JP4963366B2 - Vacuum chamber apparatus, electrostatic latent image forming apparatus, and electrostatic latent image measuring apparatus - Google Patents

Description

  The present invention relates to a vacuum chamber device, an electrostatic latent image forming device, and an electrostatic latent image measuring device, and more particularly, to a vacuum chamber device, an electrostatic latent image forming device, and an electrostatic latent image measuring device in which a sample stage can be easily attached. .

  In order to obtain an output image, an electrophotographic image forming apparatus such as a copying machine or a laser printer normally performs the following process. The configuration of an electrophotographic apparatus that executes each process and obtains an output image is shown in FIG.

1. Charging: The electrophotographic photosensitive member (photosensitive member) is uniformly charged.
2. Exposure: The charged photoreceptor is irradiated with light to partially release charges corresponding to the image to form an electrostatic latent image.
3. Development: A visible image is formed on the electrostatic latent image with charged fine particles (hereinafter, toner).
4). Transfer: Move the toner image to paper or other transfer material.
5. Fixing: The toner forming the transfer image is fused to fix the image on the transfer material.
6). Cleaning: Cleans residual toner on the photoreceptor.
7). Static elimination: Removes residual charge on the photoreceptor.

  The process factor and process quality in each of the above steps greatly affect the final output image quality. For this reason, in order to obtain a higher quality image, it is necessary to improve the process quality of each process. In particular, evaluating the quality of the electrostatic latent image is extremely important for obtaining a high quality image. is there.

Incidentally, the writing optical system used in the exposure process is optimized and designed as a beam spot diameter on the surface of the photoreceptor. That is, such a design is performed even though it should be designed so as to form an optimal electrostatic latent image on the photoreceptor that directly affects the behavior of toner particles. Not a translation. In addition, a clear mechanism for converting exposure energy into an electrostatic latent image has not been established.
Therefore, if the information obtained from the electrostatic latent image can be taken into the optical system design, it is expected that the image quality can be further improved and the image forming apparatus can be designed at a low cost.

  However, it is extremely difficult to measure an electrostatic latent image, and it is impossible to measure at all in actual use. A well-known method for measuring an electrostatic latent image is to bring a sensor head such as a cantilever close to a sample having a potential distribution, and at that time the electrostatic attraction or induction that occurs as an interaction between the electrostatic latent image and the cantilever. In this method, a current is measured and converted into a potential distribution. The electrostatic attraction type is commercially available as SPM (Scanning probe microscope), and the induced current type is disclosed in Patent Literature 1 and Patent Literature 2.

In order to use these methods, it is necessary to bring the sensor head close to the sample. For example, in order to obtain a spatial resolution of 10 μm, the distance between the sensor and the sample needs to be 10 μm or less.
Under these conditions,
○ Absolute distance measurement is required.
○ Measurement takes time, during which the state of the latent image changes.
○ Discharge and adsorption occur.
○ The sensor itself disturbs the magnetic field.
Even if it can be applied to other uses, an electrostatic latent image cannot be measured in actual use.

For this reason, as a practical measurement method, a charge is applied to the toner, which is a colored fine powder, and the toner is attached to the photosensitive member by a Coulomb force acting between the charged toner and the electrostatic latent image, and developed (electrostatic A method is generally used in which a latent image is visualized) and the toner image is transferred to paper or tape.
However, since this method has undergone development and transfer processes, the electrostatic latent image itself is not measured.

On the other hand, a method for measuring a potential pattern using an electron beam is known. This is a technique that has already been put to practical use for LSI failure analysis. However, this measurement method is applicable only when the sample is a conductor, and cannot be applied when a dielectric such as a photoreceptor is the object to be measured.
This is because if the object to be measured is a conductor, the potential distribution can be maintained for a long time by passing a constant current through the conductor, and the potential amount is at most a narrow range of 0 to 5 V. This is because it does not occur. Furthermore, if the object to be measured is a conductor, the potential state does not change by irradiation with an electron beam.

