JPH0961142A - Method and apparatus for measurement of film thickness - Google Patents
Method and apparatus for measurement of film thicknessInfo
- Publication number
- JPH0961142A JPH0961142A JP7221789A JP22178995A JPH0961142A JP H0961142 A JPH0961142 A JP H0961142A JP 7221789 A JP7221789 A JP 7221789A JP 22178995 A JP22178995 A JP 22178995A JP H0961142 A JPH0961142 A JP H0961142A
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- electron
- energy
- film thickness
- electrons
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、分子線エピタキシーな
どの真空蒸着法による成膜中に、試料の膜厚を１原子層
厚以下の精度で計測する方法および装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring the film thickness of a sample with a precision of one atomic layer or less during film formation by a vacuum evaporation method such as molecular beam epitaxy.
【０００２】[0002]
【従来の技術】真空蒸着法により試料を成膜する際、２
次電子の強度が１原子層厚の周期で振動する現象を利用
することが可能だと考えられるが、この現象は、従来、
反射高速電子回折の実験条件で観測されており、ジャー
ナル・オブ・クリスタル・グロウス（Journal of Cryst
al Growth）81巻（1987年）55頁から58頁に報告されて
いる。2. Description of the Related Art When depositing a sample by a vacuum deposition method, 2
It is possible to use the phenomenon that the intensity of the secondary electron oscillates in a cycle of one atomic layer thickness.
Observed under the experimental conditions of reflection high-energy electron diffraction, the Journal of Cryst (Journal of Cryst
al Growth) 81 (1987) 55-58.
【０００３】[0003]
【発明が解決しようとする課題】しかし、上記方法は、
１次電子を試料表面すれすれ（試料表面から測って、電
子の全反射角程度以下。以下、角度はすべて試料表面か
ら測るものとする）に入射させることを必要とするた
め、電子の試料への入射を妨げないような特殊な試料
台、および１次電子の入射角を調整するための機構が試
料台もしくは電子銃に必要となるため、装置全体が大型
化および複雑化し、これによって装置の取扱が困難にな
る欠点および装置全体の価格が高価になる欠点があっ
た。However, the above method is
Since it is necessary to make primary electrons strike the surface of the sample (measured from the surface of the sample, less than or equal to the total reflection angle of the electrons; hereinafter, all angles are measured from the surface of the sample), it is necessary for the electrons to enter the sample. Since a special sample stand that does not obstruct the incidence and a mechanism for adjusting the incident angle of the primary electrons are required for the sample stand or the electron gun, the overall size of the device becomes large and complicated, and the handling of the device is thereby performed. However, there is a drawback in that the cost of the entire apparatus is high.
【０００４】発明が解決しようとする課題は、安価で構
造が単純かつコンパクトな装置を用いて、真空蒸着によ
る成膜中の試料の膜厚を１原子層厚以下の精度で測定お
よび制御することにある。The problem to be solved by the invention is to measure and control the film thickness of a sample during film formation by vacuum vapor deposition with an accuracy of one atomic layer or less using an inexpensive, simple and compact device. It is in.
【０００５】[0005]
【課題を解決するための手段】上記の問題点は、１次電
子の試料への入射角を全反射角よりも大きな角度とする
ことで解決できる。The above problems can be solved by setting the incident angle of the primary electrons to the sample to be larger than the total reflection angle.
【０００６】[0006]
【作用】従来の技術において、反射高速電子回折の実験
条件で観測されている２次電子の強度振動は、サーフェ
イス・サイエンス・レターズ（Surface Science Letter
s）245巻（1991年）L159頁からL162頁に解説されている
内容を用いて、次のように説明できる。In the conventional technique, the intensity vibration of the secondary electron observed under the experimental condition of the reflection high-energy electron diffraction is the surface science letter (Surface Science Letter).
s) Volume 245 (1991) L159 to L162 can be explained as follows using the contents explained.
