Method for manufacturing piezoelectric film bonded substrate

Abstract

To provide a high-performance piezoelectric-body film joint substrate in which piezoelectric films of two or more types are provided in superimposition with each other on the same substrate, and a manufacturing method thereof.SOLUTION: A piezoelectric-body film joint substrate (100) includes a substrate (33), a substrate electrode (34) provided on the substrate (33), a first piezoelectric-body film (27) stuck on the substrate electrode (34) and including a first piezoelectric film (25) and a first upper electrode film (26) formed on the first piezoelectric film, and a second piezoelectric-body film (17) stuck on the first upper electrode film (26) and including a second piezoelectric film (15) different from the first piezoelectric film (25) and a second upper electrode film (16) formed on the second piezoelectric film (15).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a piezoelectric film-bonded substrate and a method for manufacturing the same. [Background technology]

[0002] Conventionally, a laminate of a plurality of different types of piezoelectric films has been proposed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-190890 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional devices, when a plurality of piezoelectric films of different types are stacked on the same substrate, it is not possible to obtain a high-performance device having a plurality of piezoelectric films.

[0005] An object of the present disclosure is to provide a high-performance piezoelectric film bonded substrate in which two or more types of piezoelectric films are stacked on the same substrate, and a method for manufacturing the same. [Means for solving the problem]

[0007] The method for manufacturing a piezoelectric film bonded substrate of the present disclosure is characterized by peeling off a first piezoelectric film formed on a first substrate and having a first piezoelectric film and a first electrode film provided on the first piezoelectric film, and a second piezoelectric film formed on a second substrate and having a second piezoelectric film and a second electrode film provided on the second piezoelectric film, from the first substrate and the second substrate, respectively, and bonding the first piezoelectric film onto an electrode formed on a third substrate different from both the first substrate and the second substrate, and bonding the second piezoelectric film onto the first piezoelectric film. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a high-performance piezoelectric film bonded substrate in which two or more types of piezoelectric films are stacked on the same substrate, and a method for manufacturing the same. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a side view schematically showing the structure of a piezoelectric film bonded substrate according to Embodiment 1. FIG. [Figure 2] FIG. 2 is a top view schematically showing the structure of the piezoelectric film bonded substrate of FIG. [Figure 3] 3 is a cross-sectional view of the piezoelectric film bonded substrate taken along line S3-S3 in FIG. 2. [Figure 4] 3 is a flowchart showing a method for manufacturing a piezoelectric film bonded substrate according to the first embodiment. [Figure 5] (A) and (B) are a top view and a cross-sectional view schematically showing the structure of a PZT epitaxially grown film in step ST101 of FIG. 4, and (C) and (D) are a top view and a cross-sectional view schematically showing the structure of a PZT epitaxially grown film in step ST102 of FIG. 4. [Figure 6] (A) and (B) are a top view and a cross-sectional view schematically showing the structure of the AlN epitaxially grown film in step ST104 of Figure 4, and (C) and (D) are a top view and a cross-sectional view schematically showing the structure of the AlN epitaxially grown film in step ST105 of Figure 4. [Figure 7] 5(A) and 5(B) are cross-sectional views schematically showing the process of holding a plurality of PZT piezoelectric films in step ST103 of FIG. [Figure 8] 5(A) and 5(B) are cross-sectional views schematically showing the process of holding a plurality of AlN piezoelectric films in step ST106 of FIG. [Figure 9]4. (A) is a cross-sectional view that schematically shows the process of attaching the AlN piezoelectric film in step ST107 of FIG. 4, and (B) is a top view that shows the state in which the AlN piezoelectric film has been attached. [Figure 10] 4. (A) is a cross-sectional view that schematically shows the process of attaching the PZT piezoelectric film in step ST108 of FIG. 4, and (B) is a top view that shows the state in which the PZT piezoelectric film has been attached. [Figure 11] 10A is a cross-sectional view showing the next manufacturing process of a piezoelectric film bonded substrate, and FIG. 10B is a top view showing the state in which a PZT piezoelectric film has been attached. [Figure 12] 10(A) and 10(B) are a side view and a top view schematically showing the structure of a piezoelectric film bonded substrate according to a modified example of the first embodiment. [Figure 13] 10(A) and 10(B) are a side view and a top view schematically showing the structure of a piezoelectric film bonded substrate according to Embodiment 2. FIG. [Figure 14] FIG. 1 is a cross-sectional view schematically showing the structure of an epitaxially grown film including a PZT piezoelectric film. [Figure 15] FIG. 1 is a cross-sectional view schematically illustrating the structure of an epitaxially grown film including an AlN piezoelectric film. [Figure 16] 13 is a flowchart showing a method for manufacturing the piezoelectric film bonded substrate of FIGS. 12(A) and 12(B). [Figure 17] (A) and (B) are a top view and a cross-sectional view schematically showing the structure of a PZT epitaxially grown film in step ST201 of FIG. 16, and (C) and (D) are a top view and a cross-sectional view schematically showing the structure of a PZT epitaxially grown film in step ST202 of FIG. 16. [Figure 18] (A) and (B) are a top view and a cross-sectional view schematically showing the structure of the AlN epitaxially grown film in step ST204 of Figure 16, and (C) and (D) are a top view and a cross-sectional view schematically showing the structure of the AlN epitaxially grown film in step ST205 of Figure 16. [Figure 19]17(A) and 17(B) are cross-sectional views schematically showing the process of holding a plurality of PZT piezoelectric films in step ST203 of FIG. 16. [Figure 20] 17(A) and 17(B) are cross-sectional views schematically showing the process of holding a plurality of AlN piezoelectric films in step ST206 of FIG. [Figure 21] 16. (A) is a cross-sectional view that schematically shows the process of attaching the AlN piezoelectric film in step ST207 of FIG. 16, and (B) is a top view that shows the state in which the AlN piezoelectric film has been attached. [Figure 22] 16. (A) is a cross-sectional view that schematically shows the process of attaching the PZT piezoelectric film in step ST208 of FIG. 16, and (B) is a top view that shows the state in which the PZT piezoelectric film has been attached. [Figure 23] 10A is a cross-sectional view showing the next manufacturing process of a piezoelectric film bonded substrate, and FIG. 10B is a top view showing the state in which a PZT piezoelectric film has been attached. DETAILED DESCRIPTION OF THE INVENTION

