JP2005034129A - Probe substrate for detecting nucleic acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a probe substrate for detecting a nucleic acid, capable of miniaturizing the prove substrate on which the probe consisting of the nucleic acid, and the like, are immobilized, for detecting the nucleic acid and improving the detecting accuracy of amount of the nucleic acid to reduce the measurement error. <P>SOLUTION: This probe substrate for detecting the nucleic acid is equipped with the substrate 1 consisting of ceramics, a first circuit layer 2 formed on a first main surface of the substrate 1, a first insulation layer 3 coating the first main surface for covering the first circuit layer 2, a second circuit layer 4 formed on the upper surface of the first insulation layer 3 and electrically connected with the first circuit layer 2 through a penetrating hole formed on the first insulation layer 3, a second insulation layer 5 for covering the second circuit layer 4, installed with an opening part 5a for exposing the one part of the second circuit layer 4, a probe 6 for detecting the nucleic acid, consisting of the immobilized nucleic acid on the second circuit layer 4 exposed from the opening part 5a, a terminal electrode 2a formed on the second main surface of the substrate 1 and a connecting conductor 1a for electrically connecting the terminal electrode 2a with the first circuit layer 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a nucleic acid detection probe substrate on which a probe made of nucleic acid or the like is immobilized for detecting the presence of a base sequence or a gene.

  In recent years, advances in genetics have made it possible to determine the possibility of disease onset and the degree of disease progression by detecting the presence of specific base sequences or specific genes. Methods for detecting the presence of this specific base sequence or specific gene include a fluorescence detection method, an RI (radioisotope) intensity detection method, a current detection method, and the like.

  The fluorescence detection method and the RI intensity detection method are performed using a chip called a DNA (Deoxyribonucleic Acid: deoxyribonucleic acid) array in which probes made of nucleic acids having different sequences are immobilized on the surface of a substrate such as a slide glass. By reacting a probe made of nucleic acid or the like with a sample gene labeled with a fluorescent dye or RI, a sample gene having a sequence complementary to the base sequence of the probe made of nucleic acid or the like is bound to the probe made of nucleic acid or the like. As a result, when the sample gene has a sequence complementary to a probe made of a nucleic acid or the like on the DNA array, a signal of a label such as a fluorescent dye or RI is obtained at a specific position on the DNA array. Therefore, if the position on the DNA array of probes composed of nucleic acids having different base sequences that have been immobilized is known in advance, the base sequence existing in the gene of the sample can be examined. However, since the chemical reaction system is complicated, it takes a long time to detect a base sequence or a specific gene, the operation is complicated, and the economical burden required for detection of the base sequence or the specific gene is large. there were.

A current detection method has been proposed as a method for solving these problems and exhibiting excellent reproducibility and quantification (see Patent Document 1). In the current detection method, a wiring layer made of gold or the like on a substrate such as glass, an insulating layer covered with a resin such as photoresist on the upper surface of the wiring layer, and an opening that exposes a part of the wiring layer And a nucleic acid detection probe substrate having a probe made of nucleic acid or the like immobilized on the wiring layer of the opening. An aqueous solution containing the nucleic acid of the sample is dropped near the opening where the probe made of nucleic acid or the like is immobilized, and the probe made of nucleic acid or the like and the nucleic acid of the sample are hybridized to form two or three different wiring layers. The amount of nucleic acid or the like in the sample can be detected by measuring a reaction current generated by applying a voltage between the electrodes.
JP-A-10-146183 (page 3-5)

  However, when a plurality of wiring layers are formed to provide a plurality of nucleic acid detection parts adjacent to each other on a substrate such as glass, the reaction current adjacent to the vicinity of the opening where the aqueous solution containing the nucleic acid of the sample is dropped is measured. Since the terminal electrode at the end of the wiring layer to be connected is on the same substrate surface, when the probe substrate for nucleic acid detection is further downsized, it is provided adjacent to the opening for dropping the aqueous solution containing the nucleic acid or the like of the sample There was a problem that the distance from the terminal electrode at the end of the wiring layer for measuring the reaction current of the nucleic acid detection unit was shortened, so that the aqueous solution flowed out of the opening and the terminal electrodes were short-circuited. This makes it difficult to further downsize the probe substrate for nucleic acid detection.

