JPH0714537A - Measuring method by scanning electron microscope - Google Patents
Measuring method by scanning electron microscopeInfo
- Publication number
- JPH0714537A JPH0714537A JP15012893A JP15012893A JPH0714537A JP H0714537 A JPH0714537 A JP H0714537A JP 15012893 A JP15012893 A JP 15012893A JP 15012893 A JP15012893 A JP 15012893A JP H0714537 A JPH0714537 A JP H0714537A
- Authority
- JP
- Japan
- Prior art keywords
- image
- sample
- analysis
- electron microscope
- scanning electron
- 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.)
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、走査型電子顕微鏡によ
る計測方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring method using a scanning electron microscope.
【０００２】[0002]
【従来の技術】従来、走査型電子顕微鏡によりレジス
ト，ＳｉＯ2 などの非導電性材料表面を観察する場合に
は、電子ビームを照射したことにより材料表面に電荷が
蓄積する、いわゆるチャージアップが発生し、像観察が
困難になるという問題があった。特にレジストあるいは
ＳｉＯ2 の微細コンタクトホールパターンの場合には試
料表面の全面がチャージアップするため、パターンの識
別が非常に困難であった。2. Description of the Related Art Conventionally, when observing the surface of a non-conductive material such as a resist or SiO 2 with a scanning electron microscope, the so-called charge-up, which is the accumulation of charges on the material surface due to the irradiation of an electron beam, occurs. However, there is a problem that the image observation becomes difficult. In particular, in the case of a resist or a fine contact hole pattern of SiO 2 , the entire surface of the sample is charged up, and it is very difficult to identify the pattern.
【０００３】この表面チャージアップの問題を解決する
ため、二次電子放出利得が１となる加速電圧で観察する
低加速ＳＥＭ（スキャニング エレクトロン マイクロ
スコープ、Scaning Electron Microscope）が知られて
いる。また、特開平3−163736号公報に記載された発明
においては、走査型電子顕微鏡の試料室と試料交換室の
間に試料表面に導電性薄膜を蒸着するための試料処理室
を設けた構造としている。この発明によれば、試料処理
室で導電性薄膜を蒸着することにより、試料表面が試料
ホルダを介して接地電位に固定されるため、電子ビーム
を照射しても試料表面に電荷が蓄積されることが無く、
チャージアップが発生し易い非導電性材料表面の像観察
を容易にするものである。In order to solve this surface charge-up problem, a low acceleration SEM (Scanning Electron Microscope) for observing at an accelerating voltage at which the secondary electron emission gain is 1 is known. Further, in the invention described in JP-A-3-163736, as a structure provided with a sample processing chamber for depositing a conductive thin film on the sample surface between the sample chamber and the sample exchange chamber of the scanning electron microscope. There is. According to this invention, by depositing the conductive thin film in the sample processing chamber, the surface of the sample is fixed to the ground potential via the sample holder, so that charges are accumulated on the surface of the sample even when irradiated with an electron beam. Without
This facilitates image observation of the surface of the non-conductive material where charge-up is likely to occur.
【０００４】[0004]
【発明が解決しようとする課題】上記の従来技術におい
て、低加速ＳＥＭでは加速電圧を一定の値に固定して観
察するため、試料の表面材質の変化に伴う二次電子放出
利得の変化などにより完全にはチャージアップを防止で
きない。また、Ｘ線分析を行う際には、十分な分析感度
が得られる比較的高い加速電圧により行うため、チャー
ジアップを防止することができない。導電性薄膜蒸着法
は、走査型電子顕微鏡内での観察終了後に試料処理室で
蒸着した導電性薄膜のみを選択的に完全に除去すること
が不可能であり、試料を後の半導体製造工程に戻した際
に重金属汚染や配線材料相互の接触抵抗増加等の支障を
来すため、インライン評価には適用できないという問題
があった。In the above prior art, in the low acceleration SEM, the accelerating voltage is fixed at a constant value for observation, so that the secondary electron emission gain changes due to the change of the surface material of the sample. It cannot completely prevent charge-up. Further, when performing X-ray analysis, charge-up cannot be prevented because it is performed with a relatively high acceleration voltage that provides sufficient analysis sensitivity. The conductive thin film deposition method cannot selectively and completely remove only the conductive thin film deposited in the sample processing chamber after the observation in the scanning electron microscope is completed, and the sample can be used in the subsequent semiconductor manufacturing process. There is a problem that it cannot be applied to in-line evaluation because it causes heavy metal contamination and increases contact resistance between wiring materials when returned.
