JP4130798B2

JP4130798B2 - Compound microscope with probe and probe driving method

Info

Publication number: JP4130798B2
Application number: JP2003407615A
Authority: JP
Inventors: 祐介大南; 則幸兼岡
Original assignee: Hitachi High Technologies Corp
Current assignee: Hitachi High Tech Corp
Priority date: 2003-12-05
Filing date: 2003-12-05
Publication date: 2008-08-06
Anticipated expiration: 2023-12-05
Also published as: JP2005167146A

Description

本発明は、プローブ付き顕微鏡に関し、特に、複数の顕微鏡を用いて試料から機械的プローブまでの実際の距離を正確に取得することで、効率良い速度で試料表面にプローブを接触させることができるプローブ付き複合顕微鏡装置、並びにプローブの高さ算出方法及びプローブ駆動方法に関する。 The present invention relates to a microscope with a probe, and in particular, a probe capable of bringing a probe into contact with a sample surface at an efficient speed by accurately acquiring an actual distance from a sample to a mechanical probe using a plurality of microscopes. The present invention relates to a combined microscope apparatus, a probe height calculation method, and a probe driving method.

マイクロプロセッサや半導体メモリなどの半導体集積回路の製造過程において、製品特性の検査のために、電子顕微鏡による配線寸法の計測や、配線パターン上の異物・欠陥検出などが行われている。試料内部にある異常個所の検査には、集束イオンビーム装置（Focused Ion Beam : FIB）と走査型電子顕微鏡（Scanning Electron Microscopy : SEM）が組み合わされたＦＩＢ−ＳＥＭ装置を用いることがある。ＦＩＢ−ＳＥＭ装置では、ＦＩＢを照射した際のスパッタ現象を用いて微細加工を行い、試料内部に存在する欠陥箇所を露出させた後で、ＳＥＭを用いて欠陥箇所を観察することができる。また、このＦＩＢ−ＳＥＭ装置に機械的プローブを備えた装置では、試料からＦＩＢで切り出した微小試料片を機械的プローブで摘出し、高分解能なＳＥＭやＴＥＭで観察することが可能である。機械的プローブ付きＦＩＢ−ＳＥＭ装置に関しては特開２００２−１５０９９０号公報に、微小試料片を摘出するプロセスは特開２００１−２１４６７号公報に詳細に示されている。 In the manufacturing process of a semiconductor integrated circuit such as a microprocessor or a semiconductor memory, measurement of wiring dimensions by an electron microscope, detection of foreign matter / defects on a wiring pattern, and the like are performed for inspection of product characteristics. An FIB-SEM device in which a focused ion beam device (FIB) and a scanning electron microscope (SEM) are combined may be used for inspecting an abnormal part inside a sample. In the FIB-SEM apparatus, microfabrication is performed using a sputtering phenomenon at the time of FIB irradiation to expose a defective portion existing inside the sample, and then the defective portion can be observed using the SEM. In addition, in an apparatus provided with a mechanical probe in this FIB-SEM apparatus, it is possible to extract a micro sample piece cut out from a sample with an FIB and observe it with a high-resolution SEM or TEM. Regarding the FIB-SEM apparatus with a mechanical probe, Japanese Patent Application Laid-Open No. 2002-150990 discloses a detailed process of extracting a micro sample piece.

機械的プローブを用いて試料を摘出するプロセスには、(1) プローブ先端と、プローブ先端を接触させたい試料部位との位置関係を、顕微鏡像から把握し、プローブが試料に接触するまでプローブを駆動するステップと、(2) 微小試料片をプローブ先端に接着して、試料から試料片を摘出した後に、試料片を試料固定台に固定するために、試料片と共にプローブを試料固定台に接近させるステップとがある。この２つのステップにおける共通の作業として、プローブを試料や試料固定台に接近させる動作と、プローブが試料や試料固定台に接触したのを検知した後すぐに、プローブの駆動を停止させる動作がある。 In the process of extracting a sample using a mechanical probe, (1) The positional relationship between the probe tip and the sample site where the probe tip is to be contacted is grasped from the microscopic image, and the probe is moved until the probe contacts the sample. (2) After attaching the small sample piece to the tip of the probe and extracting the sample piece from the sample, the probe is brought close to the sample fixing stand together with the sample piece to fix the sample piece to the sample fixing stand. There are steps to make. Common operations in these two steps include an operation of bringing the probe close to the sample and the sample fixing base and an operation of stopping the driving of the probe immediately after detecting that the probe has contacted the sample and the sample fixing base. .

上記動作に関して、プローブを試料や試料固定台に接近又は接触させる際に注意すべきことは、プローブ速度の設定と接触の検知である。従来は、プローブ速度の設定は作業者が顕微鏡像を目視して行っている。接触の検知方法としては、接触抵抗の変化やプローブに流す電流変化などの電気信号から接触を検知する方法や、顕微鏡像のコントラスト変化を捉えて接触を検知する方法がある。 Regarding the above operation, what is to be noted when the probe is brought close to or in contact with the sample or the sample fixing base is the setting of the probe speed and the detection of the contact. Conventionally, the operator sets the probe speed by visually observing a microscope image. As a contact detection method, there are a method for detecting contact from an electrical signal such as a change in contact resistance or a current change flowing through the probe, and a method for detecting contact by detecting a contrast change in a microscope image.

特開２００２−１５０９９０号公報JP 2002-150990 A 特開２００１−２１４６７号公報JP 2001-21467 A

従来の技術には以下のような問題点がある。
(1) プローブと試料との距離が既知ではない。距離が既知でなければ、プローブ駆動速度の決定が難しい。つまり、もしプローブと試料との距離が近いにも関わらずプローブ速度を速く設定した場合、プローブや試料片が試料や試料固定台に急速に接触し、プローブや試料片が破損してしまう恐れがある。また、もしプローブと試料との距離が遠いにも関わらず、プローブ速度を遅く設定した場合、接近にかかる時間が長くなりすぎる。このために、プローブと試料との距離に応じて、プローブを望ましい速度で駆動する必要がある。
(2) 接触抵抗の変化や電流変化を用いる接触検知は、試料や試料片が絶縁体の場合には非常に難しくなる。また、顕微鏡像からのコントラスト変化による接触検知は、作業者が顕微鏡像を目視して接触の判断を行うために、接触瞬間の検出が曖昧である。もし接触したことに気づかずにプローブ駆動を続ければ、プローブや試料片が破損する恐れがある。 The conventional techniques have the following problems.
(1) The distance between the probe and the sample is not known. If the distance is not known, it is difficult to determine the probe driving speed. In other words, if the probe speed is set high even though the distance between the probe and the sample is short, the probe or sample piece may rapidly come into contact with the sample or sample fixing table, and the probe or sample piece may be damaged. is there. In addition, if the probe speed is set to be slow although the distance between the probe and the sample is long, the time required for the approach becomes too long. For this reason, it is necessary to drive the probe at a desired speed according to the distance between the probe and the sample.
(2) Contact detection using contact resistance change or current change becomes very difficult when the sample or sample piece is an insulator. In addition, the contact detection based on the contrast change from the microscopic image is ambiguous because the operator visually determines the contact by visually observing the microscopic image. If the probe is continuously driven without noticing contact, the probe and the sample piece may be damaged.

上記２つの問題を解決するためには、プローブから試料までの距離を取得し、その距離に応じた最適なプローブ速度でプローブ駆動し、プローブから試料までの距離がゼロになった時にプローブ駆動を停止させることが重要となる。本発明は、このような要請に応えることのできる装置及び方法を提供することを目的とする。 In order to solve the above two problems, the distance from the probe to the sample is acquired, and the probe is driven at an optimum probe speed corresponding to the distance, and the probe is driven when the distance from the probe to the sample becomes zero. It is important to stop. An object of the present invention is to provide an apparatus and a method that can meet such a demand.

上記目的を達成するため、本発明によるプローブ付き複合顕微鏡は、試料のほぼ同一点を観察できる２台以上の顕微鏡と、試料を載置する試料台と、試料に接近又は接触させることを目的とした機械的プローブと、機械的プローブを駆動する駆動機構と、２台以上の顕微鏡から得られる画像から試料とプローブとの見かけの距離の測長を行う測長処理部と、その２つ以上の測長値と顕微鏡の姿勢情報を元に、試料とプローブとの実際の距離を計算する測長データ処理部を備え、試料とプローブとの距離を正確に把握する。顕微鏡の姿勢情報とは、例えば、試料面と顕微鏡光軸のなす角度θ，ω（図１、図１０参照）である。 In order to achieve the above-mentioned object, the composite microscope with a probe according to the present invention aims to bring two or more microscopes capable of observing substantially the same point of a sample, a sample table on which the sample is placed, and a sample to approach or contact the sample. A mechanical probe, a drive mechanism for driving the mechanical probe, a length measurement processing unit for measuring the apparent distance between the sample and the probe from images obtained from two or more microscopes, and two or more of them A length measurement data processing unit that calculates the actual distance between the sample and the probe based on the length measurement value and the attitude information of the microscope is provided to accurately grasp the distance between the sample and the probe. The posture information of the microscope is, for example, angles θ and ω (see FIGS. 1 and 10) formed by the sample surface and the microscope optical axis.

