Baolab NanoEMS constructs MEMS within CMOS wafer

This is said to be easier and quicker with fewer process steps than existing MEMS fabrication techniques, which build the MEMS on the surface of the wafer.

Baolab Microsystems said this reduces the costs of a MEMS by up to two-thirds and even more if several different MEMS are created together on the same chip.

The Baolab NanoEMS technology uses the existing metal layers in a CMOS wafer to form the MEMS structure using 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.

The holes are then sealed and the chip packaged as required.

As only standard CMOS processes are used, NanoEMS MEMS can be directly integrated with active circuitry as required.

Baolab has created MEMS devices using standard 0.18um 8in volume CMOS wafers with four or more metal layers, and has achieved minimum feature sizes down to 200nm.

Baolab will be making a range of discrete MEMS including RF switches, electronic compasses and accelerometers, along with solutions that combine several functions in one chip.

The prototype stage has already proved the 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.