JP6118870B2 - Sample observation method - Google Patents

Description

  The present invention relates to a technique that can be inspected or observed by charged particle technology and optical technology. For example, the present invention relates to an observation technique capable of observing a sample to be observed with a charged particle microscope and an optical microscope that are observable at atmospheric pressure or a predetermined gas atmosphere.

  In order to observe a minute region of an object, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like is used. In general, in these apparatuses, the second casing for placing the sample is evacuated and the sample atmosphere is evacuated to perform imaging. On the other hand, there is a great need for observing samples that are damaged or change their state, such as biochemical samples and liquid samples, under atmospheric pressure using both an optical microscope and an electron microscope. SEM devices that can be observed below have been developed.

  These devices, in principle, provide a diaphragm capable of transmitting an electron beam between an electron optical system and a sample to partition a vacuum state and an atmospheric state. In either case, a thin film is provided between the sample and the electron optical system. Common in terms of provision.

  In Patent Document 1, the electron source side of the electron optical column is disposed downward, the objective lens side is disposed upward, and a thin film capable of transmitting an electron beam is provided on the electron beam exit hole side at the end of the electron optical column. Atmospheric pressure SEM is described. In the invention described in Patent Document 1, a sample to be observed is placed directly on a thin film, a primary electron beam is irradiated from the lower surface of the sample, reflected electrons or secondary electrons are detected, and SEM observation is performed. The sample is arranged in an annular member installed around the thin film and the thin film liquid, and an atmospheric pressure SEM suitable for observing the sample in the liquid is described. Further, it is described that the optical microscope observation and the electron microscope observation can be performed by arranging the optical axis of the optical microscope and the optical axis of the electron microscope so as to be coaxial.

  Patent Document 2 describes an apparatus configuration in which an optical microscope and an electron microscope on which a diaphragm is arranged are arranged side by side to alternately observe a sample arranged at atmospheric pressure with an optical microscope and an electron microscope. .

JP 2008-153086 A (US Patent Publication No. 2010/0096549) JP 2001-241940 A (US Patent Publication 2001/0008272)

  Both conventional charged particle microscopes and charged particle beam devices equipped with an observation function under atmospheric pressure are specially manufactured for observation under atmospheric pressure. There was no device that could easily perform observation under atmospheric pressure / gas atmosphere.

  For example, the atmospheric pressure SEM described in Patent Document 1 is a structurally very special device, and SEM observation in a normal high vacuum atmosphere cannot be performed. In addition, since the optical microscope and the electron microscope are opposed to each other, the sample that can be observed from both sides of the sample by the optical microscope and the electron microscope is limited to only a transparent sample such as a liquid, and there is a problem in usability.

  For example, in this apparatus, the same part such as a semiconductor fine pattern formed on a silicon substrate cannot be observed with an optical microscope and an electron microscope. In addition, even in the same sample, the observation directions of the optical microscope and the electron microscope are opposite to each other, so that complicated processing is required to collate the observation results.

  Patent Document 2 is also a structurally very special device and cannot be observed with an electron microscope in which a normal sample is placed under vacuum. In particular, since the electron beam lens is exposed to the atmosphere, it is difficult to accurately observe the sample with the electron beam, and it can be used only limitedly.

  The present invention has been made in view of such problems, and provides an inspection apparatus, an observation apparatus, an inspection method, or an observation method capable of accurately inspecting or observing a sample with a charged particle technique and an optical technique with ease of use. For the purpose.

According to one aspect of the present invention, there is provided a sample observation method using a charged particle beam apparatus having a charged particle optical column that irradiates a charged particle beam, a vacuum chamber, and a sample chamber in which a sample is stored, The sample chamber is maintained at a higher pressure than the vacuum chamber by a thin film that transmits the charged particle beam, and the distance between the height of the lower surface of the thin film and the height of the lower end of the barrel of the optical microscope is determined, A sample observation method is provided in which a distance from the lens barrel is measured, and a distance between the sample and the thin film is set based on the distance and the relationship .

  According to the present invention, it is possible to provide an inspection apparatus, an observation apparatus, an inspection method, or an observation method that is easy to use and can accurately inspect or observe a sample by a charged particle technique and an optical technique.

The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 1st embodiment. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 2nd embodiment. The whole block diagram of the observation apparatus as a charged particle microscope provided with the optical microscope in 3rd embodiment. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 4th embodiment. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 5th embodiment. The whole block diagram of the observation apparatus as a charged particle microscope provided with the optical microscope in 6th embodiment. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 7th embodiment. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 8th embodiment. The block diagram which pulled out the sample stage of the observation apparatus as a charged particle microscope provided with the optical microscope in 8th Embodiment with the cover member. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 9th embodiment. The whole block diagram of the observation apparatus as a charged particle microscope which comprised the optical microscope in 9th embodiment.

  Each embodiment will be described below with reference to the drawings.

Note that as an aspect of the present invention, an attachment that can store the sample while maintaining an internal pressure higher than the pressure in the vacuum chamber with respect to the vacuum chamber provided in the charged particle microscope is the vacuum. Usability is improved by inserting and installing from the opening of the chamber. The opening part of a vacuum chamber is provided in the side surface of a vacuum chamber, for example. In addition, the attachment has a function of holding a thin film that allows the primary charged particle beam to pass through or pass through the inside of the attachment, and is configured to ensure a pressure difference between the vacuum chamber and the inside of the attachment. Further, by attaching an optical microscope that detects light using light as a light source to the vacuum chamber or the attachment, observation with a charged particle microscope and an optical microscope can be performed.

