Mueller Matrix Scatterometry is an advanced form of optical scatterometry that measures the full 4×4 Mueller matrix of a sample — capturing the complete polarization response (diattenuation, retardance, and depolarization) rather than just the ellipsometric parameters ($Psi, Delta$), providing richer information about structural asymmetries and complex profiles.

Mueller Matrix Advantages

• 16 Elements: The 4×4 Mueller matrix has 16 elements — far more information than the 2 parameters ($Psi, Delta$) from standard ellipsometry.
• Symmetry Breaking: Off-diagonal Mueller matrix elements are sensitive to structural asymmetries (line tilt, non-uniform profiles).
• Depolarization: Depolarization from surface roughness, CD variation, or overlay errors can be measured directly.
• Cross-Polarization: Cross-polarized elements reveal features invisible to co-polarized measurements.

Why It Matters

• Asymmetric Profiles: Detects line tilt, footing, and asymmetric sidewalls that standard ellipsometry misses.
• Overlay: Mueller matrix elements are sensitive to overlay errors — enables advanced overlay metrology.
• Process Control: Additional Mueller matrix elements provide more process-relevant information per measurement.

Mueller Matrix Scatterometry is the complete polarization portrait — capturing every aspect of light-structure interaction for high-information metrology.