JP6846309B2 - Solution tank device - Google Patents

Description

The present invention relates to a structure for performing measurement using a thin film device.

The nanopore sequencer is a system that measures the current value of the measurement target that passes through the nanopore embedded in the thin film. For example, when the measurement target is DNA (Deoxyribonic Acid), when the DNA passes through the nanopore, it depends on the difference in the bases (adenine (A), guanine (G), cytosine (C), thymine (T)) that make up the DNA. , There is a difference in the current value (called "blocking current value") that blocks the nanopore. As a result, the nanopore sequencer can specify the base sequence.

Factors that determine the DNA reading accuracy of the nanopore sequencer are, for example, the film thickness of the thin film on which the nanopore is formed and the magnitude of the noise of the current passing through the nanopore. The thinner the thin film, the better. The distance between the four bases arranged in the DNA strand next to each other is approximately 0.34 [nm]. As the film thickness becomes thicker than this interval, more bases enter the nanopore at the same time, so the signal obtained as the blocking current is also a signal derived from multiple bases. Therefore, the accuracy of determining the base sequence is lowered, and the signal analysis is complicated. Also, the smaller the noise current, the better. The noise current is added to the value of the blockade current. A reduction in the blocking current is required to increase the discrimination rate of the four bases.

Non-Patent Document 1 discloses observing a difference in blocking current derived from a base species when DNA passes through a thin film nanopore. In Non-Patent Document 1, nanopores are provided on a thin SiN membrane and an insulating film is applied in order to increase the identification rate of the blocking current. As a result, the device capacitance is reduced and the noise current is reduced.

Venta, K., et al., Differentiation of Short, Single-Stranded DNA Homopolymers in Solid-State Nanopores, ACS Nano 7 (5), p. 4629-4636 (2013).

The thin film for measuring biopolymers is easily affected by the potential difference between the solutions on both sides of the thin film, and has a problem that it is broken by the potential difference. In particular, if the device capacitance is reduced to reduce the noise current, the probability of initial defects occurring in the thin film increases.

From the experiment, it was confirmed that the noise current can be reduced by applying an insulating film to a device having a thin film membrane having a thickness of 12 to 20 [nm] to reduce the device capacitance. On the other hand, it was confirmed that when the chambers on both sides of the thin film of the noise-reduced low-capacity device were filled with the solution, the initial failure of the thin film breaking often occurred. This initial defect is not mentioned in Non-Patent Document 1. Therefore, the mechanism and countermeasures for the initial failure are unknown.

As a result of the examination, this initial failure is caused by the electric charge difference ΔQ of the solution filled on both sides of the thin film, which amplifies the potential difference ΔV (= ΔQ / C) applied to the thin film as the device capacitance C is reduced, resulting in dielectric breakdown of the thin film. Turned out to be caused by. Furthermore, it was found that one of the main causes of this charge difference is static electricity generated on the outside of the solution tank that fills the solution.

Static electricity is generated when a substance and a substance approach each other to a vicinity of several nm or less and are charged by contact friction. When two kinds of substances are charged by contact friction, it is known that the amount of charge differs depending on the substance. The method of using the same material as the substance that can be contact-rubbed or using a substance that is close to the charged train limits the partner substance that can be contact-friction. Therefore, it may be charged due to changes in atmospheric conditions or contact friction with other substances. In addition, measures to adjust the atmospheric conditions, such as raising the humidity to promote discharge or using an ionizer, require maintenance of the atmospheric condition adjusting equipment. In addition, noise due to vibration of the atmosphere condition adjusting device becomes a problem.

The present invention provides a structure that suppresses initial defects of a thin film.

The solution tank device, which is one aspect of the invention disclosed in the present application, is a solution tank device that allows a measurement target to pass from a first region to a second region, and is 1 μm or less that separates the first region from the second region. An insulating thin film having a thickness, a first solution tank that supports one side of both sides of the thin film, a second solution tank that supports the other side of both sides of the thin film, and the above. It is characterized by including a third solution tank provided outside the first and second solution tanks.

According to a typical embodiment of the present invention, the probability of thin film destruction due to a potential difference between solutions can be reduced. Issues, configurations and effects other than those mentioned above will be clarified by the explanation of the following examples.

