Left-click to choose Create Recipe in the upper right-hand corner of your screen.
A window will appear with recipe options. The Create Recipe window consists of two halves
The top half of the screen has layers starting with the top layer and finishing at the base layer (substrate)
The bottom half of the screen has the parameters used to create the model for the recipe.
Select the Recipe for film thickness prediction.
Recipe: Calculates the unknown thickness by fitting within the defined range.
Simulator:In contrast, for quality control (QC) checks, the simulator compares the thickness to a single entered value rather than a range, ensuring the layer matches the specified thickness directly without fitting or adjustments.
Choose the dispersion type depends on your material: Coherent dispersion or Incoherent dispersion.
Coherent Dispersion: Refers to the wavelength-dependent variation in phase and amplitude of light as it passes through a thin film. In thin film optics, this effect occurs when the film’s thickness is comparable to the wavelength of light, accurate modeling of coherent dispersion is crucial for designing optical coatings and understanding interference patterns in thin film applications.
Incoherent Dispersion: Occurs when the thickness of a thin film is much larger than the wavelength of light, causing the light waves to lose phase coherence. This is typical for thick films or when light is not phase-sensitive.
Click the green plus to add more layers. Click the red minus to remove the current layer.
Click the down arrow to the right of the layer material to select from a list of predefined materials. To add a new material visit Add Material to Database section on how to add material to the material database.
For this example, the user has chosen a medium of air, a substrate of silicon and a coating of SiO2. Note that the medium will always be air unless the experimental setup is purged with gas or in vacuum.
Enter the estimated thickness for each layer, if known. If the thickness is unknown, leave it as -1. For the best accuracy, minimize the number of unknown layers for prediction.
If Incoherent Dispersion is selected for the Computation Type, provide a coherent layer by enabling the checkbox for that specific layer. For instance, if all layers are incoherent, leave the “Is Coherent Layer” checkbox deselected for all layers.
Next, choose the model parameters for the recipe.
Wavelength: Select or input the custom wavelength for the measurement based on the spectral range covered by the instrument being used. It is recommended to exclude the end wavelengths, as they may introduce noise into the calculation.
Light Polarization: If not using polarized light, leave in the S configuration.
Minimum Thickness: Set to or a few increments below the minimum expected thickness. All unknown layers with -1 in the Estimated Thickness column will use this minimum thickness to create the recipe.
Maximum Thickness: Set at or a few increments above the maximum expected thickness. All unknown layers with -1 in the Estimated Thickness column will use this maximum thickness to create the recipe.
Step Size: This sets the steps at which the model will calculate a predictive model for the material’s fringe patterns. More steps will increase calculation modeling time for creating the recipe. More steps will can also help with precision of the measurement.
Save As: This sets the file name and location for the recipe
Choose a name for the model being created and save.
Choose Save.
The program will rotate five dots while it creates the model. This process may take some time depending on the recipe parameters, such as the number of layers, wavelength size, minimum and maximum thickness, etc.
A message will appear stating that the model is ready. Click OK.
