Spectroscopic Reflectometry

Nanometrics pioneered the use of micro-spot spectroscopic reflectometry for semiconductor film metrology. Spectroscopic reflectometry uses multiple wavelengths (colors) of light to obtain an array of data for analysis of film thickness and other film parameters. Today's semiconductor manufacturers still depend on spectroscopic reflectometry for most film metrology applications. Reflectometry is the measurement of reflected light. For film metrology, a wavelength spectrum in the visible region is commonly used. Light reflected from the surfaces of the film and the substrate is analyzed using computers and measurement algorithms. The analysis yields thickness information and other parameters without contacting or destroying the film.

Nanometrics was the first to use a DUV reflectometer for material analysis. This patented technology was initially used for the determination of absolute reflectance in the ultraviolet region. Deep UV reflectometry technology also provides enhanced measurement performance for thinner films and multi-layer film stacks.

Spectroscopic Ellipsometry

Like reflectometry, ellipsometry is a non-contact and non-destructive technique used to analyze and measure films. An ellipsometer analyzes the change in a polarized beam of light after reflection from a film's surface and interface. The systems are spectroscopic, providing ellipsometric data at many different wavelengths. Spectroscopic ellipsometry provides a wealth of information about a film, yielding very accurate and reliable measurements. In general, ellipsometers are used for thin films and complex film stacks, whereas reflectometers are used for thicker films and stacks.