[0010] Piezoelectric film-bonded substrates and manufacturing methods thereof according to embodiments will be described below with reference to the drawings. The following embodiments are merely examples, and various modifications are possible within the scope of this disclosure. In this application, the piezoelectric film-bonded substrate is an intermediate product in which multiple piezoelectric films are provided on the same substrate. The piezoelectric films are preferably single-crystal piezoelectric films, but can also be polycrystalline piezoelectric films.

[0011] By using the piezoelectric film bonded substrate according to the embodiment, a piezoelectric film integrated device having a plurality of piezoelectric bodies can be manufactured. This piezoelectric film integrated device is, for example, an acoustic vibration sensor. An acoustic vibration sensor is a sensor that outputs an acoustic vibration wave and detects the reflected wave of the acoustic vibration wave to detect the state (e.g., distance, shape, movement, etc.) of an object to be detected. An acoustic vibration sensor is also called an "ultrasonic sensor." Generally, and in this application, an acoustic vibration wave is composed of at least one of a sound wave and an ultrasonic wave. That is, an acoustic vibration wave is composed of a sound wave, an ultrasonic wave, or both a sound wave and an ultrasonic wave.

[0012] 1. First embodiment <1-1> Structure of the piezoelectric film bonded substrate 100 Fig. 1 is a side view schematically showing the structure of a piezoelectric film bonded substrate 100 according to embodiment 1. Fig. 2 is a top view schematically showing the structure of the piezoelectric film bonded substrate 100. Fig. 3 is a cross-sectional view of the piezoelectric film bonded substrate 100 of Fig. 2 taken along line S3-S3.

