Pore device and particulate measuring system

Abstract

To provide a pore device the reliability of which is high.SOLUTION: A pore device 100 enables a pore chip 102 to be accommodated. A body 120 has its interior divided into a first space 122 and a second space 124 by the pore chip 102, and is constituted to be capable of electrically charging an electrolyte. Electrodes 106, 108 connected to the body 120 and exposed at least in part to the inner space of the body 120 are formed on a substrate 110. Each of the electrodes 106, 108 includes a first metal layer 132 formed on the substrate 110 and a carbon barrier layer 134 formed in a layer upward of the first metal layer 132 in a section of the body 120 exposed to inner spaces 122, 124.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to pore devices. [Background technology]

[0002] A particle size distribution measurement method called the electrical sensing zone method (Coulter principle) is known. In this measurement method, an electrolyte containing particles is passed through a small hole called a nanopore. When a particle passes through the pore, the electrolyte in the pore decreases by an amount equivalent to the particle's volume, increasing the electrical resistance of the pore. Therefore, by measuring the electrical resistance of the pore, the particle volume (i.e., particle size) can be measured.

[0003] 1 is a block diagram of a particle measurement system 1R using an electrical sensing zone method. The particle measurement system 1R includes a pore device 100R, a measuring apparatus 200R, and a data processing apparatus 300.

[0004] The interior of the pore device 100R is filled with an electrolyte 2 containing particles 4 to be detected. The interior of the pore device 100R is separated into two spaces by a pore chip 102, and electrodes 106 and 108 are provided in the two spaces. When a potential difference is generated between the electrodes 106 and 108, an ionic current flows between the electrodes, and the particles 4 move from one space to the other through the pores 104 by electrophoresis.

[0005] The measurement device 200R generates a potential difference between the electrode pair 106, 108 and acquires information correlated with the resistance value Rp between the electrode pair. The measurement device 200R includes a transimpedance amplifier 210, a voltage source 220, and a digitizer 230. The voltage source 220 generates a potential difference Vb between the electrode pair 106, 108. This potential difference Vb serves as a driving source for electrophoresis and also as a bias signal for measuring the resistance value Rp.

[0006] A minute current Is that is inversely proportional to the resistance of the pore 104 flows between the pair of electrodes 106 and 108 . Is=Vb / Rp …(1)

[0007] The transimpedance amplifier 210 converts the minute current Is into a voltage signal Vs. When the conversion gain is r, the following equation holds: Vs = -r × Is … (2) Substituting equation (1) into equation (2) gives equation (3). Vs = -Vb × r / Rp … (3) The digitizer 230 converts the voltage signal Vs into digital data Ds. In this manner, the voltage signal Vs that is inversely proportional to the resistance value Rp of the pore 104 can be obtained by the measurement device 200R.

[0008] 2 is a waveform diagram of an exemplary minute current Is measured by the measurement device 200R. Note that the vertical and horizontal axes of the waveform diagrams and time charts referred to in this specification are appropriately enlarged or reduced for ease of understanding, and each waveform shown is simplified, exaggerated, or emphasized for ease of understanding.

[0009] During the short period that a particle passes through, the resistance value Rp of the pore 104 increases. Therefore, the current Is decreases in a pulsed manner each time a particle passes through. The amplitude of each pulse current correlates with the particle size. The data processing device 300 processes the digital data Ds and analyzes the number and particle size distribution of the particles 4 contained in the electrolyte 2. Part of the data processing device 300 may be a server or a cloud. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2023-2249 [Patent Document 2] International Publication No. WO2021-152954A1 [Patent Document 3] US Patent Application Publication No. 2015 / 0160160 Summary of the Invention [Problem to be solved by the invention]

[0011] 3 is a cross-sectional view of a pore device 100R investigated by the present inventors. The pore device 100R includes a substrate 110 and a body 120. The body 120 includes two spaces 122 and 124 defined by a pore tip 102. The spaces 122 and 124 are filled with an electrolyte solution 2 containing particles 4 during measurement.

[0012] The body 120 is provided on a substrate 110. Wirings 112P and 112N corresponding to the electrodes 106 and 108 are formed on the substrate 110. The wirings 112P and 112N are drawn out from inside the spaces 122 and 124 of the body 120 to the outside, respectively, and perform ion exchange with the electrolyte 2 in an ion exchange region 118 inside the body 120, and are electrically connectable to the measuring device 200 in a contact region 116 outside.

[0013] As a result of examining the pore device 100R of FIG. 3, the present inventors have come to recognize the following problem.

