Searching for Nonlinearity: Scaling Limits in NAND Flash

Data generation is growing at an exponential rate and the market opportunity for data storage is vast. However, there is still a substantial difference in the amount of data created versus data stored, driven by price elasticity of demand in the storage media. Pricing lies in the balance of supply and demand, but for NAND manufacturers to be profitable, cost is the driver for consistent price decline and will ultimately determine the amount of data stored. In this talk, we show that as NAND Flash moves into a mature era of 3D scaling using only increasing layer count results in a sub-linear cost reduction while producing higher bit growth. This breaks the virtuous cycle of growth, producing more bits than the market can absorb at a given price point and challenges the affordability of future investments. NAND scaling needs to move away from solely increasing layer count and instead seeking new avenues for reducing cost and complexity. Equipment productivity and reduction in consumables remain critical focus areas for the supply chain to contribute to cost reduction. Wafer bonding technology can be an enabler for new opportunities. It allows for decoupling the memory array from complex logic circuits, allowing new high speed logic integration with the memory layers, and simplifying manufacturing cycle times. This technology also allows the industry to move away from a one-size-fits-all NAND die to customized solutions for various applications and system level savings. Despite such breakthroughs, ultimately the health of the storage industry will be determined by fair distribution of the profit pool across the value chain commensurate with the R&D and capital spending by the different players.