JP2002110079A - Electron beam device - Google Patents

Abstract

(57) [Summary] In an in-lens scanning electron microscope, three types of secondary signals (SE, BS) having different sample information are included.
E_L, BSE_H) are added at arbitrary ratios to generate sample signals. A plurality of signal conversion means for converting reflected electrons generated from a sample at different angles into secondary electrons by collision, respectively, and detecting the secondary electrons by the signal conversion means and a secondary electron signal generated from the sample. A plurality of detection means,
A plurality of signal control means for controlling a detection amount of secondary electrons generated from the sample and a signal addition means for adding signals of the plurality of signal detection means are provided. [Effect] It is possible to select a sample signal according to the observation purpose.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam apparatus,
In particular, the present invention relates to an electron beam apparatus suitable for effectively synthesizing various sample signals and obtaining a high-contrast sample image particularly at a low acceleration voltage.

[0002]

2. Description of the Related Art Among high-energy signal electrons (reflected electrons) generated from a sample, reflected electrons contained in different emission cone angles from the sample and low-energy signal electrons (secondary electrons) generated from the sample are: Many methods have been proposed for the detection of these signals in order to provide important sample information having different properties.

For example, in US Pat. No. 5,493,116, a backscattered electron detector for directly detecting backscattered electrons contained in a large cone angle is disposed at the tip of a magnetic pole of an objective lens, and an accelerated secondary electron beam is located closer to the electron source than the objective lens. An example is disclosed in which a detector for simultaneously detecting electrons and reflected electrons contained in a small cone angle is arranged.

[0004] PCT / J98 / 04297 discloses an example in which signal conversion electrodes are arranged at two places and two signal detectors are arranged to detect secondary electrons generated from each conversion electrode. ing. PCT / J98 / 04297
Discloses that secondary electrons generated from a sample are detected by a detector close to the objective lens among the two detectors.

In PCT / JP97 / 03385, a reflected electron detector for directly detecting reflected electrons on the electron source side of the objective lens and on the objective lens side of the secondary electron detecting means, and an electron on the electron source side of the secondary electron detecting means. There is disclosed a detecting means for converting reflected electrons having a small cone angle into secondary electrons and detecting them at the source side.

In Japanese Patent Application Laid-Open No. 2000-30654, a reflected electron detector for directly detecting reflected electrons is disposed on the other side of the objective lens on the electron source side of the objective lens, and two reflected electrons are located on the electron source side. An example is disclosed in which a secondary electron conversion electrode for converting to secondary electrons and a detector for detecting secondary electrons generated from the secondary electron conversion electrode are arranged.

In Japanese Patent Application Laid-Open No. Hei 9-171791, a secondary electron conversion electrode and a detector for detecting a signal generated from the conversion electrode are arranged at two positions along the optical axis on the electron source side of the objective lens. A detection means combining these is shown.

[0008]

The prior arts disclosed in the above references each have problems (problems) as described below.

The technique disclosed in US Pat. No. 5,493,116 is:
In this configuration, a reflected electron having a small cone angle and a secondary electron (SE signal) generated from the sample are simultaneously detected by a detector arranged further on the electron source side than the beam scanning means.
In this disclosed technique, it is assumed that the sample is operated by applying a negative voltage (retarding voltage) to the sample.
When a retarding voltage is not applied, secondary electrons are not accelerated, and sufficient secondary electron detection efficiency cannot be obtained. Therefore, when the retarding voltage is not applied, it is impossible to generate a signal in which the reflected electron information and the secondary electron information are combined at an arbitrary different ratio in the present disclosure. Further, in the present disclosure, since the detection of reflected electrons included in a large cone angle is directly detected without being converted into secondary electrons, it is necessary to obtain reflected electron information at a low acceleration voltage when retarding is not performed. It is essential to use MCP (multi-channel plate)
Compared to the method of detecting by converting to secondary electrons, problems such as the short life of the detector itself are inevitable.