【０００７】真空蒸着中の試料が層状成長している場
合、その表面に形成されるステップの密度は１原子層周
期で振動する。１次電子を試料に全反射角以内の角度で
入射させても、試料表面にステップが存在する場合、そ
の端から電子は試料内に侵入できる。侵入した電子の一
部は試料内部での回折によって表面へ向うが、さらにそ
の一部が試料表面での全反射によって再び試料内部に向
い吸収される。よってステップ密度が振動すれば試料に
吸収される電子数も振動することになる。２次電子数は
１次電子数と試料に吸収される電子数の差であるから、
試料に吸収される電子数が変化すれば、２次電子強度も
変化することになる。When the sample being vacuum-deposited grows in layers, the density of steps formed on the surface of the sample oscillates in one atomic layer period. Even if the primary electron is incident on the sample at an angle within the total reflection angle, if a step exists on the sample surface, the electron can penetrate into the sample from the end. A part of the invading electrons goes to the surface due to diffraction inside the sample, and a part of the electron is again absorbed toward the inside of the sample by the total reflection at the sample surface. Therefore, if the step density vibrates, the number of electrons absorbed by the sample also vibrates. Since the number of secondary electrons is the difference between the number of primary electrons and the number of electrons absorbed by the sample,
If the number of electrons absorbed by the sample changes, the secondary electron intensity also changes.
【０００８】以上により従来の技術では、１次電子の試
料への入射角が全反射角よりも大きい場合、２次電子振
動は観測されない、と考えられてきた。As described above, it has been considered that in the conventional technique, when the incident angle of the primary electron on the sample is larger than the total reflection angle, the secondary electron vibration is not observed.
【０００９】しかし、発明者の研究結果によれば、次の
原理により、１次電子の試料への入射角が全反射角より
も大きい場合でも、２次電子振動が観測され得る。すな
わち、２次電子の収率は試料表面の仕事関数が小さいと
大きくなるから、仕事関数が振動すれば２次電子強度も
振動することになる。蒸着中の試料表面の仕事関数の振
動は、サーフェイス・サイエンス（Surface Science）2
98巻（1993年）173頁から186頁に解説されている。However, according to the research results of the inventor, secondary electron vibration can be observed according to the following principle even when the angle of incidence of primary electrons on the sample is larger than the angle of total reflection. That is, the yield of secondary electrons increases when the work function of the sample surface is small. Therefore, if the work function oscillates, the intensity of the secondary electrons also oscillates. The vibration of the work function of the sample surface during vapor deposition is due to surface science (Surface Science) 2.
Volume 98 (1993) pp.173-186.
【００１０】また、同じ現象を次のように説明すること
もできる。すなわち、基板上に試料を蒸着する場合、試
料が薄膜であるとその中に量子井戸が形成される。この
量子井戸状態は試料と基板の界面および試料表面の２つ
の境界条件で規定される。ここで前者の境界条件は試料
膜厚に依存しないと考えられるが、後者の境界条件であ
る表面形状（荒さ）はステップ密度に応じて１原子層周
期で変化し、薄膜試料内の電子の状態密度、したがって
これを反映する２次電子強度もこの周期で変化する。The same phenomenon can also be explained as follows. That is, when the sample is vapor-deposited on the substrate, the quantum well is formed in the sample if the sample is a thin film. This quantum well state is defined by two boundary conditions of the interface between the sample and the substrate and the sample surface. Here, it is considered that the former boundary condition does not depend on the sample film thickness, but the latter boundary condition, the surface shape (roughness), changes with one atomic layer period according to the step density, and the electron state in the thin film sample The density, and thus the secondary electron intensity that reflects this, also changes in this cycle.
【００１１】発明者のこの研究結果によれば、１次電子
の試料への入射角が全反射角よりも大きい場合でも、基
板への試料の蒸着中に、２次電子振動が試料の層成長の
周期と同期して振動するので、これにより蒸着中の試料
の膜厚を１原子層厚以下の精度で知ることが可能とな
る。ここで、１次電子のエネルギーは、２次電子励起が
可能となる最低のエネルギーである10eV程度よりも大き
ければ、特に制約はない。According to the results of this research conducted by the inventor, even when the incident angle of primary electrons on the sample is larger than the total reflection angle, secondary electron vibration causes layer growth of the sample during the deposition of the sample on the substrate. Since it vibrates in synchronism with the cycle of, the film thickness of the sample during vapor deposition can be known with an accuracy of one atomic layer thickness or less. Here, the energy of the primary electron is not particularly limited as long as it is larger than about 10 eV which is the lowest energy at which the secondary electron can be excited.