  Therefore, the present invention has been completed in view of the above problems, and its purpose is to reduce the size of the probe substrate for nucleic acid detection, further increase the detection accuracy of the amount of nucleic acid, and suppress measurement errors. An object of the present invention is to provide a probe substrate for nucleic acid detection that can be used.

  The probe substrate for nucleic acid detection of the present invention includes a substrate made of ceramic, a first wiring layer formed on a first main surface of the substrate, and the first main surface covering the first wiring layer. A first insulating layer deposited on the first insulating layer and electrically connected to the first wiring layer through a through-hole formed in the first insulating layer. A second wiring layer; a second insulating layer covering the second wiring layer and having an opening provided so as to expose a part of the second wiring layer; and the exposure exposed from the opening. A probe for nucleic acid detection made of nucleic acid fixed to the second wiring layer, a terminal electrode formed on the second main surface of the substrate, and the terminal electrode and the first wiring layer are electrically connected It has a connecting conductor to be connected.

  In the nucleic acid detection probe substrate of the present invention, preferably, the first insulating layer is made of a resin film having an arithmetic average roughness of the surface of 0.1 μm or less.

  The probe substrate for nucleic acid detection of the present invention has an opening for dropping an aqueous solution containing nucleic acid of a sample and a terminal electrode for measuring a reaction current on the first main surface and the second main surface of the substrate, respectively. Since it is formed, it is possible to prevent the aqueous solution containing the nucleic acid or the like of the sample from flowing out to the terminal electrode and the two adjacent terminal electrodes from being short-circuited, and further the aqueous solution containing the nucleic acid or the like dropped into the opening Therefore, it is not necessary to dispose the opening and the terminal electrode apart from each other so that it is difficult to flow into the terminal electrode, and the probe substrate for nucleic acid detection can be miniaturized.

  Further, since the second wiring layer is provided on the upper surface of the first insulating layer of the first main surface, it is very smooth and uniform on the first surface of the substrate made of ceramics with rough surface roughness. A first insulating layer having a simple surface state can be formed, and a second wiring layer for fixing a probe made of nucleic acid or the like can be formed on the upper surface thereof, and a probe made of nucleic acid or the like can be fixed uniformly. Therefore, it is possible to provide a probe substrate for nucleic acid detection that can increase the detection accuracy of the amount of nucleic acid and suppress measurement errors.

  Preferably, the first insulating layer is made of a resin film having a surface arithmetic average roughness of 0.1 μm or less, and therefore, the first insulating layer is formed by spin coating or the like using a varnish-like resin. In this case, it is possible to reduce the amount of the resin that is scattered outside the substrate and is wasted. Further, since the arithmetic average roughness of the surface is 0.1 μm or less, the unevenness on the surface of the second wiring layer on which the probe made of nucleic acid or the like is formed can be made uniform. As a result, a probe made of nucleic acid or the like can be immobilized uniformly.

  FIG. 1 shows an example of an embodiment of a probe substrate for nucleic acid detection of the present invention, (a) is a top view of the probe substrate for nucleic acid detection, (b) is a cross-sectional view taken along line AA ′ of (a), (C) is a bottom view of the probe substrate for nucleic acid detection. In the figure, reference numeral 1 denotes a substrate made of ceramics, 2 denotes a first wiring layer formed on the first main surface of the substrate 1, and 3 denotes a first main surface covering the first wiring layer 2 and covering the first main surface. The attached first insulating layer 4 is formed on the upper surface of the first insulating layer 3, and is electrically connected to the first wiring layer 2 through a through hole formed in the first insulating layer 3. The second wiring layer 5 is provided on the second insulating layer 5 so that a part of the second wiring layer 4 is exposed. The second insulating layer 5 is formed so as to cover the second wiring layer 4. 6 is a probe made of nucleic acid or the like immobilized on the second wiring layer 4 of the opening 5a, 2a is a terminal electrode formed on the second main surface of the substrate 1, and 1a is a first electrode It is a connection conductor for electrically connecting the wiring layer 2 and the terminal electrode 2a.

  According to the probe substrate for nucleic acid detection of the present invention, the opening 5a for dropping an aqueous solution containing nucleic acid or the like of the sample and the terminal electrode 2a for measuring the reaction current include the first main surface of the substrate 1 and the second main surface. Since it is provided separately from the main surface, both main surfaces of the substrate 1 can be used effectively, and an aqueous solution containing the nucleic acid or the like of the sample flows out to the terminal electrode 2a for nucleic acid detection provided adjacently. Therefore, there is no need to increase the distance between the terminal electrode 2a and the opening 5a, and the substrate 1 can be downsized.

