I missed this when it came out a couple of months ago.
Can YMTC Really Win 8% of 2021’s NAND Flash Market?
Jim Handy Posted on May 12, 2020
A couple of weeks ago NAND flash start-up YMTC announced the production release of its 128-layer 1.33 terabit QLC NAND flash chip. According to a DigiTimes article about the chip the company plans to claim a share of 8% of the global NAND flash market in 2021.
A number of my clients asked The Memory Guy about this, since YMTC doesn’t yet seem to be a factor in the market. In fact, a sample of YMTC’s 64-layer chip, which the company’s announcement last September said was in mass production, wasn’t found by reverse engineering firm TechInsights‘ army of chip hunters until just a couple of weeks before the announcement of YMTC’s 128-layer chip. My clients’ questions centered on whether there was even a remote possibility that YMTC could actually ship 8% of the world’s flash in 2021. The short answer is: “Yes, but it’s a stretch.”
Some simple math can explain this. First of all, what will be the size of the 2021 NAND flash market? As long as demand is unaffected by teh COVID-19 pandemic then annual consumption should grow to about 690 exabytes. YMTC’s 8% of that would be 55 exabytes.
We know that YMTC’s new fab (pictured above), located in Wuhan, is designed to process 100,000 wafers per month. This is about the same size as other NAND flash fabs, and is the size of plant that makes the most economic sense. I haven’t yet heard that this fab is operational, so it would need to be ramped to full volume production by the end of this year to make the math work in my example below. For now YMTC’s flash is being made at XMC, a successful foundry, founded in 2006, that is now owned by YMTC.
What can you do with 100,000 wafers a month? Let’s first analyze this based on YMTC’s new 128-layer 1.33Tb QLC chip. If we can guess at the die size of that chip then we can estimate how many gigabytes each wafer can produce.
YMTC’s 1.33Tb QLC chip is probably just a 1Tb TLC design that’s using QLC instead, since 1.33Tb is exactly 4/3 of 1Tb. Furthermore, let’s assume that the die size of a YMTC 128-layer 1Tb TLC chip is almost the same as the die size of the 64-layer 512Gb TLC YMTC chip that TechInsights recently analyzed. That’s twice as many gigabits in twice as many layers. The information that TechInsights shares in their flyer allows us to calculate that the 64-layer part’s die size is about 116mm². Objective Analysis has a die/wafer calculator that tells us that a maximum of 533 of these chips would fit onto a 300mm wafer, yielding 89 terabytes/wafer (533 chips x 1.33Tb – or 0.166TB – per chip).
Our 55 exabytes, then, would require a total of (55 x 1,024 x 1,024)/89 = 648,000 wafers, or 54,000 wafers/month. Of course, this is at 100% yield. Production yields for NAND flash are more typically in the high 90% range for a mature product, so a few more wafers would really be needed, depending on YMTC’s yield. This 54,000 number is the lowest number of wafers that would be required to supply 8% of the market.
At the other extreme (using the same math), if YMTC wanted to make its 8% goal using only the 64-layer 512Gb TLC part that TechInsights analyzed it would take 144,000 wafers per month to achieve that goal. Clearly this won’t work using a fab that can produce only 100,000 wafers/month. It’s most likely that YMTC plans to use a mix of these two parts and will still be ramping the fab in 2021, both of which will make the 8% goal a challenge.
continues at thememoryguy.com |