FIG. 1 is a cross-sectional view of the thin film device. FIG. 2 is a graph showing the relationship between the device capacitance and the noise current. FIG. 3 is a graph showing the relationship between the noise current and the leak current. FIG. 4 is an explanatory diagram showing a mechanism in which an initial defect is created by static electricity generated outside the solution tank. FIG. 5 is an explanatory diagram (A) showing the experimental setup and a graph (B) showing the time change of the potential difference on both sides of the thin film when static electricity is applied. FIG. 6 is a graph showing the relationship between the charge density difference of static electricity and the film thickness of the thin film. FIG. 7 is a graph showing the change in potential difference when static electricity is applied in the solution tank. FIG. 8 is a graph showing the measured values of the surface potential derived from static electricity applied to the solution tank device and the potential difference applied to the thin film device. FIG. 9 is a cross-sectional view of a first example of the solution tank device having the antistatic structure according to the first embodiment. FIG. 10 is a cross-sectional view showing a state in which the solution tank device of the first example having the antistatic structure according to the first embodiment is filled with a solution. FIG. 11 is a cross-sectional view showing a state in which the solution tank device of the first example having the antistatic structure according to the first embodiment is filled with a solution and an electrode having an electric wiring is arranged. FIG. 12 is a diagram showing a procedure for introducing a solution into the solution tank device of the first example having the antistatic structure according to the first embodiment. FIG. 13 is a cross-sectional view of a second example of the solution tank device having the antistatic structure according to the first embodiment. FIG. 14 is a cross-sectional view of a third example of the solution tank device having the antistatic structure according to the first embodiment. FIG. 15 is a diagram showing a procedure for introducing a solution into the solution tank device of the third example having the antistatic structure according to the first embodiment. FIG. 16 is an explanatory diagram showing an example of a nanopore sequencer. FIG. 17 is an explanatory diagram showing an example of the flow of the nanopore sequencer. FIG. 18 is a diagram showing actual measurement values when micropores are formed in a thin film device by an electric method using the solution tank device according to Example 1. FIG. 19 is a cross-sectional view showing an example of the solution tank device according to the second embodiment.

<Embodiment 1>
First, the experimental results show the effect of reducing noise current due to the reduction of device capacitance, the principle of initial failure that occurs when the solution is filled on both sides of the thin film due to the reduction of device capacitance, and the mechanism for preventing this initial failure. The explanation will be based on.

<Thin film device>
FIG. 1 is a cross-sectional view of the thin film device. (A) is a thin film device to which the insulating film 51 is not coated, and (B) is a thin film device to which the insulating film 51 is coated. The thin film device is composed of a thin film 100 and a support substrate 52 that supports the thin film 100. The front surface side (upper side in FIG. 1) and the back surface side (lower side in FIG. 1) of the thin film 100 are filled with the solution 103. The solution 103 and the thin film device are sealed by a solution tank (not shown). The thin film 100 is, for example, a SiN thin film having a thickness of 20 [nm] and an area of 100 [μm ^{2] or less.} The support substrate 52 is, for example, a silicon substrate having a thickness of 725 [μm].

In (A), the first capacitance on the side where the support substrate 52 exists is C1, and the second capacitance on the region where the support substrate 52 does not exist is C2. The combined capacity C of this thin film device is C = C1 + C2. In (B), the insulating film 51 is coated on the front surface of the thin film 100 on the side opposite to the back surface supported by the support substrate 52. Let C1'be the first capacitance on the side where the support substrate 52 exists, and C2 be the second capacitance on the side where the support substrate 52 does not exist. The combined capacity C'is C'= C1'+ C2.

Since the insulating film 51 is applied to the thin film device of (B), the first capacitance C1'of the thin film device of (B) is lower than the first capacitance C1 of the thin film device of (A) (C1> C1). '). Therefore, the combined capacity C'of the thin film device of (B) is smaller than the combined capacity C of the thin film device of (A) (C> C').

FIG. 2 is a graph showing the relationship between the device capacitance and the noise current. The horizontal axis is the device capacitance (combined capacitance of the thin film device), and the vertical axis is the noise current. In FIG. 1B, it was confirmed that the noise current can be reduced by reducing the combined capacitance C'by increasing the coating amount of the insulating film 51. As a result, as in Non-Patent Document 1, the noise current of the thin film device manufactured by us decreased monotonically as the device capacitance decreased. As described above, it was confirmed that the noise was reduced by applying the insulating film 51, but as described above, when the chamber on both sides of the thin film 100 of the low-capacity device with reduced noise was filled with the solution 103, the device capacity was reduced. It was found that an initial failure occurred accordingly.

FIG. 3 is a graph showing the relationship between the noise current and the leak current. The horizontal axis is the noise current, and the vertical axis is the leak current. The graph in FIG. 3 shows the presence or absence of initial failure, and the noise current band is set to 1 [MHz], the applied voltage of the leak current is set to 0.1 [V], and the experimental results comparing the noise current and the leak current are performed. Is.

In this experiment, when the thin film 100 is not broken or has a small defect with a size of about 1 [nm], the current value flowing when a voltage of 0.1 [V] is applied is about ^10-10. [A] It becomes the following. On the other hand, when an initial defect having a size of 1 [nm] or more occurs in the thin film 100, ^{a current of about 10-10} [A] or more flows through the initial defect when a voltage of 0.1 [V] is applied.

As shown in FIG. 3, the smaller the noise current of the solution tank device, the lower the capacity. In conventional solution tank devices containing only insulating materials, the leakage current increases as the noise current decreases. On the other hand, in the solution tank device according to the first embodiment, as will be described later, a third solution tank covers the outside of the first and second solution tanks made of an insulating material. Therefore, the leakage current is greatly reduced compared to the conventional solution tank device, and the occurrence of initial defects is suppressed.

