Total-reflection X-ray fluorescence (TXRF) spectrometry with no chemical preconcentration, often called "straight-TXRF", is now widely used in the semiconductor industry. The small detection area of TXRF enablesmapping measurement of contamination of the semiconductor surface, which is very useful in process characterization. However, the small detection area had been believed to limit rapid whole-surface analysis. Contrary to this general understanding, in this study we demonstrated that a new method, called "sweeping-TXRF", which is essentially short-time multipoint mapping by straight-TXRF, can rapidly provide an average concentration. A considerable problem of this method is the contribution of errors in glancing angle and areal element distribution to the fluorescence. Using statistics, we examined the errors and demonstrated that most of them are canceled and are not significant in actual semiconductor applications. The results of an experiment that measured localized 6 x 10(10) atoms cm(-2) nickel contamination supported the above conclusion. Applying sweeping-TXRF to existing TXRF instruments is easy-the only requirement is a small software modification. We believe that sweeping-TXRF will be utilized for rapid whole-surface analysis in many fields, especially in the semiconductor industry.
Among laboratory mistakes, "specimen mix-up" is the most frequent and the most serious. According to the Clinical Chemistry Laboratory Error Report of Toranomon Hospital, specimen mix-up was often detected when there were many large discrepancies between the results of a test and the results of a previous test. We present here a checking method to detect specimen mix-up. The method, which we call the "multivariate delta check" method, is an extension of the "delta check" method first presented by Nosanchuk and Gottmann (Am. J. Clin. Pathol. 62:707, 1974). Clinical evaluation has demonstrated the effectiveness of the method.
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