[0013] The piezoelectric film bonded substrate 100 has an SOI substrate 33 as a substrate, and a platinum (Pt) film 34 as an electrode (i.e., substrate electrode) provided on the SOI substrate 33. As shown in Fig. 2, the Pt film 34 is connected to a wiring layer formed on the SOI substrate 33. SOI stands for silicon on insulator. Also, a drive circuit for driving the piezoelectric film bonded substrate 100 to generate acoustic vibration waves, a processing circuit for performing processing using detection signals of the acoustic vibration waves, and the like may be formed within the SOI substrate 33.

[0014] The piezoelectric film bonded substrate 100 has an AlN piezoelectric film 27 as a first piezoelectric film attached to a Pt film 34, which is a substrate electrode, and a PZT piezoelectric film 17 as a second piezoelectric film attached to the AlN piezoelectric film 27. The AlN piezoelectric film 27 has an AlN film 25 as a first piezoelectric film and a Pt film 26 formed thereon as a first upper electrode film. The PZT piezoelectric film 17 has a PZT film 15 as a second piezoelectric film different from the first piezoelectric film (e.g., having a different crystal structure) and a Pt film 16 formed thereon as a second upper electrode film, and is attached to the Pt film 26. The PZT piezoelectric film 17 and the AlN piezoelectric film 27 have different areas. In the first embodiment, the area of ​​the PZT piezoelectric film 17 is smaller than the area of ​​the AlN piezoelectric film 27.

[0015] AlN is aluminum nitride. PZT is lead zirconate titanate. Instead of an AlN piezoelectric film, other piezoelectric films such as lithium tantalate (LiTaO3) or lithium niobate (LiNbO3) may be used as the first piezoelectric film. Instead of a PZT piezoelectric film, other piezoelectric films such as potassium sodium niobate (KNN) or barium titanate (BaTiO3) may be used as the second piezoelectric film. The first and second piezoelectric films are preferably single-crystal piezoelectric films, but may also be polycrystalline piezoelectric films. In the illustrated example, the first piezoelectric film is a piezoelectric that detects acoustic vibration waves (or their reflected waves) and has a lower dielectric constant and higher detection sensitivity than the second piezoelectric film. The second piezoelectric film is a piezoelectric that generates acoustic vibration waves and is preferably a piezoelectric that has a larger piezoelectric constant than the vibration amplitude of the first piezoelectric film and can obtain a larger vibration amplitude.

[0016] Alternatively, the first piezoelectric film, which is the lower piezoelectric film, may have a PZT film and a Pt film, and the second piezoelectric film, which is the upper piezoelectric film, may have an AlN film and a Pt film superimposed thereon.

[0017] As shown in FIG. 1, the piezoelectric film bonded substrate 100 has an insulating film 35a and a wiring film 36a formed thereon, an insulating film 35b and a wiring film 36b formed thereon.

[0018] The SOI substrate 33 includes a Si substrate 30, a silicon oxide (SiO2) portion 31 as an insulating film, and a single-crystal silicon (single-crystal Si) portion 32. A cavity may be formed in the Si substrate 30 by etching the Si substrate 30 in the region of the single-crystal Si portion 32 below the PZT film 15 and the AlN film 25 (i.e., the region overlapping the piezoelectric film). The SiO2 portion 31 and the single-crystal Si portion 32 located in the region where the cavity is formed function as a diaphragm. Alternatively, a substrate made of other materials, such as a glass substrate or an organic film substrate, may be used instead of the SOI substrate 33. Acoustic vibration waves generated in the PZT film 15 are output from the cavity, and the AlN film 25 detects the reflected acoustic vibration waves through the cavity.

