Micron, the U.S. company, shipped a prototype of 6th generation DRAM last month, becoming the first in the memory semiconductor industry to do so, while Micron's DRAM design and manufacturing process shows clear differences from Samsung Electronics and SK hynix. This is expected to be a crucial factor in determining the success or failure of the three companies during the upcoming mass production competition.
In the case of Micron, the company plans to minimize the use of advanced equipment such as extreme ultraviolet (EUV) lithography systems and maximize the use of existing mature processes with argon fluoride immersion (ArFi) lithography equipment to speed up mass production. While Micron is likely to have a faster production speed immediately, there are observations that the three companies may show differences in chip yield, productivity, and performance in the medium to long term.
According to the industry on the 10th, Micron's prototype of the 10-nanometer 6th generation (D1c) DRAM unveiled last month reportedly used EUV in some limited processes. A Micron representative noted, "In the case of EUV, the technical stability is still insufficient, so it was only used in processes that were really necessary," adding, "We determined that introducing it at this time was the right decision after reviewing the expense and productivity."
This illustrates clear differences from Samsung Electronics and SK hynix. Samsung Electronics, which was the first to introduce EUV equipment into the memory semiconductor production process, has been using EUV in its DRAM production process since 2020. For the 10-nanometer 3rd generation (1z) DRAM, EUV processes were applied to only one layer, and the number of layers utilizing EUV has been continuously increased since then. For the next-generation D1c DRAM, more than five EUV layers will be applied.
SK hynix also introduced EUV equipment into DRAM production starting in 2021, but the speed and application range have been approached more cautiously than Samsung Electronics. SK hynix applied EUV from the 10-nanometer 4th generation (D1a) DRAM, which reportedly used EUV technology on one layer. For the next-generation D1c DRAM, SK hynix is expected to use more than five EUV layers, similar to Samsung Electronics.
So far, Micron has been advancing advanced DRAM production without EUV. In the 10-nanometer 6th generation DRAM, which was shipped last month, Micron has also adopted a conservative approach, utilizing EUV processes on only one layer. However, the industry views that the ArFi lithography equipment, on which Micron relies for a significant portion of its production processes, inevitably leads to lower yields due to the increased number of process steps compared to using the more advanced EUV.
A semiconductor industry source stated, "Replacing one EUV layer with the existing ArFi equipment-based multi-patterning may not be an immediate challenge, but as the number of EUV layers increases over time, the difficulty gap will widen once it surpasses three layers," adding, "When mass production begins, the possibility is high that Samsung Electronics and SK hynix, which have stabilized the EUV process with years of experience in yield and production volume, will maintain an advantage."
Meanwhile, Samsung Electronics, which possesses the most EUV equipment (more than 30 units) among the three memory semiconductor companies, is reportedly embarking on extensive fine-tuning of the EUV process to recover from failures in the 10-nanometer 4th and 5th generation DRAMs. The company has put effort into research and development (R&D) of new resist materials, robust light sources, and advanced masks, with internal evaluations indicating progress in throughput and process efficiency.
In January, Samsung Electronics formed a dedicated task force (TF) to stabilize the EUV process, appointing Vice President Lee Sang-hoon, who previously worked at Intel and is noted as an expert in EUV technology with around 20 years of experience. A source familiar with Samsung Electronics stated, "Samsung Electronics is focusing on improving resist sensitivity and minimizing defects to create a cost-effective mass production system for EUV equipment," and added, "It appears that the company has established an optimal manufacturing step to some extent through years of trial and error."