Semiconductor Failure Analysis (FA) is the systematic process of identifying the physical root cause of device or circuit failure — using a hierarchy of destructive and non-destructive techniques to trace electrical failure to a specific defect at a specific location.

FA Flow

1. Electrical Characterization: Reproduce and characterize the failure mode (opens, shorts, parametric drift). 2. Non-Destructive Analysis: Package-level imaging before any decapsulation. 3. Decapsulation: Chemically remove package to expose die. 4. Photon Emission / OBIRCH: Locate hot spots or current anomalies on live die. 5. Physical Localization: FIB cross-section to reveal defect. 6. Defect Imaging: TEM, SEM for atomic-scale defect imaging. 7. Composition Analysis: EDX, SIMS, Auger to identify chemical root cause.

Key FA Techniques

SEM (Scanning Electron Microscopy):

• Nanometer-resolution surface imaging.
• Backscatter mode: Composition contrast.
• Secondary electron mode: Topography.

FIB (Focused Ion Beam):

• Gallium ion beam mills material with nanometer precision.
• Creates site-specific cross-sections through exact defect location.
• FIB-SEM: Combined tool — mill and image simultaneously.
• TEM sample preparation: FIB lifts out 100nm-thick lamella for TEM.

TEM (Transmission Electron Microscopy):

• Sub-angstrom resolution — images individual atoms.
• HRTEM: Crystal structure, defects, interfaces.
• STEM-EDX: Elemental mapping at atomic scale.
• Essential for sub-10nm defect characterization.

Photon Emission Microscopy (EMMI):

• Captures photons emitted from forward-biased junctions or hot carriers.
• Localizes gate oxide leakage, latch-up, ESD damage under live bias.

OBIRCH (Optical Beam Induced Resistance Change):

• Laser beam heats die; resistance change maps current flow.
• Localizes resistive shorts and buried metal defects.

Chemical Analysis

• EDX/EDS: Elemental analysis within SEM/TEM.
• Auger: Surface-sensitive elemental analysis.
• SIMS: Trace dopant/impurity profiling (ppm sensitivity).

Semiconductor failure analysis is the diagnostic backbone of quality and reliability engineering — rigorous FA drives yield improvement, process corrections, and design rule updates that prevent systematic failures from reaching customers.