JP3517596B2 - Scanning electron microscope - Google Patents
Scanning electron microscopeInfo
- Publication number
- JP3517596B2 JP3517596B2 JP35622498A JP35622498A JP3517596B2 JP 3517596 B2 JP3517596 B2 JP 3517596B2 JP 35622498 A JP35622498 A JP 35622498A JP 35622498 A JP35622498 A JP 35622498A JP 3517596 B2 JP3517596 B2 JP 3517596B2
- Authority
- JP
- Japan
- Prior art keywords
- objective lens
- inner diameter
- sample
- magnetic field
- electron microscope
- 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.)
- Expired - Fee Related
Links
- 238000010894 electron beam technology Methods 0.000 claims description 28
- 150000001875 compounds Chemical class 0.000 claims description 12
- 238000001514 detection method Methods 0.000 description 26
- 230000004075 alteration Effects 0.000 description 6
- 230000001133 acceleration Effects 0.000 description 4
- 230000005684 electric field Effects 0.000 description 3
- 239000002131 composite material Substances 0.000 description 2
- 238000005094 computer simulation Methods 0.000 description 2
- 230000001965 increasing effect Effects 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、試料上で電子ビー
ムを２次元的に走査し、試料からの２次電子を効率良く
検出して試料の走査像を得るようにした走査電子顕微鏡
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning electron microscope which two-dimensionally scans an electron beam on a sample and efficiently detects secondary electrons from the sample to obtain a scan image of the sample.
【０００２】[0002]
【従来の技術】走査電子顕微鏡では、電子銃から発生し
加速された電子ビームをコンデンサレンズと対物レンズ
によって集束し、試料上に照射すると共に、試料上で電
子ビームを２次元的に走査し、試料から発生した２次電
子や反射電子を検出し、検出信号を陰極線管に供給して
試料の走査像を得るようにしている。2. Description of the Related Art In a scanning electron microscope, an electron beam generated from an electron gun and accelerated is focused by a condenser lens and an objective lens to irradiate a sample, and the electron beam is two-dimensionally scanned on the sample. Secondary electrons or backscattered electrons generated from the sample are detected and a detection signal is supplied to the cathode ray tube to obtain a scan image of the sample.
【０００３】このような走査電子顕微鏡において、試料
に収差の小さな電子ビームを照射して高い分解能の像を
観察すること、そして、試料から発生した２次電子を効
率良く２次電子検出器に導くことは重要であり、そのた
めの改良が種々行われている。In such a scanning electron microscope, a sample is irradiated with an electron beam having a small aberration to observe an image with high resolution, and secondary electrons generated from the sample are efficiently guided to a secondary electron detector. This is important, and various improvements have been made for that purpose.
【０００４】特開平６−１８８２９４号に記載された先
願の発明においては、試料の上に第１の磁界型対物レン
ズを配置し、更にその磁界型対物レンズの形成する磁場
内に複数の電極より成る静電型対物レンズを配置してい
る。このように磁界型対物レンズと静電型対物レンズの
形成する磁場と電場によってビームを集束することによ
り、低い加速電圧の一次電子ビームであってもを小さな
収差係数とすることができる。In the invention of the prior application described in Japanese Patent Laid-Open No. 6-188294, a first magnetic field type objective lens is arranged on a sample, and a plurality of electrodes are arranged in the magnetic field formed by the magnetic field type objective lens. And an electrostatic objective lens composed of Thus, by focusing the beam by the magnetic field and the electric field formed by the magnetic objective lens and the electrostatic objective lens, even a primary electron beam having a low acceleration voltage can have a small aberration coefficient.
【０００５】更にこの先願の発明においては、試料の下
に磁界型電子レンズを配置し、一次電子ビームの集束作
用を高めると共に、試料から発生した２次電子を光軸上
に集束させ、多くの２次電子を対物レンズの上部に設け
た２次電子検出器に導くように構成している。Further, in the invention of this prior application, a magnetic field type electron lens is arranged under the sample to enhance the focusing action of the primary electron beam, and the secondary electrons generated from the sample are focused on the optical axis, so that many The secondary electrons are guided to a secondary electron detector provided above the objective lens.