【００１２】[0012]
【実施例】図１は本発明による膜厚測定装置の実施例の
第一の基本構成を示す図である。本構成は基板11、およ
びこの基板11に１次電子を照射するための電子銃12、基
板11上に試料を蒸着する蒸着装置13、１次電子によりた
たき出された２次電子の強度を測定するための２次電子
検出器14からなる。ここで電子銃12は１次電子のエネル
ギーを10eV程度から5keV程度まで自由に設定できる機能
を持つものとする。また、１次電子の試料への入射角は
全反射角よりも大きければ、特に制約はない。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the first basic construction of an embodiment of the film thickness measuring apparatus according to the present invention. This configuration measures a substrate 11, an electron gun 12 for irradiating the substrate 11 with primary electrons, a vapor deposition device 13 for depositing a sample on the substrate 11, and the intensity of secondary electrons hit by the primary electrons. It comprises a secondary electron detector 14 for Here, it is assumed that the electron gun 12 has a function of freely setting the energy of primary electrons from about 10 eV to about 5 keV. Further, there is no particular limitation as long as the angle of incidence of the primary electrons on the sample is larger than the angle of total reflection.
【００１３】この構成では、基板11上に蒸着装置13を用
いて試料を蒸着しながら、電子銃12によって約1keVのエ
ネルギーを有する１次電子を照射する。このとき基板11
上に形成された薄膜試料表面から放出される２次電子の
強度を２次電子検出器14により測定する。測定された２
次電子強度は基板11上に形成される試料の膜厚の関数と
して１原子層の周期で振動する。試料として金を蒸着し
たときの２次電子強度の振動を図２に示す。この振動の
周期Ｔは試料の１原子層の厚さに等しいため、横軸であ
る金の厚さをＴで校正でき、正確な金薄膜の厚さがわか
る。従って、この現象を用いることで高精度の膜厚計測
が可能となる。In this structure, the electron gun 12 irradiates primary electrons having an energy of about 1 keV while depositing a sample on the substrate 11 using the vapor deposition device 13. At this time, the substrate 11
A secondary electron detector 14 measures the intensity of secondary electrons emitted from the surface of the thin film sample formed above. Measured 2
The secondary electron intensity oscillates with a period of one atomic layer as a function of the film thickness of the sample formed on the substrate 11. The vibration of the secondary electron intensity when gold is vapor-deposited as a sample is shown in FIG. Since the period T of this vibration is equal to the thickness of one atomic layer of the sample, the thickness of gold on the horizontal axis can be calibrated by T, and the accurate thickness of the gold thin film can be known. Therefore, by using this phenomenon, highly accurate film thickness measurement becomes possible.
【００１４】さらに、２次電子強度振動が最も顕著に現
れる１次電子のエネルギーは試料の種類や面方位などに
よって異なる場合がある。本実施例では例として１次電
子のエネルギーを1keV程度としたが、試料の種類や面方
位に応じて１次電子のエネルギーを変えることで、２次
電子強度振動が最も顕著に現れる最適の条件で本方法を
用いればよい。Further, the energy of the primary electrons in which the secondary electron intensity vibration is most prominent may differ depending on the type of sample and the plane orientation. In the present embodiment, the energy of the primary electron is set to about 1 keV as an example, but the optimal condition under which the secondary electron intensity oscillation appears most remarkably by changing the energy of the primary electron according to the type of sample and the plane orientation. Then, this method may be used.