  Here, the attachment is used by being inserted into the housing from the opening of the vacuum chamber. In the following description, the vacuum chamber may be referred to as a first housing, and the attachment may be referred to as a second housing for the vacuum chamber.

<First embodiment>
In the first embodiment, the most basic embodiment will be described. In FIG. 1, the whole block diagram of the observation apparatus (inspection apparatus) as a charged particle microscope provided with the optical microscope in this embodiment is shown. The charged particle microscope shown in FIG. 1 mainly includes a charged particle optical column 2 as a charged particle irradiation unit that irradiates a primary charged particle beam, and a first housing that supports the charged particle optical column 2 with respect to the apparatus installation surface. The body (vacuum chamber) 7, the second housing (attachment) 121 used by being inserted into the first housing 7, an optical microscope, and a control system for controlling them. The first housing 7 forms at least a part of the first space that can be maintained in a vacuum state, which is at least a part of the region while the primary charged particle beam emitted from the charged particle optical column 2 reaches the sample. To do. The second casing 121 is provided in the first casing 7 and forms at least a part of a second space in which a sample can be stored.

  When the charged particle microscope is used, the charged particle optical column 2 and the inside of the first housing are evacuated by the vacuum pump 4. The start / stop operation of the vacuum pump 4 is also controlled by the control system. Although only one vacuum pump 4 is shown in the figure, two or more vacuum pumps may be provided.

  The charged particle optical column 2 is an element such as a charged particle source 0 that generates a charged particle beam, an optical lens 1 that focuses the generated charged particle beam and guides it to the lower part of the column and scans the sample 6 as a primary charged particle beam. Consists of. The charged particle optical column 2 is installed so as to protrude into the first housing 7, and is fixed to the first housing 7 through a vacuum sealing member 123. A detector 3 for detecting secondary charged particles (secondary electrons or reflected electrons) obtained by irradiation with the primary charged particle beam is disposed at the end of the charged particle optical column 2. The detector 3 as the detection unit is preferably provided inside the first housing 7 as shown in FIG. Thereby, secondary charged particles (secondary electrons or reflected electrons) obtained by irradiation with the primary charged particle beam can be detected in a vacuum, and can be detected more accurately. Preferably, the detector 3 may be provided in the charged particle optical column 2. Further, the detector 3 may be disposed inside the second housing 121 depending on circumstances.

The charged particle microscope of the present embodiment has a control system such as a personal computer 35 used by the user of the apparatus, an upper control unit 36 connected to the personal computer 35 for communication, and a command sent from the upper control unit 36 in accordance with an evacuation system and a charge. A lower control unit 37 that controls the particle optical system and the like is provided. The personal computer 35 includes a monitor on which an operation screen (GUI) of the apparatus is displayed, and input means for an operation screen such as a keyboard and a mouse. The upper control unit 36, the lower control unit 37, and the personal computer 35 are connected by communication lines 43 and 44, respectively.

  The lower control unit 37 is a part that transmits and receives control signals for controlling the vacuum pump 4, the charged particle source 0, the optical lens 1, the light source 201, the lens barrel 200, and the like. It converts into a signal and transmits to the high-order control part 36. Although the output signal from the detector 3 is connected to the lower control unit 37 in the figure, an amplifier such as a preamplifier may be interposed.

  The upper control unit 36 and the lower control unit 37 may include a mixture of analog circuits, digital circuits, etc., and the upper control unit 36 and the lower control unit 37 may be unified. The configuration of the control system shown in FIG. 1 is merely an example, and modifications of the control unit, the valve, the vacuum pump, the communication wiring, and the like can be applied to the SEM of this embodiment as long as the functions intended by this embodiment are satisfied. It belongs to the category of charged particle beam equipment.

  A vacuum pipe 16 having one end connected to the vacuum pump 4 is connected to the first housing 7 so that the inside can be maintained in a vacuum state. At the same time, a leak valve 14 for releasing the inside of the housing to the atmosphere is provided, and the inside of the first housing 7 can be opened to the atmosphere during maintenance. The leak valve 14 may not be provided, and may be two or more. Moreover, the arrangement location in the 1st housing | casing 7 is not restricted to the location shown by FIG. 1, You may arrange | position in the other position on the 1st housing | casing 7. FIG. Furthermore, the first housing 7 has an opening on the side surface, and the second housing 121 is inserted through the opening.

  The second housing 121 includes a rectangular parallelepiped main body 131, a mating portion 132, and a holding portion 132A. The main body 131 has a function of storing the sample 6 to be observed, and is inserted into the first housing 7 through the opening. The mating portion 132 forms a mating surface with the outer wall surface on the side surface side where the opening of the first housing 7 is provided, and is fixed to the outer wall surface on the side surface side via the vacuum sealing member 126. The holding unit 132A is configured to hold an optical microscope (such as the lens barrel 200).

  As a result, the entire second housing 121 is fitted into the first housing 7. The opening is most easily manufactured using the opening for loading and unloading the sample originally provided in the vacuum sample chamber of the charged particle microscope. That is, if the second casing 121 is manufactured according to the size of the hole that is originally open and the vacuum sealing member 126 is attached around the hole, the modification of the apparatus is minimized. That is, the apparatus can be modified without greatly changing the configuration of the conventional high vacuum type charged particle microscope.