[0014] As the substrate 110, film substrates such as PET (polyethylene terephthalate), printed circuit boards, and glass substrates are possible candidates.

[0015] PET substrates are inexpensive and easy to process, so they are often used in disposable pore devices 100R. Because PET substrates have low heat resistance, the wiring 112P and 112N are often made of silver particles that can be formed at low temperatures.

[0016] However, silver oxidizes quickly, forming a silver oxide insulating film on its surface. This insulating film prevents electrical connection to the substrate 110 in the contact area 116. When establishing an electrical connection using a pogo pin or similar, wiping can break through the silver oxide insulating film to expose the new surface and establish contact, but the thinness of the silver wiring makes the contact unstable.

[0017] Printed circuit boards are generally used for electrode formation and are made of glass epoxy materials such as FR-4 (Flame Retardant Type 4). In the case of printed circuit boards, the wiring layer is copper, which is usually gold-plated on top, so there is no need to worry about oxidation like with PET, and contact with external electrodes is also good.

[0018] However, when used as the substrate 110 of the pore device 100R, when the inside of the body 120 is filled with the electrolyte 2, chloride ions contained in the electrolyte 2 pass through the silver-silver chloride electrode and the gold plating underneath and reach the copper of the wiring layer, causing copper chlorination, and copper chloride, an insulator, precipitates on the surface of the electrode, resulting in poor contact.

[0019] Glass substrates are often used in electrochemical measurements that use electrolytes. Because glass has a high melting point, gold can be directly wired using vapor deposition. This means there is less risk of chloride buildup, as with printed circuit boards, and less risk of poor contact, as with PET substrates. However, the price is more than one order of magnitude higher, making it unsuitable for disposable pore devices.

[0020] The present disclosure has been made in this context, and one exemplary purpose of an embodiment thereof is to provide a highly reliable pore device. [Means for solving the problem]

[0021] One aspect of the present disclosure relates to a pore device. The pore device includes a body having an internal space including a first space and a second space communicating with each other via pores, configured to be fillable with an electrolyte, and a substrate connected to the body and having electrodes formed thereon, at least a portion of which is exposed to the internal space of the body. Each electrode includes a first metal layer formed on the substrate and a carbon barrier layer formed above the first metal layer in the portion exposed to the internal space of the body.

[0022] Any combination of the above elements, or mutual substitution of elements or expressions between methods, devices, systems, etc., are also valid aspects of the present invention or the present disclosure. Furthermore, the description in this section (Means for Solving the Problems) does not explain all essential features of the present invention, and therefore, subcombinations of the described features may also constitute the present invention. [Effects of the Invention]

[0023] Certain aspects of the present disclosure can improve reliability. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a block diagram of a particle measurement system using an electrical sensing zone method. [Figure 2] FIG. 10 is a waveform diagram of an exemplary minute current Is measured by a measuring device. [Figure 3] FIG. 1 is a cross-sectional view of a pore device investigated by the present inventors. [Figure 4] FIG. 1 is a cross-sectional view of a pore device according to a first embodiment. [Figure 5] FIG. 10 is a diagram showing the results of a surface component analysis of the electrode portion of a comparative sample in which the carbon barrier layer is omitted. [Figure 6] FIG. 10 shows the results of a surface component analysis of the electrode portion of a sample provided with a carbon barrier layer. [Figure 7] FIG. 10 is a cross-sectional view of a pore device according to a second embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a pore device according to Modification 1. [Figure 9] FIG. 10 is a cross-sectional view of a pore device according to Modification 2. DETAILED DESCRIPTION OF THE INVENTION

[0025] (Outline of the embodiment) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0026] A pore device according to one embodiment includes a body having an internal space including a first space and a second space communicating with each other via pores and configured to be fillable with an electrolyte, and a substrate connected to the body and having electrodes formed thereon, at least a portion of which is exposed to the internal space of the body. Each electrode includes a first metal layer formed on the substrate and a carbon barrier layer formed above the first metal layer in the portion exposed to the internal space of the body.

[0027] According to this configuration, the carbon barrier layer can block chloride ions contained in the electrolyte, thereby preventing the chloride ions from reaching the first wiring layer and improving reliability.

[0028] In one embodiment, the substrate is a printed circuit board, the first metal layer is made of Cu, and the electrode may further include a second metal layer made of Ni formed on the first metal layer and a third metal layer made of Au formed on the second metal layer. A carbon barrier layer may be formed on the third metal layer, which can prevent deterioration of the Cu.

[0029] In one embodiment, the substrate is a film substrate, and the material of the first metal layer may be Ag (silver), which can prevent Ag from being chlorinated.

