Determination of Si and Cu in Al target metal used in a semiconductor process by inductively coupled plasma-atomic emission spectrometry

In this work, a method for the determination of Cu and Si in Al target metal used in a semiconductor process was developed based on inductively coupled plasma-atomic emission spectrometry (ICP-AES). Wet acid digestion and high-pressure acid digestion, open and closed systems, respectively, were employed to dissolve the Al target metal containing 0.5% (w/w) Cu and >0.2% (w/w) Si. Recovery of 45% was obtained for Si, when hydrochloric acid was used for wet acid digestion. The recovery increased to 90% in high-pressure acid digestion, or wet acid digestion with the use of sulfuric acid instead of hydrochloric acid. This indicated that Si was lost during the wet acid digestion if hydrochloric acid was used. For application, three kinds of aluminum target metals containing more than 0.2% (w/w) Si, along with 0.5% (w/w) Cu, which are commonly used in semiconductor process, were analyzed with standard addition using ICP-AES.