Chris Edwards: February 2010 Archives

shang-yi-chiang.jpgAt the company’s executive forum held in Yokohama, Japan, TSMC’s senior vice president of R&D, Shang-yi Chiang, provided some background on why yield problems surfaced on the 40nm process — and also some indications that 28nm will not exactly be plain sailing.

Chiang pointed to the shift to immersion lithography — a choice that Intel delayed by a generation — and the use of a new low-k dielectric in the metal layers as the main culprits for the foundry’s problems. He claimed that defect density has reduced significantly since the middle of last year, when chairman Morris Chang decided to expand the team working on 40nm at TSMC.

Chiang said the move from 90nm to 65nm was comparatively simple and the relative cost quite low. “Moving to 45 and 40nm is a lot more challenging,” he said. “This is the first time we began to use 193nm immersion [lithography]. This means the photoresist during exposure is submerged in water and [presents] a very high potential defect [density].”

The low-k dielectric, with a dielectric constant 2.5, was also more fragile than its predecessor. It seems that 40nm was a partial rerun of the 130nm introduction when chipmakers discovered that soft dielectrics and packaging machinery are not the best of mates — the pressure needed to seal the package crushed the metal interconnect.

If you had something like an 80 per cent market share and one of the factors in that was a proprietary language, would you open up the language knowing that this would help competitors turn a foothold into a stronger position? No, I probably wouldn’t either.

But there comes a point where the proprietary language becomes a problem to the customers because it makes it harder to use stuff that has been developed outside that environment. And the customers have to choose between migrating or sticking with what they know and reinventing stuff that they know exists elsewhere. If those customers migrate, then the dominant company loses the reason for holding on to that language - it becomes more of a millstone than an advantage.

In the case of custom and analogue design, the language in question is Cadence Design Systems’ Skill. It’s grown like topsy over the years to the point that even people who’ve worked at Cadence aren’t quite sure what’s in it. Those outside the company don’t stand a chance. But a scripting language like Skill is crucial not only to general custom layout, as it prevents analogue engineers from quietly going mad repeatedly drawing the same shapes over and over again. It also forms the basis of things like process design kits (PDKs) that the foundries provide, as it allows them to define how cells and components are laid out.

IC Insights has posted its estimates for capital spending by the top ten chipmakers this year as companies open up their wallets in expectation of cashing in on very tight supply through the rest of the year and into 2011.

The analyst firm expects the top ten to increase their spending by 67 per cent in 2010, a bigger jump than that expected for the entire industry. That is also set for a sudden leap in spending, up by 51 per cent, but it’s an indicator of how the big fab owners are gradually pulling away from the rest of the pack in terms of fab spending. Only the biggest can afford to operator fabs while the rest are forced to rely increasingly on foundry production.

Taiwanese foundry TSMC’s estimated spend this year is expected to surge by almost 80 per cent, “spurred on by the challenge from the upstart GlobalFoundries”, writes IC Insights president Bill McClean.

UMC has increased its own outlay dramatically but is already a long way behind TSMC and won’t even match GlobalFoundries this year following the incorporation of Chartered Semiconductor Manufacturing into the Abu Dhabi-financed foundry.

TSMC may only be $200m behind Samsung’s $5bn in terms of 2010 spending. Intel is predicted to pay out around $4.9bn for fab equipment this year and is easily the most conservative spender. However, the company didn’t cut back heavily last year when everyone else was taking an axe to their capital-expenditure budget. The company has a lot of its 32nm capacity in place ready for the launch of the Westmere generation of processors. And there is no point in contributing to a glut of processors when supplies of everything else will be tight.

The top trio alone — Intel, Samsung and TSMC — will account for 38 per cent of all capital spending in the semiconductor business this year. And more than half of the outlay from the top ten, which will represent two-thirds of the total spend.


Although these numbers are big, they won’t have much of an effect on 2010 chip supplies, McClean said at the recent IC Insights seminar in London. Although fab owners are now more efficient at getting tools up and running on the clean-room floor, it still takes several quarters for them to be productive. And the fab-equipment makers have to be able to service the sudden leap in demand having slashed their workforce once again in a sudden semiconductor slump.

However, the big fab owners will have an advantage in ordering: they have cash in the bank. Smaller players, such as the cash-strapped Taiwanese DRAM makers, will probably find themselves at the back of the queue for kit as credit will be in short supply.

Xilinx will for the first time use the same foundry as its main competitor to make its next generation of programmable logic devices and expects to have parts built on a 28nm process by the end of the year.

Xilinx has nominated Taiwanese foundry TSMC as one of the two suppliers it plans to use to make field-programmable gate arrays (FPGAs) on the upcoming 28nm process – which is expected to double density compared to the current 45/40nm-based parts.

Historically, Xilinx has used the world’s second largest foundry UMC as its silicon supplier. Although the FPGA maker has turned to a number of foundries since the 130nm generation, including IBM, Samsung and Toshiba, the company has up to now avoided using TSMC.

