Technical Issues - Workbook Tutorial I - Getting Started

The FilmStar Workbook provides capabilities not readily achieved otherwise. Consider yield estimation for a multi-angle coating specification that includes average, min/max and ripple. The Workbook makes such analyses easy. Another example is optimization in which layers are restricted to given ratios and thicknesses.

Ready to go beyond Getting Started?
Additional topics: Multiple Spectra, Constraints (optimization)

The FilmStar Workbook is an Excel-compatible (Excel not required) spreadsheet supporting two file formats: *.vts (native) and *.xls (Excel 5.0/95). The Workbook is activated (DESIGN, MEASURE) via Tools.. Workbook <F3> or by clicking the Workbook icon. The MEASURE (Scantraq) Workbook is similar but lacks Setup, Design and Optimize menus.

In this page we introduce basic Workbook concepts and illustrate tolerancing and optimization. To begin, activate the Workbook and click File.. New to arrive at the following. Add some formulas just as in Excel.

Workbook functions connect to FilmStar via defined names. A defined name labels a cell or a group of cells. FilmStar assigns special meanings to the following eight names:
  • DataMarker - Data upper left
  • DataType - Details about the data
  • Passed -TRUE or FALSE
  • Macro - Commands to be executed

    DESIGN only:
  • Design - Thin film design
  • Objective - Optimization merit function
  • Constraint - Optimization constraint(s)
  • Yield - Tolerancing % Passed=TRUE

See FilmStar Help (DESIGN Reference.. FilmStar Workbook.. Defined Names) for details. Note that special defined names are automatically indicated with yellow background. You add a defined name with Edit.. Define Name <F6>.

Close the Workbook and open FILM Archive BBAR. Click Setup.. Graph Axes <Ctrl+G> and verify that calculation range is 450-750 x10 (Inverse wavelength spacing unchecked). Click the Calculate button to evaluate the spectrum. Re-save BBAR.faw with the new range.

Activate the Workbook and open c:\Winfilm\Workbook\QCBBAR.xls. There are three defined names: DataType ($B$1), DataMarker ($A$3) and Passed ($E$8). DataType=1 gives R/T in the range 0-100% rather than 0-1. Cell Passed {AND($E$5<=0.5,$E$6<=1)} is TRUE when average %R is <= 0.5% and maximum %R is <=1.0%. DataMarker merely indicates the location of spectral data. Note the use of AVERAGE ($E$4) and MAX ($E$5) functions. Can't see these functions? Click <F7> to open the edit bar or <Shift+F7> to display all functions. Note how much easier it is to compute average and maximum with spreadsheet functions than with BASIC code.

In normal operation spectral data is automatically pasted when the Workbook is activated by clicking on it. As will be demonstrated later, the action can be defeated when necessary. At this time we suggest that you reproduce the steps illustrated in the Flash video below. Comment: there is no particular reason why cell $A$1 has a cyan background. You might like to use colors to highlight labels, but never use yellow!

With the optimized design loaded, activate the Workbook and click Evaluate.. Tolerancing.. Values <Ctrl+N>. Enter 3.0% and 100 Iterations as shown. Click Evaluate.. Tolerancing.. Run <Shift+Ctrl+F9>.

At the conclusion note that % yield is displayed in the main window status bar. This is not entirely satisfactory because the value can be erased by moving the mouse. As an alternative add defined name Yield to cell $E$10 and repeat the calculation.

Returning to the main DESIGN window, reload the original (unoptimized) BBAR file (design .1H .1L .5H .25L) checking that the graph range is 450-750 x 10 nm. Calculate the spectrum to verify and re-activate the Workbook. Add defined name Objective to cell $E$5 {AVERAGE($B$4:$B$34)}. An objective (aka merit function) is a quantity to be minimized. Click Optimize.. Optimize <Ctrl+O> in the Workbook window to minimize average reflectance. Finally, click on the main DESIGN window and recalculate the spectrum.

Why optimize in the Workbook rather than the main DESIGN window? In this case there is no reason; we would do as well with the usual optimization targets. Here we are merely showing how things work. The advantages of Workbook optimization will become evident in subsequent Workbook Tutorial pages.

Before leaving this page, return to QCBBAR.xls and set DataType=3. Now go back and forth between the main DESIGN window and the Workbook. Notice how spectra are transferred to multiple columns. You have just activated looping, the subject of the next Workbook tutorial.