For the purpose of searching information on the desired purity specification optimum of refractory metal/silicide materials to be used by the IC manufacturer, the views of a material supplier are presented. In particular, ‘‘high purity’’ does not necessarily mean high quality, because all impurities are not equal. Samples of materials representing currently achievable production technology have been collected and analyzed (principally by spark‐source mass‐spectrometry). Impurities are grouped into three categories, the known sensitive elements (alkalis and α emitters particularly uranium/thorium), the major impurities (mostly the 4th period transition elements) which define the overall purity, and other impurities in lesser concentrations with ill‐defined effects on material usefulness. The uranium content as a source of soft error is discussed in some detail. A specification for refractory metals/silicides for VLSI application is proposed for industry consideration.