Impact of Moisture From Passivation on Endurance and Retention of NAND Flash Memory

This study investigates how the passivation process impacts floating gate type NAND flash reliability. The hydrogen post-metallization anneal step sequence in the process flow and film deposition of passivation layer significantly influence endurance and retention performance. Experimental results indicate that the degradation mechanism is the water diffusion model. The optimized process flow of the passivation layer is proposed as well.