JP2010008141A - Solid sample making apparatus, solid sample making method and sample observing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a change in the composition or structure of a specimen in solidification by suppressing the evaporation of a liquid sample from a discharge port and to enable the stable discharge of the specimen. <P>SOLUTION: The solid sample making apparatus includes solid sample making chambers (1-3), a stage (14), a specimen supply device (16) equipped with a discharge port for discharging the specimen and supplying the specimen to the surface of the stage by discharge operation and a cooler (13) for cooling the stage. This solid sample making apparatus which supplies the specimen to the surface of the cooled stage in the solid sample making chamber to solidify it includes a suction device (18) sucking the specimen from the discharge port in the state that the discharge port of the specimen supply device is shielded from the atmosphere in the solid sample making chamber in standby of the discharge operation of the specimen supply device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solid sample preparation apparatus, a solid sample preparation method, and a sample observation method. More specifically, the present invention relates to a solid sample manufacturing apparatus, a manufacturing method, and an observation method capable of more accurately observing the dispersion state of a substance dispersed in a liquid that exhibits a liquid phase at normal temperature and pressure.

  With the recent increase in demand for functional devices, more accurate evaluation of the dispersion state and fine structure analysis are desired for specimens in which solid or liquid dispersions such as drugs and emulsions are dispersed in liquid.

  In order to observe a finer structure than a structure observable with an optical microscope, a scanning electron microscope (SEM) is generally used. However, since the sample is placed in a vacuum, a normal sample cannot be observed in a liquid state. Therefore, when observing a liquid sample as a specimen, it is necessary to fix the sample so that it does not change even in a vacuum. In addition to SEM observation, when a liquid sample to be observed is observed in a stationary state, the liquid sample must be fixed by some method.

  One method for observing the dispersion in a liquid sample while maintaining the distribution density and aggregation / dispersion state in the liquid is a method in which the liquid sample is frozen and solidified. When a liquid sample is frozen, solidification may proceed while the crystallization surface moves in the sample. In this case, since the dispersion moves in the liquid medium as the crystal plane moves, the dispersion state of the dispersion in the solidified sample is different from the dispersion state in the liquid before freezing. The object cannot be observed accurately.

  Patent Document 1 proposes a method in which a liquid sample is put in a sample holder, and the sample holder is pressed onto a cooled metal block to rapidly cool the sample holder. However, when observing the sample, it is necessary to remove the sample from the holder and move it to the stage of the processing / observation apparatus. In addition, when the sample is very small, it is difficult to make the heat capacity of the holder smaller than the heat capacity of the sample. Therefore, the cooling condition of the sample varies depending on the heat capacity of the holder, and a frozen sample with a uniform entire sample to be observed can be obtained. Can not.

  Patent Document 2 discloses a method in which a sample is rapidly cooled and frozen and solidified immediately after the sample is irradiated with microwaves. In the conventional quick freezing apparatus, since the region where water becomes amorphous and is frozen is limited to a very small portion of about 20 μm from the surface in contact with the copper block, in Patent Document 2, a microwave is used. ing.

  As described above, Patent Document 2 discloses that microwave irradiation prevents the growth of ice crystals and greatly expands the region that is frozen amorphous.

  However, in the above-described method, energy is given from outside the sample by the microwave and an artificial dispersion state is formed, so that the obtained solid sample is different from the dispersion state in the original liquid sample. In addition, the entire sample has not yet been made an amorphous solid.

  In any case, as described above, when observing the sample, it is necessary to remove the sample from the holder and move it to the stage of the processing / observation apparatus. In addition, when the sample is very small, it is difficult to make the heat capacity of the holder smaller than the heat capacity of the sample. Therefore, the cooling condition of the sample varies depending on the heat capacity of the holder, and a solid sample with a uniform entire sample to be observed can be obtained. Can not.

  The main method of obtaining information about the sample is to obtain average information using electromagnetic scattering such as light scattering method and small-angle X-ray scattering method, after creating a cross section by freezing cleaving method, cryomicrotome method, etc. The method etc. which observe with an optical microscope are mentioned.

  Recently, a FIB-SEM apparatus has been developed in which a processing function using a focused ion beam (FIB) apparatus is added to the SEM apparatus. The FIB apparatus is an apparatus that performs processing by etching or the like by finely focusing an ion beam from an ion source and irradiating a processing sample.

  Patent Document 3 proposes a technique in which a sample temperature is adjusted during FIB processing and SEM observation to prevent structural change and beam damage due to temperature rise and to accurately analyze the cross-sectional structure of the sample. .

Further, Patent Document 4 proposes a method in which a temperature-controlled sample is created with a cover after cross-section creation, and it is possible to transfer to another apparatus and evaluate a predetermined portion.
Japanese Utility Model Publication No. 57-75554 Japanese Patent Publication No. 08-12136 Japanese Patent No. 3715956 JP 2005-148003 A

  FIG. 10 is a schematic configuration diagram of a solid sample manufacturing apparatus previously proposed by the present inventor.

  The introduction rod 202a and the operation unit 202b constitute a moving mechanism for moving the stage, and the stage 201 can be moved and fixed to an arbitrary position.

  A chamber hatch 203b is provided in the first chamber 203a, and the space of the first chamber can be isolated while maintaining airtightness.

  203d is a purge gas inlet, 203c is a purge gas on-off valve, and 203e is an O-ring for sealing a portion in contact with the second chamber 204a.

  A chamber hatch 204d is provided in the second chamber 204a, and a purge gas introduction port 204c is attached via a purge gas opening / closing valve 204b. The second chamber 204a is connected to the leak port 204f and the vacuum pump 205 via the switching valve 204e.

