JP2006084316A - Mounting structure of piezoelectric vibrator for qcm sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure of a piezoelectric vibrator for a QCM (Quartz Crystal Microbalance) sensor that prevents invasion of sample liquid to a clearance between a piezoelectric vibrator and a substrate, does not require sealing of an outer periphery of a piezoelectric vibrator with an adhesive, and has a stable performance because stress to the piezoelectric vibrator by sealing of the outer periphery of the piezoelectric vibrator does not occur. <P>SOLUTION: In the mounting structure of the piezoelectric vibrator for the QCM sensor where a metal pattern for excitation formed on the piezoelectric vibrator on a substantially flat plate is connected to a metal wire disposed on the substrate, a water repellent film is disposed on the surface of the substrate on the mounted side of at least the piezoelectric vibrator. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention detects the component of the sample adsorbed on the surface of the metal pattern from the change in the electrical characteristics such as the oscillation frequency and impedance of the piezoelectric vibrator when the metal pattern on the piezoelectric vibrator is exposed to the sample gas or sample solution. The present invention relates to a mounting structure of a piezoelectric vibrator for a QCM (Quartz Crystal Microbalance) sensor to be quantified.

  In recent years, a QCM sensor as a chemical biosensor that applies a microbalance principle using a piezoelectric vibrator has attracted attention. The structure of a conventional QCM sensor will be described with reference to FIG. In FIG. 15, one surface of the piezoelectric vibrator 1 is flat, and one excitation electrode pattern 2a is formed on this surface. A plurality of depressions are formed on the other surface of the piezoelectric vibrator 1 by a process such as etching, and the other excitation electrode pattern 2b is formed in the depressions. On this electrode pattern 2b, a receptor 10 that selectively adsorbs the substance to be measured is provided, and a tetrafluoroethylene pattern 11 having an opening is formed so that only the electrode pattern 2b portion is exposed. It has a structure.

Since the above QCM sensor allows the sample liquid to be placed only on the electrode pattern 2b due to the hydrophobic nature of the tetrafluoroethylene pattern 11 when the sample liquid is dropped into the opening of the tetrafluoroethylene pattern 11, It is possible to prevent the sample from protruding from the receptor 10.
JP 2003-222580 A (page 5, FIG. 1)

  However, the above-described QCM sensor piezoelectric vibrator has the following problems.

  In the structure of the conventional QCM sensor shown in Patent Document 1, since it is necessary to dip a depression on one surface of the vibrator, the processes such as photolithography and etching are performed as compared with the case where a vibrator on a flat plate is used. Was troublesome. Further, in the configuration of Patent Document 1, since the amount of sample accepted by the receptor 10 is small, when the target substance contained in the sample is extremely small, the amount adsorbed on one receptor 10 is also small. The detection accuracy was limited.

  When the target substance contained in the document is extremely small, it is possible to prepare a large number of samples, put the samples in a beaker or the like, and place the vibrator directly into the sample of the beaker. Since the electrode pattern is exposed on both sides, it is necessary to electrically insulate, but no specific countermeasure has been proposed.

  The present invention provides a mounting structure for a QCM sensor piezoelectric vibrator that solves the above-described problems, has good characteristics as a QCM sensor, is excellent in productivity, and can be used even when the number of samples is small or large. The purpose is that.

  In order to achieve the above object, the structure described below is adopted for the mounting structure of the piezoelectric vibrator in the present invention.

The mounting structure of the piezoelectric vibrator for QCM sensors of the present invention is a mounting structure of a piezoelectric vibrator for QCM sensors in which a metal pattern for excitation provided on a substantially flat piezoelectric vibrator is connected to a metal wiring provided on a substrate. A water repellent film is provided on at least the surface of the substrate on the side where the piezoelectric vibrator is mounted.

  Further, the water repellent film is provided on substantially the entire surface of the substrate.