Chuck Tralka, senior director for product definition at Xilinx, said when the company looked at how it would move on from the 45nm generation, “we began a survey of process nodes. Originally, we looked at 32nm and then moving to 28nm.”

The company then decided to move straight to 28nm, opting for variants of a high-k, metal-gate process that trade some performance for lower static power consumption, which increases with the number of transistors on a die.

“As we looked out at the process vendors. We began with a survey of what we expect to become available from the various foundries. We began looking with an eye to managing the performance issues. We talked to each of the potential foundry partners,” said Tralka.

“We determined that TSMC and Samsung had the right technology available. We worked with TSMC two years ago and started running test vehicles and began aligning process parameters with internal simulations. We expect to have devices available by the end of the year.

“We are working with both partners: one of them is in the lead,” said Tralka, but declined to say which foundry is likely to have products ready first.

“Both processes are actually fairly similar. They are both high-k, metal-gate and they have similar power/performance characteristics. We work to try to align the processes as much as possible. There are some differences. The families will get tweaked as we prepare to map one for each process or another.”

“What we will be doing is mapping particular families into particular fabs. And aligning what we think are the best power-performance trade-offs.”

Tralka claimed the long-standing relationship between Altera and TSMC “is not that big a concern. It is something that we have thought about. But TSMC does a good job working closely with each of their partners without compromising the work of their partners.

“Our foundry has been a multi-foundry strategy. We are a larger company company and we need more capacity available to us. And our strategy has been to choose the best partners for each node rather than wedding ourselves to a single process partner,” Tralka explained. “It’s possible that we will make different choices in future generations.”

In Dresden and Munich, the receivers in charge of Infineon's erstwhile memory subsidiary Qimonda are flogging off the remaining fab equipment and office furniture that haven't found homes at companies such as Texas Instruments.

However, Infineon has not sold some of the soft assets, such as patents that were filed under the German chipmaker's stewardship. And the company seems to be following the Rodime plan to getting some of its investment back: sue the people still in the DRAM business for infringment. I assume it will stop short of getting into the sports-betting business. However, before it bought Littlewoods' betting operation, Rodime managed to extract a tidy sum in licensing fees from various big disk-drive makers after the Scottish company shut its own manufacturing plant.

Infineon said it filed a complaint with the US International Trade Commission against Elpida, pushing for an exclusion order that will prevent the Japanese memory maker from importing its memory devices into the US even though Infineon no longer sells anything that competes.

So far, the complaint hasn't received a docket number from the ITC, and the organisation has not said that it will investigate the complaint. Infineon has claimed Elpida infringed four of its patents when making the DRAMs it currently ships.

At the IP conference a couple of years ago, Mike McLean of technology-analyst Semiconductor Insights predicted a rise in complaints by companies armed with large patent portfolios. But acknowledged there are issues with suing competitors when the litigation may affect customers of both parties.

“The companies may not be the most popular in the world,” McLean noted. “Are you willing to license [patents] where there are pre-existing business relationships. Do you risk damaging that relationship? Is there a willingness to litigate?”

Jack Browne, then president and CEO of MIPS Technologies, put it more starkly: “You do have to be prepared for thermonuclear warfare when you decide to go to litigation.”

As companies get bounced out of markets in which they used to compete aggressively, more will be tempted to pursue the Rodime option and use the patent collection they built up. As chipmaking involves a complex web of IP, no-one will be immune to the potential of patent suits. And, because those companies have left the market, the threat of mutually assured destruction will not bring the traditional solution: a big bag of cross-licensed patents.

DRAM and flash-memory maker Micron Technology has swooped on Numonyx, the joint venture between Intel, STMicroelectronics and private-equity firm Francisco Partners in a deal worth $1.27bn in what may be a series of acquisitions in the resurgent but cash-strapped memory business.

Micron will pay using shares – there is no cash in this deal. "We are not leveraging the balance sheet to do this acquisition," boasted Micron CEO Steve Appleton in a conference call with analysts last night, shortly after all the parties to the deal managed to reach an agreement. Appleton apologised for the lateness of the call but said he wanted to get the news out as quickly as possible. "It is a really solid way to add to the company in a variety of ways."

The next generation of FPGAs from Altera won't be quite as programmable as the last - although you will be able to flip some of the logic inside them as they run. For the generation of FPGAs to be made on a 28nm process, Altera is making several changes.

One change is the merging of HardCopy - the mask-programmed gate array used to provide fixed versions of customer design for less money per die - with the mainstream programmable logic family of Stratix parts. Another is the decision to finally adopt partial reconfiguration so that parts of the logic can be switched in and out while the rest of the system is still running.

"Partial reconfiguration has been around for a long time," said David Greenfield, senior director of Altera's HardCopy business unit. "But this is a fairly significant shift for Altera."