Stress control in thick hydrogenated amorphous carbon films to mitigate stress-induced defects in semiconductor processes

This study addresses stress-induced defects in hydrogenated amorphous carbon layers (ACL) used as hard masks in Vertical NAND (VNAND) memory fabrication. The addition of N₂ gas during ACL deposition enabled precise control of stress in ACL films deposited at high temperatures. This stress control reduced the film's tensile stress, thereby mitigating arcing defects and delamination issues caused by high stress. It was confirmed that film stress was controlled by changes in hydrogen content and adjustments to the coefficient of thermal expansion without adversely affecting other film properties from the analyses of Raman spectroscopy and Fourier transform infrared spectroscopy. This approach has been demonstrated to enhance productivity and yield in high-volume semiconductor manufacturing. Our findings provide valuable insights for managing film stress in next-generation semiconductor devices, including High Bandwidth Memory and Bonding VNAND.