In the technique disclosed in PCT / J98 / 04297, it is possible to detect reflected electron information and secondary electron information of different cone angles even in a situation where a retarding voltage is not applied. However, in the present disclosure, there is no description about combining a plurality of reflected electron signals with different cone angles and secondary electron signals at different arbitrary ratios.

In the technique disclosed in PCT / JP97 / 03385, the present invention does not deal with combining a plurality of reflected electron signals and secondary electron signals having different cone angles at different arbitrary ratios. There is no description. Further, in the present disclosure, since the detection of reflected electrons included in a large cone angle is directly detected without being converted into secondary electrons, it is necessary to obtain reflected electron information at a low acceleration voltage when retarding is not performed. It is essential to use MCP (multi-channel plate)
Compared to the method of converting to secondary electrons, problems such as a shorter life of the detector itself are inevitable.

In the technology disclosed in Japanese Patent Application Laid-Open No. 9-171791, when retarding is not performed, reflected electron information having a small cone angle is detected by a detector arranged on the electron source side, and is detected by a detector arranged on the objective lens side. Relatively large reflected electron information and secondary electron information of the cone angle can be detected. However, since consideration is not given to controlling the detection efficiency of the reflected electron information and the secondary electron information by the detector on the objective lens side, the reflected electron information and the secondary electron information of a large cone angle are detected at an arbitrary ratio. Therefore, the effects intended by the present invention cannot be realized.

An example showing a difference in image information between a signal of a secondary electron having a low energy and a signal of a reflected electron having a high energy and a different cone angle (a sample: a catalyst material containing platinum particles inside carbon; Voltage: 2k
V) is shown in FIG. The secondary electron signal (SE signal) having low energy has an advantage that a fine structure on the outermost surface of the sample can be obtained with high spatial resolution. On the other hand, the backscattered electrons (BSE_L signal) having a large cone angle contain a relatively large amount of surface information in addition to internal information and composition information. For example, even if the fine structure of the sample is erased due to the strong edge contrast with the secondary electrons, the use of the reflected electron signal (BSE_L signal) having a large cone angle can provide surface information with suppressed edge contrast. There are advantages. In addition, the reflected electron signal (BSE_H signal) having a small cone angle has a merit that the surface information of the sample is poor, but it is sensitive to the composition information (high contrast), and the spatial resolution of the signal information is relatively high at a low acceleration voltage. is there. Thus, the reflected electrons (BSE_L, BSE_
H) In order to make the most of the difference between the characteristics of information and secondary electron (SE) information, it is very important to add and combine these signals at different ratios depending on the purpose in order to obtain the optimal sample information. It is effective for Further, when utilizing the backscattered electron information, the lower the energy of the primary electron beam, the smaller the scattering region of the primary electrons in the sample, so that the backscattered electron information with high spatial resolution can be obtained.

In the present invention, the above-mentioned problems of the prior art are solved, and reflected electron signals (BSE_L signal, BSE_H signal) having different cone angles, especially at a low acceleration voltage.
And a secondary electron signal (SE signal) directly generated from the sample are added at an arbitrary ratio to generate an optimal sample signal according to the observation purpose, and a long-life scintillator and photomultiplier are used as a signal electron detector. The purpose of the present invention is to provide an apparatus using a detection method combining priors.

[0015]

