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.