【０００６】[0006]
【発明が解決しようとする課題】上記した先願の発明に
おいては、一次電子ビームの収差係数を小さくできると
共に２次電子の検出効率を高めることが可能ではある
が、試料の上部に磁界型電子レンズと静電型電子レンズ
の組み合わせを配置し、試料の下部に更に磁界型電子レ
ンズを配置する複雑な構成となっており、装置が高価と
なる欠点を有している。In the invention of the above-mentioned prior application, although the aberration coefficient of the primary electron beam can be reduced and the detection efficiency of the secondary electrons can be improved, the magnetic field type electron is provided above the sample. The combination of the lens and the electrostatic type electron lens is arranged, and the magnetic field type electron lens is further arranged below the sample, which has a complicated structure, and has a drawback that the apparatus becomes expensive.
【０００７】本発明は、このような点に鑑みてなされた
もので、その目的は、簡単な構成で２次電子の検出効率
を高めることができる走査電子顕微鏡を実現するにあ
る。The present invention has been made in view of the above points, and an object thereof is to realize a scanning electron microscope capable of enhancing the detection efficiency of secondary electrons with a simple structure.
【０００８】[0008]
【課題を解決するための手段】第１の発明に基づく走査
電子顕微鏡は、電子銃からの電子ビームを対物レンズに
よって試料上に細く集束すると共に、試料上で電子ビー
ムを２次元的に走査し、この走査に基づいて試料から得
られた信号に基づいて試料像を陰極線管上に表示するよ
うにした走査電子顕微鏡において、対物レンズを磁界型
対物レンズと磁界型対物レンズの形成する磁場内に配置
された静電型対物レンズとにより構成された複合レンズ
とし、複合対物レンズの上部に２次電子検出器を配置
し、磁界型対物レンズの下部磁極内径を上部磁極内径よ
り大きくすると共に、静電型対物レンズを接地電位の上
部電極と負電位の下部電極とより構成し、この上部電極
の内径を下部電極の内径より大きくして試料からの２次
電子の検出効率を向上させる。According to a first aspect of the present invention, a scanning electron microscope finely focuses an electron beam from an electron gun onto a sample by an objective lens and scans the sample two-dimensionally with the electron beam. , In a scanning electron microscope that displays a sample image on a cathode ray tube based on a signal obtained from a sample based on this scanning, an objective lens is placed in a magnetic field type objective lens and a magnetic field formed by the magnetic field type objective lens. A composite lens composed of the electrostatic objective lens arranged and a secondary electron detector is arranged above the composite objective lens to make the inner diameter of the lower magnetic pole of the magnetic objective lens larger than the inner diameter of the upper magnetic pole. The electric objective lens is composed of an upper electrode of ground potential and a lower electrode of negative potential, and the inner diameter of this upper electrode is made larger than the inner diameter of the lower electrode to improve the detection efficiency of secondary electrons from the sample. Make.
【０００９】第２の発明に基づく走査電子顕微鏡は、第
１の発明において、磁界型対物レンズの下部磁極内径と
上部磁極内径との比を１．２〜２．０の範囲としたこと
を特徴としている。A scanning electron microscope based on a second invention is the scanning electron microscope according to the first invention, wherein the ratio of the inner diameter of the lower magnetic pole to the inner diameter of the upper magnetic pole of the magnetic field type objective lens is in the range of 1.2 to 2.0. I am trying.
【００１０】第３の発明に基づく走査電子顕微鏡は、第
１の発明において、静電型対物レンズの上部電極内径と
下部電極内径との比を３〜１２の範囲としたことを特徴
としている。The scanning electron microscope based on the third invention is characterized in that, in the first invention, the ratio of the inner diameter of the upper electrode to the inner diameter of the lower electrode of the electrostatic objective lens is set in the range of 3 to 12.
【００１１】第４の発明に基づく走査電子顕微鏡は、第
１の発明において、磁界型対物レンズの下部磁極内径と
上部磁極内径との比を１．２〜２．０の範囲とし、静電
型対物レンズの上部電極内径と下部電極内径との比を３
〜１２の範囲としたことを特徴としている。A scanning electron microscope based on a fourth invention is the electrostatic electron microscope according to the first invention, wherein the ratio of the inner diameter of the lower magnetic pole to the inner diameter of the upper magnetic pole of the magnetic field type objective lens is in the range of 1.2 to 2.0. The ratio between the inner diameter of the upper electrode and the inner diameter of the lower electrode of the objective lens is 3
It is characterized in that it is set in the range of -12.