Means for achieving the above object will be described with reference to FIGS. 1 to 4. Reflected electron information (BSE_L, BS) of different cone angles generated from the sample by irradiation of the primary electron beam 5 with a low acceleration voltage
In order to detect E_H), a plurality of electrodes (electrodes) for secondary electron conversion for converting reflected electrons into secondary electrons are provided at at least two positions along the optical axis closer to the electron source than the objective lens. (1) 30 and electrodes (2) 32) are arranged. Since the generation efficiency of secondary electrons is maximized when the energy of signal electrons colliding with the secondary electron conversion electrode is several keV or less, reflected electrons in this energy region collide with the electrode (1) 30 and the electrode (2) 32. Sometimes, the amount of secondary electrons generated from the electrode (corresponding to the detection sensitivity of reflected electrons) is maximized. Since the sample 11 is disposed inside the magnetic field 10a of the objective lens 10, as shown in FIG. 2, the reflected electrons 24 generated from the sample are strongly converged by the objective lens magnetic field. At this time, the reflected electrons having different emission angles (cone angles) from the sample converge to different points on the optical axis due to the influence of the spherical aberration of the objective lens. Therefore, the secondary electron conversion electrode (1) 30 and the electrode (2) By arranging 32 at different positions along the optical axis, the backscattered electrons (BSL_) having a large cone angle can be obtained at the electrode (1) close to the objective lens.
L) is converted into secondary electrons, and the reflected electrons (BSE_) having a small cone angle are reflected at the electrode (2) far from the objective lens.
H) is converted to secondary electrons. In an in-lens scanning electron microscope in which the sample is placed in the magnetic field of the objective lens,
By arranging the electrode (1) on the upper magnetic pole of the objective lens 10, the electrode (1) can convert the reflected electrons (BSE_L) having a large cone angle into secondary electrons. Further, by providing the orthogonal electromagnetic field region 23 and the secondary electron detector (1) 13 closer to the electron source than the electrode (1), the secondary electrons (SE) generated from the sample and the BSE_L The secondary electrons generated by the collision are deflected to the detector side and detected with high efficiency.

A positive voltage is applied to the electrode (1) 30 so that the signal detected by the detector (1) is only secondary electrons (SE). At this time, as shown in FIG.
Even if the reflected electrons collide with 0, the secondary electrons 36a generated therefrom are returned to the positive voltage of the electrode (1) and are not sent to the detector (1). On the other hand, the secondary electrons 12 directly generated from the sample are raised to the positive voltage of the electrode (1) and then deflected to the detector (1) by the orthogonal electromagnetic field generating means 23. Detected with high efficiency.

In order to increase the ratio of the backscattered electron (BSE_L) signal in the detection signal of the detector (1), a negative voltage is applied to the electrode (1). In this case, as shown in FIG. 4, the secondary electrons 12b having an energy lower than the voltage applied to the electrode (1) cannot pass through the electrode (1), and the secondary electrons 12b having an energy higher than the voltage of the electrode (1). Since only the electron 12a is detected by the detector (1), the amount of the secondary electron (SE) signal detected by the detector (1) decreases. On the other hand, the secondary electrons 36a generated from the electrode (1) 30 due to the collision of the reflected electrons (BSE_L) are accelerated by the negative voltage of the electrode (1),
Thereafter, the light is deflected to the detector side by the orthogonal electromagnetic field generation means 23 and detected. Therefore, the signal detected by the detector (1) is expressed as Ka × (SE) + Kb × (BSE_L) Expression (1). Here, Ka can be set to an arbitrary value of 1 or less by controlling the negative voltage of the electrode (1). Further, kb can be calculated by applying a positive voltage to the electrode (1).
0, and Kb = 1 if a negative voltage is applied to the electrode (1).
Becomes

The electrode (2) 32 shown in FIG. 1 is arranged closer to the electron source than the deflection coil. Therefore, reflected electrons (BSE_H) having a small cone angle can be converted into secondary electrons without blocking the scanning region of the primary electron beam 5 on the sample. Secondary electrons 36 generated at electrode (2)
b is detected by the detector (2), and its signal is BSE_H
Bring the information. Therefore, the detection signals of the detector (1) 13 and the detector (2) 34 are different from each other (Ks
e1, Kse2), the combined signal is Kse1 × (Ka × (SE) + Kb × (BSE_L)) + Kse2 × (BSE_H) = (Kse1 · Ka) × (SE) + (Kse1 · Kb) × (BSE_L) + Kse2 × (BSE_H) Equation (2) In the above equation, Kse1 and Kse2 are detectors.
By controlling the applied voltage of the photomultiplier of (1) and the detector (2), the value can be arbitrarily set. The value of Ka can be set to an arbitrary value of 1 or less by applying an arbitrary negative voltage to the electrode (1). Further, by switching the voltage of the electrode (1) 30 between positive and negative values by the voltage control power supply 31 and applying the voltage, the value of Kb can be set to 0 or 1. in this way,
By independently setting the applied voltage of the electrode (1) for controlling the detection amount of the secondary electrons 12 and the voltage of the photomultiplier of the detector (1) and the detector (2), SE information, BS
E_L information and BSE_H information are added and synthesized at an arbitrary ratio. Further, in the present configuration, it is possible to maintain the above signal relationship in a situation where a retarding voltage (negative voltage) is not applied to the sample.

