Abstract: A filter body includes a serial arm and one or more parallel resonators in a state where they are connected in a ladder shape. The serial arm includes a plurality of serial resonators connected in series to each other. A difference of resonance frequencies among the plurality of serial resonators is smaller than a half of a difference between the resonance frequency and an antiresonance frequency of each serial resonator. The serial arm includes a first divided arm which extends from one side toward the other side in a predetermined direction on the piezoelectric substrate, and a second divided arm which is folded back from the other side of the first divided arm and extends toward the one side. The shield conductor includes a portion which is located between at least one of the serial resonators included in the first divided arm and at least one of the serial resonators included in the second divided arm.

Abstract: A filter body includes a serial arm and one or more parallel resonators in a state where they are connected in a ladder shape. The serial arm includes a plurality of serial resonators connected in series to each other. A difference of resonance frequencies among the plurality of serial resonators is smaller than a half of a difference between the resonance frequency and an antiresonance frequency of each serial resonator. The serial arm includes a first divided arm which extends from one side toward the other side in a predetermined direction on the piezoelectric substrate, and a second divided arm which is folded back from the other side of the first divided arm and extends toward the one side. The shield conductor includes a portion which is located between at least one of the serial resonators included in the first divided arm and at least one of the serial resonators included in the second divided arm.

Abstract: A surface acoustic wave element 1 includes an IDT electrode 11 having an electrode finger 11a on a piezoelectric substrate 10. The electrode finger 11a is formed by laminating an intermediate layer 12 and an electrode layer 13 having a higher coefficient of thermal expansion than that of the intermediate layer 12. The electrode finger 11a has a cross section of a trapezoidal shape that widens nearer to the piezoelectric substrate 10. An angle ?1 formed with a side surface of the intermediate layer 12 is formed larger than an angle ?1 formed with a side surface of the electrode layer 13.

Abstract: An IDT electrode (3) on a piezoelectric substrate (2) has an electrode including first metal layers (31a, 31b) formed of titanium or a titanium alloy, or chromium or a chromium alloy and second metal layers (32a, 32b) formed of aluminum or an aluminum alloy, copper or a copper alloy, or gold or a gold alloy, which are laminated alternately. The orientation degrees in the first metal layer (31a) that is closest to the surface of the piezoelectric substrate (2) in the first metal layers (31a, 31b) and the second metal layer (32a) that is closest to the surface of the piezoelectric substrate (2) in the second metal layers (32a, 32b) are higher than the orientation degrees in the upper metal layers. As compared with the prior art where the orientation degrees in the first metal layers (31a, 31b) and the second metal layers (32a, 32b) are not considered, the power handling capability of the IDT electrode (3) can be significantly improved.

Abstract: An IDT electrode (3) on a piezoelectric substrate (2) has an electrode including first metal layers (31a, 31b) formed of titanium or a titanium alloy, or chromium or a chromium alloy and second metal layers (32a, 32b) formed of aluminum or an aluminum alloy, copper or a copper alloy, or gold or a gold alloy, which are laminated alternately. The orientation degrees in the first metal layer (31a) that is closest to the surface of the piezoelectric substrate (2) in the first metal layers (31a, 31b) and the second metal layer (32a) that is closest to the surface of the piezoelectric substrate (2) in the second metal layers (32a, 32b) are higher than the orientation degrees in the upper metal layers. As compared with the prior art where the orientation degrees in the first metal layers (31a, 31b) and the second metal layers (32a, 32b) are not considered, the power handling capability of the IDT electrode (3) can be significantly improved.

Abstract: A surface acoustic wave element 1 includes an IDT electrode 11 having an electrode finger 11a on a piezoelectric substrate 10. The electrode finger 11a is formed by laminating an intermediate layer 12 and an electrode layer 13 having a higher coefficient of thermal expansion than that of the intermediate layer 12. The electrode finger 11a has a cross section of a trapezoidal shape that widens nearer to the piezoelectric substrate 10. An angle ?1 formed with a side surface of the intermediate layer 12 is formed larger than an angle ?1 formed with a side surface of the electrode layer 13.