【００１５】図３は本発明による膜厚測定装置の実施例
の第二の基本構成を示す図である。本構成は基板11、お
よびこの基板11に１次電子を照射するための電子銃12、
基板11上に試料を蒸着する蒸着装置13、１次電子により
たたき出された２次電子を収集し効率よく伝送するため
の電子レンズ31、２次電子のエネルギーを選別するため
のエネルギー分析器32、エネルギー分析された後の２次
電子強度を測定するための２次電子検出器14からなる。
さらに電子銃12は第一の実施例と同様に、１次電子のエ
ネルギーを10eV程度から5keV程度まで自由に設定できる
機能を持つものとする。また、第一の実施例と同様に、
１次電子の試料への入射角は全反射角よりも大きけれ
ば、特に制約はない。FIG. 3 is a diagram showing the second basic construction of the embodiment of the film thickness measuring apparatus according to the present invention. This configuration has a substrate 11, an electron gun 12 for irradiating the substrate 11 with primary electrons,
A vapor deposition apparatus 13 for depositing a sample on a substrate 11, an electron lens 31 for collecting and efficiently transmitting secondary electrons hit by primary electrons, and an energy analyzer 32 for selecting energy of secondary electrons. , A secondary electron detector 14 for measuring the secondary electron intensity after energy analysis.
Further, the electron gun 12 has a function of freely setting the energy of primary electrons from about 10 eV to about 5 keV, as in the first embodiment. Also, as in the first embodiment,
There is no particular limitation as long as the incident angle of the primary electron on the sample is larger than the total reflection angle.
【００１６】この構成では、基板11上に蒸着装置13によ
り試料を蒸着しながら、電子銃12によって約1keVのエネ
ルギーを有する１次電子を照射する。このとき基板11上
に形成された薄膜試料表面から放出される２次電子を電
子レンズ31によって収集し、エネルギー分析器32へ効率
よく伝送する。エネルギー分析器32に入射した２次電子
のうち特定のエネルギーを持った電子だけが２次電子検
出器14に導かれ、その強度が測定される。測定された２
次電子強度は第一の実施例と同様に、基板11上に形成さ
れる試料の膜厚の関数として振動し、その振動の周期Ｔ
が試料の１原子層の厚さに等しいため、この振動をモニ
タすることで高精度の膜厚計測が可能となる。In this structure, the electron gun 12 irradiates primary electrons having an energy of about 1 keV while depositing a sample on the substrate 11 by the vapor deposition device 13. At this time, secondary electrons emitted from the surface of the thin film sample formed on the substrate 11 are collected by the electron lens 31 and efficiently transmitted to the energy analyzer 32. Of the secondary electrons incident on the energy analyzer 32, only the electrons having a specific energy are guided to the secondary electron detector 14 and the intensity thereof is measured. Measured 2
The secondary electron intensity oscillates as a function of the film thickness of the sample formed on the substrate 11 as in the first embodiment, and the oscillation period T
Is equal to the thickness of one atomic layer of the sample, so that the film thickness can be measured with high accuracy by monitoring this vibration.
【００１７】さらに、２次電子強度振動が最も顕著に現
れる２次電子のエネルギー範囲は試料の種類や面方位な
どによって異なる場合がある。本実施例ではエネルギー
分析器32によって特定のエネルギーを持った２次電子だ
けを２次電子検出器14に導くことができるので、これに
より２次電子強度振動が最も顕著に現れるエネルギーを
選び、その２次電子の強度を測定すればよい。Furthermore, the energy range of the secondary electrons in which the secondary electron intensity oscillations are most prominent may differ depending on the type of sample and the plane orientation. In this embodiment, only the secondary electrons having a specific energy can be guided to the secondary electron detector 14 by the energy analyzer 32. Therefore, the energy at which the secondary electron intensity oscillation is most prominent is selected, and The intensity of secondary electrons may be measured.
【００１８】さらに、第一の実施例と同様に、２次電子
強度振動が最も顕著に現れる１次電子のエネルギーは試
料の種類や面方位などによって異なる場合があるため、
本実施例でも試料の種類や面方位に応じて１次電子のエ
ネルギーを調整することで、２次電子強度振動が最も顕
著に現れる最適の条件で本方法を用いればよい。Further, as in the first embodiment, the energy of the primary electrons in which the secondary electron intensity vibrations most significantly appear may differ depending on the type of sample, the plane orientation, etc.