プローブと試料との実際の距離に応じて、プローブを試料に接近させる際のプローブ駆動速度の決定を行うプローブ駆動コントローラを備え、プローブが試料方向に接近している最中に、プローブから試料までの距離を測定し、その距離に応じて、プローブ駆動速度を変更するのが好ましい。そして、プローブが試料方向に接近している最中に、プローブから試料までの距離を測定し、その距離が変化しなくなった時、又はその距離が予想された距離と比べて大きく異なった時をプローブが試料に接触したとして、プローブ駆動を停止させるのが好ましい。 A probe drive controller that determines the probe drive speed when the probe is brought close to the sample according to the actual distance between the probe and the sample, and from the probe to the sample while the probe is approaching the sample direction. It is preferable to measure the distance and change the probe driving speed in accordance with the distance. Then, measure the distance from the probe to the sample while the probe is approaching the sample direction, and when the distance no longer changes, or when the distance is significantly different from the expected distance. It is preferable to stop driving the probe when the probe contacts the sample.

試料表面上の基準点に対する機械的プローブの高さ方向距離を求める本発明の方法は、第１及び第２の顕微鏡を用い、前記基準点が、第１及び第２の顕微鏡による観察画像の中心に来るように調整する第１ステップと、プローブの先端を基準点の直上に位置付ける第２ステップと、第１の顕微鏡による観察画像及び／又は第２の顕微鏡による観察画像上で、基準点とプローブの先端との間の見かけの距離を測長する第３ステップと、見かけの距離と、第１の顕微鏡及び／又は第２の顕微鏡の姿勢情報とを用いてプローブの基準点に対する高さ方向距離を算出する第４ステップとを含む。 The method of the present invention for determining the height direction distance of the mechanical probe with respect to the reference point on the sample surface uses the first and second microscopes, and the reference point is the center of the observation image by the first and second microscopes. A reference point and a probe on the first image and / or the observation image obtained by the second microscope. The height direction distance with respect to the reference point of the probe using the third step of measuring the apparent distance between the tip of the probe, the apparent distance, and the posture information of the first microscope and / or the second microscope And a fourth step of calculating.

この方法の一態様としては、第１の顕微鏡と第２の顕微鏡は、第１の顕微鏡の光軸がプローブを試料方向への駆動する時の駆動方向と一致し、第２の顕微鏡の光軸は前記駆動方向と一致しない位置関係にあり、前記第２ステップは、第１の顕微鏡による観察画像の中心にプローブの先端を位置付けるステップからなり、前記第３のステップは、第２の顕微鏡による観察画像から基準点とプローブの先端との間の見かけの距離を測長するステップからなり、前記第４ステップは、前記見かけの距離と第２の顕微鏡の姿勢情報とを用いて高さ方向の距離を算出する。 As an aspect of this method, the first microscope and the second microscope are configured such that the optical axis of the first microscope coincides with the driving direction when the probe is driven in the sample direction, and the optical axis of the second microscope is Are in a positional relationship that does not coincide with the driving direction, and the second step includes a step of positioning the tip of the probe at the center of the observation image by the first microscope, and the third step is an observation by the second microscope. The method includes a step of measuring an apparent distance between the reference point and the tip of the probe from the image, and the fourth step uses a distance in the height direction using the apparent distance and posture information of the second microscope. Is calculated.

他の態様によると、第１の顕微鏡と第２の顕微鏡は、共に光軸がプローブを試料方向へ駆動する時の駆動方向と一致せず、かつ、第１の顕微鏡の光軸を含み試料面に垂直な第１の平面と第２の顕微鏡の光軸を含み試料面に垂直な第２の平面とが一致しない位置関係にあり、前記第２ステップは、第１の顕微鏡による観察画像上で、プローブの先端を第１の平面に接触させるステップと、第２の顕微鏡による観察画像上で、プローブの先端を第１の平面内で移動して第２の平面に接触させるステップとからなり、前記第３のステップは、第１の顕微鏡による観察画像又は第２の顕微鏡による観察画像上で、基準点とプローブの先端との間の見かけの距離を測長するステップからなり、前記第４のステップは、第１の顕微鏡による観察画像上で測長した見かけの距離と第１の顕微鏡の姿勢情報を用いて、又は第２の顕微鏡による観察画像上で測長した見かけの距離と第２の顕微鏡の姿勢情報とを用いて高さ方向の距離を算出するステップからなる。 According to another aspect, the first microscope and the second microscope both have an optical axis that does not coincide with a driving direction when driving the probe toward the sample, and includes the optical axis of the first microscope. The first plane perpendicular to the second plane and the second plane perpendicular to the sample surface including the optical axis of the second microscope do not coincide with each other, and the second step is performed on the observation image by the first microscope. A step of bringing the tip of the probe into contact with the first plane, and a step of moving the tip of the probe within the first plane on the observation image by the second microscope to make contact with the second plane, The third step includes a step of measuring an apparent distance between the reference point and the tip of the probe on the observation image by the first microscope or the observation image by the second microscope. The steps are measured on the image observed by the first microscope. Using the apparent distance and the posture information of the first microscope, or using the apparent distance measured on the observation image by the second microscope and the posture information of the second microscope, the distance in the height direction is determined. It consists of steps to calculate.

更に他の態様によると、第１の顕微鏡と第２の顕微鏡は、共に光軸が前記プローブを試料方向へ駆動する時の駆動方向と一致せず、かつ、第１の顕微鏡の光軸を含み試料面に垂直な平面と第２の顕微鏡の光軸を含み試料面に垂直な平面が互いに一致する位置関係にあり、前記第２ステップは、第１又は第２の顕微鏡による観察画像上で、プローブの先端を前記平面に接触させるステップと、第１の顕微鏡による観察画像上で測長した見かけの距離と第１の顕微鏡の姿勢情報を用いて第１の高さ距離を算出するステップと、第２の顕微鏡による観察画像上で測長した見かけの距離と第２の顕微鏡の姿勢情報を用いて第２の高さ距離を算出するステップと、第１の高さ距離と第２の高さ距離が等しくなるようにプローブの先端を前記平面上に移動させるステップとを含む。 According to still another aspect, the first microscope and the second microscope both have an optical axis that does not coincide with a driving direction when driving the probe toward the sample, and includes the optical axis of the first microscope. The plane perpendicular to the sample surface and the plane that includes the optical axis of the second microscope and perpendicular to the sample surface are aligned with each other, and the second step is performed on the observation image by the first or second microscope, A step of bringing the tip of the probe into contact with the plane; a step of calculating a first height distance using an apparent distance measured on an observation image by the first microscope and posture information of the first microscope; Calculating the second height distance using the apparent distance measured on the observation image by the second microscope and the posture information of the second microscope; the first height distance and the second height; Move the tip of the probe on the plane so that the distances are equal To and a step.

本発明によれば、顕微鏡の向きや配置に関わらず、複数の顕微鏡の観察画像をもとにプローブと試料の三次元的位置配置を得、プローブから試料までの距離を正確に測ることができる。また、プローブと試料との距離に応じたプローブ速度が設定できるため、短時間最適なプローブ速度でプローブを試料に接近又は接触させることが可能となる。 According to the present invention, a three-dimensional position arrangement of a probe and a sample can be obtained based on observation images of a plurality of microscopes regardless of the orientation and arrangement of the microscope, and the distance from the probe to the sample can be accurately measured. . Further, since the probe speed can be set according to the distance between the probe and the sample, the probe can be brought close to or brought into contact with the sample at an optimum probe speed for a short time.

以下、図面を参照して本発明の実施の形態を説明する。理解を容易にするために、以下の図において、同等の部材には同じ符号を付して説明する。プローブの位置や数は任意であるが、以下では説明を簡単にするためプローブの数は１つとして説明する。また、各実施の形態において、顕微鏡１と顕微鏡２の組み合わせは任意であり、例えば顕微鏡１を走査型電子顕微鏡（ＳＥＭ）、顕微鏡２を集束イオンビーム装置（ＦＩＢ）とすることができるが、それに限らず、例えば顕微鏡１をＦＩＢ、レーザー顕微鏡又は光学顕微鏡とし、顕微鏡２をＳＥＭ、レーザー顕微鏡又は光学顕微鏡とすることもできる。 Embodiments of the present invention will be described below with reference to the drawings. In order to facilitate understanding, the same reference numerals are given to the same members in the following drawings. The position and number of the probes are arbitrary, but in the following description, the number of probes is assumed to be one for the sake of simplicity. In each embodiment, the combination of the microscope 1 and the microscope 2 is arbitrary. For example, the microscope 1 can be a scanning electron microscope (SEM) and the microscope 2 can be a focused ion beam device (FIB). For example, the microscope 1 may be an FIB, laser microscope, or optical microscope, and the microscope 2 may be an SEM, laser microscope, or optical microscope.

［実施形態１］
図１は、本発明によるプローブ付き顕微鏡の一例を示す概念図である。試料６は試料台に載置されて移動可能である。図１に示した通り、顕微鏡１は試料面に対して垂直方向（Ｚ方向）に位置し、顕微鏡２は試料面からθの角度に位置しているとする。ここでは、プローブ３の先端を試料６の部位７に接触させる方法について説明する。プローブ３の先端を試料６の部位７に接触させる操作は、プローブ３を試料６に対して垂直方向上方から接近させることにより行う。つまり、本例のプローブ付き顕微鏡は、プローブ３を試料６に接触させる時にプローブ３を移動させる方向（Ｚ方向）と顕微鏡１の光軸とが一致している例である。 [Embodiment 1]
FIG. 1 is a conceptual diagram showing an example of a microscope with a probe according to the present invention. The sample 6 is mounted on the sample stage and is movable. As shown in FIG. 1, it is assumed that the microscope 1 is positioned in the direction perpendicular to the sample surface (Z direction), and the microscope 2 is positioned at an angle θ from the sample surface. Here, a method of bringing the tip of the probe 3 into contact with the part 7 of the sample 6 will be described. The operation of bringing the tip of the probe 3 into contact with the portion 7 of the sample 6 is performed by bringing the probe 3 closer to the sample 6 from above in the vertical direction. In other words, the microscope with a probe of this example is an example in which the direction (Z direction) in which the probe 3 is moved when the probe 3 is brought into contact with the sample 6 coincides with the optical axis of the microscope 1.

