JP2018189584A - Multi-layered substrate having piezoelectric film, device having piezoelectric film, and method for manufacturing device having piezoelectric film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layered substrate having a piezoelectric film with higher versatility, and a technique related thereto.SOLUTION: The present invention includes: a substrate; a piezoelectric film formed on the substrate; and a trap part capturing a predetermined particle, the substrate and the piezoelectric film having a resonance part which bends and vibrates at a predetermined frequency when a predetermined voltage is applied. When the trap part captures a particle while the resonance part is bending and vibrating, the frequency of the resonance part is changed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer substrate having a piezoelectric film, a device having a piezoelectric film, and a method for manufacturing a device having a piezoelectric film.

  Piezoelectric bodies are widely used for functional electronic parts such as sensors and actuators. As a piezoelectric material, for example, potassium sodium niobate (KNN) is used (see, for example, Patent Documents 1 and 2). In recent years, a piezoelectric body with higher versatility has been strongly demanded.

JP 2007-184513 A JP 2008-159807 A

  An object of the present invention is to provide a multilayer substrate having a piezoelectric film with improved versatility and related technology.

According to one aspect of the invention,
A substrate,
A piezoelectric film formed on the substrate;
A trap section for capturing predetermined particles,
The substrate and the piezoelectric film have a resonance part that bends and vibrates at a predetermined frequency when a predetermined voltage is applied,
When the trap portion captures particles in a state where the resonance portion is flexed and vibrated, a laminated substrate having a piezoelectric film whose frequency of the resonance portion changes and related technology thereof are provided.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the multilayer substrate which has the piezoelectric film which improved versatility, and its related technique.

It is a figure which shows the cross-section of the laminated substrate concerning one Embodiment of this invention. It is a figure which shows the cross-section of the laminated substrate concerning the modification of one Embodiment of this invention. (A) is a figure which shows the cross-section of the laminated substrate concerning the modification of one Embodiment of this invention, (b)-(d) is the board | substrate exposed from the opening of the piezoelectric film which each laminated substrate has, respectively. It is a top view which shows an area | region. It is a figure which shows schematic structure of the device which has a piezoelectric film concerning one Embodiment of this invention. It is a figure which shows the cross-section of the conventional laminated substrate.

<One Embodiment of the Present Invention>
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(1) Configuration of Laminated Substrate As shown in FIG. 1, a laminated substrate 10 according to this embodiment includes a substrate 1, a lower electrode film 2 formed on the substrate 1, and a film formed on the lower electrode film 2. The piezoelectric film (piezoelectric thin film) 3 and the upper electrode film 4 formed on the piezoelectric film 3 are configured as a laminated body.

Si substrate as the substrate 1, having a thermal oxide film or a CVD (Chemical Vapor Deposition) surface oxide film single crystal silicon (SiO ₂ film) 1b is formed such as an oxide film (Si) substrate 1a, i.e., the surface oxide film Can be suitably used. As the substrate 1, as shown in FIG. 2, a Si substrate 1a having an insulating film 1d formed of an insulating material other than SiO _{2 on} its surface can be used. Further, as the substrate 1, it is also possible to use a Si substrate 1a having an exposed Si (100) surface or Si (111) surface, that is, a Si substrate having no surface oxide film 1b or insulating film 1d. Further, as the substrate 1, an SOI (Silicon On Insulator) substrate, a quartz glass (SiO ₂ ) substrate, a gallium arsenide (GaAs) substrate, a sapphire (Al ₂ O ₃ ) substrate, a metal substrate formed of a metal material such as stainless steel. Can also be used. The thickness of the single crystal Si substrate 1a can be set to 300 to 1000 μm, for example, and the thickness of the surface oxide film 1b can be set to 5 to 3000 nm, for example.

  A concave portion 7 having a predetermined depth D is formed on the back surface (surface opposite to the surface on which the piezoelectric film 3 is provided) of the substrate 1 from the back surface side to the front surface side. It has a region where the thickness is thin (hereinafter also referred to as a thin region). The planar shape of the thin region, that is, the planar shape of the recess 7 is circular. The planar shape of the recess 7 may be various shapes such as a rectangle. The concave portion 7 can be formed by removing a part of the substrate 1 using a technique such as Deep-RIE or wet etching.