  Further, in the QCM sensor piezoelectric vibrator mounting structure of the present invention, the water repellent film has an opening in a portion facing the metal pattern of the piezoelectric vibrator, and the substrate surface exposed to the opening is provided with the opening. A metal wiring is provided.

  In the QCM sensor piezoelectric vibrator mounting structure of the present invention, a gap between the outer periphery of the piezoelectric vibrator and the substrate is sealed with a sealing material, and the water repellent film is also formed on the surface of the sealing material. Is provided.

  The water repellent film is also provided on the exposed surface of the piezoelectric vibrator, avoiding the excitation metal pattern.

  Also, the QCM sensor piezoelectric vibrator mounting structure according to the present invention is characterized in that the piezoelectric vibrator is mounted on the substrate while maintaining a gap, and the gap communicates with the outside.

  The piezoelectric vibrator is characterized in that only the metal pattern portion is fixed to the substrate.

  The QCM sensor piezoelectric vibrator mounting structure of the present invention is characterized in that the piezoelectric vibrator is a crystal.

  According to the present invention, the water repellent film is provided on the surface of the substrate on which the QCM sensor piezoelectric vibrator is mounted. Therefore, when the amount of the sample liquid is small, an appropriate amount of the sample liquid is supplied onto the piezoelectric vibrator. Can be analyzed. When the sample liquid is contained in a container such as a beaker, the substrate on which the piezoelectric vibrator is mounted can be immersed in the container. In this case, since the substrate surface is covered with the water-repellent film, the component to be analyzed can be prevented from adsorbing to the substrate surface.

  Further, according to the present invention, the piezoelectric vibrator may be mounted while maintaining a gap with the substrate so that the gap communicates with the outside. In this case, since only the metal pattern portion of the piezoelectric vibrator is fixed to the substrate and no sealing material is provided around the piezoelectric vibrator, useless stress is not generated in the piezoelectric vibrator, and stable vibration characteristics can be obtained.

  Hereinafter, a mounting structure of a piezoelectric vibrator for a QCM sensor according to an optimal embodiment of the present invention will be described with reference to the drawings. 1 to 8 show a QCM sensor piezoelectric vibrator and its mounting structure in the first embodiment. As shown in FIG. 1, excitation electrode patterns 2a and 2b are provided on both surfaces of the piezoelectric vibrator 1, respectively. And each edge part of this electrode pattern 2a, 2b is connected to the metal wiring 4a, 4b provided in the board | substrate 3. FIG. Further, the piezoelectric vibrator for QCM sensor has a mounting structure in which the space between the outer peripheral portion 1 a of the piezoelectric vibrator 1 and the substrate 3 is sealed with a sealing material 7. Further, the surface of the piezoelectric vibrator 1, the sealing material 7 and the substrate 3 other than the excitation portion of the electrode pattern 2a has a structure in which a water repellent film 5 is formed.

Wirings 4a and 4b provided on the substrate 3 and an excitation electrode pattern 2a provided on the piezoelectric vibrator 1;
2b is electrically connected by a connection material 9 such as a conductive adhesive or an anisotropic conductive sheet. The convex portion 8 provided on the substrate 3 restricts a region flowing into the gap between the piezoelectric vibrator 1 and the substrate 3 of the sealing material 7 applied to the outer peripheral portion 1 a of the piezoelectric vibrator 1. In this case, since the convex portion 8 is provided on the outer peripheral side of the electrode patterns 2a and 2b of the piezoelectric vibrator 1, the sealing material 7 can be prevented from adhering to the electrode patterns 2a and 2b.