Next, SE information, BSE_L information, BSE
FIGS. 5 to 11 show the characteristic means of the present invention for setting a composite signal with different _H information ratios with good operability.
This will be described with reference to FIG. In the present invention, the voltage applied to the photomultiplier of two signal detectors (corresponding to the gain of signal amplification)
, The following control means is provided. That is, when the voltages of the photomultipliers of the two signal detectors are VH1 and VH2, respectively, (VH1) × (VH1) + (VH2) × (VH2) = (constant) This is a mode in which VH1 and VH2 are controlled so as to satisfy the relationship of 3). By controlling VH1 and VH2 in this mode, the operating point A of VH1 and VH2 shown in FIG. 5 moves on the arc B, and the ratio between Kse1 and Kse2 can be changed smoothly. As shown in FIG. 6, the second control means is a mode for controlling VH1 and VH2 such that HV1 / VH2 = (constant) Equation (4) is satisfied. With this control means, the level of the composite signal can be changed while the ratio between Kse1 and Kse2 is kept substantially constant. At this time, the operating point A is a straight line B in FIG.
Move up. In the first control mode, (VH1) + (VH2) = (constant) The control method of Expression (5) can be used instead of Expression (3), as shown in FIG. Further, in the present invention, instead of the above-mentioned control means for directly controlling the voltage condition of the photomultiplier voltage, Kse1 corresponding to the signal level is used.
And Kse2. That is,
The relative relationship between the signal intensity of the signal detector shown in FIG. 8 and the applied voltage of the photomultiplier is stored in advance in the form of a control table or an approximate expression, and the voltage of the photomultiplier is controlled based on this relationship. The method (FIGS. 9 to 1)
1). By this method, the signal strength (SH
(1, SH2), (SH1) × (SH1) + (SH2) × (SH2) = (constant) Equation (5) or SH1 + SH2 = (constant) Equation (6) , SH1 / SH2 = (constant) The second control mode expressed by the following equation (7) becomes possible.

According to this method, the operation of changing the ratio between Kse1 and Kse2 while maintaining the state where the final signal level is kept constant, and the operation of maintaining the state where the ratio between Kse1 and Kse2 is kept constant, and The operation of changing the level can be performed independently.

[0021]

Embodiments of the present invention will be described below. FIG. 1 is a schematic diagram of an embodiment of the present invention. Electron source 1
A high-voltage control power supply 14
As a result, the extraction voltage is applied, and the primary electron beam 5 is emitted from the cathode 2. This primary electron beam 5 is accelerated by the high-voltage control power supply 14 by the voltage applied between the cathode 2 and the second anode 4, and proceeds to the subsequent lens system. After that, the primary electron beam 5 is converged by a first converging lens 6 (C1 lens) whose crossover position is controlled by a C1 lens control power supply 15 and passes through an objective lens aperture 7 to make unnecessary beams. The area is removed. The primary electron beam 5 that has passed through the objective lens aperture 7 is
After being converged by the second converging lens 8 (C2 lens) whose crossover position is controlled by the C2 lens control power supply 16, it is converged on the sample 11 by the objective lens 10. The objective lens 10 is controlled by an objective lens control power supply 19 so that the primary electron beam 5 is focused on the sample. A two-stage deflector 9 (9a, 9b) is arranged between the C2 lens 8 and the objective lens 10, and the primary electron beam 5 is two-dimensionally scanned on the sample 11 by the scanning power supply 17. You.

