SiTime, Silicon MEMS Oscillators and Clock Generators

Silicon and Quartz Crystal Oscillator Manufacturing Flow

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Unlike Quartz Crystal Oscillators, MEMS-based Silicon Oscillators come in Cost-effective Plastic packages

All of SiTime's programmable, MEMS-based Silicon Oscillators use standard, semiconductor process equipment and can therefore use most fabrication vendors in the semiconductor eco-system. Since the MEMS-resonator is Vacuum-Sealed in Silicon, no specialized packaging is required (such as ceramic substrates or seal rings). This also facilitates use of cost-effective plastic packages that are used by most of the semiconductor industry, as well as Asian assembly houses (UTAC, Carsem, etc.) that are used by all major semiconductor vendors. SiTime follows the Fabless Semiconductor model and gains significant benefits from this flow.

Crystal Oscillators (also known as Quartz Oscillators), on the other hand, are not made from Silicon. Therefore, they require custom machinery to cut, grind, and plate the resonator. In addition, since Quartz Oscillator companies do not have analog expertise, they have to buy the Analog die from a semiconductor provider, introducing some variability in the supply chain. On the packaging front, every crystal oscillator has to be vacuum-sealed in a package. Therefore, they require specialized ceramic packages, as well as welding machines to seal these packages with a ceramic lid and a seal ring. This complex manufacturing process necessitates development of custom equipment, housed in specialized factories. If the devices are bought from outside vendors, then significant pre- and post-testing is required to ensure that these devices meet high quality levels. The inherent complexity of the manufacturing process entails a higher investment, higher manufacturing costs, longer lead times, and more quality issues.

The diagram below compares and contrasts the manufacturing flow of MEMS-based Silicon Oscillators with Crystal Oscillators and the resulting advantages of MEMS-based Silicon Oscillators.

 

 

Silicon MEMS and Quartz Crystal Oscillator Manufacturing Flow

Silicon MEMS and Crystal Oscillator Manufacturing Flow