  In the second chamber 204a, a cooler 206 for the sample stage 201 and a specimen supplier 207 are provided. The sample supply unit 207 is a liquid ejecting head that ejects a liquid sample into droplets and ejects the sample toward the stage 201 at a predetermined speed.

  The specimen supplier 207 discharges liquid from the discharge port under the control of the discharge control device 208 to form flying droplets. The droplets are solidified on the cooled surface of the stage to produce a solid sample.

  However, it has been found that depending on the type of the sample, at least a part of the liquid evaporates from the sample supply device 207, thereby changing from the original state of the sample. As a result, the composition and structure of the solid sample obtained may change from the original composition and structure of the specimen.

  An object of the present invention is to suppress the evaporation of a liquid sample from the discharge port of a sample supply device, to suppress changes in the composition and structure of the sample when solidified, and to enable stable sample discharge. It is in.

The first outline of the present invention is:
A solid sample preparation room;
Stage,
A sample supply device that includes a discharge port for discharging the sample, and supplies the sample to the surface of the stage by a discharge operation;
A cooler for cooling the stage;
Have
In the preparation chamber of the solid sample for supplying the specimen to the cooled surface of the stage and solidifying the specimen in the preparation chamber,
The sample supply device includes an aspirator that sucks the sample from the discharge port in a state where the discharge port of the sample supply device is shielded from the atmosphere in the manufacturing chamber when waiting for the discharge operation of the sample supply device.

The second gist of the present invention is a method for producing a solid sample,
A step of preparing the above-described solid sample manufacturing apparatus;
An introducing step of introducing a dry gas into the production chamber;
A cooling step for cooling the stage;
Performing a discharge operation of the specimen supply device in the fabrication chamber;
A suction step of sucking the sample from the discharge port in a state where the discharge port of the sample supply unit is shielded from the atmosphere made of the dry gas in the manufacturing chamber when waiting for the discharge operation of the sample supply unit;
It is characterized by having.

The third aspect of the present invention is a sample observation method,
Producing a solid sample using the solid sample production method described above;
An observation step of observing a cross section of the solid sample while maintaining the amorphous state of the solid sample;
It is characterized by including.

  According to the present invention, it is possible to suppress the evaporation of the sample from the discharge port of the sample supply device, and to suppress changes in the composition and structure of the sample. In addition, even if a change in composition or structure occurs in the specimen near the discharge port, the portion can be removed by suction, so that a solid sample reflecting the composition or structure in the liquid phase of the specimen can be produced.

(Embodiment 1)
(Solid sample preparation equipment)
FIG. 1 is a schematic configuration diagram of an apparatus for preparing a solid sample according to an embodiment of the present invention.

  The sample preparation chamber is roughly divided into a first chamber 1, a second chamber 2, and a third chamber 3. The manufacturing chamber isolates the atmosphere in the first chamber from the atmosphere in the second chamber, and at least two openable shutters 4 that isolate the atmosphere in the second chamber and the atmosphere in the third chamber. 5

  The stage 14 is attached to the introduction rod 15 and pressed against the cooler 13 by a leaf spring (not shown). The material of the stage 14 is desirably made of a material having high specific heat and high thermal conductivity, specifically, a metal such as aluminum or copper. A thin aluminum oxide film may be formed on the surface.

  Here, the stage 14 and the introduction rod 15 are attached to each other by screws, and the introduction rod 15 can be separated and coupled with the stage 14 by turning the introduction rod 15. A temperature sensor (not shown) is incorporated in the stage 1 as required, and can be connected to a temperature display unit or a temperature control device (not shown) installed outside through the introduction rod 15.

  The introduction rod 15 passes through a through hole (not shown) provided in the sealable third chamber 3 via an O-ring (not shown), and can be slid in an airtight state. By sliding the introduction rod 15, the stage 14 can be moved to the specimen supply position in the first chamber.

  The third chamber 3 is provided with a shutter 5 that can be opened and closed, and can be isolated while maintaining the airtightness of the space in the third chamber 3. Further, the third chamber 3 is provided with an O-ring (not shown) for sealing a portion in contact with the second chamber 2 adjacent to the third chamber 3.

  The sample preparation chamber has a third chamber 3 for accommodating the stage 14, and the third chamber 3 is provided with a chamber moving mechanism if necessary, and can be separated from the second chamber. It is configured. The second chamber 2 and the third chamber 3 are configured to have the same atmosphere.

  A gas pipe (not shown) is connected to the purge gas introduction valve 10, and the second chamber 2 that can be sealed fills the second chamber 2 with a gas containing no moisture such as nitrogen through the gas introduction valve 10. be able to.

  An openable / closable shutter 4 is provided between the first chamber 1 and the second chamber 2, and the space between the first chamber 1 and the second chamber 2 can be isolated by controlling the atmosphere individually. The second chamber 2 is connected to the vacuum pump 6 and the atmosphere via a gas discharge valve 8, and these connections can be switched.

  A dewar bottle 11 into which a necessary amount of refrigerant has been injected is connected to a cooler 13 which is a temperature adjusting means of the stage 14 by a temperature transmission unit 12. The material of the temperature transfer part 12 is preferably a substance having a high thermal conductivity, for example, a metal such as copper. The Dewar bottle 11 may be installed either outside or inside the second chamber 2. Liquid nitrogen or liquid helium can be used as the refrigerant.

  In addition, the cooler 13 incorporates a heater and a temperature sensor (not shown) as needed, and is connected to a temperature display unit or a temperature control device (not shown) installed outside to control a desired temperature. it can. Moreover, the cooler 13 may incorporate a cooling mechanism such as a Peltier element or a helium refrigerator.

  A gas pipe (not shown) is connected to the purge gas introduction valve 9, and the first chamber 1 that can be sealed is dried without containing moisture such as nitrogen through the gas introduction valve 9. Can be filled with gas. Further, the gas in the first chamber 1 can be discharged out of the chamber through the gas discharge valve 7.

