数、リング状に配置して固定する検出器ホルダ３１の例を示す。   FIG. 5 shows an example of a detector holder of the present invention. This shows an example of the detector holder 31 in which a plurality of the above-described spin polarization detectors 12 are arranged and fixed in a ring shape at a predetermined angle.

図５の（ａ）は、検出器ホルダ３１をカーボン製あるいはカーボンを被覆し、不要２次電子の反射を防止する例を示す。   FIG. 5A shows an example in which the detector holder 31 is made of carbon or covered with carbon to prevent reflection of unnecessary secondary electrons.

図５の（ｂ）は、検出器ホルダ３１のスピン偏極検出器１２を固定する側の部分の表面に凹凸を設け、不要２次電子の反射を防止する例を示す。表面の凹凸として、例えば約６０°以上の微細な切り込みを入れ、２次電子の反射を可及的に防止し、高Ｓ／Ｎ比で、既述した非対称性を検出できるようにする。   FIG. 5B shows an example in which unevenness is provided on the surface of the portion of the detector holder 31 on the side where the spin polarization detector 12 is fixed to prevent reflection of unnecessary secondary electrons. As the unevenness of the surface, for example, a fine cut of about 60 ° or more is provided to prevent reflection of secondary electrons as much as possible, and the above-described asymmetry can be detected with a high S / N ratio.

本発明は、簡単な構造、かつ試料の１次電子ビーム照射位置に対する見込み角を大きくして高Ｓ／Ｎ比で磁区を極めて高分解能で表示する電子線スピン検出器に関するものである。   The present invention relates to an electron beam spin detector that displays a magnetic domain with a high S / N ratio and an extremely high resolution by increasing a prospective angle with respect to a primary electron beam irradiation position of a sample with a simple structure.

本発明の１実施例構造図である。1 is a structural diagram of an embodiment of the present invention. 本発明のスピン偏極検出器例である。It is an example of a spin polarization detector of the present invention. 本発明の実験例である。It is an example of an experiment of the present invention. 本発明のシールド板例である。It is an example of the shield board of this invention. 本発明の検出器ホルダ例である。It is an example of the detector holder of this invention. 従来技術の説明図である。It is explanatory drawing of a prior art.

符号の説明Explanation of symbols

１：ＳＥＭ鏡筒部
２：対物レンズ
３：１次電子ビーム
４：磁性材料
５：試料室
６：２次電子
１１：スピン検出器
１２：スピン偏極検出器
２１：検出器間シールド
３１：検出器ホルダ 1: SEM column part 2: Objective lens 3: Primary electron beam 4: Magnetic material 5: Sample chamber 6: Secondary electron 11: Spin detector 12: Spin polarization detector 21: Inter-detector shield 31: Detection Holder

Claims (7)

対物レンズで細く絞った１次電子ビームで照射した磁区を含む試料の磁区構造を検出する電子線スピン検出器において、
前記対物レンズと磁区を含む試料との間に設け、前記１次電子ビームで照射した試料の位置を中心に、周囲に放出された２次電子のスピン偏極を検出する、対称の２つの部分検出部からなるスピン偏極検出器を、複数配置したスピン検出器と、
前記スピン検出器を構成する前記複数のスピン偏極検出器でそれぞれ検出した２次電子のスピン偏極の違いをもとに前記試料の１次電子ビームの照射位置のスピン方向を判定するスピン方向判定手段と、
を備えたことを特徴とする電子線スピン検出器。 In an electron beam spin detector for detecting a magnetic domain structure of a sample including a magnetic domain irradiated with a primary electron beam narrowed down by an objective lens,
Two symmetrical parts that are provided between the objective lens and a sample including a magnetic domain and detect spin polarization of secondary electrons emitted around the position of the sample irradiated with the primary electron beam. A spin detector in which a plurality of spin polarization detectors composed of detectors are arranged;
Spin direction for determining the spin direction of the irradiation position of the primary electron beam of the sample based on the difference in spin polarization of secondary electrons detected by the plurality of spin polarization detectors constituting the spin detector A determination means;
An electron beam spin detector comprising: 前記対称の２つの部分検出部として、直角三角錐あるいは直角三角錐の斜面をもちかつ当該直角三角錐の斜面あるいは当該斜面が対称で相互に電気的に絶縁したそれぞれの当該斜面の部分に前記２次電子をそれぞれ照射させて吸収させ、当該吸収された２次電子の電流量の差を検出してスピン偏極を検出することを特徴とする請求項１記載の電子線スピン検出器。   As the two symmetrical partial detectors, the slope of the right triangular pyramid or the right triangular pyramid and the slope of the right triangular pyramid or the slopes of the slope are symmetrical and electrically insulated from each other, the 2 The electron beam spin detector according to claim 1, wherein secondary electrons are irradiated and absorbed, and a spin polarization is detected by detecting a difference in current amount of the absorbed secondary electrons. 前記直角三角錐あるいは前記直角三角錐の斜面の代わりに、当該直角三角錐の斜面あるいは当該斜面の部分を凹面形状としたことを特徴とする請求項２記載の電子線スピン検出器。   3. The electron beam spin detector according to claim 2, wherein, instead of the right triangular pyramid or the inclined surface of the right triangular pyramid, the inclined surface of the right triangular pyramid or a portion of the inclined surface has a concave shape. 前記吸収された２次電子の電流量の差を、当該電流量の和で除算して正規化したことを特徴とする請求項２あるいは請求項３記載の電子線スピン検出器。   4. The electron beam spin detector according to claim 2, wherein the difference in the amount of current of the absorbed secondary electrons is normalized by dividing by the sum of the amount of current. 前記あるスピン偏極検出器と他のスピン偏極検出器との間に、シールド板を配置したことを特徴とする請求項１から請求項４のいずれかに記載の電子線スピン検出器。   The electron beam spin detector according to any one of claims 1 to 4, wherein a shield plate is disposed between the certain spin polarization detector and another spin polarization detector. 前記シールド板を２次電子を可及的に吸収かつ反射の少ない材質で形成あるいはコーティング、あるいは表面を凹凸にしたことを特徴とする請求項５記載の電子線スピン検出器。   6. The electron beam spin detector according to claim 5, wherein the shield plate is formed or coated with a material that absorbs secondary electrons as much as possible and has little reflection, or the surface is made uneven. 前記材質をカーボンとしたことを特徴とする請求項６記載の電子線スピン検出器。   The electron beam spin detector according to claim 6, wherein the material is carbon.
JP2007111695A 2007-04-20 2007-04-20 Electron beam spin detector Pending JP2008269967A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007111695A JP2008269967A (en) 2007-04-20 2007-04-20 Electron beam spin detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2007111695A JP2008269967A (en) 2007-04-20 2007-04-20 Electron beam spin detector