  Further, since ceramics is used as the material of the substrate 1, the connection conductor 1a made of a through conductor such as a via hole that conducts electricity between the first main surface and the second main surface of the substrate 1 can be easily formed. Furthermore, since the substrate 1 made of ceramics has strong chemical resistance against strong acids such as sulfuric acid aqueous solution and hydrochloric acid aqueous solution and strong alkali such as sodium hydroxide aqueous solution, the nucleic acid once detected can be removed and reused repeatedly.

Examples of the material of the substrate 1 of the present invention include alumina (Al ₂ O ₃ ) ceramics, mullite (3Al ₂ O ₃ .2SiO ₂ ) ceramics, cordierite (2MgO.2Al ₂ O ₃ .5SiO ₂ ) ceramics, forsterite ( Ceramics such as 2MgO · SiO ₂ ) ceramics, silicon carbide (SiC) ceramics, and silicon nitride (Si ₃ N ₄ ) ceramics are preferable because they can be formed by simultaneous firing with the connection conductor 1a made of a refractory metal such as tungsten or molybdenum. Further, a ceramic made of glass and alumina capable of forming the connection conductor 1a with a metal containing copper as a low melting point metal may be used. When the co-firing method is not used, a through-hole is formed in the substrate 1 by a method such as carbon dioxide laser, other lasers, punching, sandblasting, etching, etc., and then Ag—Pd paste, Ag epoxy resin paste, Cu paste, Au The connection conductor 1a is formed by filling the paste into the through-holes and firing, or applying and firing these to the inner wall of the through-holes and depositing Cu plating, Ni plating, Ag plating, Au plating or the like thereon. Can be formed.

  The first wiring layer 2 and the terminal electrode 2a deposited on the first and second main surfaces of the substrate 1 are W (tungsten), Mo (molybdenum), Mn (manganese), Cu (copper), Ag. A metal containing at least one of (silver), Ni (nickel), Pt (platinum), Au (gold), etc., is formed by a thick film formation method such as a screen printing method or a vapor deposition method, a sputtering method, a CVD method, a plating method. It is formed by a thin film forming method such as. When the first wiring layer 2 and the terminal electrode 2a are formed by a thick film formation method, the thickness may be about 10 to 50 μm. When the first wiring layer 2 and the terminal electrode 2a are formed by a thin film formation method, And it is sufficient.

  Further, when the first wiring layer 2 and the terminal electrode 2a are formed of a thin film, for example, a three-layer structure of an adhesion metal layer, a diffusion prevention layer, and a main conductor layer, an adhesion metal layer, a diffusion prevention layer, a main conductor layer, and an adhesion metal. It is preferable to have a three-layer structure of a four-layer structure, a close-contact metal layer, a main conductor layer, and a close-contact metal layer, and increase the connection strength between the substrate 1 and the first wiring layer 2 by including the close-contact metal layer. Can do. Further, by placing the diffusion preventing layer between the adhesion metal layer and the main conductor layer, the adhesion metal layer can be prevented from diffusing into the main conductor layer, and the substrate 1 and the first wiring layer 2 The long-term connection can be made highly reliable.

The adhesion metal layer is Ti (titanium), Cr (chromium), Ta (tantalum), Nb (niobium), Ni (nickel) -Cr (chromium) alloy, Ta ₂ N in terms of adhesion to the insulating substrate 1. It is preferable to comprise at least one of (tantalum nitride) and the like. The thickness of the adhesion metal layer is preferably about 0.01 to 0.2 μm. If it is less than 0.01 μm, it is difficult to firmly adhere, and if it exceeds 0.2 μm, peeling tends to occur due to internal stress during film formation.

  The diffusion preventing layer prevents Pt (platinum), Pd (palladium), Rh (rhodium), Ni (nickel), Ni-Cr alloy, Ti-W alloy in order to prevent mutual diffusion between the adhesion metal layer and the main conductor layer. It is good to consist of at least one of these. The thickness of the diffusion preventing layer is preferably about 0.05 to 1 μm. If the thickness is less than 0.05 μm, defects such as pinholes are generated, making it difficult to function as a diffusion preventing layer. If the thickness exceeds 1 μm, peeling is likely to occur due to internal stress during film formation. In the case of using a Ni—Cr alloy for the diffusion preventing layer, the adhesion can be secured, so that the adhesion metal layer can be omitted.

