Recent developments in analytical techniques for characterization of ultra pure materials—An overview

With continual decrease of geometries used in modern IC devices, the trace metal impurities of process materials and chemicals used in their manufacture are moving to increasingly lower levels, i.e. ng/g and pg/g levels. An attempt is made to give a brief overview of the use of different analytical techniques in the analysis of trace metal impurities in ultrapure materials, such as, high-purity tellurium (7N), high purity quartz, high-purity copper (6N), and high purity water and mineral acids. In recent times mass spectrometric techniques such as ICP-MS, GD-MS and HR-ICP-MS with their characteristic high sensitivity and less interference effects were proved to be extremely useful in this field. A few examples of such application studies using these techniques are outlined. The usefulness of other analytical techniques such as F-AAS, GF-AAS, XRF, ICP-AES and INAA was also described. Specific advantages of ICP-MS and HR-ICP-MS such as high sensitivity, limited interference effects, element coverage and speed would make them powerful analytical tools for the characterization of ultrapure materials in future.