Abstract: After electrode patterning on an electrode forming surface of a piezoelectric substrate 2 (FIG. 1(b)), a conductor layer is formed on an electrode non-forming surface of the piezoelectric substrate 2 (FIG. 1(c)). After forming the conductor layer, the conductor layer formed on the other surface is removed (FIG. 1(f)) after at least one step (FIG. 1(e)), and thereafter, dicing for separation into elements and mounting on a mounting substrate are carried out. By removing all the conductor layer on the other surface of the piezoelectric substrate, the out-of-passband attenuation and isolation performance can be significantly improved.

Abstract: In a surface acoustic wave device, an excitation electrode 5 in a surface acoustic wave element is provided on a lower surface of a piezoelectric substrate 3, and the lower surface of the piezoelectric substrate 3 is disposed in a state where it is opposed to an upper surface of a mounting base member 2. The surface acoustic wave device comprises a through hole 9 penetrating between the upper surface and a lower surface of the mounting base member 2, a lead electrode 10 closing the through hole 9 and formed so as to extend to the lower surface of the mounting base member 2, and an insulator 11 covering the lead electrode 10 so as to expose its partial area 16.

Abstract: An IDT electrode 3, and an input electrode section 5 and an output electrode section 6 each connecting with the IDT electrode 3 are formed in a filter region on one main surface of a piezoelectric substrate 2, and a semiconductor layer 22 is formed on the other main surface opposite to the one main surface of the piezoelectric substrate 2. The semiconductor layer 22 makes it possible to prevent pyroelectric destruction in the device manufacturing process as well as to prevent out-of-band attenuation characteristics from being degraded.

Abstract: A surface acoustic wave device includes an excitation electrode formed on a piezoelectric substrate and a binding electrode to be connected with a mounting substrate. The binding electrode is provided with a lower electrode formed on the piezoelectric substrate and an intermediate layer that is made of an adhesion electrode layer and a barrier metal electrode layer. The barrier metal electrode layer includes at least one impurity-containing layer. The binding electrode represents an annular electrode formed to surround the excitation electrode and a wiring electrode connected to the excitation electrode. A surface of at least one of the piezoelectric substrate, the lower electrode and the barrier metal electrode layer is bombarded to make it a rough surface. As a result, a warp due to a film stress caused in each of the layers can be suppressed.

Abstract: An IDT electrode 3, and an input electrode section 5 and an output electrode section 6 each connecting with the IDT electrode 3 are formed in a filter region on one main surface of a piezoelectric substrate 2, and a semiconductor layer 22 is formed on the other main surface opposite to the one main surface of the piezoelectric substrate 2. The semiconductor layer 22 makes it possible to prevent pyroelectric destruction in the device manufacturing process as well as to prevent out-of-band attenuation characteristics from being degraded.

Abstract: After electrode patterning on an electrode forming surface of a piezoelectric substrate 2 (FIG. 1(b)), a conductor layer is formed on an electrode non-forming surface of the piezoelectric substrate 2 (FIG. 1(c)). After forming the conductor layer, the conductor layer formed on the other surface is removed (FIG. 1(f)) after at least one step (FIG. 1(e)), and thereafter, dicing for separation into elements and mounting on a mounting substrate are carried out. By removing all the conductor layer on the other surface of the piezoelectric substrate, the out-of-passband attenuation and isolation performance can be significantly improved.

Abstract: In a surface acoustic wave device, an excitation electrode 5 in a surface acoustic wave element is provided on a lower surface of a piezoelectric substrate 3, and the lower surface of the piezoelectric substrate 3 is disposed in a state where it is opposed to an upper surface of a mounting base member 2. The surface acoustic wave device comprises a through hole 9 penetrating between the upper surface and a lower surface of the mounting base member 2, a lead electrode 10 closing the through hole 9 and formed so as to extend to the lower surface of the mounting base member 2, and an insulator 11 covering the lead electrode 10 so as to expose its partial area 16.