<Initial defect generation mechanism>
FIG. 4 is an explanatory diagram showing a mechanism in which an initial defect is created by static electricity generated outside the solution tank. (A) indicates the initial state, (b) indicates the next state of (a), and (c) indicates the next state of (b). (A) In the initial state, there is no static electricity 10 outside the solution tanks 101 and 102, which are solution tank devices, and there is a difference between the amount of electric charge contained in the solution 103 and the amount of electric charge contained in the solution 104. Make it not exist. If static electricity 10 is generated on the outside of the solution tank 101 in the state of (b), an electric double layer is formed by the static electricity 10 generated on the outside of the solution tank 101 and the electric charge in the solution 103 in the solution tank 101. Assuming that the static electricity 10 generated outside the solution tank 101 has a positive charge, the charge inside the solution 103 constituting the electric double layer is a negative charge, and the charge of the diffusion layer and the bulk solution of the solution 103 is positive. Biased to.

When the amount of static electricity 10 contained in the upper solution tank 101 and the amount of static electricity 10 contained in the lower solution tank 102 are different, the charges Q1 and Q2 of the solution 103 and the solution 104 are different from each other. The charge difference ΔQ = | Q1-Q2 | between the solutions 103 and 104 gives the thin film 100 a potential difference ΔV (= ΔQ / C). In particular, when the capacitance C of the thin film device is small, the potential difference ΔV becomes large, and the thin film 100 is dielectrically broken down to generate holes as in the state of (c).

FIG. 5A is an explanatory diagram showing an experimental setup. The experimental setup is an experimental device for giving a potential difference that causes dielectric breakdown of the thin film 100 due to the generation of static electricity 10. In this experiment, a high-capacity thin film device having a device capacitance of 1000 [pF] was used so that the thin film 100 would not be damaged by the charge difference given by the static electricity 10.

The initial state of this experiment is a state in which the charge difference between the solutions 103 and 104 is eliminated as shown in (A-1), and the solution tank 101 is caused by contact friction with an external object as shown in (A-2). It is assumed that static electricity 10 is applied to the outside of the. The external object is, for example, the installation surface of the solution tank device, the jig that holds the solution tank, or the user's hand.

FIG. 5B is a graph showing the time change of the potential difference on both sides of the thin film 100 when static electricity 10 is applied. The horizontal axis of the graph indicates time, and the vertical axis indicates the potential difference on both sides of the thin film 100. In the graph, the time during which the static electricity 10 is applied is indicated by "*". After applying static electricity 10, the potential difference increases to 2 [V]. This potential difference is considered to become even larger when the device capacitance is reduced. For example, when SiN having a capacity of 100 [pF] and a film thickness of 10 [nm] is used for the thin film, the potential difference becomes 20 [V]. At this time, the electric field applied to the thin film is 2 [V / nm]. Since the electric field is larger than the dielectric breakdown voltage 1 [V / nm] of the SiN thin film, the thin film 100 is broken.

The conditions under which holes are generated in the thin film 100 due to dielectric breakdown vary depending on the device capacitance C of the thin film device, but in addition, the film thickness t [nm] of the thin film 100 and the dielectric breakdown voltage E [V / of the thin film 100]. It also changes depending on [nm], the area S [m2] where static electricity 10 is generated in the solution tanks 101 and 102, and the charge density difference Δσ [C / m ^{2] of static electricity 10.} The charge density difference Δσ [C / m ² ] of the allowable static electricity 10 is expressed by the following equation.

Δσ = (E × t × C) / S ・ ・ ・ ・ ・ (1)

FIG. 6 is a graph showing the relationship between the charge density difference Δσ of the static electricity 10 and the film thickness t of the thin film 100. The horizontal axis represents the film thickness t, and the vertical axis represents the charge density difference Δσ. In FIG. 7, as an example, the dielectric breakdown voltage E is E = 1 [V / nm], the area S where static electricity 10 is generated in the solution tanks 101 and 102 is S = 1 [cm ² ], and the device capacity C is C = 10 [. pF] was assumed.

Since the maximum charge density that can be generated on the insulator surface is ± 5 × 10-5 [C / m ² ], under these conditions, a thin film device with a film thickness of 1 [μm] or less is insulated by static electricity 10. Destruction can occur. In this way, by using the equation (1), it is possible to roughly estimate the charge density difference Δσ of the allowable static electricity 10, and it is possible to determine whether or not countermeasures against static electricity are necessary.

FIG. 7 is a graph showing the change in potential difference when static electricity is applied in the solution tank. The solution tank device having the antistatic mechanism of Example 1 reduces the potential difference generated between the solutions 103 and 104. FIG. 7 shows the time change of the potential difference after applying static electricity 10 to the outside of the solution tank 101 as in FIG. 5B. The potential difference at 0 [s] corresponds to the potential difference immediately after the static electricity 10 is applied. As can be seen from FIG. 7, it was found that the potential difference can be reduced by the solution tank device having the antistatic mechanism of Example 1.

