Dismantling: What is the advantage of DRAM produced by EUV process?

After months of long waiting, Samsung Electronics’ D1z DRAM using extreme ultraviolet (EUV) lithography is finally in mass production!

Earlier this year, Samsung Electronics announced what it claimed to be the industry’s first D1z DRAM using both Argon Fluoride Immersion Lithography (ArF-i) and EUV lithography, and TechInsights is excited to announce that we are targeting Samsung’s latest/most advanced The teardown analysis of the D1z DRAM has some “new discoveries” and confirms some details of the technology.

Samsung Electronics has developed D1z 8Gb DDR4, D1z 12Gb LPDDR5 and 16Gb LPDDR5 DRAM components, and claims to have higher performance; we found that the latter two (LPDDR5) components are used in Samsung’s Galaxy S21 5G series that just launched in January 2021 ( Including S21 5G, S21+ 5G and S21 Untra 5G) smartphones. The 12Gb LPDDR5 chip is used in the SM-G998B/DS 12GB RAM of the Galaxy S21 Ultra 5G, and the 16Gb LPDDR5 chip can be found in the 8GB RAM of the S21 5G and S21+ 5G.

In the D1z technology node part, Samsung’s D1z 12Gb LPDDR5 has a 15% increase in yield compared to the previous generation D1y 12Gb version, and the design rule (D/R) has been scaled down from (previous generation D1y process) 17.1nm to 15.7nm. The overall die size is also reduced, from 53.53mm2 (D1y) to 43.98mm2 (D1z), and the new generation of chips is about 18% smaller than the previous generation.

  Dismantling: What is the advantage of DRAM produced by EUV process?

Table 1: Comparison of Samsung D1y and D1z LPDDR5 chips at 8Gb, 12Gb and 16Gb.

Samsung Electronics’ 12Gb memory chip labeled K4L2E165YC uses the most advanced D1z technology combined with EUV lithography, while the 16Gb LPDDR DRAM chip labeled K4L6E165YB uses non-EUV technology. Samsung seems to have developed D1z LPDDR5 using both ArF-i and EUV lithography in SNLP (storage node landing pad)/BLP (bit line pad) at the same time, and now it is fully produced with EUV SNLP/BLP lithography D1z LPDDR5.

At the end of 2019, Samsung released 1 million module samples using D1x EUV lithography technology, and has now launched mass production (HVM) DRAM products using EUV lithography technology for the global DRAM industry and market. Samsung Electronics’ D1z chip is supposed to be manufactured at its second production line in Pyeongtaek, South Korea.

 Dismantling: What is the advantage of DRAM produced by EUV process?

Figure 1: Comparing Samsung’s DRAM cell BLP patterns: (a) version without EUV lithography, (b) version with EUV lithography.

In the process integration of D1z 12Gb LPDDR5 components, Samsung Electronics only uses EUV lithography technology on one layer of mask, and the critical dimension of single SNLP (on the memory cell array)/BLP (on the S/A sense amplifier circuit area) (CD/pitch) is about 40 nm, and the BLP linewidth in the S/A region is 13.5 nm.

Figure 1 shows a comparison of the S/A BLP patterns of Samsung’s D1z 16Gb LPDDR5 chip with ArF-i lithography (a) and its D1z 12Gb LPDDR5 chip with EUV lithography (b). By utilizing EUV lithography, the edge roughness (LER) of the BLP lines in the S/A region is improved, possibly reducing bridging/shorting defects.

Dismantling: What is the advantage of DRAM produced by EUV process?

Table 2: D1z DRAM head-to-head comparison: Micron D1z LPDDR4 vs. Samsung D1z LPDDR5.

Comparing the D1z competitor from Micron (Table 2), Samsung’s memory cell (0.00197μm2, Micron’s 0.00204μm2) and D/R (Samsung’s 15.7nm, Micron’s 15.9nm) are smaller. Micron’s D1z p products use ArF-i lithography at all mask steps and may not use EUV lithography for some time, including D1α and D1β.

 Dismantling: What is the advantage of DRAM produced by EUV process?

Figure 2: Samsung DRAM (from D3x to D1z) memory cell size trends.

Samsung’s DRAM memory cell size and D/R trend changes from D3x to D1z are shown in Figure 2 and Figure 3, respectively. DRAM memory cell and D/R scaling has become more and more difficult in recent years, but Samsung has shrunk the D/R of the D1z to 15.7nm, which is 8.2% less than the previous generation D1y.

Figure 3: Samsung DRAM (from D3x to D1z) design rule trends.

Samsung will continue to increase the number of mask layers using EUV lithography for next-generation DRAM products, such as D1a, which is expected to be mass-produced in 2021, and D1b, which is expected to be mass-produced in 2022.

The Links:   SKKD16216 LC171W03-C4K2

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