As a method for observing an electrostatic latent image using an electron beam, there is a method disclosed in Patent Document 3.
Japanese Patent No. 3009179 JP-A-11-184188 Japanese Patent Laid-Open No. 03-049143

However, in the method disclosed in Patent Document 3, the sample is limited to an LSI-sized chip or an electrostatic latent image that can be recorded / held. That is, it is impossible to measure a normal photoconductor that causes dark decay.
Since a normal dielectric can hold a charge semi-permanently, even if it takes a long time after forming a charge distribution, it does not affect the measurement result. However, since the resistance value is not infinite in the case of the photoconductor, dark decay occurs as described above, and the surface potential decreases with time. Even in the dark room, the time for which the photoconductor can hold the electric charge is at most several tens of seconds. Therefore, even if an attempt is made to observe with an electron microscope (SEM) after charging and exposure, the electrostatic latent image disappears in the preparation stage.

  Furthermore, the photoreceptor sample used in the electrophotographic process generally has a cylindrical shape, and it is desired that the electrostatic latent image distribution generated on the cylindrical photoreceptor is measured at a high resolution in a nondestructive manner. Even if the charge distribution forming means is the same, the electrostatic latent image changes due to the deterioration of the photoreceptor over time. For this reason, it is also desired to evaluate the variation of the electrostatic latent image over time.

The present invention has been made in view of such problems, and an object of the present invention is to provide an electrostatic latent image measuring apparatus capable of measuring an electrostatic latent image within a short time after the latent image is formed.
It is also intended to facilitate attachment / detachment of the vacuum sample stage unit to / from the vacuum chamber and to improve workability outside the chamber for setting the installation conditions of the photoconductor as the test object and setting the exposure optical system. And

In order to achieve the above object, according to a first aspect of the present invention, there is provided a vacuum chamber apparatus including a sample stage that holds a sample and is accommodated in the vacuum chamber through an opening on one side and movable in an arbitrary direction. there are, on the outer wall of the vacuum chamber, the stage and the sample stage guide for guiding the mounting table so as to be accommodated in the vacuum chamber through the opening in a direction orthogonal to the opening and the rail is installed, the mounting table, has a flange for sealing the opening is attached to the opening, and the sample stage, and the sample table drive mechanism, and a structure for supporting the flange vacuum sample stage unit is mounted, the mounting flange, the reference pin has a structure in which the reference pins implanted is positioned fitted into a reference hole provided in the outer wall of the vacuum chamber, before The mounting table includes a mounting table base guided by the guide rail, a flange supporting unit provided on the flange side of the mounting table base and supporting the flange, and the guide rail from the flange supporting unit of the mounting table base. A structure support portion provided on the side spaced apart in the guide direction, and supporting the structure, wherein the vertical direction is the first direction, the direction in which the mounting table is guided by the guide rail is the second direction, When the direction perpendicular to the first direction and the second direction is the third direction, the flange is positioned in the first direction and the third direction by the flange support portion, and the structure By positioning the structure in the first direction and the second direction by a body support portion, and fitting one end of the structure to the mounting base, the third direction There is provided a vacuum chamber and wherein the <br/> to the Me-decided.

In any of the above configurations of the first aspect of the present invention, the bottom surface of the flange and the bottom surface of the structure are the same height in the first direction,
It is preferable that the attitude of the vacuum sample stage unit in the state mounted on the mounting table is substantially the same as the attitude of the vacuum sample stage unit removed from the mounting table and installed on a horizontal plane, and the flange support unit Is preferably supported so as to sandwich both ends of the flange in the third direction, and the structure support portion includes an inclined portion having an inclination with respect to the first direction. preferably, also, preferably has a member for restricting the movement of the mounting table along the leading SL guide rail, and a lock member connected and fixed to the mounting table and said vacuum sample stage unit.

  In order to achieve the above object, the present invention provides, as a third aspect, an electrostatic latent image measuring apparatus using the vacuum chamber device according to any one of the first aspect of the present invention, A means for outputting and scanning a valence electron beam, and detecting an electrostatic latent image on a sample surface based on a detection signal obtained by scanning the valence electron beam; An electrostatic latent image measuring device is provided, which is formed by exposing a light to an exposure optical system to generate a charge distribution on a sample.

ADVANTAGE OF THE INVENTION According to this invention, the electrostatic latent image measuring apparatus which can measure an electrostatic latent image within the short time after latent image formation can be provided. In addition, the vacuum sample stage unit can be easily attached to and detached from the vacuum chamber, and workability outside the chamber can be improved for setting the installation conditions of the photoconductor as the test object and setting the exposure optical system.