FIG. 8 is a graph showing the relationship between the surface potential derived from static electricity given to the solution tank device under control and the measured value of the potential difference actually applied to the thin film device at that time. Here, Vs is the surface potential derived from static electricity, Ve is the potential difference applied to the thin film device, Cf is the capacitance of the solution tank device, and Cd is the device capacitance of the thin film device. The experiment was conducted under the conditions of Cd of 1000 [pF] and Cf of 3 [pF]. To simplify the equivalent circuit of the electrical circuit of the solution tank device, it can be regarded as a structure in which a voltage is applied to the series circuit of the capacitor as shown in the circuit diagram shown on the right of FIG. At this time, the voltage Ve applied to the thin film device is expressed by the following equation.

Ve = (Cf / (Cf + Cd)) × Vs ... (2)

The theoretical straight line predicted by Eq. (2) and the regression line predicted from the measured values are almost the same, and the surface potential derived from static electricity is actually applied to the thin film device by Eq. (2). It has been found.

<Example of solution tank device with antistatic mechanism>
Subsequently, the solution tank device having the antistatic mechanism used in the examples will be described with reference to FIGS. 9 to 15. In the solution tank device, the insulating thin film 100 is sandwiched between the first solution tank 101 and the second solution tank 102, and the third solution tank 901 is provided outside the first and second solution tanks, and the third solution tank 901 is provided. The structure is characterized in that a gap 902 exists between the first solution tank 101 and the second solution tank 102. The solution tank device reduces static electricity 10 generated by contact friction with an external object due to this characteristic structure.

FIG. 9 is a cross-sectional view of a first example of the solution tank device having the antistatic structure according to the first embodiment. The solution tank device 900 shown in FIG. 9 has a third solution tank 901 outside the first solution tank 101 and the second solution tank 102. A gap 902 is provided between the third solution tank 901, the first solution tank 101, and the second solution tank 102. The void 902 is preferably filled with a solution. The first, second, and third solution tanks are provided with injection ports 105, 106, and 107 for introducing a solution. The solution tanks 101, 102, and 901 are made of an insulating resin, for example, a ^{polymethylmethacrylate resin having a sheet resistance of 10 14} [Ω] or more. The first solution tank 101 and the second solution tank 102 support the thin film device. The thin film device has a thin film 100 and a support substrate 52. The electric field generated by the static electricity 10 generated on the outside of the solution tanks 101 and 102 may cause dielectric breakdown of the thin film 100 through the gas, liquid, and solid in the solution tanks 101 and 102. The solution filled in the void 902 alleviates the static electricity 10 generated on the outside of the first solution tank 101 and the second solution tank 102, and it is possible to prevent dielectric breakdown of the thin film 100. Static electricity is released mainly by two types of electrical paths. The first path is a path in which the electric charge in the electrostatically charged part is released into the atmosphere by an air discharge when it comes into contact with the solution. The second path is a path in which the electric charge at the electrostatically charged portion is released to the GND by a conductive structure or electrical wiring connected to the GND. The charge accumulated by static electricity is relaxed by these two types of electrical paths. The third solution tank may have a conductive structure, and may be, for example, ^{a resin having a sheet resistance of 10 13} [Ω] or less, or typically a metal. The solution may contain a conductive solvent having the ability to dissipate static electricity, and an aqueous solution is typically preferable. Other than water, it may be a polar solvent such as alcohol such as methanol or ethanol. In addition, the solution may contain an electrolyte that enhances conductivity. Further, it may be an ionic liquid having conductivity.

A third solution tank, for example, a solution tank in which a surfactant is coated on an insulating resin surface may be used. As a result, the conductivity can be enhanced by adsorbing water on the surfaces of the solution tanks 101 and 102. Further, the third solution tank may have a structure in which a conductive material is coated or attached to an insulating resin surface. Alternatively, the third solution tank may have a structure in which a metal thin film is formed by vacuum vapor deposition so that the surface of the insulating resin is covered with a metal having high conductivity. As a result, the static electricity 10 can be effectively leaked.

FIG. 10 is a cross-sectional view of the solution tank device of FIG. 9 when the solution is filled in the first, second, and third solution tanks. The first solution 108, the second solution 109, and the third solution 110 are filled in the first, second, and third solution tanks, respectively. At this time, when the third solution comes into contact with the first and second solution tanks, the surface charge carried by the solution tank device is released via the third solution, and the destruction of the thin film due to static electricity can be avoided. At this time, it is preferable that the electrical wiring is provided as described later, but the static electricity can be sufficiently reduced because the static electricity is released to the atmosphere or the like only through the solution. At this time, the first solution and the second solution may be electrically insulated.

It is preferable that electrodes connected by electrical wiring are arranged in each solution tank of the solution tank device shown in FIG. FIG. 11 shows a cross-sectional view of the solution tank device of FIG. 10 having such an electrode. The first electrode 111, the second electrode 112, and the third electrode 113 are arranged for each solution tank and are electrically connected by contacting the first, second, and third solutions, respectively. At this time, it is preferable that the first solution and the third solution are connected so as to be electrically equipotential. With such an arrangement, the generated static electricity is surely released to the outside by the electrical wiring. Since it is typically grounded to GND, static electricity is released to GND.

