Inline monitoring of SiGe strain relaxed buffers (SRBs) using high-resolution X-ray diffraction: AM: Advanced metrology

We describe the use of high resolution X-ray diffraction (HRXRD) for inline metrology of strain relaxed buffer (SRB) layers and epitaxial layers grown thereon. The use of SRBs as a virtual substrate is a promising candidate for advanced CMOS logic at the 7 nm technology node and presents some unique challenges to traditional HRXRD measurements. To overcome these challenges, reciprocal space maps (RSMs) were employed to characterize different films on SRBs. We discuss the measurement strategies and recent improvements to X-ray metrology tools that enable these measurements for inline process control. Furthermore, advances in the automated data extraction and analysis are introduced.