On the upper surface side of the main body 131, the thin film 10 is provided at a position immediately below the charged particle optical column 2 when the entire second housing 121 is fitted into the first housing 7. The thin film 10 can transmit or pass the primary charged particle beam emitted from the lower end of the charged particle optical column 2, and the primary charged particle beam finally reaches the sample 6 through the thin film 10. It is configured to
When the charged particle beam is an electron beam, the thickness of the thin film 10 is preferably set to a thickness that can transmit the electron beam, typically about 20 μm or less. In place of the thin film, an aperture member having a primary charged particle beam passage hole may be used. In this case, the hole diameter should be about 1 mm ² or less because of the requirement that a differential vacuum pumping is possible with a realistic vacuum pump. Is desirable. When the charged particle beam is an ion, it is difficult to penetrate without damaging the thin film, so an aperture having an area of about 1 mm ² or less is used.

  The one-dot chain line in the figure indicates the optical axis 203 of the primary charged particle beam, and the charged particle optical column 2, the first housing 7, and the thin film 10 are arranged coaxially with the primary charged particle beam optical axis. It is configured. The distance between the sample 6 and the thin film 10 is adjusted by a sample stage 17 having an appropriate height. The sample stage 17 is configured as a sample placement unit on which a sample is placed.

  The optical microscope is held by the holding portion 132 </ b> A of the second housing 121. The optical microscope includes at least a light source 201 for irradiating light and a lens barrel 200 of the optical microscope. The lens barrel 200 includes at least an optical lens and an image detection unit for detecting an image. The optical microscope is configured to use an image as a signal such as a digital signal and transfer data through the communication line 43. The lens barrel 200 as an optical observation unit is configured to detect light from the sample 6 from the same direction as the charged particle optical lens barrel 2.

  The light detection unit such as an optical microscope may be configured with a detection element such as a CCD element that directly converts light into a digital signal, or may be configured with an eyepiece that can be directly observed visually.

  The distance between the optical axis 204 of the lens barrel 200 and the optical axis 203 of the electron microscope is set to a predetermined distance as a known distance.

  After observing the sample with the optical microscope, the same part can be observed with the optical microscope and the electron microscope by moving the sample stage 17 by the predetermined distance. In addition, unlike the configuration in which the optical microscope and the electron microscope face each other as described in the cited document 1, it is possible to observe the same part from the same direction, and the usability can be improved.

  As shown in FIG. 1, the side surface of the second housing 121 is an open surface, and the sample 6 stored inside the second housing 121 (right side of the dotted line in the figure; hereinafter referred to as the second space 12) is During observation, it is placed at atmospheric pressure. On the other hand, a vacuum pump 4 is connected to the first housing 7, and a closed space (hereinafter referred to as a first space) constituted by the inner wall surface of the first housing 7, the outer wall surface of the second housing 121, and the thin film 10. 11) can be evacuated. Therefore, it is not an apparatus in which the electron beam lens is exposed to the atmosphere as described in Patent Document 2, but the charged particle optical column 2 and the detector 3 can be maintained in a vacuum state during the operation of the apparatus, and the sample 6 can be maintained at atmospheric pressure, and the sample 6 can be accurately observed. In addition, the sample 6 placed on the sample stage 17 is irradiated with light, the light from the sample 6 is detected by the lens barrel 200, and the sample 6 placed on the sample stage 17 is charged with the charged particle optical mirror. The primary charged particle beam emitted from the tube 2 can be moved to a position where it can be irradiated, and the primary charged particle beam emitted from the charged particle optical column 2 from the same direction as the column 200 with respect to the sample 6 can be maintained in a vacuum state. The sample 6 placed on the sample stage 17 passes through the thin film 10 that passes through the first space 11, is disposed on the same axis of the charged particle optical column 2, and separates the first space 11 and the second space 12. Irradiation can be performed, and the charged particle beam can be detected by the detector 3, and a sample inspection or sample observation method is realized.

  Furthermore, since the second casing 121 has an open surface, the sample 6 can be freely exchanged during observation with an optical microscope or an electron microscope.

  Further, an inspection apparatus or an observation apparatus that can inspect or observe even a relatively large sample at atmospheric pressure is realized.

  Preferably, the optical axis 204 of the optical microscope barrel 200 and the optical axis 203 of the charged particle optical barrel 2 are preferably provided in parallel. This makes it possible to further observe the same part from the same direction. If the same part can be observed from substantially the same direction, the optical axis 204 of the lens barrel 200 and the optical axis 203 of the electron microscope may be arranged obliquely. The optical microscope barrel 200 of the optical microscope that detects light from the sample 6 from the same direction as the charged particle optical barrel 2 in this specification is opposite to the optical microscope and the electron microscope described in the cited document 1. Unlike the configuration, the charged particle optical lens barrel 2 and the lens barrel 200 are included if they are arranged above the sample 6.

  The thin film 10 is disposed on the same axis of the charged particle optical column 2 when the primary charged particle beam irradiated from the charged particle optical column 2 irradiates the sample 6, and the first space 11 and the second space are arranged. 12 functions as a partition wall separating 12.

<Second Embodiment>
A second embodiment will be described. FIG. 2 shows an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the second embodiment. The second embodiment differs from the first embodiment in that it generally includes a thin film holding member 47 and the inside of the second housing 121 is in an atmospheric atmosphere, gas atmosphere, or vacuum atmosphere of 1 atm. The configuration is such that the sample stage 5 as the sample mounting portion is provided with a drive system. In the following description, the description overlapping with the first embodiment is omitted as much as possible.

  In the present embodiment, unlike the first embodiment, the thin film 10 is detachably fixed to the upper surface of the main body 131 of the second housing 121 via the thin film holding member 47. The thin film 10 is fixed to the thin film holding member 47 so as to be vacuum-sealed. However, a vacuum sealing member 124 such as an O-ring may be used, or may be fixed with an organic material such as an adhesive or a tape. May be.

