Broad Ion Beam “Slope Cutting” Technique for Cross Sectional SEM Specimen Preparation of Semiconductors

Extract

Cross sectional SEM specimens are routinely prepared for process monitoring/development, fabrication problem solving and failure analysis in semiconductor industries. A considerable variety of established methods are already in place for production of these specimens. They include: mechanical polishing, manual/automated cleaving, wet chemical etching and focused ion beam (FIB) milling. This report covers a new approach to the preparation of such specimens utilizing a broad ion beam technique. The technique consists of three steps, I) perpendicular “slope cutting” to expose the profile of the layers/features in the starting wafer, II) etching of the cut surface to delineate the microstructures and III) coating the specimen with a conductive thin film to prevent charging effects in the SEM. All three steps are carried out in a dedicated broad ion beam instrument, designed initially to etch and coat SEM specimens in one vacuum chamber [1]. The entire three-step process can be completed in one hour.