  Further, the main conductor layer is preferably made of at least one of Au, Cu, Ag, Al (aluminum), etc., and its thickness is preferably about 0.1 to 5 μm. If it is less than 0.1 μm, the electric resistance tends to increase. If it exceeds 5 μm, peeling tends to occur due to internal stress during film formation. Further, since Au and Ag are precious metals and expensive, it is preferable to form them as thin as possible.

  Pattern processing in the case of a thin film forming method is performed by a photolithography method, an etching method, a lift-off method, or the like.

  The first insulating layer 3 formed to cover the first wiring layer 2 is an organic material such as polyimide, BCB (benzocyclobutene), epoxy resin, fluorine resin, silicon oxide, aluminum oxide, silicon nitride. Inorganic materials such as aluminum nitride are used. When an organic material is used, the first insulating layer 3 can be formed by applying varnish by spin coating, roll coating, die coating, printing, or the like. On the other hand, when an inorganic material is used, it can be formed by vapor deposition, sputtering, CVD, or the like. In the case of an organic material, polyimide is preferable because it is easy to adjust the viscosity for improving surface flatness, and polyimide is also excellent in chemical resistance. Therefore, it is preferable to use polyimide.

  And the surface of the board | substrate 1 which consists of ceramics has a surface void (dent) peculiar to a sintered compact, Even if the surface of the board | substrate 1 is grind | polished and smoothed, the arithmetic mean roughness (Ra) of the surface is 0.02 micrometer-0.05. It is about μm. Actually, since there are many voids that are smaller than the size of the needle of the contact-type surface roughness meter and deep, the state of the surface of the substrate 1 varies greatly depending on the region of the substrate 1 when viewed microscopically. This is derived from a manufacturing process peculiar to the substrate 1 such as a composition variation of the ceramic green sheet before the substrate 1 is sintered and a temperature distribution variation of the sintering furnace when the substrate 1 is sintered. Due to the surface state of the substrate 1, when a wiring layer made of a thin film such as gold is directly formed on the surface of the substrate 1, the surface of the wiring layer has the same arithmetic average roughness following the surface roughness of the substrate 1. Thus, the surface state of the wiring layer in the opening 5a varies greatly depending on the portion of the substrate 1.

  In the case of a probe substrate for nucleic acid detection of a current detection system that detects the amount of nucleic acid or the like in a sample by detecting a minute reaction current due to the binding of nucleic acid, the amount of immobilized probe 6 made of nucleic acid or the like is less than nucleic acid or the like. It changes very sensitively to the surface state of the second wiring layer 4 to which the probe 6 is fixed. For this reason, in the case of the probe substrate for nucleic acid detection using the substrate 1 made of ceramics, it is very important to make the surface state of the second wiring layer 4 to which the probe 6 made of nucleic acid or the like is fixed uniform, If the surface state is made uniform, the detection accuracy of the probe substrate for nucleic acid detection can be increased as a result, and measurement variations can be suppressed.

  In the probe substrate for nucleic acid detection of the present invention, since the second wiring layer 4 is formed on the upper surface of the first insulating layer 3, the surface roughness derived from the substrate 1 in which the first insulating layer 3 is made of ceramics. Can be made flat and the second wiring layer 4 can be made flat, and the probe 6 made of nucleic acid or the like can be fixed uniformly, so that the detection accuracy of the amount of nucleic acid can be increased and measurement errors can be suppressed. it can.

  In the probe substrate for nucleic acid detection of the present invention, the surface of the first insulating layer 3 is flattened in the case of an organic material by adjusting the viscosity or dividing the coating several times and semi-curing each coating. What is necessary is just to make arithmetic mean roughness of the surface of the 1st insulating layer 3 into 0.1 micrometer or less. The arithmetic average roughness of the first insulating layer 3 is larger than the arithmetic average roughness of the surface of the substrate 1 made of the mirror-polished ceramics, but is smaller than the size of the needle of the surface roughness meter on the surface of the substrate 1. Since there are a large number of deep voids, the surface of the first insulating layer 3 is actually a uniform surface having uniform and minute irregularities on the entire surface. For this reason, it is possible to increase the detection accuracy of the probe substrate for nucleic acid detection and suppress measurement variations.

