JP5052563B2 - Micro sample fixing apparatus and micro sample fixing method - Google Patents

Description

  The present invention relates to a minute specimen fixing device and a minute specimen fixing method.

  In the research and development of new functional devices and biomaterials such as cells and blood cells, it is necessary to evaluate and improve the materials, physical properties, structure, composition, etc. of prototype prototype devices. In addition, in the manufacturing process of semiconductor devices and the like, it is extremely important to take measures against defects by analyzing fine foreign material such as particles adhering to the semiconductor devices. An analyzer such as an electron microscope is used for the purpose of performing such evaluation and analysis.

  As a method of fixing foreign matter on the base, a glass pipette filled with a liquid material is brought into contact with the semiconductor wafer to which the foreign matter has adhered, and a gas impact is applied from behind the pipette with nitrogen or the like, and the liquid pushed onto the base A method of fixing a foreign substance with a material is known (for example, see Patent Document 1).

  However, it is difficult to evaluate or analyze the foreign matter in the state of the semiconductor wafer. In view of this, a method of transferring a microscopic specimen from a semiconductor wafer to another base and fixing it has been studied.

JP-A-10-307088 (FIGS. 3A to 3C)

  Usually, a method using micro tweezers called nano tweezers is known for transferring a micro sample to a base or the like. However, when transferring a micro sample to the base using this nano tweezers, the micro sample does not move away from the nano tweezers due to the adsorption force, atomic force, or intermolecular force generated by static electricity between the nano tweezers and the micro sample. There is a problem that it is difficult to move, and a minute specimen is easily lost due to static electricity.

The microdetector fixing device of the present invention includes a base having a hydrophilic surface on at least a part of the surface, and an opening provided on the base and having an opening that exposes at least a part of the hydrophilic surface of the base to the outside. A water film, a dew condensation detection electrode including a pair of electrodes for detecting dew condensation of water droplets provided on the base, and a cooling element for cooling the base are provided.

The method for immobilizing a micro-analyte according to the present invention includes a base having a hydrophilic surface on at least a part of the surface, a water repellent having an opening provided on the base and exposing at least a part of the hydrophilic surface of the base to the outside. A step of preparing a micro-analyte fixing apparatus having a dew condensation detection electrode including a pair of electrodes for detecting dew condensation of water droplets provided on the membrane and the base, and a cooling element for cooling the base; and a cooling element By the process of cooling the base and condensing water droplets on the hydrophilic surface in the opening, contacting the water droplets with the condensed microscopic sample and taking them into the water droplets by meniscus force, and the cohesive force when the water droplets volatilize And a step of fixing the specimen to the upper surface of the base.

  According to the present invention, since the minute specimen is moved onto the base by the meniscus force of the water droplet, when the minute specimen is moved to the base, it is surely overcome the adsorption force, atomic force or intermolecular force due to static electricity. There is an effect that it can be fixed on the base.

1 is an enlarged perspective view showing a first embodiment of a micro sample device of the present invention. FIG. 2 is a plan view of the minute specimen illustrated in FIG. 1 as viewed from above. The top view for demonstrating the state before the dew condensation of the micro sample apparatus shown by FIG. The top view for demonstrating the state which the water droplet condensed on the same part of FIG. It is an expanded sectional view for demonstrating a mode that a test substance is fixed on the hydrophilic surface of a base upper surface, and shows the state before a water droplet condenses. The expanded sectional view of the state which showed the change of the state following FIG. 5, and the water droplet condensed. The expanded sectional view which shows the change of the state following FIG. 6, and shows the state which moved the test substance to the vicinity of the water droplet. The expanded sectional view of the state which shows the change of the state following FIG. 7, and the test substance is taken in in a water droplet by meniscus force. The expanded sectional view of the state which showed the change of the state following FIG. 8, and the specimen was fixed to the base upper surface by the cohesion force after the water droplet volatilized. The condensation detection circuit which detects the condensation of a water droplet is shown. The enlarged plan view which shows Embodiment 2 of this invention.

