Detecting sensor

Abstract

To provide a detecting sensor capable of making it difficult to deteriorate performance by influence of a gas corrosion action.SOLUTION: A detecting sensor S100 includes: a piezoelectric vibration part 20 where a reaction electrode 22 to which an object substance in gas is to be attached and a reference electrode 23 to which the object substance is not to be attached are arranged on a sensor substrate 21 being a piezoelectric vibrator; an exterior cover 12 having an opening part for passing the gas and to cover the piezoelectric vibration part 20; and a support substrate 30 for supporting the piezoelectric vibration part 20. In the piezoelectric vibration part 20, the sensor substrate 21 is attached to the support substrate 30 so as to allow the reaction electrode 22 to face the opening part, and a temperature sensor 25 is arranged on a surface on the opposite side of a surface with the reaction electrode 22 and the reference electrode 23 arranged thereon.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sensing sensor. [Background technology]

[0002] Conventionally, a QCM (Quartz Crystal Microbalance) type sensor using a quartz crystal oscillator has been known as a sensor for detecting substances contained in gas. In this sensor, target substances in gas introduced into the sensor adhere to the quartz crystal oscillator, and the type and amount of the adhered target substance are detected (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-139788 Summary of the Invention [Problem to be solved by the invention]

[0004] Gases containing oxygen plasma or oxygen radicals generated during semiconductor manufacturing processes may damage the temperature sensor or its surrounding structure within the sensor, resulting in a deterioration in the performance of the sensor.

[0005] SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a sensor that is less susceptible to performance degradation due to the corrosive effect of gas. [Means for solving the problem]

[0006] The sensing sensor of the present invention comprises a piezoelectric vibration part provided on a sensor substrate which is a piezoelectric vibrator and which has a reaction electrode to which a target substance in a gas adheres and a reference electrode to which the target substance does not adhere, an exterior cover which has an opening through which the gas passes and which covers the piezoelectric vibration part, and a support substrate which supports the piezoelectric vibration part, and the sensor substrate is attached to the support substrate so that the reaction electrode faces the opening, and a temperature sensor is arranged on the side opposite to the side on which the reaction electrode and the reference electrode are arranged.

[0007] The support substrate may have a cavity formed therein for receiving the temperature sensor, and the temperature sensor may be located inside the cavity when the sensor substrate is attached to the support substrate.

[0008] The sensing sensor of the present invention may further include an electrode cover having a through hole formed in a shape larger than the reaction electrode and arranged to cover the sensor substrate with the reaction electrode exposed through the through hole.

[0009] The electrode cover may have a partition wall between the portion covering the reference electrode and the through hole.

[0010] The reaction electrode may be circular, and the through-hole may be elliptical with a minor axis longer than the diameter of the reaction electrode.

[0011] The sensor may further include a clip for fixing the electrode cover to the sensor substrate, and the clip may be an approximately U-shaped member that is attached so as to sandwich a portion of the peripheral edge of the electrode cover and a portion of the peripheral edge of the support substrate when the sensor substrate is sandwiched between the electrode cover and the support substrate.

[0012] The clip may be arranged to clamp a thin portion formed on the peripheral edge of the electrode cover. [Effects of the Invention]

[0013] The present invention has the effect of providing a sensor that is less susceptible to performance degradation due to the corrosive effect of gas. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. [Figure 2] FIG. 2 is a perspective view showing a part of the detection sensor. [Figure 3] FIG. 2 is a schematic diagram showing a cross-sectional structure of a detection sensor. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of a conventional detection sensor. [Figure 5] FIG. 2 is a perspective view of the electrode cover and the sensor substrate as viewed from below. [Figure 6] FIG. 2 is a cross-sectional perspective view of an electrode cover. DETAILED DESCRIPTION OF THE INVENTION

[0015] Fig. 1 is a perspective view of the detection sensor. Fig. 2 is a perspective view showing a part of the detection sensor. Fig. 3 is a schematic diagram showing the cross-sectional structure of the detection sensor. In the following description, terms indicating directions such as "up" and "down" are used depending on the orientation of the object in the drawing.

[0016] The sensing sensor S100 of this embodiment includes a housing 10, a piezoelectric vibration part 20, a support substrate 30, an electrode cover 50, and a base structure 70, as shown in FIGS.

