Learning Forum

[SAURAV GAUTAM]

Hi,

I can't observe high oscillation in reflectance spectrum of TSV due to  interference effect. In real experiment, To measure hole depth in a structure it's reflection is measured which has high frequency oscillations. The height can be measured by using DFT. I am not getting similar oscillation in simulation. The reflection spectra in lumerical simulation is very smooth. what could be the reason?

Image Source: A Hybrid Non-destructive Measuring Method of Three-dimensional Profile of Through Silicon Vias for Realization of Smart Devices

https://doi.org/10.1038/s41598-018-33728-w

 

thank you

[Guilin Sun]

 

Some times it can be difficult to compare experiment and simulation, in particular the material and geometry. Please refer to this post: 

Ansys Insight: Why my simulation result is different from published paper or experiment?

FDTD solves directly the Maxwell Equations. So it should give roughly the same physics, if not exactly the same due to discretization, and if the settings are correct and the device is exactly the same. So pleae carefully check your device and simulation settings.

[Guilin Sun]

One more thing:  it seems their light source has limited coherent length, eg, partial coherent, like LED. Please confirm what light source they used in experiement.

[SAURAV GAUTAM]

thank you for your support

[SAURAV GAUTAM]

in simulation i am using plane wave source. It should follow the reflectometry equation for reflection from surface at different height.

[Guilin Sun]

This is for sure. Please refer to this article: https://optics.ansys.com/hc/en-us/articles/360034915753-Tips-for-accurately-measuring-reflection-in-an-FDTD-simulation

I guess there are some discrapancies in some properties between experiment and simulation. As mentioned in the forum post I shared with you, it can be more challenge to compare the experiment, since there are somgthing people do not know exactly.

FDTD solves Maxwell Equations so it will count all coherence physics.