Necessary load for room temperature vacuum sealing

This paper presents the effects of bonding load and surface roughness on room temperature vacuum sealing carried out using the surface-activated bonding (SAB) method. Vacuum sealing is necessary to achieve highly reliable packaging and for the functioning of devices such as infrared sensors, resonance sensors and resonant micromirrors. If the vacuum seal bonding is carried out at room temperature, then it can be applied to diverse combinations of materials. In the previous experiments, we found that room temperature bonding of Si/Si and Si/Cu using SAB could be successfully applied to vacuum sealing of microcavities. In order to design sealing structures and estimate suitable bonding conditions, simple models for vacuum sealing are considered. Based on the percolation theory, we have concluded that for vacuum sealing, the degree of contact between seal surfaces is greater than 0.6. Further, we introduce a model to provide a criterion for vacuum sealing applied to smooth metal surfaces with plastic deformation using average clearance. We then discuss the necessary load and surface roughness for room temperature vacuum sealing applied to metal film surfaces.

[1]  Henri V. Jansen,et al.  Self-aligned 0-level sealing of MEMS devices by a two layer thin film reflow process , 2003, Symposium on Design, Test, Integration and Packaging of MEMS/MOEMS 2003..

[2]  Tadatomo Suga,et al.  Room temperature Cu–Cu direct bonding using surface activated bonding method , 2003 .

[3]  S. Weichel,et al.  Strength and Leak Testing of Plasma Activated Bonded Interfaces , 2002 .

[4]  Stefan Bengtsson,et al.  Plasma assisted room temperature bonding for MST , 2001 .

[5]  P. Rai-Choudhury,et al.  MEMS and MOEMS Technology and Applications , 2000 .

[6]  Liwei Lin.  MEMS post-packaging by localized heating and bonding , 2000 .

[7]  E. Beyne,et al.  The indent reflow sealing (IRS) technique-a method for the fabrication of sealed cavities for MEMS devices , 2000, Journal of Microelectromechanical Systems.

[8]  Q.-Y. Tong,et al.  Wafer Bonding and Layer Splitting for Microsystems , 1999 .

[9]  T. Suga,et al.  Effect of Surface Roughness on Room-Temperature Wafer Bonding by Ar Beam Surface Activation , 1998 .

[10]  R. Wolffenbuttel,et al.  Vacuum sealing of microcavities using metal evaporation , 1997 .

[11]  U. Gösele,et al.  Gas development at the interface of directly bonded silicon wafers: investigation on silicon-based pressure sensors , 1996 .

[12]  M. Kimura,et al.  A highly sensitive thermistor bolometer for a clinical tympanic thermometer , 1996 .

[13]  M. Esashi,et al.  Vacuum packaging for microsensors by glass-silicon anodic bonding , 1994 .

[14]  G. Kissinger,et al.  Void-free silicon-wafer-bond strengthening in the 200–400 °C range , 1993 .

[15]  J. Greenwood.  Silicon in mechanical sensors , 1988 .

[16]  N. Amer,et al.  Novel optical approach to atomic force microscopy , 1988 .

[17]  P. Couturier.  Japan , 1988, The Lancet.

[18]  C. Lobb,et al.  Percolation in two-dimensional conductor-insulator networks with controllable anisotropy , 1979 .

[19]  J. Williamson,et al.  On the plastic contact of rough surfaces , 1972, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.

[20]  K. Johnson.  Contact Mechanics: Rough surfaces , 1985 .

[21]  Y. Kimura.  Estimation of the number and the mean area of real contact points on the basis of surface profiles , 1970 .