  If the arithmetic average roughness of the surface of the first insulating layer 3 is too small, the adhesion between the first insulating layer 3 and the second wiring layer 4 formed on the upper surface thereof tends to deteriorate. In this case, after the first insulating layer 3 is flattened, a plasma etching process may be performed to form minute irregularities on the surface, and the surface of the first insulating layer 3 after the plasma etching process is performed. The arithmetic average roughness may be adjusted to about 0.05 to 0.1 μm. When the surface state is adjusted by the plasma etching process as described above, the fragile layer due to adhesion of foreign matters existing on the surface of the first insulating layer 3 can be removed, and the bonding with the second wiring layer 4 can be performed. Since the interface can be roughened, the bonding strength between the first insulating layer 3 and the second wiring layer 4 can be increased.

  The thickness of the first insulating layer 3 is preferably about 1 to 100 μm in the case of an organic material. If the thickness is less than 1 μm, the first wiring layer 2 cannot be completely covered because the thickness as the insulating layer is thin, and the first wiring layer 2 and the second wiring layer 4 may be short-circuited. . On the other hand, if the thickness of the first insulating layer 3 exceeds 100 μm, when the organic material of varnish is formed, the entire nucleic acid detection probe substrate may be warped due to curing shrinkage and cannot be used as the nucleic acid detection probe substrate. In addition, the through hole cannot be formed well in the first insulating layer 3, and the first wiring layer 2 and the second wiring layer 4 are hardly electrically connected through the through hole. The through hole provided in the first insulating layer 3 can be formed by a photolithography method, an etching method, a laser ablation method, or the like.

  The thickness of the first insulating layer 3 is preferably about 0.5 to 10 μm in the case of an inorganic material formed by vapor deposition, sputtering, CVD, plating, or the like. If it is less than 0.5 μm, even a dense inorganic material is not sufficient to ensure insulation, and if it exceeds 10 μm, peeling tends to occur due to internal stress during film formation.

  On the other hand, the arithmetic average roughness of the first insulating layer 3 measured with a contact-type surface roughness meter is preferably 0.01 μm or less, and when this surface roughness is exceeded, the surface roughness of the upper surface of the second wiring layer 4 is increased. Increases along the surface of the lower first insulating layer 3, and it becomes difficult to increase the detection accuracy of the probe substrate for nucleic acid detection and suppress measurement variations.

  Alternatively, the first insulating layer 3 may be made of a resin film having a surface arithmetic average roughness of 0.1 μm or less, which is bonded to the substrate 1 and the first wiring layer 2 via the adhesive layer 3a. . In this case, a resin material such as polyimide, BCB (benzocyclobutene), epoxy resin, fluorine resin, polyphenylene sulfide resin, wholly aromatic polyester resin is used as the material of the first insulating layer 3, and the adhesive layer As the material 3a, a polyamideimide resin, a siloxane-modified polyimide resin, a siloxane-modified polyamideimide resin, or the like is used.

  FIG. 3 shows another example of the embodiment of the probe substrate for nucleic acid detection of the present invention in the case where the first insulating layer 3 is made of a resin film, 3 is a first insulating layer made of a resin film, 3a is The adhesive layer is shown. In addition, the same code | symbol was attached | subjected to the part which shows the other same site | part as FIG.

  The first insulating layer 3 is formed by applying the above resin material to a PET (Polyethylene Terephthalate) film using a doctor blade method or the like so that the thickness after drying is about 10 to 200 μm and then drying the PET film. Using a film that has been peeled off and processed into a film shape, a film-like adhesive layer 3a formed by the same process is overlaid and arranged so as to cover the first wiring layer 2 on the first main surface of the substrate 1. These are bonded by applying pressure while heating them using a heating press. Note that it is more preferable to reduce the pressure inside the hot press apparatus and apply pressure while heating in a vacuum state because the substrate 1 and the first insulating layer 3 can be firmly bonded.

  When producing a resin film to be the first insulating layer 3 using a doctor blade method or the like on a PET film, in order to make the arithmetic average roughness of the surface 0.1 μm or less, Use a PET film produced by a method in which the contact roll surface is a mirror surface, a method in which the temperature of the surrounding atmosphere is gently changed so that the surface of the PET film does not dry rapidly, or a method in which both methods are combined. That's fine.