  In the first chamber 1, for example, a liquid ejecting head is provided as the specimen supplier 16.

  The liquid ejecting head is provided with at least one ejection port for ejecting liquid.

  The sample supplier 16 is connected to a control device (not shown), and ejects droplets by an ejection operation under an arbitrary condition.

  The cap 17 as a shielding member shields the discharge port of the sample supply device from the atmosphere in the production chamber when the sample supply device 16 is waiting for the discharge operation. An aspirator 18 for aspirating a sample from the discharge port in a state where the discharge port is shielded is provided. The cap 17 is disposed in the vicinity of the discharge port of the sample supply device 16 in the head standby state. The function of the cap 17 is not only to suppress changes in the composition and structure of the specimen, but also to prevent the discharge port from being dried and to prevent contamination by the specimen in the chamber.

  A sample aspirating unit 18 is connected to the cap 17, and not only can the clogging be recovered by reducing the pressure inside the cap 17 and aspirating the sample from the sample supply device 16, but also removing the altered sample. Can do.

  The cap used in the present invention may be any cap as long as it can shield the ejection port of the head from the atmosphere in the production chamber during standby of the ejection operation of the head as the specimen supply device, and those having various shapes are preferably used. The material of the cap may be made of an elastic body such as silicone rubber, or only the contact portion to the head may be made of an elastic body, and the cap body may be made of an inelastic body such as metal, ceramics, or plastic.

  Natural rubber or synthetic rubber is used as the elastic body. Synthetic rubbers include styrene butadiene rubber (SBR), polybutadiene rubber (BR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), ethylene propylene rubber (EPDM), epichlorohydrin rubber (CHR), chloro Examples thereof include sulfonated polyethylene (CSM), acrylic rubber, silicone rubber, fluorine rubber, and urethane rubber.

  Any aspirator may be used as long as the sample can be sucked from the discharge port while the discharge port is shielded from the atmosphere in the manufacturing chamber. Specifically, the pump may be a reciprocating pump such as a piston pump, a plunger pump, or a diaphragm pump, or a rotary pump such as a gear pump, a vane pump, or a tube pump.

The first chamber 1 and the sample supply device 16 are connected via a moving mechanism 20 in the horizontal direction in the drawing and a moving mechanism 21 in the vertical direction in the drawing. The moving mechanism 20 and the moving mechanism 21 are connected to a moving mechanism control unit (not shown) and can move the sample supply device 16 to a preset position.
It is also possible to move the cap 17 up and down instead of the vertical movement mechanism 21 in the figure.

  By operating the moving mechanism 21, it is possible to control the appropriate distance from the stage 14 at the same time that the sample supplier 16 is separated from the cap 17. Further, by operating the moving mechanism 20, the specimen supply device 16 is moved from the first chamber 1 to the vicinity of the stage in the second chamber 2, the specimen is discharged, and the formed flying droplets are placed on the stage surface. Adhere to.

  As described above, in order to execute the discharge operation of the sample supply device 16, the sample supply device moving mechanism 20 that moves the sample supply device 16 from the first chamber 1 to the second chamber 2 is provided. Further, in order to take out the solid sample, a stage moving mechanism 15 for moving the stage 14 from the second chamber 2 to the third chamber 3 is provided.

  The solid sample preparation chamber includes a first chamber 1 provided with an aspirator and a second chamber 2 provided with a cooler 13. In the second chamber 2, a discharge operation of the specimen supply device is performed. Is executed. In the present invention, the discharge operation may be performed in the first chamber 1 as will be described later.

(Solid sample)
In the solid sample produced by the solid sample production method of the present invention, the entire region to be observed is solidified in an amorphous state. An amorphous solid is a solid obtained by freezing a random molecular arrangement of a liquid as it is, and can be obtained by rapidly cooling a specimen droplet made of a liquid sample to inhibit crystal growth.

  When the dispersion is dispersed in the liquid sample, crystal plane growth does not occur by solidifying in an amorphous state, and therefore, the dispersion does not move along with the crystal plane growth. Moreover, since the sample is not irradiated with microwave energy before solidification, the obtained solid sample correctly reflects the dispersion state of the dispersion in the liquid state, and when observing the solid sample with SEM or the like, Accurate distribution observation of the dispersion in the liquid state can be performed.

  Whether the solid sample is amorphous can be determined from direct observation using an optical microscope, SEM, laser microscope, or the like, and measurement of a diffraction pattern using a transmission electron microscope or X-ray analysis. When a crystalline part is present in part, a certain block of crystals can be directly observed with a scanning electron microscope, and a diffraction pattern derived from the crystalline part can be obtained with a transmission electron microscope and X-ray analysis. Besides this, it is possible to identify amorphous or crystalline by Raman spectroscopy.

  The amorphous state of the solid sample of the present invention refers to a state in which crystals having a particle size of 10 nm or more are not observed by SEM, for example.

  The liquid (A) that exhibits a liquid phase at room temperature and normal pressure used in the present invention is, for example, a liquid that exhibits a liquid phase at room temperature of 1 atm and about 20 ° C., and is typically water or a water-soluble solvent. And organic solvents.

  Examples of the organic solvent used in the present invention include alcohols such as ethanol, methanol, and isopropanol; polyhydric alcohols such as glycerin and polyethylene glycol; acetone; ethyl ether; xylene; cyclohexane;

  As the substance (B) exhibiting a solid phase or a liquid phase at room temperature and normal pressure used in the present invention, for example, a substance exhibiting a solid phase or a liquid phase at room temperature of about 1 ° C. and about 20 ° C. is used.

