The integration process of W-plug landing on Cu line in 28nm-node flash memory and beyond

The integration process of W-plug landing on Cu line has been investigated systematically step-by-step. The process is divided into four steps, including pre-clean, Ti, TiN, and W depositions. The over-all contact resistance of the structure is successfully reduced by reactive plasma treatment for pre-clean, Ti deposition, adding the cycles of plasma treatment for TiN by metal organic chemical vapor deposition, and increasing the temperature of W deposition.