Abstract: Provided is a method for manufacturing an acoustic wave device that has an excellent temperature coefficient of frequency (TCF) and high accuracy of IDT pattern forming and is capable of resisting high temperature processing of 200 degrees or more. The method for manufacturing an acoustic wave device according to the present invention includes forming an IDT (2) on a principal surface (1a) of a piezoelectric substrate (1), and forming a film by thermal spraying a material (3) having a smaller linear thermal expansion coefficient than the piezoelectric substrate onto an opposite principal surface (1b) of the piezoelectric substrate (1) where the IDT (2) is formed.

Abstract: Provided are an acoustic wave device and a method for manufacturing the same, the acoustic wave device being effectively prevented from expanding and contracting due to temperature change and having a small frequency shift. The acoustic wave device of the present invention has a piezoelectric substrate (1) having an IDT (2) formed on one principal surface of the piezoelectric substrate (1), and a thermal spray film (3) formed on an opposite principal surface (1b) of the piezoelectric substrate (1), the thermal spray film being of a material having a smaller linear thermal expansion coefficient than the piezoelectric substrate (1) and having grain boundaries and pores (4), at least a part of which is filled with a filling material (5).

Abstract: A method for manufacturing a boundary acoustic wave device prevents formation of discontinuous portions in a dielectric film without a significant decrease in the thickness of an IDT when the dielectric film is formed by deposition and without deterioration of electrical characteristics. The method includes the steps of forming an IDT on a piezoelectric substrate, forming a lower dielectric film so as to cover the IDT, conducting a planarizing step so as to smooth the rough surface of the lower dielectric film, and forming an upper dielectric film so as to cover the lower dielectric film of which the rough surface is smoothed.

Abstract: A boundary acoustic wave device includes a piezoelectric substance, a dielectric substance laminated on the piezoelectric substance, and an electrode film disposed at a boundary between the piezoelectric substance and a dielectric substance, the device utilizing a boundary acoustic wave propagating along the boundary, wherein the electrode film is any one Au alloy electrode film of an Au alloy electrode film including Cu at a ratio of about 0.01% to about 4.8% by weight, an Au alloy electrode film including Pd at a ratio of about 0.01% to about 6.8% by weight, and an Au alloy electrode film including Ni at a ratio of about 0.01% to about 3.5% by weight.

Abstract: Provided are an acoustic wave device and a method for manufacturing the same, the acoustic wave device being effectively prevented from expanding and contracting due to temperature change and having a small frequency shift. The acoustic wave device of the present invention has a piezoelectric substrate (1) having an IDT (2) formed on one principal surface of the piezoelectric substrate (1), and a thermal spray film (3) formed on an opposite principal surface (1b) of the piezoelectric substrate (1), the thermal spray film being of a material having a smaller linear thermal expansion coefficient than the piezoelectric substrate (1) and having grain boundaries and pores (4), at least a part of which is filled with a filling material (5).

Abstract: Provided is a method for manufacturing an acoustic wave device that has an excellent temperature coefficient of frequency (TCF) and high accuracy of IDT pattern forming and is capable of resisting high temperature processing of 200 degrees or more. The method for manufacturing an acoustic wave device according to the present invention includes forming an IDT (2) on a principal surface (1a) of a piezoelectric substrate (1), and forming a film by thermal spraying a material (3) having a smaller linear thermal expansion coefficient than the piezoelectric substrate onto an opposite principal surface (1b) of the piezoelectric substrate (1) where the IDT (2) is formed.

Abstract: A method for manufacturing a boundary acoustic wave device prevents formation of discontinuous portions in a dielectric film without a significant decrease in the thickness of an IDT when the dielectric film is formed by deposition and without deterioration of electrical characteristics. The method includes the steps of forming an IDT on a piezoelectric substrate, forming a lower dielectric film so as to cover the IDT, conducting a planarizing step so as to smooth the rough surface of the lower dielectric film, and forming an upper dielectric film so as to cover the lower dielectric film of which the rough surface is smoothed.

Abstract: A boundary acoustic wave device includes a piezoelectric substance, a dielectric substance laminated on the piezoelectric substance, and an electrode film disposed at a boundary between the piezoelectric substance and a dielectric substance, the device utilizing a boundary acoustic wave propagating along the boundary, wherein the electrode film is any one Au alloy electrode film of an Au alloy electrode film including Cu at a ratio of about 0.01% to about 4.8% by weight, an Au alloy electrode film including Pd at a ratio of about 0.01% to about 6.8% by weight, and an Au alloy electrode film including Ni at a ratio of about 0.01% to about 3.5% by weight.

