Hynix picks ISi’s ZRAM for DRAMs

August 13, 2007 – Hynix Semiconductor Inc. will use Innovative Silicon Inc.’s (ISi) ZRAM high-density memory IP for its ZRAM chips, the first company to license the ZRAM technology for DRAMs. The “eight-figure deal” gives Hynix the right to use the technology to build memories, with royalties upon production. The two firms also will work together and “invest significant engineering resources” to extend Z-RAM into DRAM-based process technology, ensuring manufacturability in extraordinarily high volumes that is also cost-effective in the competitive DRAM market.

ISi’s zero-capacitor floating-body “ZRAM” technology is based on a standard silicon-on-insulator (SOI) logic process with a similar one-transistor bit-cell, that the company says is faster and 1.5-2.0x denser than DRAM with similar power, and requires no exotic process changes unlike DRAM or other novel memory technologies. For DRAMs, the smaller bitcells translate into smaller, cheaper die — and eliminating the need to form capacitors translates to faster work integration and node migration, simplified manufacturing flow, and thus lower capital/manufacturing costs and reduced WIP and “at-risk” wafers.

With standalone DRAMs being so sensitive to costs, this deal to use ZRAM suggests that Hynix has determined costs are equal or cheaper to go with SOI vs. forming capacitor structures, despite the significant increased cost of SOI wafers vs. bulk silicon. A Hynix spokesperson told WaferNEWS that the company is currently “at the early stage of looking for possibilities and practicality of ZRAM technology” with production plans to be determined “after assessing its marketability,” and claiming that at this early stage “we cannot compare or assess exact production cost.” But the spokesperson added that “if using SOI wafers becomes a trend in the semiconductor industry, we expect its cost to be gradually reduced and ZRAM technology will gain more merits.”

An ISi spokesperson explained that because the capacitor accounts for 20%-30% of the cost of the process, removing the capacitor altogether results in significant savings. And the simple single-transistor bitcell is much easier to scale to smaller processing nodes, each of which can save 30% from the node before it. The company showed data culled from analysts plotting DRAM cost reduction slowing from a 26%/year historical average to 19%/year, and with DRAM bits/PC surging 40%+/year now — suggesting that falling behind the Moore’s Law curve can add up to $200 to the memory cost in the average PC.

An upgraded “Gen2” version of ZRAM released in Dec. 2006 allows more charge to be stored with a greater programming window, with different trade-offs between speed, power, and density depending upon the application. AMD is using the Gen2 ZRAM for its microprocessors.

“Z-RAM promises to provide an elegant approach to manufacture dense DRAMs on nanometer processes,” according to Sung-Joo Hong, VP of Hynix’s R&D division, in a statement, adding that the chipmaker could end up creating “a new platform of products based on ISi’s innovation.”

Mark-Eric Jones, ISi CEO, explained in a statement that “memory chips built using ISi’s Z-RAM technology will be much smaller and cheaper to manufacture,” and will offer tremendous performance and usability advantages to end-users.” — J.M.


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