Samsung has applied molybdenum (Mo) to its 9th generation V-NAND metal wiring process. This is the first attempt by a memory company, and it is evaluated that Samsung Electronics has once again started the ‘technology gap’.
Molybdenum is one of the next-generation metal wiring materials. Apart from the Samsung Electronics, companies such as SK Hynix, Micron, and Kioxia are also considering using molybdenum. Existing tungsten hexafluoride (WF6) suppliers are expected to decline, while molybdenum suppliers are expected to rise.
Samsung Electronics uses molybdenum in the 9th generation V-NAND metal wiring process. For this purpose, it introduced 5 units of Lam Research molybdenum deposition equipment. It is reported that approximately 20 more units of equipment will be introduced next year. Unlike the tungsten hexafluoride used in the existing NAND process, the molybdenum precursor is a solid. Since it is a solid, it is known that a high temperature of 600℃ must be applied for sublimation. For this, separate deposition equipment is required.
An official familiar with Samsung Electronics’ affairs explained, “In Samsung Electronics’ 9th generation V-NAND process, there are applications that use tungsten and applications that use molybdenum.” He added, “Molybdenum is used instead of tungsten in the oxide-nitride-oxide (ONO) structure.”
The reason Samsung Electronics applied molybdenum is to improve the ‘resistance’ in the transistor. If the resistivity is improved, NAND can be stacked higher. A materials industry insider said, “We have reached the limit of the height that can be reduced through tungsten,” and “If we use molybdenum, we can reduce it by 30-40%.” Another insider explained, “When using molybdenum, there is an advantage in that latency can be improved.”
An official from the materials industry said, “The price of molybdenum precursor is about 10 times that of tungsten hexafluoride,” and “The domestic tungsten hexafluoride market size is about 100 billion won per month, and if molybdenum precursors are commercialized, the market will grow to several times its current size.” He added, “This is why domestic materials companies are risking their lives developing molybdenum precursors.” Molybdenum precursors are deposited by sublimating a solid, but it has been reported that domestic companies are having difficulties because they have little experience handling solid precursors.
Another industry insider said, “The industry is discussing the application of molybdenum precursors to DRAM, non-memory, etc. in addition to NAND,” and “Micron also tested the application of molybdenum to 1gamma (γ) DRAM, although it fell through.”
A Samsung Electronics official avoided giving a direct answer to the question of applying molybdenum to the 9th generation V-NAND, saying, “It is difficult to answer about the technology roadmap.”
Samsung Electronics is also considering applying various new technologies, including cryo etching, to the development of next-generation NAND. Cryo etching is a process that utilizes TEL’s cryo etching equipment. Unlike the existing etching process (which is performed at 0℃ to 30℃), it is characterized by the etching process being performed at -70℃ based on the chiller temperature. It has the advantage of increasing the NAND channel hole etching speed by more than three times.
Meanwhile, SK Hynix is also preparing to apply molybdenum to NAND. At ‘Semicon Korea 2024’ in January, SK Hynix Vice President Kim Chun-hwan explained, “Currently, tungsten (as a storage gate material) is showing limitations in resistance,” and “Research on molybdenum as a substitute for tungsten is actively being conducted.” He added, “We will decide whether to adopt (molybdenum) technology in the 400-level after considering process maturity, productivity, and production cost.”
![Samsung applied molybdenum (Mo)](https://www.samnews24.com/wp-content/uploads/2024/07/Samsung-applied-molybdenum-Mo-.png)