WO2007119873A1 - Scanning type electronic microscope - Google Patents

Abstract

Magnetic field generating efficiency of the object lens of an electronic microscope provided with a semi-infinite lens type object lens is improved, and power consumption of the exciting coil of the object lens is reduced. Charge of an insulation sample is neutralized to enable stable distance measurement. The electronic microscope comprises, in order to increase a filed strength on an optical axis, a magnetic disc (18) disposed in the vicinity of a magnetic pole gap to be independent of an object lens (3) with the center axis of the disc aligned with the optical axis. This magnetic disc is disposed with a space between it and the object lens (3) (a space between the disc (18) and a lower magnetic pole (16)) so as to increase magnetic resistance with respect to the object lens (3).

Description

 Meiji book Scanning electron microscope

Technical field

 The present invention relates to an electron microscope, and in particular, to an improvement in an electron microscope having, for example, a semi-lens type object lens configuration. Me In addition, it is related to band suppression technology, which is a problem when observing an insulator sample with an electron microscope.

M) is a technique for stably measuring the length of a note composed on a reticle that easily accumulates charges due to electron beam irradiation. ο

Background art

 t '

 As one of the means to reduce the diameter of the spot when the electron beam converges on the material by reducing the high resolution BE of the crystal, reducing the aberration of the optical system If it is effective to make the main surface of the objective lens close to the material, it is effective to place the material between the upper and lower magnetic poles of the objective lens. A lens-type structure in which the material is placed in the magnetic field created by the <> is placed under the upper and lower magnetic poles of the objective lens, but the magnetic field is positively charged. Occurrence of leaking cereal lens type

 In the lens type, the material is placed in the gap between the upper and lower magnetic poles, so the magnetic field of the object lens can be used more efficiently.

 , Because the mechanism of the fee (stage) is limited, a large ceremony fee cannot be observed o

 Se ヽ *

In the lens type, the magnetic field that leaks on the center axis of the object lens is used from the gap cap of the pole of the objective lens located 5 ^ above the material. Therefore, the energy that excites the objective lens against the magnetic field strength that can be used effectively The working distance (WD; W ork 1 ng) D stan stan C e, which is the distance between the objective lens and the sample, in order to achieve the same resolution AH 匕 b If you decrease <) or increase the energy level of the electron beam to be converged, a large amount of power will be consumed. If the extinction force is <large, the heat generated by the coil that excites the objective lens also increases, so a cooling device for the objective lens is required depending on the mouth.

< On the other hand, since the space between the lens and the lens type can be secured below the objective lens, the arrangement of the electrodes necessary for the stage and the electron optical system is required. Constrained by V. o V or large sample: Can be handled, so it can be widely used in inspection equipment such as semiconductors.

 In Japanese Patent Application Laid-Open Publication No. Hei 10 1 1 0 6 4 6 6 (hereinafter referred to as Patent Document 1), there is an object lens to suppress the magnetic field leaking from the electron optical system to the material side. Cover the bottom pole piece of the lens with gas shield ', the magnetic lens of the objective lens

 However, a magnetic field type objective lens that is configured so as not to leak to the charge side is explained.

 In Japanese Patent Publication No. 2 0 0 6 1 5 4 0 94 (referred to as Patent Document 2), there is a predetermined size between the semi-lens type objective lens and the fee. Place a flat i-pole with an opening of #

 By applying a predetermined voltage to the pole, the technology that reduces the level gradient of the insulating material and stabilizes the S / N and the contrast of the image has been clarified. O Disclosure of invention

 However, it uses a lens and lens type objective lens, and W

When D is smaller, a strong magnetic field acts on the surface of the material, so B ^, secondary electrons and backscattered electrons generated when the electron beam is incident on the material, etc. The next electron has the shortcoming of being strongly focused and focused between the sample and the objective lens. Magnetic field mis

The electrons that have received the fea are placed in the objective lens and rise spirally around the optical axis, which is the axis, within a radius of about 1 m. If the field strength begins to decrease after passing through the magnetic pole of the lens, the binding force due to the magnetic field of the electron will decrease, and the energy (velocity) and angle during launch from the material will decrease. At the same time, the orbit will begin to diverge. Therefore, an electron with a small energy at the time of emission like a secondary electron causes a secondary electron (including the primary and reflector) to move upward from the objective lens. Detect with

In the TTL (Thro U gh T: he then 6 ns) method, the trajectory is changed with an EXB filter or the like, and captured with an electronic detector with high efficiency. There are 5 methods, but this method can capture electrons with low energy, but the largest back-scattered electrons are EXB. When the trajectory is changed with a filter, the divergence occurs more strongly when the magnetic field intensity decreases due to the force on the objective lens, and spreads at a large angle. The yield at detection 38. decreased significantly5.

 Of course, as an electron microscope application, it is also important to distinguish and image primary electrons and backscattered electrons that have different information on the surface of the surface. In order to detect backscattered electrons at _, a plurality of conversion electrodes that collide the divergent reflected protons to generate primary electrons are placed near the objective lens. It is also done.

 However, since the reflected electrons diverge with a wide angular distribution, the reflector that collides with the conversion electrode has a limited emission angle, and the primary electrons of the reflector are The effective detection efficiency is not high due to the low conversion efficiency and the difficulty in controlling the secondary electrons generated from the conversion electrode to the detection.

 Therefore, as a method of making the detection efficiency higher, it is possible to set M c P (M 1 C ro C h a n n e 1 P l a t e) between the objective lens and the sample.

 απ

A thin child detector, such as a semi-conductor detector, is used to detect reflected electrons directly. However, if the WD is small as described in the IU, it is a fee. The child generated from the laser beam is focused on the object lens by the presence of the magnetic field, and is used for the primary electron beam that irradiates the material. At the center of child detection, the probability of passing a hole with a diameter of several millimeters is <and the detection efficiency was reduced.

 -The magnetic field on the material has a great influence on the detection efficiency. X. Not only is the magnetic field changed to magnetization when observing the formula with magnetic information. This is an objective lens that does not act on the material in question (features such as the magnetic recording information being erased). As described in Patent Document 1, there are five arc-lens type magnetic lenses, and an electric field is used as an objective lens with no field generation. In the case of electrostatic lenses, it is necessary to apply a high voltage to the lens white body, which is advantageous from the viewpoint of feasibility and performance. However, it is difficult to obtain the same resolution as the cereal lens unless the WD is made smaller. It is ing significantly sexual at low acceleration pressure

 In addition, there are a wide range of observation fees for electron microscopes, but among them, the observation of isolated materials is charged particle beam irradiation! 'Due to the effect of this electric charge, the trajectory of the particle beam is deviated due to the potential gradient generated when the surface potential of the material becomes uneven within the charged particle beam irradiation region. (Bi-do riff

 ) In addition, the amount of secondary electron emission changes due to the shadow of the charge m, and the original structure of the material cannot be observed.

Using a scanning microscope as represented by M, it is possible to measure the pattern on the material that is easily scalloped by the electron beam irradiation of a reticule at a high level. It is difficult

In the five-stage electron microscope described in Patent Document 2, the charge of the secondary electron beam is determined by specifying the incident energy of the secondary electron beam so that the secondary electron emission rate is 1 or more. The surface distribution is controlled according to the shape of the plate electrode for band suppression and the shape of the material, which has a positively charged surface and is arranged between the surface of the material and the objective lens. However, the technique described in Patent Document 2 is used for reticle observation, while enabling measurement of the size of a chip and the like. Although it is an effective method, it is difficult to completely eliminate the effects of charging. In particular, AEI (After Etch Inspection), ADI (After Development Inspection), and the surface of the reticle with the resist applied to the surface of the reticule- For materials with a large band change depending on energy, stable measurement repeatability may not be obtained.To improve measurement accuracy Need further suppression of the band

 The present invention was developed from the background of the above-mentioned technical background, and the objective lens of an electron microscope equipped with an X-lens objective lens X. The magnetic field generation efficiency of the lens is improved, the power consumption of the excitation lens of the objective lens is reduced, and the charging of the insulating material due to the charged beam irradiation is suppressed. In this way, we can provide an i-microscope capable of observing insulating materials with high resolution at high resolution.

