JP2010112944A - Surface analyzer and analysis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface analyzer and an analysis method capable of analyzing a magnetization distribution on the sample surface with high accuracy. <P>SOLUTION: Secondary electrons emitted from the sample 2 and scattered by colliding with a target 3 are detected by electron detectors 4-1 to 4-4 arranged on a plurality of measuring positions. Each electron detector 4-1 to 4-4 is rotated by a rotation part 5 by using a vertical direction to the sample surface as a rotation axis, and moved to the next measuring position to repeat detection processing of the secondary electrons, and an operation processing part 7 calculates a spin component of the secondary electrons based on an addition value of each detected value by the electron detectors 4-1 to 4-4 on each measuring position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface analysis apparatus and an analysis method.

  A spin polarization SEM that combines an electron spin analyzer that measures secondary electron polarization (spin bias) and a scanning electron microscope (SEM) is known as an analyzer that analyzes the magnetization vector of the surface of a magnetic material. It has been.

  In spin-polarized SEM, a sample surface is irradiated with a primary electron beam, and secondary electrons having magnetization information are emitted. Then, the emitted secondary electrons collide with a metal target (target) and detected by a plurality of electron detectors arranged around the target. Here, the direction of the magnetic vector on the sample surface can be known from the counting difference of the secondary electrons detected by the electron detectors arranged in each direction.

  In addition, since the charge of one electron is extremely small, in general, an electron detector corresponds to one incident electron by multiplying the incident electron by using an electron multiplier such as a channeltron. It is detected as the amount of multiplied electrons.

  In recent years, for example, in magnetic recording, the density has increased, and the magnetic head size and recording pattern have also been miniaturized. For this reason, the demand of the analysis technique which can analyze the sample which has a fine magnetic domain structure with high resolution is increasing. A spin-polarized SEM can observe a magnetic domain image with an excellent resolution of an electron microscope. In addition, it has analytical capabilities that are not available in magnetic force microscopes, such as direct measurement of the magnetization vector direction. Conventionally, spin-polarized SEM has been mainly used as an apparatus for basic physics research, but has recently begun to be used for industrial purposes such as development of high-density magnetic recording technology.

JP 60-177539 A JP 11-111209 A

Hayakawa, Koike, Matsuyama, "Spin Polarized Scanning Electron Microscope", Electron Microscope vol.22, No.3, 1988

  However, since the electron detector of the spin-polarized SEM has low detection efficiency, it is necessary to obtain a count value corresponding to the number of incident electrons as accurately as possible, but it is difficult to obtain an accurate count value with the electron detector, It was difficult to improve analysis accuracy.

  In view of the above points, an object of the present invention is to provide a surface analysis apparatus and an analysis method capable of analyzing a magnetization distribution on a sample surface with high accuracy.

  In order to achieve the above object, a surface analysis apparatus having the following configuration is provided. The surface analysis apparatus includes a metal target for colliding and scattering secondary electrons emitted from a sample, a plurality of electron detectors for detecting the scattered secondary electrons, and a direction perpendicular to the sample surface. And a rotation unit that rotates each of the electron detectors and moves them to a plurality of measurement positions, and the addition value of the detection values of the plurality of electron detectors at each of the measurement positions. An arithmetic processing unit that calculates a spin component of secondary electrons.

  Moreover, in order to achieve the said objective, the surface analyzer which has the following structures is provided. The surface analyzer is configured to pulse the secondary electron emitted from the sample by applying a pulse voltage to a metal target for colliding and scattering secondary electrons emitted from the sample, A lead-in electrode that pulls in the direction of the metal target; a pulse voltage supply that applies the pulse voltage to the lead-in electrode; a plurality of electron detectors that detect the secondary electrons scattered and pulsed by the metal target; Have.

  According to the disclosed surface analysis apparatus and analysis method, the magnetization distribution on the sample surface can be analyzed with high accuracy.

It is a figure which shows schematic structure of the principal part of the surface analyzer of 1st Embodiment. It is a figure which shows the structural example of an electron detector and a signal processing part. It is the top view which showed typically arrangement | positioning of four electron detectors. It is a figure which shows the structure of an example of the surface analyzer of 1st Embodiment. It is a flowchart which shows the analysis method using a pixel addition system. It is a flowchart which shows the flow of a detection process of a secondary electron. It is a flowchart which shows the analysis method using a surface addition system. It is a flowchart which shows the other example of the analysis method. It is a figure which shows the mode of detection of incident electrons. It is a figure which shows schematic structure of the principal part of the surface analyzer of 2nd Embodiment. It is a figure which shows the difference of the secondary electron drawn by the difference of the voltage applied to a drawing electrode. It is a figure which shows the modification of the pulse voltage applied to a drawing-in electrode. It is a figure which shows the structure of an example of the surface analyzer of 2nd Embodiment. It is a figure which shows a mode that a secondary electron pulse is scanned in one dimension. It is a figure which shows a mode that a secondary electron pulse is scanned in two dimensions. It is a figure which shows an example of a multichannel electron detector.

Embodiments of a surface analysis apparatus and an analysis method of the present invention will be described below with reference to the drawings.
Examples of the reasons why it is difficult to obtain an accurate count value of incident electrons with the electron detector of the surface analyzer include the following.

  The first cause is that the count values in a plurality of electron detectors arranged around the target vary due to a shift in multiplication factor of the electron multiplier. As a result, the offset component due to the above-described variation is also superimposed on the secondary electron count difference between the electron detectors arranged in each direction, resulting in a decrease in analysis accuracy.

  The second cause is that when the interval at which a plurality of electrons are incident on the electron detector is short, for example, when two electrons are incident on the electron detector at the same time, the count value of the electron detector is counted as 1. (Details will be described later).

In the following, a surface analysis apparatus and an analysis method for preventing a decrease in analysis accuracy due to the first cause will be described first.
(First embodiment)
FIG. 1 is a diagram illustrating a schematic configuration of a main part of the surface analysis apparatus according to the first embodiment.

  The surface analyzer 1 includes a target 3 that collides with secondary electrons emitted from the surface of the sample 2 by the irradiated primary electron beam, and an electron detector 4-1 that detects secondary electrons scattered by the target 3. , 4-2, 4-3, 4-4. Furthermore, the surface analysis apparatus 1 includes a rotating unit 5 that rotates the electron detectors 4-1 to 4-4, a signal processing unit 6, and an arithmetic processing unit 7.

  For the target 3, for example, a heavy metal such as Au (gold) or U (uranium) is used. In addition, a voltage of about 20 kV to 120 kV, for example, is applied to the target 3 in order to accelerate and collide secondary electrons.

