Comprehensive Bath Monitoring of Ruthenium Wet Deposition and Etching Processes

The semiconductor industry has mostly employed dry processes for Ru thin layer deposition and etching. Cost effective wet approaches remain limited for high volume production. One of the obstacles is the precise process control of the sophisticated solutions. In this report, typical electroless deposition and etching of ruthenium processes were analyzed by various techniques, including real-time UVVIS, near-infrared, Raman spectroscopy, reagent spectrophotometry, and inductively coupled plasma optical emission spectroscopy. Corresponding methods were developed for automatic and comprehensive characterization of every component without interreferences from the solution matrix or by-products in the process.