  Examples of the substance (B1) that exhibits a solid phase at normal temperature and pressure include pure metals or alloys such as gold, silver, and copper, semiconductors such as silicon and germanium, silicon oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. And inorganic fine particles such as carbon black and the like. Or organic particulates, such as organic compounds, such as anthraquinone derivative and a polystyrene resin; Metal complexes, such as copper phthalocyanine, may be sufficient.

  The particle size of the substance (B1) is not particularly limited as long as the dispersibility in the liquid is maintained, but is 10 nm or more and 1 μm or less, more preferably 10 nm or more and 100 nm or less.

  These particle diameters can be measured by a method such as a light scattering method or a laser diffraction method.

  The substance (B2) that exhibits a liquid phase at room temperature and normal pressure is not particularly limited as long as it is a substance that exhibits a liquid at room temperature and becomes a solid together with the liquid (A) by rapid cooling. However, the substance (B2) needs to be a substance that can be dispersed in the liquid (A).

  Specifically, the substance (B2) is a liquid in an emulsion state, and examples thereof include a protein dispersion and an unreacted emulsion polymerization liquid. The particle diameter of the liquid substance (B2) can be appropriately selected from the range of 10 nm to 1 μm, more preferably 10 nm to 100 nm.

  These particle sizes can be measured by a method such as a light scattering method.

  The function of the substance (B) that exhibits a solid phase or a liquid phase at room temperature and normal pressure may be a pigment, a color material, a conductive substance, an insulating substance, a semiconductor, a dielectric, a magnetic substance, an emulsion, a surfactant, and the like. .

  Moreover, as the substance (B), for example, a substance having a freezing point of −40 ° C. or higher, for example, a substance having a freezing point selected from the range of −40 ° C. or higher and + 20 ° C. or lower is preferably used. Specific examples of these include vegetable oil and fat, cyclohexane, and the like.

  The liquid sample (AB) as a specimen used in the present invention includes, for example, a pigment ink composition in which a pigment is dispersed, and a conductive paste composition in which silver particles are dispersed in an organic solvent in which a thermosetting resin is dissolved. And a solution in which chargeable particles are dispersed.

(Preparation method of solid sample)
In the solid sample preparation method of the present invention, the stage is cooled in advance, and a specimen droplet having a predetermined volume within a range that can be made amorphous is ejected from the ejection device, and the droplet is landed on the stage. Is rapidly cooled and solidified in an amorphous state.

  The solidification step for solidification is desirably performed in a dry gas atmosphere. Thus, when the droplets are rapidly agglomerated and solidified, the occurrence of condensation on the sample surface can be suppressed.

  A dry gas atmosphere within a range of −273 to −196 ° C., which is lower than the stage temperature set by the dew point, is preferable.

  The dry gas is not particularly defined as long as it has a low moisture content, and is preferably a gas containing at least one of a rare gas such as helium and argon, or an inert gas selected from nitrogen. It may be a reactive gas.

  Hereinafter, each step will be described.

  First, the stage which becomes the landing point of the liquid (A) containing the substance (B), that is, the droplet of the liquid sample (AB) as the specimen is cooled.

  The stage is a sample stage for condensing and solidifying the liquid sample (AB), and is precooled by a cooler capable of cooling the stage.

  The stage used in the present invention only needs to have a thermal conductivity sufficient for the droplets to freeze in a short time to become an amorphous solid sample. For example, aluminum, aluminum alloy, copper, copper alloy The member which has the surface which consists of such a metal material is mentioned. Alternatively, a thin insulating film such as a metal oxide may be formed on the surface of the metal material.

  The cooler for cooling the stage may be, for example, a Dewar bottle containing a refrigerant such as liquid nitrogen or a cooling chamber kept at a low temperature. Further, a cooling mechanism such as a metal block cooled to a low temperature, a Peltier element, or a helium refrigerator may be used.

  If the cooling temperature of the stage is liquid nitrogen temperature (-196 ° C), when the droplet of the liquid sample (AB) reaches the stage, the droplet is rapidly cooled, and the entire sample to be observed forms a crystal part. It becomes amorphous without doing.

  Even when liquid nitrogen is not used for cooling, for example, when the liquid is water, the glass transition point of water at 1 atm is approximately −130 ° C., so that if the stage temperature is approximately −140 ° C. or less, an amorphous solid sample Is obtained.

  Next, the liquid sample (AB) is discharged from the specimen supply device as droplets having a size within a range where the entire region to be observed can be amorphized, and is landed on a stage cooled in advance by a cooler.

  The stage used in the present invention is provided with a moving mechanism for moving the surface in a direction crossing the droplet discharge direction so that a plurality of droplets are attached to the surface of the stage separately from each other. It is preferable. In this way, a plurality of amorphized solid samples are obtained.

  Specifically, it is preferable that the stage is movable in a direction intersecting the droplet discharge direction, more specifically in a vertical direction. By moving the stage in a direction perpendicular to the discharge direction during droplet discharge, a plurality of solid samples having substantially the same shape and the same size can be obtained.

  In addition, since the stage is configured to be separable from the cooler, the stage can be cooled by the cooler in advance, and then the stage can be moved freely so that a plurality of droplets can land on any position.

It is more preferable to make the entire droplet landed on the stage amorphous by adjusting the viscosity, flight speed, volume, and flight distance of the droplet.
Note that the thickness of the thin film formed from the droplets need not be uniform.

  By causing the droplets to collide toward the stage at a high speed, the droplets spread on the stage to form a thin film, and then cooled.

  In the present invention, it is preferable that droplets are landed on the stage at a volume of 100 pl (picoliter) or less and at a flight speed of 5 m / second or more. For example, the volume of the droplet is 10 pl (picoliter) and the flying speed of the droplet is 7 m / sec.