[0019] The thickness of the PZT film 15 is generally in the range of 10 nm to 10 μm, preferably in the range of 100 nm to 5 μm. The thickness of the AlN film 25 is generally in the range of 10 nm to 10 μm, preferably in the range of 100 nm to 2 μm. The Pt film 34 is formed on the upper surface of the SOI substrate 33. The surface (upper surface) of the Pt film 34 and the AlN piezoelectric film 27 are bonded by intermolecular forces. The surface of the Pt film 26 of the AlN piezoelectric film 27 and the PZT piezoelectric film 17 are bonded by intermolecular forces. No adhesive is required for these bonds. To bond these films well by intermolecular forces, it is desirable that the surface roughness of the bonding surface of the AlN piezoelectric film 27, the bonding surface of the PZT piezoelectric film 17, and the Pt film 34 and the Pt film 26 be 10 nm or less. For this purpose, the surfaces of the Pt film 34 and the Pt film 26 may be smoothed. Furthermore, the interface between the bonding surface of the AlN piezoelectric film 27 and the Pt film 34 is 10 nm or less. Furthermore, it is desirable that the surface area of ​​the Pt film 34 is larger than the surface area of ​​the bonding surface of the AlN piezoelectric film 27. This structure allows for a larger tolerance for error in bonding accuracy when bonding the AlN piezoelectric film 27 to the Pt film 34.

[0020] 《1-2》Manufacturing method In manufacturing the piezoelectric film bonded substrate 100, an AlN piezoelectric film 27 formed on a growth substrate 21 and having an AlN film 25 and a Pt film 26 provided thereon, and a PZT piezoelectric film 17 formed on a growth substrate 11 and having a PZT film 15 and a Pt film 16 provided thereon, are peeled off from the growth substrates 21 and 11, respectively, and the AlN piezoelectric film 27 is attached to a Pt film 34, which is an electrode formed on an SOI substrate 33 that is different from both the growth substrates 21 and 11, and the PZT piezoelectric film 17 is attached to the AlN piezoelectric film 27.

[0021] FIG. 4 is a flowchart showing a method for manufacturing a piezoelectric film bonded substrate 100. FIGS. 5(A) and 5(B) are a top view and a cross-sectional view, respectively, schematically showing the structure of a PZT epitaxially grown film in step ST101 of FIG. 4. FIGS. 5(C) and 5(D) are a top view and a cross-sectional view, respectively, schematically showing the structure of a PZT epitaxially grown film in step ST102 of FIG. 4. FIGS. 6(A) and 6(B) are a top view and a cross-sectional view, respectively, schematically showing the structure of an AlN epitaxially grown film in step ST104 of FIG. 4. FIGS. 6(C) and 6(D) are a top view and a cross-sectional view, respectively, schematically showing the structure of an AlN epitaxially grown film in step ST105 of FIG. 4. FIGS. 7(A) and 7(B) are cross-sectional views schematically showing the holding process of a plurality of PZT piezoelectric films 17 in step ST103 of FIG. 4. 8(A) and 8(B) are cross-sectional views schematically showing the process of holding a plurality of AlN piezoelectric films 27 in step ST106 of FIG. 4. FIG. 9(A) is a cross-sectional view schematically showing the process of bonding the AlN piezoelectric films 27 in step ST107 of FIG. 4, and FIG. 9(B) is a top view showing the state where the AlN piezoelectric films 27 have been bonded. FIG. 10(A) is a cross-sectional view schematically showing the process of bonding the PZT piezoelectric films 17 in step ST108 of FIG. 4, and FIG. 10(B) is a top view showing the state where the PZT piezoelectric films 17 have been bonded. FIG. 11(A) is a cross-sectional view showing the next manufacturing process of a piezoelectric film bonded substrate, and FIG. 11(B) is a top view showing the state where the PZT piezoelectric films 17 have been bonded.

[0022] First, as shown in Figures 5(A) and (B), a sacrificial layer 14, a PZT film 15, and a Pt film 16 are epitaxially grown on a growth substrate (step ST101), and as shown in Figures 5(C) and (D), the PZT film 15 and the Pt film 16 are etched into circular shapes to form a plurality of PZT piezoelectric films 17 (step ST102).

