Improved cleaning module after tungsten etch

Integrated dry photoresist and residue removal is increasingly being implemented over traditional dry resist strip and wet residue removal process flows. The primary motivation is to improve the wafer surface cleanliness after a cleaning module in order to improve device performance. A case study will be reviewed for the post tungsten etch cleaning module. Using the traditional cleaning sequence of dry/wet strip caused unacceptable titanium undercut and electrical leakage. The improved cleaning module for integrated dry resist and residue removal increased device performance, controlled the titanium undercut and reduced the time in the wet strip solvent bath by over six times. Additional benefits such as decreased defects and improved SACVD coverage were also results of the integrated cleaning module. A study of the original problem, the replacement process and optimization are provided with defect data, cross sections and electrical measurements.