Transcript Document
A Universal, High-Vacuum, Wafer-Level, MEMS Packaging Technology/Service Introductory Presentation Doug Sparks Integrated Sensing Systems Inc. (ISSYS) BAA 04-10 MX 391 Airport Industrial Dr Ypsilanti, MI 48198 USA www.mems-issys.com MEMS Vacuum Packaging Vacuum packaging is used for many MEMS devices: gyroscopes, RF-MEMS, optical displays, IR sensors, density meters, resonant clocks, Coriolis mass flow sensors, vacuum microelectronics, density meters, pressure sensors… Vacuum sealing can be accomplished at the package level (metal or ceramic packages) or at the chip/wafer level. NanoGetter Thin-Film Technology To improve the vacuum quality of ISSYS resonant sensors, reduce particle contamination and simplify the processing, a new gettering technology, called NanoGetters due to the very thin metal layers employed, was developed. Sealing Material Vacuum Cavity Micromachined Capping Wafer NanoGetter Micromachined Device Wafer- Pyrex Resonating Silicon MicroTube NanoGettersTM are covered by pending patents and US patent 6,499,354 Bond Pads A. NanoGetter and the Glass Frit Wafer Bonding Process Silicon or Pyrex Wafer B. Etch C. Sealing Material D. NanoGetters Cavity Cap Wafer NanoGetters Vacuum E. Active Micromachine Wafer Resonator or Tunneling Cantilever Bond Pad The process flow for glass frit wafer bonding, including the addition of the thin film getter used to form the chip-level vacuum package. NanoGetter Patterning & Sealing NanoGetters can be patterned using shadow masking, and various types of standard photolithography techniques. The patterning method depends on the MEMS wafer surface topography and dimensional control requirements. This thin film getter approach can be used with glass frit, eutectic, fusion / silicon direct, anodic and solder bonding Vacuum Performance – High Q Resonators Using the NanoGetter Process/Design Q-Plot Silicon Tube Resonator with NanoGetters Q=61,700 0 Gain (db) -5 Q values of 2,000-68,000 are obtained by wafer-level vacuum packaging -10 -15 -20 -25 -30 16354 16355 16356 16357 Frequency (Hz) With No Nanogetter – the average Q value is 36, standard deviation=17 16358 Program Goals & Status 7/04-7/05 • • Optimize the getter formulation and deposition process -Done Conduct reliability tests on the optimized getter - Done Standardize the design guidelines and processes for integrating the getter into the various wafer-level vacuum sealing technologies for 100mm-150mm wafer diameters – On-Going Insert the new design guidelines into MEMS Exchange – OnGoing Integrate and run getters for initial DoD customers. Q versus Time @ 95C Q • • • 33000 31000 29000 27000 25000 23000 21000 19000 17000 15000 0 500 1000 1500 Time @ 95C (hrs) 2000