The quantitative measurement of Cu, Fe, Zn, Ca, and Br in the native oxide of prime silicon wafers taken from sealed cassettes of four major silicon vendors was completed using total reflection x‐ray fluorescence (TXRF). The results indicate TXRF can detect these elements on a range of commercial wafers and can differentiate between these commercial cleaning and packaging processes. In particular, the average Cu levels for wafers in cassettes A, B, C, and D were: , respectively, where the high Cu in cassette B was nonrandom and ranged from . In contrast, the average Fe levels for cassettes A, B, and C were , respectively, while Fe could only be detected on five of the twenty‐five wafers in cassette D. Furthermore, the average Zn levels for cassettes A, B, C, and D were: . It is concluded that TXRF can be used for cleaning process development, process control, or quality audit.