The first solution and the second solution are electrically connected via a power source 114 that generates a potential difference. As will be described later, it is possible to electrically process holes in the thin film 100 by utilizing the potential difference generated by the power supply 114, and move the measurement target from the first region to the second region for analysis.

FIG. 12 shows a procedure for introducing a solution into the solution tank device shown in FIG. First, the third solution is introduced into the third solution tank through the injection port. Second, the first solution is introduced into the first solution tank. Finally, the second solution is introduced into the second solution tank. By going through such a process, the static electricity charged on the surfaces of the first and second solution tanks can be released, and then the solution can be introduced into the thin film 100, so that the thin film can be reliably prevented from being destroyed. It becomes. At this time, the third solution and the first solution are connected by electrical wiring and the solution is introduced to realize reliable release of static electricity. In the above, the first solution was introduced into the first solution tank as the second procedure for introducing the solution, but after the second solution was first introduced into the second solution tank, the first solution was introduced into the first solution tank. It may be an introduction procedure.

By the above procedure, after introducing the solution while preventing the thin film from breaking down, a potential difference is given to the thin film 100 by the power supply 114, and a potential difference equal to or higher than the dielectric breakdown voltage of the thin film is applied to electrically process minute holes. Is possible. By preventing the thin film from breaking, it becomes possible to process holes with high accuracy and quality.

In the above solution tank device, the third solution tank does not necessarily have to surround the first solution tank and the second solution tank so as to cover all of them, and the third solution in the third solution tank is the first solution tank and the second solution tank. Any structure may be used as long as it is in contact with a part of the solution tank. For example, the solution tank device of FIG. 9 has a structure in which one surface of the first solution tank and the second solution tank is not in contact with the third solution of the third solution tank, but even with such a structure, static electricity is reduced. The effect of is exhibited. Since the static electricity at the place where the third solution comes into contact is released, it is more desirable that the entire surfaces of the first solution tank and the second solution tank are covered from the viewpoint of preventing dielectric breakdown. However, if it is present at the solution inlet, it may be mixed with the first solution or the second solution, and when it comes into contact with the electrodes provided in the first solution tank or the second solution tank, an electrochemical reaction occurs at the contact point. Will progress and will be electrically connected, making it impossible to evaluate the thin film characteristics correctly. Therefore, it is desirable that the third solution does not come into contact with the solution inlet or the electrode. Therefore, considering the feasibility of arranging the device, as shown in FIG. 11, a structure in which the third solution is not in contact with the solution injection port or the electrode is desirable. Further, when static electricity exists on the surface where the third solution tank and the atmosphere come into contact with each other, a potential difference depending on the capacitance of the third solution tank can be applied to the thin film. Therefore, it is desirable that the surface where the third solution tank and the atmosphere come into contact with each other is made of a conductive member having ^{a sheet resistance of 10 13 Ω or less so that static electricity does not accumulate.}

FIG. 13 is a cross-sectional view of a second example of the solution tank device having the antistatic structure according to the first embodiment. In the solution tank device 1300 of the second example shown in FIG. 13, the injection port 107 of the third solution tank of the solution tank device shown in FIG. 9 is sealed, and the third solution is first introduced into the third solution tank and then sealed. Has a structure that is Such a structure can be assembled by a mechanical assembly method using a typical screw or the like, an injection molding method, resin welding, or the like.

FIG. 14 is a cross-sectional view of a third example of the solution tank device having the antistatic structure according to the first embodiment. The solution tank device 1400 of the third example shown in FIG. 14 has a structure characterized in that the first solution tank and the third solution tank are connected by a flow path 115. By connecting the first solution tank and the third solution tank in this way, the procedure for introducing the solution can be reduced once. Further, by passing the solution through the first solution tank while passing through the third solution tank, it is possible to introduce the solution while removing the charge on the surfaces of the first solution tank and the second solution tank.

FIG. 15 shows a procedure for introducing a solution into the solution tank device of FIG. First, the solution is introduced through the inlet of the third solution tank. At this time, since the third solution tank and the first solution tank are connected by the flow path 115, the solution is continuously introduced into the first solution tank via the flow path, and is introduced from the injection port of the first solution tank. The solution is drained. Next, the solution is introduced into the second solution tank. By going through such a process, the static electricity charged on the surfaces of the first and second solution tanks can be released, and then the solution can be introduced into the thin film 100, so that the thin film can be reliably prevented from being destroyed. It becomes. The flow path 115 is preferably connected by connecting the first solution tank and the third solution tank grounded to GND, but is connected by connecting the second solution tank and the third solution tank connected to the power supply. It may be arranged. However, the first solution tank and the second solution tank must not be connected.