【００１２】[0012]
【発明の実施の形態】以下、図面を参照して本発明の実
施の形態を詳細に説明する。図１は本発明に基づく走査
電子顕微鏡の対物レンズ部分を示しており、対物レンズ
１は磁界型対物レンズ２と静電型対物レンズ３との複合
対物レンズとなっている。磁界型対物レンズ２は上部磁
極４と下部磁極５と励磁コイル６とより構成されてお
り、励磁コイル６には図示していない励磁電源より励磁
電流が供給される。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an objective lens portion of a scanning electron microscope according to the present invention. The objective lens 1 is a compound objective lens of a magnetic field type objective lens 2 and an electrostatic type objective lens 3. The magnetic field type objective lens 2 is composed of an upper magnetic pole 4, a lower magnetic pole 5, and an exciting coil 6, and an exciting current is supplied to the exciting coil 6 from an exciting power source (not shown).
【００１３】静電型対物レンズ３は、上部電極７と下部
電極８とより構成されており、上部電極７は接地電位
に、下部電極８には電源９より負電位が印加されるよう
に構成されている。複合対物レンズ１の下部には、試料
１０が配置されており、試料１０には電源９から負電位
が印加される。The electrostatic objective lens 3 is composed of an upper electrode 7 and a lower electrode 8. The upper electrode 7 is applied with a ground potential, and the lower electrode 8 is applied with a negative potential from a power source 9. Has been done. A sample 10 is arranged below the compound objective lens 1, and a negative potential is applied to the sample 10 from a power source 9.
【００１４】複合対物レンズ１の上部には、ドーナツ状
の２次電子検出器１１が配置されており、検出器１１の
開口部１２を通って一次電子ビームＥＢが照射される。
このような構成の動作を次に説明する。A donut-shaped secondary electron detector 11 is arranged above the compound objective lens 1, and the primary electron beam EB is irradiated through the opening 12 of the detector 11.
The operation of such a configuration will be described below.
【００１５】図示していない電子銃１から発生し加速さ
れた一次電子ビームは、コンデンサレンズ（図示せず）
と複合対物レンズ１とによって試料１０上に細く集束さ
れる。この際、一次電子ビームＥＢは、複合対物レンズ
１の磁界型対物レンズ２と静電型対物レンズ３とによっ
て集束され、収差の小さな電子ビームが試料１０に照射
される。The primary electron beam generated from the electron gun 1 (not shown) and accelerated is a condenser lens (not shown).
And the compound objective lens 1 to finely focus on the sample 10. At this time, the primary electron beam EB is focused by the magnetic field type objective lens 2 of the compound objective lens 1 and the electrostatic type objective lens 3, and the electron beam with small aberration is irradiated on the sample 10.
【００１６】ここで、静電型対物レンズ３の上部電極７
は接地電位とされ、下部電極８と試料１０には電源９か
ら負電位が印加されている。例えば、一次電子ビームの
加速電圧が１０ｋＶの場合、下部電極８と試料１０には
それぞれ−９ｋＶが印加される。この結果、上部電極７
と下部電極８との間には一次電子ビームＥＢに対して減
速電界が形成され、試料１０には結果として加速電圧１
ｋＶの一次電子ビームが照射される。Here, the upper electrode 7 of the electrostatic objective lens 3
Is a ground potential, and a negative potential is applied to the lower electrode 8 and the sample 10 from a power source 9. For example, when the acceleration voltage of the primary electron beam is 10 kV, −9 kV is applied to each of the lower electrode 8 and the sample 10. As a result, the upper electrode 7
A deceleration electric field is formed between the lower electrode 8 and the lower electrode 8 with respect to the primary electron beam EB.
The primary electron beam of kV is irradiated.