[0017] The operating principle of the sensing sensor S100 is well known and will be briefly described below. In the sensing sensor S100, the piezoelectric vibrator of the piezoelectric vibration unit 20 is cooled by a Peltier element. Gas supplied from the outside and introduced into the sensing sensor S100 comes into contact with the reactive electrode 22, where it is cooled and adheres to the reactive electrode 22. Thereafter, the temperature of the piezoelectric vibrator is increased while the oscillation frequencies f1 and f2 of the reactive electrode 22 and the reference electrode 23, respectively, are acquired. This temperature increase causes the target substance adhered to the reactive electrode 22 to desorb. This desorption results in a significant change in the oscillation frequency f1. Meanwhile, the oscillation frequency f2 of the reference electrode 23 hardly changes at all. The mass and / or type of the target substance is identified based on the difference between the oscillation frequencies f1 and f2, the degree of change in the oscillation frequency f1, etc.

[0018] (Explanation of each part) 1, the housing 10 has a support member 11 and an exterior cover 12. The support member 11 is a member that supports the piezoelectric vibration part 20, the support substrate 30, the electrode cover 50, and the base structure 70 (FIG. 2).

[0019] The exterior cover 12 is attached to the support member 11 so as to cover the piezoelectric vibration part 20, the electrode cover 50, etc. In this example, the exterior cover 12 has a cylindrical shape. An opening 12a is formed on the top surface of the exterior cover 12. The opening 12a is a portion through which gas containing the target substance passes. The gas is not limited to a specific target, but one example is a highly corrosive halogen-based gas generated in semiconductor manufacturing equipment that performs plasma etching.

[0020] The piezoelectric vibration part 20 includes a sensor substrate 21 and a temperature sensor 25. In this example, the sensor substrate 21 is formed into a generally circular outline shape, as shown in Figures 1 and 2. The sensor substrate 21 is a quartz crystal vibration plate that is a piezoelectric vibrator.

[0021] 2, the sensor substrate 21 has a reaction electrode 22 and a reference electrode 23. The reaction electrode 22 and the reference electrode 23 are formed on the upper surface of the sensor substrate 21. As shown in FIG. 3, the sensor substrate 21 is attached to the support substrate 30 with the reaction electrode 22 and the reference electrode 23 facing the opening 12a.

[0022] The reaction electrode 22 is an electrode to which a target substance contained in the gas adheres. As shown in FIG. 3, the reaction electrode 22 is disposed in a position facing the opening 12a. The reference electrode 23 is formed in a position adjacent to the reaction electrode 22 on the upper surface of the sensor substrate 21. The reference electrode 23 is an electrode to which a target substance in the gas does not adhere. Both the reaction electrode 22 and the reference electrode 23 have, for example, a circular outline.

[0023] The temperature sensor 25 is a sensor for detecting the temperature of the sensor substrate 21. Based on the output value of the temperature sensor 25, the operation of a Peltier element (details below) is controlled, and the temperature of the sensor substrate 21, which is a quartz oscillator, is adjusted.

[0024] 2 and 3, the support substrate 30 is a member that supports the piezoelectric vibration part 20. One example of the support substrate 30 is an LTCC (Low Temperature Co-fired Ceramics) substrate. A cavity 31 is formed in the support substrate 30. The cavity 31 is a recess that receives the temperature sensor 25. The cavity 31 is carved in the thickness direction of the support substrate 30.

[0025] The base structure 70 includes an oscillation control circuit (not shown) and a Peltier element 72 (see FIG. 3). The oscillation control circuit is a circuit for oscillating the piezoelectric vibrator. The Peltier element 72 is a component for cooling the piezoelectric vibrator. The Peltier element 72 is provided so as to be in thermal contact with a part of the support member 11.

[0026] (corrosion problems) FIG. 4 is a diagram showing an example of the configuration of a conventional sensing sensor. In this conventional configuration, a temperature sensor is provided on the upper surface of a sensor substrate 121. In this case, oxygen plasma or oxygen radicals generated, for example, during a semiconductor manufacturing process, enter the sensing sensor S101 through the opening 112a (see arrow A). Such oxygen plasma or oxygen radicals may corrode the temperature sensor 125 or the conductive adhesive that adheres it. Furthermore, it is possible that the oxygen plasma or oxygen radicals may reach not only the reaction electrode 122 but also the reference electrode 123, damaging the reference electrode 123. Such corrosion is undesirable because it shortens the life of the sensing sensor S101 and reduces its performance.

