Determination of Ultratrace Amounts of Metallic and Chloride Ion Impurities in Organic Materials for Microelectronics Devices After a Microwave Digestion Method

Abstract

A digestion method was developed for the determination of ultratrace concentrations of sodium, potassium, magnesium, calcium and chloride ions. Using ETAAS and ion chromatography, the digestion method was applied successfully to the determination of ultratrace concentrations of these elements in organic materials for microelectronics devices such as photoresists, epoxy resins, and liquid crystals. Very low contamination levels were maintained throughout the procedure. The blank levels were 0.05 ng for sodium, 0.02 ng for potassium, 0.03 ng for magnesium and calcium, and 20 ng for chloride ion. The method is very effective in measuring the impurity distributions of organic materials whilst preventing their contamination from the surrounding environment and from the reagents used in the procedure.