(Embodiment 1)
Hereinafter, an example of an embodiment of a microscopic sample fixing apparatus according to the present invention will be described with reference to FIGS. 1 and 2.
The micro-specimen fixing device 100 includes a base 10 made of a plate-like member such as frosted glass, a heating / cooling stage 20 disposed in contact with the bottom surface of the base 10, and a water repellent formed on the top surface of the base 10. With membrane 30

  As for the base 10, the whole upper surface 11 has hydrophilicity. Although the surface of the rubbed glass is hydrophilic, a hydrophilic film may be formed on the surface of the plate-like member that does not have hydrophilicity. Various methods for forming a hydrophilic film on a glass surface are known. For example, there is a method for forming a metal oxide particle group such as tin oxide on a glass surface.

In a region of the upper surface 11 of the base 10 having hydrophilicity (region surrounded by a two-dot chain line in FIG. 1), a dew condensation detection unit 50 is formed.
The entire upper surface 11 of the base 10 including the dew condensation detection unit 50 is covered with a water repellent film 30.
The water repellent film 10 has a large number of circular first openings 31 in plan view, and the upper surface 11 corresponding to the first openings 31, that is, the hydrophilic surface is exposed.
Various methods for forming a water-repellent film on a glass surface are known. For example, a method of washing a surface with water, ethanol or the like after being immersed in a treatment liquid containing metal oxide fine particles and a silane compound or the like. There is.

  The dew condensation detection unit 50 includes a dew condensation circuit unit including a dew condensation detection electrode 51 including a pair of electrodes of a comb-shaped one electrode 51a and the other electrode 51b, and includes four terminals 91 to 94. Have. The one electrode 51a and the other electrode 51b are arranged so that the teeth of each comb tooth are alternately positioned between the teeth of the counterpart, as shown in an enlarged view in FIG. They are combined with each other so that part of each tooth overlaps.

The condensation detection electrode 51 is exposed to the outside through a second opening 32 (another opening) that is formed in the water repellent film 30 and is circular in plan view.
The two terminals 91 and 93 of the dew condensation detection unit 50 are connected to the DC power source 60 by lead wires 95 and 96, and the remaining two terminals 92 and 94 are connected to the control unit 70 by lead wires 97 and 98. ing.
The control unit 70 has a drive circuit including a switching element that switches the heating / cooling stage 20 between the heating mode and the cooling mode, and is connected to the heating / cooling stage 20 by leads 21 and 22.

The heating / cooling stage 20 is composed of, for example, a Peltier element or the like, and cools the base 10 due to an endothermic phenomenon that occurs at the N → P junction by passing a current through the PN junction, and occurs at the P → N junction. The base 10 is heated by a heat dissipation phenomenon. Switching between heating and cooling is performed by changing the direction of current by the drive circuit of the control unit 70.
In addition, the control unit 70 is connected to the dew condensation display unit 80 by a connection line 71.
When the dew condensation state is detected, the dew condensation display unit 80 displays that the dew condensation state has been reached by a signal from the control unit 70.

  The dew condensation detection unit 50 has three capacitance detection electrodes 52, 53, and 54 in addition to the dew condensation detection electrode 51 exposed to the outside from the second opening 32. Each of the capacitance detection electrodes 52, 53, and 54 has a pair of electrodes composed of a comb-shaped electrode and the other electrode, similarly to the condensation detection electrode 51. The capacitance detection electrodes 52, 53, and 54 constitute the bridge circuit shown in FIG.

In the micro-specimen fixing device 100, the base 10 is cooled by the heating / cooling stage 20, whereby the upper surface 11 of the base 10 exposed from the first opening 31 and the second opening 32 of the water repellent film 30. Water droplets can be condensed on the surface. Then, it is detected by the dew condensation detection unit 50 that the water droplet has been condensed in the second opening 32, and the minute sample is taken into the first opening 31 by the meniscus force, and then the water droplet is volatilized. The minute specimen taken into the first opening 31 by the cohesive force of the water droplet is fixed on the base 10.
Hereinafter, the configuration and operation of each part of the micro sample fixing device of the present invention and the fixing method using the micro sample fixing device will be described in detail.