[0030] In one embodiment, the carbon barrier layer may also be formed on the portion of the body exposed to the external space, thereby preventing oxidation of Ag.

[0031] In one embodiment, the electrode may further include an Ag / AgCl (silver-silver chloride) layer formed on the carbon barrier layer, which allows for efficient ion exchange with the electrolyte.

[0032] A particle measurement system according to one embodiment may include any of the pore devices described above and a measuring device that applies an electrical signal to an electrode of the pore device and measures the electrical signal generated in the pore device.

[0033] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, the embodiments are examples and do not limit the disclosure and invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the disclosure and invention.

[0034] In addition, the dimensions (thickness, length, width, etc.) of each component shown in the drawings may be enlarged or reduced as appropriate for ease of understanding. Furthermore, the dimensions of multiple components do not necessarily represent their relative sizes, and even if a component A is depicted as being thicker than another component B in the drawings, it is possible that component A is thinner than component B.

[0035] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected to each other, but also a case in which component A and component B are indirectly connected to each other via other components that do not substantially affect the electrical connection between them or that do not impair the function or effect achieved by their connection.

[0036] Similarly, "a state in which component C is connected (provided) between component A and component B" includes not only a case in which component A and component C, or component B and component C, are directly connected, but also a case in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or that do not impair the function or effect achieved by their combination.

[0037] In addition, in this specification, symbols attached to electrical signals such as voltage signals and current signals, or circuit elements such as resistors, capacitors, and inductors, represent the respective voltage values, current values, or circuit constants (resistance values, capacitance values, inductances) as necessary.

[0038] 4 is a cross-sectional view of the pore device 100A according to embodiment 1. The pore device 100A includes a printed circuit board 110A and a body 120.

[0039] The body 120 has an internal space including a first space (also referred to as a first flow path) 122 and a second space (124) that communicate with each other via a pore. The body 120 is configured so that the internal space can be filled with an electrolyte. In the first embodiment, the body 120 includes a pore chip 102 having a pore formed therein and a pore chip case that houses the pore chip 102, and the internal space of the body 120 is divided into the first space 122 and the second space 124 by the pore chip 102.

[0040] The printed circuit board 110A is a glass epoxy board such as FR4. The printed circuit board 110A is connected to the body 120. On the surface layer of the printed circuit board 110A, a first electrode 106 is formed, at least a portion of which is exposed to a first space 122, which is the internal space of the body 120, and a second electrode 108 is formed, at least a portion of which is exposed to a second space 124, which is the internal space of the body 120.

[0041] The first electrode 106 and the second electrode 108 are wirings 130A having the same wiring structure.

[0042] The wiring 130A includes a first wiring layer 132, a second wiring layer 136, a third wiring layer 138, a carbon barrier layer 134, and an Ag / AgCl layer 140, which are stacked in this order on the printed circuit board 110A. The first wiring layer 132 is made of Cu, the second wiring layer 136 is made of Ni, and the third wiring layer 138 is made of Au. The carbon barrier layer 134 is conductive and is formed on the third wiring layer 138. In a portion (ion exchange region) on the carbon barrier layer 134 that is exposed to the inside of the body 120, an Ag / AgCl layer 140 is formed to efficiently perform ion exchange with the electrolyte solution 2.

[0043] The thickness of the carbon barrier layer 134 is preferably, for example, about 10 μm to 30 μm, specifically about 20 μm. By setting the thickness in this range, chloride ions can be blocked while suppressing increases in manufacturing costs.

[0044] The above is the structure of the pore device 100A. Next, its advantages will be explained. To verify the advantages of the carbon barrier layer 134 in the pore device 100A, a device sample having a carbon barrier layer as shown in FIG. 4 and a comparative device sample omitting the carbon barrier layer were fabricated. Then, the interiors of the two samples were filled with an electrolyte, and a current was applied, after which the surface components of the electrodes were analyzed.

[0045] Figure 5 shows the results of a surface component analysis of the electrode portion of a comparative sample that did not include a carbon barrier layer. It can be seen that in the sample that did not include a carbon barrier layer, large amounts of Cu and Cl were detected on the electrode surface.

[0046] 6 shows the results of a surface component analysis of the electrode portion of the sample with a carbon barrier layer. It can be seen that in the sample with the carbon barrier layer, Cu does not appear on the surface, but a large amount of Ag contained in the Ag / AgCl layer 140 is detected.

[0047] 4 can prevent chloride ions contained in the electrolyte 2 from reaching the first wiring layer 132. This can prevent copper chloride from being generated in the first wiring layer 132 and from being deposited on the electrode surface.

