A Few Tools of the Trade

Scanning Optical Microscope (SOM): SOM-based techniques can be used in failure analysis. There are several SOM-based techniques two of which are TIVA/SEI and OBIRCH.

Optical Waveform Probing (OWP): Optical Waveform Probes allow measurement of waveforms from the backside of an integrated circuit. Backside diagnostic techniques are important because many have adopted flip-chip packaging. Backside techniques are thus gaining popularity even for front-side packaged devices.

Focused Ion Beam (FIB): Using a finely focused ion beam, FIB can perform product failure analysis at a detail much finer than previously possible. The investigator may quickly and selectively remove dielectric or metal layers for probing and material analysis of underlying surfaces. Rapid cross-sections of circuitry can also be performed with sub-micron accuracy.

Scanning Probe Microscopy (SPM): Scanning Probe Microscopy offers a variety of new techniques that go beyond topography imaging with Atomic Force Microscopy. Examples are mapping of carrier distributions, electric potential, local current and heat.

Scanning Electron Microscopy (SEM): In failure analysis, electron microscopy is an extension of optical microscopy. The use of electrons instead of a light source provides significantly higher magnification, unique imaging and the ability to perform elemental analysis.

Energy Dispersive Microscopy (EDS): EDS can be key in determining solder composition, examining plating quality, determining the location and source of contamination and performing reverse engineering.

X-ray Microscopy: This tool permits nondestructive assessment of internal damage, defects and degradation in the IC die. Illuminating a die with x-ray energy provides images based on material density that allows “viewing” of solder voiding, wire bond sweep and wire bond breakage. Further, x-ray can reveal anomalies such as die attach voiding, solder pooling or die shifting.

Scanning Magnetic Microscopy (SMM): Failure site identification is a critical step in effective analysis. A recent detection technology, SMM, uses the magnetic fields given off by current-carrying traces/metallizations to pinpoint the locations of shorts, opens and other electrical faults.

Scanning Acoustic Microscopy (SAM): Scanning acoustic microscopy (SAM) uses the absorption and reflection of ultrasonic waves in a sample. This technique is especially sensitive to any change in acoustic impedance such as debonds or delamination (as can occur in a plastic encapsulated device). These types of faults are difficult to detect using X-ray techniques. Applications for SAM include die-attach integrity, characterization of wire bonds and identification of cracks in the die.

DD & S provides expert assistance with the design and implementation of Failure Analysis work. This effort is a special service beyond the basic cost of the die or wafers and is quoted as a separate item upon request.


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