A preferred embodiment of the present invention will be described.
FIG. 6 shows an example of an electrostatic latent image measurement method. In this electrostatic latent image measurement method, a measurement apparatus including a charged particle irradiation unit 10 that irradiates a charged particle beam, an exposure unit 20, a sample setting unit 16, and a secondary electron detection unit 18 is used. These are all arranged in the same chamber, and the inside of the chamber is in a vacuum.

  The charged particles herein refer to particles that are affected by an electric field or magnetic field, such as electrons and ions. In the following description, the charged particle irradiation unit 10 irradiates an electron beam and is also referred to as an electron beam irradiation unit 10.

  The electron beam irradiation unit 10 includes an electron gun 11, a condenser lens 12, a beam blanker 13, a scanning lens 14, and an objective lens 15. The electron gun 11 generates an electron beam. The condenser lens 12 converges the electron beam emitted from the electron gun 11. The beam blanker 13 turns on / off the electron beam. The scanning lens 14 scans the electron beam that has passed through the beam blanker 13. The objective lens 15 condenses the electron beam that has passed through the scanning lens 14 again. The scanning lens 14 is a so-called deflection coil. A driving power supply (not shown) is connected to each of the other lenses.

  When an ion beam is used instead of the electron beam, a liquid metal ion gun or the like is used instead of the electron gun 11.

  A scintillator, a photomultiplier tube, or the like is used for the secondary electron detector 18.

  The exposure unit 20 includes a light source 21 having a wavelength having sensitivity with respect to the photosensitive member (configuration will be described later), a collimating lens 22, an aperture 23, and an imaging lens 25. A desired beam diameter and beam profile are formed. As the light source 21, an LD (laser diode) or the like is used. Further, the light source 21 is controlled by LD control means or the like so that an appropriate exposure time and exposure energy can be irradiated. In order to form a line-shaped pattern composed of an electrostatic latent image on the sample 30, a scanning mechanism using a galvano mirror or a polygon mirror may be provided in the optical system of the exposure unit 20.

FIG. 9 shows the configuration of the photoconductor constituting the sample 30.
The photoreceptor has a structure in which a charge generation layer (CGL) and a charge transport layer (CTL) are formed on a conductive support. When the surface is exposed in a charged state, light is absorbed by the charge generation material (CGM) of the charge generation layer, and positive and negative charge carriers are generated. One of these carriers is injected into the charge transport layer by the electric field, and the other is injected into the conductive support. The carriers injected into the charge transport layer move to the surface of the charge transport layer by an electric field, and are combined with the charge on the surface of the photoreceptor to disappear. Thereby, a charge distribution, that is, an electrostatic latent image is formed on the surface of the photoreceptor.

FIG. 11 shows the configuration of the electrostatic latent image measuring apparatus. A procedure for measuring an electrostatic latent image using this apparatus will be described.
First, the electron beam irradiation unit 10 irradiates the photoreceptor sample 30 with an electron beam. The relationship between the acceleration voltage and the secondary electron emission ratio δ at this time is shown in FIG. By setting the accelerating voltage E1 higher than the accelerating voltage E0 at which the secondary electron emission ratio δ is 1, the amount of incident electrons exceeds the amount of emitted electrons, so that electrons are accumulated in the photoreceptor sample 30 and charge up occurs. . As a result, the sample 30 is uniformly charged with a negative charge. The photoconductor sample 30 can be charged to a desired charging potential by changing the acceleration voltage and the irradiation time.

  When a charged potential is formed on the photoconductor sample 30, the electron beam is once turned off.

  Next, the photoreceptor sample 30 is exposed using the optical system of the exposure unit 20. The optical system is adjusted to form a desired beam diameter and beam profile. An electrostatic latent image is formed on the photoreceptor sample 30 by exposure.

  After the electrostatic latent image is formed on the photoconductor sample 30, the measurement apparatus is switched to the observation mode. In the observation mode, the photoconductor sample 30 is scanned with an electron beam, and the emitted secondary electrons are detected by a secondary electron detector 18 made of a scintillator, a photomultiplier tube, etc., and converted into an electric signal to be subjected to potential contrast. Observe the image.

  In order to convert a potential contrast image into a potential, a conversion table representing the correlation between the potential and the signal intensity may be prepared in advance, and the potential distribution may be calculated from the signal intensity based on the conversion table.

Alternatively, a known reference potential may be arranged in the electron beam scan region, and a method of calculating the potential distribution by comparing the secondary electron signal intensity with the reference potential may be used.
As a method of arranging the reference potential, as shown in FIG. 10, there is a method of arranging a plurality of conductive substrates 34 on an insulator 33 and setting a reference potential to each of the conductive substrates 34. Specifically, the voltage of the reference voltage source is divided by a resistor, and a reference potential is applied to each conductive substrate 34.

