Digital Age in the By Kevin
Arc P h o t o I l l u s t r a t i o n b y S t r o b o P h o t o , © 1 1 / 0 1
A Cost Comparison of Alternative Book Storage Strategies
Most academic libraries have a limited amount of space to house their collection. This paper develops a cost methodology to use in deciding the location (on-campus or off-campus), type of access (open or closed stacks), and type of shelving (regular or compact) to augment existing stacks of the library. A number of factors are considered in the model including the cost of constructing storage facilities, the cost of selecting materials that are to be moved to storage, the cost of processing materials at the local library in anticipation of their move to storage, the cost of transporting materials from the library to the storage facility, processing costs at the storage facility, and circulation costs from the storage facility. Both library and user costs are included in the models, and cost comparisons between alternative storage strategies are made. Data from a specific case study at the University of California, San Diego, are used to illustrate the model.
Bevel RIE application to reduce defectivity in copper BEOL processing
Bevel etch used during wafer fabrication for semiconductor devices is discussed. In this case, the bevel etch process was utilized in middle of the line processing (MOL) to reduce back end of line (BEOL) defectivity. Tungsten and titanium nitride films, from the formation of contacts to the transistors, extend into the bevel region of the wafer and have been shown to initiate arcing. This can spread foreign material defects on the front side of the wafer in various BEOL post processing steps including subsequent reactive ion etching, SEM metrology and film depositions. The bevel etch tool confines a plasma etch to the outer edge of the front side of the wafer (which can be individually adjusted) and can remove dielectric, organic and Ti/TiN/W films using a fluorine based chemistry.