3D NAND，如何演进？

Core Insights - The introduction of NAND flash memory has fundamentally transformed data storage and retrieval since the late 1980s, with applications spanning from smartphones to data centers [1] - The semiconductor industry is competing to increase NAND flash memory density while reducing cost per bit, transitioning from 2D to 3D NAND technology to overcome traditional size limitations [1][7] - Significant advancements include the shift from floating gate transistors to charge trap cells, which enhance read/write performance and allow for higher storage density [1][3] Group 1: Technological Advancements - The semiconductor industry is exploring new technologies to tightly pack storage cells both horizontally and vertically, with imec developing innovations like air gap integration and charge trap layer separation [2] - The GAA (Gate-All-Around) architecture is being applied in 3D NAND flash memory, allowing for vertical stacking of storage cells and improved density [3][7] - Current mainstream manufacturers are producing 3D NAND flash chips with over 300 layers, with expectations to reach 1000 layers by 2030, equating to approximately 100 Gbit/mm² storage capacity [7] Group 2: Challenges and Solutions - Maintaining uniformity in wire diameter across stacked layers poses challenges, increasing process complexity and costs [7] - Companies are investing in tools to enhance 3D NAND storage density, including increasing bit counts per cell and reducing GAA cell spacing [9] - The introduction of air gaps between adjacent word lines is a potential solution to reduce cell interference, with imec proposing a precise integration method [13][17] Group 3: Future Directions - The integration of air gaps and charge trap layer separation is seen as crucial for achieving future z-axis scaling in 3D NAND flash memory [24] - imec is developing new technologies for controlled charge trap cutting, which could enhance the storage window and prevent charge migration [20][24] - Innovative architectures are being considered to maintain leadership in memory development beyond 2030, driven by demands from cloud computing and artificial intelligence applications [24]