In general, a portion having a lower potential than a portion having a high potential becomes brighter because the amount of secondary electrons emitted is larger. In FIG. 10, a portion having a relatively low potential is displayed in white and a portion having a high potential is displayed in black. In FIG. 10, reference numeral 30 denotes a photoconductor sample, 31 denotes an electrostatic latent image, and 32 denotes an electron beam scan area. Secondary electrons are detected by the secondary electron detector 18 while scanning the surface of the photoreceptor sample 30 with an electron beam. FIG. 10 also shows how the detection signal changes at that time.
The signal intensity on the secondary electron detector 18 may be corrected when it changes depending on the setting conditions. Further, calibration may be performed in advance.

  After the measurement is completed, the residual charge on the photoconductor sample 30 is removed by irradiating the entire surface of the photoconductor sample 30 with the light source 17 (LED or the like) shown in FIG.

FIG. 11 also shows a control system of the measuring apparatus.
The control system of the measuring apparatus includes an LD control unit 36, a charged particle control unit 37, an LED control unit 38, and a sample stage control unit 39. The LD control unit 36 controls the light source 21. The charged particle control unit 37 controls the scanning lens 14. The LED control unit 38 controls the light source 17 for removing residual charges. The sample stage control unit 39 controls the movement of the sample stage 16.
The LD control unit 36, charged particle control unit 37, LED control unit 38, and sample stage control unit 39 are controlled by the host computer 35. The output of the secondary electron detector 18 is detected by the secondary electron detector 41, and the detection signal is processed by the signal processor 42 and output from the measurement result output unit 43 as a secondary electron measurement result.

The secondary electron emission ratio δ is
δ = emitted electrons / incident electrons, but more strictly speaking, it is necessary to consider transmitted electrons and reflected electrons,
It is preferable to calculate δ as emission electrons = transmission electrons + reflection electrons + secondary electrons.

  When it is desired to charge with positive charge, the photosensitive member sample 30 may be irradiated with an electron beam at an acceleration voltage at which the secondary electron emission ratio is 1 or more as shown in FIG. In general sample observation by SEM, it is known that observation is performed under the condition of δ = 1 in order to avoid the influence of charge-up, and other acceleration voltages are not used. In this embodiment, the charged potential is formed by intentionally charging up.

In the above method, the electron beam is once turned off after the charged potential is formed. However, without changing it to the off state, the acceleration voltage is changed to δ = 1 so that the observation condition does not cause charge-up and exposure is performed in that state. You may make it make it.
As the charging method, another method such as contact charging may be used.

1 to 5 show the configuration of the vacuum chamber apparatus.
FIG. 1 shows a state in which the vacuum sample stage unit 60 is mounted in the vacuum chamber 50. FIG. 4 shows a state in which the vacuum sample stage unit 60 is pulled out from the vacuum chamber 50.
The vacuum chamber performs inner diameter processing on a cylindrical material and D-cuts (cut into a D-shape when viewed from above) from above to form an opening and a flange mounting portion. A guide rail attachment portion is provided on a surface parallel to the bottom surface of the vacuum chamber 50, and a guide rail 52 is attached in a direction orthogonal to the opening. In this embodiment, two guide rails 52 and a reinforcing plate 53 are used to improve the positioning accuracy and load resistance of the vacuum sample stage unit. Each of the guide rails 52 is provided with one moving table 54, and a mounting table 55 that bridges the two moving tables 54 is fastened to the guide rail 52 with screws.

FIG. 2 shows the configuration of the vacuum chamber 50. FIG. 3 shows the configuration of the vacuum sample stage unit 60.
A stage unit 62 for moving the sample in three directions in the vacuum chamber 50 is attached to the flange 61 (flange for connecting to the vacuum chamber) of the vacuum sample stage unit. A box-shaped structure is formed on the opposite side of the flange 61 from the stage, and a stage driving unit 63 (stepping motor, microhead, etc.) is attached after leakage is prevented by an O-ring. A harness for taking out electric power and signals into the vacuum chamber 50 is relayed by the field through 64 while maintaining a vacuum.