In the lens lens, the objective lens is opened to the material side in order to actively leak the magnetic field onto the material and bring the lens main surface closer to the material. It is normal to have a gap (gap between upper pole 15 and lower pole 16), but to converge the primary electron beam that illuminates the material. Is the magnetic field leaked from the magnetic pole group with the strongest strength <the objective lens _t ,

 Since it was divided on the optical axis that coincided with the central axis, the intensity was less than the magnetic field in the pole gap, so the above problem was solved. Therefore, in the electron microscope according to the present invention, in order to increase the magnetic field strength on the optical axis, a magnetic disk that is independent of the objective lens near the magnetic pole gap is used. The center axis of the disk and the optical axis are aligned with each other.

 Since this magnetic disk increases the magnetoresistance with the objective lens, the objective lens has a space (the space between the disk 18 and the lower magnetic pole 16).

·>-If it is placed far away, the leakage magnetic field from the magnetic pole Can be led to the disk, and if there is no m

 -The efficiency of the magnetic field on the optical axis can be increased rather than forming a field. The reason why the shape is a disk is to use the magnetic field of an axisymmetric objective lens without asymmetry.

 To set a magnetic disk with a space for the objective lens *

 -It is necessary to avoid magnetic saturation by introducing a magnetic field stronger than necessary, as well as a lens-type objective lens that originally has no magnetic disk. This is because it is convenient for improving the magnetic field strength on the optical axis. Since the magnetic field, which is isolated from the lens and reduced in the air, is taken into the magnetic disk, there is no magnetic saturation even if the disk is thin. Since the magnetic field does not leak from the surface of the sample side, the effect of shielding the leakage magnetic field on the material is very large.

 Here, due to the shielding effect of the leakage magnetic field by the magnetic disk, the magnetic field BZ of the material normal direction component on the material and the magnetic field B r of the water direction component of the material water Although the intensity of the light decreases, the intensity of Br increases near the optical axis. Electrons (secondary electrons and reflected electrons) emitted from the material by increasing the intensity of Βr in the vicinity of the optical axis are more in the material direction than when the magnetic field is not shielded. The effect of returning to

 In the measurement of the reticle using the current measurement length s Ε Μ, the image generation is performed with the primary surface generated in a positively charged state with a primary generation efficiency of 1 or more. Yeah. 'Therefore, the effect of the magnetic field shielding by the ¾ body disk is considered.

 -As the amount of return of the electron emitted from the sample increases,

-The return of the emitted electrons that can suppress the charging of the positively charged part m. And the alignment of the return position on the sample is the electron beam provided on the magnetic disk. It is possible to change the magnetic field strength distribution on the sample by changing the diameter of the passage hole, and the band m is the most suppressed against changes in the sample and the incident energy. It is possible to set According to the present invention, a magnetic disk that is independent of the objective lens near the magnetic pole gap is placed with the central axis of the disk and the optical axis aligned. Therefore, for example, the magnetic field generation efficiency of the objective lens of an electron microscope equipped with a lens lens type objective lens can be revised, and the objective can be changed accordingly. In addition to being able to reduce the power consumption of the lens excitation coil, it is also possible to observe the insulator using an electron microscope due to the effect of magnetic field shielding by a magnetic disk. Therefore, it is possible to suppress electrification, and it is possible to provide an optical microscope with high resolution and high reproducibility.

 Figure 1 shows a scanning electron microscope (S) according to the first embodiment of the present invention.

Figure 2 is a diagram showing an example of the configuration of the magnetic disk punching mechanism.Figure 3 shows the improvement of the magnetic field strength on the optical axis in the first embodiment. Fig. 4A is a graph showing the conventional configuration for detecting backscattered electrons using the reflector trajectory and the conversion electrode using the Ding TL method. Fig. 4B shows an example of a conventional configuration in which reflected electrons are detected using the reflector trajectory and the TTL method with the detection of an optical type. Fig. 6 shows a conventional configuration example in which reflected electrons are detected using the detection of a circular type detector arranged between the reflector's orbit, the objective lens, and the charge. Fig.5B shows the trajectory of the reflector and the type of the circular type arranged between the objective lens and the charge according to the second embodiment of the present invention. Fig. 6, which is a diagram for explaining the method of detecting the reflector using the detection, shows the effect of reducing the magnetic field strength on the material surface in the second embodiment. Fig. 7 is a block diagram showing the automatic cutting function of the magnetic circle, and Fig. 8 is a diagram according to the third embodiment of the present invention. Fig. 9 is a diagram for explaining the orbits of primary electrons and backscattered electrons and how to detect backscattered electrons using the TTL method. Fig. 10 shows the configuration according to the fourth embodiment of the present invention. Fig. 10 shows the configuration according to the fifth embodiment of the present invention. Fig. 11 shows the magnetic shielding. Figure 12 is a diagram showing the concept of charging suppression by occluding action. Figure 12 shows the change in the magnetic field distribution on the formula fee in the case of a natural disk.

Figure 13 shows the change in the hole diameter of the magnetic disk 5, Br / B z, landing point position of the ejector, and return amount. Fig. 14 is a diagram showing an example of the formation of a magnetic disk switch, the best mode for carrying out the invention

 Refer to the attached drawing below and carry out this invention.

 In the embodiment according to the present invention described in the form, the field generation efficiency of the objective lens of the electron microscope equipped with the semi-lens type objective lens is improved. The power consumption of the objective lens excitation is reduced (the first topic) .In the embodiment according to the present invention, the cost of the child microscope using the objective lens is reduced. In addition to improving the detection efficiency of primary electrons (including secondary electrons and reflected electrons) generated from these materials (second problem), it is also possible to improve the physical lentices. Electron microscope capable of observing materials where the original characteristics of the field may be impaired by reducing the strength of the magnetic field leaking from (Third title) In addition, in observation of insulators using a child microscope, the magnetic field is shielded and the field strength is When the divided Ru alter the in that Kyosu the I One by ヽ insulator fee degrees reproducibility good rather observable child microscopic in high resolution obtained et been Ru charged curbing effect (fourth problem)

 First mode of implementation>

 Figure 1 shows a traveling i-microscope (S) according to the first embodiment of the present invention.

In this embodiment, which is a diagram showing the schematic diagram of (E), the measurement and inspection of the wiring on the top of the wire is performed for large materials such as semiconductor wafers. The secondary electron beam energy is also from a number of 100 eV to ke V. If you are a child who uses the composition for low-cost arrest of children, but the child is microscopic, the acceleration * pressure is large # < 5

 The child microscope of this embodiment is composed of a vacuum volume 1, a material 2 and an objective lens 3, and these internal parts are vacuumed from a vacuum level to a high vacuum level by a vacuum pump 4. O is an exhausted ring

 on

 In FIG. 1, the microscope has a group of electrostatic lenses that expand and contract the electron beam 5 and the electron beam 5 from the electron source 5 and the electron source 5 in the vacuum chamber 1. The field group for running the lens group 7 and the electron beam on the material 8 and the field lens <<is the electrostatic polarization 9 and the material 8 EXB filter for changing the orbit of the primary child generated from the laser: 1: 1 and the secondary electron are multiplied, and S Ε ί is TT detector type detection system consisting of an electron detector 12 for obtaining a sufficient air signal to form, and also the trajectory and shape of the electron beam are corrected. Have a means to do this X. o

 In the charge 2, a stage 1 3 with more than one axis for holding and moving the charge 8 is mounted.

