Implementing smaller device dimensions requires cleaner chemicals and, more importantly, cleaner production processes. Low levels of metals such as Na, K, Li, Cu, Zn, Fe, and Ti, can alter the electrical characteristics and affect long term reliability of semiconductor devices. Here at Cerium Labs, we regularly use Vapor Phase Decomposition Inductively Coupled Plasma Mass Spectroscopy (VPD-ICPMS) to measure trace metals on silicon wafers and identify the source of contamination.
The 3 process steps are:
Step 1: Vapor phase decomposition
Step 2: Wafer surface impurity collection using a scanning solution
Step 3: Analysis by ICP-MS
The procedure starts with vapor phase decomposition, by which trace metals on the surface of a silicon wafer are released so that they can be collected. The silicon wafer is exposed to hydrofluoric acid vapor in a sealed chilling chamber.
After this, the condensate is collected by carefully scanning the entire wafer surface with a droplet of ultra-pure scanning solution. Once the droplet is collected, it is diluted and analyzed on the ICPMS.
Our VPD-ICPMS technique is capable of measuring metallic contaminants at concentrations ranging from 1E6 to 1E14 atoms/cm². VPD-ICPMS and Cerium Laboratories can help you identify the source and improve your wafer yield.