The lower electrode film 2 can be formed using, for example, platinum (Pt). The lower electrode film 2 is a single crystal film or a polycrystalline film (hereinafter also referred to as a Pt film). The crystals constituting the Pt film are preferably preferentially oriented in the (111) plane orientation with respect to the surface of the substrate 1. That is, it is preferable that the surface of the Pt film (the surface serving as the base of the piezoelectric film 3) is mainly composed of the Pt (111) surface. The Pt film can be formed using a technique such as sputtering or vapor deposition. In addition to Pt, the lower electrode film 2 is made of various metals such as gold (Au), ruthenium (Ru) and iridium (Ir), alloys based on these metals, strontium ruthenate (SrRuO ₃ ) and lanthanum nickelate (LaNiO). It is also possible to form a film using a metal oxide such as ₃ ). In order to improve the adhesion between the substrate 1 and the lower electrode film 2, for example, titanium (Ti), tantalum (Ta), titanium oxide (TiO ₂ ), nickel (Ni), or the like is used as a main component. The adhesion layer 6 is provided. The adhesion layer 6 can be formed using a technique such as sputtering or vapor deposition. The thickness of the lower electrode film 2 can be set to 100 to 400 nm, for example, and the thickness of the adhesion layer 6 can be set to 1 to 200 nm, for example.

The piezoelectric film 3 includes, for example, potassium (K), sodium (Na), niobium (Nb), and an alkali niobium oxide represented by a composition formula (K _1-x Na _x ) NbO ₃ , that is, potassium niobate. A film can be formed using sodium (KNN). The coefficient x [= Na / (K + Na)] in the above composition formula is 0 <x <1, preferably 0.4 ≦ x ≦ 0.7. The piezoelectric film 3 is a KNN polycrystalline film (hereinafter also referred to as a KNN film (KNN thin film) 3). The crystal structure of KNN is a perovskite structure.

The crystals constituting the KNN film 3 are preferably preferentially oriented in the (001) plane orientation with respect to the surface of the substrate 1. That is, it is preferable that the surface of the KNN film 3 (surface serving as the base of the upper electrode film 4) is mainly composed of the KNN (001) surface. For the surface of the substrate 1 (
111) The KNN film 3 is directly formed on the Pt film that is preferentially oriented in the plane orientation, so that the crystals constituting the KNN film 3 are preferentially oriented in the (001) plane orientation with respect to the surface of the substrate 1. Becomes easy. For example, 80% or more of the crystals constituting the KNN film 3 are oriented in the (001) plane orientation with respect to the surface of the substrate 1, and 80% or more of the surface of the KNN film 3 is aligned with KNN (001 ) Surface. The thickness of the KNN film 3 can be set to 0.5 to 5 μm, for example.

The KNN film 3 can be formed using a technique such as sputtering, PLD (Pulsed Laser Deposition), or sol-gel. The composition ratio of the KNN film 3 can be adjusted, for example, by controlling the composition of the target material used during sputtering film formation. The target material can be produced, for example, by mixing and baking K ₂ CO ₃ powder, Na ₂ CO ₃ powder, Nb ₂ O ₅ powder, or the like. In this case, the composition of the target material can be controlled by adjusting the mixing ratio of K ₂ CO ₃ powder, Na ₂ CO ₃ powder, Nb ₂ O ₅ powder, and the like.

  The KNN film 3 may contain elements other than K, Na, Nb, such as copper (Cu), manganese (Mn), lithium (Li), Ta, and antimony (Sb) within a range of 5 at% or less. .

The upper electrode film 4 can be formed using, for example, various metals such as Pt, Au, aluminum (Al), Cu, and alloys thereof. The upper electrode film 4 can be formed using a technique such as sputtering, vapor deposition, plating, or metal paste. The upper electrode film 4 does not significantly affect the crystal structure of the KNN film 3 unlike the lower electrode film 2. Therefore, the material, crystal structure, and film forming method of the upper electrode film 4 are not particularly limited. In order to enhance the adhesion between the KNN film 3 and the upper electrode film 4, for example, an adhesion layer mainly composed of Ti, Ta, TiO ₂ , Ni, or the like may be provided. The thickness of the upper electrode film 4 is, for example, 100 to 5000 nm, and when the adhesion layer is provided, the thickness can be, for example, 1 to 200 nm.

