Yesterday The Memory Guy learned of an amazing article in DigiTimes about a 3-6 week shutdown at Toshiba’s Yokkaichi NAND flash fab line. According to the story Toshiba’s production was shut down for 3-6 weeks accounting for a production loss of 100,000 wafers. Another article in PC Games N converted that to lost bytes and came up with the number 400,000 terabytes.
Some quick math shows the errors in both of these articles.
First of all, the wafer stoppage. The Toshiba/SanDisk Yokkaichi Joint Venture wafer fabrication complex processes a little over 2 million wafers per year. Divide that by 52 weeks and you find that’s about 40,000 wafers per week, so 100,000 wafers would be 2.5 weeks’ output, not 3-6 weeks.
The number of bytes that PC Games N published takes a little more math. According to TechInsights Toshiba’s 15nm 128Gb MLC chip has an area of 99mm². That gets you a little over 10TB/wafer. The company’s 48-layer TLC 256Gb part should produce about twice that. Yet, if you divide PC Games’ 400,000TB by 100,000 wafers you get only 4TB/wafer.
But, most importantly, if one of the leading NAND flash fabs, accounting for just under 40% of the industry’s production capacity, were shut down during a dire shortage for 3-6 weeks, wouldn’t you imagine that somebody would have noticed well before the shutdown had ended?
And would SanDisk/Western Digital be able to hide something like that from their investors without any threat of a shareholder lawsuit?
This just proves that certain events must be looked at with a critical eye, which is something that the analysts at my firm, Objective Analysis, do quickly, easily, and clearly. We thank our clients for their appreciation of this fact. We welcome others to engage with us for help in clearing the clutter caused by reports like this one.