As innovation leader for electrical thin film testing aixACCT Systems has extended the well approved double beam technique to the first commercially available Double Beam Laser Interferometer system for up to 8 inch wafer characterization.

The Double Beam Laser Interferometer (aixDBLI) for the measurement of d33 offers a proven accuracy (x-cut quartz) up to 0.2 pm/V. The main feature of the system is the ultra fast acquisition time of a few seconds for a single measurement. Based on a new data acquisition algorithm, the measurement speed is enhanced by a factor of 100. This enables for the first time the comparison of electrical and mechanical data for thin films recorded at the same excitation frequency. Due to the the differential measurement principle the influence of sample bending is eliminated, which is the major obstacle using atomic force microscopes (AFM) for these types of measurements.

Measurements

• Electromechanical large signal strain and polarization measurements.
• Piezoelectric small signal coefficient and dielectric constant vs. dc bias voltage measurements. From these values the coupling coefficient can be derived by using the additional aixPlorer software tool if the stiffness value is known.
• Fatigue of electric and electromechanical properties.

The unique properties of the aixDBLI system make it suitable for piezoelectric and electrical reliability testing of MEMS (micro electro mechanical systems) devices on 6" wafers. The excellent resolution of this system with an repeatability accuracy better than 2 % distinguish this system for mass production qualification. The whole set-up consists of optical components in a vibration damped chamber, the TF Analyzer 2000 and some additional analog circuitry.