Vertical Channel Filled Metal 3D NAND Flash One of the key issues in the development of vertical stacking over 64 layers, the Atomic Layer Deposition (ALD) process can be formed in large areas in a high aspect ratio vertical channel Film, and has a good step coverage (Step Coverage), it applies to more layers of 3D NAND Flash vertical channel filler metal, but its deposition rate is slow and the higher the cost of materials and other issues.
ALD chemical vapor deposition (CVD), and another CVD technology plasma-assisted chemical vapor deposition (Plasma-Enhanced CVD; PECVD) compared to ALD using sequential injection of the first and second Precursor as a reactive gas to vaporize the film, which is different from the PECVD using plasma evaporation technology, while evaporation of two or more precursors for chemical reaction. ms3348-8-10
The advantage of ALD is that the film thickness can be accurately controlled and a large area uniform film can be formed at the atomic level precision, and it is suitable for depositing a thin film with excellent step coverage in the concavo-convex structure. On the other hand, PECVD is not easy in the concave-convex structure or the deep hole pattern Reaching the same thickness of the film, it ALD process is expected to become more than 64 layers of 3D NAND Flash vertical channel filler metal solution.
However, the deposition rate of ALD is slower than that of PECVD because of the long process time, and the amount of precursor needed by ALD is high, which makes the deposition cost increase. ms-470n
3D NAND Flash to 64 layers above the development of the need to improve the deposition and etching of thin film deposition, vertical through channels, channel filling metal and other processes, of which, film deposition process time, vertical through the channel need to change the cost of dry etching Technology, and channel filling metal ALD process required for the process time and cost increases and other issues, so how to cope with rising costs will become the 3D NAND Flash technology to develop more layers of important issues.
