This article introduces a method for analyzing low ppb levels of anions on wafer surfaces using capillary electrophoresis. This method has the advantages of low sample consumption, low cost, high speed, and short turnover time.
The document details a method for analyzing low ppb levels of anions (such as chloride, sulfate, and nitrate) on semiconductor wafer surfaces. It highlights that capillary electrophoresis (CE) is suitable due to low sample consumption, high speed, and short turnover times compared to other methods.
The procedure requires using 500 µL of ultrapure water to completely wet a 200 mm wafer.
A capillary is considered equilibrated when migration time repeatability is less than 2% RSD.