  By sufficiently reducing the thickness of the coating, heat transfer to the stage occurs in a short time. For this reason, the liquid molecules in the droplet-like sample (AB) are almost instantaneously solidified, but the substance (B) which is a dispersion much larger than the molecules is spatially within the time when the liquid (A) is solidified. It is difficult to move.

As a result, the dispersed state of the substance (B) is maintained and fixed as it is. In the case of an aqueous liquid, the liquid sample (AB) preferably has a surface tension of 70 mN / m or less and a viscosity of 1 × 10 ⁻² Pa · s or less for forming a thin film on the stage.

  It should be noted that the thickness of the thin film of droplets landed on the stage can be selected from the range of 1 μm to 50 μm, more preferably 1 μm to 10 μm. Within this range, a solid sample consisting entirely of an amorphous solid can be easily formed. Further, unlike the prior art, the whole can be made amorphous even in an observation region having a size in the range of 25 μm or more and 50 μm or less exceeding 20 μm from the landing surface.

  When the volume of the droplet is large, it does not become a thin film on the stage, but adheres as a raised droplet with a large contact angle. At this time, since the volume of the liquid is larger than the contact area with the stage and it takes time to move the heat, the particles move in the liquid during the cooling process and the dispersion state changes.

Further, even a droplet having a small volume may not be a sufficiently thin film on the stage if the flying speed is low. At this time, even if the amount of liquid is small, the dispersion state is likely to change. Usually, it is preferable from the viewpoint of uniform thin film formation that the droplet volume is suitably adjusted in the range of 0.1 pl to 1 nl and the flying speed in the range of 3 m · s ^{−1 to} 20 m · s ⁻¹ .

  As the sample supply device used in the present invention, a liquid ejecting head that discharges liquid and forms flying droplets is preferably used. This liquid ejecting head ejects droplets from nozzles (ejection ports), and is called a so-called inkjet head.

  In the present invention, the liquid to be ejected is not limited to ink in a narrow sense even though it is ink jet.

  The ink jet head is suitable for forming minute droplets and can adjust the volume and flying speed of the droplets, and is therefore suitable for the production of the solid sample of the present invention. As the ink jet head, any system such as a thermal system, a piezo system, an electrostatic system, or the like can be used.

  As a sample supply device used in the present invention, a micropipette, a hollow tube such as a capillary tube, or the like can be used in addition to the liquid ejecting head.

  Further, the stage may move with respect to the cooler, and the droplet may land on the stage after the stage leaves the cooler. The solidification heat generated when the landed droplets solidify is sufficiently small compared to the heat capacity of the stage, so that the entire droplet can be made amorphous even after landing on the stage after the metal stage leaves the cooler .

In short, a method for preparing a solid sample in a preferred embodiment of the present invention is as follows.
Preparing a solid sample preparation apparatus as described above and below;
An introduction step of introducing dry gas into the fabrication chamber;
A cooling process for cooling the stage;
A step of performing a discharge operation of the specimen supply device in the manufacturing chamber;
A suction step of sucking the sample from the discharge port in a state where the discharge port of the sample supply device is shielded from the atmosphere made of dry gas in the production chamber when waiting for the discharge operation of the sample supply device;
It is characterized by having.

  More preferably, the specimen includes a liquid that exhibits a liquid phase at normal temperature and pressure, and a substance that is different from the liquid and exhibits a solid phase or a liquid phase at normal temperature and pressure, and the substance is contained in the liquid. It is advisable to prepare a sample dispersed in the sample, attach the sample as droplets to the cooled stage surface, and make the entire region to be observed amorphous.

(Sample observation method)
A sample observation method according to an embodiment of the present invention includes:
A step of producing a solid sample using the method of producing the sample;
An observation step of performing cross-sectional observation of the solid sample;
including.

  In the present invention, a temperature maintaining mechanism may be provided on the stage as necessary so that the temperature of the solid sample does not change during the movement of the stage.

  When processing / observation, the stage on which the solid sample is placed may be moved from the solid sample preparation device to the processing device or the processing / observation device to perform processing and / or observation as necessary. It is preferable.

(Preparation method of solid sample)
FIG. 2 is a flowchart showing one procedure of a solid sample manufacturing method using the manufacturing apparatus shown in FIG.

  3 to 6 are schematic diagrams for explaining the operation of each part in the solid sample preparation method by the solid sample preparation apparatus shown in FIG.

  Hereinafter, a procedure for preparing a solid sample will be described with reference to FIGS.

  First, a procedure (step S1) of replacing the space closed from the outside in the first chamber 1 with nitrogen gas will be described.

  First, the shutter 4 between the first chamber 1 and the second chamber 2 is closed, and the atmospheres in the first and second chambers are separated from each other.

  Then, the gas discharge valve 7 and the gas introduction valve 9 are opened, and the gas in the first chamber 1 is replaced with the dry nitrogen gas introduced from the gas introduction valve 9. The time for replacement with the dry gas here is not limited, but it is necessary to perform gas replacement for a sufficient time to achieve the above dew point until the water in the first chamber 1 can be completely removed. is there. In this way, it is possible to prevent dew condensation on the sample supply device, the sample, and further the solid sample.

  Next, the dewar bottle 11 is filled with liquid nitrogen (step S2).

  Then, the stage 14 is attached to the introduction rod 15 (step S3).

  Further, the stage 14 is moved and accommodated in the third chamber 3 by operating the introduction rod 15 (step S4). Then, the shutter 5 is closed.

  The integrated stage 14 and the opening of the third chamber 3 are installed and coupled to a position that seals the opening of the second chamber 2 via an O-ring (not shown) (step S5). Then, the shutter 5 is opened so that the second and third chambers communicate with each other.

  FIG. 3 shows a state where the above procedure is completed.