Also in the present embodiment, the method may be used under the optimum conditions in which the secondary electron intensity oscillation appears most remarkably by adjusting the energy of the primary electrons according to the type of sample and the plane orientation.
【００１９】図４は本発明による膜厚測定装置の実施例
の第三の基本構成を示す図である。本構成は基板11、お
よびこの基板11に１次電子を照射するための電子銃12、
基板11上に試料を蒸着する蒸着装置13からなる。さらに
電子銃12は第一の実施例と同様に、１次電子のエネルギ
ーを10eV程度から5keV程度まで自由に設定できる機能を
持つものとする。また、第一の実施例と同様に、１次電
子の試料への入射角は全反射角よりも大きければ、特に
制約はない。FIG. 4 is a diagram showing a third basic construction of the embodiment of the film thickness measuring apparatus according to the present invention. This configuration has a substrate 11, an electron gun 12 for irradiating the substrate 11 with primary electrons,
It comprises a vapor deposition device 13 for vapor depositing a sample on a substrate 11. Further, the electron gun 12 has a function of freely setting the energy of primary electrons from about 10 eV to about 5 keV, as in the first embodiment. Further, as in the first embodiment, there is no particular limitation as long as the incident angle of the primary electron on the sample is larger than the total reflection angle.
【００２０】この構成では、基板11上に蒸着装置13を用
いて試料を蒸着しながら、電子銃12によって約1keVのエ
ネルギーを有する１次電子を照射する。このとき基板11
において測定される吸収電流は基板11上に形成される試
料の膜厚の関数として１原子層の周期で振動する。この
振動の様子は図２に示した２次電子強度の振動と同様で
ある。この振動の周期Ｔは２次電子強度の振動の周期と
同じく試料の１原子層の厚さに等しいため、横軸である
金の厚さをＴで校正でき、正確な金薄膜の厚さがわか
る。従って、この現象を用いることでも高精度の膜厚計
測が可能となる。本実施例では第一の実施例とは異な
り、２次電子検出器を必要としないので、より簡便な膜
厚計測装置の実現が可能となる。In this structure, the electron gun 12 irradiates primary electrons having an energy of about 1 keV while depositing a sample on the substrate 11 using the vapor deposition device 13. At this time, the substrate 11
The absorption current measured at oscillates with a period of one atomic layer as a function of the film thickness of the sample formed on the substrate 11. This vibration is similar to the vibration of the secondary electron intensity shown in FIG. Since the period T of this vibration is equal to the thickness of one atomic layer of the sample like the period of the vibration of the secondary electron intensity, the thickness of gold on the horizontal axis can be calibrated with T, and the accurate thickness of the gold thin film can be obtained. Recognize. Therefore, by using this phenomenon, the film thickness can be measured with high accuracy. Unlike the first embodiment, this embodiment does not require a secondary electron detector, so that a simpler film thickness measuring device can be realized.
【００２１】さらに、吸収電流振動が最も顕著に現れる
１次電子のエネルギーは２次電子強度振動と同様に、試
料の種類や面方位などによって異なる場合がある。本実
施例では例として１次電子のエネルギーを1keV程度とし
たが、試料の種類や面方位に応じて１次電子のエネルギ
ーを変えることで、吸収電流振動が最も顕著に現れる最
適の条件で本方法を用いればよい。Further, the energy of the primary electrons in which the absorption current vibration most remarkably appears may vary depending on the type of sample, the plane orientation, etc., as in the secondary electron intensity vibration. In the present embodiment, the energy of the primary electron was set to about 1 keV as an example, but by changing the energy of the primary electron according to the type of sample and the plane orientation, the absorption current oscillation becomes most remarkable under the optimum conditions. Any method may be used.