【００１７】したがって、対物レンズ１において一次電
子ビームは高い加速電圧で集束作用を受けることから、
一次電子ビームを収差が小さい状態で細く集束させるこ
とが可能となると共に、試料１０には低い加速電圧で一
次電子ビームが照射されることから、試料１０が半導体
や絶縁物試料の場合には、試料の帯電を著しく少なくす
ることができる。もちろん、試料に照射される一次電子
ビームの加速電圧が低くされていることから、試料の一
次電子ビームによるダメージも小さくすることができ
る。Therefore, since the primary electron beam in the objective lens 1 is focused by a high acceleration voltage,
Since it is possible to focus the primary electron beam finely with a small aberration and the sample 10 is irradiated with the primary electron beam at a low acceleration voltage, when the sample 10 is a semiconductor or an insulator sample, The charge on the sample can be significantly reduced. Of course, since the accelerating voltage of the primary electron beam with which the sample is irradiated is lowered, the damage due to the primary electron beam of the sample can be reduced.
【００１８】試料１０に照射される一次電子ビームＥＢ
は図示していない偏向器によって２次元的に走査され
る。試料１０への一次電子ビームの照射によって発生し
た２次電子１３は、上部電極７と下部電極８との間の電
界によって加速され、磁界型対物レンズ２と静電型対物
レンズ３のレンズ作用により集束作用を受けて光軸方向
に集められ、対物レンズ１の中心部を通って上方に導か
れる。The primary electron beam EB irradiated on the sample 10.
Are two-dimensionally scanned by a deflector (not shown). Secondary electrons 13 generated by irradiating the sample 10 with the primary electron beam are accelerated by the electric field between the upper electrode 7 and the lower electrode 8, and are caused by the lens action of the magnetic field type objective lens 2 and the electrostatic type objective lens 3. It is focused in the direction of the optical axis by the focusing action, and guided upward through the center of the objective lens 1.
【００１９】対物レンズ１の上部に取り出された２次電
子１３は、ドーナツ状の２次電子検出器１１によって検
出される。検出器１１の検出信号は、図示していない陰
極線管に供給されることから、陰極線管上には走査２次
電子像が表示される。The secondary electrons 13 extracted above the objective lens 1 are detected by a donut-shaped secondary electron detector 11. Since the detection signal of the detector 11 is supplied to a cathode ray tube (not shown), a scanning secondary electron image is displayed on the cathode ray tube.
【００２０】上記したように、図１の構成の複合対物レ
ンズ１では、一次電子ビームＥＢを小さな収差で細く集
束することができると共に、試料１０からの２次電子を
効率良く集めて２次電子検出器１１に導くことができ
る。As described above, in the compound objective lens 1 having the structure shown in FIG. 1, the primary electron beam EB can be finely focused with a small aberration, and the secondary electrons from the sample 10 can be efficiently collected to obtain the secondary electrons. It can be led to the detector 11.
【００２１】ところで、本発明者は、複合対物レンズ１
を構成する磁界型対物レンズ２、静電型対物レンズ３の
形状について種々検討を加えたところ、磁界型対物レン
ズ２を構成する上部磁極４の内径と下部磁極５の内径と
の比、静電型対物レンズ３を構成する上部電極７の内径
と下部電極８の内径との比が、２次電子検出器１１にお
ける２次電子検出効率に大きな影響を与えることを見出
だした。By the way, the present inventor has found that the compound objective lens 1
Various investigations were made on the shapes of the magnetic field type objective lens 2 and the electrostatic type objective lens 3 that make up the magnetic field type objective lens 2. As a result, the ratio of the inner diameter of the upper magnetic pole 4 and the inner diameter of the lower magnetic pole 5 forming the magnetic field type objective lens 2 It has been found that the ratio of the inner diameter of the upper electrode 7 and the inner diameter of the lower electrode 8 forming the objective lens 3 has a great influence on the secondary electron detection efficiency of the secondary electron detector 11.
【００２２】すなわち、複合対物レンズ１の上部に２次
電子検出器１１を配置し、磁界型対物レンズ２の下部磁
極５の内径を上部磁極４の内径より大きくすると共に、
接地電位の上部電極７と負電位の下部電極８とより構成
される静電型対物レンズ３の上部電極７の内径を下部電
極８の内径より大きくすることにより、２次電子の検出
効率を高めることができることを見出だした。That is, the secondary electron detector 11 is arranged above the compound objective lens 1 to make the inner diameter of the lower magnetic pole 5 of the magnetic field type objective lens 2 larger than the inner diameter of the upper magnetic pole 4.
