In-fab assessment of heat budget in 3D NAND flash devices using terahertz wave-based metrology system

In this study, we introduce a non-destructive method for evaluating the heat budget in 3D NAND flash memory devices, utilizing an in-fab terahertz wave-based metrology system. Our approach enables the monitoring of electrical property variations in the devices, resulting from hydrogen concentration changes due to heat-related semiconductor fabrication processes. In this work, we demonstrate a robust correlation (R2 =0.99) between hydrogen concentrations in thick SiO
2
layer and transmitted THz signals in 3D NAND structures. This finding highlights the promise of in-fab THz-based measurement tools for examining dopant variation within high carrier density regions of transistors during the manufacturing process.