  Next, a procedure (step S6) of replacing the space closed from the outside in the second chamber 2 and the third chamber 3 with dry nitrogen gas will be described.

  The simplest procedure is to open the gas discharge valve 8 so as to be connected to the atmosphere and open the gas introduction valve 10 to allow nitrogen gas to flow in. However, sufficient nitrogen gas replacement is not performed due to gas stagnation or the like. The following method is preferred.

  First, the gas introduction valve 10 is closed, the gas discharge valve 8 is switched to conduct to the vacuum pump 6, the vacuum pump 6 is operated to discharge the gas in the chamber, and then the gas discharge valve 8 is closed. Then, the gas introduction valve 10 is opened and nitrogen gas is introduced. More preferably, the above-described evacuation and gas introduction are repeated several times.

  After the inside of the second chamber 2 and the third chamber 3 is replaced with nitrogen, the introduction rod 15 is operated to move the stage 14 onto the cooler 13 (step S7). This state is shown in FIG.

  If the temperature of the stage 14 is a liquid nitrogen temperature (−196 ° C.), when the droplet of the liquid sample lands on the stage, the droplet is rapidly cooled, and the whole is amorphous without forming a crystal part. A solid sample can be obtained. Even when liquid nitrogen is not used for cooling, an amorphous solid sample of an aqueous solvent sample can be obtained if it is −140 ° C. or lower.

  Then, if necessary, the heater of the cooler 13 is operated to stabilize the temperature of the stage 14 at a predetermined temperature (step S8). For example, in the case of a sample containing an aqueous solvent, the temperature of the stage 14 is set to −100 ° C., for example. Since this temperature is higher than the glass transition point of water -130 ° C, the sample becomes a crystallized solid sample.

  On the other hand, when it is frozen at the liquid nitrogen temperature (−196 ° C.), the difference between the dispersed state of the particles in the crystallized state and the amorphous state can be confirmed by comparing the solid sample.

  Next, the recovery procedure (step S9) of the sample supply device 16 will be described.

  When waiting for the discharge operation, the specimen supply device 16 is covered with a cap 17 in order to prevent evaporation of the sample liquid. However, for example, in the case of an inkjet head having a fine structure, normal ejection may not be possible due to evaporation of a small amount of liquid in the nozzle portion when left for a long time. Therefore, the sample is sucked from the discharge port of the sample supply device 16 by operating the sample suction unit 18 connected to the cap 17 via a tube and communicating with the inside of the cap 17 via the inside of the tube. As a result, the discharge port of the specimen supply device 16 is filled with the original normal sample.

  Subsequently, the shutter 4 is opened, the moving mechanism 21 is operated, and the sample supplier 16 is separated from the cap 17. At this time, the moving amount of the moving mechanism 21 is controlled so that the distance between the specimen supply device 16 and the stage 14 is 0.1 mm to 3 mm with respect to the sample discharge direction.

  Next, the moving mechanism 20 is operated to move the sample supply unit 16 onto the sample receiving unit 19 and discharge the sample from the sample supply unit 16. By preliminarily discharging the sample to the sample receiving unit 19, the discharge from the specimen supply device 16 can be further stabilized.

  Further, the moving mechanism 20 is operated to move the sample supply device 16 onto the stage 14, discharge the sample from the sample supply device 16 (step S 10), and attach the droplet of the sample to the stage 14. The adhered sample droplets are deprived of heat by the stage 14 and solidified (step S11).

  This state is shown in FIG.

  At this time, the sample can be attached in a fixed state without moving the specimen supply device 16. In addition, by attaching a sample (droplet) while moving the specimen supply device 16, it is possible to draw a pattern composed of a plurality of arbitrary droplets on the stage 14.

  In addition, in a state where the sample supply device 16 is fixed, the sample can be attached while operating the introduction rod 15 and moving the stage 14. Furthermore, a method of attaching the sample while moving both the specimen supply device 16 and the stage 14 may be used.

  Then, the moving mechanism 20 and the moving mechanism 21 are operated, and the sample supply device 16 is covered with the cap 17 to prevent the liquid from the sample supply device 16 from evaporating.

  Since the atmosphere in the first chamber 1, the second chamber 2, and the third chamber 3 is controlled with dry nitrogen gas, moisture does not condense on the solidified sample.

  A procedure for transferring the stage 14 to which the sample is fixed to the analyzer will be described below.

  First, the shutter 4 is closed (step S12), the gas introduction valve 10 is closed, the gas discharge valve 8 is switched to the vacuum pump 6, the vacuum pump 6 is operated, and the first chamber 1 and the third chamber 3 are evacuated. Exhaust is performed (step S13).

  Next, after the insides of the second chamber 2 and the third chamber 3 are sufficiently evacuated, the stage 14 is moved into the third chamber 3 by operating the introduction rod 15 (step S14).

  This state is the same as in FIG.

  Then, the shutter 5 is closed (step S15), the gas discharge valve 8 is closed, the gas introduction valve 10 is opened, and the inside of the second chamber 2 is purged with nitrogen gas to atmospheric pressure (step S16). Then, the second chamber 2 and the third chamber 3 are separated (step S17). This state is shown in FIG.

  Since the sample adhering to the stage 14 is sufficiently cooled, it does not vaporize and disappear.

  The separated opening of the third chamber 3 is connected to a sample introduction mechanism of an analyzer (not shown) via an O-ring (not shown), the shutter 5 is opened, the introduction rod 15 is operated, and the stage 14 is It transfers in the vacuum container of an analyzer (step S18).

  Furthermore, only the stage 14 can be accommodated in the vacuum vessel by operating the introduction rod 15 to separate the stage 14 and the introduction rod 15.