The secondary electrons 12 of low energy generated from the sample 11 are lifted to the electron source side by the magnetic field of the objective lens 10 and are sent to the secondary electron detector side by the orthogonal electromagnetic field generator 23 arranged above the objective lens. Be deflected. In the orthogonal electromagnetic field generator 23, a field in which the optical axis and the electric and magnetic fields are orthogonal to each other is created, and the intensity thereof is higher than that of the primary electron beam 5 without giving a deflecting effect to the primary electron beam 5. The CPU 20 is controlled to deflect the signal electrons in the direction of the detector (1) 13 for the signal electrons having low energy. The detector (1) 13 has about 10 kV
And a photomultiplier that converts the light emitted from the scintillator into an electric signal. The photomultiplier voltage of the detector (1) 13 is controlled by a photomultiplier control power supply 18.

An axially symmetric electrode (2) 32 is disposed closer to the electron source than the deflectors 9a and 9b, and when a reflected electron (BSE_H) 24b having a small cone angle collides with the electrode (2), a secondary electron is emitted. 36b occurs. A detector (2) 34 is arranged at a position where the secondary electrons can be detected. Similarly to the detector (1), the detector (2) is composed of a scintillator having a surface applied with a high voltage of about 10 kV and a photomultiplier for converting the light emitted from the scintillator into an electric signal. The photomultiplier voltage of the detector (2) 34 is controlled by a photomultiplier control power supply 35.

The signal outputs of the detector (1) 13 and the detector (2) 34 are added by a signal adder 38 and then added to the CPU 20.
Is read into the image memory 22 and simultaneously displayed on the image display means 21 as a sample image.

The objective lens 10 and the orthogonal electromagnetic field generating means 23
Between them, an axially symmetric electrode (1) 30 is disposed, and a control power supply 31 applies a positive voltage and a negative variable voltage. When a positive voltage is applied to the electrode (1) 30, the sample 11
The secondary electrons 12 directly generated from are raised to the voltage of the electrode (1) and then deflected by the orthogonal electromagnetic field generation means 23 to the detector (1) 13 side to be detected. On the other hand, of the reflected electrons generated from the sample, a component (BSE_L) 24a having a large cone angle collides with the electrode (1) 30 and secondary electrons 36a having information of BSE_L from the electrode (1).
, But is pulled back by the positive voltage applied to the electrode (1) and is not detected by the detector (1) (FIG. 3).
reference). When a negative voltage is applied to the electrode (1) 30 by an operation of the operator, a part 12b (see FIG. 4) of the secondary electrons generated from the sample is changed by the negative voltage of the electrode (1) 30. Is not detected because it cannot pass through
The _L signal 24a is converted into secondary electrons 36a by the electrode (1), accelerated by the negative voltage of the electrode (1) 30, deflected by the orthogonal electromagnetic field generating means 23, and detected by the detector (1) 13. Is done. As a result, the signal output SH1 of the detector (1)
SH1 = Kse1 × (Ka × (SE) + Kb × (BSE
_L)). Here, Ka and Kb are controlled by the voltage applied to the electrode (1), and Kse1 is controlled by the photovoltage (VH1) of the detector (1).

On the other hand, the reflected electrons (BSE_H) 24b generated from the sample 11 and having a small cone angle are converged by the objective lens 10 and then pass through the orthogonal electromagnetic field generating means 23 and collide with the electrode (2) 32. BSE_ from electrode (2)
The secondary electrons 36b having H information are generated. Since the secondary electrons 36b are detected by the detector (2) 34,
The signal output SH2 of the detector (2) 34 is controlled as follows: SH2 = Kse2 × (BSE_H). Here, Kse2 is controlled by the photovoltage (VH2) of the detector (2). These SH1,
The signal of SH2 is added by the signal adding means 38, and CP
Read by U20. Therefore, the signal read by the CPU 20 is SH1 + SH2 = (Kse1 × Ka) × (SE) + (K
se1 × Kb) × (BSE_L) + Kse2 × (BSE
_H).

