Poly-SiGe-Based MEMS Thin-Film Encapsulation

Author

Guo, Bin ; Wang, Bo ; Wen, Lianggong ; Helin, Philippe ; Claes, Gert ; Coster, Jeroen De ; Du Bois, Bert ; Verbist, Agnes ; Van Hoof, Rita ; Vereecke, Guy ; Haspeslagh, Luc ; Tilmans, Harrie A C ; Decoutere, Stefaan ; Osman, Haris ; Puers, Robert ; De Wol

Author_Institution

IMEC, Leuven, Belgium

Volume

21

Issue

1

fYear

2012

Firstpage

110

Lastpage

120

Abstract

This paper presents an attractive poly-SiGe thin-film packaging and MEM (microelectromechanical) platform technology for the generic integration of various packaged MEM devices above standard CMOS. Hermetic packages with sizes up to 1 mm² and different sealed-in pressures ( ~ 100 kPa and ~ 2 kPa) are demonstrated. The use of a porous cover on top of the release holes avoids deposition inside the cavity during sealing, but leads to a sealed-in pressure of approximately 100 kPa, i.e. atmospheric pressure. Vacuum ( ~ 2 kPa) sealing has been achieved by direct deposition of a sealing material on the SiGe capping layer. Packaged functional accelerometers sealed at around 100 kPa have an equivalent performance in measuring accelerations of about 1 g compared to a piezoelectric commercial reference device. Vacuum-sealed beam resonators survive a 1000 h 85°C/85%RH highly accelerated storage test and 1000 thermal cycles between -40°C and 150°C.

Keywords

CMOS integrated circuits; Ge-Si alloys; acceleration measurement; accelerometers; encapsulation; integrated circuit packaging; micromechanical resonators; microsensors; piezoelectric transducers; sealing materials; thin films; CMOS technology; MEMS thin-film encapsulation; SiGe; capping layer; hermetic packages; microelectromechanical platform technology; packaged functional accelerometers; piezoelectric commercial reference device; polythin-film packaging; pressure 100 kPa; pressure 2 kPa; sealing material direct deposition; temperature -40 degC to 150 degC; time 1000 h; vacuum sealing; vacuum-sealed beam resonators; Accelerometers; Cavity resonators; Cleaning; Electrodes; Micromechanical devices; Packaging; Silicon germanium; Hermeticity; poly-SiGe; thin-film packaging; vacuum sealing;

fLanguage

English

Journal_Title

Microelectromechanical Systems, Journal of

Publisher

ieee

ISSN

1057-7157

Type

jour

DOI

10.1109/JMEMS.2011.2170823

Filename

6070940