[0027] In the configuration of this embodiment, the temperature sensor 25 is disposed on the surface opposite to the surface on which the reaction electrode 22 and the reference electrode 23 are provided. That is, the temperature sensor 25 is disposed on the lower surface of the sensor substrate 21.

[0028] When the sensor substrate 21 is attached to the support substrate 30, the temperature sensor 25 is located inside the cavity 31. Specifically, as an example, the temperature sensor 25 and the conductive adhesive placed in contact with it are arranged so as to fit within the cavity 31. The cavity 31 is covered by the sensor substrate 21. With this configuration, oxygen plasma and oxygen radicals are less likely to come into contact with the temperature sensor 25 and the conductive adhesive compared to a configuration in which the temperature sensor 25 is placed on the upper surface of the sensor substrate 21, and as a result, corrosion of the temperature sensor 25 and the conductive adhesive can be prevented.

[0029] As shown in FIGS. 2 and 3, the electrode cover 50 is a member that covers the piezoelectric vibration part 20. The electrode cover 50 is formed into a disk shape overall. The electrode cover 50 has a through hole 51. The through hole 51 is formed larger than the reaction electrode 22. In this example, the through hole 51 is also formed larger than the opening 12a. When the electrode cover 50 is attached to the piezoelectric vibration part 20, the reaction electrode 22 is exposed through the through hole 51. With this configuration, even when the electrode cover 50 is attached to the piezoelectric vibration part 20, the target substance in the gas adheres to the reaction electrode 22, allowing the detection sensor S100 to detect the target substance.

[0030] In the present embodiment, for example, the through-hole 51 is disposed such that the center of an ellipse coincides with the center of the circle of the reaction electrode 22. The through-hole 51 is elliptical in shape, with its minor axis longer than the contour of the reaction electrode 22, specifically, longer than the diameter of the circle of the reaction electrode 22. With this configuration, the through-hole 51 can be formed large relative to the circular reaction electrode 22, and therefore a large area of ​​the sensor substrate 21 can be secured that is not constrained by the electrode cover 50, enabling the piezoelectric vibrator of the sensor substrate 21 to vibrate satisfactorily.

[0031] FIG. 5 is a perspective view of the electrode cover and the sensor board as viewed from below. FIG. 6 is a cross-sectional perspective view of the electrode cover. As shown in FIG. 5, the electrode cover 50 has a recess 53 and a partition wall 54. The recess 53 and the partition wall 54 are provided on the underside of the electrode cover 50. The recess 53 does not penetrate the material of the electrode cover 50, but is a structural portion recessed in the thickness direction of the electrode cover 50. The recess 53 is formed in an area that covers the reference electrode 23. For example, the recess 53 is formed to have the same contour shape as the through-hole 51.

[0032] The partition wall 54 separates the recess 53, which is the portion that covers the reference electrode, from the through-hole 51. In this example, the partition wall 54 is configured to abut against the upper surface of the sensor substrate 21, as shown in Fig. 3. The formation of this partition wall 54 prevents oxygen plasma and oxygen radicals from entering the side of the reference electrode 23, thereby preventing corrosion and deterioration of the reference electrode 23.

[0033] (Attachment of the sensor board 21 and the electrode cover 50) As shown in Fig. 2, a thin portion 55 and a cutout portion 56 are formed on the periphery of the electrode cover 50. The thin portion 55 is a portion where the electrode cover 50 is formed to be thinner. As an example, the thin portion 55 is formed so as to extend in the radial direction on the upper surface of the electrode cover 50. The cutout portion 56 is a portion where the periphery of the electrode cover 50 is partially cut out.

[0034] The sensor substrate 21 and the electrode cover 50 may be fixed to the support substrate 30 by any method, but in this embodiment, clips 41 are used as an example. The clips 41 are members formed in a substantially U-shape. The clips 41 are formed, for example, from an elastically deformable conductive material (specifically, metal). In this embodiment, with the sensor substrate 21 sandwiched between the electrode cover 50 and the support substrate 30, multiple clips 41 are attached so as to sandwich part of the periphery of the electrode cover 50 (particularly the thin-walled portion 55) and part of the periphery of the support substrate 30, thereby fixing the sensor substrate 21 and the electrode cover 50.

