Polyimide as an acoustic absorber for high frequency SAW applications

Author

Johnsen, C.A. ; Bagwell, T.L. ; Henderson, J.L. ; Bray, R.C.

Author_Institution

Hewlett-Packard Co., Santa Rosa, CA, USA

fYear

1988

fDate

2-5 Oct 1988

Firstpage

279

Abstract

A novel method is described for damping unwanted acoustic energy in high-frequency SAW (surface acoustic wave) devices through the use of a polyimide layer which is patternable with high resolution on the surface of the device. The polyimide layer maintains its absorptive acoustic properties after a high-temperature bakeout at 300°C and exhibits excellent reliability. The application process and process tolerances are described. Experimental results for the acoustic attenuation factor are presented as a function of SAW frequency. The attenuation of 3.0-3.5-μm-thick polyimide films for SAWs on LiNbO₂ was measured to be in the range of 10-20 dB/100 μm at frequencies in the range of 300 MHz to 500 MHz

Keywords

acoustic wave absorption; surface acoustic wave devices; 3.0 to 3.5 micron; 300 degC; 300 to 500 MHz; LiNbO₂; SAW devices; SAW frequency; acoustic absorber; acoustic attenuation factor; acoustic energy damping; application process; high frequency SAW applications; high-temperature bakeout; polyimide layer; process tolerances; reliability; Acoustic devices; Acoustic waves; Attenuation; Damping; Energy resolution; Frequency; Maintenance; Polyimides; Surface acoustic wave devices; Surface acoustic waves;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 1988. Proceedings., IEEE 1988

Conference_Location

Chicago, IL

Type

conf

DOI

10.1109/ULTSYM.1988.49383

Filename

49383