The thin film holding member 47 is detachably fixed to the lower surface side of the ceiling plate of the second housing 121 via a vacuum sealing member. The thin film 10 is very thin with a thickness of about 20 μm or less because of the requirement for transmission of the electron beam, and therefore there is a possibility that it deteriorates with time or breaks during observation preparation. On the other hand, since the thin film 10 is thin, it is very difficult to handle it directly. As in this embodiment, the thin film 10 can be handled through the thin film holding member 47 instead of directly.
In particular, replacement is very easy. That is, when the thin film 10 is damaged, the thin film holding member 47 may be replaced. Even if the thin film 10 must be replaced directly, the thin film holding member 47 is taken out of the apparatus and the thin film 10 is replaced. Can be done externally. In addition, it is the same as that of 1st embodiment that the aperture member which has a hole of about 1 mm < ² > or less can be used instead of a thin film.

  The open surface of the second housing 121 can be covered with the lid member 122, and various functions can be realized. This will be described below.

  The observation apparatus according to the present embodiment has a function of supplying a replacement gas into the second housing 121. The electron beam emitted from the lower end of the charged particle optical column 2 passes through the first space 11 maintained at a high vacuum, passes through the thin film 10 (or aperture member) shown in FIG. Or it penetrate | invades into the 2nd space 12 maintained by the low vacuum degree (than 1st space). However, since the electron beam is scattered by gas molecules in a low vacuum space, the mean free path is shortened. That is, when the distance between the thin film 10 and the sample 6 is large, secondary electrons or reflected electrons generated by electron beam or electron beam irradiation do not reach the sample. On the other hand, the scattering probability of electron beams is proportional to the mass number of gas molecules. Therefore, if the second space 12 is replaced with gas molecules having a lighter mass number than the atmosphere, the scattering probability of the electron beam decreases and the electron beam can reach the sample. As the type of the replacement gas, if the gas is lighter than the atmosphere, such as nitrogen or water vapor, the effect of improving the image S / N can be seen, but helium gas or hydrogen gas having a lighter mass has a better image S / N. Great improvement effect.

  The lens barrel 200 of the optical microscope is configured such that the upper part is in the outside air space outside the apparatus, and the lower part, that is, at least the objective lens is arranged in the second space 12. The lens barrel 200 is fixed to the second housing 121 so as to be vacuum-sealed. However, a vacuum sealing member 124 such as an O-ring may be used, or an organic material such as an adhesive or a tape. It may be fixed with. The light source 201 of the lens barrel 200 of the optical microscope is configured to be disposed in the second space 12.

A general optical microscope can be observed at a higher magnification when the distance between the objective lens and the sample is shorter, but in this embodiment, the light source 201 of the optical microscope and the objective lens as the detection unit of the lens barrel 200 are in the second space. The sample 6 can be observed at a closer position.

  For the above reasons, in the observation apparatus of the present embodiment, the lid member 122 is provided with an attachment portion (gas introduction portion) for the gas supply pipe 100. The gas supply pipe 100 is connected to the gas cylinder 103 by the connecting portion 102, whereby the replacement gas is introduced into the second space 12. A gas control valve 101 is arranged in the middle of the gas supply pipe 100, and the flow rate of the replacement gas flowing through the pipe can be controlled. For this reason, a signal line extends from the gas control valve 101 to the lower control unit 37, and the apparatus user can control the flow rate of the replacement gas on the operation screen displayed on the monitor of the personal computer 35.

Since the replacement gas is a light element gas, it easily accumulates in the upper part of the second space 12, and the lower side is difficult to replace. Therefore, it is preferable to provide an opening on the lower side of the attachment position of the gas supply pipe 100 with the lid member 122 (the attachment position of the pressure regulating valve 104 in FIG. 2). Thereby, since it pushes by the light element gas introduced from the gas introduction part and atmospheric gas is discharged | emitted from lower opening, the inside of the 2nd housing | casing 121 can be substituted efficiently. Note that this opening may also be used as a rough exhaust port described later.

A vacuum exhaust port may be provided in the second casing 121 or the lid member 122. By connecting a vacuum pump to the evacuation port, the second space 12 can be evacuated. This makes it possible to observe an electron microscope in an ultra-low vacuum state such as 0.1 atm, which cannot be realized by a normal SEM.

Preferably, the replacement gas may be introduced after the second casing 121 is once evacuated from the evacuation port. The vacuum evacuation in this case does not require high vacuum evacuation because the atmospheric gas component remaining in the second housing 121 may be reduced to a certain amount or less, and rough evacuation is sufficient. However, when observing a sample containing moisture such as a biological sample, the sample once placed in a vacuum state changes its state due to evaporation of moisture. Therefore, as described above, it is preferable to introduce the replacement gas directly from the air atmosphere. The opening can be closed in the second space 12 by closing the opening with a lid member after the introduction of the replacement gas.

  If a three-way valve is attached to the position of the opening, this opening can be used also as a rough exhaust port and an air leak exhaust port. That is, if one of the three-way valves is attached to the lid member 122, one is connected to the rough exhaust vacuum pump, and the leak valve is attached to the other one, the above-described dual exhaust port can be realized.

  A pressure regulating valve 104 may be provided instead of the above-described opening. The pressure regulating valve 104 has a function of automatically opening the valve when the internal pressure of the second housing 121 becomes 1 atm or more. By providing a pressure regulating valve with such a function, when light element gas is introduced, it automatically opens when the internal pressure reaches 1 atm or more and discharges atmospheric gas components such as nitrogen and oxygen to the outside of the device. The element gas can be filled in the apparatus. Note that the illustrated gas cylinder 103 may be provided in the observation apparatus or may be attached later by the apparatus user.