Objective lens 3 is a lens lens type field lens that works most effectively with the present invention.The objective lens 3 is used for exciting a magnetic field in the upper part of objective lens 3. The coil 14 is equipped with a coil 14 that positively charges the magnetic field leaking from the gap 17 of the upper pole 15 and lower pole 16 into the air. In this form, a high resolution can be realized, but the magnetic field actually acting on the primary electron beam has leaked from the gap 17 onto the optical axis. Therefore, the efficiency of using the power of the excitation coil 14 is low>-. Therefore, the sex disk 1 8 is placed between the objective lens 3 and the fee 8, and the fee is reduced. O The leakage magnetic field to 8 is shielded more efficiently ο, and the body disk 1 8 can be inserted and removed by the punching machine 4 8. Depending on the type of signal and the type of sample, the disc 1 8 may be used. If you do not know what to do

 As shown in Fig. 1, the magnetic disk 18 can be arranged at the bottom of the lens group of the lens and lens type objective lens. As a result, it is possible to suppress the magnetic field leakage to the material while receiving the high resolution provided by the C-lens type objective lens. As shown in Fig. 1, when a magnetic disk with an electron beam passing open P is placed, the magnetic disk is substantially the same as the objective lens-

3 The upper magnetic pole is formed as a part of the magnetic path.

The field leaking from the lens gap V between the optical axis end of 15 and the optical axis end of the sexoid disk 18 has a lens action on the electron beam. That is, the lens main surface (where the maximum magnetic flux density is shown) is formed almost at the center between the upper pole 15 and the magnetic disk 18.

 According to the configuration like this, the fe sexual body is placed under the lens.

 Compared to this, it is possible to bring the lens main surface closer to the fee side, so the increase in the effective distance between the lens main surface and the fee is minimized. It is not just to suppress the field leakage <, and it is possible to make the magnetic disk function as a part of the magnetic path. It is possible to suppress the leakage of the magnetic field to the material while bringing the main surface close to the material.

 Fig. 2 is a diagram for explaining the configuration example of the punching mechanism of the magnetic disk 1 8. Fig. 2 A shows the magnetic disk 1 8 moved from the side of the material 2 to the rear. Fig. 2B shows a magnetic circle from the top of the material 2

8 ·>-A mechanism for punching by rotating the panel 1 with the rotating shaft 4 5 as the center.

 As shown in FIG. 2A, the magnetic disk 18 is held by a support bar 41 and is sealed via a vacuum sealing base 4 2 and a flange 4 3. Double tuner 4 1

4 4 is based on the 3K 4 9 with the sweep control including the source and travel distance measurement ¾δ = Support 4 1 is driven for a predetermined distance

 Further, in FIG. 2B, the magnetic disk 18 is held by a support rod 41 that is in contact with a rotating shaft 45, and is connected via a vacuum sealing flange 46. The motor 47 connected to the motor 47 is an insertion / extraction control device.

4 Use 9 to rotate the specified angle.

 The removal mechanism of these 2 is the same as the insertion position where the center axis of the objective lens 3 and the center axis of the magnetic disk 18 are aligned, and the retracted position outside the objective lens 3 area. The magnetic disk 1 8 is moved between

 Near the upper magnetic pole 15 of the objective lens, an optical-type child detector 19 is placed.

 Fig. 3 is a diagram for demonstrating the effect when the magnetic disk 1 8 is placed between the objective lens 3 and the material 8. Fig. 3 shows the field excitation as a constant value. The maximum value of the magnetic field strength on the optical axis is changed when the center hole diameter is changed. The maximum value of the magnetic field strength when there is no magnetic circle 1 8 is 10 In the example where the diameter of the center hole at 0% is smaller <the outer diameter is larger, and the magnetic field strength is increased, the force can be reduced to 1/3 or less. Since the outer diameter of the + V gap of the magnetic pole of the magnetic pole is 25 mm, the magnetic disk 18 is lower than the inner diameter of the lower magnetic pole (the outer diameter of the gap V). It is efficient to create a shape that overlaps with the pole

As explained with reference to Fig. 2, the magnetic disc 1 8 can be pulled out, so if the disc 1 8 is pulled out of the objective lens 3, the lens is attached. If high resolution observation that makes the best use of the characteristics of the image can be performed, the resolution will be slightly reduced, but it will still be possible to observe with high resolution and low power consumption. In the embodiment, WD of the objective lens = 3 m. Resolution with a distance of 15 mm between the magnetic disk 18 and the material 8 (the spot on the formula of the secondary wire) (Diameter) Degradation has been confirmed to be about 17 nm to 23 n <Second embodiment>

 The ability to explain the second implementation form using Figure 5B and Figure 6: A brief introduction to the technologies that will be offered to facilitate understanding. To be clarified

 Figure 4 shows an example of a common TTL detection system. Note that in Fig. 4, the partial force required for clarification is not shown.

 As shown in Fig. 4A, in order to increase the resolution of the electric microscope,

Since it is necessary to set the WD to several millimeters, it is common to place the EXB filter 11 and the electronic detector 1 2 above the upper magnetic pole: pole 15. . The smallest secondary electron that emerges from the sample is the E x B filter 1

1 can be used to efficiently introduce the detector 1 2 to the detector 1 2.

 However, the large backscattered electrons of the work are trapped by the magnetic field in the region where the magnetic field between the upper magnetic pole 15 and the sample 8 is strong, and rise in a spiral shape. The angle of the reflected electrons from the sample 8 escapes from the binding due to the magnetic field in the region where the magnetic field is weaker than the upper magnetic pole 15 above the upper magnetic pole 15. Depending on the angle, since it diverges like a group of orbitals 21 shown by the broken line, the incident light to the Ex B filter 11 is at a high angle from the sample 8 Of the backscattered electrons that are emitted, they are limited to those with relatively low energy

 >-These reflectors are converted to primary electrons 2 2 indicated by the solid line in the figure by the upper conversion pole 2 3 and detected by the action of the EXB filter 1 1 ¾5 In order to convert the backscattered electrons detected by 1 2 and having a diverging orbit into secondary elements 2 4 and 2 5, the lower conversion electrode 2 6 can be used. However, the range of backscattered electrons that collide with this downward-converting kame pole 26

 -Is also limited, the conversion efficiency and the uptake efficiency of the converted secondary electrons are not sufficient.

In addition, as shown in Fig. 4B, as a Τ Τ L-type detector, a cannula type is used. For detector A, using the detector 27, for the same reason as above, the reflector incident on the detector has a limited energy and emission angle. Therefore, there is not enough diversity in the surface information of the formula fee, and there is a hole through which the primary electron beam passes in the center. As a result, orbits rise without divergence-the efficiency of detecting secondary electrons decreases.

 In addition, as shown in Figure 5A, it may be possible to place the fulcrum type detection SB. 28 between the opposite lens 3 and the fee 8. By exploring these five configurations, it is possible to increase the solid angle of reflector incorporation to improve the detection efficiency and thus improve the detection efficiency. If the magnetic field strength is small enough to accommodate the primary i-element, or if it is a lens-type objective lens that does not leak because the magnetic field is on the charge side, As the backscattered electrons are bound to the field, they diverge at a wide angle even if they are emitted from the material, so the probability that the center hole of the electron detection 28 will be removed is small. Therefore, the detection efficiency of the next i-th child is very high.

 However, even if the configuration as shown in Fig. 5A is adopted, the strength of the magnetic field in the vicinity of the material is large in the series lens type, so that high resolution is achieved. If the WD is reduced <-, the magnetic field strength increases. Therefore, the reflector is also bound to the periphery of the optical axis by the magnetic field and becomes a converged orbit 29, which is detected electronically.

