Titanium disilicide formation for detection of temperature drift and oxygen leak in rapid thermal processing tool

In this paper, titanium film thickness in the range of 40nm to 125nm was characterized for optimizing the thickness-temperature combination for titanium disilicide (TiSi2) formation which can be used as a detecting temperature drift. Post silicidation sheet resistance was measured to analyze the integrity of anneal process. Scanning Electron Microscope and X-ray Photoelectron Spectroscopy techniques were employed to validate thickness of titanium film and determine elemental composition respectively. Atomic Force Microscopy was employed for characterizing roughness of the film. This paper recommends a set of process parameters and titanium film thickness for efficiently using TiSi2 sheet resistance for detecting temperature drifts in the window of 600°C to 650°C. Besides, the silicidation process is also shown to be useful in detecting O₂ leak in the chamber, utilizing the discoloration of titanium when reacting with oxygen under heat.