顕微鏡１がＳＥＭで、顕微鏡２がＦＩＢである場合、ＳＥＭを使用して信号検出器４で得た２次電子や反射電子などのアナログ情報は、アナログ信号線５を通り、Ａ／Ｄ変換部９でデジタル変換される。このデジタル変換されたデータを画像表示器１１に取り込み２次元画像とする。この画像を以下ＳＥＭ像と呼ぶ。また、ＦＩＢからも同様な方法で２次元画像を取得する。この画像を以下ＳＩＭ像と呼ぶ。ＳＥＭ像とＳＩＭ像を取得する際は共に信号検出器４を用いる。例えば、ＳＥＭ像からＳＩＭ像に切り替える際は、ＳＥＭからの電子ビーム照射を停止し、ＦＩＢからのイオンビーム照射を開始することで、ＳＩＭ像に切り替わる。 When the microscope 1 is an SEM and the microscope 2 is an FIB, analog information such as secondary electrons and reflected electrons obtained by the signal detector 4 using the SEM passes through the analog signal line 5 and is an A / D converter. 9 for digital conversion. This digitally converted data is taken into the image display 11 to obtain a two-dimensional image. This image is hereinafter referred to as an SEM image. Also, a two-dimensional image is acquired from the FIB by the same method. This image is hereinafter referred to as a SIM image. When acquiring the SEM image and the SIM image, the signal detector 4 is used. For example, when switching from a SEM image to a SIM image, the electron beam irradiation from the SEM is stopped, and the ion beam irradiation from the FIB is started to switch to the SIM image.

本実施形態では、顕微鏡２で得られた画像を用いて、プローブ３の先端８から、プローブ３を接触させたい試料６の部位７までの見かけの長さＬを測長する。測長は、画像表示器１１で得られた画像を解析することで行う。また、この測長は測長処理部１０にて行う。この測長値のデータ処理やデータ蓄積は測長データ処理部１２にて行う。また、プローブ速度はプローブ駆動コントローラ１３で決定し、そのプローブ駆動速度をもとに、プローブ駆動機構１４にてプローブ３を駆動する。 In the present embodiment, the apparent length L from the tip 8 of the probe 3 to the site 7 of the sample 6 to be contacted with the probe 3 is measured using the image obtained by the microscope 2. The length measurement is performed by analyzing the image obtained by the image display 11. The length measurement is performed by the length measurement processing unit 10. This length measurement data processing and data accumulation are performed by the length measurement data processing unit 12. The probe speed is determined by the probe drive controller 13, and the probe 3 is driven by the probe drive mechanism 14 based on the probe drive speed.

以下、プローブ駆動前に行う操作方法の詳細を示す。まず、図２に示すように、顕微鏡１の画像を用いて、試料部位７が観察画像の中心位置１５にくるように試料台位置や顕微鏡１を調整する。この結果、顕微鏡１の画像は、最初例えば図２（ａ）のように中心位置１５から外れていた試料部位７が、図２（ｂ）に示すように観察画像の中心位置１５に位置するようになる。この操作により、顕微鏡１の倍率を拡大しても縮小しても、顕微鏡１の画像中心位置１５に接触させたい試料部位７が位置していることになる。 Details of the operation method performed before driving the probe will be described below. First, as shown in FIG. 2, using the image of the microscope 1, the position of the sample stage and the microscope 1 are adjusted so that the sample portion 7 is at the center position 15 of the observation image. As a result, the image of the microscope 1 is such that the sample portion 7 that initially deviates from the center position 15 as shown in FIG. 2A, for example, is positioned at the center position 15 of the observation image as shown in FIG. become. By this operation, the sample portion 7 to be brought into contact with the image center position 15 of the microscope 1 is positioned regardless of whether the magnification of the microscope 1 is enlarged or reduced.

次に、顕微鏡１を用いて、図３に示すように、観察画像上にプローブ３とプローブ先端８を映し出す。図３（ａ）のようにプローブ先端８を画像で確認できたら、図３（ｂ）のように、プローブ先端８が観察画像の中心位置１５に位置するように、プローブ３をＸＹ方向に駆動する。この操作により、プローブ先端８が試料部位７の真上に移動したことになる。 Next, the probe 3 and the probe tip 8 are projected on the observation image using the microscope 1 as shown in FIG. When the probe tip 8 can be confirmed by an image as shown in FIG. 3A, the probe 3 is driven in the XY directions so that the probe tip 8 is located at the center position 15 of the observation image as shown in FIG. 3B. To do. By this operation, the probe tip 8 has moved directly above the sample portion 7.

図４のフローチャートにより、プローブ先端８を画像中心１５へ自動駆動する方法を説明する。まず、顕微鏡１の視野内にプローブ先端８が入るように調整し、プローブ先端８を観察する（Ｓ１１）。次に、顕微鏡１の画像にてプローブ先端８を画像認識し（Ｓ１２）、図３（ａ）に示すように、画像中心位置座標（０，０）からのずれ（Ｘ_１，Ｙ_１）を測定する（Ｓ１３）。次に、そのずれ（Ｘ_１，Ｙ_１）の分、プローブ駆動機構１４にてプローブ３を駆動する（Ｓ１４）。このように、プローブ先端８を自動画像認識し、画像中心に対するプローブ先端８の位置を測定することにより、画像中心へプローブ先端８を自動駆動することが可能である。 A method of automatically driving the probe tip 8 to the image center 15 will be described with reference to the flowchart of FIG. First, adjustment is made so that the probe tip 8 enters the field of view of the microscope 1, and the probe tip 8 is observed (S11). Next, the probe tip 8 is image-recognized from the image of the microscope 1 (S12), and the deviation (X ₁ , Y ₁ ) from the image center position coordinate (0, 0) as shown in FIG. Measure (S13). Next, the probe 3 is driven by the probe driving mechanism 14 by the deviation (X ₁ , Y ₁ ) (S14). As described above, by automatically recognizing the probe tip 8 and measuring the position of the probe tip 8 with respect to the image center, the probe tip 8 can be automatically driven to the image center.

以下、プローブ駆動開始から接触直前までのプローブ駆動方法を説明する。画像表示器１１に表示する画像を顕微鏡２の画像に切り替える。試料部位７が画像中心に位置するように顕微鏡２を調整すると、図５（ａ）に示すように、プローブ先端８が画像中心縦軸１６に上にある画像が取得できる。この画像からプローブ先端８と試料部位７との見かけの距離の測長を行う。この距離をＬ_１とすると、図６に示した関係から、プローブ先端８と試料部位７の実際の高さ方向の距離Ｚ_１は、次式（１）のように求まる。 Hereinafter, a probe driving method from the start of probe driving to immediately before contact will be described. The image displayed on the image display 11 is switched to the image of the microscope 2. When the microscope 2 is adjusted so that the sample region 7 is positioned at the center of the image, an image with the probe tip 8 on the image center vertical axis 16 can be acquired as shown in FIG. From this image, the apparent distance between the probe tip 8 and the sample portion 7 is measured. When this distance is L ₁ , the distance Z ₁ in the actual height direction between the probe tip 8 and the sample portion 7 is obtained from the relationship shown in FIG.

Ｚ_１＝Ｌ_１／cosθ （１） Z ₁ = L ₁ / cos θ (1)

この式（１）の計算は測長データ処理部１２にて行う。算出した高さ方向の距離Ｚ_１のデータをプローブ駆動コントローラ１３に送る。プローブ駆動コントローラ１３にはＺのデータに対応したプローブ駆動速度ｖが設定されている。例えば、プローブ先端８と試料部位７との実際の高さ方向の距離Ｚが１０μｍ〜１００μｍの時はプローブ駆動速度を１０μｍ／ｓに設定し、プローブ先端８と試料部位７との高さ方向の距離が１０μｍ〜１μｍの時はプローブ駆動速度を１μｍ／ｓに設定する。このように、プローブ駆動速度ｖを高さ方向の距離Ｚに応じて何段階かに分けて予めプローブ駆動コントローラ１３に登録しておく。この複数のプローブ駆動速度の登録により、プローブが試料表面から遠いときは速い速度で接近させ、試料表面に近づくに従って速度を緩めて接近させることができ、プローブ３を試料に急激に衝突させることなく、プローブ先端を試料に自動的に接近させることが可能となる。 The calculation of equation (1) is performed by the length measurement data processing unit 12. Send the calculated height direction of the distance Z ₁ data to the probe drive controller 13. The probe drive controller 13 is set with a probe drive speed v corresponding to the Z data. For example, when the distance Z in the actual height direction between the probe tip 8 and the sample portion 7 is 10 μm to 100 μm, the probe driving speed is set to 10 μm / s, and the height between the probe tip 8 and the sample portion 7 in the height direction is set. When the distance is 10 μm to 1 μm, the probe driving speed is set to 1 μm / s. Thus, the probe drive speed v is registered in advance in the probe drive controller 13 in several stages according to the distance Z in the height direction. By registering the plurality of probe driving speeds, when the probe is far from the sample surface, the probe can be approached at a high speed, and the probe 3 can be approached at a reduced speed as it approaches the sample surface, without causing the probe 3 to suddenly collide with the sample. It becomes possible to automatically bring the probe tip close to the sample.