As soon as the center hole of 2 8 is easily removed, the detection efficiency of the primary electrons decreases, so that the detection efficiency of the secondary electrons can be improved. It is considered that the magnetic field strength in the vicinity of the material is weakened so that the reflected electrons emitted from the surface do not converge.

Fig. 5B is a diagram showing the configuration of the second embodiment, and shows the configuration for solving the deficiencies caused by the TT detection system in Fig. 4 and Fig. 5A. In other words, Fig. 5B shows the magnetic field intensity in the vicinity of the material so that the reflected electrons emitted from the material do not converge using the magnetic disk 18. It is a figure for explaining the configuration to weaken

 In this embodiment, as shown in FIG. 5B, a magnetic disk 18 and an electronic detection 3 1 are arranged between the objective lens 3 and the material 8 and the electronic detection is performed. Electron detection 3 1 with the objective lens side surface of output 31 as the magnetic disk 18 is thin and the WD can be smaller than MCP semiconductor detection. The magnetic disk 18 should be made of a high magnetic permeability material with a large initial permeability, such as iron-nickel alloy! The magnetic field between the magnetic disk 18 and the material 8 is reduced by inducing the magnetic field into the magnetic disk.

 Therefore, according to the configuration shown in Fig. 5B, the orbits 32 of the group of reflected electrons are not affected by the convergence of the magnetic field, so the reflected electrons are at the angle at which the power 8 is emitted. While keeping the degree, Hiro collides with detection 1. Therefore, since the electron that had been removed from the center hole is captured, the detection efficiency of backscattered electrons is improved, and in addition to the EXB filter using the TTL method: If the detection of primary electrons is performed by adding f outputs, it is possible to obtain the signals of the reflected electrons and the secondary electrons independently.

 In addition, in a semi-lens type objective lens, the reflected electrons emitted in a low angle (reflected electrons directed to other than the electron beam passage hole of the objective lens) are emitted. (Reflected electrons passing through five orbits that collide with the objective lens) are subjected to the bundling action of the objective lens as described above, and the objective lens is moved. Reflective electrons emitted at high angles because they pass through the trajectory.

It was difficult to discriminate detection of backscattered electrons emitted at low angle with (electron reflected electrons emitted toward the objective lens through-hole). 3 When the magnetic disk 18 with RX 1 can be inserted / removed, it is detected by discriminating between high-angle backscattered electrons and low-angle backscattered electrons. V,, or V ヽ is--If you want to select the direction selectively, as shown in Fig. 5B, the magnetic disk 1 8 is inserted into the objective lens 3 as shown in Fig. 5B. If you want to give priority to high-resolution measurement by placing it over the lens gap V In this case, it is better to make the effective lens main surface closer to the sample surface by removing the magnetic disk 18.

 Fig. 6 is a diagram for explaining the effect of reducing the magnetic field strength according to the second embodiment. Fig. 6 shows the excitation of the magnetic field on the sample of the primary electrons. As a condition, the change in the maximum value of the magnetic field strength on the sample surface when the diameter of the center hole is changed is shown. B z is the magnetic field component perpendicular to the sample,

B r is the magnetic field component parallel to the material. In addition, in Fig. 6, the maximum value of the magnetic field strength without the magnetic disk 18 was set to 100%.

 As shown in Fig. 6, the magnetic field strength can be reduced if the center hole diameter is reduced. In this example, the center hole diameter is reduced to less than 1/20. It is possible>

 In this embodiment, the magnetic field strength in this embodiment is B 0.

(Tester), Br can be reduced to about 0.05 5 T (Tester). Therefore, even when a sex specimen is used as a sample, the disturbance of the magnetic field on the sample is small, so high-resolution observation without changing the spot shape of the primary electron beam is possible. Furthermore, even if an element or medium having magnetization information is used as a sample, observation with less damage can be performed.

 When a magnetic material is not used as a sample, high-resolution observation is performed without inserting a magnetic material disk 18, and only when a magnetic material is used as a sample, the magnetic material disk 1 8 is used. You can also purchase. The mechanism for punching out the magnetic disk 18 is the same as that shown in Fig. 2, so the explanation here is omitted.

 In addition, if a means for automatically discriminating the type of material is provided, the magnetic disk 18 can be inserted / removed dynamically as shown in FIG. This is a diagram showing a configuration for automatically cutting a magnetic disk according to type J.

 Fig. 7 shows the configuration in which the magnetic disk 18 is automatically cut out.

The insertion / removal mechanism 4 8 and the insertion / removal control device 4 9 as shown in FIG.

M control amplifier 50, sample discrimination device 51, Gra Ph ica 1 U ser I 11 terfa C e (GUI) 5 2 and so on For example, many kinds of materials are being transported to SEM in a dynamic manner at semiconductor manufacturing sites. In some cases, it is necessary to manage the sample X with the use of K, which is commonly used, to determine the fee.

 ·-> And then use da to determine the type of charge

The computer 50, which is responsible for EM control, controls the exclusive control as well as setting up the electro-optical system suitable for the sample.

 4 Provide an operation signal to 9 to operate the punching mechanism to insert the magnetic disk 1 8.

 However, the fee discriminating device 51 is not limited to discriminating the fee using a saw, but it can be used for communication from a host computer for X management. , The shape of the material is a force mera, and the characteristics of the material are different from the type of material, such as X. For example, a hole in the material stand is HXed to transmit LED and laser light. It's okay to be

 -The exclusive control described above is the condition specified by the author in GUI 52, for example, the magnetic disk 18 cannot be inserted even for a specific sample. It is a control that gives priority to the condition that is positioned above the charge discriminating device 51 and discriminates that the charge is not magnetic. Magnetic disk 1

 -

It is possible to use 8 as the retraction position.

 <Third embodiment>

 FIG. 8 is a diagram showing the configuration of the third embodiment. In the third embodiment, it is necessary to reduce the magnetic field intensity on the sample so much. In this case, the child detection is not arranged between the objective lens and the material.If a magnetic disk is used, the magnetic field strength between the objective lens and the material is adjusted and the TTL method is used. The detection efficiency of the next i-child can be improved in the detection system.

As shown in Fig. 4 場合 when there is no m body disk 1 8, it reflects to 5 'Takeko's track 21 has a large loss due to the large track diverges when entering detection 27. As shown in Fig. 5B, the magnetic disk 18 reduces the magnetic field strength. If it passes too much, the reflector will be blocked by the magnetic disk 18, so the TTL method will not be detected.

 However, as shown in Fig. 3 and Fig. 6, if an appropriate magnetic field is applied to the optical axis to reduce the degree of convergence of the reflected electrons, the trajectory diverges above the magnetic pole of the objective lens. It is possible to create an excessive state, that is, the orbit of the backscattered electrons can be shown by the broken lines 3 and 3 shown in Fig. 8, and it is possible to detect the electron type of the circular type. Efficient in <2 7>

 Also, the backscattered electrons from which the center hole of the child detection is removed and the divergence of the original orbit are small. Next electron group 3 4 If the detection is done, EX filter: L 1 is placed. As a result, when it is introduced to electronic detection 1 2, the next i-element generated from charge 8 can be detected with high efficiency.

 <Fourth embodiment>

 Fig. 9 is a diagram showing the configuration of the fourth embodiment according to the present invention. O Fig. 9 controls the premium field between the magnetic disk 18 and the objective lens 3. The magnetic disk 1 8 and the electric field control electrode 3 5 are electrically connected to each other, and the magnetic disk 1 is provided with a field control electrode 3 5 and a voltage applying means 3 6.