  The laminated substrate 10 includes a trap unit that captures (traps, secures) predetermined particles (fine particles) P. Examples of the predetermined particles P include odor particles, dust such as PM2.5 and pollen.

  The trap portion is configured by providing a sensitive film (adhesive film) 9 on the KNN film 3 located above the thin region of the substrate 1. The sensitive film 9 is formed so that its diameter is smaller than the diameter of the recess 7, and the peripheral edge of the sensitive film 9 is located above the thin region of the substrate 1. The planar shape of the sensitive film 9 is preferably similar to the planar shape of the recess 7 and is, for example, circular. For example, the sensitive film 9 is disposed so that the center thereof substantially coincides with the center of the thin region of the substrate 1. As the sensitive film 9, films formed of various materials according to the particles P to be captured can be used. The sensitive film 9 can be formed using a technique such as sticking.

  When the capture target is PM2.5, as illustrated in FIG. 3A, one or a plurality of through-holes 8 penetrating the substrate 1 in the thickness direction are formed in the thin region of the substrate 1, and the lower portion The trap portion may be formed by forming openings 2a and 3a exposing the through holes 8 in the electrode film 2 and the KNN film 3, respectively. When the adhesion layer 6 is provided, an opening 6 a that exposes the through hole 8 is also formed in the adhesion layer 6.

The through hole 8 is formed in a part of the thin region of the substrate 1, for example, at least the central portion of the thin region. When forming the through-holes 8, it is preferable to form a plurality of the through-holes 8 so as to form a dot pattern as shown in FIG. Moreover, as illustrated in FIG. 3C, a plurality of through holes 8 may be formed so that the planar shape of the through holes 8 is rectangular and the through holes 8 form a mesh pattern. Further, the planar shape of the plurality of through holes 8 may be an ellipse, an ellipse, a triangle, or the like in addition to a circle or rectangle, and the above shapes may be mixed. In the case illustrated in FIGS. 3B and 3C, the plurality of through-holes 8 each have a maximum passing width (diameter) in a planar shape smaller than the size of the particle P to be captured. A plurality of through holes 8 may be formed so as to form a stripe pattern as illustrated in FIG. When the through holes 8 form the pattern illustrated in FIG. 3D, as the plurality of through holes 8, through holes having a minimum passing width smaller than the size of the particles P to be captured are formed. The through hole 8 can be formed using a technique such as laser light irradiation (punching with laser light) or etching.

  The maximum delivery width or the smallest delivery width of the through-holes 8 (hereinafter collectively referred to as “width of the through-hole 8”) is appropriately set depending on the particles P to be captured. When the capture target is PM2.5, the width of the through hole 8 can be set to, for example, 2 μm or less, preferably about 1 μm.

  The planar shapes of the openings 2a, 3a, 6a (hereinafter collectively referred to as the openings 3a etc.) formed in the lower electrode film 2, the KNN film 3, and the adhesion layer 6 are the same shape, for example, circular. It is. These openings 3a and the like are formed so that their diameters are smaller than the diameters of the recesses 7, respectively, and the peripheral edges of the openings 3a and the like are located in the upper part of the thin region. The planar shape of the opening 3a and the like is preferably similar to the planar shape of the recess 7 described above. The openings 3a and the like can be formed using a technique such as etching.

  When a voltage is applied between the lower electrode film 2 and the upper electrode film 4 by the voltage applying means 11a in the piezoelectric film device 30 described later, the multilayer substrate 10 bends and vibrates (vibrates in the bending mode). ) Is configured as follows. Since the KNN film 3 is fixed on the substrate 1 via the lower electrode film 2, the KNN film 3 bends and vibrates, so that the substrate 1, particularly the thin region of the substrate 1 and the peripheral portion of the thin region are also KNN film 3 to bend and vibrate. Thus, the multilayer substrate 10 has a resonance part that vibrates when a voltage is applied by the voltage applying means 11a. A resonance part (vibration part) is mainly constituted by the KNN film 3, the thin region of the substrate 1, and its peripheral part. The lower electrode film 2 and the upper electrode film 4 may be included in the resonance part.

