Gas tightness of cavities sealed by silicon wafer bonding
- 22 November 2002
- conference paper
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- No. 10846999,p. 488-493
- https://doi.org/10.1109/memsys.1997.581908
Abstract
The hermetic sealing of cavities formed by low temperature silicon direct bonding (SDB) and anodic bonding (AB) of plain and structured silicon surfaces is quantitatively investigated: Gas leakage rates along the bonding interface are determined for pressure sensor test structures by monitoring the pressure increase after a 700 h storage in a 6 bar hydrogen atmosphere. Corresponding leakage rates under atmospheric conditions as small as 10/sup -14/ (mbar 1)/s could be determined by this method. In the case of AB and of hydrophilic SDB with plain bonding surfaces, no measurable gas leakage is observed. For SDB however, only 6 nm deep grooves on one bonding surface do already cause a considerable gas leakage. For AB grooves with a depth of up to ca. 50 nm are still perfectly sealed. Here, the electrostatic pressure leads to a surface conformation through mainly elastic deformation of the bonding surfaces.Keywords
This publication has 3 references indexed in Scilit:
- Wafer bonding for silicon-on-insulator technologiesApplied Physics Letters, 1986
- Anodic bonding of imperfect surfacesJournal of Applied Physics, 1983
- Field Assisted Glass-Metal SealingJournal of Applied Physics, 1969