【０００５】本発明の目的は、非導電性材料表面でのチ
ャージアップを防止して像観察及びＸ線分析を容易にか
つ高感度に行うことができ、さらに観察終了後に試料を
半導体製造工程に戻すことのできるインライン評価が可
能な計測方法を提供することにある。It is an object of the present invention to prevent charge-up on the surface of a non-conductive material and to easily perform image observation and X-ray analysis with high sensitivity. It is to provide a measurement method that enables inline evaluation that can be returned.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するた
め、本発明は、像観察あるいはＸ線分析を行うべくパタ
ーンの位置決めの際に用いた加速電圧を、像観察あるい
はＸ線分析時には異なる加速電圧を切り替えて行う。In order to achieve the above object, the present invention uses an accelerating voltage used for positioning a pattern for image observation or X-ray analysis, which is different during image observation or X-ray analysis. Switch the voltage to perform.
【０００７】[0007]
【作用】本発明によれば、像観察あるいはＸ線分析を行
うべくパターンの位置決めを行う際に試料表面に蓄積し
た電荷を、像観察あるいはＸ線分析時に異なる加速電圧
に切り替えて反対極性の電荷を発生させ蓄積電荷を打ち
消すことにより、試料表面のチャージアップを防止でき
る。また、分析後の試料表面には異物，金属薄膜等が残
存しないため、試料を後の半導体製造工程に戻しても支
障を来すことが無く、インライン評価が可能となる。According to the present invention, the charges accumulated on the sample surface during pattern positioning for image observation or X-ray analysis are switched to different accelerating voltages during image observation or X-ray analysis, and charges of opposite polarity. By generating and canceling the accumulated charge, it is possible to prevent charge-up on the sample surface. In addition, since no foreign matter, metal thin film, etc. remain on the surface of the sample after analysis, in-line evaluation can be performed without any trouble even if the sample is returned to the subsequent semiconductor manufacturing process.
【０００８】[0008]
【実施例】（実施例 １）図１は、加速電圧と二次電子
放出利得の関係を示す。EXAMPLES Example 1 FIG. 1 shows the relationship between the acceleration voltage and the secondary electron emission gain.
【０００９】本実施例は、表面材料がレジストの微細コ
ンタクトホールパターンの底面を走査型電子顕微鏡によ
り分析する際に、まず、二次電子放出利得δ＞１の加速
電圧、例えば０.８ｋＶ を印加して分析点の位置決めを
行う。次に、二次電子放出利得δ＜１の加速電圧、例え
ば、２.０ｋＶ に切り替え、加速電圧を変化させた時に
生じる画像の移動及び焦点のずれを自動的に補正して分
析を行う方法である。In this embodiment, when a bottom surface of a fine contact hole pattern made of a resist whose surface material is a resist is analyzed by a scanning electron microscope, first, an accelerating voltage with a secondary electron emission gain δ> 1 is applied, for example, 0.8 kV. Then, the analysis point is positioned. Then, the acceleration voltage with secondary electron emission gain δ <1 is switched to, for example, 2.0 kV, and the movement and focus shift of the image that occurs when the acceleration voltage is changed are automatically corrected and analyzed. is there.
【００１０】ここで、図２を用いて自動画像移動補正機
構を説明する。電子銃１より照射した電子ビームをコン
デンサレンズ２及び対物レンズ４により試料６上に集束
させるビーム集光系と、電子ビームを偏向コイル３によ
り二次元的に走査するビーム走査系と、試料６表面から
放出される二次電子又は反射電子を検出し増幅する検出
増幅部７と、検出増幅部７からの検出信号を輝度信号と
して供給しＣＲＴ上に画像を表示する画像表示部８から
成る走査型電子顕微鏡において、まず、検出増幅部７か
らの検出信号を受けて画像の初期位置及び画像鮮明度を
画像処理部９で記憶する。The automatic image movement correction mechanism will be described with reference to FIG. A beam focusing system that focuses an electron beam emitted from the electron gun 1 onto a sample 6 by a condenser lens 2 and an objective lens 4, a beam scanning system that scans the electron beam two-dimensionally by a deflection coil 3, and the surface of the sample 6. Scanning type including a detection amplification unit 7 that detects and amplifies secondary electrons or backscattered electrons emitted from the display unit, and an image display unit 8 that supplies a detection signal from the detection amplification unit 7 as a luminance signal and displays an image on a CRT. In the electron microscope, first, the detection signal from the detection amplification unit 7 is received, and the initial position and image sharpness of the image are stored in the image processing unit 9.