図７は、プローブ駆動開始後、プローブ駆動速度が設定可能な最低値に設定されるまでの処理を示すフローチャートである。まず、測定した高さ方向の距離Ｚ_１に対応したプローブ駆動速度ｖ_１の情報をプローブ駆動機構部１４に送り、プローブ高さ方向（Ｚ方向）下方への駆動を開始する（Ｓ２１）。そのプローブ駆動速度ｖの情報は測長データ処理部１２にも送られ、測長データ処理部１２にてプローブの下降速度を常に監視する。Ｚ方向下方へのプローブ駆動開始後は、プローブ先端８と試料部位７との見かけの距離Ｌを周期的に自動測長する。測定周期はＴ［ｓ］とする。すなわち、顕微鏡２を用いてプローブ先端８と試料部位７との間の見かけの距離Ｌ_ｉを測定する（Ｓ２２）。測長データを測長データ処理部１２に保存し（Ｓ２３）、その後、測長データ処理部１２で高さ方向の距離Ｚを算出する（Ｓ２４）。距離Ｚのデータはプローブ駆動コントローラ１３に渡され、プローブ駆動コントローラ１３では距離Ｚに対応した下降速度ｖを決定する（Ｓ２５）。決定された速度ｖのデータは測長データ処理部１２に送信される（Ｓ２６）。次に、決定された速度ｖは最低速度かどうか判定し（Ｓ２７）、最低速度でない場合には決定された速度ｖでプローブ３を下降させる（Ｓ２８）。その後、時間Ｔ［ｓ］が経過すると、ｉを１だけインクリメントして見かけの距離Ｌｉを測長し（Ｓ２９）、ステップ２３に戻る。 FIG. 7 is a flowchart showing processing after the probe driving is started until the probe driving speed is set to a settable minimum value. First, information on the probe drive speed v ₁ corresponding to the measured distance Z ₁ in the height direction is sent to the probe drive mechanism 14 to start driving downward in the probe height direction (Z direction) (S21). Information on the probe driving speed v is also sent to the length measurement data processing unit 12, and the length measurement data processing unit 12 always monitors the descending speed of the probe. After starting driving the probe downward in the Z direction, the apparent distance L between the probe tip 8 and the sample portion 7 is automatically measured periodically. The measurement cycle is T [s]. That is, to measure the distance L _i apparent between the probe tip 8 and the sample site 7 by using the microscope 2 (S22). The length measurement data is stored in the length measurement data processing unit 12 (S23), and then the distance Z in the height direction is calculated by the length measurement data processing unit 12 (S24). The data of the distance Z is transferred to the probe drive controller 13, and the probe drive controller 13 determines the descending speed v corresponding to the distance Z (S25). The data of the determined speed v is transmitted to the length measurement data processing unit 12 (S26). Next, it is determined whether or not the determined speed v is the minimum speed (S27). If the determined speed v is not the minimum speed, the probe 3 is lowered at the determined speed v (S28). Thereafter, when the time T [s] has elapsed, i is incremented by 1 to measure the apparent distance Li (S29), and the process returns to step 23.

図７に示した処理例では、ステップ２８とステップ３０の間のタイミングで、観察画像を顕微鏡１の画像に切り替える。顕微鏡１によって試料の垂直上方からプローブ先端８と試料部位７の位置関係を観察した時、図８（ａ）のようにプローブ先端８が画像中心点１５からずれて観察された場合は、図８（ｂ）のようにプローブ先端８を画像中心点１５に合わせ直す。なお、プローブ先端と画像中心点１５との位置関係を確認するために観察画像を顕微鏡１の画像に切り替えるタイミングや、回数は任意であってよい。 In the processing example shown in FIG. 7, the observation image is switched to the image of the microscope 1 at the timing between step 28 and step 30. When the positional relationship between the probe tip 8 and the sample part 7 is observed from above the sample with the microscope 1, the probe tip 8 is observed as being shifted from the image center point 15 as shown in FIG. The probe tip 8 is adjusted to the image center point 15 as shown in FIG. In addition, in order to confirm the positional relationship between the probe tip and the image center point 15, the timing and the number of times of switching the observation image to the image of the microscope 1 may be arbitrary.

プローブ先端８とプローブ先端７との見かけの距離Ｌによっては、図５に示すように、顕微鏡２の倍率を拡大して距離Ｌの測長を行ってもよい。例として、図５（ａ）にｉ回目に測定した測長データＬ_ｉを倍率×１０００で、図５（ｂ）に（ｉ＋１）回目に測定した測長データＬ_ｉ＋１を倍率×２０００で、図５（ｃ）に（ｉ＋２）回目に測定した測長データＬ_ｉ＋２の測定を倍率×３０００で行った測定例をそれぞれ示した。このように、倍率を上げて観察を行うことで、より精度の高い測長が可能となる。周期的に測定した測長データＬ_ｉは、そのつど測長データ処理部１２に保管する。また、測長の際はプローブ駆動を停止してもよいし、プローブ駆動を行いながら測長してもよい。 Depending on the apparent distance L between the probe tip 8 and the probe tip 7, as shown in FIG. 5, the magnification of the microscope 2 may be enlarged to measure the distance L. As an example, FIG. 5A shows the measurement data L _i measured for the i th time at a magnification of × 1000, and FIG. 5B shows the measurement data L _{i + 1} measured for the (i + 1) th measurement at a magnification of × 2000. 5 (c) shows measurement examples in which the measurement data L _{i + 2} measured at the (i + 2) th time was measured at a magnification of × 3000. In this way, by performing observation while increasing the magnification, length measurement with higher accuracy becomes possible. The length measurement data L _i measured periodically is stored in the length measurement data processing unit 12 each time. Further, the probe drive may be stopped during the length measurement, or the length may be measured while performing the probe drive.

次に、プローブ先端と試料との接触を自動検知する方法に関して以下に説明する。図９は、プローブ接触検知方法を示すフローチャートである。本実施形態では、プローブの高さ方向の駆動速度は何段階かに分かれているとする。この何段階かに分かれている駆動速度の設定値の中で、これ以下の速度には設定することはない最低速度ｖ_ｍｉｎになった時、次式（２）を満たすかどうかを測長データ処理部１２で確認する（Ｓ３１）。 Next, a method for automatically detecting contact between the probe tip and the sample will be described below. FIG. 9 is a flowchart showing a probe contact detection method. In the present embodiment, it is assumed that the driving speed in the height direction of the probe is divided into several stages. Of the set values of the driving speed divided into several stages, the length measurement data indicates whether or not the following equation (2) is satisfied when the minimum speed v _min that is not set to a speed lower than this is reached. Confirmation is made by the processing unit 12 (S31).

｜（ｖ_ｍｉｎ×Ｔ）−（Ｚ_ｉ−１−Ｚ_ｉ）｜≦α （２） | (V _min × T) − (Z _i−1 −Z _i ) | ≦ α (2)

ここで、Ｔ［ｓ］は測長を行う時間間隔の周期であり、Ｚ_ｉ−１は（ｉ−１）回目に測定した測長値で、Ｚ_ｉはｉ回目に測定した測長値である。また、測長の測定誤差を考慮し、任意の定数αを計算にいれる必要がある。プローブ先端８と試料部位７が接触していないときは式（２）が成立するのでプローブを駆動し続け（Ｓ３２）、再度Ｔ［ｓ］後にプローブ先端８と試料部位７との距離Ｚを測長する（Ｓ３３）。プローブ先端８が試料に接触した際は、式（２）が成立しなくなるので、この時にプローブ高さ方向の駆動を自動停止させる（Ｓ３５）。このような自動接触検知により、試料やプローブの損傷を最小にしてプローブ先端を試料部位７に接触させることが可能となる。 Here, T [s] is a period of a time interval for measuring length, Z _i-1 is a measured value measured at the (i-1) th time, and Z _i is a measured value measured at the i-th time. is there. In addition, it is necessary to calculate an arbitrary constant α in consideration of the measurement error of the length measurement. When the probe tip 8 and the sample portion 7 are not in contact with each other, the equation (2) is satisfied, so that the probe continues to be driven (S32), and the distance Z between the probe tip 8 and the sample portion 7 is measured again after T [s]. Increase (S33). When the probe tip 8 comes into contact with the sample, the equation (2) is not established, and at this time, the driving in the probe height direction is automatically stopped (S35). Such automatic contact detection makes it possible to bring the tip of the probe into contact with the sample portion 7 with minimal damage to the sample and the probe.

この接触検知方法と併用して、従来からプローブと試料との接触検知に用いられている接触抵抗の測定や試料からプローブに流れる電流の測定などの接触検知を行ってもよい。 In combination with this contact detection method, contact detection such as measurement of contact resistance conventionally used for contact detection between the probe and the sample or measurement of current flowing from the sample to the probe may be performed.