子 を 加 速 し て 色収差 を 減 ら し よ て 分解能 を 上 げ る た め の も の で あ り 電圧 印加手段 3 8 も ¾ 料 料台 に 電 圧 を 掛 け て 分解能 を i¾ め る た め に設 け ら れた も の で あ る な お 、 二次 的 な S子 の 検 出 系 は 図 8 と 同 様 の の を 用 い る A voltage can be applied to 8 and the objective lens 3 is electrically insulated from the upper magnetic pole 15 and the material 8 or <is a means to apply pressure to the material 13 The electric field control pole 3 5 is equipped with a charged sample, and the i-pressure applying means when such a material has an action < The voltage application means 3 7 is a magnetic circuit that has the effect of preventing the beam K fow by making the electric field in the vicinity of the material parallel to the electric field created in 3 7 and 3 8 Apply voltage to

The voltage application means 3 8 is also used to increase the resolution by increasing the resolution by accelerating the element and reducing the chromatic aberration. The secondary S-child detection system is the same as that shown in Fig. 8 and is used to increase the resolution by applying pressure.

 With this configuration, the next child is accelerated above the objective lens 3.

 >-Can be slowed down or slowed down, and only the magnetic disk 18 can control the secondary electron trajectory by the action of the near field. Finer orbit control is possible.

 <Fifth embodiment>

 Fig. 10 shows the configuration of the fifth embodiment according to the present invention. In the fifth embodiment, as shown in FIG. 10, the shape is basically the same as that shown in FIG. 9, but the upper magnetic pole 15 insulated from the objective lens 3 is connected to the upper magnetic pole 15. Instead of applying a voltage, near the magnetic pole-the purpose is to improve the detection efficiency by changing the trajectory of the next child. 9 and voltage applying means 40, that is, a magnetic disk 1

8-The next electron trajectory can be changed, but the trajectory control electrode 39 and voltage applying means 40 compensate the changed trajectory (orbit

 You can increase or decrease the size of-. Even with the configuration of Fig. 10, the same effect as the implementation m in Fig. 9 can be obtained.

 <Sixth embodiment>

In the sixth embodiment, which is intended for observing a large insulating sample such as a reticule, according to this embodiment, the energy of the incident electron beam is the same. AEI (After Etch In ns Pecti On) and AD: I (After De V e 1 opment I nspetion) are applied. For the reticle, the device id configuration that enables stable length measurement using a scanning electron microscope is shown in the fourth or fifth embodiment. It is possible to use the one (shown in Fig. 9 or Fig. 10) However, in the embodiment of 6, the diameter of the core wire hole of the magnetic disk 18 is larger than the diameter of the core wire hole of the S-field control pole 35. The hole diameter of the disk 18 is 5 mm or more, and the hole diameter of the field control electrode 35 is 1 mm. As will be described later, the hole diameter of the magnetic disk 18 is reduced. This is because the effect of the magnetic field shielding is so large that the emitted electrons do not return to the vicinity of the irradiation point and the effect of the band suppression is reduced. Ru

 In this embodiment, it is generated from fee 8-the generation efficiency of secondary electrons is 1 or less

 The energy of the child wire irradiated to the fee 8 to be on the Ai is usually the same as that of the child wire, although there is a difference depending on the type of fee to determine the HX. Gi is below 1 keV, and the surface of the material is short of electrons, resulting in a positive ηt electric state.

 The field control electrode 35 is made of a flat plate with no protrusions.

3 5 Use the voltage application means voltage 3 6 and 3 8 for the stage 1 3 and apply the pressure to control the surface potential to control the potential gradient on the surface of the insulating material. Can reduce the band m at the time of beam irradiation; the electric field control electrode 3 5 stage 1 the potential of the magnetic disk 1 8 is Set the same potential

This and the implementation of this book «&

 Depending on the configuration, in addition to the band suppression action by the electric field control pole 35 described in H'i, the effect of charging suppression by the magnetic field shielding action of the magnetic circle 18 is also added. It will be possible to further suppress ff electricity.

 Fig. 11 is a conceptual diagram of positive band suppression by magnetic field shielding action. In this embodiment ■, it is generated from charge 8-the generation efficiency of secondary electrons is 1 or more. The surface of the metal 8 has a positive zone 5 3 formed on the surface.

Suppression is achieved on sample 8 by the magnetic field shielding effect of sex body disk 1 8 which is made possible by positively returning the pa child released from fee 8 to fee 8. The field distribution of the magnetic field changes As a result, the orbits of the emitters 5 4 are changed, and the electrons emitted from the charge 8 can easily return to the formula fee. <The load emitter that can be loaded returns to the charge. The normal zone 53 formed in the material 8 is suppressed.

Explains the principle that the emitted electrons easily return to the material 8 due to the magnetic field shielding action at the material normal direction component on the material 8 with the magnetic disk 1 8 The maximum intensity of the magnetic field B z and the field B r of the water component in the direction of water is reduced to 5 as shown in Fig. 6 compared to the case where the magnetic circle 18 is not arranged, Figure 12 shows an example of the change in the magnetic distribution near the optical axis in the vicinity of the optical axis because the magnetic field that contributes is near the optical axis. R [m] is the off-axis distance from the optical axis in Fig. _T 1 2, the vertical axis of A B is B Β r, respectively, and the magnetic disk 1 8 is placed. As long as it is smaller than the vicinity of the optical axis, B is large and the flying of the ejector emitted by the decrease in the intensity of B z is large. Near the optical axis The π-rench force acting on the emitter due to the increasing strength of Βr is that the vector component in the downward direction (the direction of the feed) becomes larger. The emitted electrons can easily return to the price direction.

 If the hole diameter of the core wire through-hole opened in the magnetic circle 18 is changed, the value of Βr / Bz on the material will change and will be emitted along with it. Figure 13 shows an example of the amount of return of the landing point position of the B r B z emitter as the hole diameter changes as the landing point return ft of the child also changes. The disc 18 is lev, and the combined value is 100%. □ The objective lens is energized as a condition that the next lens converges on the fee.

From Fig. 13 it can be seen that as the hole diameter of the sexoid disk 18 decreases, the return amount of emitted electrons increases, but at the same time the landing distance becomes larger. W1 As stated 5 Magnetic disk: 1; 8 hole diameter is too small >-When the effect of magnetic shielding is less than B and B z is less, the emitter does not return to the vicinity of the irradiation point, and this is effective in suppressing the positive charge in the irradiation area. Reduced

 The optimal return amount of the emitter depends on the observation object and light conditions, but the return position g varies, but these adjustments can be made by adjusting the hole diameter of the magnetic disk 18 The f is the most weekly according to the situation.

 It is important to set the hole diameter. However, in this example, if the hole diameter is 16 m or more, the effect of effective magnetic field shielding is almost < Therefore, the hole diameter Φ i of the magnetic material circle 1 8 is hatched within the range of 5 mm <Φ i-1 6, and the thickness of the magnetic material disk 1 8 is 0 5 m.

 As an effective method for selecting the appropriate hole diameter, a plurality of magnetic discs 18 having different hole diameters are placed in the inside of the specimen chamber 2 of the microscopic microscope, depending on the situation. By arranging individual sex disks 1 8 between the electric field control electrode 3 5 and the material 8, a wide variety of observation materials and optical conditions can be conceived. The magnetic disk 18 is parallel to the objective lens 9 and the material 8 and passes through the hole through which the primary electron beam passes through the center of the pole hole of the objective lens 9. Arranged to match the axis

 Fig. 14 shows the configuration of the exchange mechanism 55 of the magnetic disk 1 8, which is a diagram similar to the disk punching mechanism 4 8 shown in Fig. 2B. However, the magnetic disk support bar 4 1 can be moved up and down.The magnetic disk support bar 4 1 capable of rotating up and down is provided in the material 2 by the magnetic disk support bar 4 1. A desired magnetic circle 18 can be taken out from a plurality of magnetic discs 56 having different inner diameters. 1 8 is placed at a predetermined position by an exchange control device 5 7 including a source and a moving distance measuring device.