【００１１】次に、上述のように加速電圧を切り替えた
際の画像のずれ量を画像処理部９で計算し、画像のずれ
を補正すべく画像ずれ量補正信号を画像移動補正部１０
に供給する。その後、画像移動補正部１０より画像ずれ
量補正信号に基づいて偏向コイル３を微動させ、画像を
初期位置に復元させる。その後、初期位置に復元した画
像の鮮明度を再度画像処理部９で記憶し、初期の画像鮮
明度と比較し、その補正量を信号として画像移動補正部
１０に供給する。その後、画像移動補正部１０より画像
鮮明度補正信号に基づいて対物レンズ４を制御し、画像
の焦点を初期状態に復元させる。Next, the image shift amount of the image when the acceleration voltage is switched as described above is calculated by the image processing unit 9, and the image shift amount correction signal is sent to the image movement correction unit 10 to correct the image shift.
Supply to. After that, the image movement correction unit 10 finely moves the deflection coil 3 based on the image shift amount correction signal to restore the image to the initial position. After that, the sharpness of the image restored to the initial position is stored again in the image processing unit 9, compared with the initial image sharpness, and the correction amount is supplied to the image movement correction unit 10 as a signal. Thereafter, the image movement correction unit 10 controls the objective lens 4 based on the image sharpness correction signal to restore the focus of the image to the initial state.
【００１２】なお、分析を行う際の加速電圧は、０.５
〜５.０ｋＶの範囲に設定することが望ましい。その理
由は、微細コンタクトホール内底面の計測対象材料より
蛍光Ｘ線を十分に励起できること、高感度な分析を行う
ためには計測対象材料から放射される特性Ｘ線エネルギ
の１〜１０倍の加速電圧が必要であること、及び試料を
傾斜させて分析を行う場合には、図１に示すように、試
料傾斜角度が大きいほど二次電子放出利得δ＜１となる
加速電圧が高加速電圧側にシフトするためである。The accelerating voltage for the analysis is 0.5
It is desirable to set in the range of up to 5.0 kV. The reason is that fluorescent X-rays can be sufficiently excited from the measurement target material on the bottom surface inside the fine contact hole, and in order to perform highly sensitive analysis, the acceleration is 1 to 10 times the characteristic X-ray energy emitted from the measurement target material. When a voltage is required and when the sample is tilted for analysis, as shown in FIG. 1, the accelerating voltage at which the secondary electron emission gain δ <1 becomes larger as the sample tilt angle becomes higher is on the high accelerating voltage side. To shift to.
【００１３】上述した分析方法によれば、０.８ｋＶ の
加速電圧を印加した場合のレジスト表面から放出される
二次電子放出利得は１よりも大きいため、電子ビームを
走査した領域の試料表面には正電荷が蓄積される。その
後、２.０ｋＶ の加速電圧を印加すると、二次電子放出
利得は１よりも小さいためレジスト表面には負電荷が発
生し、両者の電荷が打ち消し合うことによりレジスト表
面でのチャージアップを防止でき、微細コンタクトホー
ルパターンの分析を容易に行うことができる。また、分
析後の試料表面には異物，金属薄膜等が残存しないた
め、試料を後の半導体製造工程に戻しても支障を来すこ
とが無く、インライン評価が可能である。さらに、本実
施例で示した自動画像移動補正機構によれば、加速電圧
を変化させた時に生じる画像の移動及び焦点のずれを速
やかに自動的に補正できるため、像観察時間を大幅に短
縮できる。According to the above-described analysis method, the secondary electron emission gain emitted from the resist surface when an accelerating voltage of 0.8 kV is applied is larger than 1, so that the sample surface in the region scanned with the electron beam is Accumulates a positive charge. Then, when an accelerating voltage of 2.0 kV is applied, the secondary electron emission gain is smaller than 1, so negative charges are generated on the resist surface, and the charges on both sides cancel each other out, preventing charge-up on the resist surface. Therefore, it is possible to easily analyze the fine contact hole pattern. Further, since no foreign matter, metal thin film, etc. remain on the surface of the sample after the analysis, in-line evaluation is possible without causing any trouble even if the sample is returned to the subsequent semiconductor manufacturing process. Further, according to the automatic image movement correction mechanism shown in the present embodiment, the movement of the image and the shift of the focus which occur when the accelerating voltage is changed can be quickly and automatically corrected, so that the image observation time can be greatly shortened. .
【００１４】（実施例 ２）第一の実施例と同様に、図
１を用いて本実施例を説明する。(Embodiment 2) This embodiment will be described with reference to FIG. 1 as in the first embodiment.