Publications (1)

Publication Number Publication Date
JP2008269967A true JP2008269967A (en) 2008-11-06

Family

ID=40049211

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2007111695A Pending JP2008269967A (en) 2007-04-20 2007-04-20 Electron beam spin detector

Country Status (1)

Country Link
JP (1) JP2008269967A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011095150A (en) * 2009-10-30 2011-05-12 Fujitsu Ltd Spin detector, surface analyzer, and target
JPWO2020245962A1 (en) * 2019-06-06 2020-12-10

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58218737A (en) * 1982-06-11 1983-12-20 Hitachi Ltd Electron microscope
JPS647461A (en) * 1987-06-29 1989-01-11 Yoshimasa Nihei Device for measuring energy and angle simultaneously
JPH025347A (en) * 1988-06-15 1990-01-10 Teru Barian Kk Ion implantation
JPH04206427A (en) * 1990-11-30 1992-07-28 Hitachi Ltd Spin detector
JPH08220243A (en) * 1995-02-17 1996-08-30 Hitachi Ltd Spin detector
JPH08241690A (en) * 1995-03-06 1996-09-17 Hitachi Ltd Spin polarized scanning electron microscope
JP2002169270A (en) * 2000-12-04 2002-06-14 Nikon Corp Mask inspection apparatus and method of manufacturing semiconductor device

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58218737A (en) * 1982-06-11 1983-12-20 Hitachi Ltd Electron microscope
JPS647461A (en) * 1987-06-29 1989-01-11 Yoshimasa Nihei Device for measuring energy and angle simultaneously
JPH025347A (en) * 1988-06-15 1990-01-10 Teru Barian Kk Ion implantation
JPH04206427A (en) * 1990-11-30 1992-07-28 Hitachi Ltd Spin detector
JPH08220243A (en) * 1995-02-17 1996-08-30 Hitachi Ltd Spin detector
JPH08241690A (en) * 1995-03-06 1996-09-17 Hitachi Ltd Spin polarized scanning electron microscope
JP2002169270A (en) * 2000-12-04 2002-06-14 Nikon Corp Mask inspection apparatus and method of manufacturing semiconductor device

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011095150A (en) * 2009-10-30 2011-05-12 Fujitsu Ltd Spin detector, surface analyzer, and target
JPWO2020245962A1 (en) * 2019-06-06 2020-12-10
WO2020245962A1 (en) * 2019-06-06 2020-12-10 株式会社日立ハイテク Scanning electron microscope
JP7155425B2 (en) 2019-06-06 2022-10-18 株式会社日立ハイテク scanning electron microscope
US11756763B2 (en) 2019-06-06 2023-09-12 Hitachi High-Tech Corporation Scanning electron microscope

Similar Documents

Publication Publication Date Title
JP3786875B2 (en) Objective lens for charged particle beam devices
KR100382026B1 (en) Scanning Electron Microscope
TWI517198B (en) Charged particle detection system and multi-beamlet inspection system
JP5227643B2 (en) An electron beam application device that enables observation with high resolution and high contrast
JP4920385B2 (en) Charged particle beam apparatus, scanning electron microscope, and sample observation method
EP1238405B1 (en) Method and system for the examination of specimen using a charged particle beam
US8969801B2 (en) Scanning electron microscope
JP2004221089A (en) Electron beam device and detection device
US9613779B2 (en) Scanning transmission electron microscope with variable axis objective lens and detective system
JP4200104B2 (en) Charged particle beam equipment
JP2001110351A5 (en)
JP2001110351A (en) Scanning electron microscope
JP5358296B2 (en) Charged particle beam equipment
JP2004513477A (en) SEM with adjustable final electrode for electrostatic objective
JP2003068241A (en) Scanning electron beam device
US7800062B2 (en) Method and system for the examination of specimen
JP4662053B2 (en) Scanning electron microscope with multiple detectors and multiple detector-based imaging method
JP2008269967A (en) Electron beam spin detector
US7767962B2 (en) Method for SEM measurement of features using magnetically filtered low loss electron microscopy
US6670612B1 (en) Undercut measurement using SEM
JP2011222426A (en) Composite charged particle beam device
JP4590590B2 (en) SEM for transmission operation with position sensitive detector
JP2006156134A (en) Reflection imaging electron microscope
JP2023503486A (en) Particle beam system with multi-beam polarizer and beam stop, method of operating particle beam system, and related computer program product
JP5544439B2 (en) Charged particle beam equipment

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20100414

A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20120316

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20120417

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20120821