［実施形態２］
図１０及び図１１は、本発明によるプローブ付き顕微鏡の他の例を示す概念図である。図１０の側面図に模式的に示すように、顕微鏡１は試料面からωの角度に位置し、顕微鏡２は試料面からθの角度に位置する。また、図１１の上面図に示すように、顕微鏡１の光軸を通り試料面に垂直な平面１７と、顕微鏡２の光軸を通り試料面に垂直な平面１６が等しくない時を考えるものとする。一例として顕微鏡１はＳＥＭ、顕微鏡２はＦＩＢとすることができる。ここで、図１０及び図１１には、機器の向きや詳細に幾分の相違があるが、それは説明を理解しやすくするためのものであり、本質的なものではない。また、Ｘ軸、Ｙ軸、Ｚ軸を図１０、図１１のように規定する。 [Embodiment 2]
10 and 11 are conceptual diagrams showing other examples of the microscope with a probe according to the present invention. As schematically shown in the side view of FIG. 10, the microscope 1 is located at an angle ω from the sample surface, and the microscope 2 is located at an angle θ from the sample surface. Further, as shown in the top view of FIG. 11, a case where a plane 17 passing through the optical axis of the microscope 1 and perpendicular to the sample surface is not equal to a plane 16 passing through the optical axis of the microscope 2 and perpendicular to the sample surface is considered. To do. As an example, the microscope 1 can be an SEM and the microscope 2 can be an FIB. Here, although there are some differences in the orientation and details of the devices in FIGS. 10 and 11, this is for easy understanding of the description and is not essential. Further, the X axis, the Y axis, and the Z axis are defined as shown in FIGS.

プローブ３の先端を試料６の部位７に接触させる際は、プローブ３を試料６にＺ方向上方から接近させる。つまり、本例のプローブ付き顕微鏡は、プローブ３を試料６に接触させる時にプローブ３を移動させる方向（Ｚ方向）が、顕微鏡１の光軸とも顕微鏡２の光軸とも一致しておらず、かつ、顕微鏡１の光軸を通り試料面に垂直な平面１７と、顕微鏡２の光軸を通り試料面に垂直な平面１６が等しくない例である。ここでは、説明の都合上、顕微鏡１はＸ軸に沿って位置し、顕微鏡２はＹ軸に沿って位置していると仮定する。しかし、平面１６と平面１７が等しくない限りは、顕微鏡１と顕微鏡２がどの位置にあっても、以下の手順によってプローブ３を効率的に試料６に接近させ、試料上の目的とする部位７に緩やかに接触させることができる。 When the tip of the probe 3 is brought into contact with the portion 7 of the sample 6, the probe 3 is brought close to the sample 6 from above in the Z direction. That is, in the microscope with a probe of this example, the direction (Z direction) in which the probe 3 is moved when the probe 3 is brought into contact with the sample 6 does not match the optical axis of the microscope 1 and the optical axis of the microscope 2 and In this example, the plane 17 passing through the optical axis of the microscope 1 and perpendicular to the sample surface is not equal to the plane 16 passing through the optical axis of the microscope 2 and perpendicular to the sample surface. Here, for convenience of explanation, it is assumed that the microscope 1 is located along the X axis and the microscope 2 is located along the Y axis. However, as long as the plane 16 and the plane 17 are not equal, the probe 3 is effectively brought close to the sample 6 by the following procedure regardless of the position of the microscope 1 and the microscope 2, and the target portion 7 on the sample is obtained. Can be gently touched.

本実施形態は、試料部位７の直上にプローブ先端８を待ってくる方法が実施形態１と異なる。そこで、以下では実施形態１との相違を中心に説明するものとし、既述の構成要素、実施方法と同等の場合には実施形態１の説明を援用する。 The present embodiment is different from the first embodiment in the method of waiting for the probe tip 8 immediately above the sample portion 7. Therefore, in the following, differences from the first embodiment will be mainly described, and the description of the first embodiment is used in the case where it is equivalent to the above-described components and implementation methods.

まず初めに、両方の顕微鏡１，２の観察画像の画像中心位置１５に、接触させたい試料部位７が来るように試料台位置や顕微鏡１，２を調整する（図２）。次に、一方の顕微鏡１の画像に切り替え、プローブ３とプローブ先端８を観察画像上に映し出す。プローブ３とプローブ先端８の画像が確認できたら、図１２や図１４に示すようにプローブ３をＹ方向に駆動して、画像中心縦軸、つまりＸＺ平面１７にプローブ先端８を接触させる。この時のプローブの３次元的な概略位置を図１４に示す。図１４からわかるように、プローブ先端８は平面１７に接触箇所１８で接したことになる。この操作を自動的に行うには、実施形態１で説明したように、顕微鏡１の観察画像においてプローブ先端８の画像認識を行い、プローブ先端のＹ座標が０になるようにプローブ駆動を行えばよい。 First, the sample stage position and the microscopes 1 and 2 are adjusted so that the sample site 7 to be brought into contact with the image center position 15 of the observation images of both the microscopes 1 and 2 (FIG. 2). Next, the image is switched to the image of one microscope 1 and the probe 3 and the probe tip 8 are displayed on the observation image. When the images of the probe 3 and the probe tip 8 are confirmed, the probe 3 is driven in the Y direction as shown in FIGS. 12 and 14, and the probe tip 8 is brought into contact with the image center longitudinal axis, that is, the XZ plane 17. The three-dimensional approximate position of the probe at this time is shown in FIG. As can be seen from FIG. 14, the probe tip 8 is in contact with the flat surface 17 at the contact point 18. In order to perform this operation automatically, as described in the first embodiment, the probe tip 8 is recognized in the observation image of the microscope 1 and the probe is driven so that the Y coordinate of the probe tip is zero. Good.

次に、他方の顕微鏡２に切り替えて、プローブ３とプローブ先端８を観察画像上に映し出す。次に、図１３に示すようにプローブ３をＸ方向に駆動し、ＹＺ平面１６にプローブ先端８を接触させる。ただし、このプローブ駆動の際は、プローブ３をＹ方向に動作させないようにする。この時のプローブ位置を図１５に示す。図１５からわかるように、プローブ先端８がＹＺ平面１６に接触箇所１９で接したことになる。この操作を自動的に行うには、顕微鏡２の観察画像においてプローブ先端８の画像認識を行い、プローブ先端８のＸ座標が０になるようにプローブ駆動を行えばよい。これらの操作により、プローブ先端８がＹＺ平面１６とＸＺ平面１７が交わった線上に移動したことになる。このＹＺ平面１６とＸＺ平面１７が交わった線はＺ軸と等しいので、プローブ先端８は試料部位７の真上に移動したことになる。このように２つの顕微鏡１，２を切り替えて使用することで、プローブ３の先端８を正確に、且つ高速に試料部位７の直上に移動することが可能となる。 Next, switching to the other microscope 2, the probe 3 and the probe tip 8 are displayed on the observation image. Next, as shown in FIG. 13, the probe 3 is driven in the X direction to bring the probe tip 8 into contact with the YZ plane 16. However, the probe 3 is not operated in the Y direction when the probe is driven. The probe position at this time is shown in FIG. As can be seen from FIG. 15, the probe tip 8 is in contact with the YZ plane 16 at the contact point 19. In order to perform this operation automatically, it is only necessary to perform image recognition of the probe tip 8 in the observation image of the microscope 2 and drive the probe so that the X coordinate of the probe tip 8 becomes zero. By these operations, the probe tip 8 has moved to a line where the YZ plane 16 and the XZ plane 17 intersect. Since the line where the YZ plane 16 and the XZ plane 17 intersect is equal to the Z axis, the probe tip 8 has moved directly above the sample region 7. By switching between the two microscopes 1 and 2 in this way, it is possible to move the tip 8 of the probe 3 to the position immediately above the sample site 7 accurately and at high speed.

もし、２つの顕微鏡１，２を同時に使って異なる方向から観察した画像を２枚取得できる装置構成であるならば、上記プローブのＸＺ平面１６とＹＺ平面１７への接触は同時に行ってもよい。 If the apparatus is configured to be able to acquire two images observed from different directions using the two microscopes 1 and 2 simultaneously, the probe may contact the XZ plane 16 and the YZ plane 17 at the same time.

プローブ駆動開始からプローブ接触までの動作は、実施形態１と同様である。顕微鏡１の観察画像から測長したプローブ先端８と試料部位７との見かけの距離をＬ_１とすると、図６に示した関係から、プローブ先端８と試料部位７までの実際の高さ方向の距離Ｚは、次式（３）のように求まる。また、顕微鏡２の観察画像から測長したプローブ先端８と試料部位７との見かけの距離をＬ_２とすると、プローブ先端８と試料部位７までの実際の高さ方向の距離Ｚは、同様に次式（４）のように求まる。 The operation from the probe driving start to the probe contact is the same as that of the first embodiment. When the apparent distance of the probe tip 8 and the sample portion 7 that measurement from the observed image microscope 1 and L _1, from the relationship shown in FIG. 6, the actual height direction to the probe tip 8 and the sample site 7 The distance Z is obtained as in the following equation (3). Moreover, when the apparent distance of the probe tip 8 and the sample portion 7 that measurement from the observed image microscope 2 and L _2, the distance Z of the actual height direction to the probe tip 8 and the sample site 7 is likewise The following equation (4) is obtained.

Ｚ＝Ｌ_１／cosω （３）
Ｚ＝Ｌ_２／cosθ （４） Z = L ₁ / cosω (3)
_{Z = L 2 / cosθ (4} )

顕微鏡１又は顕微鏡２を用いて、周期的に試料部位７からプローブ先端８までの距離Ｚを測定し、図７にて説明したようにプローブ駆動の開始を行い、図９にて説明したようにしてプローブ先端と試料表面の接触を検知し、プローブの駆動停止を行う。 Using the microscope 1 or the microscope 2, the distance Z from the sample portion 7 to the probe tip 8 is periodically measured, and the probe driving is started as described in FIG. 7, and as described in FIG. The contact between the probe tip and the sample surface is detected, and the drive of the probe is stopped.