  The electron detectors 4-1 to 4-4 detect four secondary electrons scattered at a certain interval around the target 3 in order to detect the secondary electrons scattered at an angle corresponding to the spin-orbit interaction by the spin component. Has been placed.

  The rotating unit 5 is, for example, a motor that can rotate ± 360 ° or ± 180 °, and rotates the electron detectors 4-1 to 4-4 with the direction perpendicular to the sample surface as a rotation axis. For example, when an XYZ coordinate system as shown in FIG. 1 is set, the Z axis is set as the rotation axis.

FIG. 2 is a diagram illustrating a configuration example of the electron detector and the signal processing unit.
The electron detectors 4-1 to 4-4 in FIG. 1 are, for example, channeltron electron multipliers 4a.

The signal processing unit 6 includes a preamplifier 6a, a discriminator (wave height discriminator) 6b, and a counter 6c.
Since the incident charge of one secondary electron 8 is extremely small, it is multiplied by the channeltron electron multiplier 4a and the preamplifier 6a, and when the charge amount exceeds a certain amount, one secondary electron 8 is The discriminator 6b is assumed to be incident and outputs one pulse.

The counter 6c counts the number of pulses output from the discriminator 6b, and outputs the counted value as the number of electrons incident on the channeltron electron multiplier 4a.
As the electron detectors 4-1 to 4-4, MCP (Micro-Channel Plate) which is a kind of electron multiplier may be used.

The arithmetic processing unit 7 in FIG. 1 calculates the spin component of secondary electrons from the detection values of the electron detectors 4-1 to 4-4 output from the signal processing unit 6.
Next, the operation of the surface analysis apparatus 1 shown in FIG. 1 will be described.

First, a case where the electron detectors 4-1 to 4-4 are not rotated will be described as a comparative example.
FIG. 3 is a top view schematically showing the arrangement of four electron detectors.
In order to detect the x component of the spin of secondary electrons in the XY coordinates centered on the position of the target 3, an electron detector 4-1 is detected at the X + position on the X axis, and an electron is detected at the X− position. A device 4-3 is arranged. Further, in order to detect the y component of the spin, the electron detector 4-2 is disposed at the Y + position on the Y axis, and the electron detector 4-4 is disposed at the Y− position.

When the detection values (number of electrons) detected by the electron detectors 4-1 to 4-4 are SD1 to SD4, the spin x component Sx and the spin y component Sy are obtained by the arithmetic processing unit 7 as follows. It is done.
Sx = (SD1-SD3) (1)
Sy = (SD2-SD4) (2)
The spin x component Sx and the y component Sy correspond to the x component and the y component of the magnetic vector at the irradiation position of the primary electron beam of the sample 2, and by obtaining Sx and Sy, the magnetization of the surface of the sample 2 is obtained. Distribution can be analyzed.

However, if there is a shift in the multiplication factor of the electron detectors 4-1 to 4-4, a correct spin component cannot be obtained.
In order to prevent this, in the surface analyzer 1 of the present embodiment, the rotating unit 5 rotates the electron detectors 4-1 to 4-4 with the direction perpendicular to the sample surface as the rotation axis, and a plurality of the detectors 4-4. Move to measurement position.

  For example, in the arrangement of the electron detectors 4-1 to 4-4 shown in FIG. 3, the rotating unit 5 moves the electron detector 4-1 from the position of X + to Y +, X−, Y−. The secondary electrons are detected at each measurement position. The electron detectors 4-1 to 4-4 are connected to, for example, a common member, and move to four measurement positions (X +, X-, Y +, Y-) in conjunction with each other, and four measurements are performed. Detection is performed simultaneously at the position.

The added values of the detection results of the electron detectors 4-1 to 4-4 at each measurement position are (SD1 + SD2 + SD3 + SD4) _X +, (SD1 + SD2 + SD3 + SD4) _X−, (SD1 + SD2 + SD3 + SD4) _Y +, (SD1 + SD2 + SD3 + SD4) _Y−. At this time, the spin component is obtained by the arithmetic processing unit 7 as follows.
Sx = {(SD1 + SD2 + SD3 + SD4) _X +} − {(SD1 + SD2 + SD3 + SD4) _X−} (3)
Sy = {(SD1 + SD2 + SD3 + SD4) _Y +} − {(SD1 + SD2 + SD3 + SD4) _Y−} (4)
As described above, in the surface analysis apparatus 1 of the present embodiment, the spin component is obtained using the sum of the detected values of the secondary electrons detected by using the electron detectors 4-1 to 4-4 at each measurement position. Therefore, the influence of variation in multiplication factor among the electron detectors 4-1 to 4-4 can be reduced. This makes it possible to analyze the magnetization distribution on the sample surface with high accuracy.

Hereinafter, an example of the entire configuration of the surface analysis apparatus including the main part illustrated in FIG. 1 will be described.
FIG. 4 is a diagram illustrating a configuration of an example of the surface analysis apparatus according to the first embodiment.
The surface analyzer 10 includes a vacuum chamber 11, and the electron spin analyzer 12 including the plurality of electron detectors 4-1 to 4-4 and the target 3 described above, and a sample stage 13 are placed in the vacuum chamber 11. is set up. An SEM column 14 for irradiating the sample surface with a primary electron beam and emitting secondary electrons having magnetization information on the sample surface is also introduced into the vacuum chamber 11.

  Outside the vacuum chamber 11, a rotation mechanism 15, a rotation mechanism control circuit 16, a detector control circuit 17, a detection signal processing circuit 18, a sample stage control circuit 19, a beam scanning system control circuit 20, and an electron optical system control circuit 21 are provided. It is done. Further, a control computer 22 and a display device 23 connected to the control computer 22 are provided.

  The rotation mechanism 15 is, for example, a motor, and rotates the electron detectors 4-1 to 4-4 of the electron spin analyzer 12 connected to the drive shaft thereof by feedthrough or the like. Note that the rotation mechanism 15 may be provided in the vacuum chamber 11. As the rotating mechanism 15, for example, a mechanism capable of rotating ± 360 ° or ± 180 ° is used.

The rotation mechanism control circuit 16 controls the rotation mechanism 15. For example, the electron detectors 4-1 to 4-4 are rotated and controlled to stop at the measurement position as shown in FIG.
The detector control circuit 17 controls the electron spin analyzer 12. For example, the voltage applied to the target 3 shown in FIG. 1 is controlled. Moreover, in the electron detectors 4-1 to 4-4, in order to multiply the secondary electrons, for example, a gain is adjusted using a high-precision high-voltage power supply.

