Invited Paper MC-ThA3
What Is Needed and What Is Practically Available for Small Area, Small Depth, Chemistry Sensitive Analysis in the Semiconductor Wafer Processing Industry
The continuing health of the semiconductor industry depends on the insatiable demand to reduce CD (critical dimensions), eg gate length and thickness, interconnect line dimensions, barrier layer thickness. For needed analytical methods, this translates into improved spatial resolution (area and depth). In addition, because of (a) the drive towards where everything is interface, (b) the introduction of many "non-traditional" materials (eg Cu, low k, high k), and (c) a general push towards even higher yields, the need for chemical state information has increased and will continue to increase. In this paper I review, from a wafer processing perspective, what analytical instrumentation is needed, compared to what is actually available. I also try to define the differences in instrumentation needs for "analytical laboratory" usage and "metrology usage." Though I will concentrate on techniques which are thought of as surface sensitive (eg electron spectroscopies), there is no longer any practical reason to distinguish these from techniques which are not mainly thought of as surface sensitive (eg EDS, Raman). The reason is twofold. First, we need information over a range of depth. Second, such techniques can be, and have been, made more surface/interface/small area applicable than has been traditional. Finally, since our particular interests have to do with small particle defects during wafer processing, I will give examples to illustrate our current capabilities and our unmet needs.