5 to 8 are enlarged sectional views taken along the line VV in FIG. 1 for explaining the method for immobilizing a microscopic specimen of the present invention.
FIG. 5 shows a state in which the upper surface 11 that is the hydrophilic surface of the base 10 is exposed to the outside from the first opening 31 of the water repellent film 30.
In the state of FIG. 5, when a current causing an endothermic action is applied to the heating / cooling stage 20 from the control unit 70 to cool the base 10, water vapor in the air is exposed from the first opening 31 of the base 10. The water drops 110 adhere to the upper surface 11 of the base 10 thus formed.
In this case, the water droplet 110 is also formed in the second opening 32 as shown in FIG. 4, but does not occur in the region covered with the water repellent film 30.
The fact that the water droplets 110 are condensed in the second opening 32 of the water repellent film 30 is detected by the condensation detection unit 50 and displayed on the condensation display unit 80, so the operator confirms when condensation has occurred. be able to. The condensation detection operation by the condensation detection unit 50 will be described later.

  When water droplets 110 are condensed in the first opening 31 of the water repellent film 30 (see FIG. 6), a micro sample 112 to be evaluated or analyzed by an evaluation device such as an electron microscope is a micro sample called nano tweezers 115, for example. Grip it with a pair of tweezers and bring it close to the water drop 110 (see FIG. 7).

  The nanotweezers 115 has a pair of arms 116 and 117, and a pair of electrostatic actuators for driving the arms 116 and 117, although not shown. Each electrostatic actuator has a fixed electrode having comb teeth on one surface and a movable electrode having comb teeth on the opposite side of the fixed electrode. Each movable electrode electrode is connected to an arm 116 or 117, and when a voltage is applied between the movable electrode and the fixed electrode, the movable electrode moves due to static electricity to open and close the arms 116 and 117. In this way, the micro sample 112 can be gripped by opening and closing the arms 116 and 117.

Then, when the separation distance between the micro sample 112 and the water droplet 110 approaches to some extent, or when the micro sample 112 slightly contacts the water droplet 110, the water droplet 110 jumps to the micro sample 112 and can be cross-linked as shown in FIG. . That is, meniscus (liquid crosslinking) occurs.
This meniscus force is larger than the adsorptive force due to static electricity acting between the minute specimen 112 and the arms 116 and 117 of the nanotweezers 115, or the atomic force or intermolecular force. For this reason, when the current supply to the actuator of the nanotweezer 115 is cut off and the movable lever 117 is opened, the micro sample 112 is taken into the water droplet 110.

As described above, when the minute specimen 112 is taken into the water droplet 110, a current is passed from the control unit 70 to the heating / cooling stage 20 in the direction opposite to that during cooling, so that the heating / cooling stage 20 generates a heat dissipation action.
The base 10 is heated by the heat radiation action of the heating / cooling stage 20, and the water droplets 110 are volatilized. As the water droplets volatilize, a cohesive force acts between the micro sample 112 and the upper surface 11 of the base 10, and the micro sample 112 is fixed to the upper surface 11 of the base 10.
After this state, the base 10 on which the micro sample 112 is fixed is attached to the stage of an evaluation or analysis apparatus such as an electron microscope, and a desired operation is performed.

As described above, according to the micro sample fixing device of the present invention, since the micro sample 112 is taken in by the meniscus force of the water droplet 110, the electrostatic force between the micro sample 112 and the gripping tool such as the nanotweezers 115, or the like Even if an atomic force or an intermolecular force acts, it can be reliably pulled away from the gripping tool. Further, after taking the micro sample 112 into the water droplet 110, the water droplet 110 is volatilized and the micro sample 112 is fixed to the base 10 by the cohesive force of the water droplet 110, so that the micro sample 112 is fixed without any damage. It is possible.
In addition, since a large number of first openings 31 for taking in the micro sample 112 are formed on the base 10, a large number of micro samples 112 can be fixed on one base 10 for evaluation and analysis. Can be efficiently performed, and the sample can be easily stored.

