懂IT的，对长江存储有了解的，来说说232层堆叠3D NAND Flash技术

YMTC delivered on its roadmaps to achieve a mass-production 232-layer 3D NAND flash memory, beating entrenched players Kioxia, Micron Technology, Samsung Electronics, and SK Hynix, to the production 200+ layer feat. The Chinese memory and NAND flash giant announced this memory back in August 2022 as the YMTC X3-9070, along with its new Xtacking 3.0 architecture—a proprietary method by which the company can reliably stack a large number of NAND flash layers. Micron Technology is ready with a 232-layer 3D NAND flash of its own, although it hasn't hit a production ramp, yet. This is an incredible feat considering that YMTC only got into this business in 2016, compared to the other players that each have over two decades of market presence.

YMTC's ramp to 232-layer closely follows its unexpected 2020 feat of a production-grade 128-layer 3D NAND, which was groundbreaking enough to win a supply contract with Apple, before losing it in October 2022, due to political reasons (not technological reasons). The Xtacking 3.0 architecture involves back side source connect (BSSC) for the memory cell wafer, which leads to simpler process and lower cost compared to Xtacking 2.0 (up to 128-layers, which had introduced nickel silicide (NiSi) instead of tungsten silicide (WSi) for better device performance and I/O speed for CMOS wafer. The original Xtacking architecture from YMTC, which it debuted back in 2016, with layer counts going up to 64-layer, relied on cost-effective wafer-to-wafer bonding. The YMTC 232-layer 3D NAND flash should find plenty of takers in the consumer electronics industry, spanning smartphones, consumer storage devices, TVs, and other appliances. The high layer-count has a direct impact on density, which can help designers lower costs by using fewer chips, or increase capacity.

——从已经释放出的信息来看，YMTC和sk、Samsung等企业貌似在向两个不同方向发展。YTMC的产品更注重于性价比以及简化制作工艺。前者可能跟其自身定位有关。后者应该与其难以取得更先进的西方制造装备有关。而日韩传统厂家在功耗、性能上的追求明显比长江存储更加执着。
——单论层数的话确实是世界一流水平，不过考虑到其他方面的指标，很难说谁是绝对领先。
——长江存储是有自己的制造部门的，但不清楚此产品是由自己加工还是外包代工，考虑到最近的制裁令，后者可能性更大。
——目前尚未有大规模投入市场的信息，这种东西可以后续观察观察市场响应。
——厂商的封测问题也比较严重，我不是内部人员不知道问题出在哪里。外界可以观察到的是，客户的产品妥善率非常低，使用过程中常常出现问题。
——作为一个企业而非实验室，长江研究突破和有产品卖出去是两个概念，这牛皮不妨以后再吹。而且128层nand作为日韩厂商2019年已经可以批量出货的技术，苹果到2022年才敢在3~5%的比例上应用长江的芯片到非旗舰产品中。