【００１５】本実施例では、表面材料がレジストであり
構造が微細コンタクトホールパターンの試料を走査型電
子顕微鏡により像観察及びホール底部のＸ線分析を行う
際に、二次電子放出利得δ＝１となる加速電圧Ｖ１を自
動的に決定し、像観察及びＸ線分析を行うべきコンタク
トホール部の位置決めを行う方法である。In this embodiment, the secondary electron emission gain δ = 1 when performing image observation and X-ray analysis of the bottom of the hole of a sample having a resist as a surface material and a fine contact hole pattern structure. This is a method of automatically determining the accelerating voltage V1 to be used and positioning the contact hole portion where image observation and X-ray analysis should be performed.
【００１６】ここで、二次電子放出利得δが１となる加
速電圧Ｖ１の決定手法を図３を用いて説明する。まず、
任意の加速電圧Ｖａを用いて任意の倍率で一定時間試料
上に電子ビームを走査し、その後低倍率に切り替えて、
低倍率領域の輝度と比較して初めに電子ビームを走査し
た高倍率領域内の輝度の明暗により、二次電子放出利得
δ＝１，＞１，＜１の三つの状態を判別する。低倍率に
切り替えた直後の低倍率領域は電子ビーム照射を受けて
試料表面にはごくわずかに正電荷が蓄積するが、電子ビ
ーム照射時間が極短い場合には電気的にはほとんど中性
であるといえる。両者の領域の輝度が等しければ両領域
間での電荷の相互移動が無く電気的に中性であることか
ら、二次電子放出利得δ＝１であり、用いた加速電圧Ｖ
ａがＶ１である。Now, a method of determining the acceleration voltage V1 at which the secondary electron emission gain δ becomes 1 will be described with reference to FIG. First,
The sample is scanned with the electron beam at an arbitrary magnification for a certain period of time using an arbitrary acceleration voltage Va, and then switched to a low magnification,
The three states of secondary electron emission gains δ = 1,> 1, <1 are discriminated by the brightness of the high-magnification region scanned by the electron beam first compared with the brightness of the low-magnification region. Immediately after switching to a low magnification, the low magnification region receives electron beam irradiation and a slight amount of positive charges accumulate on the sample surface, but it is almost electrically neutral when the electron beam irradiation time is extremely short. Can be said. If the brightness of both regions is equal, there is no mutual movement of charges between the two regions and they are electrically neutral, so the secondary electron emission gain δ = 1 and the acceleration voltage V used.
a is V1.
【００１７】一方、高倍率ビーム走査領域の輝度が低倍
率領域の輝度に比べて黒い場合は、高倍率領域より電子
が流出していることになり、試料表面には正電荷が蓄積
されており、二次電子放出利得δ＞１と決定できる。他
方、高倍率ビーム走査領域の輝度が低倍率領域の輝度に
比べて白い場合は、高倍率領域に電子が流入しているこ
とになり、試料表面には負電荷が蓄積されており、二次
電子放出利得δ＜１と決定できる。On the other hand, when the brightness in the high-magnification beam scanning region is darker than that in the low-magnification region, electrons have flowed out from the high-magnification region, and positive charges are accumulated on the sample surface. , Secondary electron emission gain δ> 1. On the other hand, when the brightness of the high-magnification beam scanning area is white compared to the brightness of the low-magnification area, electrons have flowed into the high-magnification area, and negative charges are accumulated on the sample surface, causing a secondary charge. It can be determined that the electron emission gain δ <1.
【００１８】二次電子放出利得δ＞１の場合には、当初
の加速電圧ＶａにｎＶｂ（Ｖｂ：任意の加速電圧、ｎ：
繰り返し回数）を加えて印加し、二次電子放出利得がδ
＝１またはδ＜１になるまで繰り返し行う。二次電子放
出利得がδ＜１の場合には、加速電圧（Ｖａ＋ｎＶｂ）
−ｍＶｃ(Ｖｃ：任意の加速電圧，ｍ：繰り返し回数)を
印加して、二次電子放出利得δが１になるまで繰り返し
行う。When the secondary electron emission gain δ> 1, the initial acceleration voltage Va is nVb (Vb: arbitrary acceleration voltage, n:
The secondary electron emission gain is δ
Repeat until = 1 or δ <1. When the secondary electron emission gain is δ <1, the acceleration voltage (Va + nVb)
-MVc (Vc: arbitrary acceleration voltage, m: number of repetitions) is applied and repeated until the secondary electron emission gain δ becomes 1.