  The metal wiring 4a, 4b provided on the substrate 3 and the excitation electrode patterns 2a, 2b provided on the piezoelectric vibrator 1 due to the convex portion 8 are connected to a connecting material such as a conductive adhesive or an anisotropic conductive sheet. Since the gap between the piezoelectric vibrator 1 and the convex portion 8 becomes very narrow when electrically connected using the piezoelectric element 9, the piezoelectric vibrator 1 is applied when the sealing material 7 is applied to the outer peripheral portion of the piezoelectric vibrator 1. The sealing material 7 flows into the gap between the substrate 3 and the substrate 3 by capillary action. However, at the stepped portion 20 where the convex portion 8 disappears and the gap widens, the sealing material 7 does not flow due to the surface tension, and it can be controlled so as not to flow into the narrow gap between the piezoelectric vibrator 1 and the convex portion 8.

  In addition, since the water repellent film 5 covers only one surface of the piezoelectric vibrator 1 other than the electrode pattern 2a, the water repellent film 5 has a water repellency when the sample liquid is dropped on the electrode pattern 2a. The sample liquid can remain in the electrode pattern 2a due to the effect. Therefore, when there is little sample liquid, it can measure in this way.

  Furthermore, when the QCM sensor is immersed in a container containing sample liquid, the water repellent effect of the water repellent film 5 prevents the components in the sample liquid from adsorbing on the surface of the substrate 3 or the sealing material 7. Therefore, it is possible to prevent the measurement accuracy from deteriorating due to a decrease in the substance to be detected. As described above, when the sample liquid is sufficient in a container such as a beaker, the substrate 3 on which the piezoelectric vibrator 1 is mounted can be immersed in the sample liquid in the container.

  Next, the mounting process of the QCM sensor piezoelectric vibrator in the first embodiment will be described with reference to FIGS. First, as shown in FIG. 2, the piezoelectric vibrator 1 is divided into an arbitrary size by a method such as etching or dicing, and a metal thin film is formed on the quartz plate by a sputtering method or a vacuum evaporation method using a metal mask. Thus, the excitation electrode patterns 2 a and 2 b are formed on the piezoelectric vibrator 1.

  FIG. 3 is a perspective view of the piezoelectric vibrator 1, and the dotted line represents the state of the back surface. The excitation electrode patterns 2a and 2b are formed such that portions that are electrically connected to the metal wirings 4a and 4b provided on the substrate 3 are on the same surface.

  In the present embodiment, a quartz crystal plate is used as the piezoelectric vibrator 1, a 5 mm square and 50 μm thickness is used, and gold is used in a pattern in which the excitation electrode patterns 2a and 2b are 3 mm square. It was formed with a thickness of 2 μm.

  Next, as shown in the sectional view of FIG. 4 and the perspective view of FIG. 5, a copper foil is laminated on the substrate 3 formed of glass or glass fiber and epoxy resin, and the metal wirings 4a and 4b are projected by photolithography and etching. The part 8 is formed simultaneously. Nickel and gold are formed on the surfaces of the metal wirings 4a and 4b and the projections 8 to prevent copper corrosion. Since the convex portion 8 is made of the same member as the metal wirings 4a and 4b, the manufacture is facilitated.

  In addition to the above method, the convex portion 8 can be formed by applying or printing an adhesive such as epoxy or silicone and curing it. The shape surrounds the excitation electrode patterns 2a and 2b of the piezoelectric vibrator 1. Such a circular shape is sufficient, and the shape such as a circle or square is not particularly limited. The convex portion 8 is suitably formed in the piezoelectric vibrator mounting region of the substrate 3 in accordance with the size of the excitation electrode patterns 2 a and 2 b of the piezoelectric vibrator 1.

  In this embodiment, a substrate 3 made of glass fiber having a thickness of 0.5 mm and an epoxy resin is used, and a copper foil having a thickness of 18 μm is laminated to form the metal wirings 4a, 4b and the projections 8 by photolithography and etching. On the surfaces of the metal wirings 4a and 4b and the protrusions 8, nickel was formed with a thickness of 1 μm and gold was formed with a thickness of 0.3 μm by plating.

  Next, as shown in FIG. 6, the electrode patterns 2a and 2b for excitation provided on the piezoelectric vibrator 1 and the metal wirings 4a and 4b provided on the substrate 3 are made of conductive adhesive, anisotropic conductive sheet or the like. Electrical connection is performed using the connection material 9.

