The Influence of surface Profile on Leakage in Roomtemperature Seal-Bonding

We have developed a new calculation method of sealing quality at a bonding interface based on measured data of surface profiles and investigated influence of the surface profiles on leakage in room temperature vacuum seal-bonding. Leak rates decreased slowly as contact ratio increased, before they decreased drastically at a contact ratio close to P_c at which leak paths disappear at a bonding interface. When a contact ratio is lower than the one at which the leak rates decreased markedly, the leak rate is at least 10^-13 Pa m³/sec which is insufficient to keep inside cavity pressure vacuum for a long time. These results show that vacuum sealing needs the contact ratio which is higher than P_c.