论文信息 - Room temperature vacuum sealing using surfaced activated bonding with Au thin films [microresonator example]

Room temperature vacuum sealing using surfaced activated bonding with Au thin films [microresonator example]

We report surface activated bonding (SAB) using Au thin films with a thickness of a few tens of nanometers which can be applied to room temperature vacuum sealing for microelectromechanical systems (MEMS) packaging. In a previous study, it was found that room temperature bonding of Si/Si and Si/chemical mechanical polished (CMP) electroplated Cu could be successfully applied to vacuum sealing of micro cavities. However this method needs high vacuum in bonding process for keeping activated surfaces and the surfaces should be cleaned by wet processes. In this study, we attempt to realize room temperature vacuum sealing in low vacuum without any wet surface pre-treatments utilizing Au thin films with controlled surface roughness. We propose and develop packaging structures with comb-drive resonators for characterization of sealing quality and show the applicability of SAB of Au-Au thin films to vacuum-seal packaging.

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

[2] Tadatomo Suga,et al. Surface Activated Bonding-An Approach to Joining at Room Temperature , 1993 .

[3] H. Okada,et al. Room temperature vacuum sealing using surface activated bonding method , 2003, TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664).

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

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

[6] Tadatomo Suga,et al. Feasibility of surface activated bonding for ultra-fine pitch interconnection-a new concept of bump-less direct bonding for system level packaging , 2000, 2000 Proceedings. 50th Electronic Components and Technology Conference (Cat. No.00CH37070).

[7] K. Ikeda,et al. Vacuum-sealed silicon micromachined pressure sensors , 1998, Proc. IEEE.

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

[9] Tadatomo Suga,et al. Room-temperature interconnection of electroplated Au microbump by means of surface activated bonding method , 2001, 2001 Proceedings. 51st Electronic Components and Technology Conference (Cat. No.01CH37220).