Micron Delays Sample Shipments of 3D NAND Flash Memory Chips

The move is an apparent break with earlier plans to have 3D NAND samples available in Q1 (CED Sept 17 p3) as the industry starts to replace 2D planar technology. Samsung began production last year of 128-Gbit 3D chips using 24 cell layers and SanDisk is planning to begin producing in volume in 2016 (CED May 30 p3). Micron expects to start ramping 3D NAND production in the second half and has said the technology will require 32-34 cell layers to be competitive with 2D planar.

The 3D NAND technology requires a new controller, dry-etch deposition and new inspection tools and, while it promises to lower costs, the increased performance of CE products will make designs more complicated, Micron has said. Despite not yet shipping 3D NAND samples, Micron is satisfied “its relative competitive position and where we are relative to what hear others might be,” Duncan said. “Putting a bunch of non-enabled components out in the market place right now for our competitors to see is of limited value,” Duncan said. “I think we want to wait till a little bit closer to where we think those system level solutions are enabled."

Micron has forecast a “fairly slow transition” to 3D NAND and solid-state drives (SSDs) will be among the first targets for the technology, analysts have said. Micron also “invested a lot in quality” for SSD technology for the broader market, Micron has said. The company is qualifying with OEM customers 20-nanometer M500 SSD products that are expected to ship in the second half. Under its own Crucial brand, Micron will deliver M550 devices in volume in Q3, President Mark Adams said. The enterprise SSD segment will provide “some strong growth,” helping offset overall “softness” in NAND, he said.

Percentage-wise, Micron’s NAND production is expected to decline by high-single digits in fiscal Q3, a sharp change from a 35 percent increase in the previous quarter, with SSDs partly to blame. Though SSDs require a “larger cycle time,” they will post a “much higher performance” in fiscal Q3, Duncan said. While SSDs were a minuscule portion of Micron’s NAND production is fiscal Q2, they could approach half the output in some future quarters, Duncan said.

Micron also is moving its NAND production to a 16-nanometer process, which is being used initially in consumer memory cards, USB sticks and embedded products, Adams said. “These transitions in our manufacturing output will enable a lower-cost product mix in the future,” especially with 16-nanometer yields being “very good” so far, he said. The bulk of Micron’s NAND manufacturing will be with the 20-nanometer process, which accounted for 60 percent of fiscal Q2 production, Duncan said. Micron will “keep moving slightly” to 20-nanometer manufacturing in fiscal Q3, he said.

The company also gained a “major customer qualification” in fiscal Q2 for its graphics double-data rate version 5 (GDDR5) SDRAM technology and has seen “positive yield improvement” with the 25-nanometer process used to make it, Adams said. Micron didn’t identify the customer. Micron also landed a “major” design win with a CE manufacturer that will use its new input/output (I/O) controllers for TVs, Adams said. Micron also got “validation” of its “DDR4” products with “key chipset partners,” and is starting to ramp production. The DDR4 chips are expected to ship in May, Micron said.

Micron is buying the remaining outstanding shares it doesn’t own of Taiwan’s Rexchip and now controls all but 0.5 percent of them, Duncan said. Micron is paying $145 million for the remaining shares and Rexchip has been renamed Micron Memory Taiwan, Duncan said. Micron increased its stake in Rexchip in purchasing Elpida, which owned 65 percent of Rexchip, for $2 billion last year. Micron also bought Power Chip Technology’s 24 percent stake in Rexchip.