Paul Winer

Application of advanced micromachining techniques for the characterization and debug of high performance microprocessors

Micromachining techniques such as focused ion beam milling have become an integral part of the design debug cycle at many companies for providing fast verification of bug fixes in silicon. With flip chip packaging becoming more prevalent for future high performance processors, it is necessary to perform circuit edits and bug fixes on the silicon while the chip is packaged in the flip chip package. With this technology, however, conventional frontside probing and traditional circuit rewiring of packaged devices are not practical. We have developed a combination of new micromachining techniques for directly accessing metal signals from the backside of the chip. Here we will describe this new process, the technologies used, and some basic applications.

Laser-assisted chemical etching for embedded microchannels and overhanging microstructures on Si/SiO2 substrates

The feasibility of fabricating buried (embedded or subsurface) microstructures between silicon and silicon oxide using laser-assisted chemical etching (LACE) in chlorine atmosphere is demonstrated in this article. An associated LACE ablation model and sample calculations based on one-dimensional thermal analysis and chemical kinetics are presented. A strategy for optimizing the laser process for 3D micromachining is outlined. Potential applications of such fabricated microstructures include microfluidic MEMS for transducers and electronic cooling.

Novel optical probing and micromachining techniques for silicon debug of flip chip packaged microprocessors

Methods and techniques for micromachining and probing C4 packaged microprocessors from the silicon backside are described. The micromachining technique is based on using a combination of Laser Chemical Etching and Focused Ion Beam milling to open precision probe holes and perform circuit editing from the backside. A method to optically probe flip chip packaged CMOS microprocessors is also described. The optical probing technique utilizes an infrared laser to probe diffusions directly through the silicon backside without the need to mill probe holes.