Next, a circuit operation of the dew condensation detection unit 50 that detects that the water droplet 110 has dewed will be described.
FIG. 10 is a dew condensation detection circuit diagram including the dew condensation detection electrode 51 and the three capacitance detection electrodes 52, 53 and 54 shown in FIG.
In the capacitive bridge circuit of FIG. 10, the capacitance, current, current direction, and DC power supply voltage E are as illustrated. Nodes A, B, C, and D in FIG. 10 are connected to terminals 93, 94, 91, and 92 in FIG.

ＢＤＣＢの閉ループより（式２）が成立する。

ＥＡＤＣＥの閉ループより（式３）が成立する。

In FIG. 10, (Equation 1) is established from the closed loop of ADBA.

(Equation 2) is established from the closed loop of BDCB.

(Equation 3) is established from the closed loop of EADCE.

Further, (Equation 4) is established from the current flowing through point B.
I ₁ = I ₂ + I ₅ ... (Formula 4)
Further, (Equation 5) is established from the current flowing through point D.
I ₄ + I ₅ = I ₃ ... (Formula 5)

The following (Formula 6) is obtained from the above (Formula 1) to (Formula 5).

また、電流計の抵抗をＲとすると(式８)が成立する。
Ｖ₅＝I₅Ｒ ・・・・ （式８） Here, since the time displacement of I ₅ is constant, the integral value of the unit time is (Expression 7).

If the resistance of the ammeter is R, (Equation 8) is established.
V ₅ = I ₅ R (8)

Substituting (Equation 7) and (Equation 8) into (Equation 6) yields (Equation 9).

Therefore, when the following (Equation 10) is satisfied, the right side of (Equation 9) becomes 0, and an equilibrium state is reached in which no current flows between the BDs.
When (Equation 10) is not satisfied, a current flows between the BDs.
C ₁ C ₃ = C ₂ C ₄ ... (Formula 10)

Therefore, the capacitance obtained from the capacitance detection electrodes 52, 53, 54 and the condensation detection electrode 51 in a state where no water droplets are condensed is formed so as to satisfy (Equation 10). For example, as shown in FIG. 3, the capacitance C ₄ obtained from the dew condensation detection electrode 51 in a state where the water droplet 110 does not adhere between the one electrode 51a and the other electrode 51b of the dew condensation detection electrode 51, and the other Capacitances C ₁ , C ₂ , and C ₃ obtained from the three capacitance detection electrodes 52, 53, and 54 satisfy (Equation 10).

For example, the capacity before the water drops 110 shown in FIG. 3 are dewed is affected by the relative dielectric constant of 5.5 to 9.9 of the glass substrate and is about 2PF. Capacitances C ₁ , C ₂ and C ₃ obtained from the three capacitance detection electrodes 52, 53 and 54 are also set to 2PF as described above.
In such a state, since (Equation 10) is satisfied, the current I ₅ does not flow between the DBs, and no current is detected.
Here, when the water droplet 110 adheres on the dew condensation detection electrode 51, as shown in FIG. 4, the water droplet 110 is interposed between the one electrode 51a and the other electrode 51b of the dew condensation detection electrode 51, thereby detecting dew condensation. The capacitance C ₄ in the working electrode 51 increases, and (Equation 10) is not satisfied. The capacitance C ₄ obtained from the dew condensation detection electrode 51 after the dew condensation is, for example, about 25 PF, and greatly changes from about 2 PF before the dew condensation. For this reason, a current I ₅ shown in (Equation 9) flows between the BDs.
The current I ₅ flowing between the BDs is detected, a display control signal is supplied from the control unit 70 to the dew condensation display unit 80, and the dew condensation display unit 80 displays that the water droplet 110 has dewed.