In the present embodiment, the photovoltaic voltages (VH1, VH2) of the detector (1) and the detector (2) are controlled independently of each other. Do not change the level much,
A first control mode for changing only the ratio of se1 and Kse2, and a second control mode for changing the level of the entire addition signal while keeping the ratio of Kse1 and Kse2 constant.
The control mode can be selected and operated.

As embodiments of the first control mode, the following four methods are possible. (1) (VH1) × (VH1) + (VH2) × (VH
2) = Control that satisfies the condition of (constant) (2) (VH1) + (VH2) = Control that satisfies the condition of (constant) (3) (SH1) × (SH1) + (SH2) × (SH
2) Control that satisfies the condition of (constant) (4) Control that satisfies the condition of (SH1) + (SH2) = (constant) Note that, of the above-described embodiments, examples (3) and (4) Are stored in advance in the internal storage device of the control CPU 20 with the photovoltages (VH1, VH2) and the signal outputs (SH1, SH2).
Is stored as a numerical table or an approximate function.

As embodiments of the second control mode, the following two methods are possible. (1) Control satisfying the condition of (VH1) / (VH1) = (constant) (2) Control satisfying the condition of (SH1) / (SH2) = (constant) FIG. This is an example in which it is also arranged between the orthogonal electromagnetic field generating means 23 and the deflector. in this case,
A reflected electron component that does not collide with either the electrode (1) 30 or the electrode (2) 32 is converted by the electrode (3) 33 into secondary electrons 36c.
In this configuration example, it is possible to detect the reflected electrons while suppressing the detection loss.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of the present invention when applied to an in-lens type scanning electron microscope.

FIG. 2 is a schematic diagram of a trajectory of a backscattered electron having different angles generated from a sample.

FIG. 3 is a schematic diagram of detection control means for suppressing backscattered electrons (BSL_L) and detecting only secondary electrons (SE).

FIG. 4 suppresses secondary electrons (SE) and reflects reflected electrons (BSL).
_L) is a schematic diagram of detection control means for detecting only or at an arbitrary ratio.

FIG. 5 is a schematic diagram of control means for controlling a signal ratio of two detectors by photomultiplier voltages (VH1, VH2), and shows a relationship between photomultiplier voltages by (VH1).
× (VH1) + (VH2) × (VH2) = (constant).

FIG. 6 is a schematic diagram of control means for controlling a signal ratio of two detectors by photomultiplier voltages (VH1, VH2), and shows a relationship between photomultiplier voltages (VH1);
/ (VH2) = (constant).

FIG. 7 is a schematic diagram of control means for controlling a signal ratio of two detectors by photomultiplier voltages (VH1, VH2), and shows a relationship between photomultiplier voltages (VH1);
+ (VH2) = (constant).

FIG. 8 shows a photomultiplier voltage (VH1, VH) of the detector.
H2) and a schematic diagram of a relationship between detection intensities (SH1, SH2) of the detector.

FIG. 9 shows the signal ratio of the two detectors as the detection intensity (SH
1, SH2), and shows the relationship between the detected intensities as (SH1) × (SH1) + (SH2).
× (SH2) = (constant).

FIG. 10 shows the signal ratio of the two detectors as the detection intensity (SH
1, SH2), where the relationship between the detected intensities is (SH1) / (SH2) = (constant).

FIG. 11 shows the signal ratio of the two detectors as the detection intensity (SH
1, SH2), where the relationship between the detected intensities is (SH1) + (SH2) = (constant).

FIG. 12 is a case where an axis symmetric electrode is added to the example of FIG. 1;