[0023] 6(A) and (B), a sacrificial layer 24, an AlN film 25, and a Pt film 26 are epitaxially grown on another growth substrate (step ST104), and as shown in FIGS. 6(C) and (D), the AlN film 25 and the Pt film 26 are etched into circular shapes to form multiple AlN piezoelectric films 27 (step ST105).

[0024] 7(A) and (B), a plurality of (four in the illustrated example) PZT piezoelectric films 17, each consisting of a PZT film 15 and a Pt film 16, are held by a stamp 42 as a holding member, and are peeled off by etching the sacrificial layer (step ST103). Also, as shown in FIGS. 8(A) and (B), a plurality of (four in the illustrated example) AlN piezoelectric films 27, each consisting of an AlN film 25 and a Pt film 26, are held by a stamp 41 as a holding member, and are peeled off by etching the sacrificial layer (step ST106).

[0025] Next, as shown in FIGS. 9A and 9B, one of the plurality of AlN piezoelectric films 27 held by the stamp 41 is attached onto the Pt film 34 (step ST107).

[0026] 10(A) and 10(B), one of the multiple PZT piezoelectric films 17 held by the stamp 42 is attached to the Pt film 26 of the AlN piezoelectric film 27 attached to the Pt film 34 (step ST108). After attachment, an annealing process may be added to strengthen the attachment between the Pt and the piezoelectric film.

[0027] As shown in FIGS. 9A and 9B, in the first embodiment, contact electrodes and wiring patterns are formed on an SOI substrate 33 using Pt, an AlN piezoelectric film 27 is attached, and then a PZT piezoelectric film 17 is attached to the Pt film 26, which is the upper electrode film. When the AlN piezoelectric films 27 held by the stamp 41 are in a 2x2 matrix, they are attached to different SOI substrates 33 in the order of #1, #2, #3, and #4 in the figure. In this case, the AlN piezoelectric film 27 with the largest diameter is attached first. In this example, four SOI substrates 33 are prepared for four piezoelectric films. As shown in FIGS. 10A and 10B, a PZT piezoelectric film 17 is attached to the AlN piezoelectric film 27. The films are attached in the order of #1, #2, #3, and #4, and as shown in Figure 11(A), the PZT piezoelectric film 17 is attached on top of the AlN piezoelectric film 27, so the stamp 42, which is the holding member, can be attached without interfering with the AlN piezoelectric film 27.

[0028] Next, an insulating film 35a and a wiring film 36a are formed on the PZT film 15 and the Pt film 16, and an insulating film 35b and a wiring film 36b are formed on the AlN film 25 and the Pt film 26.

[0029] When bonding, the efficiency of the piezoelectric vibration driving of the PZT film 15 and the piezoelectric vibration receiving of the AlN film 25 is maximized by arranging the hexagonal crystal of AlN and the cubic crystal of PZT so that the c-axes are parallel to each other.

[0030] 1-3 Variations 12(A) and 12(B) are a side view and a top view schematically showing the structure of a piezoelectric film bonded substrate 100a according to a modified example of Embodiment 1. The piezoelectric film bonded substrate 100a differs from the piezoelectric film bonded substrate 100 shown in FIGS. 1 to 3 in that the AlN piezoelectric film 27a and the PZT piezoelectric film 17a have rectangular planar shapes. In all other respects, the piezoelectric film bonded substrate 100a is the same as the piezoelectric film bonded substrate 100.

[0031] Effect 1-4 As described above, in the first embodiment, the PZT piezoelectric film 17 and the AlN piezoelectric film 27, which are difficult to epitaxially grow on the same SOI substrate 33 due to their different lattice constants and crystal structures, are formed on separate growth substrates, peeled off from the growth substrates, and then laminated on a common SOI substrate 33, thereby making it possible to create a high-performance piezoelectric film bonded substrate 100.