  Next, a method for adjusting the position of the sample 6 will be described. The observation apparatus of this embodiment includes a sample stage 5 as a position adjustment means for the observation visual field. The sample stage 5 includes an XY drive mechanism in the in-plane direction and a Z-axis drive mechanism in the height direction. A support plate 107 serving as a bottom plate for supporting the sample stage 5 is attached to the lid member 122, and the sample stage 5 is fixed to the support plate 107. The support plate 107 is attached to the surface of the lid member 122 facing the second housing 121 so as to extend toward the inside of the second housing 121. Support shafts extend from the Z-axis drive mechanism and the XY drive mechanism, respectively, and are connected to the operation knob 108 and the operation knob 109, respectively. The apparatus user adjusts the position of the sample 6 in the second housing 121 by operating these operation knobs 108 and 109.

  When adjusting the position of the sample, the position in the height direction is usually adjusted after determining the position in the in-plane direction. However, in order to prevent the thin film 10 from being damaged, the position of the sample 6 in the height direction is adjusted. It is necessary to adjust so that it does not get too close. Therefore, in the observation apparatus of this embodiment, the distance between the sample 6 and the lens barrel 200 is measured in advance by an optical microscope (the light source 201 and the lens barrel 200), and the measured value and the lower surface of the thin film 10 determined in advance are measured. The distance between the sample 6 and the thin film 10 may be set based on the relationship between the height of the lens barrel 200 and the height of the lower end of the lens barrel 200.

  Next, a moving mechanism capable of moving the sample stage 5 between a position where the sample 6 can be observed with the optical microscope and a position where the sample 6 can be observed with the charged particle microscope will be described. This moving mechanism detects the light from the sample 6 by the first position where the primary charged particle beam irradiated from the charged particle optical column 2 irradiates the sample 6 onto the sample 6 and the column 200 of the optical microscope. Configured to be movable between the second position and the second position. The moving mechanism can also serve as a replacement function for the sample 6. The observation apparatus of this embodiment includes a lid member support member 19 and a bottom plate 20 on the bottom surface of the first housing 7 and the lower end portion of the lid member 122, respectively.

The bottom plate 20 includes a column 18 that is used as a guide when the sample stage 5 is moved. In a normal state, the support column 18 is stored in a storage unit provided on the bottom plate 20, and is configured to extend in the pull-out direction of the lid member 122 when the sample stage 5 is moved. The storage portion provided in the support column 18 and the bottom plate 20 is configured to have a length that can be moved at least between the position where the sample 6 can be observed with the charged particle microscope and the position where the sample 6 can be observed with the optical microscope. Has been. By using this moving mechanism, after observing the sample 6 with an optical microscope, the sample 6 can be observed with a charged particle microscope. That is, by extending the column 18 in the pulling-out direction of the lid member 122 or in a state where the column 18 is stretched, the sample stage 5 can be observed at the position where the sample 6 can be observed with the optical microscope, that is, the lens barrel 200 of the optical microscope. It is possible to arrange the observation target portion of the sample 6 on the optical axis 204 of the sample. In addition, the column 18 can be stored in the storage portion of the bottom plate 20 in the direction opposite to the direction in which the lid member 122 is pulled out, or the sample 6 can be observed with the charged particle microscope. It is possible to place the observation target portion of the sample 6 on the position, that is, on the optical axis 203 of the charged particle optical column 2 of the charged particle microscope.

Moreover, the support | pillar 18 is provided with the function used as a guide in the case of removal. It is configured to have a function of extending in the pull-out direction of the lid member 122 at the time of removal. At the same time, the support column 18 is fixed to the lid member support member 19, and when the lid member 122 is removed from the second housing 121, the lid member 122 and the observation apparatus main body are not completely separated. Yes. Thereby, the sample stage 5 or the sample 6 can be prevented from dropping. The lid member 122 is detachably fixed to the second housing 121 via a vacuum sealing member 125. On the other hand, the cover member support member 19 is also detachably fixed to the bottom plate 20, and the cover member 122 and the cover member support member 19 can be removed from the second housing 121 in their entirety.

  In the case of observing the sample 6 with the charged particle microscope after observing the sample 6 with the optical microscope, first, the sample stage 5 is placed at a position where the sample 6 can be observed with the optical microscope, that is, the lens barrel 200 of the optical microscope. The observation target part of the sample 6 is placed on the optical axis 204 and observed. Next, the lid member 122 is pushed into the second housing 121, and the sample 6 is placed on the sample stage 5 at a position where the sample 6 can be observed with a charged particle microscope. After fixing the lid member 122 to the mating portion 132 with a fastening member (not shown), a replacement gas is introduced. Next, the Z-axis operation knob of the sample stage 5 is turned to adjust the position by the equal position adjusting means for bringing the sample 6 closer to the thin film 10, and the observation target portion of the sample 6 observed with the optical microscope is observed with the charged particle microscope. To do. The above operation can be performed while the operation of the charged particle optical column 2 is continued. Therefore, the observation apparatus of the present embodiment can start observation quickly.

When the sample is carried into the second casing 121, first, the sample 6 is moved away from the thin film 10 by turning the Z-axis operation knob of the sample stage 5. Next, the pressure regulating valve 104 is opened, and the inside of the second housing is opened to the atmosphere. Thereafter, after confirming that the inside of the second housing is not in a reduced pressure state or an extremely pressurized state, the lid member 122 is pulled out to the side opposite to the apparatus main body. As a result, the sample 6 can be exchanged. After the sample replacement, the lid member 122 is pushed into the second housing 121, and the lid member 122 is fixed to the mating portion 132 with a fastening member (not shown), and then a replacement gas is introduced. The above operation can be performed while the operation of the charged particle optical column 2 is continued. Therefore, the observation apparatus of this embodiment can start observation quickly after exchanging the sample.

