The FS‑1 software uses a web-browser based user interface, and does not require any software installation on the controlling computer. Any desktop, laptop, tablet, or even smart phone that runs a modern web browser can be used to control and operate the FS‑1 Multi-Wavelength Ellipsometer. Computers can be directly connected to the FS‑1 by a standard Ethernet cable, or by connecting the FS‑1 to a wireless router, devices can access the FS‑1 via WiFi. The FS‑1 software provides easy to use Modes for performing single, continuous, and dynamic measurements, calibrating and testing the sensor, and building and testing data analysis models.
To determine sample properties of interest (such as layer thicknesses, optical constants, etc.), it is necessary to analyze the measured ellipsometric data. The FS‑1 software implements the traditional model-based, least squares analysis approach, encapsulating and hiding all the necessary thin film optics calculations and non-linear regression algorithm behind an easy to use interface. Models are built by simply selecting materials for the substrate and layer(s), and defining model fit parameters (such as layer thicknesses, angle of incidence of the measurement beam, index of refraction, etc.). Clicking the “Fit Data” button invokes the regression algorithm, which automatically adjusts the model fit parameters to minimize the difference between the model calculated and measured ellipsometric data, resulting in the “best fit” values for the fit parameters. To improve the convergence of the model fit, minimum and maximum bounds can be specified for the fit parameters, and to achieve global convergence with wide parameter bounds, starting increments for parameters can also be specified. The Model ValidatorTM button automatically tests the model to verify convergence, and estimates the precision in the sample fit parameters for a typical FS‑1 measurement.
The FS‑1 software also provides advanced features, such as Trajectory Analysis for determining a consistent set of optical constants for ellipsometric data acquired on a series of samples with a range of film thicknesses (as is often the case when performing in situ ellipsometry measurements during the film deposition process). A Film Sense Application Programming Interface (FS‑API) is also available, to support the integration of the FS‑1 Thin Film Sensor with process control computers and PLC’s, and to enable the creation of customized data acquisition software.