By increasing the inner diameter of the upper electrode 7 of the electrostatic objective lens 3 composed of the upper electrode 7 of ground potential and the lower electrode 8 of negative potential to be larger than the inner diameter of the lower electrode 8, the detection efficiency of secondary electrons is improved. I found that I could do it.
【００２３】ここで、図２に示すように、磁界型対物レ
ンズ２の上部磁極４の内径をＤＭ１、下部磁極５の内径
をＤＭ２、静電型対物レンズ３の上部電極７の内径をＤ
Ｅ１、下部電極８の内径をＤＥ２とし、コンピュータシ
ミュレーションにより各内径の値を変化させて２次電子
検出器１１における２次電子の検出効率を求めた。ＤＥ
１／ＤＥ２の値が３〜１２における結果の一例を図３の
表に示す。Here, as shown in FIG. 2, the inner diameter of the upper magnetic pole 4 of the magnetic field type objective lens 2 is DM1, the inner diameter of the lower magnetic pole 5 is DM2, and the inner diameter of the upper electrode 7 of the electrostatic objective lens 3 is D.
E1 and the inner diameter of the lower electrode 8 were set to DE2, the value of each inner diameter was changed by computer simulation, and the detection efficiency of the secondary electron in the secondary electron detector 11 was calculated | required. DE
An example of the results when the value of 1 / DE2 is 3 to 12 is shown in the table of FIG.
【００２４】図３の表において、ａのケースではＤＥ１
／ＤＥ２の値が１．０でＤＭ２／ＤＭ１の値が２．１の
時、２次電子の検出効率は４６％であった。ｂのケース
では、ＤＥ１／ＤＥ２の値が１．０でＤＭ２／ＤＭ１の
値が３．０の時、２次電子の検出効率は４８％であっ
た。ｃのケースではＤＥ１／ＤＥ２の値が２．４でＤＭ
２／ＤＭ１の値が２．１の時、２次電子の検出効率は５
０％であった。In the table of FIG. 3, in the case of a, DE1
When the value of / DE2 was 1.0 and the value of DM2 / DM1 was 2.1, the detection efficiency of secondary electrons was 46%. In the case of b, when the value of DE1 / DE2 was 1.0 and the value of DM2 / DM1 was 3.0, the detection efficiency of secondary electrons was 48%. In the case of c, the value of DE1 / DE2 is 2.4 and DM
When the value of 2 / DM1 is 2.1, the detection efficiency of secondary electrons is 5
It was 0%.
【００２５】また、ｄのケースではＤＥ１／ＤＥ２の値
が３．０でＤＭ２／ＤＭ１の値が２．１の時、２次電子
の検出効率は６４％であった。ｅのケースではＤＥ１／
ＤＥ２の値が４．０でＤＭ２／ＤＭ１の値が２．１の
時、２次電子の検出効率は６５％であった。ｆのケース
ではＤＥ１／ＤＥ２の値が１．２５でＤＭ２／ＤＭ１の
値が２．１の時、２次電子の検出効率は６６％であっ
た。In the case of d, when the DE1 / DE2 value was 3.0 and the DM2 / DM1 value was 2.1, the detection efficiency of secondary electrons was 64%. In case of e, DE1 /
When the value of DE2 was 4.0 and the value of DM2 / DM1 was 2.1, the detection efficiency of secondary electrons was 65%. In the case of f, when the value of DE1 / DE2 was 1.25 and the value of DM2 / DM1 was 2.1, the detection efficiency of secondary electrons was 66%.
