The Center for Advanced Life Cycle Engineering

Failure Analysis

Having completed the non-destructive analysis, the next step is to use destructive sample preparation techniques to reveal the internal structure of the sample. As much information as non-destructive evaluation (NDE) provides, destructive evaluation is often necessary to verify the failure mechanism and root cause.

Two initial techniques in destructive evaluation or electronic products are decapsulation/delidding and microsectioning. Chemical decapsulation consists of dissolving the plastic encapsulant using fuming nitric or sulfuric acid and delidding involves mechanically removing the lid from a hermetic package. Both decapsulation or delidding allow for internal examination of the die and interconnects by optical, electron, magnetic, or emission microscopy. Additional destructive evaluation can also be performed, using either focused ion beam imaging or transmission electron microscopy. These techniques permit detection of bond pad corrosion, passivation cracking, ball bond lifting, stress driven diffusive voiding, electromigration, metallization corrosion, and other failure mechanisms at the die level.

Microsectioning, also known as cross-sectioning, is performed to reach a surface which reveals an important feature of the sample, such as intermetallic formation in wire bonds or delamination at the fiber/epoxy interface in printed circuit boards. The cross-sectioned surface is often examined using optical microscopy, electron microscopy, and energy dispersive spectroscopy.

Mechanical testing, FTIR, contact resistance, and popcorn assessment.

Introduction

Electrical Testing

Non-Destructive Evaluation

Destructive Evaluation

Microsectioning

Decapsulation/Delidding

Microtesting

*Optical Microscopy

*Scanning Electron Microscopy (SEM)

*Energy Dispersive Microscopy (EDS)

Focused Ion Beam (FIB) Imaging