  The detection signal processing circuit 18 corresponds to the signal processing unit 6 shown in FIGS. 1 and 2 and includes a preamplifier 6a, a discriminator 6b, and a counter 6c, and an electronic detector 4-1 at each measurement position. Process the detection signals (X +, X−, Y +, Y− detection signals) from ˜4-4. Note that the detection signal processing circuit 18 can adjust the gain by changing the threshold of the amount of charge required for generating a pulse corresponding to one electron in the discriminator 6b. . In that case, the detector control circuit 17 does not need to adjust the gain by the high-precision high-voltage power supply.

The sample stage control circuit 19 controls the position of the sample stage 13 in the vacuum chamber 11.
The beam scanning system control circuit 20 controls the SEM column 14 to determine the irradiation position of the primary electron beam on the sample surface.

The electron optical system control circuit 21 adjusts an acceleration voltage, an electron beam current, and the like of the primary electron beam irradiated on the sample from the SEM column 14.
The control computer 22 is, for example, a computer. While controlling each control circuit, for example, it has the function of the arithmetic processing unit 7 shown in FIG. 1 and calculates a spin component based on the detection signal processed by the detection signal processing circuit 18.

The display device 23 displays the analysis result of the spin component in the control computer 22 and the like.
In addition to the above configuration, the surface analyzer 10 may be provided with a measuring head for measuring the degree of vacuum, but the illustration is omitted.

Hereinafter, the operation (analysis method) of the surface analysis apparatus 10 shown in FIG. 4 will be described.
FIG. 5 is a flowchart showing an analysis method using the pixel addition method.
The analysis method using the pixel addition method is a method of obtaining the amount of secondary electrons necessary for analysis for each irradiation position of the primary electron beam on the sample surface.

  First, initial setting is performed (step S1). Here, under the control of the control computer 22, the detector control circuit 17 sets a voltage to be applied to the electron spin analyzer 12. The beam scanning system control circuit 20 and the electron optical system control circuit 21 set a scanning range of the primary electron beam to be irradiated, an acceleration voltage, an electron beam current, and the like. Further, the inside of the vacuum chamber 11 is exhausted by a vacuum pump (not shown).

  Next, under the control of the control computer 22, the beam scanning system control circuit 20 determines the Y coordinate of the irradiation position of the primary electron beam by the SEM column 14 (step S2). The coordinate system is set, for example, as shown in FIG. 1, and the irradiation position of the primary electron beam on the sample surface is indicated by XY coordinates.

  Next, under the control of the control computer 22, the beam scanning system control circuit 20 determines the X coordinate of the irradiation position of the primary electron beam by the SEM column 14 (step S3). This determines the irradiation position of the primary electron beam.

  When the irradiation position of the primary electron beam is determined and the sample is irradiated with the primary electron beam from the SEM column 14, secondary electrons are emitted from the surface of the sample, and secondary electron detection processing using the electron spin analyzer 12 is performed. Is started (step S4). For example, the detection result is transmitted to the control computer 22 via the detection signal processing circuit 18 and stored in a storage unit such as a RAM (Random Access Memory) of the control computer 22. Details of the secondary electron detection process will be described later.

  The beam scanning system control circuit 20 determines whether or not the scanning of the irradiation position in the X direction has been completed (step S5), and if the scanning in the X direction has not been completed, the irradiation position of the primary electron beam Is updated (step S6). Thereafter, the processing from step S3 is repeated. When the scanning in the X direction is finished, the beam scanning system control circuit 20 determines whether or not the scanning in the Y direction is finished (step S7). Then, when the scanning in the Y direction is not completed, the beam scanning system control circuit 20 updates the Y coordinate of the irradiation position of the primary electron beam (step S8). Thereafter, the processing from step S2 is repeated.

  When the scanning in the Y direction is completed, the control computer 22 determines the electron detectors 4-1 to 4-4 at the four measurement positions described above for each irradiation position of the primary electron beam from the stored detection results of the secondary electrons. The addition value of the detection result of -4 is obtained. Then, from equations (3) and (4), the spin component of secondary electrons emitted from the irradiation position is calculated, and the magnetization vector of the sample surface uniquely determined from the spin component is analyzed (step S9). For example, the control computer 22 may display the magnetization vector at each irradiation position on the display device 23.

Next, the secondary electron detection process that is the process of step S4 will be described.
FIG. 6 is a flowchart showing the flow of secondary electron detection processing.
Under the control of the control computer 22, the rotation mechanism control circuit 16 rotates the rotation mechanism 15 to change the electron detectors 4-1 to 4-4 of the electron spin analyzer 12 as shown in FIG. Two measurement positions (X +, X-, Y +, Y-) are set (step S10).

  Next, the detection signal processing circuit 18 counts the number of electrons detected by the electron detectors 4-1 to 4-4 at the four measurement positions in a certain period (step S11). Specifically, the detection signal processing circuit 18 outputs the secondary electron detection results (X + detection signal, X− detection signal, Y + detection signal, Y− detection signal) in the electron detectors 4-1 to 4-4. Receive. Then, after each detection signal is amplified by the preamplifier 6a as shown in FIG. 2, the number of electrons (SD1 to SD1) considered to be input to each of the electron detectors 4-1 to 4-4 by the discriminator 6b and the counter 6c. SD4) is counted (step S11).

  If the measurement time for obtaining the number of electrons necessary for analysis is T at each irradiation position of the primary electron beam on the sample surface, the rotation mechanism 15 is based on the electron detectors 4-1 to 4-4. The electron detectors 4-1 to 4-4 are rotated so that one measurement time at each measurement position becomes T / 4. Thereby, it can measure in the time equivalent to the case where it fixes and detects the electron detectors 4-1 to 4-4, and can prevent the increase in the measurement time of a secondary electron.

  The measurement time T for obtaining the number of electrons necessary for the analysis is appropriately determined according to the magnetic sample to be inspected, the acceleration voltage of the primary electron beam to be irradiated, and the electron beam current. For example, when the acceleration voltage or electron beam current of the primary electron beam is large, more secondary electrons are emitted, and therefore the measurement time T can be shortened.

  Next, the rotation mechanism control circuit 16 determines whether or not each of the electron detectors 4-1 to 4-4 has completed detection at all measurement positions (step S12). 4-1 to 4-4 are rotated and moved to the next measurement position (step S13). Thereafter, the processing from step S10 is repeated.