【００１９】本実施例によれば、二次電子放出利得δが
１となる加速電圧を自動的に設定して電子ビームを走査
することにより、どんな材質の試料表面でも電荷が蓄積
されることが無いためチャージアップを完全に防止で
き、像観察及びＸ線分析を行うべき微細コンタクトパタ
ーンの位置決めを容易に行うことができ、引き続いて高
倍率像観察やＸ線分析を行う際に試料上の特定パターン
の識別を容易に行うことができる。また、第一の実施例
と同様に、像観察後の試料表面には異物，金属薄膜等が
残存しないため、試料を後の半導体製造工程に戻しても
支障を来すことが無く、インライン評価が可能である。According to this embodiment, by automatically setting the accelerating voltage at which the secondary electron emission gain δ is 1 and scanning the electron beam, charges can be accumulated on the surface of the sample of any material. Since there is no charge-up, it is possible to completely prevent charge-up, and it is possible to easily position a fine contact pattern for image observation and X-ray analysis, and to specify on the sample when subsequently performing high-magnification image observation or X-ray analysis. The pattern can be easily identified. Further, as in the first embodiment, since no foreign matter, metal thin film, etc. remain on the sample surface after image observation, there is no problem even if the sample is returned to the subsequent semiconductor manufacturing process, and in-line evaluation is performed. Is possible.
【００２０】（実施例 ３）図４には加速電圧と二次電
子放出利得の関係を、図５にはタイムチャートをそれぞ
れ示す。(Embodiment 3) FIG. 4 shows the relationship between the acceleration voltage and the secondary electron emission gain, and FIG. 5 shows a time chart.
【００２１】本実施例は、表面材料がレジストの微細コ
ンタクトホールパターン内に電子ビームをポイント状に
細く集束して照射し、コンタクトホール底部の残留物を
Ｘ線分析する際に、二次電子放出利得がδ＜１の加速電
圧Ｖ２を用いてコンタクトホールパターン内にポイント
ビームをある一定時間照射しＸ線分析を行うことと、二
次電子放出利得がδ＞１の加速電圧Ｖ３に切り替えてＸ
線分析を行っているコンタクトホールの周囲に電子ビー
ムを短時間走査することを交互に複数回繰り返して行う
方法である。In this embodiment, when the surface material irradiates a fine contact hole pattern of a resist with an electron beam focused in a fine point-like manner and irradiating the residue at the bottom of the contact hole with an X-ray, secondary electron emission is performed. X-ray analysis is performed by irradiating a point beam in the contact hole pattern for a certain period of time using an acceleration voltage V2 having a gain δ <1, and switching to an acceleration voltage V3 having a secondary electron emission gain δ> 1 is performed.
This is a method in which scanning of an electron beam around a contact hole for which line analysis is performed for a short time is alternately repeated a plurality of times.
【００２２】従来のコンタクトホール底部残留物のＸ線
分析方法では、二次電子放出利得がδ＜１の加速電圧Ｖ
２でポイントビーム状に長時間照射するため、ホール底
部やホール周辺に蓄積した電荷量の大きな負電荷によ
り、電子ビームが曲げられてホール底部に到達しなくな
り、Ｘ線分析を長時間行うことができないという問題が
あった。According to the conventional X-ray analysis method for the residue at the bottom of the contact hole, the accelerating voltage V with the secondary electron emission gain δ <1 is obtained.
Since the point beam is irradiated for a long time at 2, the electron beam is bent and does not reach the bottom of the hole due to the negative charges with a large amount of charge accumulated in the hole bottom and the vicinity of the hole, and X-ray analysis can be performed for a long time. There was a problem that I could not.
【００２３】しかし、本実施例によれば、加速電圧Ｖ２
のポイントビーム照射によりホール底部やホール周辺に
負電荷が蓄積しても、加速電圧Ｖ３のビーム走査により
蓄積した負電荷を打ち消すことができるため電子ビーム
が曲げられることが無く、従ってＸ線分析を長時間行う
ことができ、高感度のＸ線分析が可能である。また、本
実施例においても、第一及び第二の実施例と同様に、像
観察後の試料表面には異物，金属薄膜等が残存しないた
め、試料を後の半導体製造工程に戻しても支障を来すこ
とが無く、インライン評価が可能である。However, according to this embodiment, the acceleration voltage V2
Even if negative charges are accumulated at the bottom of the hole or around the hole due to the point beam irradiation, the electron beam is not bent because the negative charges accumulated by the beam scanning of the acceleration voltage V3 can be canceled out, and therefore X-ray analysis can be performed. It can be performed for a long time, and highly sensitive X-ray analysis is possible. Also in this embodiment, as in the first and second embodiments, no foreign matter, metal thin film or the like remains on the surface of the sample after image observation, so that there is no problem even if the sample is returned to the subsequent semiconductor manufacturing process. In-line evaluation is possible without having to wait.
