Surface wave sensor device

Abstract

A surface wave sensor device where an undesired short circuit or deterioration in measurement precision due to liquid adhesion is less likely to occur and that provides highly reliable measurement results. A surface sensor device (1), where elastic surface wave elements (11, 21) are bonded, with thermo-compressive bonding anisotropic conductive sheets (7, 8) in between, on the first major surface (2a) side of a base substrate (2) having first through-hole conductors (5a, 5b, 6a, 6b), electrodes such as IDTs (13, 14) are formed on the first major surface (12a, 22a) side of piezoelectric substrates (12, 22) of the elastic surface wave elements (11, 21), the electrodes being led out to the second major surface (12b, 22) side through second through-hole conductors (16a, 16b, 26a, 26b) arranged in the piezoelectric substrates (12, 22), and the first through-hole conductors (5a, 5b, 5e, 5f) are arranged superposed on the second through-hole conductors (16a, 16b, 26a, 26b) with the thermo-compressive bonding anisotropic conductive sheets (7, 8) in between.

Description

technical field [0001] The present invention relates to a surface wave sensor device capable of detecting a substance to be detected by utilizing changes in the mass load on the surface wave sensor, and particularly relates to a surface wave sensor device suitable for detecting a substance to be detected in a liquid. Background technique [0002] Conventionally, various sensors have been proposed for detecting substances present in liquids. [0003] For example, Patent Document 1 below discloses a substance-in-liquid sensor that detects substances in liquid using surface waves. [0004] FIG. 9 is a schematic front cross-sectional view for explaining the substance-in-liquid detection sensor described in Patent Document 1. FIG. [0005] In the figure, a substance-in-liquid detection sensor 102 is immersed in a solution 101 containing a substance to be detected. The substance-in-liquid detection sensor 102 is composed of a surface wave element. That is, the substance-in-liqu...

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Problems solved by technology

[0006] However, in the measurement method using the substance-in-liquid detection sensor 102, it is necessary to immerse the substance-in-liquid detection sensor 102 in the liquid 101.

Therefore, there is a problem that when only a small amount of the liquid 101 to be measured can be prepared, the substance in the liquid cannot be detected.

[0007] Another problem is that even if a large amount of liquid can be supplied, if the liquid is an expensive liquid, the measurement cost is high.

[0008] In addition, there is a problem that, in the substance-in-liquid detection sensor 102, the liquid 101 is also adhered to areas other than the area where the surface acoustic wave propagates, that is, in the area where the electrode pads and welding wires connected to the IDT electrodes 103 and 104 are arranged. , so the electrical characteristics change and the detection accuracy deteriorates

Therefore, since the die-bonding material 267 is fluid before being cured, there is a problem that attention must be paid to handling, and bonding work is troublesome.

[0021] In addition, in the surface acoustic wave device 251, the surface acoustic wave element 259 is packaged in the area surrounded by the above-mentioned base substrate 252 and the cover material 271, and it is not intended to be used as a surface wave device such as a sensor for detecting substances in liquid.

[0022] As mentioned above, although the surface acoustic wave devices described in Patent Documents 2 and 3 disclose the structure of electrically connecting the surface acoustic wave element to the electrodes on the base substrate, these surface acoustic wave devices are not used to detect use of the substance

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