  In this embodiment, since the resonance part bends and vibrates, the frequency design of the resonance part is performed by adjusting at least one of the length of the resonance part (the propagation direction of the vibration) and the thickness of the resonance part. be able to. When the magnitude of the voltage applied by the voltage applying means 11a described later is made constant, by increasing the length of the resonance part or increasing the thickness of the resonance part, the frequency of the resonance part (hereinafter, The resonance frequency can also be increased by reducing the length of the resonance part or by reducing the thickness of the resonance part. The length of the resonance part can be determined by adjusting the diameter of the thin region, that is, the diameter L of the recess 7, for example. The thickness of the resonance part can be determined by adjusting, for example, the thickness T of the substrate 1 in the thin region, that is, the depth D of the recess 7 described above. The depth D of the recess 7 can be adjusted, for example, by controlling the etching conditions (etching amount) when forming the recess 7. The frequency of the resonance part can be, for example, higher than 10 kHz and lower than 1 GHz, preferably about 100 kHz.

An example of a method for manufacturing the laminated substrate 10 will be described. First, the lower electrode film 2 is formed on any main surface of the substrate 1. You may prepare the board | substrate 1 with which the lower electrode film 2 was beforehand formed into a film on either main surface. A KNN film 3 is formed on the lower electrode film 2 by using, for example, a sputtering method. And the recessed part 7 which has the predetermined depth D and the predetermined diameter L is formed in the back surface of the board | substrate 1 by wet etching, for example, and a thin area | region is formed in the board | substrate 1. FIG. Subsequently, a sensitive film is formed on the KNN film 3 located above the thin region of the substrate 1 by sticking or the like to form a trap portion. It should be noted that predetermined portions of the lower electrode film 2, the KNN film 3, and the adhesion layer 6 are removed by etching, for example, to form openings 3a and the like to expose a part of the surface of the thin region of the substrate 1, and then the openings 3a. The trap portion may be formed by irradiating a thin region of the substrate 1 exposed from, for example, a laser beam to form the through hole 8. Thereafter, the upper electrode film 4 is formed on the KNN film 3 to obtain the laminated substrate 10.

(2) Configuration of Piezoelectric Film Element and Piezoelectric Film Device By forming the above-described laminated substrate 10 into a predetermined shape, an element 20 having a piezoelectric film (hereinafter also referred to as a piezoelectric film element) is obtained. And the piezoelectric film device 30 is obtained by connecting the voltage application means 11a and the frequency detection means 11b to the piezoelectric film element 20. FIG. 4 shows a schematic configuration diagram of a device (hereinafter, also referred to as a piezoelectric film device) 30 having a piezoelectric film in the present embodiment. The piezoelectric film device 30 includes at least a piezoelectric film element 20, and a voltage application unit 11 a and a frequency detection unit 11 b connected to the piezoelectric film element 20.

  The voltage applying means 11a is connected between the lower electrode film 2 and the upper electrode film 4 of the piezoelectric film element 20, and a voltage is applied between the lower electrode film 2 and the upper electrode film 4 by the voltage applying means 11a. Thus, the resonance part of the piezoelectric film element 20 (laminated substrate 10) can be flexed and vibrated at a predetermined frequency.

  By connecting the frequency detection means 11b between the lower electrode film 2 and the upper electrode film 4 of the piezoelectric film element 20, the piezoelectric film device 30 can function as a sensor. When the trapping part captures the particles P in a state where a constant voltage is applied between the lower electrode film 2 and the upper electrode film 4 by the voltage application means 11a to cause the resonance part to bend and vibrate, the frequency of the resonance part (resonance) Frequency) changes. By detecting the change in the resonance frequency by the frequency detection means 11b, it is possible to detect the capture of the particles P by the trap portion. The frequency detection unit 11b detects a change in the frequency of at least the resonance part of the KNN film 3 in the resonance part. As the frequency detection means 11b, various known means such as a means for detecting a frequency by impedance measurement can be used.