【００２４】（実施例 ４）本実施例を図６を用いて説
明する。本実施例では、同一構造の微細コンタクトホー
ル１１が複数個配列されている場合の微細コンタクトホ
ール１１内に電子ビームをポイント状に細く集束して照
射し、コンタクトホール底部の残留物をＸ線分析する際
において、まず、計測点１３を分析する。次に、ある一
定時間分析後に、計測点１４に電子ビームを自動的に移
動させて継続して分析を行う。一定時間経過後、計測点
１５、さらに計測点１６に計測点を移動して分析を継続
する。しかる後に、計測点１３′すなわち計測点１３に
戻り、継続して分析を行う方法である。(Embodiment 4) This embodiment will be described with reference to FIG. In this embodiment, when a plurality of fine contact holes 11 having the same structure are arranged, an electron beam is focused and irradiated in a fine point shape in the fine contact holes 11, and the residue at the bottom of the contact holes is analyzed by X-ray analysis. In doing so, first, the measurement point 13 is analyzed. Next, after the analysis for a certain period of time, the electron beam is automatically moved to the measurement point 14 to continue the analysis. After a lapse of a certain time, the measurement point is moved to the measurement point 15 and further to the measurement point 16 to continue the analysis. After that, it is a method of returning to the measurement point 13 ', that is, the measurement point 13 and continuing the analysis.
【００２５】従来方法の問題点として、同一の計測点を
長時間分析し続けるとホール底部やホール周辺に過大な
負電荷が蓄積し、電子ビームが曲げられてホール底部に
到達しなくなり、Ｘ線分析を長時間行うことができない
という問題が生じる。また、同一の計測点に長時間電子
ビームを照射し続けるとコンタミネーションの付着量が
増大し、分析感度の低下を招くという問題があった。As a problem of the conventional method, if the same measurement point is continuously analyzed for a long time, an excessive negative charge is accumulated at the bottom of the hole or around the hole, and the electron beam is bent and does not reach the bottom of the hole. The problem arises that the analysis cannot be performed for a long time. Further, if the same measurement point is continuously irradiated with the electron beam for a long time, the amount of contamination adhered increases, and there is a problem that the analysis sensitivity is lowered.
【００２６】しかし、本実施例によれば、ホール底部や
ホール周辺に過大な負電荷が蓄積する前に計測点を順次
移動していくため、電子ビームのコンタクトホール内へ
の侵入を妨げられることがなく、Ｘ線分析を実効的に長
時間行うことが可能となる。また、一箇所当りの計測時
間を少なくできるためコンタミネーションの付着量を少
なくすることができ、高感度のＸ線分析が可能である。
さらに、特定の計測点において、一度蓄積した負電荷が
時間経過に伴い電気的中性状態に戻った後に、再度、Ｘ
線分析を行うことにより、移動させながら分析を行う際
の分析領域を少なくすることができ、従って試料ステー
ジの移動精度の高い分析を行うことができる。さらに
は、本実施例でも、第一ないし第三の実施例と同様に、
分析後の試料表面には異物，金属薄膜等が残存しないた
め、試料を後の半導体製造工程に戻しても支障を来すこ
とが無く、インライン評価が可能である。However, according to the present embodiment, the measurement points are sequentially moved before excessive negative charges are accumulated at the bottom of the hole or around the hole, so that the electron beam can be prevented from entering the contact hole. Therefore, X-ray analysis can be effectively performed for a long time. Moreover, since the measurement time per location can be shortened, the amount of contamination attached can be reduced, and highly sensitive X-ray analysis is possible.
Further, at a specific measurement point, once the negative charges that have once accumulated return to an electrically neutral state with the passage of time, X
By performing the line analysis, it is possible to reduce the analysis region when performing the analysis while moving the sample, and thus it is possible to perform the analysis with high movement accuracy of the sample stage. Furthermore, also in this embodiment, as in the first to third embodiments,
Since no foreign matter, metal thin film, or the like remains on the surface of the sample after analysis, in-line evaluation is possible without causing any trouble even if the sample is returned to the subsequent semiconductor manufacturing process.
