Future clock modules will use about 90% less power thanks to an innovative miniaturized assembly. The new development is the result of Go4Time*, an EU-wide project in which Fraunhofer IZM is also participating.

The project is striving to move miniaturized clock modules, which combine ICs (integrated circuits) with resonators in a single component, into industrial manufacture. These hybrid microsystems, whose frequencies can be adjusted as required, will be far superior to conventional quartz-based solutions as they only consume several microwatts. The clock generators will feature extremely high frequency stability and be able to compensate temperature fluctuations. This will make them suitable for a wide range of uses, including industrial applications in wireless communication systems (GSM, Bluetooth, WSN), and mass-produced consumer electronics like MP3 and DVD players.

Fraunhofer IZM is contributing its know-how in process development and manufacturing technology from wafer design to microelectronic system assembly by getting the development fit for industrial manufacture at prototype level. Fraunhofer IZM is expert in so-called through-silicon via (TSV, an metallic electrical connection passing through a silicon wafer or die) technology with extremely high aspect ratio. Using such technology, the clock modules can be stacked three dimensionally, drastically reducing the amount of build space required. Fraunhofer IZM's researchers combine this technology with wafer-thinning processes to reduce the dimensions even more. The institute is also in charge of the wafer-level packaging of the silicon-based MEMS developed within the project. The wafer-to-wafer packaging in vacuum carried out at Fraunhofer IZM is to case the hybrid resonators, which have a high Q-factor, using solder rings and thus ensure a higher processing efficiency.

* The project Go4Time - GlObal, Flexible, On demand and Resourceful Timing IC & MEMS Encapsulated System is sponsored by the European Commission as part of the 7th Framework Program (FP7) and has a project duration of three years.

The project consortium includes seven partners from five different European countries:

• Universities: Politecnico di Milano and Technische Universiteit Delft
• Research institutes: CSEM - Centre Suisse d'Electronique et de Microtechnique, VTT - Valtion Teknillinen Tutkimuskeskus and Fraunhofer IZM
• Main industry partners: Micro Crystal AG and STMicroelectronics