Ultrareproducible SAW Resonator Production,
Abstract
A fabrication process for 300 MHz and 461 MHz SAW resonators with unloaded Q factors of 15000 and 12000 has been developed which yields a frequency reproducibility of + or - 15 ppm within one substrate without individual frequency trimming for each chip. This was achieved by (1) x-ray topographical preselection of natural-grown quartz substrates, (2) by the use of metallic grating reflectors fabricated by direct step on the water with a 1:10 optical projection printing and lift-off technique, and (3) by careful mounting. With typically 68 chips per substrate, 90% yield has been regularly achieved. The frequency deviation from substrate to substrate for selected natural quartz material is about + or - 20 ppm. Therefore for most applications the post fabrication frequency adjustment (trimming) of each individual resonator can now be omitted. The measurement of accelerated (high temperature) aging indicates that aging rates are obtained which are comparable to those for precision bulk wave crystals.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1982
- Accession Number
- ADP001554
Entities
People
- E. Willibald
- W. E. Bulst