[0032] Furthermore, the single-crystal PZT film 15 has a higher piezoelectric constant than a polycrystalline PZT film, making it easy to increase the amplitude of vibration. Furthermore, the single-crystal AlN film 25 has a lower dielectric constant than a polycrystalline AlN film, making it possible to increase the vibration reception sensitivity. However, the PZT film 15 may contain polycrystalline PZT, and the AlN film 25 may contain polycrystalline AlN. In other words, the single-crystallization rates of the PZT film 15 and the AlN film 25 may be 100% or less.

[0033] Furthermore, conventionally, forming heterogeneous piezoelectric films required complex processes such as covering one piezoelectric film with a protective layer and then removing the protective layer after forming the other piezoelectric film, and the application of heat during each process left residual stress strain in the piezoelectric film, resulting in a decrease in efficiency as a sensor.However, the manufacturing method of embodiment 1 makes it possible to form a piezoelectric film bonded substrate and an acoustic vibration sensor without residual stress strain.

[0034] 2. Second Embodiment 2-1 Structure of the piezoelectric film bonded substrate 200 13(A) and 13(B) are a side view and a top view schematically showing the structure of a piezoelectric film bonded substrate 200 according to embodiment 2. In Fig. 13(A) and 13(B), components that are the same as or correspond to those shown in Fig. 1 to Fig. 3 are assigned the same reference numerals as those shown in Fig. 1 to Fig. 3.

[0035] The piezoelectric film bonded substrate 200 has an AlN piezoelectric film 127 as a first piezoelectric film attached to a Pt film 134, and a PZT piezoelectric film 117 as a second piezoelectric film attached to the AlN piezoelectric film 127. The AlN piezoelectric film 127 has a Pt film 126 as a first lower electrode film, an AlN film 25 as a first piezoelectric film formed thereon, and a Pt film 26 as a first upper electrode film formed thereon. The PZT piezoelectric film 117 has a Pt film 116 as a second lower electrode film, a PZT film 15 as a second piezoelectric film different from the first piezoelectric film (e.g., having a different crystal structure), and a Pt film 16 as a second upper electrode film formed thereon, with the Pt film 116 attached to the Pt film 26. The areas of the PZT piezoelectric film 117 and the AlN piezoelectric film 127 are different from each other. In the first embodiment, the area of ​​the PZT piezoelectric film 117 is smaller than the area of ​​the AlN piezoelectric film 127. Other than the above, the structure of the piezoelectric film bonded substrate 200 is the same as that of the piezoelectric film bonded substrate 100. Here, the substrate electrodes are formed from Pt (platinum), but this is not necessarily limited to Pt. For example, the substrate electrodes may be formed from various metals such as gold, aluminum, or copper.

[0036] 《2-2》Manufacturing method Fig. 14 is a cross-sectional view schematically showing the structure of an epitaxially grown film including a PZT piezoelectric film 117. Fig. 15 is a cross-sectional view schematically showing the structure of an epitaxially grown film including an AlN piezoelectric film 127. In manufacturing the piezoelectric film bonded substrate 200, the AlN piezoelectric film 127 as a first piezoelectric film formed on the growth substrate 21 and having a Pt film 126, an AlN film 25, and a Pt film 26, and the PZT piezoelectric film 117 formed on the growth substrate 11 and having a Pt film 116, a PZT film 15, and a Pt film 16 are peeled off from the growth substrates 21 and 11, respectively, and the AlN piezoelectric film 127 is bonded onto a Pt film 134 formed on an SOI substrate 33 that is different from both the growth substrates 21 and 11, and the PZT piezoelectric film 117 is bonded onto the AlN piezoelectric film 127.

