ULVAC Introduces the UNECS-2000, UNECS-3000A spectroscopic ellipsometer

The compact UNECS-2000 spectroscopic ellipsometer eliminates the need for conventional methods that mechanically or electrically control polarization devices. It takes advantage of the spectrums obtained from the polarization interference occurring between two high-order phase shifters to instantaneously capture the wavelength distribution of the sample's spectroscopic polarization parameters. The emitter and sensor heads are small with built-in light source and controller. It comes with the computer control and analysis software. The motor stage can handle samples up to 200 mm in diameter. Using parallel measurement, the thickness of up to six individual film layers are measurable at the same time.

ULVAC Technologies has also recently introduced the UNECS-3000A automated high-speed spectroscopic ellipsometer. It combines the ultra-fast measuring capabilities of UNECS-2000 high-speed spectroscopic ellipsometer with an automated mapping function that can handle 300 mm substrates. The UNECS-3000A takes just 120 seconds to measure 106 points on a φ300 mm wafer, less than one fifth time for conventional measuring instruments. It can be used for evaluating resist film thickness for semiconductor lithography and organic EL display film, and in a wide range of applications including on production lines and in research and development.

Ellipsometry Background

Ellipsometers measure the film thicknesses and refractive indexes of transparent or semi-transparent thin films with excellent precision, without coming into contact with them. These measuring instruments are used in many industries including the semiconductor and liquid crystal display industries. Ellipsometers are broadly classified into the single wavelength type, whose light sources are lasers, and the spectroscopic type, which uses halogen, xenon, or other lamps. Spectroscopic ellipsometers can analyze multi-layer films or other complexly structured thin films because they can measure the polarized light condition of thin films in certain wavelength bands. There are two categories of measurement methods: the optical device rotation method and the phase modulation method. The former method controls the polarization properties by mechanically rotating optical devices. The latter method controls the polarization properties of the polarization device electrically. These methods require either mechanical or electrical control of complex optical systems. This is why developing more compact and faster ellipsometers has been difficult.