When the detection at all measurement positions is completed, the detection process is terminated.
While the electron detectors 4-1 to 4-4 are rotated, the sample may continue to be irradiated with the primary electron beam, but the number of electrons is not counted. For example, counting by the counter 6c is stopped. Further, for example, the beam scanning system control circuit 20 may control the SEM column 14 to adjust the irradiation direction of the primary electron beam so that the sample is not irradiated.

Next, an analysis method using the surface addition method will be described.
FIG. 7 is a flowchart showing an analysis method using the surface addition method.
The surface addition method is a method of obtaining the amount of secondary electrons required for analysis by irradiating the same sample surface with a primary electron beam scanned a plurality of times.

  First, initial setting is performed (step S21). Here, under the control of the control computer 22, the detector control circuit 17 sets a voltage to be applied to the electron spin analyzer 12. The beam scanning system control circuit 20 and the electron optical system control circuit 21 set a scanning range of the primary electron beam to be irradiated, an acceleration voltage, an electron beam current, and the like. Further, the number of times of primary electron beam irradiation (number of times of surface addition) performed on the same sample surface for obtaining the amount of secondary electrons necessary for analysis is set.

The process of steps S22 to S28 is the same as the process of steps S2 to S8 of the analysis method shown in FIG.
If it is determined in step S27 that scanning in the Y direction has been completed, the beam scanning system control circuit 20 determines whether scanning for the set number of times of surface addition has been completed (step S29). If it is determined that the process has not been completed, the process from step S22 is repeated.

  When the scan of the number of surface additions is completed, the control computer 22 detects the electron detectors 4-1 to 4-4 at the four measurement positions described above for each irradiation position from the stored secondary electron detection result. Find the sum of the results. Then, the control computer 22 calculates the spin component of the secondary electrons emitted from the irradiation position from the equations (3) and (4), and analyzes the magnetization vector of the sample surface uniquely determined from the spin component (step). S30).

  Note that the secondary electron detection process in step S24 is the same as the flow shown in FIG. 6, but in the case of the surface addition method analysis method, the measurement is performed for each measurement position by the electron detectors 4-1 to 4-4. One measurement time is shorter than in the case of the pixel addition method as follows.

  Assuming that the total measurement time for obtaining the number of electrons necessary for the analysis at each irradiation position of the primary electron beam on the sample surface is T and the number of surface additions is n, the beam scanning system control circuit 20 The irradiation position is updated every n hours. In the analysis method of the present embodiment, the rotation mechanism 15 moves the electron detectors 4-1 to 4-4 to four measurement positions during the T / n time, so that each measurement position is measured. One measurement time at is T / (4n).

  According to the analysis method using such a surface addition method, secondary electrons can be measured in the same time as when the electron detectors 4-1 to 4-4 are fixed and detected. An increase in time can be prevented. In addition, since the irradiation position is scanned every T / n time, it is possible to prevent the irradiation of the primary electron beam for a long time to one irradiation position, and it is possible to suppress the change in the surface state.

Next, another example of the analysis method will be described.
FIG. 8 is a flowchart showing another example of the analysis method.
The analysis method shown in FIG. 8 measures the secondary electrons by irradiating the scanning range of the sample surface with the primary electron beam while fixing the measurement positions of the electron detectors 4-1 to 4-4. When completed, the electron detectors 4-1 to 4-4 are rotated to repeat the measurement of secondary electrons.

The process of steps S31 to S33 is the same as the process of steps S1 to S3 of the analysis method shown in FIG.
When the irradiation position of the primary electron beam is determined in the process of step S33 and the sample is irradiated with the primary electron beam from the SEM column 14, the electron detectors 4-1 to 4-4 fixed at the respective measurement positions are detected. The secondary electrons emitted from the sample surface and scattered by the target 3 are detected. Then, the detection signal processing circuit 18 counts the number of secondary electrons at each measurement position based on the detection signals from the electron detectors 4-1 to 4-4 fixed at each measurement position (step S34).

  The processing of steps S35 to S38 is the same as the processing of steps S5 to S8 of the analysis method shown in FIG. When the scan of the scanning range is completed, the rotation mechanism 15 rotates the electron detectors 4-1 to 4-4 to the next measurement position under the control of the rotation mechanism control circuit 16 (step S39).

  The rotation mechanism control circuit 16 determines whether or not the detection at all measurement positions is completed (step S40), and if not completed, the rotation mechanism control circuit 16 repeats the processing from step S32.

  When scanning at all measurement positions is completed, the control computer 22 detects the detection results of the electron detectors 4-1 to 4-4 at four measurement positions for each irradiation position from the stored detection results of secondary electrons. Find the added value of. Then, the control computer 22 calculates the spin component of the secondary electrons emitted from the irradiation position from the equations (3) and (4), and analyzes the magnetization vector of the sample surface uniquely determined from the spin component (step). S41).

  Note that the measurement time in step S34 is T / 4, where T is the measurement time for obtaining the number of electrons necessary for analysis at each irradiation position of the primary electron beam on the sample surface. Thereby, when the electron detectors 4-1 to 4-4 are rotated and the detection at all measurement positions is completed, the measurement time per irradiation position becomes T, and a sufficient number of electrons can be obtained. , Increase in measurement time can be prevented.

  As described above, in the surface analysis device 10 and the analysis method according to the first embodiment, the sum of the detection values of the secondary electrons detected by the electron detectors 4-1 to 4-4 is used at a plurality of measurement positions. Find the spin component. Thereby, it is possible to reduce the influence of variation in multiplication factor between the electron detectors 4-1 to 4-4, and to analyze the magnetization distribution on the sample surface with high accuracy.

  In the analysis methods shown in FIGS. 5, 7, and 8, the case where the Y coordinate is determined first and scanning in the X-axis direction has been described. However, the X coordinate is determined first and the Y-axis direction is determined. Needless to say, scanning may be performed.

The calculation of the spin component may be performed by software of the control computer 22, but may be performed by hardware by the detection signal processing circuit 18.
By the way, the control computer 22 or the detection signal processing circuit 18 obtains in advance a correction value for correcting the variation in multiplication factor among the electronic detectors 4-1 to 4-4, and based on the correction value during actual measurement. The detection values of the electron detectors 4-1 to 4-4 may be corrected. The correction value is obtained as follows.

  The beam scanning system control circuit 20 controls the SEM column 14 to irradiate the position where the sample surface is not magnetized or the sample stage 13 with the primary electron beam. At this time, the spin direction of the emitted secondary electrons is random.