【００２６】更に、ｇのケースではＤＥ１／ＤＥ２の値
が４．０でＤＭ２／ＤＭ１の値が１．５の時、２次電子
の検出効率は７２％であった。ｈのケースではＤＥ１／
ＤＥ２の値が４．０でＤＭ２／ＤＭ１の値が１．３の
時、２次電子の検出効率は７４％であった。ｉのケース
ではＤＥ１／ＤＥ２の値が４．０でＤＭ２／ＤＭ１の値
が１．４４の時、２次電子の検出効率は７６％であっ
た。Further, in the case of g, the detection efficiency of secondary electrons was 72% when the value of DE1 / DE2 was 4.0 and the value of DM2 / DM1 was 1.5. In case of h, DE1 /
When the value of DE2 was 4.0 and the value of DM2 / DM1 was 1.3, the detection efficiency of secondary electrons was 74%. In the case of i, when the value of DE1 / DE2 was 4.0 and the value of DM2 / DM1 was 1.44, the detection efficiency of secondary electrons was 76%.
【００２７】また更に、ｊのケースではＤＥ１／ＤＥ２
の値が６．０でＤＭ２／ＤＭ１の値が１．４４の時、２
次電子の検出効率は７１％であった。ｋのケースではＤ
Ｅ１／ＤＥ２の値が１０．８でＤＭ２／ＤＭ１の値が
１．２７の時、２次電子の検出効率は７１％であった。Furthermore, in the case of j, DE1 / DE2
When the value of is 6.0 and the value of DM2 / DM1 is 1.44, 2
The detection efficiency of secondary electrons was 71%. D in case of k
When the value of E1 / DE2 was 10.8 and the value of DM2 / DM1 was 1.27, the detection efficiency of secondary electrons was 71%.
【００２８】図４は縦軸をＤＥ１／ＤＥ２、横軸をＤＭ
２／ＤＭ１とし、上記した各シミュレーションの結果を
プロットしたものである。この図３、図４から下部磁極
の内径は上部磁極の内径より大きいこと、特に、下部磁
極の内径ＤＭ２は、上部磁極の内径ＤＭ１の１．２倍程
度乃至１．５倍程度であれば、顕著に２次電子の検出効
率が向上することが導かれる。なお、ＤＭ２／ＤＭ１の
値があまり大きくなってもそれ程の効果が得られないこ
とも判明した。In FIG. 4, the vertical axis is DE1 / DE2 and the horizontal axis is DM.
2 / DM1, and the results of the above-described simulations are plotted. 3 and 4, the inner diameter of the lower magnetic pole is larger than the inner diameter of the upper magnetic pole, and in particular, the inner diameter DM2 of the lower magnetic pole is about 1.2 to 1.5 times the inner diameter DM1 of the upper magnetic pole. It can be seen that the secondary electron detection efficiency is significantly improved. It was also found that such an effect could not be obtained even if the value of DM2 / DM1 was too large.
【００２９】また、静電型対物レンズ３の上部電極７の
内径ＤＥ１は、下部電極８の内径ＤＥ２より大きいこ
と、特に、その比が３倍以上であれば、顕著に２次電子
の検出効率が向上することが導かれる。Further, the inner diameter DE1 of the upper electrode 7 of the electrostatic objective lens 3 is larger than the inner diameter DE2 of the lower electrode 8, and particularly when the ratio is 3 times or more, the detection efficiency of secondary electrons is remarkably increased. Will be improved.
【００３０】[0030]
【発明の効果】第１の発明に基づく走査電子顕微鏡は、
電子銃からの電子ビームを対物レンズによって試料上に
細く集束すると共に、試料上で電子ビームを２次元的に
走査し、この走査に基づいて試料から得られた信号に基
づいて試料像を陰極線管上に表示するようにした走査電
子顕微鏡において、対物レンズを磁界型対物レンズと磁
界型対物レンズの形成する磁場内に配置された静電型対
物レンズとにより構成された複合レンズとし、複合対物
レンズの上部に２次電子検出器を配置し、磁界型対物レ
ンズの下部磁極内径を上部磁極内径より大きくすると共
に、静電型対物レンズを接地電位の上部電極と負電位の
下部電極とより構成し、この上部電極の内径を下部電極
の内径より大きくした。この結果、簡単な構成で試料か
らの２次電子の検出効率を向上させることができる。The scanning electron microscope according to the first invention is
The electron beam from the electron gun is finely focused on the sample by the objective lens, the electron beam is two-dimensionally scanned on the sample, and the sample image is formed on the basis of the signal obtained from the sample based on this scanning. In the scanning electron microscope as shown above, the objective lens is a compound lens composed of a magnetic field type objective lens and an electrostatic type objective lens arranged in a magnetic field formed by the magnetic field type objective lens. A secondary electron detector is arranged above the magnetic field type objective lens to make the inner diameter of the lower magnetic pole of the magnetic field type objective lens larger than the inner diameter of the upper magnetic pole, and the electrostatic type objective lens is composed of an upper electrode of ground potential and a lower electrode of negative potential. The inner diameter of the upper electrode was made larger than that of the lower electrode. As a result, the detection efficiency of the secondary electrons from the sample can be improved with a simple structure.