[0048] 7 is a cross-sectional view of a pore device 100B according to embodiment 2. The pore device 100B according to embodiment 2 includes a film substrate 110B instead of the printed circuit board 110A. The film substrate 110B is, for example, a PET substrate, and electrodes 106 and 108 are formed on the film substrate 110B. The electrodes 106 and 108 are formed of wiring 130B having the same structure. The material of the film substrate 110B is not limited to PET, and it can be made from polyimide, cycloolefin polymer, acrylic, etc.

[0049] The wiring 130B includes a stacked first wiring layer 132, a carbon barrier layer 134, and an Ag / AgCl layer 140. The first wiring layer 132 is made of Ag. The carbon barrier layer 134 is formed on the first wiring layer 132. The carbon barrier layer 134 is formed both inside and outside the body 120.

[0050] The above is the configuration of the pore device 100 B. In the pore device 100 B, the carbon barrier layer 134 can prevent chloride ions in the electrolyte 2 from reaching the first wiring layer 132 inside the body 120 .

[0051] Furthermore, on the outside of the body 120, the carbon barrier layer 134 can prevent the first wiring layer 132 from being oxidized.

[0052] Next, a modified example of the wiring 130 will be described.

[0053] (Variation 1) 8 is a cross-sectional view of a pore device 100C according to Modification 1. In Embodiments 1 and 2, the contact region is formed on the upper surface of the substrate 110, but this is not limited thereto. In Modification 1, the contact region 116 is formed on the back surface of the substrate 110, i.e., on the side opposite the ion exchange region 118.

[0054] The wiring 130C has wiring or pads including a first wiring layer 132, a carbon barrier layer 134, and a third wiring layer 138 laminated on the back surface of the substrate 110. The first wiring layer 132 on the upper surface side of the printed circuit board 110A and the first wiring layer 132 on the lower surface side are connected by a via hole 133.

[0055] (Variation 2) 9 is a cross-sectional view of a pore device 100D according to Modification 2. In Modification 2, the contact region 116 and the ion exchange region 118 are connected via wiring 131 and a via hole 133 inside the printed circuit board 110D.

[0056] (Variation 3) In the embodiment, the body is composed of a combination of a pore tip and a pore tip case, but the present disclosure is not limited to this, and the first space and the second space, and the pore connecting them, may be integrally formed in the body.

[0057] The present invention has been described based on the embodiments, but the embodiments merely illustrate the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments as long as they do not deviate from the concept of the present invention defined in the claims. [Explanation of symbols]

[0058] 1. Particle measurement system 2 Electrolyte 4 particles 200 Measuring Equipment 210 Transimpedance Amplifier 220 Voltage Source 230 digitizer 100 pore device 102 Pore Tip 104 pores 106,108 electrode 110 Substrate 110A Printed Circuit Board 110B film substrate 112P, 112N wiring 116 Contact Area 118 Ion Exchange Region 120 Body 122 1st space 124 2nd space 130 Wiring 132 1st wiring layer 134 Carbon Barrier Layer 136 2nd wiring layer 138 3rd wiring layer 140 Ag / AgCl layer

Claims

1. a body having an internal space including a first space and a second space that are in communication with each other via a pore, the body being configured to be able to be filled with an electrolyte; a substrate on which an electrode is formed, the electrode being connected to the body and at least a portion of which is exposed to the interior space of the body; Equipped with Each of the electrodes is a first metal layer formed on the substrate; a carbon barrier layer formed above the first metal layer in a portion of the body exposed to the internal space; A pore device comprising:

2. the substrate is a printed circuit board, the material of the first metal layer is Cu; The electrode is a second metal layer of Ni formed on the first metal layer; a third metal layer of Au formed on the second metal layer; further comprising The pore device of claim 1 , wherein the carbon barrier layer is formed on the third metal layer.

3. the substrate is a film substrate, The pore device according to claim 1, wherein the material of the first metal layer is Ag.

4. The pore device according to claim 3 , wherein the carbon barrier layer is also formed on a portion of the body exposed to the external space.

5. A pore device according to any one of claims 1 to 4, characterized in that the thickness of the carbon barrier layer is 10 μm to 30 μm.

6. The pore device according to any one of claims 1 to 4, wherein the electrode further comprises an Ag / AgCl layer formed on the carbon barrier layer.

7. A pore device according to any one of claims 1 to 4; A measuring device that applies an electrical signal to the electrode of the pore device and measures the electrical signal generated in the pore device; A particle measurement system comprising:

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