(Embodiment 2)
In the first embodiment, the fixed region for fixing the micro sample 112 and the region where the dew condensation detection unit 50 including the dew condensation detection electrode 51 is formed are formed on the same base 10.
On the other hand, in the second embodiment of the present invention illustrated in FIG. 11, the fixed region for fixing the minute specimen and the region where the dew condensation detection unit including the dew condensation detection electrode is formed are formed on different bases. It is a thing.
Hereinafter, a second embodiment of the minute specimen fixing device of the present invention will be described. However, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the micro sample fixing device 200 of Embodiment 2 shown in FIG. 11, a first water-repellent film 30a having the same plane size as the base 10a is formed on the first base 10a. The upper surface of the first base 10a has hydrophilicity as in the first embodiment. The first water repellent film 30a is formed with a large number of first openings 31 exposing the upper surface 11 which is the hydrophilic surface of the first base 10a.

  The upper surface of the second base 10b is hydrophilic as in the first embodiment, and the dew condensation detector 50 is formed on the hydrophilic upper surface as in the first embodiment. The dew condensation detection unit 50 includes a dew condensation detection electrode 51 and three capacitance detection electrodes 52, 53, and 54. In addition, a second water repellent film 30b having the same plane size as the second base 10b is formed on the second base 10b. The second water repellent film 30b has a second opening 32 that exposes the condensation detection electrode 51 to the outside. The three capacitance detection electrodes 52, 53, 54 are covered with the second water repellent film 30b.

  The first base 10 a and the second base 10 b are supported in close contact with the heating / cooling stage 20. According to such a minute sample fixing device 200, the same operation and effect as in the case of the first embodiment can be achieved.

  In addition, in the second embodiment, the first base 10a in which the region for fixing the microscopic sample is formed and the second base 10b in which the dew condensation detection unit 50 are formed are separated from each other. After the micro sample is fixed to the base 10a, only the first base 10a to which the micro sample is fixed is removed for observation or analysis, and another first base 10a to which the micro sample is not fixed is heated and cooled. It can be mounted on the stage 20 to perform a water droplet dew condensation process to a micro-analyte fixing process, thereby improving work efficiency and reducing the cost of the apparatus.

The above-described embodiment can be modified as follows.
(1) The case where the base 10 is mounted on the heating / cooling stage 20 has been described. However, it is possible to volatilize the water droplets 110 by heating, for example, using heat rays such as infrared rays. In this case, the base 10 and the heating means do not need to be disposed in close contact with each other.
Moreover, when there is time allowance, it is possible to volatilize without using a heating means.

(2) The case where the dew condensation detection unit 50 is provided on the base 10 to detect the occurrence of dew condensation on the water droplets has been described. However, if the occurrence of dew condensation is confirmed visually, the dew condensation detection unit 50 needs to be provided. Disappear.
(3) Even when having a dew condensation detection function, only the dew condensation detection electrode 51 is provided on the base 10 or 10b, and the three capacitance detection electrodes 52, 53, 54 are formed on different members. You may make it do.

(4) Although the nanotweezers are used as a gripping tool for moving the micro sample 112 to the vicinity of the water droplet 110, the micro sample 112 is adsorbed by the gripping tool charged with static electricity and moved to the vicinity of the water droplet. Also good. For example, a glass rod rubbed with cloth or leather is charged to +, and ebonite is charged to-, so that a minute specimen can be adsorbed by this static electricity.

(5) It is not necessary to impart hydrophilicity to the entire upper surface 11 of the bases 10, 10a, and 10b, and only the regions exposed from the first opening 31 and the second opening 32 are hydrophilic. You may do it.
(6) The dew condensation detection electrode 51 and the capacitance detection electrodes 52, 53, 54 may be made hydrophilic.

In addition, the minute specimen fixing device of the present invention can be variously modified and configured within the scope of the invention. In short, a base having a hydrophilic surface on at least a part of the surface, and a base A water-repellent film provided on the base and having an opening that exposes at least a part of the hydrophilic surface of the base to the outside, and a pair of electrodes provided on the base for detecting condensation of water droplets Condensation detection electrode and cooling element for cooling the base

Further, the method for immobilizing a microscopic sample of the present invention includes a base having a hydrophilic surface on at least a part of the surface, an opening provided on the base and exposing at least a part of the hydrophilic surface of the base to the outside. A step of preparing a micro-analyte fixing device having a water repellent film , a dew detection electrode including a pair of electrodes for detecting dew condensation of water droplets and a cooling element for cooling the base, provided on the base; Cooling the base with the cooling element to condense the water droplets on the hydrophilic surface in the opening, contacting the water droplets with the condensed micro-specimen, taking them into the water droplets by meniscus force, and aggregation when the water droplets volatilize Fixing the specimen to the upper surface of the base by force.

