The SIL is now an essential component of the modern FA lab. But the SIL has very specific requirements to produce good results: and the aplanatic SIL (or ASIL) has even more stringent requirements. In particular, it requires a very specific sample thickness, and a very flat surface. In addition, there are situations where a commercial SIL lens is not compatible with the requirements at hand. This paper describes a method for fabricating an in-situ SIL that can be adjusted for different sample thicknesses, using a combination of materials and techniques that are both readily available and easily learned. In contrast to diffractive lenses, our SILs are much more efficient with regard to delivering a focused laser beam to the spot of interest, and do not require the use of a FIB to fabricate them.

Silicon’s index of refraction has a strong temperature coefficient. This temperature dependence can be used to aid sample thinning procedures used for backside analysis, by providing a noncontact method of measuring absolute sample thickness. It also can remove slope ambiguity while counting interference fringes (used to determine the direction and magnitude of thickness variations across a sample).

Failure analysis of RFIC’s can be a challenging problem, particularly as frequencies ascend into the medium to high GHz region. As frequency goes up, active probes become less and less accurate due to capacitive loading of circuit nodes, and capacitive coupling of stray signals into the probe from nearby circuit traces. We have found that Laser Voltage Imaging (LVi) offers an alternative measurement technique that can avoid these problems. But our work also showed that there are unusual failure signatures which appear as signal frequencies go up. A combination of LVI and RF-SDL was found to yield the best result.

Development of a reliable mechanical decapsulation procedure for an IC process incorporating Cu and organic passivation layers resulted in a better understanding of the polishing process. The improved polishing technique --Deterministic Polishing-- is an adaptation of an advanced polishing technology employed by the optics industry to fabricate highly accurate optical elements. These results can be applied to a broad class of polishing applications.

This article presents a novel tool designed to allow circuit node measurements in a radio frequency (RF) integrated circuit. The discussion covers RF circuit problems; provides details on the Radio Probe design, which achieves an input impedance of 50Kohms and an overall attenuation factor of 0 dB; and describes signal to noise issues in the output signal, along with their improvement techniques. This cost-effective solution incorporates features that make it well suited to the task of differential measurement of circuit nodes within an RF IC. The Radio Probe concept offers a number of advantages compared to active probes. It is a single frequency measurement tool, so it complements, rather than replaces, active probes.