FIG. 13 is an observation image at an accelerating voltage of 2 kV using a catalyst containing platinum particles inside carbon as a sample, showing differences in sample information depending on detection signals.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electron source, 2 ... Cathode, 3 ... First anode, 4 ... Second anode,
5: primary electron beam, 6: C1 lens, 7: objective lens aperture, 8: C2 lens, 9a, 9b: deflection coil, 10
... Objective lens, 10a ... Objective lens magnetic field, 11 ... Sample,
12 ... secondary electrons, 13 ... detector (1), 14 ... high voltage control power supply, 15 ... C1 lens control power supply, 16 ... C2 lens control power supply, 17 ... scanning power supply, 18 ... photo voltage control power supply (1), 19: Objective lens control power supply, 20: CPU, 2
DESCRIPTION OF SYMBOLS 1 ... Image display apparatus, 22 ... Image memory, 23 ... Orthogonal electromagnetic field generator, 24 ... Backscattered electrons (a ... BSE_L, b ... BSE)
_H), 30: axially symmetric electrode (1), 31: electrode voltage control power supply, 32: electrode (2), 34: detector (2), 35 ...
Photovoltaic voltage control power supply (2), 36 ... Secondary electrons generated by collision of reflected electrons (a, b, c ... Secondary electrons generated by collision of reflected electrons having different cone angles), 38 ... Signal adder.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Todokoro 882-mo, Oji-shi, Hitachinaka-shi, Ibaraki Pref. Within the Measuring Instruments Group of Hitachi, Ltd. F-term in the Hitachi Measuring Instruments Group (reference) 2G001 AA03 BA07 BA14 CA03 DA01 GA01 GA06 GA09 GA10 GA13 HA01 HA12 HA13 JA03 JA13 5C033 NN01 NN02 NP01 NP04 NP06 UU02 UU04 UU05

Claims (15)