【００３１】第２の発明に基づく走査電子顕微鏡は、第
１の発明において、磁界型対物レンズの下部磁極内径と
上部磁極内径との比を１．２〜２．０の範囲としたこと
を特徴としており、試料からの２次電子の検出効率を向
上させることができる。The scanning electron microscope based on the second invention is the scanning electron microscope according to the first invention, wherein the ratio of the inner diameter of the lower magnetic pole to the inner diameter of the upper magnetic pole of the magnetic field type objective lens is in the range of 1.2 to 2.0. Therefore, the detection efficiency of the secondary electrons from the sample can be improved.
【００３２】第３の発明に基づく走査電子顕微鏡は、第
１の発明において、静電型対物レンズの上部電極内径と
下部電極内径との比を３〜１２の範囲としたことを特徴
としており、試料からの２次電子の検出効率を向上させ
ることができる。The scanning electron microscope according to the third invention is characterized in that, in the first invention, the ratio of the inner diameter of the upper electrode to the inner diameter of the lower electrode of the electrostatic objective lens is set in the range of 3 to 12. The detection efficiency of secondary electrons from the sample can be improved.
【００３３】第４の発明に基づく走査電子顕微鏡は、第
１の発明において、磁界型対物レンズの下部磁極内径と
上部磁極内径との比を１．２〜２．０の範囲とし、静電
型対物レンズの上部電極内径と下部電極内径との比を３
〜１２の範囲としたことを特徴としており、試料からの
２次電子の検出効率を向上させることができる。The scanning electron microscope based on the fourth invention is the electrostatic electron microscope according to the first invention, wherein the ratio of the inner diameter of the lower magnetic pole to the inner diameter of the upper magnetic pole of the magnetic field type objective lens is in the range of 1.2 to 2.0. The ratio between the inner diameter of the upper electrode and the inner diameter of the lower electrode of the objective lens is 3
It is characterized in that it is set in the range of to 12, so that the detection efficiency of secondary electrons from the sample can be improved.
【図１】本発明に基づく走査電子顕微鏡の要部を示す図
である。FIG. 1 is a diagram showing a main part of a scanning electron microscope according to the present invention.
【図２】磁界型対物レンズと静電型対物レンズ部分の拡
大図である。FIG. 2 is an enlarged view of a magnetic field type objective lens and an electrostatic type objective lens portion.
【図３】２次電子の検出効率のコンピュータシミュレー
ション結果を示す表である。FIG. 3 is a table showing computer simulation results of secondary electron detection efficiency.
【図４】図３のシミュレーション結果を縦軸をＤＥ１／
ＤＥ２、横軸をＤＭ２／ＤＭ１としたグラフ上にプロッ
トした結果を示す図である。FIG. 4 shows the simulation result of FIG.
It is a figure which shows the result plotted on the graph which made DE2 and a horizontal axis DM2 / DM1.