[0037] 16 is a flowchart showing a method for manufacturing a piezoelectric film bonded substrate 200. FIGS. 17(A) and 17(B) are a top view and a cross-sectional view schematically showing the structure of a PZT epitaxially grown film in step ST201 of FIG. 16. FIGS. 17(C) and 17(D) are a top view and a cross-sectional view schematically showing the structure of a PZT epitaxially grown film in step ST202 of FIG. 16. FIGS. 18(A) and 18(B) are a top view and a cross-sectional view schematically showing the structure of an AlN epitaxially grown film in step ST204 of FIG. 16. FIGS. 18(C) and 18(D) are a top view and a cross-sectional view schematically showing the structure of an AlN epitaxially grown film in step ST105 of FIG. 16. FIGS. 19(A) and 19(B) are cross-sectional views schematically showing the holding process of a plurality of PZT piezoelectric films 117 in step ST203 of FIG. 16. Figures 20(A) and (B) are cross-sectional views schematically showing the process of holding a plurality of AlN piezoelectric films 127 in step ST206 of Figure 16. Figure 14(A) is a cross-sectional view schematically showing the process of attaching the AlN piezoelectric films 127 in step ST207 of Figure 16, and Figure 21(B) is a top view showing the state where the AlN piezoelectric films 127 have been attached. Figure 22(A) is a cross-sectional view schematically showing the process of attaching the PZT piezoelectric films 117 in step ST208 of Figure 16, and Figure 22(B) is a top view showing the state where the PZT piezoelectric films 117 have been attached.

[0038] First, as shown in Figures 17(A) and (B), a sacrificial layer 14, a Pt film 13, a PZT film 15, and a Pt film 16 are epitaxially grown on a growth substrate (step ST201), and as shown in Figures 17(C) and (D), the shapes of the Pt film 13, the PZT film 15, and the Pt film 16 are etched into a circular shape to form a plurality of PZT piezoelectric films 117 (step ST202).

[0039] 18(A) and (B), a sacrificial layer 24, a Pt film 23, an AlN film 25, and a Pt film 26 are epitaxially grown on another growth substrate (step ST204), and as shown in FIGS. 18(C) and (D), the shapes of the Pt film 23, the AlN film 25, and the Pt film 26 are etched into a circular shape to form a plurality of AlN piezoelectric films 127 (step ST205).

[0040] 19(A) and 19(B), a plurality of (four in the illustrated example) PZT piezoelectric films 117, each consisting of a Pt film 13, a PZT film 15, and a Pt film 16, are held by a stamp 42 as a holding member, and are peeled off by etching the sacrificial layer (step ST203). Also, as shown in FIGS. 20(A) and 20(B), a plurality of (four in the illustrated example) AlN piezoelectric films 127, each consisting of a Pt film 23, an AlN film 25, and a Pt film 26, are held by a stamp 41 as a holding member, and are peeled off by etching the sacrificial layer (step ST206).

[0041] 21(A) and 21(B), one of the plurality of AlN piezoelectric films 127 held by the stamp 41 is attached onto the Pt film 134 (step ST207). In the second embodiment, an example is shown in which the Pt film 134 is formed on a glass polyimide laminated substrate 133. The glass polyimide laminated substrate 133 is composed of a glass portion 131 and a polyimide portion 132 laminated thereon, and the Pt film 134 is formed on the polyimide portion 132.

[0042] 22A and 22B, one of the multiple PZT piezoelectric films 117 held by the stamp 42 is attached onto the Pt film 26 of the AlN piezoelectric film 127 attached onto the Pt film 134 (step ST208). In the first embodiment, it is desirable to add a process of performing an annealing treatment after attachment to strengthen the attachment between the Pt and the piezoelectric film, but in the second embodiment, the piezoelectric film has a structure including Pt films 16 and 26 as upper electrodes and Pt films 13 and 23 as lower electrodes, so there is no need to perform the annealing treatment.