ただし、図１６や図１７に示すように、顕微鏡１や顕微鏡２の倍率を上げて画像を取得した際に、プローブ先端８が平面１７や平面１６からずれていることがあれば、プローブ３をＹ方向に駆動してプローブ先端８を平面１７に接触させ、あるいはプローブ３をＸ方向に駆動してプローブ先端８を平面１６に接触させる操作を行い、常にプローブ先端８が試料部位７の直上に位置するように移動する必要がある。 However, as shown in FIGS. 16 and 17, when the magnification of the microscope 1 or the microscope 2 is increased and an image is acquired, if the probe tip 8 is displaced from the plane 17 or the plane 16, the probe 3 is removed. Drive in the Y direction to bring the probe tip 8 into contact with the plane 17 or drive the probe 3 in the X direction to bring the probe tip 8 into contact with the plane 16 so that the probe tip 8 is always directly above the sample site 7. It is necessary to move so that it is located.

［実施形態３］
図１８及び図１９は、本発明によるプローブ付き顕微鏡の他の例を示す概念図である。本実施の形態では、図１８の側面図に示すように、顕微鏡１は試料面からの角度ωに位置し、顕微鏡２は試料面からの角度θに位置する。かつ、図１９の上面図に示すように、顕微鏡１の光軸を通り試料に垂直な平面と、顕微鏡２の光軸を通り試料に垂直な平面が等しい場合を考える。以下、この平面をＹＺ平面２０とする。一例として、顕微鏡１はＳＥＭ、顕微鏡２はＦＩＢとすることができる。 [Embodiment 3]
18 and 19 are conceptual diagrams showing other examples of the microscope with a probe according to the present invention. In the present embodiment, as shown in the side view of FIG. 18, the microscope 1 is located at an angle ω from the sample surface, and the microscope 2 is located at an angle θ from the sample surface. Further, as shown in the top view of FIG. 19, consider a case where a plane passing through the optical axis of the microscope 1 and perpendicular to the sample is equal to a plane passing through the optical axis of the microscope 2 and perpendicular to the sample. Hereinafter, this plane is referred to as a YZ plane 20. As an example, the microscope 1 can be an SEM and the microscope 2 can be an FIB.

本装置構成の場合、実施形態２で説明した平面１６と平面１７が相等しいために、プローブ位置の取得方法や、試料部位７の直上にプローブ先端８を移動させる方法が実施形態１や実施形態２とは異なる。以下に、プローブ位置の取得方法とプローブ移動方法を説明する。 In the case of this apparatus configuration, since the plane 16 and the plane 17 described in the second embodiment are the same, the probe position acquisition method and the method of moving the probe tip 8 directly above the sample site 7 are the first embodiment and the embodiment. Different from 2. Hereinafter, a method for acquiring the probe position and a method for moving the probe will be described.

まず始めに、２つの顕微鏡１，２の画像中心位置１５に接触させたい試料６の部位７が来るように、試料台位置や顕微鏡１，２を調整する（図２）。次に、一方の顕微鏡１からの画像に切り替え、図２０（ａ）に示すように、プローブ３とプローブ先端８を観察画像上に映し出す。次に、図２０（ｂ）に示すように、ＹＺ平面２０にプローブ先端８を接触させる。この時に、試料部位７とプローブ先端８との見かけの距離Ｌ_１の測定を行う。次に、測長データ処理部１２にてＬ_１／cosω計算を行い、その計算結果の実際の距離Ｚ_１を保存する。この時のプローブ３と顕微鏡１と試料６との位置関係を図２２に示した。 First, the position of the sample stage and the microscopes 1 and 2 are adjusted so that the portion 7 of the sample 6 to be brought into contact with the image center position 15 of the two microscopes 1 and 2 comes (FIG. 2). Next, the image is switched from one microscope 1 and the probe 3 and the probe tip 8 are displayed on the observation image as shown in FIG. Next, as shown in FIG. 20B, the probe tip 8 is brought into contact with the YZ plane 20. At this time, to measure the distance L ₁ of the apparent between the sample sites 7 and the tip of the probe 8. Next, the L _{1 /} cos .omega calculated by measuring the data processing unit 12 stores the actual distance Z ₁ of the calculation results. The positional relationship among the probe 3, the microscope 1 and the sample 6 at this time is shown in FIG.

次に、顕微鏡２に切り替えると、図２１のようにＹＺ平面２０にプローブ先端８が接触している像が観察される。これは、顕微鏡１の光軸を通り試料６に垂直な平面と、顕微鏡２の光軸を通り試料６に垂直な平面が、共にＹＺ平面２０であるためである。次に、プローブ先端８と試料部位７との見かけの距離Ｌ_２の測長を行う。このＬ_２データ値を用いて、測長データ処理部１２にてＬ_２／cosθ計算を行う。この計算結果の実際の距離Ｚ_２を保存する。この時のプローブ３と顕微鏡２と試料６の位置関係を図２３に示した。 Next, when switching to the microscope 2, an image in which the probe tip 8 is in contact with the YZ plane 20 is observed as shown in FIG. This is because the plane that passes through the optical axis of the microscope 1 and is perpendicular to the sample 6 and the plane that passes through the optical axis of the microscope 2 and is perpendicular to the sample 6 are both the YZ plane 20. Next, the measurement of the distance L ₂ of apparent the probe tip 8 and the sample site 7. Using this _{L 2} data values, it performs _{L 2} / cos [theta] calculated by measuring the data processing unit 12. To store the actual distance Z ₂ of the calculation result. The positional relationship among the probe 3, the microscope 2 and the sample 6 at this time is shown in FIG.

測長データ処理部１２にてＺ_１（＝Ｌ_１／cosω）とＺ_２（＝Ｌ_２／cosθ）の大小比較を行う。もし、Ｚ_１とＺ_２が異なれば、Ｚ_１（Ｌ_１／cosω）＝Ｚ_２（Ｌ_２／cosθ）が成立するようにプローブ駆動を行う。駆動を行う方向は、例えば、Ｚ_１＞Ｚ_２の時は顕微鏡１の方向に、また、Ｚ_１＜Ｚ_２の時は顕微鏡２の方向にプローブ３を駆動すればよい。また、２つの顕微鏡を同時に使って、２枚の画像を同時に取得できる装置構成であるならば、距離Ｌ_１とＬ_２の測定は同時に行ってもよい。 The length measurement data processing unit 12 compares Z ₁ (= L ₁ / cosω) and Z ₂ (= L ₂ / cos θ). If Z ₁ and Z ₂ are different, probe driving is performed so that Z ₁ (L ₁ / cosω) = Z ₂ (L ₂ / cos θ) is satisfied. For example, the probe 3 may be driven in the direction of the microscope 1 when Z ₁ > Z _{2 and} in the direction of the microscope 2 when Z ₁ <Z ₂ . Further, if the apparatus configuration is such that two images can be acquired simultaneously using two microscopes, the distances L ₁ and L ₂ may be measured simultaneously.

距離Ｚ_１とＺ_２が等しくなれば、図２４のように、プローブ先端８が試料６の部位７の直上に移動したことになる。このようにして２つの顕微鏡１，２を切り替えて使用することで、プローブ先端８を試料部位７の直上に移動することが可能となる。この後のプローブ駆動はＺ軸方向に駆動するだけでよい。 If the distances Z ₁ and Z ₂ are equal, the probe tip 8 has moved directly above the portion 7 of the sample 6 as shown in FIG. By switching between the two microscopes 1 and 2 in this way, the probe tip 8 can be moved directly above the sample site 7. Subsequent probe driving only needs to be performed in the Z-axis direction.

以下、プローブ駆動開始からプローブ接触までの動作は実施形態１と同様である。また、実施形態２のように顕微鏡１や顕微鏡２の倍率を上げて画像を取得した際に、プローブ先端８がＹＺ平面２０からずれることがあれば、顕微鏡１か顕微鏡２の一方の観察画像で図２０のようにプローブ位置を修正する必要がある。また、プローブ先端８を試料部位７の直上に移動した後は、プローブ先端８と試料部位７との距離Ｌを測長する顕微鏡は顕微鏡１でも顕微鏡２でもかまわない。 Hereinafter, the operation from the probe driving start to the probe contact is the same as that of the first embodiment. Moreover, if the probe tip 8 is displaced from the YZ plane 20 when an image is acquired by increasing the magnification of the microscope 1 or the microscope 2 as in the second embodiment, one of the observation images of the microscope 1 or the microscope 2 is used. It is necessary to correct the probe position as shown in FIG. Further, after moving the probe tip 8 directly above the sample portion 7, the microscope for measuring the distance L between the probe tip 8 and the sample portion 7 may be either the microscope 1 or the microscope 2.

［実施形態４］
上記で説明した３つの実施形態では、プローブを試料に接近させ、接触させることを目的としていた。本実施形態では、マイクロサンプリングなどで微小試料を摘出した後に，試料片を固定試料台に接近、接触させる際のプローブ駆動方法を示したものである。本実施形態での装置構成は実施形態１と同等（図１）であるとする。また、顕微鏡１はＳＥＭ、顕微鏡２はＦＩＢであるとする。 [Embodiment 4]
In the three embodiments described above, the purpose is to bring the probe close to and in contact with the sample. In the present embodiment, a probe driving method when a sample piece is brought close to and brought into contact with a fixed sample stage after extracting a micro sample by micro sampling or the like is shown. The apparatus configuration in this embodiment is assumed to be the same as that in the first embodiment (FIG. 1). The microscope 1 is an SEM, and the microscope 2 is an FIB.