  The thickness of the first insulating layer 3 is preferably about 10 to 200 μm. If it is less than 10 μm, there is a possibility that it may be accidentally broken when adhering to the substrate 1, which tends to be difficult to handle. There is a tendency that the length becomes longer and the conduction resistance becomes larger. The adhesive layer 3a preferably has a thickness after drying of not less than 5 μm and not more than the thickness of the first insulating layer 3. If the thickness of the adhesive layer 3a after drying is less than 5 μm, sufficient strength as an adhesive tends not to be obtained, and peeling between the substrate 1 and the first insulating layer 3 tends to occur. On the other hand, when the thickness of the first insulating layer 3 is exceeded, the surface of the first insulating layer 3 tends to be wavy due to the influence of curing shrinkage of the adhesive layer 3a.

  When the first insulating layer 3 is made of a resin film, the connection conductor 1a is formed on the inner wall of the through hole formed in the substrate 1, that is, the hollow shape in which the through hole is not completely filled with the connection conductor 1a. Even if the through-hole portions of the first conductor layer 2 and the terminal electrode 2a are also open, the first conductor layer 1a is connected via the connection conductor 1a on the inner wall of the through-hole. It is only necessary that the wiring layer 2 and the terminal electrode 2a are electrically connected. In this case, in order to use the first insulating layer 3 processed into a film shape in advance, the aqueous solution containing nucleic acid or the like is used as the first main layer of the substrate 1 with the film-like first insulating layer 3 serving as a lid for the through hole. This is preferable because it does not flow from the surface side to the second main surface side. When the first wiring layer 2 and the terminal electrode 2a are formed after the through hole is formed in the substrate 1 made of ceramics by a method such as carbon dioxide laser, other lasers, punching, sandblasting, etching, etc., the inner wall portion of the through hole is formed. In addition, the connection conductor 1 a can be formed by wrapping the metal film, and the first wiring layer 2 and the terminal electrode 2 can be electrically connected. In this case, the through hole is a hollow connection conductor 1a that is not completely filled with the connection conductor 1a.

  In addition, by using the first insulating layer 3 as a resin film, the manufacturing cost can be reduced as compared with the case where a varnish-like resin is used. That is, when the first insulating layer 3 is formed by spin coating or the like using a varnish-like resin, the amount of resin scattered out of the substrate 1 by centrifugal force is larger than the amount of resin applied to the substrate 1. As a result, more than twice the amount of resin that actually forms the first insulating layer 3 is required. In the case of using a resin film, since it is cut and used by the amount to be attached to the substrate 1 as the first insulating layer 3, there is no waste, and the manufacturing cost can be suppressed.

  The second wiring layer 4 is preferably formed by the thin film formation method described in the description of the first wiring layer 2 and the uppermost layer is made of Au. This is because the probe 6 made of nucleic acid or the like is adsorbed to the surface of Au via a thiol group on the surface of the second wiring layer 4 exposed from the opening 5a after the second insulating layer 5 is formed. It is because it is fixed to. Further, when the arithmetic average roughness of the surface of the first insulating layer 3 is small and the adhesion between the second wiring layer 4 and the first insulating layer 3 is insufficient, the surface of the first insulating layer 3 is By performing the plasma etching process, the arithmetic surface roughness of the first insulating layer 3 may be partially or entirely increased within a range of 1 μm to improve the adhesion by the anchor effect. In this case, the arithmetic surface roughness of the first insulating layer 3 may be about 0.05 to 0.1 μm, and there are no large voids compared to the surface of the substrate 1 made of ceramics, and a uniform uneven surface can be obtained. Therefore, the arithmetic average roughness of the surface of the second wiring layer 4 formed on the upper surface of the first insulating layer 3 is also uniform, and the probe 6 made of nucleic acid or the like can be fixed uniformly.

  The second insulating layer 5 may be made of the same material as the first insulating layer 3, and it is preferable to use a photoresist. Examples of the photoresist include an exposure photoresist, a far ultraviolet photoresist, an X-ray photoresist, and an electron beam photoresist. The thickness of the second insulating layer 5 is preferably 0.1 μm or more in order to ensure insulation, and is preferably 100 μm or less in order to immobilize the probe 6 made of nucleic acid or the like.