  In the present embodiment, the sample stage 5 and its operation knobs 108 and 109, the gas supply pipe 100, and the pressure adjustment valve 104 are all attached to the lid member 122 in an integrated manner. Accordingly, the apparatus user performs the operation of the operation knobs 108 and 109, the operation of moving the sample stage, the operation of exchanging the sample, or the operation of detaching the gas supply pipe 100 and the pressure adjustment valve 104 on the same surface of the first housing. be able to. Therefore, operability and usability can be improved as compared with a scanning electron microscope having a configuration in which the above-described components are separately attached to other surfaces of the sample chamber.

<Third embodiment>
A third embodiment will be described. FIG. 3 is an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the third embodiment. The third embodiment is different from the second embodiment in that the entire barrel 200 of the optical microscope is generally housed in the second space 12 and the communication line 43 is drawn out of the apparatus. And a drive mechanism 205 for changing the position of the optical microscope. In the following description, the description overlapping with the second embodiment is omitted as much as possible.

In the present embodiment, the upper side of the holding portion 132A of the second housing 121 protrudes, and the height position of the upper surface of the holding portion 132A and the height position of the upper surface of the first housing 7 are substantially matched. ing. A driving mechanism 205 that moves the optical microscope in the perspective direction (vertical direction) with respect to the sample 6 is provided on the inner wall of the holding portion 132A. In a general optical microscope, an image can be focused by controlling the distance between an optical lens such as an objective lens and a sample. By moving the entire optical microscope in the perspective direction with respect to the sample 6 by the drive mechanism 205, the focus can be adjusted without changing the height position of the sample 6. In the present embodiment, it is particularly suitable when the image detection unit provided in the optical microscope for detecting an image is a CCD element.

  Note that the drive mechanism 205 may be configured to be movable between the light source 201 and the lens barrel 200 of the optical microscope, or may be configured to be able to move only the optical lens such as the objective lens of the light source 201 and the lens barrel 200. It is good that only the lens barrel 200 can be moved without moving the light source 201, or only the optical lens such as the objective lens of the lens barrel 200 can be moved without moving the light source 201. You may do it. In other words, a part or all of the optical microscope may be configured to move in the perspective direction with respect to the sample 6.

  The distance between the optical axis 204 of the lens barrel 200 and the optical axis 203 of the electron microscope is set to a predetermined distance as a known distance.

  After observing the sample with the optical microscope, the same part can be observed with the optical microscope and the electron microscope by moving the sample stage 17 by the predetermined distance. Further, unlike the configuration in which the optical microscope and the electron microscope are opposed to each other as described in the cited document 1, it is possible to observe the same part from substantially the same direction, and usability can be improved.

<Fourth embodiment>
A fourth embodiment will be described. FIG. 4 shows an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the fourth embodiment. The fourth embodiment differs from the second embodiment in that the light source 201 of the optical microscope is generally arranged below the sample 6 and the sample stage as the sample mounting portion. 5 is that a hollow portion 206 is formed as a transmissive portion through which light from the light source 201 can be transmitted. In the following description, the description overlapping with the second embodiment is omitted as much as possible.

  When the sample 6 is not transparent, the light source 201 needs to be irradiated from the upper side of the sample 6. However, when the sample 6 is transparent or transmits light, the light source 201 should be disposed below the sample 6. Thus, an optical microscope image in which light is transmitted through the sample 6 can be acquired. Preferably, the light source 201 is disposed below the sample stage 5 as shown in FIG. In this case, the cavity 206 is formed in the sample stage 5 so that light can be transmitted.

  Note that the optical microscope may be configured to be detachable. When the optical microscope is removed from the holding portion 132A, a lid or the like may be placed on the place where the optical microscope is located so that the atmosphere outside the apparatus and the inside of the second space 12 can be separated.

<Fifth embodiment>
The fifth embodiment will be described. FIG. 5 shows an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the fifth embodiment. The fifth embodiment differs from the second embodiment in that it generally shows a form used as a high vacuum SEM equipped with an optical microscope. In the following description, the description overlapping with the second embodiment is omitted as much as possible.

  As shown in this embodiment, it can also be used as a high vacuum SEM equipped with an optical microscope.

  FIG. 5 shows the attachment positions of the gas supply pipe 100 and the pressure adjustment valve 104 after the gas supply pipe 100 and the pressure adjustment valve 104 are removed from the cover member 122 with the lid member 122 fixed to the second housing 121. The charged particle microscope provided with the optical microscope of the state closed with the cover member 130 is shown. If the thin film holding member 47 is removed from the second casing 121 by the operation before and after this, the first space 11 and the second space 12 can be connected, and the inside of the second casing is evacuated by the vacuum pump 4. It becomes possible. As a result, high vacuum SEM observation is possible with the second housing 121 attached.

  As a modification of the configuration of FIG. 5, the entire second housing 121 with the thin film holding member 47 attached and the optical microscope are removed, and the lid member 122 is directly fixed to the mating surface of the first housing 7. May be.

  Also with this configuration, the first space 11 and the second space 12 can be connected, and the inside of the second housing 121 can be evacuated by the vacuum pump 4. This configuration is the same as that of a general SEM apparatus.