  Below, the detection method of the particle | grains P using the above-mentioned piezoelectric film device 30 is demonstrated. First, a predetermined voltage is applied between the lower electrode film 2 and the upper electrode film 4 by the voltage applying means 11a, and the resonance part of the piezoelectric film element 20 is flexed and vibrated at a predetermined frequency. When the trap portion captures the particles P in a state where a constant voltage is applied by the voltage applying unit 11a, that is, in a state where the resonance portion is bent and vibrated, the frequency of the resonance portion changes as described above. By detecting the change in the resonance frequency by the frequency detection means 11b, the trapping of the particles P by the trap portion can be detected. The particles P captured by the trap part can be blown off by applying a predetermined voltage by the voltage application means 11a and increasing the vibration of the resonance part (vibrating the resonance part with a large amplitude). Thereby, the change of the above-mentioned resonance frequency by the capture | acquisition of the particle | grains P of a trap part can be reset.

(3) Effects Obtained by the Present Embodiment According to the present embodiment, one or more effects shown below can be obtained.

(A) In this embodiment, since the resonance part is configured to bend and vibrate (bending vibration), the frequency design of the resonance part is changed to the design (for example, thickness and length) of the KNN film 3. Rather, as described above, the change can be made only by changing the diameter L of the recess 7 and the thickness T of the substrate 1 in the thin region, that is, the depth D of the recess 7. For this reason, in this embodiment, frequency design can be performed more easily than, for example, a resonance unit that vibrates in thickness.

In contrast to the present embodiment, as shown in FIG. 5, a crystal resonator or a so-called FBAR (Film
There is a sensor manufactured using a piezoelectric film resonator called a “Bulk Acoustic Resonator”. In these sensors, when a detection target adheres to the sensing region of the crystal resonator or the FBAR, the crystal piece included in the crystal resonator or the piezoelectric film included in the FBAR vibrates in thickness. The resonance frequency of a general crystal resonator is about 10 kHz, and the resonance frequency of a general FBAR is about 1 GHz. The frequency design of the crystal resonator and the FBAR is performed by changing the thickness of the crystal piece and the piezoelectric film. When the thickness of the crystal piece and the piezoelectric film is increased, the resonance frequency is lowered, and the frequency of the crystal piece and the piezoelectric film is reduced. As the thickness decreases, the resonance frequency increases.

  For example, if the resonance frequency of the crystal resonator is set to 100 kHz, the thickness of the crystal piece needs to be reduced to about 50 to 100 μm. When the crystal piece is thin, the crystal piece is easily damaged when an impact or vibration is applied to the crystal piece when the crystal unit is manufactured, when the crystal unit is mounted on the device, or after mounting. As described above, when a quartz resonator is used, it is difficult to design the frequency because it is difficult to sufficiently reduce the thickness of the quartz piece.

  On the other hand, in the FBAR, the thickness of the piezoelectric film can be sufficiently reduced to about 1 μm, and the resonance frequency can be sufficiently increased as described above. However, since the resonance frequency of a general FBAR is too high, a peripheral circuit that captures a change in the resonance frequency becomes expensive and versatility is reduced. For this reason, if the resonance frequency of the FBAR is to be lowered to, for example, about 100 kHz, it is necessary to increase the thickness of the piezoelectric film, which may increase the manufacturing cost of the FBAR or reduce the productivity. As described above, when FBAR is used, it is difficult to appropriately increase the thickness of the piezoelectric film, and thus it is difficult to perform frequency design.

(B) According to the present embodiment, since the frequency design of the resonance part can be easily performed as described above, for example, the resonance frequency (10 kHz) of a general crystal resonator and the resonance frequency of a general FBAR ( It is possible to easily form a resonance part having a resonance frequency between 1 GHz and 1 GHz. As a result, the versatility of the piezoelectric film device 30 manufactured by processing the laminated substrate 10 having the piezoelectric film 3 can be enhanced.

