An entirely new technology that is expected to drastically cut the costs of Micro Electro Mechanical Systems (MEMS) has been pioneered by Spanish company, Baolab Systems. Key to this breakthrough technology is the way in which the company can construct nanoscale MEMS within the actual structure of a CMOS wafer using standard, high volume CMOS lines, which is both a rapid and easily controlled process.
Using a standard CMOS line is where the big product costs savings are made and the company is predicting that the savings could be as high as 65% over traditional MEMS manufacturing methods.
The Baolab NanoEMS technology uses the existing metal layers in a CMOS wafer to form the MEMS structure via standard mask techniques. The Inter Metal Dielectric (IMD) is then etched away through the pad openings in the passivation layer using vHF (vapour HF). The etching uses equipment that is already available for volume production and takes less than an hour, which the company says is insignificant compared to the overall production time. The holes are then sealed and the chip packaged as required. As standard CMOS processes are used, NanoEMS MEMS can be directly integrated with active circuitry to suit specific applications.
Baolab has successfully created these MEMS devices using standard 0.18µm 8in. volume CMOS wafers with four or more metal layers, and has achieved minimum feature sizes down to 200nm. This is an order of magnitude smaller than is currently possible with conventional MEMS devices, bringing the new NanoEMS MEMS into the realm of nanostructures, with the subsequent benefits of smaller sizes, lower power consumption and faster devices.
Baolab plans to make a range of discrete MEMS including RF switches, electronic compasses and accelerometers, along with solutions that combine several functions on one chip. The prototype stage has already demonstrated that NanoEMS technology and evaluation samples will be available later this year. These are aimed at handset designers and manufacturers and power amplifier and RF front-end module markets.
In mobile phone applications, NanoEMSTM have multiple uses, from higher performance, lower cost replacements for GaAs FETs for RF switching applications, to enabling tunable active RF components such as power amplifiers and low noise amplifiers. This tunable capability is expected to change the RF section of mobile devices by significantly reducing the number of components needed in a mobile phone. NanoEMSTM are also being developed for sensors in the mobile phone, such as electronic compasses, accelerometers, and several other functions in a single chip.