  When the probe 6 made of nucleic acid or the like is immobilized on the upper surface of the second wiring layer 4, the surface of the probe 6 made of nucleic acid or the like is fixed after the surface is washed with sulfuric acid, mixed acid, aqua regia, hydrogen chloride or the like. A thiol group is introduced into the terminal of the second wiring layer 4 or the surface of the second wiring layer 4 so that one end of the probe 6 made of nucleic acid or the like is adsorbed to the surface of the second wiring layer 4 through the thiol group and is firmly fixed. To. The probe 6 made of nucleic acid or the like may be single-stranded DNA as well as single-stranded RNA (Ribonucleic Acid: ribonucleic acid), and the number of bases is not particularly limited, but is about 15 to 3000 bases long It is good to be. Note that the probe 6 made of nucleic acid or the like shown in FIG. 1 is exaggerated in size, and actually is much smaller than the thickness of the second insulating layer 5.

  Examples of nucleic acids detected by forming a pair (hybrid) with a probe 6 made of nucleic acid or the like immobilized on the surface of the second wiring layer 4 include nucleic acids such as various viruses, bacteria, parasites, and fungi, and various diseases. It may be a nucleic acid of a cell having a gene or a gene of a cell of various viruses or various diseases, or a part of those genes.

  Detection of the probe 6 made of a hybridized nucleic acid or the like can be performed by measuring a weak current using a reaction current generated when a voltage is applied to the nucleic acid. Thus, by detecting the amount of the probe 6 made of a nucleic acid paired (hybridized) or the like on the second wiring layer 4, the same base sequence as the nucleic acid present in the sample to be measured is obtained. Nucleic acids can be detected.

  Furthermore, in the probe substrate for nucleic acid detection of the present invention, a structure in which the vicinity of the opening 5a has a mortar shape (a shape spreading outwards upward) as shown in FIG. It is also possible to make it. In order to obtain a mortar-like structure in the vicinity of the opening 5a as shown in FIG. 2, the first wiring layer 2 may be provided as a dummy layer below the raised portion of the second insulating layer 5.

  Further, when the first insulating layer 3 is made of a resin film having an arithmetic average surface roughness of 0.1 μm or less, a mortar-like structure as shown in FIG. 4 can be similarly formed.

  Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.

An example of embodiment of the probe substrate for nucleic acid detection of this invention is shown, (a) is a top view of the probe substrate for nucleic acid detection, (b) is a sectional view taken along line AA ′ in (a), (c) FIG. 3 is a bottom view of a nucleic acid detection probe substrate. The other example of embodiment of the probe substrate for nucleic acid detection of this invention is shown, (a) is a top view of the probe substrate for nucleic acid detection, (b) is sectional drawing in the AA 'line of (a), ( c) is a bottom view of the probe substrate for nucleic acid detection. The other example of embodiment of the probe board | substrate for diffusion detection of this invention is shown, (a) is a top view of the probe board | substrate for nucleic acid detection, (b) is sectional drawing in the AA 'line of (a), ( c) is a bottom view of the probe substrate for nucleic acid detection. The other example of embodiment of the probe board | substrate for diffusion detection of this invention is shown, (a) is a top view of the probe board | substrate for nucleic acid detection, (b) is sectional drawing in the AA 'line of (a), ( c) is a bottom view of the probe substrate for nucleic acid detection.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1: Board | substrate 1a: Connection conductor 2: 1st wiring layer 2a: Terminal electrode 3: 1st insulating layer 4: 2nd wiring layer 5: 2nd insulating layer 5a: Opening 6: Probe which consists of nucleic acids etc.

Claims (2)

A substrate made of ceramic, a first wiring layer formed on the first main surface of the substrate, and a first insulating layer deposited on the first main surface so as to cover the first wiring layer A second wiring layer formed on the upper surface of the first insulating layer and electrically connected to the first wiring layer through a through hole formed in the first insulating layer; And a nucleic acid fixed to the second wiring layer exposed from the opening and a second insulating layer provided with an opening so that a part of the second wiring layer is exposed. A probe for detecting nucleic acid, a terminal electrode formed on the second main surface of the substrate, and a connection conductor for electrically connecting the terminal electrode and the first wiring layer. A probe substrate for nucleic acid detection characterized by the above. The probe substrate for nucleic acid detection according to claim 1, wherein the first insulating layer is made of a resin film having an arithmetic average roughness of a surface of 0.1 µm or less.

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