Spectral analysis with visible and near-infrared (NIR) wavelengths has been used for decades to measure the thickness of coatings on silicon wafers for the electronics industry, using devices that typically cost over $100,000. Filmetrics Inc. in San Diego makes a variation, called a Spectral Reflectance Thickness Gauge, that costs about $10,000. It’s used mostly off-line to measure thin films, multilayered barrier films, and coatings; but in the last five years processors have begun to install it on-line as well. Filmetrics has sold about 20 systems for online use, typically with a single instrument mounted in the middle of a web where the film or a layer or coating is too thin to be measured with capacitance or beta gauges. Filmetrics NIR gauges measure a 1.5-mm spot of film as thin as 0.05 micron and distinguish individual layer thicknesses by means of the different refractive indices of the materials. These gauges can measure both clear films and ones containing large amounts of TiO2 or carbon black. (585) 223-8534 • www.filmetrics.com
9335 Chesapeake Dr. San Diego, CA 92123
Phone (858) 573-9300 Fax (858) 573-9400
Editor PickSizing the Barrier Gap
Here’s a less complex way to properly size the barrier gap for barrier screws.