Hereinafter, configurations common to the solution tank devices 900 to 1400 of the first to third examples will be described. The thin film device may be configured such that, for example, a silicon support substrate 52 having a thickness of 725 [μm] supports a SiN thin film 100 having ^{a thickness of 1 [μm] and an area of 100 [μm 2] or less.} When the thin film device is used as a device of the nanopore sequencer, SiO2 may be used for the support substrate 52 in which the thin film 100 is coated with an insulating film. By reducing the device capacitance in this way, noise of high-frequency components can be reduced.

Further, as shown in FIG. 2, in order to sufficiently reduce the noise current, it is desirable to form an insulating film on the thin film device so that the device capacitance is 100 [pF] or less. Further, even if the device capacitance is not reduced, the potential difference generated in the thin film 100 is generated when the insulation breakdown voltage of the thin film device is small or when the initial charge difference ΔQ generated between the upper and lower solutions is large. ΔV (= ΔQ / C) may exceed the breakdown voltage and cause an initial defect in the thin film 100. Therefore, even if the device capacity is not reduced, it is effective to prevent static electricity from being generated by the solution tank devices 900 to 1400 of the first to third examples.

When the thin film device is used for the blockade current measurement, it is necessary to select an appropriate thickness of the thin film 100 according to the size of the measurement target. For example, when the measurement target has a size of about 1 [μm], the film thickness of the thin film 100 is preferably about 1 [μm]. On the other hand, when measuring a biological polymer having a width or length of 20 [nm] or less as a measurement target, it is necessary to use a thin film 100 having a film thickness of 20 [nm] or less in order to improve the resolution as a sensor. At this time, as shown in FIG. 6, as the film thickness t becomes thinner, the charge density difference Δσ at which dielectric breakdown occurs also becomes smaller, so that the occurrence rate of initial defects due to static electricity 10 increases. Therefore, in particular, by mounting a thin film device having a thin film 100 having a film thickness of 20 [nm] or less on the solution tank devices 900 to 1400 of the first to third examples, it is possible to effectively suppress the generation of static electricity 10. it can.

Further, the thin film 100 having holes having a diameter of 10 [nm] or less may be used. When the thin film 100 has pores, a biological polymer such as DNA can be passed through the pores to measure the blocking current. Here, when the electrolytic solution is filled on both sides of the thin film 100, even if the thin film 100 has pores, if the pore diameter is small, the solution resistance generated in the pore portion is large, so that the thin film 100 is 0. A potential difference of 01 [V / nm] or more may occur. Even in the thin film 100 having holes already formed in this way, when a high potential difference of 0.01 [V / nm] or more is given for a time of 1 [s] or more, the thin film 100 has a plurality of holes or holes. It is necessary to prevent the static electricity 10 because the defect such as the spread of the static electricity occurs.

Further, the thin film 100 may not include holes. For example, when the procedure of filling the thin film 100 with solutions 103 and 104 and then applying a voltage to the thin film 100 to open holes with a diameter of 10 [nm] or less in the thin film 100 in a controlled manner, the thin film 100 is placed in a solution tank. At the time of incorporation into 101 and 102, no holes have been opened yet. If the pores are not open, the potential difference applied to the thin film 100 tends to be larger, and uncontrollable pores may open on the thin film 100. Therefore, it is effective to prevent the generation of static electricity 10 when the holes are not opened. Further, the material of the thin film 100 may be an inorganic material such as SiN or Graphene so that solid nanopore sequencing can be performed, or an organic material such as bio-nanopore in which protein nanopores are embedded in a lipid bilayer membrane so that bio-nanopore sequencing can be performed. ..

Further, an O-ring may be sandwiched between the thin film 100 and the solution tanks 101 and 102 to prevent liquid leakage. A small solution resistance in the solution tank leads to a reduction in noise current. Therefore, it is desirable that the flow path length of the injection port is 50 [mm] or less, and that the flow path diameter is also 1 [mm] or more in diameter.

FIG. 16 is an explanatory diagram showing an example of a nanopore sequencer. The nanopore sequencer 1600 shown in FIG. 16 is a measurement system connected to the electrodes of the solution tank device 900 of the first example shown in FIG. 11 and measuring the current passing through the thin film 100 by the computer 117. To measure the current, the electrodes are connected to a power supply or ammeter 116. The computer 117 stores the current value measured by the ammeter 116 in an internal storage device.

As an example, the electrode was an electrode Ag / AgCl electrode having a simple structure and easy to handle, and the solution was a 1M KCl aqueous solution. In addition, the solution contains, for example, DNA, protein, and nucleic acid as biological polymers to be measured. Further, the measurement target may be particles made of an inorganic material or an organic material. That is, the measurement target may be a solution containing a substance that passes through the nanopores.

