It’s been a while since I posted the last blog. While on sabbatical and on the go since the beginning of the Spring semester I don’t get much time to do fun things such as occasional blogging. 

At various times over the years, various elements of semiconductor science and engineering were defining progress. Not long ago, when silicon was a sole ruler, the progress was riding mainly on the shoulders of improvements in process technology. At that time, developments that were punctuating the advancements were basically synonymous with what was going on in high-end logic and memory IC technology.

In the very old days ion implantation pushing aside doping by diffusion was a hit (even earlier diffusion replaced alloyed junctions by the way), then RIE came about as a savior in etch technology, then its HDP version, then CMP, supercritical fluid cleaning, etc.  And of course photolithography with its developments was continuously looming over the horizon –steppers, g-line, i-line, excimer lasers, phase shift masks, immersion lithography were defining the progress.

While all this was happening not much was changing in materials (with an exception of copper replacing aluminum as an interconnect material) and device configuration. It was all based on silicon (single-crystal Si, poly-Si, SiO₂, Si₃N₄) and planar CMOS was a device benchmark.

During the last decade or so the paradigm has shifted significantly. It is all about the materials and elaborately configured materials systems these days. Even the latest process technology related breakthrough, introduction of ALD into the mainstream manufacturing, was driven solely by the material related needs (introduction of high-k gate dielectrics). Other than that, on both ends of the line, front and back, high-end material and device engineering determine the progress. For instance, high mobility channel materials, SiGe and SiC stressors, high-k dielectric gate stack engineering, new generation of ILDs , TSVs, etc,etc.…. Even silicon substrate itself must be heavily engineered to meet emerging needs. Furthermore, needs of photovoltaics, organic semiconductor technology, printed large area electronics and photonics, flexible substrates, MEMS/NEMS, opportunities in advancements in TFT technology, 2D (graphene for instance), 1D (nanowires), zeroD (nanodots) material systems, ferromagnetic semiconductors  etc. etc., spread semiconductor innovation efforts well beyond mainstream digital IC territory.

All this is breathing fresh air into semiconductor research. It is no longer that one must have 300 mm wafer capability, at least class 10 clean-room and 193 nm exposure tools to do research that have any relevance. The window for innovations is wide open and the reliance on the highest end tool is lesser than in not too remote past. Let’s hope funding will be sufficient to allow semiconductor R&D community to fully spread its wings

The recognition of the IEEE International Electron Device Meeting (IEDM) as a prime technical/scientific event of the year is pretty well established in semiconductor community worldwide. Breaking with tradition, the 2009 IEDM will be held next week in Baltimore, MD, rather than in Washington, D.C. Other than this, IEDM 2009 projects itself as yet another meeting in the series worth attending.

“Selectivity” was always an issue in etch technology where etching of one material should not affect other materials on the surface of the wafer. “Selectivity” was not a top-of-the-list issue during standard cleaning operations of silicon wafers. That is not until MOS gates structures in state-of-the-art CMOS technology (45 nm and below) have become complex, multi-material mazes involving various high-k dielectrics with capping layers and metal gate contacts.

The 11^th International Symposium on Cleaning and Surface Conditioning Technology in Semiconductor Device Manufacturing was held during the ECS Fall Meeting in Vienna (see complete list of papers presented). I will comment on the trends emerging in this important component of semiconductor manufacturing in the forthcoming blog(s).