Multi-scan Experimental Data (BBM data)

Measurement data obtained in-situ can be easily imported and loaded to OptiLayer using Multi-Scan Measurements Manager available in OptiRE through Data –> Multi-scan measurements.

In the lower part of the window Measurements database is displayed. The upper part displays layers of the design currently loaded to memory (see below).

Load button loads selected measurement data file to the position selected by an arrow in the design. This position correspond to measurements performed after the deposition of the selected layer. Alternatively you may use Layer column in order to assign a layer to a measurement data file.

Unload button removes measurement data from the selected position in the upper part of the window.

MultiLoad… button invokes a special three-step dialog allowing to perform massive and automated multi-scan measurement assignments.

Unload button allows you to unload selected measurement file from memory. It is also possible to unload all measurements from memory at once using popup menu invoked after clicking a small arrow at the right part of the button.

Reload button allows you to load measurement file from the database again discarding all possible in-memory modifications, for example, results of measurements preprocessing.

Example: loading multi-scan data that is already in the OptiLayer database.

View –> Scan Discrepancies,

you can plot discrepancies between theoretical (or model) spectral characteristic and corresponding measurement scan.

Example: Comparison theoretical and measurement transmittance data related to a 15-layer beamsplitter. The data corresponding to the 3rd, 8th, 12th, and 15th recorded scans are shown below. The scan discrepancies are represented on the right panel.

\[ D_j=\frac 1L\sum\limits_{i=1}^L \left(T(d_1,…,d_j;\lambda_i)-\hat{T}(\lambda_i)\right)^2, \]

where \(\lambda_1,…,\lambda_L\) are measurement spectral points, \(\hat{T}(\lambda_i)\) are measurement values.

The scan discrepancies are represented as a diagram (see below) or in a numerical form in Spreadsheet tab.

Recent version of OptiLayer allows you to analyze BBM movies.

Example: a special 15-th layer quarter wave mirrors was produced and two errors (+5% and -7%) in layers 3 and 12, respectively, were imposed. Layer materials – Ta2O5, SiO2; Glass substrate, central wavelength – 600 nm. Deposition technique – magnetron sputtering. Thickness control – well-calibrated time-monitoring. In the course of the deposition process, transmittance data scan were recorded insitu after each layer. The experimental data are compared with the theoretical ones below (left panel). A model with random errors was applied, i.e. the diecrepancy function \(DF\) was minimized with respect to relative errors in layers thicknesses \(\delta_1,…,\delta_{15}\):

\[ DF^2=\frac 1M\frac 1L\sum\limits_{i=1}^M\sum\limits_{j=1}^L\left(T(d_1(1+\delta_1),…,d_m(1+\delta_m))-\hat{T}(\lambda_j)\right)^2 \]

Initial fitting of in situ measurements recorded after each layer by theoretical transmittance of 15-layer quarter wave mirror.

Achieved fitting of in situ measurements recorded after each layer by model transmittance of 15-layer quarter wave mirror.

Estimated relative errors in layer thicknesses. Two errors in layers number 3 and 12 are reproduced with high accuracy.