  The rotation mechanism control circuit 16 rotates the electron detectors 4-1 to 4-4 by the rotation mechanism 15, and performs secondary operation at each measurement position (X +, X−, Y +, Y−) as shown in FIG. 3. Causes measurement of electrons.

  Here, the detection values at each measurement position of the electron detector 4-1 are (Sd1_X +, Sd1_X−, Sd1_Y +, Sd1_Y−), and the detection values at each measurement position of the electron detector 4-2 are (Sd2_X +, Sd2_X−). , Sd2_Y +, Sd2_Y−). The detection values at the measurement positions of the electron detector 4-3 are (Sd3_X +, Sd3_X-, Sd3_Y +, Sd3_Y-), and the detection values at the measurement positions of the electron detector 4-4 are (Sd4_X +, Sd4_X-, Sd4_Y +, Sd4_Y−).

At this time, the control computer 22 or the detection signal processing circuit 18 obtains average values SDA1 to SDA4 of the detection values of the respective electron detectors 4-1 to 4-4 from the following equations.
SDA1 = {(Sd1_X +) + (Sd1_X −) + (Sd1_Y +) + (Sd1_Y −)} / 4 (5)
SDA2 = {(Sd2_X +) + (Sd2_X −) + (Sd2_Y +) + (Sd2_Y −)} / 4 (6)
SDA3 = {(Sd3_X +) + (Sd3_X −) + (Sd3_Y +) + (Sd3_Y −)} / 4 (7)
SDA4 = {(Sd4_X +) + (Sd4_X −) + (Sd4_Y +) + (Sd4_Y −)} / 4 (8)
Next, the control computer 22 or the detection signal processing circuit 18 calculates the ratio of the average value SDA = (SDA1 + SDA2 + SDA3 + SDA4) / 4 of SDA1 to SDA4 and SDA1 to SDA4 to the correction value of each electron detector 4-1 to 4-4. Obtained as P1 to P4. That is, the correction values P1 to P4 are obtained as follows.
P1 = SDA1 / SDA (9)
P2 = SDA2 / SDA (10)
P3 = SDA3 / SDA (11)
P4 = SDA4 / SDA (12)
In actual measurement, the spin component can be calculated with higher accuracy by multiplying SD1 in Equations (3) and (4) by P1, SD2 by P2, SD3 by P3, and SD4 by P4.

  In this case, even if the electron detectors 4-1 to 4-4 are not rotated at the time of actual measurement, those obtained by multiplying the correction values P1 to P4 by SD1 to SD4 in the equations (1) and (2) are used. Even so, the spin component can be calculated with high accuracy.

  In the above description, the case where there are four electron detectors has been described. However, the number is not limited to this. For example, only the two electron detectors 4-1 and 4-3 arranged opposite to each other as shown in FIG. 3 may be used.

In this case as well, the rotation mechanism control circuit 16 rotates the two electron detectors 4-1 and 4-3 every 90 ° while simultaneously performing the secondary measurement at two measurement positions on the X axis or the Y axis. Let the electrons be detected. Then, the control computer 22 adds the secondary electron detection values (SD1 + SD3) _X +, (SD1 + SD3) of the electron detectors 4-1, 4-3 at the four measurement positions (X +, X−, Y +, Y−). _X−, (SD1 + SD3) _Y +, (SD1 + SD3) _Y− are obtained. The spin component is obtained as follows based on these added values.
Sx = {(SD1 + SD3) _X +}-{(SD1 + SD3) _X-} (13)
Sy = {(SD1 + SD3) _Y +}-{(SD1 + SD3) _Y-} (14)
That is, a plurality of electron detectors are obtained by rotating a plurality of electron detectors to obtain detection values at four measurement positions (X +, X−, Y +, Y−) and obtaining a spin component from the added value. The influence of variations in the multiplication factor can be reduced. This makes it possible to analyze the magnetization distribution on the sample surface with high accuracy.

The correction values described above can also be calculated and used as follows, as in the case of four electron detectors.
The detection values at each measurement position of the electron detector 4-1 are (Sd1_X +, Sd1_X−, Sd1_Y +, Sd1_Y−), and the detection values at each measurement position of the electron detector 4-3 are (Sd3_X +, Sd3_X−, Sd3_Y +, Sd3_Y−). At this time, average values SDA1 and SDA3 of detection values of the electron detectors 4-1 and 4-3 are as follows.
SDA1 = {(Sd1_X +) + (Sd1_X −) + (Sd1_Y +) + (Sd1_Y −)} / 4 (15)
SDA3 = {(Sd3_X +) + (Sd3_X −) + (Sd3_Y +) + (Sd3_Y −)} / 4 (16)
The ratio between the average value SDA = (SDA1 + SDA3) / 2 of SDA1 and SDA3 and SDA1 and SDA3 is set as the correction values P1 and P3 of the electron detectors 4-1 and 4-3. That is, the correction values P1 and P3 are as follows.
P1 = SDA1 / SDA (17)
P3 = SDA3 / SDA (18)
In actual measurement, the spin component can be calculated with higher accuracy by multiplying SD1 by P1 and SD3 by P3 in equations (13) and (14).

  In the above, four measurement positions (X +, X−, Y +, Y−) of the electron detector for measuring the scattering direction distribution of the secondary electrons are set to four or more. Assuming that the number of measurement positions is m, in the pixel addition method analysis method shown in FIG. 5 and the analysis method shown in FIG. 8, one measurement time of the electron detector at each measurement position is T / m. It becomes. In the analysis method of the surface addition method shown in FIG. 7, the measurement time for one electron detector at each measurement position is T / (n × m), where n is the number of surface additions.

In this case as well, the spin component of the secondary electrons can be calculated based on the added value of the detection values of the plurality of electron detectors at each measurement position.
Next, the second factor in which it is difficult to obtain an accurate count value of incident electrons (scattered secondary electrons) with the electron detector of the surface analyzer will be described.

  FIG. 9 is a diagram showing how incident electrons are detected. FIG. 9A shows a case where one secondary electron is incident on the electron detector, and FIG. 9B shows a plurality of secondary electrons simultaneously detected by the electron detector. The case where it injects into is shown.

  As shown in FIG. 9A, when one secondary electron 8 is incident on the channeltron electron multiplier 4a which is the electron detectors 4-1 to 4-4, the channeltron electron multiplier 4a. Is multiplied by the preamplifier 6a. The discriminator 6b outputs one pulse when the charge amount exceeds a certain amount, and the counter 6c counts this pulse as one electron.

