13.1 A 1.33Tb 4-bit/Cell 3D-Flash Memory on a 96-Word-Line-Layer Technology

Abstract

Since 3D-Flash memory took over for 2D-Flash memory, chip capacity has continuously improved [1-3]. In the 2D-Flash era, 2b/cell (MLC) offered higher performance and reliability, while a 3b/cell (TLC) offered the lowest cost. Thanks to a larger feature size, 3D Flash cell reliability is much better than that of 2D. As a result, TLC 3D-Flash became the mainstream non-volatile memory, since it satisfies most market requirements in both performance and reliability. To meet the continuously growing market demand for higher capacity and lower cost, a 4b/cell (QLC) 3D-Flash memory in a 96-WL-layer technology is presented. It achieves an 8.5Gb/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area capacity, which is 42~50% greater than the 3D-Flash memory reported in [2,3]. A chip micrograph and a table summarizing key features is shown in Fig. 13.1.7. The total 1.33Tb capacity is the highest single Flash memory chip capacity reported thus far.