  According to the above procedure, the evaporation of the liquid sample in the specimen supply device is suppressed and solidified, whereby the change in the internal structure of the sample can be prevented and analysis can be performed with a desired analyzer. For example, a cross section of a sample solidified with a FIB-SEM apparatus as an analysis apparatus can be created, and the state of the cross section can be observed.

  In addition, since the recovery operation is performed by sucking the sample supply by the sample suction portion before discharging the sample from the sample supply, it is possible to discharge the liquid sample stably without clogging.

(Embodiment 2)
A solid sample preparation apparatus, a solid sample preparation method, and a sample observation method according to another embodiment of the present invention will be described.

(Solid sample preparation equipment)
FIG. 7 is a schematic configuration diagram in the case where the specimen supply device of the solid sample preparation apparatus is an inkjet head.

  Below, it demonstrates with reference to drawings centering around difference with Embodiment 1. FIG.

  The sample supply unit 16 is fixed to the first chamber 1 and is assembled so that the distance between the sample supply unit 16 and the stage 14 is 0.1 mm to 3 mm with respect to the discharge direction of the sample.

  Further, a moving mechanism 31 in the vertical direction in the drawing is connected to the cap 17 and can be controlled so as to switch between a contact state with the sample supply device 16 and a non-contact state from the outside.

  Further, the introduction rod 15 is in contact with a moving mechanism 30 in the horizontal direction in the figure, and can be moved between the cooler 13 and the sample supply device 16 at an arbitrary speed by a movement control means (not shown). it can.

  In short, the stage 14 is moved from the second chamber 2 to the first chamber 1 and the stage 14 is moved from the first chamber 1 to the third chamber 3 in order to take out the solid sample in order to execute the discharge operation of the specimen supplier 16. A stage moving mechanism for moving the stage.

  In the present embodiment, the method of moving the stage 14 by driving the introduction rod 15 has been described. However, the cooler 13 may be moved below the sample supply device 16 while the stage 14 is fixed to the cooler 13. It doesn't matter.

  Other than the above, the solid sample production apparatus of the present embodiment is the same as that of the first embodiment, and a detailed description thereof will be omitted.

(Preparation method of solid sample)
FIG. 8 is a flowchart showing a procedure of a solid sample preparation method using the solid sample preparation apparatus shown in FIG. 7, and FIG. 9 shows a sample of the specimen sample preparation method by the specimen sample preparation apparatus shown in FIG. It is the schematic which shows one procedure which adheres to a stage and solidifies.

  The recovery operation (step S9) of the specimen supply from the atmosphere control (step S1) in the second chamber of FIG. 8 is the same as the procedure of FIG. 2, and detailed description thereof is omitted.

  After step S <b> 9, first, the shutter 4 is opened, the moving mechanism 31 is operated, and the sample supplier 16 is separated from the cap 17.

  Next, a sample (droplet) is preliminarily discharged from the specimen supply device 16 into the cap 17 as necessary.

  Further, the moving mechanism 30 is operated to move the stage 14 onto the sample supply device 16 (step S101), and the sample supply device 16 is caused to perform a discharge operation so that the sample is discharged from the sample supply device 16, and the sample liquid is discharged. Drops are deposited on the stage 14. The attached sample is deprived of heat by the stage 14 and is solidified (step S102).

  This state is shown in FIG.

  At this time, the sample can be attached to the stage 14 with the sample supply 16 fixed, but by attaching the sample while moving the sample supply 16, a pattern composed of a plurality of droplets on the stage 14. Can also be drawn.

  And the moving mechanism 30 is operated, the stage 14 is moved on the cooler 13, and the temperature of the stage 14 is controlled to -190 degreeC. Further, the moving mechanism 31 is operated to cover the sample supply device 16 with the cap 17 to prevent evaporation of the liquid from the sample supply device 16.

  The first chamber 1, the second chamber 2, and the third chamber 3 are in a dry nitrogen gas atmosphere to prevent condensation.

  Transfer from the shutter closing (step S12) to the third chamber analyzer (step S18) in FIG. 8 is the same as in the first embodiment, and a detailed description thereof is omitted.

  By suppressing the evaporation of the liquid sample in the specimen supply device by the above procedure, it is possible to prevent the internal structure of the solidified sample from being altered with respect to the original internal structure of the specimen.

  In addition, since the recovery operation is performed by sucking the sample supply by the sample suction portion before discharging the sample from the sample supply, it is possible to discharge the liquid sample stably without clogging.

Example 1
The apparatus shown in FIG. 1 was prepared, and a solid sample was prepared according to the procedure shown in FIG. After step S18, a cross section of the solid sample was created by FIB-SEM, and the cross section was analyzed. As a result, it was observed that the solid sample was in an amorphous state in which pigment particles having a particle size of 30 to 80 nm were uniformly dispersed in the solidified solution.

(Example 2)
In the apparatus shown in FIG. 1, a hollow cylinder is attached as the specimen supplier 16 instead of the liquid jet head.

  This hollow cylinder was a Taber-shaped hollow cylinder having a tip inner diameter of 0.2 mm, a rear end inner diameter of 3 mm, and a length of 25 mm.

  After filling the hollow cylinder with the sample, steps S1 to S8 in FIG. 1 were executed. In step S <b> 9, the aspirating unit 18 was operated, and the specimen was aspirated from the discharge port at the tip of the hollow cylinder via the cap 17. Then, about 50 μl of the sample was left inside the hollow cylinder.

  Steps S10 to S11 are executed, a dry nitrogen gas introduction system having a pressure of 0.2 MPa is connected to the rear end of the hollow cylinder, a valve provided in the middle of the dry nitrogen gas introduction system is opened, and the sample is introduced from the tip of the hollow cylinder. Was discharged. The specimen discharged from the tip of the hollow cylinder became a flying droplet, landed on the stage surface, and cooled. Thus, a solid sample could be obtained.