When the measurement target is DNA, the nanopore sequencer 1600 can specify the base sequence constituting the DNA from the magnitude of the blockade current value when the DNA passes through the nanopore. Further, when the measurement target is a measurement target such as a biological polymer other than DNA or particles of an inorganic material, the nanopore sequencer 1500 estimates the size of the measurement target from the magnitude of the blockade current value when these pass through the nanopore. can do. FIG. 17 shows a series of flows up to the measurement of DNA using the nanopore sequencer configuration shown in FIG. After introducing the solution into the solution tank using the procedure shown in FIG. 12, a micropore is machined by applying a breakdown voltage to the thin film device. After that, the DNA is electrophoresed and guided into minute pores by substituting the measurement target, for example, a solution containing DNA, in either the first or second solution tank and applying a potential difference via a thin film device. It becomes possible to measure DNA.

FIG. 18 shows an experimental diagram in which a minute hole is machined by applying a breakdown voltage to a thin film device after introducing a solution using the solution tank device shown in FIG. 11 according to the procedure shown in FIG. Shown. The horizontal axis shows the total cumulative application time of the pulsed voltage applied to the thin film device, and the vertical axis shows the current value flowing through the thin film device after the pulse voltage is applied. By using the solution tank device according to the first embodiment, the thin film can be kept in an insulated state without being destroyed. In this state, by applying a plurality of voltages corresponding to the dielectric breakdown voltage in a pulse shape, micropores can be formed in the thin film device. In this experiment, a pulsed voltage is applied by gradually increasing the pulse time width from 10 [ms] under the conditions of a device capacitance of 100 [pF], a thin film of 5 [nm], and an insulation breakdown voltage of 4 [V]. Then, the current value after applying the pulse was read by applying a voltage of 0.1 [V]. At this time, a 1 MKCl solution is used as the first solution and the second solution. After applying the pulse voltage multiple times, it was confirmed that a current value corresponding to the nanopore diameter of 1.0 [nm] flows. Therefore, it was confirmed that by using this solution tank device, micropores can be machined by an electrical method without destroying the thin film device under the condition that the device capacity is small.

<Embodiment 2>
The second embodiment is a solution tank device in which the solution tank devices 900 to 1400 of the first to third examples shown in the first embodiment are formed in an array in the plane direction of the thin film 100. In the second embodiment, the solution tank device 900 in which the solution tank device 900 of the first example according to the first embodiment is configured in an array will be described, but the second to third examples may be in an array. This will speed up the measurement of the measurement target.

FIG. 19 is a cross-sectional view showing an example of the solution tank device according to the second embodiment. FIG. 19 is a solution tank device 1900 in which the solution tank device 900 of the first example according to the first embodiment is configured in an array. Also in Example 2, the solution tank device 1900 has a third solution tank. In the solution tanks 101 and 102, a partition wall is provided at the boundary of each thin film 100 to suppress the inflow and outflow of the solution. This makes it possible to reduce crosstalk noise between arrays. Further, although the solution tank 101 has a structure in which the arrays are connected to each other, the solution tank 101 may be separated into individual solution tanks by providing a partition wall.

As described above, according to the solution tank device according to this embodiment, the initial failure of the thin film can be suppressed. In addition, by configuring the thin film to pass the biological polymer as a measurement target, a solution tank device that suppresses the initial failure of the thin film can be used for the measurement of the biological polymer. Further, by dividing the thin film into a plurality of regions, the measurement target can be passed in parallel for each region, and the measurement time can be shortened. Further, by setting the thickness of the thin film to 20 nm or less, when measuring a biological polymer having a width or length of 20 [nm] or less as a measurement target, the resolution as a sensor using a solution tank device can be improved. it can.

Further, by using a thin film having a film thickness of 20 [nm] or less, the generation of static electricity can be effectively suppressed. Further, since the thin film has pores having a diameter of 10 nm or less, it is possible to pass a biological polymer such as DNA through the pores and measure the blocking current. Further, the region surrounded by the first solution tank and one surface of the thin film is filled with the first solution, and the second solution is allowed to exist in the region surrounded by the second solution tank and the other surface of the thin film. By including the measurement target in either the first solution or the second solution, a potential difference is given to the first solution and the second solution through the thin film, so that the blocking current of the measurement target passing through the thin film is increased. Can be measured.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. In addition, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

Claims (14)

