BASIC STUDIES OF ULTRATRACE CHEMICAL-ANAL YSIS FOR METALLIC ELEMENTS IN SEVERAL SEMICONDUCTOR-MATERIALS

The reduction of the blank levels of analytical procedures: has long b een an important consideration in analytical chemistry. Continuous imp rovements in the sensitivity of analytical techniques have necessitate d the mitigation of the contamination levels in many ultratrace proced ures. Chapter 1 reviews the history of ultratrace analysis for the int roduction. Chapter 2 outlines the reduction of analytical blanks from containers. A mirror-polishing technique was developed for treating fl uorocarbon polymers surfaces using high-precision diamond cutting tool s. A degree of surface smoothness of 0.1 mu m PTV (peak to valley) was obtained. Ultratrace analysis contamination levels for contamination fabricated from such polymers were reduced by more than 1 order of mag nitude relative to those prevalent in a commercially available contain er. Chapter 3 discusses the determination of an ultratrace analysis of inorganic semiconductor materials, such as silicon wafers, copper lay ers, barrier metals, and so forth. Silicon wafers 0.01 to 10 mu m thic k could be dissolved by controlling the acidities of HF and HNO3 in th e etching solution. When a few hydrogen annealed wafers were analyzed by this method, different annealing treatments of silicon wafer were f ound to have clearly different depth-profiles of elements. Chapter 4 c onsiders the determination of an ultratrace analysis of organic semico nductor materials. A digestion method was successfully used to determi ne ultratrace concentrations of Na, K, Mg, Ca, and Cl in organic mater ials. The method is very effective in measuring the ions of organic ma terials whilst preventing their contamination from the surrounding env ironment and from the procedure.