SanDisk to begin making 'X4' flash chips

SanDisk is disclosing at a San Francisco technology conference Tuesday that it will begin mass production of memory chips that will allow consumers to store up to 64GB of data on tiny flash cards. SanDisk X4 memory chip packs in four bits per cell(Credit: SanDisk) The Milpitas, Calif., company's X4 technology will pack four bits of data into each memory cell. To date, flash memory chipmakers typically stored one bit or two bits per cell. SanDisk--the largest supplier of retail flash cards--is making the disclosure jointly with Toshiba at the 2009 International Solid State Circuits Conference (ISSCC). The two companies will use 43-nanometer manufacturing process technology to make the chips. X4 technology, which SanDisk got when it purchased M-Systems in 2006, will yield tiny Secure Digital (SD) flash cards that hold 64GB of data. Currently, mainstream SanDisk SD cards top out at 16GB, though pricey 32GB cards are also on the market. "It is a 64-gigabit single die (chip), which is 8GB (per die), the highest capacity point in the industry," said Khandker Quader, senior vice president, memory technology & product development, SanDisk, in a phone interview Monday. In addition to the memory chip, the die also includes an X4 controller--which manages the data flow. The memory and controller "will be sold as an integrated solution," Quader said. Controllers are the secret sauce used by flash card and solid-state drive suppliers to boost performance. The importance of controllers increases as flash chip densities increase because higher densities require increasingly sophisticated controllers to deliver the necessary performance. The memory technology itself--the 4 bits per cell 64-gigabit memory--is co-developed and co-owned by SanDisk and Toshiba. The X4 controller technology is solely owned by SanDisk, Quader said. SanDisk and Toshiba also have joint manufacturing facilities in Japan. The advancement is important because NAND flash--like all silicon chasing Moore's Law--is facing challenges to increase densities "even at two bits and three bits per cell," he said. (NAND is the type of memory used in flash cards and solid-state drives.) A SanDisk paper at the ISSCC will discuss the performance of the X4 technology. Data speeds will hit 7.8 megabytes per second, Quader said. "This is comparable to what others are producing at lower bits per cell," he said. X4 flash cards will be available commercially in the first half of 2009, according to Quader. SanDisk will also present a paper on 32-nanometer X3 technology--three bits per cell--for use in thumbnail-size microSD cards (even smaller than SD cards) that boast capacities up to 16GB. X3 will also be used in solid-state drives, SanDisk said. Despite these advancements, SanDisk is still a laggard in the emerging solid-state drive market, where companies like Samsung, Toshiba, Micron Technology, and Intel are the early leaders. SanDisk announced at CES in January that it would deliver a 240GB SSD by mid-year.