Advances in X-ray Reflectivity (XRR) and X-ray Fluorescence (XRF) Measurements Provide Unique Advantages for Semiconductor Applications

We have developed a thin-film metrology tool that fulfills the metrology requirements for the production of 65nm node technology and beyond. This tool combines X-ray Reflectivity (XRR) and X-ray Fluorescence (XRF) measurements to provide accurate, high throughput, measurements. Improvements in both the XRR and XRF configurations were made to allow high throughput measurements on films as thin as 0.5 nm. The source intensity for the XRR measurements was increased using focusing X-ray optics. Wafer alignment, which is critical for XRR measurements to be accurate, is done using both X-rays and lasers to reduce the time required. A monochromatic X-ray source is used for XRF measurements since peak-to-background ratio is extremely important when detecting the XRF signal from ultra-thin films.