  After executing Steps S12 to S18, a cross section of the solid sample was created by FIB-SEM, and the cross section was analyzed. As a result, it was observed that the solid sample was in an amorphous state in which pigment particles having a particle diameter of 30 to 80 nm were uniformly dispersed in the solidified solution.

(Example 3)
The apparatus shown in FIG. 7 was prepared, and the solid sample was produced in the procedure shown in FIG.

  After step S18, a cross section of the solid sample was created by FIB-SEM, and the cross section was analyzed. As a result, it was observed that the solid sample was in an amorphous state in which pigment particles having a particle diameter of 30 to 80 nm were uniformly dispersed in the solidified solution.

It is a schematic block diagram of the preparation apparatus of the solid sample of this invention. It is a flowchart figure which shows one procedure of the preparation method of the solid sample by the preparation apparatus of the solid sample shown in FIG. In the apparatus shown in FIG. 1, it is the schematic which shows one procedure which accommodated the stage in the 3rd chamber. FIG. 2 is a schematic diagram showing one procedure for controlling the temperature of the stage in the apparatus shown in FIG. 1. In the apparatus shown in FIG. 1, it is the schematic which shows one procedure which contacts and solidifies a sample to a stage. In the apparatus shown in FIG. 1, it is the schematic which shows one procedure which transfers the solidified sample to another apparatus. It is a schematic block diagram of the preparation apparatus of the solid sample of another form which concerns on this invention. It is a flowchart figure which shows one procedure of the manufacturing method of the solid sample by the solid sample preparation apparatus of another form which concerns on this invention. FIG. 8 is a schematic diagram showing one procedure for contacting and solidifying a sample on a stage in the solid sample manufacturing apparatus shown in FIG. 7. It is a schematic block diagram of the preparation apparatus of the solid sample which this inventor invented previously.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st chamber 2 2nd chamber 3 3rd chamber 4, 5 Shutter 6 Vacuum pump 11 Dewar bottle 12 Temperature transmission part 13 Cooler 14 Stage 15 Introducing rod 16 Sample supply 17 Cap 18 Suction part 19 Sample receiving part 201 Stage 202a Introduction rod 202b Operation unit 203a First chamber 203b Chamber hatch 203c Purge gas opening / closing valve 203d Purge gas introduction port 203e O-ring 204a Second chamber 204b Purge gas opening / closing valve 204c Purge gas introduction port 204d Chamber hatch 204e Switching valve 204f Leak port 205 Vacuum pump 206 Cooler 207 Specimen feeder 208 Discharge control device

Claims (11)

A solid sample preparation room;
Stage,
A sample supply device including a discharge port for discharging the sample, and supplying the sample to the surface of the stage by a discharge operation;
A cooler for cooling the stage;
Have
In the preparation chamber of the solid sample for supplying the specimen to the cooled surface of the stage and solidifying the specimen in the preparation chamber,
A solid sample comprising: an aspirator that sucks the sample from the discharge port in a state where the discharge port of the sample supply unit is shielded from the atmosphere in the manufacturing chamber during standby of the discharge operation of the sample supply unit Manufacturing equipment. The production chamber has a first chamber to which the suction device is attached, and a second chamber to which the cooler is attached,
The solid sample preparation apparatus according to claim 1, wherein a discharge operation of the specimen supply unit is executed in at least one of the first chamber and the second chamber. The production room has a third chamber for accommodating the stage,
The solid sample preparation apparatus according to claim 2, wherein the inside of the second chamber and the inside of the third chamber are set to the same atmosphere. A sample supply mechanism moving mechanism for moving the sample supply device from the first chamber to the second chamber in order to perform the discharge operation of the sample supply device;
A stage moving mechanism for moving the stage from the second chamber to the third chamber in order to take out the solid sample;
The solid sample preparation apparatus according to claim 1, comprising:   The stage is moved from the second chamber to the first chamber in order to execute the discharge operation of the sample supply device, and the stage is moved from the first chamber to the third chamber in order to take out the solid sample. The solid sample preparation apparatus according to any one of claims 1 to 3, further comprising a stage moving mechanism for moving the solid sample.   The solid sample preparation apparatus according to claim 1, wherein the sample supply device is a liquid ejecting head.   The manufacturing chamber isolates the atmosphere in the first chamber from the atmosphere in the second chamber, and isolates the atmosphere in the second chamber from the atmosphere in the third chamber. The solid sample preparation apparatus according to any one of claims 1 to 6, further comprising a possible shutter. The production room has a third chamber for accommodating the stage,
The solid sample preparation apparatus according to claim 1, wherein the third chamber is configured to be separable from the second chamber. In the method for preparing a solid sample,
Preparing a solid sample manufacturing apparatus according to any one of claims 1 to 8,
An introducing step of introducing a dry gas into the production chamber;
A cooling step for cooling the stage;
Performing a discharge operation of the specimen supply device in the fabrication chamber;
A suction step of sucking the sample from the discharge port in a state in which the discharge port of the sample supply unit is shielded from the atmosphere made of the dry gas in the manufacturing chamber when waiting for the discharge operation of the sample supply unit;
A method for producing a solid sample, comprising: The specimen includes a liquid that exhibits a liquid phase at normal temperature and pressure, and a substance that is different from the liquid and exhibits a solid phase or liquid phase at normal temperature and pressure, and the substance is dispersed in the liquid. Prepared specimens,
The specimen is attached as a droplet to the cooled stage surface,
The method for producing a solid sample according to claim 9, wherein the entire region to be observed is made amorphous. In the sample observation method,
Producing a solid sample using the method for producing a solid sample according to claim 10;
An observation step of observing a cross section of the solid sample while maintaining the amorphous state of the solid sample;
A method for observing a sample, comprising:

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