In order to describe how to select the magnetic circle 18 with the best hole diameter for a given fee and optical conditions, use different image acquisition conditions. What is the acquisition condition for acquiring images? The condition of the band changes greatly.The band elder brother changes the band condition by changing the scanning speed of the secondary electron beam, the number of accumulated images, etc. Although the conditions for large <change are different, in the state where the charging is suppressed, even if the image acquisition conditions are changed, the difference in the image is small, but the band is remarkable. The change in the band situation is also large <The amount of secondary electron emission also changes greatly, so the difference in the images obtained becomes large, so the images can be captured under different image acquisition conditions. Acquire and calculate the difference in luminance for each pixel of the two images. The total value of the entire image of the luminance difference value in each pixel, where charging is suppressed! The magnetic material whose total difference is the smallest among the multiple magnetic discs 56 with different hole diameters provided in the material 2 to be reduced. The body disk 1 8 is selected, and the magnetic disk 1 8 having the hole diameter is replaced with the body disk exchange mechanism 5

5 should be placed in place

 It is also possible to find a condition that suppresses electrification by obtaining a luminance histogram, so that the resist coated with resist is applied. As an example, the scanning region of the electron beam is set to the chapter β that is irradiated only with the register 、. ■-It is easy to judge whether electricity is suppressed, and the S-shaped image of the register part, which is the reason for this, has different hole diameters. Assuming that the band is not generated by acquiring the luminance histogram by obtaining the sexoid disk 18 in the placed state,

-The next mi child emission rate does not depend on the location-so the histogram becomes a single peak and the shape becomes steep and the band is notable. As a result of the change in the primary electron emission rate due to the influence of the band, a new peak is generated in the His-gram or the shape of the peak becomes dull. Therefore, it is shown that the number of pixels in the histogram is smaller <and the sharper the shape of the peak, the more the charge is suppressed. Comparing the shape of the His / Gram has the optimum hole diameter for band suppression. Select the magnetic disk 1 8 and replace the magnetic disk 1 8 with the magnetic disk.

 · ·

It is possible to place it at a predetermined position by the change mechanism 5 5 o

 Furthermore, the return and return positions of the ejector can be adjusted by adjusting the position of the magnetic disk 18. O The magnetic disk 18 is connected to the objective lens 9 Parallel to B-type material 8 and-The hole through which the next electron beam passes is placed in the center of the magnetic pole of the objective lens 9-the hole-this position is adjusted. Alignment refers to the upward and downward position adjustment between the electric field control electrode 35 and the δ-type material 8, which is realized by the magnetic disk exchanging mechanism 55 with the upper and lower moving mechanisms. Possible to suppress charging by the following method: After placing the magnetic disk 1 8 with a hole diameter of k weeks, the magnetic disk 1 8 is further replaced with the magnetic disk exchange mechanism 5 5 The electric power is not changed while going up and down.

The position where the band is restrained can be found in the following steps. O Due to the above work, the hole diameter of the m-shaped body disk 18 and the upward and downward position and the electrostatic charge are reduced.

The upper and lower movement range of the magnetic disk 1 8 set to the optimum state is the state where the lower surface of the electric field control electrode 3 5 is in contact with the upper surface of the magnetic disk 1 8 and is the moving origin. The magnetic disk 1 8 has a lower surface of 0 5 mm from the surface of the material 8 ο 0 5 mm is the pressure application means 3 6 and 3 In the case where the magnetic disk does not operate at the same time, the electric field strength between the lower surface of the magnetic disk 1 8 and the surface of the ρ \ material 8 is large, and there is a possibility that lightning will occur between the two. Magnetic material that can be used for safety reasons

 -Moving the disk 18 downwards has the same effect as increasing the hole diameter of the magnetic disk 18, but it is not necessary to calculate the luminance histogram or cut the hole diameter. Replacement control, etc. Calculations and controls necessary for the above processing are executed by a control device (not shown).

In addition, the energy of the objective lens is large for α, which has a large amount of random energy (the number of sub-wires when reaching the S charge). <Increased radial force of emitted electrons S / J><Landing energy or objective lenght because the landing distance becomes shorter More specifically, it is considered to reduce the hole diameter of the disk when compared to when the excitation current is lower than when the excitation current is low. If the ring energy is less than the specified value, give priority to the landing distance, increase the hole diameter, and the landing energy is larger than the specified value.

In some cases, it may be possible to reduce the hole diameter by returning the electrons first.

 However, since the size of the hole diameter that is correct weekly varies depending on other equipment conditions and the composition of the materials, etc., the above prescribed value should be obtained in advance according to the installation conditions.

<I want this □

 In addition, if a magnetic disk that is inappropriate for the equipment conditions and the composition of the material is used, there is a possibility that the positive band β may be excessively shelled. -The next element is pulled back into the charge, and the amount of detectable elements is reduced, so the image becomes smaller. O This principle is used to increase the image quality. The amount of light and dark electrons detected in a good image can be controlled by detecting that the detection of electrons or m has decreased and switching the hole diameter to 7L. This monitor is controlled by a control unit that is not shown in the figure, and it is controlled by switching the hole diameter so that the degree of light and darkness of the image and the amount of electronic detection change beyond the expected values. If the hole diameter is switched and the image does not return to the specified state, other factors of image fluctuation may be considered. Therefore> It is good to generate an error message. Furthermore, the hole diameter is changed according to the size of the landing energy. In this case, the Z movement stage (Z is the optical axis of the electron beam) can be changed by changing the hole diameter according to the size of D. Direction), the hole diameter should be switched according to the height information of the Z-motion stage. In the case of a device equipped with the Z sensor to be measured, it is considered that the hole diameter can be switched by d, depending on the height of the if¾ fee detected by the Z sensor.

X. <Summary>

 In the lens and lens type, the objective lens 3 is moved to the fee side in order to actively leak the field onto the fee 8 and bring the lens owner closer to the ceremony fee. It is normal to have an open magnetic pole gap, and the magnetic field for converging the primary electron beam that irradiates the material has the strongest magnetic pole. The field leaks from the gap and is divided on the optical axis that coincides with the central axis of the objective lens, so it is compared with the magnetic field at the magnetic pole gap V. Since the intensity is less than 0, the objective lens near the magnetic pole gap is used to increase the magnetic field intensity on the optical axis. 3 is dealt with by arranging an independent magnetic disk 1 8 so that the center axis and optical axis of the disk coincide with each other. 0

 The magnetic circle ψ. 1 8 is placed at a distance from the objective lens 3 in order to increase the magnetic resistance with the objective lens 3. The leakage magnetic field from the magnetic pole is guided to the physical disk 18, and if there is no magnetic disk 18, the efficiency is higher than the formation of an unnecessary magnetic field in the space. The reason why the shape of the disk is not discriminable to increase the magnetic field strength on the optical axis is that it uses the magnetic field of the axisymmetric objective lens asymmetry. Ο

 Gru the magnetic disk 1 8 against the objective lens 3

 Make space

It is necessary to avoid magnetic saturation by introducing an unnecessarily strong magnetic field, and a sensor that does not have a magnetic disk 18 is an incline lens type. The characteristic designed to be the most as an object lens of the lens was <to change <, and there was a capital π to improve the field strength on the optical axis. In particular, the thickness of the disk is reduced in order to incorporate a magnetic field attenuated in the air independently from the objective lens 3 into the magnetic disk 18. Because the magnetic field does not leak from the surface of the disk 8 on the disk, the effect of shielding the leakage magnetic field on the material-is very large. It is also a hand to solve the second and third issues 0 The second problem is to improve the detection efficiency of the primary electrons generated from the formula fee 8. According to this embodiment, it is particularly easy to detect the backscattered electrons. Depending on the operating conditions of the optical system, secondary electrons and reflected electrons can be separated and detected.