(C) According to the present embodiment, the frequency of the resonance unit can be set to about 100 kHz, for example. When, for example, a sensor is manufactured as the piezoelectric film device 30 by processing the multilayer substrate 10 according to the present embodiment, the sensitivity of the sensor depends on the resonance frequency, and the higher the resonance frequency, the higher the sensitivity of the sensor. . A resonance frequency of about 100 kHz is particularly preferable because a sufficiently sensitive sensor can be obtained and the above-described peripheral circuit can be made inexpensive.

(D) Since the filter part is formed by providing the sensitive film 9 or the predetermined through-hole 8 is provided in the substrate 1 and the particles P are captured, the particles P can be screened, and there are a plurality of types. Among these particles, only predetermined particles P to be captured can be selected.

<Other embodiments>
The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

<Preferred embodiment of the present invention>
Hereinafter, preferred embodiments of the present invention will be additionally described.

(Appendix 1)
According to one aspect of the invention,
A substrate,
A piezoelectric film formed on the substrate;
A trap section for capturing predetermined particles,
The substrate and the piezoelectric film have a resonance part that bends and vibrates at a predetermined frequency when a predetermined voltage is applied,
When the trap portion captures particles in a state where the resonance portion is bent and vibrated, a multilayer substrate having a piezoelectric film in which the frequency of the resonance portion changes is provided.

(Appendix 2)
The substrate of appendix 1, preferably,
The trap portion is formed by providing a sensitive film that captures predetermined particles on the piezoelectric film.

(Appendix 3)
The substrate of appendix 1, preferably,
The trap portion is provided with a through-hole that penetrates the substrate in the thickness direction and has at least one of a maximum delivery width or a delivery minimum width smaller than the size of a particle to be captured, and the piezoelectric film , An opening for exposing the through hole is provided.

(Appendix 4)
The substrate of appendix 3, preferably,
A plurality of the through holes are formed so as to form a dot pattern, and the maximum width of the through holes is smaller than the size of the particles to be captured.

(Appendix 5)
The substrate of appendix 3, preferably,
A plurality of the through holes are formed so as to form a stripe pattern or a lattice pattern, and the minimum width of the through holes is smaller than the size of the particles to be captured.

(Appendix 6)
The substrate according to any one of appendices 1 to 5, preferably,
The frequency of the resonance part is adjusted by adjusting the thickness of the substrate.

(Appendix 7)
The substrate according to any one of appendices 1 to 5, preferably,
On the back surface of the substrate, a recess having a predetermined depth is formed from the back surface side to the front surface side,
The frequency of the resonance part is adjusted by adjusting at least one of the depth of the recess and the length of the recess in the vibration propagation direction of the resonance part.

(Appendix 8)
The substrate according to any one of appendices 1 to 7, preferably,
The frequency of the resonance part is higher than 10 kHz and lower than 1 GHz.

(Appendix 9)
The substrate according to any one of appendices 1 to 8, preferably,
The particles are odor particles and dust (PM2.5, pollen, etc.).

(Appendix 10)
The substrate according to any one of appendices 1 to 9, preferably,
The piezoelectric film is a film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K _1-x Na _x ) NbO ₃ (0 <x <1).

(Appendix 11)
According to another aspect of the invention,
A substrate,
An electrode film formed on the substrate;
A piezoelectric film formed on the electrode film;
A trap section for capturing predetermined particles,
The substrate and the piezoelectric film have a resonance part that bends and vibrates at a predetermined frequency when a predetermined voltage is applied,
An element having a piezoelectric film that changes the frequency of the resonance part when the trap part captures particles in a state where the resonance part is bent and vibrated is provided.