  As described above, in this embodiment, the sample stage 5 and its operation knob 108, operation knob 109, gas supply pipe 100, and pressure adjustment valve 104 are all attached to the lid member 122 in an integrated manner. Therefore, the apparatus user can perform the operation of the operation knob 108 and the operation knob 109, the sample replacement operation, or the detachment operation of the gas supply pipe 100 and the pressure adjustment valve 104 on the same surface of the first housing. Therefore, the operability is greatly improved as compared with a scanning electron microscope having a configuration in which the above-described components are separately attached to the other surfaces of the sample chamber.

<Sixth embodiment>
The sixth embodiment will be described. FIG. 6 shows an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the sixth embodiment. The sixth embodiment is different from the second embodiment in that the optical microscope is generally disposed outside the apparatus and the optical microscope barrel 200 of the holding portion 132A of the second housing 121 is opposed to the second embodiment. The window 215 is formed at the position where In the following description, the description overlapping with the second embodiment is omitted as much as possible.

  As shown in FIG. 6, in this embodiment, the lens barrel 200 and the light source 201 of the optical microscope are all arranged outside the apparatus, and a window 215 for allowing light to pass through at least the holding portion 132A of the second casing 121. Is configured.

Since a general optical microscope can be observed at a higher magnification when the distance between the objective lens and the sample is shorter, for example, as described in the first to fifth embodiments rather than the arrangement of the lens barrel 200 of the present embodiment, The configuration shown in FIGS. 1 to 5 is more preferable because the resolution of the optical microscope is higher. However, since the entire optical microscope can be arranged outside the apparatus (outside the second space 12) in the configuration of FIG. 6, it is possible to eliminate the trouble of blocking the second housing from the atmosphere with the sealing member 202 or the like. A simpler configuration can be obtained. When the sample 6 is a transparent material or a member that transmits light, the light source 201 may be disposed below the sample stage 5 as shown in FIG.

<Seventh embodiment>
The seventh embodiment will be described. FIG. 7 shows an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the seventh embodiment. The seventh embodiment is a modification of the second embodiment, and is different from the second embodiment in that the sample stage 5 as a sample mounting portion is generally replaced with the support plate 107 and the lens barrel 200. The sample stage moving mechanism 107A for moving between the optical axis 204 of the sample microscope and the optical axis 203 of the electron microscope, and the holding portion 132A of the second housing 121 are the optical axes of the lens barrel 200 of the sample stage 5. The second space 12 is configured to be large so that it can be moved to the 204 side.

  The sample stage moving mechanism 107A as the moving mechanism is configured to transmit and receive data to and from the lower control unit 37 via the communication line 43 by driving the sample stage moving mechanism 107A and moving the sample stage 5. . This moving mechanism detects light from the sample 6 by the first position where the primary charged particle beam irradiated from the charged particle optical column 2 on the sample stage 5 irradiates the sample 6 and the column 200 of the optical microscope. At least configured to be movable between the second position.

  After observing the sample 6 with the optical microscope, the sample stage 5 can be observed by the optical microscope and the electron microscope by moving the sample stage 5 by the above-mentioned predetermined distance by the sample stage moving mechanism 107A. Become.

  Further, unlike the configuration in which the optical microscope and the electron microscope are opposed to each other as described in the cited document 1, it is possible to observe the same part from substantially the same direction, and usability can be improved.

  In addition, as described above, the second housing 121 can be in an atmospheric atmosphere of 1 atm, a gas atmosphere, or a vacuum atmosphere, so that it can be observed alternately with an optical microscope and an electron microscope under various atmospheric conditions. It becomes.

  In addition, in this embodiment, it is applicable also to 3rd embodiment-6th embodiment mentioned above.

<Eighth embodiment>
The eighth embodiment will be described. FIG. 8 is an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the eighth embodiment. The eighth embodiment is a modification of the sixth embodiment. The difference from the sixth embodiment is that the holding portion 132A of the second housing 121 is generally integrated with the mating portion 132 ( Alternatively, the alignment unit 132 also serves as the function of the holding unit 132A) and the lens barrel 200 of the optical microscope includes a position adjustment mechanism 209 that moves in the perspective direction (vertical direction) with respect to the sample 6. . In the following description, the description overlapping with the sixth embodiment is omitted as much as possible. As shown in FIG. 8, the holding part 132A of the second housing 121 is integrated with the mating part 132, and the optical microscope (the lens barrel 200 and the light source 201) moves in the perspective direction (vertical direction) with respect to the sample 6. A position adjusting mechanism 209 is provided in the holding portion 132A. The position adjustment mechanism 209 includes a holding body 207 that holds the optical microscope, a support bar 208 that supports the holding body, and an adjustment unit 209A that can adjust the vertical position of the holding body 207 in the support bar 208. It is configured.

FIG. 9 shows a configuration in which the sample stage 5 is pulled out together with the lid member 122. After the sample stage 5 is pulled out, the position adjustment mechanism 209 is used to move the optical microscope closer to the sample 6 to a position where the sample 6 can be observed for observation. When closing the lid member 122, observation is possible by changing the optical microscope so that the position of the lower end is higher than the upper end of the lid member 122 using the position adjusting mechanism 209. In the case of this configuration, for example, a screw hole is provided in the mating portion 132 of the second housing 121, and the support rod 208 is attached to the screw hole, so that an optical microscope can be attached. By removing the optical microscope, the optical microscope can be detached, and the optical microscope can be easily attached and detached. Therefore, the structure of the second housing 121 can be very simple and simple compared to the configuration of the second embodiment. The optical microscope may be configured to be supported by the first housing 7 or may be configured to be supported by the lid member 122.