プローブに接着された微小試料片を試料固定台に接近させ、接触を行う方法を以下に説明する。基本的な操作は実施形態１と同等である。実施形態１ではプローブ先端８と試料部位７との距離を測長していたが、本実施形態では、プローブ３に接着された微小試料片２２の試料固定台２１に接触させたい部位２３と試料固定台２１との距離を測長する点だけが異なる。そこで、以下では実施形態１との相違を中心に説明するものとし、既述の構成要素、実施方法と同等のものに対しては実施形態１での説明を援用する。 A method for bringing the minute sample piece adhered to the probe close to the sample fixing base and performing contact will be described below. The basic operation is the same as that of the first embodiment. In the first embodiment, the distance between the probe tip 8 and the sample portion 7 is measured, but in this embodiment, the portion 23 and the sample to be brought into contact with the sample fixing base 21 of the micro sample piece 22 bonded to the probe 3 are measured. The only difference is that the distance to the fixed base 21 is measured. Therefore, the following description will focus on the differences from the first embodiment, and the description of the first embodiment will be applied to the components and implementation methods equivalent to those already described.

最初に、試料６の切り出したい微小試料片２２の周囲及び底部にＦＩＢ２を用いて溝を加工し、微小試料片のごく一部だけが試料とつながっている状態にまで加工する。次に、実施形態１で説明したようにしてプローブ３を下降し、プローブ先端８を微小試料片２２の上部に接触させる。その後、公知の方法によってプローブ先端８を微小試料片２２の上部に接着する。プローブ先端８が微小試料片２２の上部に接着されたら、ＦＩＢ２によって微小試料片２２を試料６から完全に切り離す。図２５は、微小試料片２２がプローブ８の先端に接着されて試料６から切り離された状態を模式的に示している。 First, a groove is processed using FIB 2 at the periphery and the bottom of the micro sample piece 22 to be cut out of the sample 6, and only a very small part of the micro sample piece is connected to the sample. Next, the probe 3 is lowered as described in the first embodiment, and the probe tip 8 is brought into contact with the upper portion of the minute sample piece 22. Thereafter, the probe tip 8 is bonded to the upper portion of the micro sample piece 22 by a known method. When the probe tip 8 is bonded to the top of the micro sample piece 22, the micro sample piece 22 is completely separated from the sample 6 by FIB2. FIG. 25 schematically shows a state in which the micro sample piece 22 is bonded to the tip of the probe 8 and separated from the sample 6.

その後、図２６に示すように、プローブ３に接着された微小試料片２２を試料固定台２１に接近させて、試料固定台２１に接触させる。まず初めに、ＳＥＭ１とＦＩＢ２それぞれの観察画像の画像中心位置１５に試料固定台２１が来るように、試料固定台２１の位置やＳＥＭ１及びＦＩＢ２を調整する。次に、ＳＥＭ１を用いて、観察画像上にプローブ３と微小試料片２２を映し出す。微小試料片２２の形状は摘出方法によって異なるが、本実施形態の方法で摘出した微小試料片２２は、図２５のように下面が角度θに傾斜した形状を有する。プローブ３と摘出微小試料片２２を画像で確認したら、ＳＥＭ１の画像上で微小試料片２２が試料固定台２１の真上に来るようにプローブ３を駆動させる。 Thereafter, as shown in FIG. 26, the micro sample piece 22 bonded to the probe 3 is brought close to the sample fixing base 21 and brought into contact with the sample fixing base 21. First, the position of the sample fixing base 21 and SEM1 and FIB2 are adjusted so that the sample fixing base 21 comes to the image center position 15 of the observation images of SEM1 and FIB2. Next, the probe 3 and the minute sample piece 22 are projected on the observation image using the SEM 1. Although the shape of the micro sample piece 22 differs depending on the extraction method, the micro sample piece 22 extracted by the method of the present embodiment has a shape in which the lower surface is inclined at an angle θ as shown in FIG. When the probe 3 and the extracted micro sample piece 22 are confirmed with images, the probe 3 is driven so that the micro sample piece 22 is directly above the sample fixing base 21 on the image of the SEM 1.

顕微鏡をＦＩＢ２に切り替えると、図２６や図２７に示すように、微小試料片２２の試料固定台２１に接触させたい下端部位２３と、摘出微小試料片２２のＦＩＢ２に近い部位２４は同じ箇所に重なって観察される。これは図２５に示したように、角度θで微小試料を摘出しているので、角度θに傾斜したＦＩＢ２からの観察では、摘出微小試料片２２の下端部位２３とＦＩＢに近い側の部位２４は光軸方向に重なった箇所として観察されるからである。従って、図２７に示すように、ＦＩＢ２の観察画像上で微小試料片の部位２４と試料固定台２１との見かけの距離Ｌ_２を測定すれば、次式（５）によって接触させたい摘出微小試料部位２３と試料台との実際の距離Ｚが求まる。 When the microscope is switched to FIB2, as shown in FIG. 26 and FIG. 27, the lower end portion 23 to be brought into contact with the sample fixing base 21 of the minute sample piece 22 and the portion 24 near the FIB2 of the extracted minute sample piece 22 are in the same place. Overlapping is observed. As shown in FIG. 25, since the micro sample is extracted at an angle θ, in the observation from the FIB 2 inclined to the angle θ, the lower end portion 23 of the extracted micro sample piece 22 and the portion 24 on the side close to the FIB. This is because it is observed as a portion overlapping in the optical axis direction. Therefore, as shown in FIG. 27, if the apparent distance L2 between the portion 24 of the micro sample piece and the sample fixing base 21 is measured on the observation image of the FIB ₂ , the micro sample to be contacted by the following equation (5) The actual distance Z between the part 23 and the sample stage is obtained.

Ｚ＝Ｌ_２／cosω （５） Z = L ₂ / cosω (5)

以下、プローブ３の駆動開始から試料固定台２１に微小試料片２２を接触させるまでの動作は実施形態１と同様である。微小試料片２２の下端部位２３が試料固定台２１に接触したら、公知の方法によって微小試料片２２を試料固定台２１に固定する。その後、微小試料片２２からプローブ３を切り離し、必要に応じて試料固定台２１に固定された微小試料片２２に対しＦＩＢ２を用いた加工が行われる。 Hereinafter, the operation from the start of driving of the probe 3 to the contact of the minute sample piece 22 with the sample fixing base 21 is the same as that of the first embodiment. When the lower end portion 23 of the micro sample piece 22 contacts the sample fixing base 21, the micro sample piece 22 is fixed to the sample fixing base 21 by a known method. Thereafter, the probe 3 is separated from the micro sample piece 22, and processing using the FIB 2 is performed on the micro sample piece 22 fixed to the sample fixing base 21 as necessary.

実施形態１に係る装置構成を示す模式図である。1 is a schematic diagram illustrating an apparatus configuration according to Embodiment 1. FIG. 試料部位を画像中心に映し出す動作を示す顕微鏡像の模式図である。It is a schematic diagram of the microscope image which shows the operation | movement which projects a sample site | part to the image center. 試料部位の直上にプローブ先端を移動させる動作を示す顕微鏡１の像模式図である。It is an image schematic diagram of the microscope 1 which shows the operation | movement which moves a probe front-end | tip just above a sample site | part. プローブ先端を顕微鏡１の画像中心に駆動させるためのフローチャートを示す。3 is a flowchart for driving the probe tip to the image center of the microscope 1. プローブ先端を試料部位に接近させながら、画像倍率を上げて測長処理を行なっている際の顕微鏡２像の模式図である。It is a schematic diagram of two images of a microscope when length measurement processing is performed by increasing the image magnification while bringing the probe tip close to a sample site. 実施形態１に係る測長方法を示す模式図である。FIG. 3 is a schematic diagram illustrating a length measurement method according to the first embodiment. プローブ駆動開始後に、プローブ駆動速度が設定できる最低値になるまでのフローチャートを示す。The flowchart until a probe drive speed becomes the minimum value which can be set after a probe drive start is shown. プローブ先端が試料部位の直上になかった時に、プローブ先端を直上に移動させる動作を示す顕微鏡１像の模式図である。It is a schematic diagram of a microscope 1 image showing an operation of moving the probe tip directly above when the probe tip is not directly above the sample part. プローブ接触検知方法のフローチャートを示す。The flowchart of a probe contact detection method is shown. 実施形態２に係る装置構成を示す模式図の平面図である。FIG. 6 is a plan view of a schematic diagram illustrating a device configuration according to a second embodiment. 実施形態２に係る装置構成を示す模式図の上面図である。FIG. 4 is a top view of a schematic diagram illustrating a device configuration according to a second embodiment. プローブ先端をＸＺ平面に接触させる動作を示す顕微鏡１像の模式図である。It is a schematic diagram of a microscope 1 image showing the operation of bringing the probe tip into contact with the XZ plane. プローブ先端をＹＺ平面に接触させる動作を示す顕微鏡２像の模式図である。It is a schematic diagram of two microscope images showing an operation of bringing the probe tip into contact with the YZ plane. プローブ先端がＸＺ平面に接触した動作後の装置配置構成図である。It is an apparatus arrangement configuration diagram after the operation in which the probe tip contacts the XZ plane. プローブ先端がＹＺ平面に接触した動作後の装置配置構成図である。It is an apparatus arrangement configuration diagram after the operation in which the probe tip contacts the YZ plane. プローブ先端位置がＸＺ平面に接触していなかった時に、プローブ先端を移動させる動作を示す顕微鏡１像の模式図である。It is a schematic diagram of a microscope 1 image showing an operation of moving the probe tip when the probe tip position is not in contact with the XZ plane. プローブ先端がＹＺ平面に接触していなかった時に、プローブ先端を移動させる動作を示す顕微鏡２像の模式図である。It is a schematic diagram of two microscope images showing an operation of moving the probe tip when the probe tip is not in contact with the YZ plane. 実施形態３に係る装置構成を示す模式図の平面図である。It is a top view of the schematic diagram which shows the apparatus structure which concerns on Embodiment 3. FIG. 実施形態３に係る装置構成を示す模式図の上面図である。It is a top view of the schematic diagram which shows the apparatus structure which concerns on Embodiment 3. FIG. プローブ先端をＸＺ平面に接触させる動作を示す顕微鏡１像の模式図である。It is a schematic diagram of a microscope 1 image showing the operation of bringing the probe tip into contact with the XZ plane. プローブ先端とＸＺ平面との接触を示す顕微鏡１像の模式図である。It is a schematic diagram of 1 image of the microscope showing contact between the probe tip and the XZ plane. 実施形態３に係る測長方法を示す模式図である。10 is a schematic diagram illustrating a length measurement method according to Embodiment 3. FIG. 実施形態３に係る測長方法を示す模式図である。10 is a schematic diagram illustrating a length measurement method according to Embodiment 3. FIG. 実施形態３に係る測長方法を示す模式図である。10 is a schematic diagram illustrating a length measurement method according to Embodiment 3. FIG. 微小試料摘出後の模式図である。It is a schematic diagram after micro sample extraction. 実施形態４に係る測長方法を示す模式図であり、微小試料片と試料固定台を示した立体図である。FIG. 10 is a schematic diagram illustrating a length measurement method according to a fourth embodiment, and is a three-dimensional view illustrating a minute sample piece and a sample fixing base. 実施形態４に係る測長方法を示す模式図である。It is a schematic diagram which shows the length measuring method which concerns on Embodiment 4.