(Appendix 12)
According to yet another aspect of the invention,
A substrate,
A lower electrode film formed on the substrate;
A piezoelectric film formed on the lower electrode film;
An upper electrode film formed on the piezoelectric film;
A trap section for capturing predetermined particles;
The resonance part of the substrate and the piezoelectric film is connected to a predetermined frequency by applying a voltage between the lower electrode film and the upper electrode film, connected between the lower electrode film and the upper electrode film. Voltage applying means for bending and vibrating at
A frequency detection means connected between the lower electrode film and the upper electrode film and detecting at least the frequency of the resonance part; and
When the trap portion captures particles in a state where the resonance portion is bent and vibrated by applying a constant voltage by the voltage application means, the frequency detection means changes the frequency of the resonance portion (resonance frequency). A device having a piezoelectric film to detect is provided.

(Appendix 13)
According to yet another aspect of the invention,
Forming a lower electrode film on the substrate;
Forming a piezoelectric film on the lower electrode film;
Forming an upper electrode film on the piezoelectric film;
Forming a trap part for capturing predetermined particles;
A voltage applying means for applying a voltage between the lower electrode film and the upper electrode film to bend and vibrate the resonance part of the substrate and the piezoelectric film is provided between the lower electrode film and the upper electrode film. Connecting, and
Frequency detection means for detecting a change in the frequency of the resonance part (resonance frequency) when the trap part captures particles in a state where the resonance part is bent and vibrated by applying a constant voltage by the voltage application means. Connecting the lower electrode film to the upper electrode film, and a method for manufacturing a device having a piezoelectric film.

1 Substrate 3 Piezoelectric film (KNN film)
10 Laminated substrate 20 (having piezoelectric film) Piezoelectric film element 30 Piezoelectric film device

Claims (7)

A substrate,
A piezoelectric film formed on the substrate;
A trap section for capturing predetermined particles,
The substrate and the piezoelectric film have a resonance part that bends and vibrates at a predetermined frequency when a predetermined voltage is applied,
A laminated substrate having a piezoelectric film in which the frequency of the resonance portion changes when the trap portion captures particles in a state where the resonance portion is bent and vibrated.   The multilayer substrate having a piezoelectric film according to claim 1, wherein the trap portion is formed by providing a sensitive film that captures predetermined particles on the piezoelectric film.   The trap portion is provided with a through-hole that penetrates the substrate in the thickness direction and has at least one of a maximum delivery width or a delivery minimum width smaller than the size of a particle to be captured, and the piezoelectric film The multilayer substrate having a piezoelectric film according to claim 1, which is formed by providing an opening for exposing the through hole.   The multilayer substrate having a piezoelectric film according to any one of claims 1 to 3, wherein a frequency of the resonance part is higher than 10 kHz and lower than 1 GHz. 5. The film according to claim ₁ , wherein the piezoelectric film is a film made of an alkali niobium oxide having a perovskite structure represented by a composition formula (K _1-x Na _x ) NbO ₃ (0 <x <1). A laminated substrate having a piezoelectric film. A substrate,
A lower electrode film formed on the substrate;
A piezoelectric film formed on the lower electrode film;
An upper electrode film formed on the piezoelectric film;
A trap section for capturing predetermined particles;
The resonance part of the substrate and the piezoelectric film is connected to a predetermined frequency by applying a voltage between the lower electrode film and the upper electrode film, connected between the lower electrode film and the upper electrode film. Voltage applying means for bending and vibrating at
A frequency detection means connected between the lower electrode film and the upper electrode film and detecting at least the frequency of the resonance part; and
A piezoelectric film that detects a change in the frequency of the resonance unit by the frequency detection unit when the trap unit captures particles in a state where the resonance unit is bent and vibrated by applying a constant voltage by the voltage application unit. Having a device. Forming a lower electrode film on the substrate;
Forming a piezoelectric film on the lower electrode film;
Forming an upper electrode film on the piezoelectric film;
Forming a trap part for capturing predetermined particles;
A voltage applying means for applying a voltage between the lower electrode film and the upper electrode film to bend and vibrate the resonance part of the substrate and the piezoelectric film is provided between the lower electrode film and the upper electrode film. Connecting, and
A frequency detection means for detecting a change in frequency of the resonance portion when the trap portion captures particles in a state where the resonance portion is bent and vibrated by applying a constant voltage by the voltage application means. And a step of connecting between the film and the upper electrode film. A method for manufacturing a device having a piezoelectric film.

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