１ 複合対物レンズ ２ 磁界型対物レンズ ３ 静電型対物レンズ ４ 上部磁極 ５ 下部磁極 ６ 励磁コイル ７ 上部電極 ８ 下部電極 ９ 電源 １０ 試料 １１ ２次電子検出器 1 Compound objective lens 2 Magnetic field type objective lens 3 Electrostatic type objective lens 4 upper magnetic pole 5 lower magnetic pole 6 Excitation coil 7 Upper electrode 8 Lower electrode 9 power supplies 10 samples 11 Secondary electron detector
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01J 37/10 - 37/145 H01J 37/244 H01J 37/28 ─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. 7 , DB name) H01J 37/10-37/145 H01J 37/244 H01J 37/28
Claims (4)
よって試料上に細く集束すると共に、試料上で電子ビー
ムを２次元的に走査し、この走査に基づいて試料から得
られた信号に基づいて試料像を陰極線管上に表示するよ
うにした走査電子顕微鏡において、対物レンズを磁界型
対物レンズと磁界型対物レンズの形成する磁場内に配置
された静電型対物レンズとにより構成された複合レンズ
とし、複合対物レンズの上部に２次電子検出器を配置
し、磁界型対物レンズの下部磁極内径を上部磁極内径よ
り大きくすると共に、静電型対物レンズを接地電位の上
部電極と負電位の下部電極とより構成し、この上部電極
の内径を下部電極の内径より大きくしたことを特徴とす
る走査電子顕微鏡。1. An electron beam from an electron gun is finely focused on a sample by an objective lens, the electron beam is two-dimensionally scanned on the sample, and based on a signal obtained from the sample based on this scanning. In a scanning electron microscope configured to display a sample image on a cathode ray tube, a compound lens having an objective lens composed of a magnetic field type objective lens and an electrostatic type objective lens arranged in a magnetic field formed by the magnetic field type objective lens. The secondary electron detector is arranged above the compound objective lens, the inner diameter of the lower magnetic pole of the magnetic field type objective lens is made larger than the inner diameter of the upper magnetic pole, and the electrostatic objective lens is set to the upper electrode of ground potential and the lower portion of negative potential. A scanning electron microscope comprising an electrode and an inner diameter of the upper electrode larger than that of the lower electrode.
磁極内径との比が１．２〜２．０の範囲であることを特
徴とする請求項１記載の走査電子顕微鏡。2. The scanning electron microscope according to claim 1, wherein the ratio of the inner diameter of the lower magnetic pole to the inner diameter of the upper magnetic pole of the magnetic field type objective lens is in the range of 1.2 to 2.0.
電極内径との比が３〜１２の範囲であることを特徴とす
る請求項１記載の走査電子顕微鏡。3. The scanning electron microscope according to claim 1, wherein the ratio of the inner diameter of the upper electrode to the inner diameter of the lower electrode of the electrostatic objective lens is in the range of 3 to 12.
磁極内径との比が１．２〜２．０の範囲であり、静電型
対物レンズの上部電極内径と下部電極内径との比が３〜
１２の範囲であることを特徴とする請求項１記載の走査
電子顕微鏡。4. The ratio of the lower magnetic pole inner diameter to the upper magnetic pole inner diameter of the magnetic field type objective lens is in the range of 1.2 to 2.0, and the ratio of the upper electrode inner diameter to the lower electrode inner diameter of the electrostatic type objective lens is 3-
The scanning electron microscope according to claim 1, wherein the scanning electron microscope has a range of 12.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35622498A JP3517596B2 (en) | 1998-12-15 | 1998-12-15 | Scanning electron microscope |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP35622498A JP3517596B2 (en) | 1998-12-15 | 1998-12-15 | Scanning electron microscope |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000182558A JP2000182558A (en) | 2000-06-30 |
| JP3517596B2 true JP3517596B2 (en) | 2004-04-12 |
Family
ID=18447969
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP35622498A Expired - Fee Related JP3517596B2 (en) | 1998-12-15 | 1998-12-15 | Scanning electron microscope |
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| Country | Link |
|---|---|
| JP (1) | JP3517596B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1956631B1 (en) | 2002-12-17 | 2012-06-20 | ICT Integrated Circuit Testing Gesellschaft für Halbleiterprüftechnik mbH | Lens system for a plurality of charged particle beams |
| DE102007010873B4 (en) * | 2007-03-06 | 2009-07-30 | Carl Zeiss Nts Gmbh | objective lens |
| JP5227643B2 (en) | 2008-04-14 | 2013-07-03 | 株式会社日立ハイテクノロジーズ | An electron beam application device that enables observation with high resolution and high contrast |
| US9159528B2 (en) | 2013-06-07 | 2015-10-13 | Samsung Electronics Co., Ltd. | Electron beam apparatus |
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1998
- 1998-12-15 JP JP35622498A patent/JP3517596B2/en not_active Expired - Fee Related
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|---|---|
| JP2000182558A (en) | 2000-06-30 |
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