October 2, 2012 – Sand 9, a Cambridge, MA-based developer of precision microelectromechanical systems (MEMS) timing technology for wireless and wired applications, is partnering with GlobalFoundries for high-volume manufacturing of its technology, which incorporates silicon-on-insulator (SOI) and through-silicon vias (TSV).
"Partnering with GlobalFoundries allows Sand 9 to meet heightened market demand for the highest-volume mobile applications, including handsets, tablets and other consumer electronics," stated Vince Graziani, CEO of Sand 9. "Our collaboration will ensure a stable, reliable supply chain for all of our customers in mobile as well as in wireline communications infrastructure, cellular base station, and test and measurement markets."
The deal also highlights GlobalFoundries’ MEMS design and manufacturing capabilities, pointed out Raj Kumar, SVP for the foundry’s 200mm business unit & GM of its Fab 7 facility in Singapore (formerly Chartered Semiconductor). "For Sand 9, we have established a very cost-effective and novel MEMS process technology platform integrated with polysilicon through-silicon vias (TSVs) for wafer-level packaging," he noted.
Examining a Sand 9-provided white paper (circa 2010) reveals more details about its "temperature-compensated crystal oscillator" (TCMO) technology. A silicon-based MEMS resonator is suspended and acoustically decoupled from a silicon substrate using a "special engineered substrate" (an SOI wafer), with a predefined cavity hidden in the handle silicon layer. Through-silicon vias are formed inside that SOI substrate, then the backside routing is prepared for final solder bumping. DRIE etch through the device silicon layer releases the resonator structure — having the buried cavity enables this release to be done "very fast and clean" using dry etching, the company explains, since no sacrificial layer or wet etching chemistry means one less time-consuming material removal process and it also eliminates stiction effects. The CMOS IC wafer and MEMS wafer are then bonded to create interconnects and hermetic seal around the MEMS resonator, followed by deposition of underbump metallization and solder bumps. Electrical and thermal interconnects are made during the bonding process; the TSVs are directly routed through to the IC, not the MEMS resonator.
MEMS oscillators accounted for less than 1% of the $6.3B timing devices market $6.3B in 2011, according to Semico Research, but the firm projects a sparkling ~86% compound annual growth rate (CAGR) for both MEMS oscillator sales and unit shipments over the next five years (2011-2016), mostly thanks to demand from smartphones.
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