Micron, the world's third-largest DRAM supplier, announced Monday (Aug. 28) that it has filed a lawsuit in the U.S. District Court in Delaware alleging that memory interface developer Rambus (Mountain View, Calif.) has violated federal antitrust laws. Micron also seeks to show the "invalidity, non-infringement and non-enforceability of Rambus patents pursuant to a number of different bases," according to a statement from Micron (Boise, Idaho). Neither Micron nor Rambus was available for comment by press time.

The lawsuit comes as Rambus is stepping up its pressure on DRAM companies to pay royalties for use of its patents on SDRAM and double-data-rate SDRAM, in addition to the royalties they already pay for Rambus DRAM. Rambus' aim, the company has stated, is to discourage DRAM makers from supporting SDRAM and double-data-rate SDRAM and to favor higher production of RDRAMs.

One company currently negotiating with Rambus is NEC Corp., which promotes RDRAMs for use in high-end systems, but whose DRAM revenue depends almost entirely on high-volume SDRAMs. NEC does not produce a significant volume of DDR SDRAMs, though its DRAM partner, Hitachi Ltd., is a staunch supporter of the latter technology. NEC and Hitachi will merge their DRAM operations next January.

An NEC spokesman here said the company began negotiating with Rambus several weeks ago. There's still no telling how the Micron antitrust suit will affect those talks, but NEC has taken a keen interest in the fight, he said.

"I think we and the rest of the industry will watch this very closely because the legal situation is very unclear," the spokesman said. "Clarification is what's really needed. Everyone wants to get on with their business of making memory."

The DRAM industry is now divided over Rambus' attempt to cast a wide net over DRAM patents. In June, Toshiba Corp. broke the ice by announcing it had signed a patent licensing agreement with Rambus covering SDRAM, DDR SDRAM, DDR fast-cycle RAM as well as controllers that directly interface with these memory types.

A week later, Hitachi cut a similar deal with Rambus that buried a legal dispute between the two companies stemming from Rambus' attempt to stop Hitachi and one of its customers, Sega Enterprises, from importing into the United States Hitachi-made SDRAMs and Sega's Dreamcast game consoles with SDRAM controllers.

As with Micron, Rambus has had a tough time getting Infineon Technologies AG to sign on to its licensing plan. After licensing negotiations fell through, Rambus recently filed a lawsuit against Infineon for patent violation.

The newest battle between Micron and Rambus is important because of the legal ramifications it could have on the semiconductor industry. Patent negotiations have been a fixture of the DRAM industry since its beginning, and DRAM companies usually end up signing cross-licensing agreements so that both companies can get on with manufacturing. Rambus, on the other hand, develops signaling technology used in DRAMs but does not make its own chips. Hence, its revenues depend entirely the payments of DRAM makers that use its technology.

Rambus' business model isn't unique, as companies such as ARM, Dolby and MIPS have made a business of licensing their intellectual property to the semiconductor industry. But Rambus' efforts are controversial because its technology was practically imposed on the industry in the early stages by its ally Intel Corp., and because of Rambus' recent efforts to apply sliding-scale licensing terms that would raise the cost of producing standard SDRAMs for DRAM makers.

This approach is in direct conflict with Micron's business strategy. Micron has a history of holding off on new technologies, preferring instead to push existing interfaces to the limit while squeezing out production costs. Even before SDRAM became prevalent, Micron had pushed for the industry to adopt a new version of the entrenched EDO memory, called burst EDO, before moving to SDRAM. The company's backing of DDR SDRAM, an extension of existing SDRAM signaling technology, is a continuation of that strategy.

As Micron's opposition to Rambus became more clear, Intel in 1998 invested $500 million in Micron to support the design and production of RDRAMs. At the time, Intel had backed RDRAM exclusively for use with its new chip sets, which have only started to appear this year. But Intel has since softened its stance in the face of RDRAM's low production volume and high costs, and its chip sets now back 133-MHz and DDR SDRAMs.

Even after Intel's investment and the introduction of Rambus-based chip sets, Micron has been among the slowest of the major DRAM companies to adopt RDRAM. According to the company's product guide, it is sampling a 144-Mbit RDRAM but has not determined when it will start production. The company plans to introduce samples of 288-Mbit RDRAM early next year, with production scheduled for the second quarter. NEC, by contrast, is gearing up for 288-Mbit RDRAM volume production this year.

Meanwhile, Micron is now sampling 64- and 128-Mbit DDR SDRAM, and will ramp volume production this quarter. A 256-Mbit DDR SDRAM is slated for introduction in the fourth quarter, and will move into volume production in early 2001.

Both Micron and Rambus are no strangers to legal fights when it comes to protecting their turf. A well-known denizen of the court system and the Federal Trade Commission, Micron since the 1980s has fought and often beat IC companies from Japan, South Korea, and most recently Taiwan over the dumping of memory chips in the United States.

Rambus too has shown it can be deft at enforcing its patents after it convinced Toshiba to sign on to its licensing strategy, then forced Hitachi to pay up and has since put Infineon on the defensive by filing a patent violation lawsuit.