October 2013 – The Memory Guy Blog

Hynix Recovery – Not so Soon?

During SK hynix’ October 29 earnings call the company further clarified the status of its Wuxi fab line that was hit by a fire on September 4. In brief, the company may miss its expected end-November date to recover to full operation.

Interestingly, although DRAM bit shipments declined by 2% because of the fire, revenues increased by 3% thanks to price increases caused by the resulting tight DRAM supply. This gave the company a revenue boost taking total semiconductor revenues from ₩3.93 trillion ($3.54B US) in the second quarter to ₩4.08 trillion ($3.66B US) in the third quarter. Not only was this revenue a record number for SK hynix, but margins also reached a record high.

All in all, it was a very good quarter, despite the fire, and perhaps because of it.

The company disclosed that restoration of the air ventilation system and the clean room have been Continue reading “Hynix Recovery – Not so Soon?”

What is a 3D NAND?

In the prior post we discussed the need to go vertically into the body of the die, since NAND flash can not be scaled much farther in length and width on the die’s surface. Toshiba invented a 3D NAND which has been adopted and refined by all flash makers. The idea is simple: Rather than shrink the cell’s length and width, why not turn the NAND string so that it’s standing on its end?

This concept is illustrated by this post’s first graphic, which was provided by Applied Materials. (Click on the graphic to see the whole thing at a larger size.) A standard NAND string that normally runs longitudinally is turned on its end to become a vertical string. Not only that, but it makes things easier if the string is split into two sections and Continue reading “What is a 3D NAND?”

Why Facebook Can’t Get its Dream Memory Chip

During the Flash Memory Summit last August Facebook’s Jason Taylor, Director of Capacity Engineering and Analysis, asked in his keynote speech for a flash chip with dramatically lower cost per gigabyte, saying that he would readily give up speed and endurance to achieve this lower cost. Taylor called this “Cold Flash” and said he was willing to use something that was “Write Once, Read Many” or WORM for data that was unlikely to change over its lifetime. He said this was Facebook’s “Ask of the Industry.”

That same sentiment was echoed yesterday at Samsung’s Memory Solutions Forum by eBay’s Distinguished Engineer and Technologist Roark Hilomen, who said that he could live with 1/3rd the number of writes that normal flash supports as long as he could get it for 1/4 the price.

Unfortunately this is simply not possible.

Let’s do a little math to understand Continue reading “Why Facebook Can’t Get its Dream Memory Chip”

Why Do We Need 3D NAND?

A memory chip of a certain area costs about the same amount to produce, no matter how many bits it holds. Naturally, the more bits you can cram onto this chip, the cheaper the price per bit will be. Low cost is of the utmost importance in the world of memory.

Memory chip makers have shrunk the cost of a bit some nine orders of magnitude since the 1960s largely by shrinking the process, or “scaling” to increasingly tighter process geometries.

Flash has always been expected to reach a scaling limit. Over the past few generations technologists have developed Continue reading “Why Do We Need 3D NAND?”

Hynix Squeaks Out Another Update

In its own uniquely minimalistic style, Hynix has updated the status of the second line of its Wuxi fab, the one that was hit by a fire on September 4:

We would like to provide the following update on the recovery status of SK Hynix Wuxi fab that was affected by the fire on Wednesday September 4, 2013. The air ventilation system and cleanroom in the line that was affected by the fire have now been substantially restored, and we have resumed partial utilization in this line from Thursday October 10, 2013. We will gradually raise utilization and make every effort to recover normalized level of pre-fire utilization in November as planned.

This statement should put to rest Continue reading “Hynix Squeaks Out Another Update”

What is 3D NAND? Why do we need it? How do they make it?

In August 2013 Samsung announced its V-NAND, the first production 3D NAND, kicking off a big change in the way that NAND flash will be manufactured. This new technology raises a number of important questions:

What exactly is a 3D NAND?
Why does the industry need to go to a 3D topology?
How the heck do they make such a product?

To answer these questions I assembled a series of articles posted as weekly segments on The Memory Guy blog during the fourth quarter of 2013. The different sections are listed below, with hot links to each section.

Each of these is a topic that is complex enough to warrant its own post, so for the nine Fridays I published a post to explain each one in depth. I hope you find it engaging and informative.