Abstract: Methods for selective measurement and monitoring of multiple base chemicals in processing solutions are provided. Methods include providing a processing solution including a plurality of base chemicals and performing a first analytical method, such as measuring a conductivity of the solution blend, in combination with a second analytical method, such as titration or pH measurements of the solution. From such measurements, a concentration of one or more base chemicals can be selectively determined. In such methods, multiple bases in a same processing solution are advantageously selectively measured and monitored accurately.

Abstract: Techniques including methods and apparatuses for inert real-time measurement and monitoring of metal and acid concentrations in a processing solution are provided. Methods include performing an analytical method (e.g., spectral measurements) of the processing solution to determine a metal concentration and performing another analytical method (e.g., density measurements) of the processing solution to determine an acid concentration with compensation of raw results based on the determined metal concentration. The determination of the acid concentration can also include compensation of raw results based on another analytical method (e.g., temperature measurements) of the processing solution. The analytical methods can be performed in any order or in parallel. Both metal and acid concentrations in the processing solution can therefore be inertly and continuously measured and monitored in real time.

Abstract: Techniques including methods and apparatuses for selective measurement and monitoring of halide concentrations in processing solutions for iron triad metals and their alloys are provided. Methods include monitoring of a halide ion, for example, based on a first analytical method such as conductivity with a compensation of the results for a main metal concentration such as a second analytical measurement of concentration of an iron triad metal (e.g., nickel (Ni)). From such measurements, a concentration of certain halide ions can be selectively determined.

Abstract: Low concentrations of silicon in an etchant solution comprising phosphoric acid, an organo-silicon compound and water are analyzed by adding predetermined concentrations of a carboxylic acid and fluoride ions to a test solution comprising a predetermined volume of the etchant solution, and measuring the potential of a fluoride ion specific electrode (FISE) in the test solution. Reaction with silicon ions in the test solution reduces the concentration of fluoride ions, which are present in stoichiometric excess, so that the silicon concentration of the etchant solution can be determined from the difference between the predetermined and measured concentrations of fluoride ions in the test solution.