【００２２】図５は本発明による膜厚測定装置の実施例
の第四の基本構成を示す図である。本構成は基板11、お
よびこの基板11に１次電子を照射するための電子銃12、
基板11上に試料を蒸着する蒸着装置13、１次電子により
たたき出された２次電子の強度を測定するための２次電
子検出器14、およびこれら装置の制御とデータ収集を行
うためのコンピュータ51からなる。さらに電子銃12は第
一の実施例と同様に、１次電子のエネルギーを10eV程度
から5keV程度まで自由に設定できる機能を持つものとす
る。また、第一の実施例と同様に、１次電子の試料への
入射角は全反射角よりも大きければ、特に制約はない。FIG. 5 is a diagram showing the fourth basic construction of the embodiment of the film thickness measuring apparatus according to the present invention. This configuration has a substrate 11, an electron gun 12 for irradiating the substrate 11 with primary electrons,
A deposition device 13 for depositing a sample on a substrate 11, a secondary electron detector 14 for measuring the intensity of secondary electrons hit by primary electrons, and a computer for controlling these devices and collecting data. It consists of 51. Further, the electron gun 12 has a function of freely setting the energy of primary electrons from about 10 eV to about 5 keV, as in the first embodiment. Further, as in the first embodiment, there is no particular limitation as long as the incident angle of the primary electron on the sample is larger than the total reflection angle.
【００２３】この構成では、基板11上に蒸着装置13によ
り試料を蒸着しながら、電子銃12によって約1keVのエネ
ルギーを有する１次電子を照射する。このとき基板11上
に形成された薄膜試料表面から放出される２次電子の強
度を２次電子検出器13により測定する。測定された２次
電子強度は第一の実施例と同様に、基板11上に形成され
る試料の膜厚の関数として振動し、その振動の周期Ｔが
試料の１原子層の厚さに等しいため、これにより高精度
の膜厚計測が可能となる。この２次電子強度振動の信号
をコンピュータ51によりモニタすることで、膜厚測定が
自動化される。In this structure, the electron gun 12 irradiates primary electrons having an energy of about 1 keV while depositing the sample on the substrate 11 by the vapor deposition device 13. At this time, the intensity of secondary electrons emitted from the surface of the thin film sample formed on the substrate 11 is measured by the secondary electron detector 13. The measured secondary electron intensity oscillates as a function of the film thickness of the sample formed on the substrate 11 as in the first embodiment, and the period T of the oscillation is equal to the thickness of one atomic layer of the sample. Therefore, this enables highly accurate film thickness measurement. By monitoring the signal of this secondary electron intensity vibration by the computer 51, the film thickness measurement is automated.
【００２４】さらに、本実施例では第一の実施例と同様
に、２次電子強度振動が最も顕著に現れる１次電子のエ
ネルギーは試料の種類や面方位などによって異なる場合
があるため、本実施例でも試料の種類や面方位に応じて
１次電子のエネルギーを調整することで、２次電子強度
振動が最も顕著に現れる最適の条件で本方法を用いれば
よい。このとき２次電子強度振動測定および電子銃12の
制御をコンピュータ５１で行うことにより自動化が可能
となる。Further, in the present embodiment, as in the first embodiment, the energy of the primary electrons in which the secondary electron intensity oscillations are most prominent may differ depending on the type of sample and the plane orientation. Even in the example, the present method may be used under the optimum condition in which the secondary electron intensity oscillation appears most remarkably by adjusting the energy of the primary electron according to the type of sample and the plane orientation. At this time, the secondary electron intensity vibration measurement and the control of the electron gun 12 are performed by the computer 51, whereby automation becomes possible.
【００２５】さらに、本実施例では蒸着時間に対する膜
厚をコンピュータ５１でモニタし、その蒸着速度が任意
の速度になるように蒸着装置13を制御することにより、
蒸着速度制御を自動化できる。Further, in this embodiment, the film thickness with respect to the vapor deposition time is monitored by the computer 51, and the vapor deposition apparatus 13 is controlled so that the vapor deposition rate becomes an arbitrary rate.
The deposition rate control can be automated.