  As shown in FIG. 5, a positioning member 65 having an L-shaped cross section is fastened to the bottom of the box-shaped structure 69, the corners on both sides on the short side are chamfered, and the height of the bottom of the end surface and the bottom of the bottom of the flange Are substantially the same. Furthermore, the center of gravity of the entire vacuum sample stage unit 60 is located in a trapezoidal surface formed by connecting the end bottom surface of the positioning member 64 and the bottom surface of the lower end of the flange 61. Since it can be installed on a desk or the like while being kept almost horizontal, assembly adjustment and other operations can be easily performed.

Next, positioning of the mounting table 55 and the vacuum sample table unit 60 will be described.
The mounting table 55 includes a guide part for easily setting the vacuum sample stage unit 60, a receiving part for holding the vacuum sample stage unit 60 horizontally, and a part for ensuring stability and safety during mounting. ing.
Two guide portions are provided before and after the sliding direction. On the vacuum chamber 50 side, a U-shaped guide portion 56 having a U-shaped protrusion is provided, and abuts against the protrusion on the surface opposite to the stage of the flange 61 of the vacuum sample stage unit 60 while guiding from the outside. Since the corners of each other are R-shaped, they are guided even if there is a deviation in the direction perpendicular to the sliding direction. The other guide is provided with notches at the end of the U-shaped guide portion 56 on the side of the vacuum chamber 50 and the end of the mounting table 55 opposite to the vacuum chamber 50 to form inclined surfaces 56a and 55a, respectively. The mounting table 55 and the U-shaped guide portion 56 are guided by being fitted between the positioning member 65 and the flange 61 of the vacuum sample table unit 60 along the notch.
Positioning in the direction along the guide rail 52 is performed by holding the mounting table 55 between the opposite surface of the stage of the flange 61 and the positioning member 65.
The positioning of the vacuum sample stage unit 60 in the vertical direction is held horizontally by its own weight by appropriately setting the height of the receiving surface of the mounting table 55.

Since the positioning unit 65 of the mounting table 55 and the vacuum sample table unit 60 is sandwiched and fitted in the direction along the guide rail 52 and the direction orthogonal thereto, the mounting table 55 and the vacuum sample table unit 60 are vacuumed from the mounting table by a load at the time of attachment and detachment and normal impact. The sample stage unit 60 does not fall.
Further, by providing a tap at the rear end portion of the mounting table 55, providing a hole in the positioning member 65 of the vacuum sample table unit 60, and fastening them with the knob screws 66, further safety can be ensured.

  A tap is provided at the center of the mounting table 55, and a screw is inserted into the hole of the reinforcing plate 53 with a knob screw 66 or is abutted against the surface of the reinforcing plate 53, thereby locking the mounting table 55 or applying a brake at an arbitrary position. Can do. Since such a safety device is provided, various operations can be performed in a state where the vacuum sample stage unit 60, which is a heavy object, is removed from the vacuum chamber 50 without being removed from the mounting table 55, and safety and work can be performed. Efficiency and increase.

  The vacuum sample stage unit 60 is attached to the vacuum chamber 50 by pushing the vacuum sample stage unit 60 toward the vacuum chamber 50 using the handles 67 attached to the left and right sides of the box-shaped structure in the state of being mounted on the mounting table 55. The reference surface (butting surface) of the flange 61 is formed by compressing a predetermined amount of the O-ring to the flange mounting surface (contact surface) of the vacuum chamber 50 and screwing it. At this time, holes serving as the main reference and oblong holes serving as the reference are formed at a predetermined pitch on the flange mounting surface of the vacuum chamber 50 (these are referred to as reference holes 57), and the tip implanted in the flange 61 is tapered. By fitting with the reference pin 68 in the shape, positioning is performed with high accuracy, and the positional relationship with an electron gun (not shown) provided in the vacuum chamber 50 is maintained with high accuracy by suppressing variation due to attachment and detachment.

As described above, according to the electrostatic latent image measuring apparatus according to the present embodiment, the vacuum sample table unit 60 and the mounting table 55, which are heavy objects, are positioned with high accuracy, and further easily along the guide rail 52. Can be moved. By fitting the reference pin 68 implanted in the flange 61 into the reference hole 57 provided in the vacuum chamber 50, the positional relationship between the electron gun and the vacuum sample table is maintained with high accuracy.
In addition, operability is greatly improved.