  On the other hand, as shown in FIG. 9B, when two secondary electrons 8a and 8b are simultaneously incident on the channeltron electron multiplier 4a, the upper limit of the number of multiplying electrons of the channeltron electron multiplier 4a. Two pulses are not output due to dead time or dead time. This causes a count loss.

Hereinafter, a surface analysis apparatus and an analysis method for preventing a decrease in analysis accuracy due to a count loss at the time of simultaneous incidence on an electron detector of a plurality of electrons as shown in FIG. 9B will be described.
(Second Embodiment)
FIG. 10 is a diagram illustrating a schematic configuration of a main part of the surface analysis apparatus according to the second embodiment.

The same components as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
In the surface analyzer 50, the electron spin analyzer 12 a includes a lead electrode 51, a beam deflecting unit 52, and an acceleration tube 53. Further, the surface analysis apparatus 50 includes a pulse voltage supply unit 54 that applies a pulse voltage to the lead-in electrode 51. Note that the pulse voltage supply unit 54 may be provided in the electron spin analyzer 12a. Also, the number of electron detectors is not limited to four.

  A pulse voltage is applied to the drawing electrode 51, and the beam-shaped secondary electrons emitted from the surface of the sample 2 are pulsed by the irradiated primary electrons, and are drawn in the direction of the target 3 in the electron spin analyzer 12a. . Hereinafter, the pulsed secondary electron beam is referred to as a secondary electron pulse.

The beam deflection unit 52 performs convergence of the drawn secondary electron pulse and scanning deflection.
The acceleration tube 53 accelerates the secondary electron pulse to collide with the target 3.
Note that the pulse voltage supply unit 54 multiplies the cycle of the pulse voltage from when electrons enter the electron detectors 4-1 to 4-4 such as channeltron electron multipliers until they are output. It is determined from the required time Tt or the dead time Td of the electron detectors 4-1 to 4-4. Even if electrons are incident between Tt and Td, the counter 6c does not acquire the count value, which is wasted. Therefore, the pulse voltage supply unit 54 makes the half cycle of the pulse voltage equal to or greater than, for example, the larger one of Tt and Td so that electrons are not incident during this period.

  FIG. 11 is a diagram illustrating a difference in secondary electrons drawn due to a difference in voltage applied to the drawing electrode. FIG. 11A shows a case where a DC voltage is applied to the lead electrode 51, and FIG. 11B shows a case where a pulse voltage is applied to the lead electrode 51.

  As shown in FIG. 11A, when a constant DC voltage is applied to the drawing electrode 51, the drawn secondary electrons are in the form of a beam. On the other hand, as shown in FIG. 11B, when a pulse voltage is applied to the drawing electrode 51, the drawn secondary electron beam also has a pulse shape.

  Thus, by making the drawn secondary electrons into a pulse shape, the scattered secondary electrons detected by the electron detectors 4-1 to 4-4 also become a pulse shape. This makes it possible to reduce the temporal electron density of the secondary electrons that reach the electron detectors 4-1 to 4-4, and a plurality of secondary electrons are simultaneously incident on one electron detector. This can be suppressed, and the count loss of the number of electrons can be suppressed.

  The results detected by the electron detectors 4-1 to 4-4 and counted by the signal processing unit 6 are input to the arithmetic processing unit 7, where the calculations according to the equations (1) and (2) are performed and the spin is performed. An x component Sx and a spin y component Sy are obtained.

  In the surface analysis apparatus 50 of the present embodiment, the count loss of the number of electrons due to the electron detectors 4-1 to 4-4 can be suppressed, so that the spin x component Sx and the spin y component Sy can be obtained with high accuracy. The magnetization distribution on the surface of the sample 2 can be analyzed with high accuracy.

The pulse voltage supply unit 54 may apply a pulse voltage as shown below to the lead-in electrode 51 instead of the rectangular pulse as shown in FIG.
FIG. 12 is a diagram illustrating a modification of the pulse voltage applied to the lead-in electrode.

  The pulse voltage supply unit 54 may adjust the time constant to increase the rise time or fall time of the pulse, and generate a pulse voltage with a blunt waveform like a chirp pulse as shown in FIG. Good.

  The secondary electrons receive energy corresponding to the electrode voltage at the timing of passing through the drawing electrode 51. That is, when the electrode voltage at the timing of passing through the drawing electrode 51 is different, the speed of the drawn secondary electrons also changes.

  Therefore, when the pulse voltage supply unit 54 applies a pulse voltage as shown in FIG. 12 to the drawing electrode 51, the drawn secondary electrons can be pulsed, and at the same time, the velocity component distribution of electrons contained in the secondary electron pulse. Can spread. As a result, the spatial density of electrons contained in one pulse can be reduced, so that secondary electrons are simultaneously input to one of the electron detectors 4-1 to 4-4 and a count loss occurs. Can be suppressed.

Hereinafter, an example of the entire configuration of the surface analysis apparatus including the main part illustrated in FIG. 10 will be described.
FIG. 13 is a diagram illustrating a configuration of an example of a surface analysis apparatus according to the second embodiment.
The same components as those shown in FIGS. 4 and 10 are denoted by the same reference numerals. The surface analysis apparatus 60 shown in FIG. 13 includes a lens 55, a lens control circuit 56, a deflection signal control circuit 57, and an acceleration voltage control circuit 58 in addition to the above-described configuration.

The lens 55 is provided in the electron spin analyzer 12 b and converges secondary electrons drawn by the drawing electrode 51.
The lens control circuit 56 controls the voltage applied to the lens 55.

The deflection signal control circuit 57 controls the voltage applied to the beam deflection unit 52.
The acceleration voltage control circuit 58 controls the voltage applied to the acceleration tube 53.
The pulse voltage supply unit 54, the lens control circuit 56, the deflection signal control circuit 57 and the acceleration voltage control circuit 58 are controlled by the detector control circuit 17. These may be provided in the electron spin analyzer 12b.

  Note that the vacuum chamber 11 as shown in FIG. 4 is not shown. The target 3 is applied with a voltage equivalent to the final acceleration voltage in the accelerating tube 53, for example, about 20 kV to 120 kV, but the configuration is not shown.

  The analysis process using the surface analyzer 60 as described above is almost the same as that described in the flowcharts shown in FIGS. That is, under the control of the control computer 22, the initial setting and the irradiation position of the primary electron beam are determined, and the secondary electron detection process is performed.

  When primary electrons are irradiated from the SEM column 14 to the sample 2, secondary electrons are emitted from the surface of the sample 2. As described above, since a pulse voltage is applied to the drawing electrode 51 by the pulse voltage supply unit 54, the drawn secondary electrons are pulsed. The secondary electron pulse is converged by the lens 55 and collides with the target 3 via the beam deflection unit 52 and the acceleration tube 53.