【００２６】さらに、本実施例では蒸着時間に対する膜
厚をコンピュータ51でモニタし、目的とする膜厚が得ら
れたところで蒸着をコンピュータ51により自動停止する
ことで、任意の膜厚の試料作製が自動的にできる。この
とき目的とする膜厚の情報はあらかじめコンピュータ51
に入力しておけばよい。Further, in the present embodiment, the film thickness with respect to the vapor deposition time is monitored by the computer 51, and when the target film thickness is obtained, the computer 51 automatically stops the vapor deposition to prepare a sample having an arbitrary film thickness. You can do it automatically. At this time, the information on the target film thickness is previously stored in the computer 51.
You can enter it in.
【００２７】さらに、２次電子強度振動が最も顕著に現
れる２次電子のエネルギー範囲は試料の種類や面方位な
どによって異なる場合がある。従って本実施例でも第二
の実施例と同様に、エネルギー分析器を利用することで
特定のエネルギーを持った２次電子だけを２次電子検出
器14に導き、その２次電子の強度を測定すればよい。こ
のエネルギー選別もコンピュータ51により自動化するこ
とができる。Further, the energy range of the secondary electrons in which the secondary electron intensity vibrations are most prominent may differ depending on the type of sample and the plane orientation. Therefore, also in this embodiment, as in the second embodiment, by using the energy analyzer, only the secondary electrons having a specific energy are guided to the secondary electron detector 14 and the intensity of the secondary electrons is measured. do it. This energy selection can also be automated by the computer 51.
【００２８】さらに、本実施例では２次電子強度振動を
利用したが、第四の実施例に示した吸収電流振動を利用
することもできる。この場合、２次電子検出器14は不要
となり、装置全体の構成はさらに簡便なものとなる。Further, although the secondary electron intensity vibration is used in this embodiment, the absorption current vibration shown in the fourth embodiment can also be used. In this case, the secondary electron detector 14 is not needed, and the configuration of the entire device becomes simpler.
【００２９】なお、上述の説明では、試料に対する電子
線の照射は、試料の全面に対して行なうこととしたが、
電子線を絞って、試料の特定の領域での膜厚測定とする
場合でも同様に実施できる。In the above description, the irradiation of the sample with the electron beam is performed on the entire surface of the sample.
The same operation can be performed when the electron beam is focused to measure the film thickness in a specific region of the sample.
【００３０】[0030]
【発明の効果】本発明によれば、１次電子の入射角を全
反射角よりも大きくして試料に照射することで、真空蒸
着による成膜中の試料の膜厚を１原子層厚以下の精度で
測定および制御できるので、装置全体の構成が簡略化さ
れ、取り扱いが容易になり装置全体の価格も安価となる
効果がある。さらに本発明によれば、反射高速電子回折
を用いた従来装置よりも構造が比較的簡単な低エネルギ
ー用の電子銃を用いているため、専用の高電圧電源や電
子銃、電子光学系を用いるのに比べ装置全体が安価なシ
ステムとなる効果がある。これらの効果の学術分野への
応用、さらにはその工業的価値は非常に高いものであ
る。According to the present invention, by irradiating the sample with the incident angle of the primary electrons being larger than the total reflection angle, the film thickness of the sample during film formation by vacuum evaporation is one atomic layer or less. Since the measurement and control can be performed with the accuracy of, the configuration of the entire apparatus is simplified, the handling is easy, and the price of the entire apparatus is low. Further, according to the present invention, since an electron gun for low energy having a relatively simple structure is used as compared with the conventional apparatus using reflection high-energy electron diffraction, a dedicated high voltage power source, electron gun, and electron optical system are used. Compared with the above, there is an effect that the entire apparatus becomes a cheap system. The application of these effects to academic fields and their industrial value are extremely high.
【図１】本発明の基本構成を表す図。FIG. 1 is a diagram showing a basic configuration of the present invention.
【図２】本発明により得られた２次電子強度振動の図。FIG. 2 is a diagram of secondary electron intensity vibration obtained by the present invention.
【図３】本発明とエネルギー分析器の組み合わせを示す
図。FIG. 3 is a diagram showing a combination of the present invention and an energy analyzer.