Abstract: A boundary acoustic wave device includes a first medium, a second medium, and an IDT electrode disposed at an interface between the first medium and the second medium, the IDT electrode having an Au layer defining a main electrode layer, wherein a Ni layer is laminated so as to contact at least one surface of the Au layer, and a portion of Ni defining the Ni layer is diffused from the Ni layer side surface of the Au layer toward the inside of the Au layer.

Abstract: A boundary acoustic wave device includes a first medium, a second medium, and an IDT electrode disposed at an interface between the first medium and the second medium, the IDT electrode having an Au layer defining a main electrode layer, wherein a Ni layer is laminated so as to contact at least one surface of the Au layer, and a portion of Ni defining the Ni layer is diffused from the Ni layer side surface of the Au layer toward the inside of the Au layer.

Abstract: Methods of forming a resist pattern, of forming an electrode pattern, and of manufacturing a surface acoustic wave device are provided. The resist-pattern- and the electrode-pattern-forming methods each comprise a step of forming an antireflection film for preventing ultraviolet light from diffusely reflecting to a transparent substrate. The antireflection film is formed with a semiconductor having a band gap energy of 3.4 eV or less. The reflectance is expressed by (n1−n2)2/(n1+n2)2 is 0.15 or less, wherein n1 and n2 is the refractive indexes of the substrate and the antireflection film, respectively. The resist-pattern- and the electrode-pattern-forming methods with simple processes can achieve high-quality, reliable resist patterns and electrode patterns.

Abstract: A method of forming an electrode pattern of a surface acoustic wave device easily and reliably prevents the occurrence of an abnormality in the shape of a resist pattern. In the electrode pattern forming method, a resist layer is formed on a top surface of a piezoelectric substrate, and then exposed to ultraviolet rays through a photomask provided above the top surface of the piezoelectric substrate to form a resist pattern on the surface of the piezoelectric substrate. Furthermore, a conductor film is formed on the top surface of the piezoelectric substrate, and the resist pattern is removed by a liftoff method to form an electrode pattern of the surface acoustic wave device. Exposure is performed using ultraviolet rays having a wavelength which is completely absorbed into the piezoelectric substrate without reaching the bottom surface of the piezoelectric substrate.

Abstract: A method of forming an electrode pattern of a surface acoustic wave device easily and reliably prevents the occurrence of an abnormality in the shape of a resist pattern. In the electrode pattern forming method, a resist layer is formed on a top surface of a piezoelectric substrate, and then exposed to ultraviolet rays through a photomask provided above the top surface of the piezoelectric substrate to form a resist pattern on the surface of the piezoelectric substrate. Furthermore, a conductor film is formed on the top surface of the piezoelectric substrate, and the resist pattern is removed by a liftoff method to form an electrode pattern of the surface acoustic wave device. Exposure is performed using ultraviolet rays having a wavelength which is completely absorbed into the piezoelectric substrate without reaching the bottom surface of the piezoelectric substrate.

Abstract: A surface acoustic wave device includes a surface acoustic wave substrate having two IDT electrodes including wiring electrode portions made of aluminum disposed thereon. First, second and third metal films are laminated on each of the wiring electrode portions. The first metal film has superior bondability to aluminum, and the third metal film has superior bondability to bumps. In addition, the second metal film has an ability to suppress the diffusion of the metal defining the first metal film.

Abstract: Methods of forming a resist pattern, of forming an electrode pattern, and of manufacturing a surface acoustic wave device are provided. The resist-pattern- and the electrode-pattern-forming methods each comprise a step of forming an antireflection film for preventing ultraviolet light from diffusely reflecting to a transparent substrate. The antireflection film is formed with a semiconductor having a band gap energy of 3.4 eV or less. The reflectance is expressed by (n1−n2)2/(n1+n2)2 is 0.15 or less, wherein n1 and n2 is the refractive indexes of the substrate and the antireflection film, respectively. The resist-pattern- and the electrode-pattern-forming methods with simple processes can achieve high-quality, reliable resist patterns and electrode patterns.

Abstract: A surface acoustic wave device includes a package having an element mounting surface, a surface acoustic wave element provided in the package and having at least one bonding electrode, an adhesive arranged such that the surface acoustic wave element is fixed to the element mounting surface of the package, and at least one bonding wire connected to the at least one bonding electrode. The at least one bonding electrode has at least one line-shaped through hole extending therethrough at a region where the at least one bonding wire is connected to the at least one bonding electrode.

Abstract: A surface acoustic wave device includes a surface acoustic wave substrate having two IDT electrodes including wiring electrode portions made of aluminum disposed thereon. First, second and third metal films are laminated on each of the wiring electrode portions. The first metal film has superior bondability to aluminum, and the third metal film has superior bondability to bumps. In addition, the second metal film has an ability to suppress the diffusion of the metal defining the first metal film.