<Ninth Embodiment>
The ninth embodiment will be described. FIGS. 10 a and 10 b show an overall configuration diagram of an observation apparatus (inspection apparatus) as a charged particle microscope including the optical microscope according to the ninth embodiment. In the ninth embodiment, as shown in FIGS. 10a and 10b, the arrangement of the cover member 122 relative to the arrangement of the charged particle optical column 2 of the charged particle microscope and the column 200 of the optical microscope (movement of the sample stage 5) This is a configuration example in which the (direction) relationship is different from that of the above-described embodiment. The direction in which the sample stage 5 is removed from the direction in which the charged particle optical column 2 and the column 200 of the optical microscope are arranged is a horizontal direction and a vertical direction. The charged particle optical column 2 and the column 200 of the optical microscope are arranged in a direction opposite to the direction in which the sample stage 5 is attached to and detached from the second space 12.

  In the following description, the description overlapping with the above-described embodiment is omitted as much as possible. As shown in FIGS. 10a and 10b, the second casing 121 can dispose the thin film 10 in a state where the lid member 122 that holds the sample stage 5 is opened and the extraction port for taking out the sample stage 5 is opened. The configured second casing 121 is arranged so as to cover the lower side of the charged particle optical column 2. A sealing member 125 is provided between the upper end of the second housing 121 and the upper lower surface of the first housing 7. The first space 11 and the second space 12 are configured to be separated from each other by the second housing 121. Since the outlet for taking out the sample stage 5 is arranged so that the charged particle optical column 2 and the barrel 200 of the optical microscope face each other, the lid 122 is opened and the outlet for taking out the sample stage 5 is opened. In this state, the charged particle optical barrel 2 and the optical microscope barrel 200 can be easily maintained.

  The second housing 121 may be configured to be screwed to the first housing 7 from the lower side in the figure, or from the upper upper surface side of the first housing 7 to the first housing 7. You may comprise so that it may be screwed with respect to it.

The configurations shown in FIGS. 10 a and 10 b can enable observation with an electron microscope in a state in which the pressure in the second space 12 is higher than the pressure in the first space 11 simply by attaching the second housing 121. Preferably, the optical axis 204 of the optical microscope barrel 200 and the optical axis 203 of the charged particle optical barrel 2 are preferably provided in parallel. This makes it possible to further observe the same part from the same direction. Note that the optical axis 204 of the lens barrel 200 and the optical axis 203 of the electron microscope may be arranged obliquely as long as the same part can be observed from substantially the same direction.

  Moreover, even if it removes an optical microscope, it is good also as attachment or detachment so that observation with a charged particle microscope is possible.

  Preferably, as shown in FIGS. 10a and 10b, a housing 214 that forms the sample introduction chamber 210 may be provided. In this case, preferably, the sample stage 5 and the lid member 122 are always fixed, and the sample 6 can be transported from the sample introduction chamber 210 to the second space 12. As shown in FIG. 10 b, the sample introduction chamber 210 may include a door 211, a door 212, and a sample introduction rod 213. The optical microscope may be provided in the sample introduction chamber 210.

  Next, an operation when the sample introduction chamber 210 is arranged will be described.

  First, the door 211 is opened, and the sample 6 or the sample holder on which the sample 6 is mounted is placed in the sample introduction chamber 210. Thereafter, the door 211 is closed and the door 212 is opened. Then, the sample introduction rod 213 conveys the sample 6 or the sample holder on which the sample 6 is arranged onto the sample stage 5. Thereby, the sample 6 can be transported to the second space without removing the lid member 122 provided with the sample stage 5.

  As a feature of this configuration, when a light element gas or the like is contained in the second space 12 via the gas supply port 100, even if the sample 6 is replaced, the atmosphere is less likely to be mixed into the atmosphere in the second space 12. Thus, it is not necessary to introduce a large amount of light element gas with the replacement, and the amount and frequency of use of the gas can be greatly reduced.

0 charged particle source 1 optical lens 2 charged particle optical column 3 detector 4 vacuum pump 5 sample stage 6 sample 7 first housing 10 thin film 11 first space 12 second space 14 leak valve 16 vacuum pipe 18 column 19 lid member Support member 20 Bottom plate 35 Personal computer 36 Upper control unit 37 Lower control unit 43, 44 Communication line 47 Thin film holding member 100 Gas supply port 101 Gas control valve 102 Connection unit 103 Gas cylinder 104 Pressure adjustment valve 107 Support plate 108, 109 Operation knob 121 Second housing 122, 130 Lid member 123, 124, 125, 126, 128, 202 Sealing member 131 Main body part 132 Matching part 200 Lens tube 201 Light source 203, 204 Optical axis 205 Drive mechanism 206 Cavity part 207 Holder 208 Support rod 209 Position adjustment mechanism 210 Sample introduction chamber 211, 212 Door 213 Fee introduction rod 214 housing 215 window

Claims (3)

A sample observation method using a charged particle beam apparatus having a charged particle optical column that irradiates a charged particle beam, a vacuum chamber, and a sample chamber in which a sample is stored,
Maintaining the sample chamber at a higher pressure than the vacuum chamber by a thin film that transmits the charged particle beam;
Finding the relationship between the height of the lower surface of the thin film and the height of the lower end of the lens barrel of the optical microscope,
Measure the distance between the sample and the lens barrel,
Based on the relationship between the distance, setting the distance between the said thin film sample, the sample observation method. Between the second position when observing the sample by the first position and the optical microscope when the charged particle beam is irradiated to the sample, to move the sample placing portion for placing the sample, The sample observation method according to claim 1 . The charged particle beam apparatus has a sample placement unit for placing the sample,
The sample observation method according to claim 1, wherein observation with the charged particle beam device and observation with the optical microscope are performed on the sample in a state of being placed on the sample placement unit.

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