  In this embodiment, a conductive adhesive containing conductive particles such as silver and palladium in a silicone adhesive is applied onto the metal wirings 4a and 4b of the substrate 3 with a dispenser, and the electrode pattern 2a for exciting the piezoelectric vibrator 1 is applied. 2b and the wiring 4a and 4b on the board | substrate 3 were aligned, the electrically conductive adhesive was hardened by heat processing, and the electrical connection was performed.

  Next, as shown in FIG. 7, a sealing material 7 such as epoxy, silicone, or polyurethane is applied to the outer peripheral portion of the piezoelectric vibrator 1 using a dispenser, and the sealing material 7 is placed in the gap between the piezoelectric vibrator 1 and the substrate 3. Then, sealing is completed by curing the sealing material 7.

  At this time, as described above, the sealing material 7 that has flown into the gap between the piezoelectric vibrator 1 and the substrate 3 does not flow into the narrow gap between the convex portion 8 provided on the substrate 3 and the piezoelectric vibrator 1. Sealing can be performed without hindering excitation of the vibrator 1.

  In this embodiment, a room temperature curing type silicone adhesive that is soft after curing and does not generate stress that deforms the piezoelectric vibrator 1 is used as the sealing material 7.

  Next, as shown in FIG. 8, a masking tape 6 is attached to the excitation portion of the electrode pattern 2a on the piezoelectric vibrator 1, and then the water repellent film 5 is applied to the entire QCM sensor by spraying and dried, and then the masking tape 6 As a result, the QCM sensor piezoelectric vibrator mounting structure as shown in FIG. 1 can be obtained.

  In the mounting structure of the piezoelectric vibrator for QCM sensor formed by the above method, the water-repellent film 5 covers the portion other than the electrode pattern 2a portion of the piezoelectric vibrator 1, and therefore when the sample liquid is small, the sample liquid is used as the electrode pattern. The sample liquid may be dropped on the portion 2a, and the sample liquid can remain on the electrode pattern 2a due to the water-repellent effect of the water-repellent film 5.

  If there is more sample liquid, the QCM sensor is immersed in a container containing the sample liquid. In this case, the water repellent effect of the water repellent film 5 can prevent the components in the sample liquid from adsorbing on the surface of the substrate 3 or the sealing material 7, so that the substances to be detected are reduced and the measurement accuracy is lowered. Can be prevented. In this way, the usage can be appropriately selected according to the amount of the sample liquid, which is very convenient.

  Next, the mounting structure of the piezoelectric vibrator for a QCM sensor according to the second embodiment of the present invention will be described with reference to the drawings. FIG. 9 shows a cross-sectional view of the mounting structure of the QCM sensor piezoelectric vibrator in the second embodiment of the present invention. As shown in FIG. 9, in the QCM sensor piezoelectric vibrator mounting structure in which the excitation metal patterns 2a and 2b provided on the piezoelectric vibrator 1 are connected to the metal wirings 4a and 4b provided on the board 3, the substrate 3, a water repellent film 5 is provided in the gap between the piezoelectric vibrator 1 and the substrate 3 to prevent the sample liquid from entering, and the water repellent film 5 is provided for excitation in the piezoelectric vibrator 1. The metal patterns 2a and 2b and the metal wirings 4a and 4b on the substrate 3 have an opening.

  The metal wirings 4a and 4b provided on the substrate 3 and the excitation metal patterns 2a and 2b provided on the piezoelectric vibrator 1 are electrically connected by a connection material 9 such as a conductive adhesive or an anisotropic conductive sheet. The sample liquid is prevented from entering the gap between the piezoelectric vibrator 1 and the substrate 3 by the water repellent effect of the water repellent film 5 provided on the substrate 3.