In addition, said description is an example of suitable implementation of this invention, and this invention is not limited to this.
For example, in the above embodiment, the mounting table and the U-shaped guide portion are cut out to form the inclined surface, but rounding (R processing) may be performed instead of chamfering.
As described above, the present invention can be variously modified.

It is a figure which shows the structure of the vacuum chamber apparatus concerning suitable embodiment of this invention. It is a figure which shows the structure of a vacuum chamber. It is a figure which shows the structure of a vacuum sample stand unit. It is a figure which shows the state which pulled out the vacuum sample stand unit from the vacuum chamber. It is a figure which shows the positioning state of a guide rail direction. It is a figure which shows an example of the electrostatic latent image measuring method. It is a figure which shows the relationship between acceleration voltage and secondary electron emission ratio (delta). It is a figure which shows the structure of an electrophotographic apparatus. It is a figure which shows the structure of a photoreceptor. It is a figure which shows an example of the method of arrange | positioning a reference electric potential. It is a figure which shows the structure of an electrostatic latent image measuring device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Electron gun 12 Condenser lens 13 Beam blanker 14 Scan lens 15 Objective lens 16 Sample stand 17 Light source 18 Secondary electron detection part 20 Exposure part 21 Light source 22 Collimating lens 23 Aperture 25 Imaging lens 30 Sample 31 Electrostatic latent image 32 Beam scan Region 33 Insulator 34 Conductive substrate 35 Computer 36 LD control unit 37 Charged particle control unit 38 LED control unit 39 Sample stage control unit 41 Secondary electron detector 42 Signal processing unit 43 Measurement result output unit 50 Vacuum chamber 52 Guide rail 53 Reinforcement plate 54 Moving table 55 Mounting table 56 U-shaped guide unit 57 Reference hole 60 Vacuum sample table unit 61 Flange 62 Stage unit 63 Stage drive unit 64 Field through 65 Positioning member 66 Knob screw 67 Handle 68 Reference pin 69 Box type Structure

Claims (6)

A vacuum chamber device comprising a sample stage that holds a sample and is accommodated in a vacuum chamber through an opening on one side and is movable in any direction,
A mounting table and a guide rail for guiding the mounting table in a direction perpendicular to the opening so that the sample table is accommodated in the vacuum chamber through the opening on the outer wall of the vacuum chamber. Installed,
The mounting table is mounted with a vacuum sample table unit having a flange attached to the opening and sealing the opening, the sample table, a driving mechanism for the sample table, and a structure that supports the flange. And
The mounting flange has a structure in which a reference pin is implanted and the reference pin is fitted and positioned in a reference hole provided in an outer wall portion of the vacuum chamber.
The mounting table includes a mounting base that is guided by the guide rail, a flange support that is provided on the flange side of the mounting base, and supports the flange, and the guide from the flange support of the mounting base. A structure support part that is provided on the side of the rail that is spaced apart in the guide direction and supports the structure,
When the vertical direction is the first direction, the direction in which the mounting table is guided by the guide rail is the second direction, and the first direction and the direction perpendicular to the second direction are the third direction,
Positioning the flange in the first direction and the third direction by the flange support part, and positioning the structure in the first direction and the second direction by the structure support part; And the vacuum chamber apparatus characterized by positioning in a 3rd direction by fitting the one end part of the said structure to the mounting base mentioned above.   In the first direction, the bottom surface of the flange and the bottom surface of the structure are the same height, and the posture of the vacuum sample stage unit in a state of being mounted on the mounting table and the state of being removed from the mounting table and installed on a horizontal plane The vacuum chamber apparatus according to claim 1, wherein the posture of the vacuum sample stage unit is substantially the same.   The vacuum chamber apparatus according to claim 1, wherein the flange support portion supports the flange so as to sandwich both ends of the flange in the third direction.   The vacuum chamber apparatus according to claim 1, wherein the structure support portion includes an inclined portion having an inclination with respect to the first direction. A member for restricting the movement of the mounting table along said guide rail, claim 1, wherein 4 to have a locking member connected and fixed to the mounting table and said vacuum sample stage unit 1 The vacuum chamber device according to item. An electrostatic latent image measuring device using the vacuum chamber device according to any one of claims 1 to 5 ,
A means for outputting and scanning the valence electron beam, and detecting an electrostatic latent image on the sample surface based on a detection signal obtained by scanning the valence electron beam;
The electrostatic latent image is formed by exposing a charged sample with an exposure optical system to generate a charge distribution on the sample.

Images