 This makes it possible to design a detection that is specific to each type of electron, so that the detection rate of the device can be greatly improved. The

 Specifically, in the case where the electron detection is arranged between the objective lens 3 and the material 8 in order to detect the reflected electrons, the trajectory is constrained by the magnetic field and the orbit is converged. In order to prevent the backscattered electrons from being removed from the hole in the center of the electron detector, the electrical detector and S-type material The magnetic field strength between them should be reduced. In other words, using the magnetic disk marked η, the leakage magnetic field from the objective lens magnetic pole is guided to the magnetic disk so that the orbit of the reflected electrons is strong and does not converge. It is possible to reduce the magnetic field strength

 Therefore, the electronic detection 3 1 is placed facing the family 8 and the detection is performed.

 When the magnetic disk 18 is placed between 1 and the objective lens 3, the reflected electrons are confined to the field and the velocity and angle emitted from the material are maintained. In addition, since it is incident on the detection 31 in a wide orbit, it is possible to detect without any loss of quantity. Reflection with a small elevation angle of 8 forces Since the electron yield is increased, it is possible to detect the concavity / convexity information on the surface of the material and the error in the structure of the material more prominently. The function of the case 3 can be improved.

 In this process, the child detection 3 1 and the magnetic disk 1 8 are separated separately.

Since it becomes difficult to reduce the WD due to the waste caused by the BX, the surface itself on the objective lens side of the electronic detection 31 may be formed by the magnetic disk.ヽ Τ L method using detection specializing in detection of secondary electrons as the configuration of the electron detection system of this microscope It is possible to detect secondary electrons with the center hole of the electron detection 3 1 placed between the objective lens 3 and the material 8 being removed by combining Get out. In addition, the sensitivity of the energy detected by the electronic detector 3 1 placed between the objective lens 3 and the base 8 is higher than that of the energy that the next electron is usually in. For example, if it is more than 100 eV, it will be possible to detect backscattered electrons and primary elements.

 In addition, the magnetic field intensity in the vicinity of the material 8 is adjusted using the body circle 18

(Shielding the magnetic field) weakens the convergence of the reflector between the objective lens 3 and the material 8, and the reflection in the region where the magnetic strength is <<above the magnetic pole of the objective lens. The divergence range of the child is narrowed and the loss caused by collision with the objective lens 3 or a member in the vicinity of the magnetic pole can be achieved.

 Therefore, even in the τΤL method, a detection efficiency specialized for detection of reflected electrons and primary electrons can be used to obtain a high detection efficiency.

 The third problem is to provide a child microscope capable of observing materials in which the original characteristics may be impaired by the magnetic field. For the subject, as stated, the first issue and the first issue.

 It is difficult to reduce the magnetic field strength on the surface of the material 8 by using the magnetic field shielding effect of the magnetic disk 1 8 which is the solution to the problem 2).

 More specifically, the magnetic disk 18 has a high initial permeability such as iron and nickel nickel alloy, and the center of the disk using a high permeability material. The diameter of the hole is small <as-

(It is larger than the scan range of the child beam) If the shielding effect of the magnetic field between the magnetic disk 18 and the material 8 is increased, as described above, The peak of the magnetic field strength on the optical axis increases due to the increased utilization efficiency of the magnetic field.

In addition, if the outer diameter of the magnetic circle 18 is large, the effect similar to the effect of reducing the diameter of the center hole can be obtained. The gap between the magnetic pole and the magnetic path that forms the outer diameter of the gap of the objective lens magnetic path gap is smaller than A. Establish The effect of the disk becomes larger when it is larger than 1 mm. The thickness of the disk is less than 1 mm in consideration of WD magnetic saturation, etc. A sufficient shielding effect can be obtained.

 Furthermore, if the distance between the disk 18 and the 5 formula fee 8 is increased, the shielding effect is increased. When the practical distance is selected to be about 1.5 mm, the magnetic field excitation condition for focusing the primary electron beam on the sample 8 is less than that for the case where the disk is not present. Formula fee 8 The magnetic field component level and deviation straight and parallel to the surface can be reduced to 1/20 or less.

 With this configuration, S¾ fee £! It is possible to reduce the upper magnetic field, which is easily damaged by the magnetic field. 8 The observation of the magnetic disk 1 8 and the 8 Because the magnetic field of the magnetic field does not affect the orbit of the backscattered electrons, the detection efficiency can be maximized by solving the first problem.

 On the other hand, the reduction rate of the magnetic field strength on the sample should be about 1/5, and the reflected electron is weak. The magnetic field strength that is subject to the convergence effect is always between the objective lens 3 and the material 8 There is no need to place an electronic detector in the τ TL method, and if a magnetic disk is used in the τ TL method, the detection efficiency can be improved.

 In this case, the outer diameter of the magnetic disk 18 (for example, the lower pole

 Degree) and thickness (considering m-saturation), diameter of the center hole (larger than the scan range of the child beam, necessary to change the trajectory of the secondary) If the size of the hole is smaller than the limit of the hole size enough to create a magnetic field, the shielding effect of the magnetic field will remain intact and the objective lens will remain intact. 3 and charge 8 1 day] The primary magnetic orbit generated from charge 8 should be controlled by adjusting the magnetic field strength and minute generated. In addition, in the detection system V of the TT method, a detector 1 2 that mainly detects secondary-¾en and a detector that mainly detects reflected electrons ¾ 2

7 and at least one at a time according to the arrival point of the secondary electrons generated from the materials, depending on the energy of the electrons. Efficient detection is possible

 The relationship between the shape of the magnetic disk 18 and the field and the child trajectory * The relationship between the strength of the magnetic field and the magnetic field can be analyzed by the computer simulation 3 In the region where the magnetic field strength above the fe pole of objective lens 3 decreases, the trajectory can be changed in line with the next child's energy. And can

 In other words, depending on the case, a voltage may be applied to the magnetic path of the objective lens 3 and the material 8, or <may be applied to the electrodes constituting the electron optical system. 18 According to the shape of 8 – the size of the energy is as small as the next electron, and the electron (mainly 50 eV or less) is the widening of the orbit above the pole of the objective lens 3. It is possible to suppress the drift and adjust the degree of spread of the orbit by the number of energetic electrons (mainly a number of 1 · 0 0 eV or more). wear

 For example:-Use the magnetic field and the mj field as the detection of secondary electrons 1-2-Without affecting the trajectory of the secondary electron beam, EXB finalizer capable of deflecting only the lower element: L: 1 and: Detection combined with the secondary electron multiplication function and detection of reflected electrons 27 The detection efficiency is improved by locating a mirror type MCP or semiconductor detector on the optical axis and detecting by direct incidence of the reflecting element. It is possible to

 The fourth topic is the observation of insulators using an electron microscope, and the suppression of the band due to the shielding of the magnetic field makes the insulation material particularly intense. High resolution and high reproducibility <reproducible <Reproducible microscope microscope can be provided

When measuring charged materials such as reticles using a scanning microscope, image damage occurs due to the effects of charging, and measurement with high λ-η degrees is possible. In the current reticle measurement S Ε, which is impossible, the incident energy of the primary electron beam is set to 5 so that the primary electron emission rate is 1 or more. The surface of the sample is placed in a regular band, and the surface position distribution is controlled by the shape of the flat plate electrode and sample table placed between the sample surface and the objective lens. Reticle measurement is possible. However, however, an incident beam such as a lenticule coated with lens or soot is applied. For materials with large band changes that depended on the energy level, charging was not completely eliminated.

 In the present invention, a magnetic disk is placed under the objective lens and the electric field control electrode to change the magnetic field distribution generated by the objective lens and to emit electrons generated from the three materials. By returning the sample to the sample, the positively charged sites are neutralized and the charge is further suppressed. By shielding the magnetic field, the magnetic field in the vicinity of the surface of the material changes, and ≠. Electrons easily return to the surface of the material. O The magnetic field distribution on the sample depends on the distribution of the magnetic disk. Directional component magnetic field

The peak intensity decreases in the magnetic field B r and 'b' of the component in the direction of B z and feed water.