【図４】本発明に吸収電流振動を利用した場合の構成を
表す図。FIG. 4 is a diagram showing a configuration in which absorption current oscillation is used in the present invention.
【図５】本発明とコンピュータによる蒸着の自動制御を
示す図。FIG. 5 is a diagram showing the present invention and automatic control of vapor deposition by a computer.
11・・・基板、12・・・電子銃、13・・・蒸着装置、14・・・２次電
子検出器、31・・・電子レンズ、32・・・エネルギー分析器、
51・・・コンピュータ。11 ... Substrate, 12 ... Electron gun, 13 ... Vapor deposition apparatus, 14 ... Secondary electron detector, 31 ... Electron lens, 32 ... Energy analyzer,
51 ... computer.
Claims (7)
面へ１次電子を照射することにより放出される２次電子
の強度が、試料の膜厚の関数として１原子層厚の周期で
振動する現象を利用した膜厚測定法において、１次電子
の試料表面から測った入射角を、電子の試料に対する全
反射角よりも大きくすることを特徴とする膜厚計測法。1. The intensity of secondary electrons emitted by irradiating the surface of a sample with primary electrons during thin film sample preparation by vacuum evaporation oscillates at a period of one atomic layer thickness as a function of the film thickness of the sample. In the film thickness measuring method utilizing the phenomenon described above, the incident angle of the primary electron measured from the sample surface is made larger than the total reflection angle of the electron with respect to the sample.
て現れる試料への吸収電流振動を利用する請求項１記載
の膜厚計測法。2. The film thickness measuring method according to claim 1, wherein the absorption current vibration to the sample, which appears under the condition that the intensity vibration of the secondary electron is obtained, is used.
をエネルギー分析器によって選別することにより、振動
が最も明瞭にあらわれるエネルギーを持った２次電子だ
けを用いる請求項１記載の膜厚計測法。3. The film thickness measuring method according to claim 1, wherein only the secondary electrons having the energy in which the vibration appears most clearly are selected by selecting the energy of the secondary electrons for intensity vibration measurement by an energy analyzer. .
２次電子強度振動もしくは吸収電流振動が最も明瞭に現
れる１次電子のエネルギーを選別して利用する請求項１
もしくは請求項２記載の膜厚計測法。4. The primary electron energy is set to an arbitrary value and the energy of the primary electron in which the secondary electron intensity oscillation or the absorption current oscillation appears most clearly is selected and used.
Alternatively, the film thickness measuring method according to claim 2.
るための基板、前記試料表面へ１次電子を照射する電子
銃、前記１次電子の照射により試料表面より放出される
２次電子を検出する２次電子検出器を備え、前記電子銃
の試料表面への１次電子の照射角が試料表面から見て全
反射角より大きい角度となるように設定されていること
を特徴とする膜厚計測装置。5. A substrate for forming a thin film sample by vacuum deposition on the surface, an electron gun for irradiating the sample surface with primary electrons, and secondary electrons emitted from the sample surface by irradiation with the primary electrons. A film comprising a secondary electron detector for detecting, and the irradiation angle of the primary electrons on the sample surface of the electron gun is set to be larger than the total reflection angle when viewed from the sample surface. Thickness measuring device.
振動を検出する請求項５記載の膜厚計測装置。6. The film thickness measuring device according to claim 5, wherein the absorption current oscillation in the sample is detected instead of the secondary electrons.
ためのエネルギー分析器を備える請求項５記載の膜厚計
測装置。7. The film thickness measuring device according to claim 5, further comprising an energy analyzer for analyzing the energy of the detected secondary electrons.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7221789A JPH0961142A (en) | 1995-08-30 | 1995-08-30 | Method and apparatus for measurement of film thickness |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7221789A JPH0961142A (en) | 1995-08-30 | 1995-08-30 | Method and apparatus for measurement of film thickness |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0961142A true JPH0961142A (en) | 1997-03-07 |
Family
ID=16772235
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7221789A Pending JPH0961142A (en) | 1995-08-30 | 1995-08-30 | Method and apparatus for measurement of film thickness |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0961142A (en) |
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