  Even when the wettability between the piezoelectric vibrator 1 and the sample liquid is good, the sample liquid does not enter the gap between the piezoelectric vibrator 1 and the substrate 3 as long as the water repellent film 5 is formed on the substrate 3 side. It is possible to provide an air layer between the vibrator 1 and the substrate 3, and when the QCM sensor is immersed in the sample liquid, one surface of the piezoelectric vibrator 1 touches the sample liquid, and the other surface serves as the air layer. A touching state is obtained.

  Next, a method for mounting the QCM sensor piezoelectric vibrator according to the second embodiment of the present invention will be described with reference to FIGS. 2 to 3 and FIGS. 9 to 13. Here, only the process different from the first embodiment will be described.

  As shown in FIG. 10, in this embodiment, the substrate 3 is not provided with the convex portion 8. Then, as shown in FIG. 11, a masking tape is formed on the metal wirings 4a and 4b at the connection portion between the excitation metal patterns 2a and 2b provided on the piezoelectric vibrator 1 and the metal wirings 4a and 4b provided on the substrate 3. The water-repellent film 5 is formed by applying the substrate 6 and spraying a resin solution in which water-repellent particles are dispersed on the substrate 3 by spraying.

  The water-repellent film 5 may be patterned using an electrodeposition paint type or a photosensitive type, in addition to forming a resin solution in which water-repellent particles are dispersed by spin coating or spray coating.

  As shown in FIG. 12, the opening of the water-repellent film 5 includes a connection portion between the metal patterns 2 a and 2 b on the piezoelectric vibrator 1 and the metal wirings 4 a and 4 b on the substrate 3. The water-repellent film 5 may be formed in a pattern such as a hatched portion without any problem as long as the size is within the outer shape.

  Thereafter, the masking tape 6 is peeled off, whereby an opening can be provided at a connection portion between the metal patterns 2 a and 2 b provided on the piezoelectric vibrator 1 and the metal wirings 4 a and 4 b provided on the substrate 3.

  The excitation metal patterns 2a and 2b provided on the piezoelectric vibrator 1 and the metal wirings 4a and 4b provided on the substrate 3 are electrically connected using a connection material 9 such as a conductive adhesive or an anisotropic conductive sheet. Connection is performed as shown in FIG.

  In the present embodiment, a conductive adhesive containing conductive particles such as silver and palladium in a silicone adhesive is applied onto the metal wirings 4 a and 4 b formed on the substrate 3 by a dispenser, and the excitation formed on the piezoelectric vibrator 1. The metal patterns 2a and 2b for use and the metal wirings 4a and 4b on the substrate 3 were aligned, the conductive adhesive was cured by heat treatment, and electrical connection was performed.

  A configuration as shown in FIG. 13 is conceivable as an example of a method of using the QCM sensor of this embodiment. In FIG. 13, a sample liquid 18 is stored in a container 14, a stirrer 16 is rotated by a magnetic stirrer 15, the sample liquid 18 is stirred, and a specific substance is selectively adsorbed on the piezoelectric vibrator 1. The QCM sensor on which the film is formed is immersed, the change in the frequency of the piezoelectric vibrator 1 at that time is measured by the measuring device 17, and the mass of the substance adsorbed on the sensor film is calculated.

  Further, when the QCM sensor of the second embodiment is immersed in the container 14 filled with the sample liquid 18 as shown in FIG. 14, the outer peripheral portion of the piezoelectric vibrator 1 is not sealed and is between the substrate 3. Although there is a gap, if the gap is about 1 to 20 μm, the sample liquid 18 enters the gap between the piezoelectric vibrator 1 and the substrate 3 due to the water repellent effect of the water repellent film 5 provided on the substrate 3. It does not come, and sufficient performance can be obtained as a QCM sensor.