The intensity reduction of BZ increases the range of m-elements emitted at a low angle close to the horizontal direction of the specimen, especially in the vicinity of the optical axis, and the emission element is increased by Br. It will be easier to return to the price direction.

 In the state where the magnetic disk is arranged, the return amount of the emitted electrons may be increased up to 3 times as much as when the magnetic disk is M. It is possible to increase the positive band suppression effect o Optimum return amount and wearing amount

 -The point varies depending on the sample to be viewed, but they can be changed depending on the hole diameter and position of the magnetic disk. It is an important patenting item of the present invention that it is possible to select the optimal conditions for suppression and observe images.

 The power s, which is not explicitly stated in the examples, is the power consumption, such as the acceleration voltage or the height of the material to be observed. Changes. The change in the convergence condition results in a change in the optical multiplication factor of S E M, resulting in a change in the irradiation region of electrons on the material.

In EM, the 3S la. Built-in simulation 3 Calculate the sample length and the optical multiplication factor from the parametric sensor and the formula for calculating the pre-measured optical magnification and the change in the current value of the objective lens. As a result, the amount of excitation applied to the deflector is changed to control the irradiation area to be constant.

 In this embodiment, the magnetic disk is removed. The magnetic disk and the change in the insertion position cause a change in the magnetic field and the field. Irradiation area is the same regardless of the disk usage conditions by using the parameter table and calculation formula considering the presence / absence of the magnetic disk and the shape position, and the current value of the objective lens. Needless to say, excitation bias control with a certain bias is performed.

 As described above, according to this embodiment, the same technology that can be realized at a very low cost with a simple configuration for reducing power consumption and improving detection efficiency is used. With this, it is possible to reduce the damage caused by high-resolution observation of magnetic samples and the magnetic field of information-bearing materials.In addition, primary electrons and reflected electrons are independently detected. X. It is possible to add X. In addition, high resolution and accurate reproducibility <reproducibility of a resist sample with a resist applied especially to an insulating material sample becomes possible.

Claims

Of request 1. A scanning electron microscope that irradiates a sample with an electron beam and scans the sample to detect the sample force and secondary electrons including secondary electrons or reflected electrons. So,  An electron source that generates electrons,  A group of lenses that use the electrons emitted from this electron source to form an electron beam and then expand or contract this electron beam electronically;  A deflector for scanning the electron beam;  A magnetic field type objective lens having an upper magnetic pole and a lower magnetic pole for converging the electron beam on the sample;  A detection means for detecting secondary electrons generated when the electron beam is incident on the sample, and is disposed closer to the electron source than the magnetic pole of the objective lens. The first detector,  A disk-shaped magnetic body disposed between the objective lens and the sample and having an electron beam passage hole in the center; A scanning electron microscope characterized by comprising:  In addition, a second detector for detecting secondary electrons emitted from the sample is provided.  The scanning electron microscope according to claim 1, wherein the second detector is formed on the sample-facing surface of the disk-shaped magnetic body. .  3. The scanning electron microscope according to claim 1, further comprising a disk insertion / removal mechanism that allows the disk-shaped magnetic body to be inserted / removed.  4. In addition, a sample discrimination means for discriminating the type of the sample, Depending on the result of the sample discrimination, the disc-shaped magnetic material is inserted between the objective lens and the sample and extracted from the sample lens. Claim 3 characterized by comprising an insertion / extraction control means for controlling. Scanning electron microscope described in  (5) A scanning electron microscope as set forth in item (1), further comprising a disk exchanging mechanism capable of exchanging a disk-shaped sex body with another sexoid disk.  6 In addition, the exchangeable magnetic disk described in claim 5 is provided with at least two exchangeable magnetic disks, and the running type electron described in claim 5 is characterized. Microscope  7 In addition, the magnetic circles described in claim 6 are characterized in that either the inner diameter or the outer diameter or both dimensions are different. Scanning microscope described in 5 ο  8) A scanning electron microscope as set forth in Claim 1, characterized in that the outer diameter of the disc-shaped body is larger than the inner diameter of the lower magnetic pole constituting the objective lens.  9 Furthermore, voltage is applied to the disc-shaped body «3 ·  A scanning m-microscope as described in Claim 1 characterized by having a ¾ pressure application hand St applied. Further, it is arranged between the upper magnetic pole constituting the objective lens and the detection L tl of the second lens L. The second detection for detecting the next electron is performed. Preparation  (2) The second detection is a scanning e-microscope according to claim 1, characterized in that it has an aluminum shape and has an electron beam passage hole at its center.  1 1 In addition, it is arranged between the first detection and the second detection, and is passed through the electron beam passage hole of the second detection m. The scanning electron microscope according to Claim 10 characterized in that it has a bias to introduce the element into the first detection SB. 1 2 Further, the traveling electron microscope according to claim 10, further comprising a first voltage applying means for applying a voltage to the circular body. 1 3 In addition, there are two voltage application means for applying a voltage to the upper magnetic pole of the objective lens.  Apply voltage to the sample stage to place the sample or the 5 formula 3 β-pressure applying means, X. Scanning electron m microscope according to claim 12 characterized by the fact that it is characterized. 1 4 In addition, the pole placed near the top pole of the sd objective lens And the location ^m,  A second voltage applying means for applying pressure to the recording electrode;  ,  A voltage is applied to the sample table for placing the sample or material. 3 i pressure application hand, and A scanning electron microscope as set forth in claim 12, characterized by comprising: 1 5 primary electron beam power ^s field or the magnetic field to that region transmission, to come and Oh Ru have the its is found both distribution changes,刖Kihen direction on the charge of the primary electron beam So that the scanning area determined by the means does not change.  , α. The feature is that it has a function to adjust the control amount in the direction U. Scanning electron microscope described in 4 ο  1 6 Scanning type that irradiates the sample with electron beam and scans this sample to detect secondary electrons from the sample. With a child microscope,  An electron source that generates electrons,  A group of lenses that form an electron beam using the electrons emitted from this source and expand or contract this i-beam in an optical manner; The bias that drives the electron beam ^: ^  A magnetic field type objective lens that has an upper magnetic pole and a lower magnetic pole and focuses the electron beam on the material; A detection means for detecting primary electrons generated when the core beam is incident on the material, and is disposed on the magnetic pole Si element source side of the objective lens. 1 detector, A disk-shaped magnetic body disposed between the objective lens and the recording material and having a core wire hole in the center;  Note that the target is between the upper magnetic pole constituting the objective lens and the first detection. The second detection that detects the next child that is placed  t- Detecting the whistle 2 placed between the first detection of the IU and the second detection of the memorandum Whistle 2 ¾5 SB. Bias for leading to the first detection SB. Prepare  The second detector is a scanning electron microscope characterized in that it has an annular shape and has a strand passage hole at its center.  1 7 A trajectory equipped with an electron source and a field-type objective lens that focuses the electron beam emitted from the electron source and a detector that detects the electron emitted from the material In the microscope  The objective lens is configured to leak a leakage magnetic field for focusing the electron beam toward the recording side.  Between the objective lens and the material, there is provided a moving mechanism that holds the magnetic material that can suppress the arrival of the magnetic material of the IJ memory leakage. Run type mm-child microscope  1 8 In claim 1 7  (2) A traveling electron microscope characterized in that the recording material is provided with an open P for passing the in-wire.  1 9 In Claim 1 8  The IU movement mechanism is characterized by holding multiple transcribed Ps of different sizes, and switching the opening P of the line 7L by the movement of the movement mechanism. Vertical electron microscope