News from Japan: Mirai out-sims Monte Carlo

Feb. 17, 2009: Scanning headlines from Japan this week: the Mirai project’s blazing SRAM simulations; Toshiba and Fujitsu’s HDD handoff, Renesas’ rebellious union; and what might be the next fullerene.

Mirai vaults SRAM sim over the “brick wall”

Japan’s Mirai project (Millennium Research for Advanced Information Technology) and software firm Jedat say they have devised a simulation tool that predicts SRAM chip operation much faster than conventional methods, without requiring prototypes and paving the way to better yields, notes the Nikkei Business Daily.

Three years ago Mirai launched a “Robust Design of Transistor” project to figure out manufacturing processes and design structures that overcome the “Red Brick Wall” of transistor variability, which increases as circuit dimensions are scaled down and is a limiting factor in system chip integration. Part of their work involved evaluating variability in such robust transistors, using a “test element group” (TEG) on a 200mm wafer with 65nm-based SRAMs; measuring characteristics of each transistor determined normal distribution of variation, which could then be plotted independently by chipmaker and manufacturing technology used.

Combining these data and the information about the actual SRAM structure, Mirai came up with a method to precisely simulate a 256kbit SRAM’s operations, predicting the chip’s behavior to the degree of the chip’s actual measurements. But the simulation was “extremely time-consuming,” the paper notes.

Enter Jedet, which says it can accelerate the process through a proprietary method called “sample screening through boundary learning,” which reduces the amount of data needing to be processed. The result is a SRAM simulation tool that generates results 600× faster than the conventional Monte Carlo method of semiconductor device simulation. For designers, this means they will be able to use the TEGs, not fabricated SRAM prototypes, to analyze transistor variability and predict SRAM operations, and correct design flaws at the process development stage, thus resulting in better yields once chips are manufactured.

Toshiba buying Fujitsu’s HDD ops

Toshiba is said to be purchasing Fujitsu’s hard-disk drive operation; neither firm indicated a monetary value for the transaction that is slated to close by the June quarter, but reports suggest a pricetag of ¥30B-¥40B (US ~$330M-$430M).

Under proposed terms, Toshiba will take a ~80% stake in the entity, which comes with production facilities in Thailand and the Philippines, and should absorb it entirely as a wholly owned unit within a year or two, notes Japan’s Nikkei daily.

For Toshiba, the move boosts its production footprint and lowers procurement costs for items such as magnetic heads and disks, the paper notes. The company also will utilize Fujitsu’s high-speed data read/write technology for its solid-state drives, an area in which it projects sales surpassing ¥100B/year by fiscal 2010. Fujitsu’s strong position in servers offers inroads here too, the paper notes. Overall, the Toshiba+Fujitsu HDD operation will command about 20% market share (they ranked 4th and 6th, respectively, according to data cited by the paper).

For Fujitsu, the deal (and a simultaneous sale of magnetic disk production to Showa Denko) spells the end of its magnetic head production and hard-drive related hardware. It will take a ¥30B writedown for the sale to Toshiba (split evenly between facilities/assets and personnel, the Japanese paper notes), pushing net losses to roughly ¥50B for the fiscal year ending in March, vs. a ¥48B profit in the previous fiscal year.

Renesas breaking union ranks?

A rebellious move from Renesas Technology’s labor union concerning springtime “shunto” pay negotiations could have reverberations across other unions and industries across Japan, according to the Nikkei daily.

Renesas workers won’t join the Electrical Electronic & Information Union’s unified demand for a >¥4500 monthly wage hike, the paper reports. The chipmaker is projected to lose about ¥200B (US ~$2.18B) in the current fiscal year.

The 8000-strong Renesas union is a core member of the influential industrial trade union umbrella group, the paper notes — thus, others including Oki Electric’s union are seen likely to follow suit.

The move is uncommon but not unprecedented, particularly in these times. Similarly, Mitsubishi Motors Corp.’s union won’t demand a payscale raise, in opposition to the Confederation of Japan Automobile Workers’ Unions stance on springtime wage negotiations.

Cheaper, flexible organic memory via inkjet

Nissan Chemical Industries and Kyushu U. have codeveloped a process to fabricate organic memory devices from inkjet printing, with application seen in smart tags, reports the Nikkei Business Daily.

The material is a polystyrene-gold dust combination of nanoparticles deposited by inkjet onto a substrate “sandwiched” between Al thin-film electrodes. Data stored as “on” and “off” states are variably set by exposing the material to different voltages; three 5V pulses sets it to a low-resistance state, while a >10V pulse sets it to a high-resistance “off” state. The gold particles make contact with the branched ends of the polystyrene resin’s molecular structure, enabling stable resistance value so the device can function as nonvolatile memory and retain data. The devices when fabricated are said to cost a tenth of that of silicon memory, the paper notes.

Only 2500b/cm2 is achievable now, but Nissan Chemical aims to improve this before market readiness, seen in fiscal 2010. The bendable devices can be printed onto films such as food wrapping, conceivably recording information to aid delivery and traceability. The company also wants to add an antenna to make a contactless smart tag akin to an RFID device that can be controlled with radio signals to read/write data from an external unit.

Nippon Mining strips FPD film biz

Seeing no demand rebound on the horizon and thus no profitability, Nippon Mining & Metals says it will exit the market for chip-on-film substrates for flat-panel televisions sometime this year, according to the Nikkei daily.

For about five years the company has produced and shipped samples of a double-layer copper foil laminate on plastic film upon which can be mounted semiconductor devices. But demand has slumped in step with sales of flat-panel TVs as well as prices for the materials.

A new carbon substance?

Reseachers at Tohoku U. say they’ve discovered via computer simulation a brand-new substance made entirely of carbon atoms, joining well-known structures like fullerenes and carbon nanotubes. Results are published in the current issue of Physical Review Letters.

The new substance, a three-dimensional structure comprised of rings of 10 carbon atoms, is similar to that of a geometrically proposed structure called a “K4” crystal; Evaluations by supercomputers using “first principles calculations” method show the structure’s metallic properties should conduct electricity. Prof. Tadafumi Adschiri et al. are currently testing synthesis of the substance; their work is sponsored by the Japan Science and Technology Agency.

The list of substances made solely of carbon is a short one: diamond, graphite, amorphous carbon, and more recently fullerenes and carbon nanotubes. The new substance has a 3D crystal structure like diamond, and is the first to also have metallic properties. A group led by Tadafumi Adschiri, a professor of chemical engineering, has begun testing synthesis of the substance. (It’s worth noting that the fullerene, too, led a hypothetical mathematical existence until it was proven to exist in nature as the C60 molecule.)


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