[0043] As shown in FIGS. 21A and 21B, in the second embodiment, contact electrodes and wiring patterns are formed on a glass polyimide laminate substrate 133 using Pt, an AlN piezoelectric film 127 is attached, and then a PZT piezoelectric film 117 is attached to the Pt film 26, which is the upper electrode film. When the AlN piezoelectric films 127 held by the stamp 41 are arranged in a 2x2 matrix, they are attached to different glass polyimide laminate substrates 133 in the order of #1, #2, #3, and #4 in the figure. In this case, the AlN piezoelectric films 127 with the largest diameters are attached first. In this example, four glass polyimide laminate substrates 133 are prepared for four piezoelectric films. As shown in FIGS. 22A and 22B, the PZT piezoelectric film 117 is attached to the AlN piezoelectric film 127. The films are attached in the order of #1, #2, #3, and #4, and as shown in Figure 23(A), the PZT piezoelectric film 117 is attached on top of the AlN piezoelectric film 127, so the stamp 42, which is the holding member, can be attached without interfering with the AlN piezoelectric film 127.

[0044] Next, an insulating film 35a and a wiring film 36a are formed on the PZT film 15 and the Pt film 16, and an insulating film 35b and a wiring film 36b are formed on the AlN film 25 and the Pt film 26.

[0045] 2-3 Effects As described above, in the second embodiment, the PZT piezoelectric film 117 and the AlN piezoelectric film 127, which are difficult to epitaxially grow on the same glass polyimide laminate substrate 133, are epitaxially grown on separate growth substrates, peeled from the growth substrates, and then laminated and bonded onto a common glass polyimide laminate substrate 133, thereby making it possible to create a high-performance piezoelectric film bonded substrate 200.

[0046] Furthermore, according to the manufacturing method of the second embodiment, since no annealing treatment is required to stabilize the characteristics, it is possible to provide a plurality of piezoelectric films with different crystal structures on a non-heat-resistant substrate.

[0047] In all other respects, the second embodiment is the same as the first embodiment. [Explanation of symbols]

[0048] 100, 100a, 200 Piezoelectric film bonded substrate, 11, 21 Growth substrate (single crystal Si substrate), 15 PZT film (second piezoelectric film), 16 Pt film (second upper electrode film), 13 Pt film (second lower electrode film), 14, 24 Sacrificial layer, 17, 117 PZT piezoelectric film (second piezoelectric film), 23 Pt film (first lower electrode film), 25 AlN film (first piezoelectric film), 26 Pt film (first upper electrode film), 27, 127 AlN piezoelectric film (first piezoelectric film), 31 SiO2 part, 32 Single crystal Si part, 33 SOI substrate (substrate), 34, 134 Pt film (substrate electrode), 116 Pt film, 126 Pt film, 133 Glass polyimide laminate substrate.

Claims

1. a first piezoelectric film formed on a first substrate and having a first piezoelectric film and a first electrode film provided on the first piezoelectric film, and a second piezoelectric film formed on a second substrate and having a second piezoelectric film and a second electrode film provided on the second piezoelectric film are peeled off from the first substrate and the second substrate, respectively; the first piezoelectric film is attached onto an electrode formed on a third substrate different from both the first substrate and the second substrate; The second piezoelectric film is attached onto the first piezoelectric film.

10. A method for manufacturing a piezoelectric film-bonded substrate, comprising:

2. The second piezoelectric film comprises: a second upper electrode film formed on the second piezoelectric film; a second lower electrode film formed on a surface of the second piezoelectric film opposite to the second upper electrode film; 2. The method for manufacturing a piezoelectric film-bonded substrate according to claim 1.

3. The first piezoelectric film comprises: a first upper electrode film formed on the first piezoelectric film; a first lower electrode film formed on a surface of the first piezoelectric film opposite to the surface of the first upper electrode film; 3. The method for manufacturing a piezoelectric film-bonded substrate according to claim 1 or 2.

4. The second piezoelectric film is a single crystal, and the first piezoelectric film is a single crystal.

4. The method for manufacturing a piezoelectric film-bonded substrate according to claim 1, wherein the piezoelectric film-bonded substrate is a piezoelectric film.

5. The surface area of ​​the electrode formed on the third substrate is larger than the surface area of ​​the attachment surface of the first piezoelectric film attached to the surface of the electrode.

5. The method for manufacturing a piezoelectric film-bonded substrate according to claim 1.

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