Introduction to TFCompanion

© 2004 Semiconsoft, Inc.

TFCompanion ver. 3.0

What’s in Tutorial

1. Brief overview of GUI

2. Calculating filmstack parameters

3. Data simulation and sensitivity analysis

4. Error estimation analysis

5. New options in ver. 3.0rc

6. New feature build 12/21/2004

TFCompanion is a multi-threaded application – this means that

there maybe several windows open and accessible at the same time.

To toggle between different windows – use OS specific keyboard short-cuts:

For MS Windows and Linux (KDE 2)—ALT+Tab

For Linux (Gnome) –CTRL+ALT+[Fn] (F1-F8)

For MAC OS X – check “man screen” for details

Other OS – use OS specific keyboard shortcuts

Brief GUI overview

Calculating Filmstack parameters

Data simulation

Error estimation

Brief GUI overview

• Functionality and information is concentrated in the main screen

• Other data and functionality is accessed using main menu or Toolbar buttons

• GUI configuration and options depends on user profile

• Next slide shows main screen (user:Administrator)

Brief GUI overview (cont.)

We will review details of the GUI using

several examples:

• Calculation

• Simulation

• Error estimation

Brief GUI overview

Calculating Filmstack parameters

Data simulation

Error estimation

Calculation

Calculation include 4 steps:

1. Load measured data (from DB or file)

2. Create & Load filmstack model (please review Filmstack tutorial for details)

3. Select calculated parameters

4. Calculate and review the results

Calculation-Loading data

TFCompanion supports data import from file in most popular formats:

• Beaglehole Instruments• Sopra• Woollam• JY• Rudolph Technologies

Format is recognized automatically.

Calculation –Loading data

File contains two measured spectra –

may select one spectra or both

Calculation- selecting parameters

• We have loaded filmstack model – now need to select calculated parameters

• We are using 150A SiON/Si filmstack

• SiON dispersion is represented using Tauc-Lorentz approximation

Calculation- selecting parameters

• We are interested in Thickness and n,k @248 nm

• Directly calculated parameters are Tauc-Lorentz approximation coefficients – not n,k

• n,k @ 248nm – they will be displayed parameters we will be prompted to select TL coefficient to calculate (but not display)

Calculation- selecting parametersWe are prompted to select TL coefficients for calculation – we will select them by clicking on records

Calculation

• We have selected parameters and are ready for calculation.We have two options:

– Selecting Calculate button starts calculation directly

– Selecting Calculate from toolbar or menu starts Calculation dialog and gives more control

We select Calculate button.

Calculation

• We will now try another option – select calculation from the ToolBar

• We will do the same calculation but in the Calculation dialog and will “cache” (save the results)

• Please review Calculation tutorial for more details

Calculation-Review results

• We have cached results (saved to memory). Note that the cache can be saved as a part of the “project” and loaded during next session

• Now we will close Calculation dialog and start Compare Data center from the main menu.

Compare Data Center is now displayed

Note. You may need to use ALT-Tab to toggle between main screen and Compare data Center

Calculation- review results

• We can now print or save plot to a file (using menu options in the plot dialog)

Please review Compare data tutorial for more details

• After closing this dialog we return to the main menu

• Now we will review the SiON layer detail

Brief GUI overview

Calculating Filmstack parameters

Data simulation

Error estimation

Data simulation

• We will use 2um SiO2/Si filmstack in this example

• We will simulate Rp spectrum and look at the effects of finite wavelength(3nm) resolution and surface roughness

Data Simulation

• We have generated and cached three data sets

• We will now return to the main screen and start Compare Data Center to review this data

We will select the record we want to compare and add them to the Compare Data list

We will compare both R_rough and R_wl3nm (3 nm resolution) to the ideal data (R_ideal)

Data simulation-sensitivity

We will now look at the example of sensitivity calculations.

• We will use the same filmstack

2um SiO2/Si• We are interested in sensitivity of R (unpolarized

reflectance) measurement to tilt (angle of incidence) at 70 deg.

• Sensitivity is dR/dA (A - angle) we will use %/deg

Data simulation

We have briefly reviewed simulation options

(some new for ver. 3.0)

Please review Simulation Tutorial for more details

Brief GUI overview

Calculating Filmstack parameters

Data simulation

Error estimation

Error estimation

TFCompanion incorporates a powerful engine

to estimate measurement precision.

