1. FIB, Ellipsometry, Interferometry...
Tools & Techniques
FIB, Ellipsometry, Interferometry...

2. FIB, Ellipsometry, Interferometry...
Tools & Techniques
FIB, Ellipsometry, Interferometry...

3. Index Focussed Ion Beam (more of a preparatory tool)
Thickness measurements
Ellipsometry, Interferometry, pulse technology
SIMS
1-Jan-19

4. FIB Similar to sputtering in some respects
Generates beams with Liquid Metal Ion Source (LMIS)
typically Gallium
Steered using electric and magnetic fields
Energy ~ 100 keV (flexible)
Used for micro machining
In Failure Analysis (FA)
Use voltage contrast method in SEM to identify failing via in a chain
Use FIB to ‘cut’ the failing via
Tilt the sample and obtain SEM
Implant dopant in select areas with out mask (mainly for modification)
1-Jan-19

5. Thickness Measurement
Optics: Amplitude, Phase, Polarity
Linearly polarized light, circularly and elliptically polarized
Phase difference = 90 degree, circle
Phase difference = 0 degree, linear
Polarizer / Analyzer, Quarter Wave Plate
Fast axis, slow axis
Combination of Polarizer + QW Plate can change linear poliarized to elliptical polarized and vice versa
Reflection in thin film:
P and S components undergo different phase shifts
polarization of reflected light depends on film thickness and refractive index
and wavelength of light
1-Jan-19

6. Thickness Measurement
Optics: Amplitude, Phase, Polarity
Linearly polarized light, circularly and elliptically polarized
Phase difference = 90 degree, circle
Phase difference = 0 degree, linear
Polarizer / Analyzer, Quarter Wave Plate
Fast axis, slow axis
Combination of Polarizer + QW Plate can change linear poliarized to elliptical polarized and vice versa
Reflection in thin film:
P and S components undergo different phase shifts
polarization of reflected light depends on film thickness and refractive index
and wavelength of light and angle of incidence
1-Jan-19

7. Ellipsometer
Stokes’ Ellipsometer
©Gaertner Scientific
1-Jan-19

8. Ellipsometer Can measure thin metallic films (semi transparent)
Non contact, non destructive technique
Can also vary angle
Angstrom level accuracy
Newer techniques
Stokes Ellipsometer
Does not have moving parts (polarizer or analyzer)
1-Jan-19

9. Interferometry © Nanometric
Light from 200 to 800 nm (Deuterium and W or Halogen lamps)
Reflected light intensity vs wavelength detected
Film stack quality must be known
Not as accurate as ellipsometery
Also cannot be used (accurately) to determine refractive index
real and imaginary quantities
Refractive index, exitinction coefficient
Cheaper than ellipsometer
(Another name; Spectral Reflectance )
© Nanometric
1-Jan-19

10. Interferometry
Wavelengths used from about 200nm to IR (1700 nm) in some cases
Plot of model vs experimental (to check for convergence)
If film is very thin (less than one cycle of oscillation), difficult to measure
many stacks are also difficult to measure
May not give unique solution
Remember n and k depend on wavelength
Even for reasonably thick film, (single layer), approx thickness must be known
1-Jan-19

11. Pulse Technology Use a laser pulse to heat the surface
Thermal expansion and contraction result in ultrasonic sound generation
Various interfaces reflect the pulse
Pioneered by Rudolph Tech
1-Jan-19