Explanation of symbols

１：顕微鏡（ＳＥＭ）、２：顕微鏡（ＦＩＢ）、３：プローブ、４：信号検出器、５：アナログ信号線、６：試料、７：プローブを接触させたい試料部位、８：プローブ先端、９：Ａ／Ｄ変換機、１０：測長処理部、１１：画像表示器、１２：測長データ処理部、１３：プローブ駆動コントローラ、１４：プローブ駆動機構、１５：画像中心点、１６：ＹＺ平面、１７：ＸＺ平面、１８：ＹＺ平面とプローブ先端８との接触箇所、１９：ＸＺ平面とプローブ先端８との接触箇所、２０：ＸＺ平面、２１：試料固定台、２２：摘出微小試料片、２３：試料固定台に接触する摘出微小試料部位 1: Microscope (SEM), 2: Microscope (FIB), 3: Probe, 4: Signal detector, 5: Analog signal line, 6: Sample, 7: Sample portion to be contacted with probe, 8: Probe tip, 9 : A / D converter, 10: Length measurement processing unit, 11: Image display, 12: Length measurement data processing unit, 13: Probe drive controller, 14: Probe drive mechanism, 15: Image center point, 16: YZ plane 17: XZ plane, 18: contact location between the YZ plane and the probe tip 8, 19: contact location between the XZ plane and the probe tip 8, 20: XZ plane, 21: sample fixing base, 22: extracted micro sample piece, 23: Extracted minute sample part in contact with sample fixing table

Claims

A first and a second microscope capable of observing substantially the same point of the sample;
A sample stage on which the sample is placed;
A mechanical probe;
A probe driving mechanism for driving the mechanical probe;
A length measurement processing unit for analyzing an observation image by a microscope and measuring an apparent distance between the probe and the sample;
Look including the measurement data processing unit to calculate the actual distance between the probe and the sample on the basis of the length value and the microscope and orientation information of the measurement by the measuring unit,
Measure the actual distance between the probe and the sample while driving the probe closer to the sample direction, and when the distance does not match the distance expected from the probe driving speed by the probe driving mechanism, A compound microscope with a probe, wherein driving of the probe by the probe driving mechanism is stopped .

The compound microscope with a probe according to claim 1, wherein the probe driving mechanism has a plurality of speeds according to an actual distance between the probe and the sample such that the driving speed becomes slower as the probe approaches the sample. The composite microscope with a probe is characterized in that the probe is driven in a direction to approach the sample by switching in a stepwise manner.

In a probe driving method for bringing the tip of a mechanical probe into contact with a reference point on a sample surface,
Using a first and a second microscope, a first step of adjusting the reference point so that it is at the center of the observation image by the first and second microscopes;
A second step of positioning the tip of the probe directly above the reference point;
A third step of measuring an apparent distance between the reference point and the tip of the probe on the observation image by the first microscope and / or the observation image by the second microscope;
A fourth step of calculating a height direction distance of the probe with respect to the reference point using the apparent distance and posture information of the first microscope and / or the second microscope;
A fifth step of driving the probe in a direction approaching the reference point;
When the actual distance between the tip of the probe and the reference point is measured while the probe is approaching the reference point, and the distance no longer matches the distance expected from the probe driving speed. And a sixth step of stopping the driving of the probe.

The probe driving method according to claim 3 ,
In the first microscope and the second microscope, the optical axis of the first microscope coincides with the driving direction when the probe is driven in the sample direction, and the optical axis of the second microscope is the driving direction. Is in a positional relationship that does not match
The second step comprises the step of positioning the tip of the probe at the center of the image observed by the first microscope,
The third step includes a step of measuring an apparent distance between the reference point and the tip of the probe from an image observed by the second microscope,
The probe driving method according to claim 4, wherein the fourth step includes a step of calculating a distance in the height direction using the apparent distance and posture information of the second microscope.

The probe driving method according to claim 3 ,
In both the first microscope and the second microscope, the optical axis does not coincide with the driving direction when the probe is driven in the sample direction, and includes the optical axis of the first microscope and is perpendicular to the sample surface. The first plane and the second plane including the optical axis of the second microscope and perpendicular to the sample surface are in a positional relationship, and
The second step includes a step of bringing a tip of the probe into contact with the first plane on an observation image obtained by the first microscope, and a step of placing the tip of the probe on the observation image obtained by the second microscope. Moving in a first plane to contact the second plane,
The third step includes a step of measuring an apparent distance between the reference point and the tip of the probe on the observation image by the first microscope or the observation image by the second microscope,
In the fourth step, the apparent distance measured on the observation image by the first microscope and the posture information of the first microscope are used, or the measurement is performed on the observation image by the second microscope. A probe driving method comprising the step of calculating a distance in the height direction using an apparent distance and posture information of the second microscope.

The probe driving method according to claim 3 ,
In both the first microscope and the second microscope, the optical axis does not coincide with the driving direction when the probe is driven in the sample direction, and includes the optical axis of the first microscope and is perpendicular to the sample surface. A plane and a plane that includes the optical axis of the second microscope and that is perpendicular to the sample surface are coincident with each other;
The second step includes a step of bringing the tip of the probe into contact with the plane on an observation image obtained by the first or second microscope, and an apparent distance measured on the observation image obtained by the first microscope. The step of calculating the first height distance using the posture information of the first microscope, the apparent distance measured on the observation image by the second microscope, and the posture information of the second microscope are used. Calculating a second height distance, and moving the probe tip onto the plane so that the first height distance is equal to the second height distance. A probe driving method.

4. The probe driving method according to claim 3 , wherein a plurality of speeds are set according to an actual distance between the probe tip and the reference point so that the drive speed becomes slower as the tip of the probe approaches the reference point. A probe driving method, wherein the probe is driven in a direction approaching the reference point by switching the speed stepwise.

Using a compound probe microscope having a mechanical probe, a microscope having an optical axis that coincides with a driving direction when the probe is driven in a sample direction, and a focused ion beam device having an optical axis that does not coincide with the driving direction In the probe driving method in which the sample piece extracted from the sample using the focused ion beam device and adhered to the tip of the probe is brought close to and brought into contact with the sample fixing table,
Adjusting the sample fixing base so as to come to the center of the observation image by the microscope and the center of the observation image by the focused ion beam device;
Positioning the sample piece at the center of an image observed by the microscope;
Measuring an apparent distance between the sample fixing base and the sample piece end from an observation image by the focused ion beam device;
Calculating a distance in a height direction of the sample piece with respect to the sample fixing table using the apparent distance and posture information of the focused ion beam device;
Driving the probe in a direction approaching the sample fixture;
The actual distance between the one end of the sample and the sample fixing base is measured while the probe is approaching the sample fixing base, and the distance does not coincide with the distance expected from the driving speed of the probe. And a step of stopping driving of the probe when the probe is driven.

9. The probe driving method according to claim 8 , wherein a plurality of speeds according to a distance in a height direction of the sample piece relative to the sample fixing base is set such that the driving speed becomes slower as the sample piece approaches the use fixing base. The probe is driven in a stepwise manner, and the probe is driven in a direction approaching the sample fixing base.