<p>➀ The chip industry is striving to increase the stack height of 3D NAND flash memory from 200 layers to 800 layers or more in the coming years to meet the endless demand for various types of memory.</p><p>➁ The additional layers will bring new reliability issues and a series of incremental reliability challenges, but the NAND flash memory industry has been steadily increasing the stack height over the past decade.</p><p>➂ The development direction of 3D NAND is from 500 to 1,000 layers. However, achieving so many layers is not just a matter of doing more of what we have been doing.</p>