  Secondary electrons scattered by the target 3 are detected by electron detectors 4-1 to 4-4 fixed at the respective measurement positions. Then, the detection signal processing circuit 18 counts the number of secondary electrons at each measurement position based on the detection signals from the electron detectors 4-1 to 4-4.

  As described above, by drawing the secondary electrons with the pulse voltage, it becomes possible to reduce the temporal electron density of the secondary electrons detected by the electron detectors 4-1 to 4-4. It can suppress that a secondary electron is simultaneously incident on one electron detector 4-1 to 4-4. Thereby, the count loss in the detection signal processing circuit 18 is suppressed, and counting can be performed with high accuracy. Further, as shown in FIG. 12, the pulse voltage supply unit 54 generates a pulse voltage having a dull pulse waveform by increasing the rise time and the fall time of the pulse, and applying the pulse voltage to the lead-in electrode 51. The spatial density of electrons contained in one pulse can be lowered. Thereby, it can further suppress that a secondary electron is simultaneously input into the electron detectors 4-1 to 4-4, and count loss generate | occur | produces.

  When the counting of the number of secondary electrons at each measurement position is completed, for example, the control computer 22 calculates the spin components Sx and Sy at the incident position of the primary electrons by the above-described equations (1) and (2). . The spin components Sx and Sy correspond to the x component and the y component of the magnetic vector at the irradiation position of the primary electron beam of the sample 2. Then, the magnetization distribution on the surface of the sample 2 can be analyzed by obtaining the spin components Sx and Sy at the respective irradiation positions of the sample 2 by the processing as shown in FIGS.

As described above, the surface analysis apparatus 60 of the present embodiment can suppress the count loss of secondary electrons, so that the magnetization distribution on the surface of the sample 2 can be analyzed with high accuracy.
In order to reduce the spatial density of secondary electrons, the beam deflecting unit 52 may scan the secondary electron pulse in one or two dimensions as follows.

FIG. 14 is a diagram illustrating a state in which the secondary electron pulse is scanned in one dimension.
FIG. 14 further shows an example of a voltage waveform generated by the deflection signal control circuit 57. The horizontal axis is time, and the vertical axis is applied voltage. Here, the illustration of the configuration of the acceleration tube 53 shown in FIG. 13 is omitted.

  The beam deflection unit 52 includes a pair of electrodes 52-1 and 52-2 that face each other. A sawtooth voltage as shown in FIG. 14 is applied to one electrode 52-1 from the deflection signal control circuit 57, and the other electrode 52-2 is grounded. When the applied voltage to the electrode 52-1 is changed between Va, Vb (0 V), and Vc, the deflection signal control circuit 57 generates a secondary electron pulse between point A and point C, centering on point B. It is possible to scan in a one-dimensional direction.

FIG. 15 is a diagram showing how the secondary electron pulse is scanned two-dimensionally.
FIG. 15 further shows an example of two types of voltage waveforms generated by the deflection signal control circuit 57. The horizontal axis is time, and the vertical axis is applied voltage.

  The beam deflection unit 52 has two sets of electrodes 52-1 and 52-2 and electrodes 52-3 and 52-4 facing each other. One set of electrodes 52-1 and 52-2 and the other set of electrodes 52-3 and 52-4 are orthogonal to each other. The deflection signal control circuit 57 applies a sawtooth voltage having a different period to the electrodes 52-1 and 52-3. The electrodes 52-2 and 52-4 are grounded.

  In the example of FIG. 15, the deflection signal control circuit 57 applies a voltage that changes between the voltages Va−Vc as shown in FIG. 14 to the electrode 52-3. A secondary electron pulse is scanned in the direction. Further, the deflection signal control circuit 57 applies a voltage having a period four times the voltage waveform applied to the electrode 52-3 to the electrode 52-1. When the deflection signal control circuit 57 changes the voltage applied to the electrode 52-1 between Vd, Ve (0 V), and Vf, the Y direction of the target 3 is between the point D and the point C with the point E as the center. A secondary electron pulse is scanned. As a result, four X-direction scans are performed per scan surface.

  As described above, by scanning the secondary electron pulse in one or two dimensions, the secondary electron pulse is spatially dispersed, and the scattered electron density detected by the electron detectors 4-1 to 4-4 is changed. It can be reduced in time and space. Thereby, it can further suppress that a plurality of electrons are simultaneously incident on the electron detectors 4-1 to 4-4.

At this time, it is desirable to use the electron detectors 4-1 to 4-4 having a position resolution, for example, having a plurality of detection channels (multiple channels).
FIG. 16 is a diagram illustrating an example of a multi-channel electron detector.

  Since the secondary electron pulse scanned in one or two dimensions has a low spatial electron density, it is scattered by the target 3 by using a multi-channel electron detector 4b as shown in FIG. The detection efficiency of scattered electrons can be improved. When scattered electrons enter each channel of the multi-channel electron detector 4b, a pulse is generated by the preamplifier / discriminator 6d connected to each channel.

As the multi-channel electron detector 4b, for example, there is MCP which is a kind of electron multiplier.
As described above, the surface analysis apparatus for preventing a decrease in analysis accuracy due to a count loss at the time of simultaneous incidence of a plurality of electrons on the electron detector has been described. However, as in the first embodiment, the electron detector 4-1 ˜4-4 may be rotated. That is, as shown in FIG. 4, the electron detectors 4-1 to 4-4 are rotated by the rotation mechanism 15 or the rotation mechanism control circuit 16, and the detection of the electron detectors 4-1 to 4-4 at each detection position. The spin component may be obtained using the sum of values. Thereby, the influence of the dispersion | variation in the multiplication factor between the electron detectors 4-1 to 4-4 can be reduced, and also the magnetization distribution on the sample surface can be analyzed with high accuracy.

As described above, one aspect of the surface analysis apparatus and the analysis method of the present invention has been described based on a plurality of embodiments, but these are only examples and are not limited to the above description.
The following additional notes are further disclosed with respect to the plurality of embodiments described above.