[0035] The clips 41 are attached so as to move radially inward relative to the thin-walled portions 55. Some of the clips 41 are attached at the positions of the notches 56. These clips 41 do not apply force to the electrode cover 50, but fix the sensor substrate 21 to the support substrate 30. These clips 41 also have the function of contacting the electrode patterns formed on the sensor substrate 21 and the electrode patterns formed on the support substrate 30, electrically connecting the electrode patterns to each other. The configuration of this embodiment has the advantage that the electrode cover 50 can be easily attached alone with the sensor substrate 21 mounted. Furthermore, the clips 41 do not apply large pressure to the components, and therefore excessive pressure is not applied to the piezoelectric vibration part 20.

[0036] (Effect of the S100 sensor) As described above, in the sensing sensor S100 of this embodiment, the temperature sensor 25 is provided on the underside of the sensor substrate 21, and therefore, compared to a configuration in which the temperature sensor 25 is arranged on the upper surface of the sensor substrate 21 as described above, oxygen plasma and oxygen radicals are less likely to come into contact with the temperature sensor 25 and the conductive adhesive, and as a result, corrosion of the temperature sensor 25 and the conductive adhesive can be prevented.

[0037] Furthermore, in the configuration of this embodiment, even if the temperature sensor 25 is provided on the underside of the sensor substrate 21, the sensor substrate 21 is configured to be located in the cavity 31, so the thickness of the sensor substrate 21 and the support substrate 30 does not increase when stacked.

[0038] Furthermore, according to the configuration of this embodiment, the electrode cover 50 is provided, which prevents corrosion of the reference electrode 23, and can suppress deterioration in performance and shortening of the life of the detection sensor S100.

[0039] In addition, in the configuration of this embodiment, the electrode cover 50 and the sensor substrate 21 are fixed by the clip 41. Therefore, even if the components of the detection sensor S100 expand or contract due to a change in temperature, the clip 41 elastically deforms, and the effect of alleviating the stress generated in each component is obtained.

[0040] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0041] 10. Cabinet 11 Support member 12 Exterior cover 20 Piezoelectric vibration part 21 Sensor board 22 Reaction electrode 23 Reference electrode 25 Temperature Sensor 30 Support substrate 31 Cavity 41 clips 50 Electrode cover 51 Through hole 53 Recess 54 Partition Wall 55 Thin-walled section 56 Notch 70 Base Structure 72 Peltier element S100 detection sensor

Claims

1. a piezoelectric vibrating section provided on a sensor substrate, the piezoelectric vibrator being a reaction electrode to which a target substance in a gas adheres and a reference electrode to which the target substance does not adhere; an exterior cover that has an opening through which the gas passes and covers the piezoelectric vibration unit; a support substrate that supports the piezoelectric vibration portion; Equipped with the sensor substrate is attached to the support substrate so that the reaction electrode faces the opening, and a temperature sensor is disposed on a surface opposite to a surface on which the reaction electrode and the reference electrode are provided. Sensing sensor.

2. a cavity for receiving the temperature sensor is formed in the support substrate, and the temperature sensor is located inside the cavity when the sensor substrate is attached to the support substrate; The sensing sensor according to claim 1 .

3. an electrode cover having a through-hole formed in a shape larger than the reaction electrode and arranged to cover the sensor substrate with the reaction electrode exposed through the through-hole; The sensing sensor according to claim 1 or 2.

4. The electrode cover is a partition wall is provided between the portion covering the reference electrode and the through hole; The sensing sensor according to claim 3 .

5. The reaction electrode is circular, The through-hole is elliptical in shape with a minor axis longer than the diameter of the reaction electrode. The sensing sensor according to claim 3 .

6. a clip for fixing the electrode cover to the sensor substrate; The clip is a substantially U-shaped member attached so as to sandwich a part of the peripheral edge of the electrode cover and a part of the peripheral edge of the support substrate in a state in which the sensor substrate is sandwiched between the electrode cover and the support substrate; The sensing sensor according to claim 3 .

7. The clip is arranged to pinch a thin portion formed on the peripheral edge of the electrode cover. The sensing sensor according to claim 6.

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