A versatile timing microsystem based on wafer-level packaged XTAL/BAW resonators with sub-µW RTC mode and programmable HF clocks

Over recent years the several decades long quartz-dominated timing industry has been continuously challenged by the introduction of new products or demonstration of prototypes based on MEMS resonators [1-4]. The poor intrinsic stability of such devices has led to the development of very high performance temperature sensors to reach TCXO-level frequency stability [5]. One of the true advantages of the technology is the fact that well-proven semiconductor manufacturing technologies amenable for high volume production can be leveraged to produce wafer-level encapsulated low-cost components. This paper explores how XTAL resonators could benefit from similar wafer level, vacuum sealing packaging technologies with the demonstration of a generic versatile timing module.

[1]  Fred S. Lee,et al.  A temperature-to-digital converter for a MEMS-based programmable oscillator with better than ±0.5ppm frequency stability , 2012, 2012 IEEE International Solid-State Circuits Conference.

[2]  R. Ruby,et al.  Wafer-scale packaging for FBAR-based oscillators , 2011, 2011 Joint Conference of the IEEE International Frequency Control and the European Frequency and Time Forum (FCS) Proceedings.

[3]  D. Ruffieux,et al.  Hermetic wafer level packaging of MEMS components using through silicon via and wafer to wafer bonding technologies , 2013, 2013 IEEE 63rd Electronic Components and Technology Conference.

[4]  François Krummenacher,et al.  Silicon-resonator-based, 3µA real-time clock with ±5ppm frequency accuracy , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.