Thus, Micron has announced the first shipments of DDR4 RAM units manufactured in its node 1 Alpha; This new memory, which the company is building before implementing EUV for its manufacture, will offer a very interesting improvement in bit density, as well as improvements in terms of power consumption. And the most curious thing about this is that all these improvements come just when all manufacturers are immersed in the manufacturing processes of DDR5, which could mean a significant decrease in prices in DDR4 RAM.
Micron already makes the densest and most efficient DDR4 RAM
Initially 1 Alpha will be used only to make DDR4 and LPDDR4 memory; Over time, Micron hopes to expand its use to other products, yes. The company claims a bit density improvement of up to 40% over products built at its current manufacturing node (1z), and power consumption is said to have improved by up to 20%.
“The large improvement in 1 Alpha’s density is driven by a combination of improved process technology and manufacturing matrix efficiencies due to design improvements.”, – said Thy Tran, vice president of DRAM process integration at Micron. “The efficiency of the die alone gave us about a 10% design improvement.”
We usually talk about node fabrication in numerical terms: 3nm, 5nm, 7nm, 20nm, etc. but these conventions refer to the way TSMC, Samsung, and Intel number their various nodes. Because all node names are arbitrary, different companies may use different standards and it gets very confusing about it.
Memory makers, by contrast, opted to move away from direct numbering once they moved away from 20nm flat silicon and opted for metrics like 1X, 1Y, and 1Z. According to Blocks and Files, 1X was roughly at 17-19 nm manufacturing, 1Y was equivalent to 14-16 nm, and 1Z was equivalent to 11-13 nm. The same site notes that 1Z manufacturing accounted for 15% of Micron’s DRAM bit production in Q3 2020.
Micron does not yet use EUV lithography
What’s impressive is that Micron is moving to make these chips still without using EUV; extreme ultraviolet lithography is a manufacturing method that uses much smaller wavelengths (of UV light) to etch wafers, unlike 192nm ArF lasers that power DUV (deep ultra violet).
EUV has made its way into the industry by leaps and bounds, but it is still not widely used for DRAM production. Samsung uses EUV for its own 1Z manufacturing, but spends less of its own production in percentage terms than Micron (6% vs. 15%). Micron, however, is a much smaller company in terms of market share.
In the past, Micron has hinted that it could wait up to 1β or even 1γ (1 Beta and 1 Gamma respectively) to introduce EUV. The company has previously said that it would move to EUV only when it would be beneficial, and has posted slides implying that the switch date could be 2023 or even later.
According to Tran, Micron incorporated new materials, tools and “novel techniques” to improve its multi-pattern alignment. The downside to not using EUV is that this increases the need for multiple patterns, which allow 193nm lithography to target smaller sizes than would otherwise be possible even through immersion lithography, but it also has trade-offs. in terms of quality.
Micron may be delaying its transition to EUV due to the limited number of tools manufactured each year, or because it found alternative ways to improve manufacturing performance. In the long term, all leading edge manufacturers will move to EUV, but Micron may be the last to do so based on their roadmaps.