  The micro sample immobilization apparatus and the micro sample immobilization method of the present invention include evaluation and analysis of new functional devices such as semiconductor devices, bio-related materials such as cells and blood cells, physical properties, structures or compositions, and the like. The present invention can be applied to the evaluation and analysis of the material and composition of foreign matter adhering to the material.

DESCRIPTION OF SYMBOLS 10 Base 10a 1st base 10b 2nd base 11 Upper surface (hydrophilic surface)
DESCRIPTION OF SYMBOLS 20 Heating / cooling stage 30 Water repellent film 30a 1st water repellent film 30b 2nd water repellent film 31 1st opening part 32 2nd opening part 50 Condensation detection part (condensation detection circuit)
51 Condensation detection electrode 52, 53, 54 Capacitance detection electrode 60 DC power supply 70 Control unit 80 Condensation display unit 100, 200 Micro sample fixing device 110 Water droplet 112 Micro sample 115 Nano tweezers

Claims (10)

A base having a hydrophilic surface on at least a part of the surface;
A water repellent film provided on the base and having an opening that exposes at least part of the hydrophilic surface of the base to the outside;
A dew condensation detection electrode including a pair of electrodes for detecting dew condensation of water droplets provided on the base;
And a cooling element that cools the base. 2. The minute specimen fixing device according to claim 1 , wherein the dew condensation detection electrode is provided in another opening of the water-repellent film provided integrally with the base or on a separate base. 3. A micro-specimen fixing device characterized by comprising: 3. The micro sample fixing device according to claim 1 , wherein a dew condensation detection circuit including the dew condensation detection electrode is provided on the base. 4. The minute specimen fixing device according to claim 3 , wherein the dew condensation detection circuit includes three capacitance detection electrodes covered with the water repellent film in addition to the dew condensation detection electrode provided in the other opening. A micro-analyte fixing device comprising an electrode and a capacitive bridge circuit in which these electrodes are connected. In small sample fixing apparatus according to any one of claims 1 to 4, wherein the cooling element is very small sample fixing apparatus characterized by having a heating function for heating the base. A base having a hydrophilic surface on at least a part of the surface, a water repellent film provided on the base and having an opening that exposes at least a part of the hydrophilic surface of the base to the outside , provided on the base Preparing a micro-analyte fixing device having a condensation detection electrode including a pair of electrodes for detecting condensation of water droplets and a cooling element for cooling the base, and
Cooling the base by the cooling element to condense water droplets on the hydrophilic surface in the opening;
Contacting a minute specimen with the condensed water droplet, and taking it into the water droplet by meniscus force;
And a step of fixing the sample to the upper surface of the base by a cohesive force when the water droplet volatilizes. 7. The method of immobilizing a microscopic sample according to claim 6 , wherein the dew condensation detection electrode is provided integrally with the base or in another opening of the water repellent film provided on a separate base. A method for immobilizing a micro-specimen, wherein 8. The microanalyte fixing method according to claim 6 or 7 , further comprising a step of detecting that water droplets are condensed in the other opening using the dew condensation detection electrode. Fixing method. 9. The method of immobilizing a microscopic sample according to claim 8 , wherein the step of detecting the condensation of water droplets in the other opening includes a condensation detection circuit provided on the base including the condensation detection electrode. A method of immobilizing a micro sample characterized by being used. The method for immobilizing a microscopic sample according to any one of claims 6 to 9 , wherein the cooling element has a heating function of heating the base, and the coagulation force when the water droplets volatilize is used. The method of immobilizing a sample on the upper surface of the base includes a step of heating the base and volatilizing the water droplets.

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