Surface acoustic wave device and production method thereof and mobile communication equipment using it

Abstract

The invention relates to the elastic surface acoustic wave device and production method thereof and mobile communication equipment using it. An electrode material for a elastic surface acoustic wave device comprising laminates in at least two stages, each laminate being formed by laminating a second metal layer (5) on a first metal layer (4), wherein the first metal layer (4) uses a metal having a diffusion coefficient to Al which is smaller than a self-diffusion coefficient of Al, and the second metal layer (5) uses a ternary or higher Al alloy in which at least two kinds of metals, at least one kind of metal solid-dissolved to Al at room temperature and at least one kind of metal which segregates in an Al grain boundary or forms an intermetallic compound with Al at room temperature are added, whereby a surface acoustic wave device excellent in power resistance, capable of using a conventional pattern forming technique, being thermally stable and preventing an insertion loss increase can be provided.

Description

technical field [0001] The present invention relates to a surface acoustic wave device with excellent electrical power resistance performance, in particular to a surface acoustic wave device with improved power withstand by electrodes, a manufacturing method thereof, and a mobile communication device using the device. Background technique [0002] In recent years, with the high frequency of mobile communication. The operating frequency of surface acoustic wave devices (hereinafter referred to as SAW devices: surface acoustic wave devices) is also developing towards higher frequencies ranging from hundreds of MHz to several GHz. In addition, due to the need to withstand relatively large power, studies have been conducted on the use of SAW devices in the filter portion of antenna duplexers using large dielectric filters in order to meet the demand for miniaturization of terminal equipment. Moreover, with the increase of operating frequency and operating power, the stress on t...

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Problems solved by technology

[0008] However, since this structure adopts the lamination of Al and the second film made of a metal whose diffusion coefficient to aluminum is larger than that of aluminum, in the heating process after film formation, the Al and the second film Diffusion and alloying reactions between the metals, there is a problem that the specific resistance of the electrode increases due to this

The increase in the specific resistance of the electrode has a great influence on the insertion loss of the SAW device, and it is particularly problematic when manufacturing a transmit-side filter of an antenna duplexer that requires low loss.

[0009] In addition, as the frequency becomes higher and higher, the line width of the IDT electrode becomes thinner, and the temperature of the chip increases during operation of the SAW device to which a large power is applied, so the electrical characteristics of the SAW device also have stability problems.

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