Highly Manufacturable 7 th Generation 3D NAND Flash Memory with COP structure and Double Stack Process
Jun Hyoung Kim, Yong-Sik Yim, Joonsung Lim, Hyun‐Suk Kim, Eun Suk Cho, Chadong Yeo, Woongseop Lee, Byung-Kwan You, Byoungil Lee, Min Kyu Kang, Woojae Jang, Youngho Kwon, Keehong Lee, Jae-Duk Lee, Myeong-Cheol Kim, Jin-Yub Lee, Sung‐Hoi Hur, Su Jin Ahn, Hyeongsun Hong, Yu Gyun Shin · 2021
A novel 3D NAND Flash memory device with 17X WL (Word line) layers has been successfully developed. COP(Cell Over Peripheral) Structure has been applied, improving tR and tPROG by 11% and 20%, respectively. Compared with our previous product(6th generation), the bit density is increased by 70% through cell volume scaling and COP structure. Several breakthrough processes have been successfully combined to achieve this new structure. Double stack process, low stress W(tungsten), MSE(Multi Step Etch), and channel hole side-wall butting etc. In addition, the double stack process was applied to significantly improve the channel hole profile. As a result, better cell operation characteristics were achieved.