【００２７】[0027]
【発明の効果】本発明によれば、像観察あるいはＸ線分
析を行う際に試料表面に蓄積した電荷を、反対極性の電
荷が発生する異なる加速電圧に切り替えて電子ビームを
照射することにより、試料表面のチャージアップを防止
することができる。また、像観察あるいはＸ線分析後の
試料表面には異物，金属薄膜等が残存しないため、試料
を後の半導体製造工程に戻しても重金属汚染等の支障を
来すことが無く、インライン評価が可能である。According to the present invention, the charge accumulated on the surface of the sample during image observation or X-ray analysis is switched to a different accelerating voltage at which a charge of opposite polarity is generated, and the electron beam is irradiated. It is possible to prevent charge-up on the sample surface. Further, since no foreign matter, metal thin film, etc. remain on the sample surface after image observation or X-ray analysis, even if the sample is returned to the subsequent semiconductor manufacturing process, heavy metal contamination or the like does not occur, and in-line evaluation is possible. It is possible.
【図１】本発明の第一の実施例における加速電圧と二次
電子放出利得の関係を示す説明図。FIG. 1 is an explanatory diagram showing a relationship between an accelerating voltage and a secondary electron emission gain according to a first embodiment of the present invention.
【図２】本発明の第一の実施例における自動画像移動補
正機構を示すブロック図。FIG. 2 is a block diagram showing an automatic image movement correction mechanism in the first embodiment of the present invention.
【図３】本発明の第二の実施例における加速電圧Ｖ１の
決定手法を示すフローチャート。FIG. 3 is a flowchart showing a method of determining an acceleration voltage V1 according to a second embodiment of the present invention.
【図４】本発明の第三の実施例における加速電圧と二次
電子放出利得の関係を示す特性図。FIG. 4 is a characteristic diagram showing the relationship between the acceleration voltage and the secondary electron emission gain in the third embodiment of the present invention.
【図５】本発明の第三の実施例におけるタイムチャート
を示す図。FIG. 5 is a diagram showing a time chart in the third embodiment of the present invention.
【図６】本発明の第四の実施例における計測位置移動手
法を示す説明図。FIG. 6 is an explanatory diagram showing a measuring position moving method according to a fourth embodiment of the present invention.
【符号の説明】 δ…二次電子放出利得、Ｖ１…二次電子放出利得δが１
の加速電圧、１…電子銃、２…コンデンサレンズ、３…
偏向コイル、４…対物レンズ、５…電子ビーム、６…試
料、７…検出増幅部、８…画像表示部、９…画像処理
部、１０…画像移動補正部。[Explanation of Codes] δ ... Secondary electron emission gain, V1 ... Secondary electron emission gain δ is 1
Acceleration voltage, 1 ... electron gun, 2 ... condenser lens, 3 ...
Deflection coil, 4 objective lens, 5 electron beam, 6 sample, 7 detection amplification section, 8 image display section, 9 image processing section, 10 image movement correction section.
フロントページの続き (72)発明者 黒田 勝広 東京都国分寺市東恋ケ窪１丁目280番地 株式会社日立製作所中央研究所内 (72)発明者 戸所 秀男 茨城県勝田市市毛882番地 株式会社日立 製作所計測器事業部内Front page continuation (72) Inventor Katsuhiro Kuroda 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Hideo Todo, 882, Ige, Katsuta, Ibaraki Hitachi, Ltd. Department
Claims (10)
し、前記試料の表面から放出される二次電子又は反射電
子を検出増幅し、前記試料上の走査と同期して像観察用
画面表示部上で走査し輝度変調して像を表示する走査型
電子顕微鏡により像観察あるいは分析を行う場合におい
て、像観察あるいは分析を行うべくパターンの位置決め
を行う際の加速電圧と、像観察あるいは分析時の加速電
圧とが異なることを特徴とする走査型電子顕微鏡による
計測方法。1. A screen for observing an image in synchronization with scanning on the sample, in which an electron beam is focused finely to scan on the sample to detect and amplify secondary electrons or reflected electrons emitted from the surface of the sample. When performing image observation or analysis with a scanning electron microscope that scans on the display unit and displays the image with brightness modulation, the acceleration voltage and the image observation or analysis when positioning the pattern for image observation or analysis. A measuring method using a scanning electron microscope, which is characterized in that the acceleration voltage at the time is different.
料の表面を分析する際に、前記試料の表面がチャージア
ップしない加速電圧を用いてパターンの位置決めを行う
走査型電子顕微鏡による計測方法。2. The measuring method by a scanning electron microscope according to claim 1, wherein, when analyzing the surface of the non-conductive material sample, the pattern is positioned by using an accelerating voltage that does not charge up the surface of the sample. .
