High density epitaxial unwanted growth and its effect on planarization in FINFET process

While epitaxial growth enhances carrier mobility of PMOS devices, it introduces an unwanted growth (UG) defect which is an artifact of Silicon Germanium (SiGe) component that becomes a yield detractor in high volume manufacturing. This paper describes the effect of high density UG defect on downstream CMP processes, detection methods using both defect scan and in-situ metrology. Use of high resolution defect scans and high throughput inline metrology was the key to detection of non-conforming material.