[Claims] 1. A beam converging means for narrowing down a primary electron beam emitted from an electron source with an objective lens, a beam scanning means for scanning the primary electrons on a sample, and a secondary signal generated from the sample by the beam scanning. Has an image display means for displaying an enlarged image of the sample, the electron source side than the objective lens,
A plurality of signal conversion means for separately converting signal electrons (BSE_L, BSE_H) having high energy and different emission angle ranges from the sample from the secondary signals generated from the sample into signal electrons having low energy, respectively. And secondary signal electrons (S
E) and a plurality of signal detection means for detecting the signal electrons converted by the plurality of signal conversion means, and, among the signal electrons detected by the signal detection means, signal electrons having low energy directly generated from the sample ( SE), comprising: a signal control means for controlling the detection amount of SE); and a signal addition means for adding the signals of the plurality of signal detection means, wherein the signal addition means adjusts the signal level of each addition signal. An addition ratio control means which is set independently is provided, and a combined operation of the addition ratio control means and the signal control means causes a low-energy secondary signal (SE) generated from the sample and a high energy having a different emission angle from the sample. Energy secondary signal (BSE_L, BS
E_H) and variable ratios (K1, K2,
An electron beam apparatus for generating a sample signal added in K3): K1 × SE + K2 × BSE_L + K3 × BSE_H. 2. The electron beam apparatus according to claim 1, wherein the low-energy secondary signal electrons directly generated from the sample are detected by a detection means closest to an objective lens among the plurality of signal detection means. An electron beam apparatus characterized in that: 3. The electron beam apparatus according to claim 1, wherein the plurality of signal conversion units are disposed on the electron beam side and the objective lens side with respect to the beam scanning unit. An electron beam apparatus characterized by the above-mentioned. 4. An electron beam apparatus according to claim 1, further comprising: an orthogonal electromagnetic field generating means in which an electric field and a magnetic field are formed orthogonal to each other between said beam scanning means and an objective lens magnetic field. An electron beam apparatus, wherein the plurality of signal conversion means are arranged closer to the objective lens than the orthogonal electromagnetic field generating means and closer to the electron source than the beam scanning means. 5. The electron beam apparatus according to claim 1, further comprising: an orthogonal electromagnetic field generating means in which an electric field and a magnetic field are formed orthogonal to each other between said beam scanning means and an objective lens magnetic field. An electron beam apparatus, wherein the plurality of signal conversion units are arranged between the orthogonal electromagnetic field generation unit and the scanning unit, and closer to the electron source than the beam scanning unit. 6. An electron beam apparatus according to claim 1, further comprising: an orthogonal electromagnetic field generating means in which an electric field and a magnetic field are formed orthogonal to each other between said beam scanning means and an objective lens magnetic field. The plurality of signal converting means are disposed between the orthogonal electromagnetic field generating means and the scanning means, between the orthogonal electromagnetic field generating means and the objective lens magnetic field, and closer to the electron source than the beam scanning means. An electron beam device characterized by being arranged. 7. An electron beam apparatus according to claim 1, wherein an axially symmetric electrode surrounding an optical axis is provided between said objective lens and a secondary signal detecting means closest to said objective lens. An electron beam apparatus comprising: voltage applying means for applying positive and negative voltages to the electrodes; and controlling a detection amount of the low energy secondary signal by controlling the voltage applying means. 8. An electron beam apparatus according to claim 7, wherein said axially symmetric electrode is used as signal conversion means for converting a high-energy secondary signal into a low-energy secondary signal. Line equipment. 9. The electron beam apparatus according to claim 4, wherein the electric field and the magnetic field generated by said orthogonal electromagnetic field generating means are arranged so as not to have a deflecting effect on the primary electron beam. An electron beam apparatus, the intensity of which is set. 10. The electron beam apparatus according to claim 1, wherein the observation sample is arranged in a magnetic field of an objective lens. 11. The electron beam apparatus according to claim 10, wherein the objective lens has a structure in which a sample is arranged between magnetic poles of the objective lens. 12. An electron beam apparatus according to claim 1, wherein said signal detecting means comprises a scintillator and a photomultiplier arranged at two positions, and each of said signal detecting means applies an applied voltage to said photomultiplier. Assuming that VH1 and VH2, (VH1) × (VH1) + (VH2) × (VH2) =
A first control mode for controlling each photomultiplier voltage (VH1, VH2) while maintaining a relationship of (constant), and a photomultiplier for each photomultiplier maintaining the relationship of VH1 / VH2 = (constant) A second control mode for controlling the voltages (VH1, VH2). 13. An electron beam apparatus according to claim 1, wherein said signal detecting means comprises a scintillator and a photomultiplier arranged at two places, and each of said signal detecting means applies an applied voltage to said photomultiplier. When VH1 and VH2 are set, a first control mode for controlling each of the photomultiplier voltages (VH1 and VH2) while maintaining a relationship of (VH1) + (VH2) = (constant), and VH1 / VH2 = A second control mode for controlling each of the photomultiplier voltages (VH1, VH2) while maintaining the relationship (constant). 14. An electron beam apparatus according to claim 1, wherein said signal detecting means comprises a scintillator and a photomultiplier arranged at two positions, and respectively applies an applied voltage to said photomultiplier. When VH1 and VH2 are set, a means for storing a relative relationship between the applied voltage (VH1 and VH2) of the photomultiplier and the signal output (SH1 and SH2) is provided, and (VH1) stored in the storage means is stored. , VH
Based on the relative relationship between (2) and (SH1, SH2), the signal output (SH1, SH2) is (SH1) × (SH1) + (SH2) × (SH2) =
A first control mode for controlling each photomultiplier voltage (VH1, VH2) while maintaining a relationship of (constant); and a photomultiplier for each photomultiplier maintaining a relationship of SH1 / SH2 = (constant). A second control mode for controlling the voltages (VH1, VH2). 15. An electron beam apparatus according to claim 1, wherein said signal detecting means comprises a scintillator and a photomultiplier arranged at two places, and each of said signal detecting means detects a voltage applied to said photomultiplier. When VH1 and VH2 are set, a means for storing a relative relationship between the applied voltage (VH1 and VH2) of the photomultiplier and the signal output (SH1 and SH2) is provided, and (VH1) stored in the storage means is stored. , VH
Based on the relative relationship between (2) and (SH1, SH2), the respective photomultiplier voltages (VH1, VH2) are maintained while maintaining the relationship that the signal outputs (SH1, SH2) are (SH1) + SH2 = (constant). A first control mode for controlling, and a second control mode for controlling each photomultiplier voltage (VH1, VH2) while maintaining a relationship of SH1 / SH2 = (constant). Electron beam device.