The idea is to propagate the precision of instrument measured parameters (e.g. reflectance, Delta, Psi etc.) to precision of Filmstack parameters

Error estimation

• Basic error estimation is available in advance version.

• Full capability is available in enterprise version

• We will discuss here only basic example

Error Estimation

• We will use 150 A SiON/Si filmstack and assume standard SE measurement

(we will a template that describes typical SE)• We will calculate the same parameters as in

the calculation example (in this tutorial)• We will be interested in measurement

precision of parameters as a function of layer Thickness

TFC ver. 3.0rc – new options

Several improvements are introduced:

1. Simulate fit option

2. Direct n,k calculation option

3. Direct measured vs. calculated review (w/o caching)

Simulate fit option

• Evaluate filmstack and compare results of simulation with the measured data

• Simulation is done directly from the main screen

• Simulated spectra match the structure (range and type) of the measured spectra

Simulate fit option

Steps to perform:

1. Load measured data

2. Load or create model filmstack

3. Use Simulate Fit button

4. Review the results

Simulate fit option

Simulate fit (cont.)

Direct n,k calculation

• In most cases n,k dispersion spectra is represented by known Tabular materials or using Parameterized approximations (Tauc-Lorentz, Cauchy, etc.)

• However, sometimes direct n,k calculation is the only option (e.g. pseudo-dielectic function of substrate, unknown materials like organic ARC).

Direct n,k calculation(cont.)

• The ability of direct n,k calculation depend on amount of measured data at each wavelength

• The number of calculated parameters should be less or equal to number of measured values (Delta, Psi at each wavelength allows calculate n,k at each wavelength)

Direct n,k calculation steps

1. Load measured data

2. Load or create model filmstack

3. Select calculated filmstack parameters

4. Calculate

5. Review the results

Direct n,k calculation (selection)

Direct n,k calculation (cont)

• We selected all n,k parameters and thickness

• Because we have SE measurement at one angle – we have too many calculated parameters now.

• We will remove calculate flag at one of k parameters in the Vis range (next slide)

Direct n,k calculation (cont.)

Direct n,k calculation (cont.)

• Normally calculation is very fast (<1s) but we have now ~880 calculated parameters so it will take few minutes

• Calculation progress dialog pops up if calculation is longer than 2 sec.

• User can stop the calculation at any time (latest results will be displayed)

Direct n,k calculation (progress)

Direct n,k calculation (review)

• Results of the calculation are displayed directly in the main screen (we use “full screen” option to review the fit)

• The fit is quite good, as expected (except for couple of points, one is where we did not calculate the k value)

Direct n,k calculation (results)

Direct n,k calculation review

• We can see all the calculation results on the main screen but now we can click on the layer and display n,k dispersion plot (and table of values)

• The plot is somewhat choppy, as expected, because we calculated each point practically independent (no smoothing effect of parameterized material model)

Direct n,k calculation (review)

Direct n,k calculation (review)

• Now we have a good approximation of n,k dispersion.

There are several options:– Save this as a new material (Use as is);– Use parameterized model (e.g.Tauc-Lorentz)

and fit it to current n,k dispersion (see Materials tutorials )

– Export the data and modify it

New features (build 12212004)

• Backside reflection correction (“incoherent layer”)

• Exciton oscillator material model –extension of harmonic oscillator model

Backside reflection correction

• Standard modeling the measurement on thick transparent substrate (e.g. glass) will produce high-frequency oscillations (backside reflection)

• One need to take into account “coherence length” of the light to correct this effect

Backside reflection correction

• Thick transparent substrate has to be set as a layer in filmstack model (substrate is “void.mat” )

• When setting the thickness of the layer – software checks if it is thick enough to be “incoherent” and warns the user

Exciton oscillator model

• Extension of Harmonic oscillator model that adds “dimensiality’ of the critical point

• Specifically designed to model dispersion of polymers (PFO, PMMA, etc.)

Conclusion

• We reviewed briefly the basic use of

TFCompanion ver. 3.0 for

• Calculation

• Data Simulation

• Error Estimation

• New features in latest release