位置決め時の加速電圧は、前記試料の表面から放出され
る二次電子の放出利得が１以上となる加速電圧により行
う走査型電子顕微鏡による計測方法。3. The measurement by a scanning electron microscope according to claim 1, wherein the acceleration voltage at the time of pattern positioning is measured by an acceleration voltage at which the emission gain of secondary electrons emitted from the surface of the sample is 1 or more. Method.
行いながら分析を行う際の加速電圧は、螢光Ｘ線エネル
ギが励起可能な加速電圧である走査型電子顕微鏡による
計測方法。4. The measuring method by a scanning electron microscope according to claim 1, wherein the accelerating voltage used for analysis while observing an image is an accelerating voltage capable of exciting fluorescent X-ray energy.
行いながら分析を行う際の加速電圧は、０.５〜５.０ｋ
Ｖである走査型電子顕微鏡による計測方法。5. The accelerating voltage for analysis while observing an image according to claim 1, 2, or 3, is 0.5 to 5.0 k.
V is a scanning electron microscope measuring method.
行いながら分析を行う際の加速電圧は、対象とする材質
の特性Ｘ線エネルギの１〜１０倍である走査型電子顕微
鏡による計測方法。6. The scanning electron microscope according to claim 1, 2 or 3, wherein the accelerating voltage when performing analysis while observing an image is 1 to 10 times the characteristic X-ray energy of the target material. Method.
るいは分析工程と、像観察あるいは分析時に試料表面に
蓄積する電荷とは反対極性の電荷が発生する加速電圧に
切り替えて短時間電子ビーム走査を行って表面蓄積電荷
を打ち消す工程とを繰り返して行う走査型電子顕微鏡に
よる分析方法。7. The electron beam for a short period of time according to claim 1, 2 or 3, wherein the image observing or analyzing step is switched to an accelerating voltage at which an electric charge having a polarity opposite to the electric charge accumulated on the sample surface during image observing or analyzing is generated. An analysis method using a scanning electron microscope, which comprises repeating a step of performing scanning to cancel surface accumulated charges.
造が複数存在する試料を計測する場合に、計測途中で計
測点を順次変えて、計測中に蓄積した表面電荷が放出さ
れて電気的に中性状態になった位置に再び戻って計測を
継続する走査型電子顕微鏡による計測方法。8. When measuring a sample having a plurality of similar structures according to claim 1, 2, or 3, the measurement points are sequentially changed during the measurement, and the surface charges accumulated during the measurement are discharged to cause an electrical change. Measurement method using a scanning electron microscope that returns to the position where it became a neutral state again and continues measurement.
速電圧により高倍率で試料上に電子ビームを走査した後
に低倍率で像観察を行う操作を複数回繰り返し、高倍率
領域と低倍率領域の輝度が等しくなる加速電圧を自動的
に決定する走査型電子顕微鏡による像観察方法。9. The method according to claim 1, 2 or 3, wherein an operation of observing an image at a low magnification after scanning the sample with an electron beam at a high magnification by various acceleration voltages is repeated a plurality of times to obtain a high magnification region and a low magnification. An image observation method using a scanning electron microscope that automatically determines an accelerating voltage at which the brightness of regions becomes equal.
て、二次電子又は反射電子を検出し増幅する検出増幅部
より画像信号を受けて画像位置の記憶並びに画像ずれ量
計算を行い、画像処理部からの画像ずれ量補正信号を受
けて画像の自動視野調整並びに自動焦点補正を行い、加
速電圧の変化に伴う画像移動及び像焦点変動を自動的に
補正する走査型電子顕微鏡計測方法。10. The method according to claim 1, 2, 3, 7 or 9, wherein an image signal is received from a detection / amplification unit which detects and amplifies secondary electrons or reflected electrons, and the image position is stored and the image shift amount is calculated A scanning electron microscope measuring method, which receives an image shift amount correction signal from an image processing unit, performs automatic visual field adjustment and automatic focus correction of an image, and automatically corrects image movement and image focus variation due to a change in acceleration voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15012893A JPH0714537A (en) | 1993-06-22 | 1993-06-22 | Measuring method by scanning electron microscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15012893A JPH0714537A (en) | 1993-06-22 | 1993-06-22 | Measuring method by scanning electron microscope |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0714537A true JPH0714537A (en) | 1995-01-17 |
Family
ID=15490099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15012893A Pending JPH0714537A (en) | 1993-06-22 | 1993-06-22 | Measuring method by scanning electron microscope |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0714537A (en) |
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