Stability of wafer level vacuum encapsulated single-crystal silicon resonators

Author

Kaajakari, Ville ; Kiihamäki, Jyrki ; Oja, Aarne ; Seppä, Heikki ; Pietikäinen, Sami ; Kokkala, Ville ; Kuisma, Heikki

Author_Institution

VTT Inf. Technol., Finland

Volume

1

fYear

2005

Firstpage

916

Abstract

The stability of wafer level vacuum encapsulated micromechanical resonators is characterized. The resonators are etched of silicon-on-insulator (SOI) wafers using deep reactive ion etching (DRIE) and encapsulated with anodic bonding. Bulk acoustic wave (BAW) resonators show drift better than 0.1 ppm/month demonstrating that the stability requirements for a reference oscillator can be met with MEMS. The drift of flexural resonators range from 4 ppm/month to over 500 ppm/month depending on resonator anchoring. The large drift exhibited by some flexural resonator types is attributed to packaging related stresses.

Keywords

bulk acoustic wave devices; encapsulation; frequency stability; internal stresses; micromechanical resonators; silicon-on-insulator; sputter etching; wafer bonding; BAW resonator drift; DRIE; MEMS; SOI etched wafers; Si; anodic bonding; deep reactive ion etching; flexural resonator frequency drift; frequency references; frequency stability; micromechanical resonators; packaging related stresses; reference oscillator stability requirements; resonator anchoring; single-crystal silicon resonators; wafer level packaging; wafer level vacuum encapsulated resonators; Acoustic noise; Crystals; Etching; Frequency; Micromechanical devices; Oscillators; Packaging; Phase noise; Silicon on insulator technology; Stability;

fLanguage

English

Publisher

ieee

Conference_Titel

Solid-State Sensors, Actuators and Microsystems, 2005. Digest of Technical Papers. TRANSDUCERS '05. The 13th International Conference on

Print_ISBN

0-7803-8994-8

Type

conf

DOI

10.1109/SENSOR.2005.1496567

Filename

1496567