  By mounting the piezoelectric vibrator 1 on the substrate 3 by the above method, the metal wiring 4 provided on the substrate 3 and the excitation metal pattern 2 provided on the piezoelectric vibrator 1 are electrically conductive adhesive or anisotropic conductive material. It is electrically connected by a connection material 9 such as a sheet, and a structure in which the water repellent film 5 provided on the substrate 3 prevents the sample liquid from entering the gap between the piezoelectric vibrator 1 and the substrate 3 can be obtained. it can.

It is sectional drawing which shows the mounting structure of the piezoelectric vibrator in 1st embodiment of this invention. It is sectional drawing which shows the manufacturing method of the piezoelectric vibrator in 1st embodiment of this invention. It is an external view which shows the manufacturing method of the piezoelectric vibrator in 1st embodiment of this invention. It is sectional drawing which shows the manufacturing method of the board | substrate in 1st embodiment of this invention. It is an external view which shows the manufacturing method of the board | substrate in 1st embodiment of this invention. It is sectional drawing which shows the mounting structure of the piezoelectric vibrator in 1st embodiment of this invention. It is sectional drawing which shows the mounting structure of the piezoelectric vibrator in 1st embodiment of this invention. It is sectional drawing which shows the manufacturing structure of the piezoelectric vibrator in 1st embodiment of this invention. It is sectional drawing which shows the mounting structure of the piezoelectric vibrator in 2nd embodiment of this invention. It is sectional drawing which shows the manufacturing method of the board | substrate in 2nd embodiment of this invention. It is sectional drawing which shows the manufacturing method of the board | substrate in 2nd embodiment of this invention. It is a top view which shows the manufacturing method of the board | substrate in 2nd embodiment of this invention. It is sectional drawing which shows the usage method of the QCM sensor in embodiment of this invention. It is explanatory drawing which shows the usage method of the QCM sensor in embodiment of this invention. It is sectional drawing which shows the mounting structure of the piezoelectric vibrator in a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 2 Metal pattern 3 Substrate 4 Metal wiring 5 Water repellent film 6 Masking tape 7 Sealing material 8 Convex part 9 Connection material 10 Receptor 11 Tetrafluoroethylene pattern 12 Air layer 14 Container 15 Magnetic stirrer 16 Stirrer 17 Measuring instrument 18 Sample liquid 20 Level difference

Claims (8)

In a QCM sensor piezoelectric vibrator mounting structure in which an excitation metal pattern provided on a substantially flat piezoelectric vibrator is connected to a metal wiring provided on the board, at least of the board on the side where the piezoelectric vibrator is mounted. A QCM sensor piezoelectric vibrator mounting structure characterized in that a water-repellent film is provided on the surface. 2. The mounting structure of a piezoelectric vibrator for a QCM sensor according to claim 1, wherein the water repellent film is provided on substantially the entire surface of the substrate. 2. The water-repellent film has an opening in a portion facing the metal pattern of the piezoelectric vibrator, and the metal wiring is disposed on the substrate surface exposed to the opening. Or the mounting structure of the piezoelectric vibrator for QCM sensors of Claim 2. The QCM sensor according to claim 1, wherein an outer peripheral portion of the piezoelectric vibrator and the substrate are sealed with a sealing material, and the water-repellent film is provided on a surface of the sealing material. Mounting structure for piezoelectric vibrators. 5. The piezoelectric vibration for a QCM sensor according to claim 1, wherein the water-repellent film is provided on an exposed surface of the piezoelectric vibrator while avoiding the excitation metal pattern. 6. Child implementation structure. 4. The QCM according to claim 1, wherein the piezoelectric vibrator is mounted on the substrate while maintaining a gap, and the gap communicates with the outside. 5. Mounting structure of piezoelectric vibrator for sensor. 7. The piezoelectric vibrator mounting structure for a QCM sensor according to claim 6, wherein only the metal pattern portion of the piezoelectric vibrator is fixed to the substrate. The mounting structure for a piezoelectric vibrator for a QCM sensor according to any one of claims 1 to 6, wherein the piezoelectric vibrator is a crystal.

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