A solution tank device that allows a measurement target to pass from the first region to the second region.
An insulating thin film having a thickness of 1 μm or less that separates the first region from the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
It is provided with a third solution tank provided outside the first and second solution tanks .
The third solution tank is a solution tank device ^{having a sheet resistance of 10 13} Ω or less. A solution tank device that allows a measurement target to pass from the first region to the second region.
An insulating thin film having a thickness of 1 μm or less that separates the first region from the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
It is provided with a third solution tank provided outside the first and second solution tanks .
The first solution exists in the region surrounded by the first solution tank and the one surface of the thin film, and the second solution exists in the region surrounded by the second solution tank and the other surface of the thin film. A solution tank device characterized in that a solution is present and a third solution is present in a region surrounded by the third solution tank and the first and second solution tanks. The solution tank device according to claim 1 or 2 , wherein the thin film passes a biological polymer as a measurement target. The solution tank device according to claim 3 , wherein the thin film is divided into a plurality of regions. The solution tank device according to claim 1 or 2 , wherein the thickness of the thin film is 20 nm or less. The solution tank device according to claim 1 or 2 , wherein the thin film includes holes having a diameter of 10 nm or less. The solution tank device according to claim 2 , further comprising electrical wiring for equipotentializing either one of the first solution or the second solution with the third solution. The solution according to claim 1 or 2 , wherein either the third solution tank and the first solution tank or the second solution tank is connected by a flow path. Tank device. A method of introducing a solution into the solution tank device without destroying the solution tank device.
The solution tank device is
An insulating thin film having a thickness of 1 μm or less that separates the first region and the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
A third solution tank provided outside the first and second solution tanks, and
With
The third solution tank has a sheet resistance of 10 ¹³ Ω or less and has a conductivity of 10 13 Ω or less.
The method is
The step of introducing the solution into the third solution tank,
A step of introducing a solution into either the first or second solution tank after introducing the solution into the third solution tank.
A step of introducing a solution into the other of the first or second solution tank after introducing the solution into the third solution tank.
A method characterized by having. A method of introducing a solution into the solution tank device without destroying the solution tank device.
The solution tank device is
An insulating thin film having a thickness of 1 μm or less that separates the first region and the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
A third solution tank provided outside the first and second solution tanks, and
With
The first solution exists in the region surrounded by the first solution tank and the one surface of the thin film, and the second solution exists in the region surrounded by the second solution tank and the other surface of the thin film. The solution exists, and the third solution exists in the region surrounded by the third solution tank and the first and second solution tanks.
The method is
The step of introducing the solution into the third solution tank,
A step of introducing a solution into either the first or second solution tank after introducing the solution into the third solution tank.
A step of introducing a solution into the other of the first or second solution tank after introducing the solution into the third solution tank.
A method characterized by having. A method of introducing a solution into the solution tank device without destroying the solution tank device.
The solution tank device is
An insulating thin film having a thickness of 1 μm or less that separates the first region and the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
A third solution tank provided outside the first and second solution tanks, and
With
The third solution tank has a sheet resistance of 10 ¹³ Ω or less and has a conductivity of 10 13 Ω or less.
The third solution tank and either the first solution tank or the second solution tank are connected by a flow path.
The method is
A step of introducing a solution into the third solution tank, which is connected to either the first solution tank or the second solution tank by a flow path.
A step of introducing a solution into the first solution tank or the second solution tank which is not connected to the third solution tank by a flow path after the solution is introduced into the third solution tank.
A method characterized by having. A method of introducing a solution into the solution tank device without destroying the solution tank device.
The solution tank device is
An insulating thin film having a thickness of 1 μm or less that separates the first region and the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
A third solution tank provided outside the first and second solution tanks, and
With
The first solution exists in the region surrounded by the first solution tank and the one surface of the thin film, and the second solution exists in the region surrounded by the second solution tank and the other surface of the thin film. The solution exists, and the third solution exists in the region surrounded by the third solution tank and the first and second solution tanks.
The third solution tank and either the first solution tank or the second solution tank are connected by a flow path.
The method is
A step of introducing a solution into the third solution tank, which is connected to either the first solution tank or the second solution tank by a flow path.
A step of introducing a solution into the first solution tank or the second solution tank which is not connected to the third solution tank by a flow path after the solution is introduced into the third solution tank.
A method characterized by having. A method of introducing a solution into the solution tank device and electrically processing holes without destroying the solution tank device.
The solution tank device is
An insulating thin film having a thickness of 1 μm or less that separates the first region and the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
A third solution tank provided outside the first and second solution tanks, and
With
The third solution tank has a sheet resistance of 10 ¹³ Ω or less and has a conductivity of 10 13 Ω or less.
Electrodes are provided in the first solution and the second solution, respectively.
The method is
The step of introducing the solution into the third solution tank,
A step of introducing a solution into either the first or second solution tank after introducing the solution into the third solution tank.
A step of introducing a solution into the other of the first or second solution tank after introducing the solution into the third solution tank.
A step of forming holes in the thin film by applying a voltage between the electrodes.
A method characterized by having. A method of introducing a solution into the solution tank device and electrically processing holes without destroying the solution tank device.
The solution tank device is
An insulating thin film having a thickness of 1 μm or less that separates the first region and the second region,
A first solution tank that supports one side of both sides of the thin film, and
A second solution tank that supports the other side of both sides of the thin film, and
A third solution tank provided outside the first and second solution tanks, and
With
The first solution exists in the region surrounded by the first solution tank and the one surface of the thin film, and the second solution is present in the region surrounded by the second solution tank and the other surface of the thin film. Is present, and the third solution is present in the region surrounded by the third solution tank and the first and second solution tanks.
Electrodes are provided in the first solution tank and the second solution tank, respectively.
The method is
The step of introducing the solution into the third solution tank,
A step of introducing a solution into either the first or second solution tank after introducing the solution into the third solution tank.
A step of introducing a solution into the other of the first or second solution tank after introducing the solution into the third solution tank.
A step of forming holes in the thin film by applying a voltage between the electrodes.
A method characterized by having.

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