(Supplementary note 1) A metal target for colliding and scattering secondary electrons emitted from a sample,
A plurality of electron detectors for detecting the scattered secondary electrons;
A rotating unit that rotates each of the electron detectors to a plurality of measurement positions with a direction perpendicular to the sample surface as a rotation axis;
An arithmetic processing unit that calculates a spin component of the secondary electrons based on an addition value of detection values of the plurality of electron detectors at each measurement position;
A surface analysis apparatus comprising:

  (Additional remark 2) When the measurement time of the said secondary electron per each irradiation position of the primary electron beam in the said sample is set to T, and the number of the said measurement positions is set to m, the said rotation part is each said each of the said electron detector. The surface analysis apparatus according to appendix 1, wherein the electron detector is rotated so that one measurement time at the measurement position is T / m.

  (Supplementary Note 3) T is the total measurement time of the secondary electrons per each irradiation position of the primary electron beam in the sample, n is the number of times of irradiation of the primary electron beam to the same sample (n ≧ 2), When the number of measurement positions is m, the rotating unit sets the electron detector so that one measurement time at each measurement position of the electron detector is T / (n × m). The surface analysis apparatus according to appendix 1, wherein the surface analysis apparatus is rotated.

  (Additional remark 4) The said arithmetic processing part calculates a correction value beforehand from the said detected value in each said measurement position for every said electron detector, and correct | amends the said detected value based on the said corrected value at the time of an actual measurement The surface analysis apparatus according to any one of appendices 1 to 3, wherein

  (Supplementary Note 5) The correction value is calculated based on the detection value of the secondary electrons emitted from the non-magnetized region by irradiating the non-magnetized region of the sample with the primary electron beam. The surface analysis apparatus according to appendix 4, characterized by:

(Appendix 6) A metal target for colliding and scattering secondary electrons emitted from a sample;
A pulling electrode to which a pulse voltage is applied, pulsates the beam-shaped secondary electrons emitted from the sample, and draws them in the direction of the metal target;
A pulse voltage supply for applying the pulse voltage to the lead-in electrode;
A plurality of electron detectors for detecting the secondary electrons scattered and pulsed by the metal target;
A surface analysis apparatus comprising:

  (Supplementary Note 7) The pulse voltage supply unit applies the pulse voltage, whose rise time or fall time is increased by adjusting a time constant, to the drawing electrode, and the speed of the secondary electrons passing through the drawing electrode The surface analyzer according to appendix 6, wherein the component distribution is widened.

  (Additional remark 8) It has a deflection | deviation part which makes the said secondary electron drawn by the said drawing electrode 1-dimensionally scans or 2-dimensionally scans on the said metal target, The said electron detector has a some detection channel, and on the said metal target The surface analysis apparatus according to any one of appendix 6 or 7, wherein the secondary electrons scattered at different positions are detected.

(Supplementary Note 9) Secondary electrons emitted from a sample and collided with a metal target and scattered are detected by a plurality of electron detectors arranged at a plurality of measurement positions,
The rotating unit rotates each of the electron detectors with the direction perpendicular to the sample surface as a rotation axis, moves to the next measurement position, and repeats the detection process of the secondary electrons,
An analysis method comprising: calculating a spin component of the secondary electrons based on an addition value of detection values of a plurality of the electron detectors at each measurement position.

(Additional remark 10) Applying a pulse voltage to the drawing electrode for drawing the secondary electron emitted from the sample in the direction of the metal target to pulse the secondary electron,
An analysis method, wherein the secondary electrons scattered and pulsed by the metal target are detected by an electron detector.

(Supplementary Note 11) A metal target for colliding and scattering secondary electrons emitted from a sample;
A pulling electrode to which a pulse voltage is applied, pulsates the beam-shaped secondary electrons emitted from the sample, and draws them in the direction of the metal target;
A plurality of electron detectors for detecting the secondary electrons scattered and pulsed by the metal target;
An electron spin analyzer characterized by comprising:

DESCRIPTION OF SYMBOLS 1 Surface analyzer 2 Sample 3 Target 4-1, 4-2, 4-3, 4-4 Electron detector 5 Rotating part 6 Signal processing part 7 Arithmetic processing part

Claims (8)

A metal target for colliding and scattering secondary electrons emitted from the sample;
A plurality of electron detectors for detecting the scattered secondary electrons;
A rotating unit that rotates each of the electron detectors to a plurality of measurement positions with a direction perpendicular to the sample surface as a rotation axis;
An arithmetic processing unit that calculates a spin component of the secondary electrons based on an addition value of detection values of the plurality of electron detectors at each measurement position;
A surface analysis apparatus comprising:   When the measurement time of the secondary electrons per each irradiation position of the primary electron beam in the sample is T, and the number of the measurement positions is m, the rotating unit is at each measurement position of the electron detector. The surface analysis apparatus according to claim 1, wherein the electron detector is rotated so that one measurement time is T / m.   The total measurement time of the secondary electrons per each irradiation position of the primary electron beam in the sample is T, the number of times of irradiation of the primary electron beam to the same sample is n (n ≧ 2), and the measurement position When the number is m, the rotating unit rotates the electron detector so that one measurement time at each measurement position of the electron detector is T / (n × m). The surface analysis apparatus according to claim 1, wherein: A metal target for colliding and scattering secondary electrons emitted from the sample;
A pulling electrode to which a pulse voltage is applied, pulsates the beam-shaped secondary electrons emitted from the sample, and draws them in the direction of the metal target;
A pulse voltage supply for applying the pulse voltage to the lead-in electrode;
A plurality of electron detectors for detecting the secondary electrons scattered and pulsed by the metal target;
A surface analysis apparatus comprising:   The pulse voltage supply unit applies the pulse voltage whose time constant is adjusted to increase the rising time or the falling time to the drawing electrode, and widens the velocity component distribution of the secondary electrons passing through the drawing electrode. The surface analysis apparatus according to claim 4.   A deflection unit configured to perform one-dimensional scanning or two-dimensional scanning of the secondary electrons drawn by the drawing electrode on the metal target; and the electron detector includes a plurality of detection channels at different positions on the metal target. 6. The surface analysis apparatus according to claim 4, wherein the scattered secondary electrons are detected. Secondary electrons emitted from the sample, colliding with the metal target and scattered are detected by a plurality of electron detectors arranged at a plurality of measurement positions,
The rotating unit rotates each of the electron detectors with the direction perpendicular to the sample surface as a rotation axis, moves to the next measurement position, and repeats the detection process of the secondary electrons,
An analysis method comprising: calculating a spin component of the secondary electrons based on an addition value of detection values of a plurality of the electron detectors at each measurement position. Applying a pulse voltage to the drawing electrode for drawing the secondary electrons emitted from the sample in the direction of the metal target to pulse the secondary electrons;
An analysis method, wherein the secondary electrons scattered and pulsed by the metal target are detected by an electron detector.

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