Surface acoustic wave device and method of manufacturing the same, IC card, and mobile electronic apparatus

Abstract

A SAW device 1 includes: a SAW chip 2 having IDT electrodes 5 disposed on a piezoelectric substrate 4, extraction electrodes 8 extracted from the IDT electrodes, and a metal bonding portion 9 disposed along the entire periphery of the piezoelectric substrate; and a cover 3 having through-holes 11 disposed on a glass substrate 10 at positions corresponding to the extraction electrodes 8, a metal bonding portion 13 disposed along the entire periphery of a lower surface of the glass substrate, and connection electrodes 12 disposed along circumferences of openings of the through-holes. The metal bonding portion of the SAW chip, he metal bonding portion of the cover and the connection electrodes are bonded, respectively by thermal press-welding, and the IDT electrodes are hermetically sealed within a space defined between the SAW chip and the cover. The external electrodes 15 on an upper surface of the glass substrate and the IDT electrodes are electrically connected to each other through metal films 14 formed in the through-holes and a sealing material 16. On the upper surface of the cover, recessed portions 18 are formed at position overlapping the external electrodes.

Description

technical field [0001] The present invention relates to SAW devices such as resonators, filters, and oscillators utilizing surface acoustic waves (Surface Acoustic Wave: SAW), and methods for manufacturing the same. Furthermore, the present invention relates to an IC card and a portable electronic device including the SAW device. Background technique [0002] Conventionally, SAW devices such as resonators, filters, and oscillators using SAW elements having IDTs (comb-like electrodes) formed on the surface of a piezoelectric substrate are widely used in various electronic devices. transducer) and reflectors, and utilizes surface acoustic waves excited by the IDT. In particular, recently, in addition to high frequency and high precision of SAW devices corresponding to high-speed information communication, further thinning is required for use in small / thin information equipment such as IC cards. [0003] In conventional SAW devices, the SAW element is generally hermetically s...

AI Technical Summary

Problems solved by technology

However, it is actually difficult to reliably hermetically seal the gap between the opening inside the through-hole and the lead-out electrode using an electrode film obtained by sputtering.

[0014] In addition, the SAW device of the two-layer structure is a surface-mount type, and the external electrodes formed on the surface of the cover substrate are directly bonded to the surface of the printed circuit board or the like using solder, adhesive, etc. However, the smaller the size, the smaller the mounting area. smaller

Therefore, it becomes difficult to mount the SAW device in a good state, or to obtain sufficient adhesive strength after mounting, and there is a concern that sufficient mechanical strength cannot be secured against external forces such as deflection.

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