Rambus expands patent claims to DDR2 memory

Rambus broadened its legal battle against the memory industry on Tuesday, filing a patent lawsuit against certain manufacturers of chips based on the emerging DDR2 (double data rate 2) standard.

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Hynix Semiconductor, Nanya Technology, Inotera Memories and longtime Rambus foe Infineon Technologies AG were named in the suit, which was filed in the U.S. District Court for the Northern District of California on Tuesday.

Products from those companies that use the DDR2, GDDR2 (graphics DDR2), and GDDR3 standards infringe upon several Rambus patents, the company said in a court filing. Micron Technology, another major memory vendor, was not named in this complaint because of a court order in a separate case involving Micron and Rambus. That order forbids the companies from entering into further litigation, a Rambus spokeswoman said.

Rambus designs memory interfaces, the technology that links the memory chips to the rest of a system. The Los Altos, California, company believes that its patents for memory technology cover the DDR SDRAM (synchronous dynamic RAM) standard used in the vast majority of the world's PCs.

DDR2 and GDDR2 are evolutions of that standard that allow memory chips to run more reliably at speeds above 400MHz. They are expected to become mainstream memory technologies by the end of this year or the beginning of 2006.

In 2000, Rambus sued Infineon claiming that Infineon's memory chips infringed upon Rambus' patents. Infineon, Hynix, and Micron have all filed legal claims challenging the validity of Rambus' patent claims because the company failed to disclose it held or was seeking those patents while it was a member of a committee that developed the SDRAM standard.

In the original Infineon case, Rambus was convicted of fraud by a jury for failing to disclose the patents. But that verdict was overturned after an appeals court ruled that the policies of the Joint Electron Device Engineering Council (now known as JEDEC Solid State Technology Association) did not specifically require companies to disclose patents they held or were seeking. This cleared the way for Rambus to pursue its claims against the DRAM industry, and a second trial against Infineon is pending as claims against Micron and Hynix, which had been waiting for a resolution in the Infineon case, move forward.

Billions of dollars are at stake in the cases, as Rambus is seeking damages and royalties on all DDR SDRAM memory chips sold throughout the world. Samsung Semiconductor Inc., the world's leading DRAM manufacturer, has already signed a license for Rambus' technology, as have several other, smaller memory firms.

Last week a judge ruled in favor of Rambus in the Hynix case. That ruling states that Hynix infringed on several of Rambus' patents, but a trial in March will determine if Hynix's products infringe on all of Rambus' patents.

Rambus has also filed an antitrust lawsuit against Infineon, Hynix, Micron, and Siemens AG for allegedly colluding to drive up the price of Rambus' own memory standard, RDRAM, by holding back production of RDRAM chips in the late 1990s. A separate investigation by the U.S. Department of Justice into price-fixing among the DRAM vendors has resulted in guilty pleas from four Infineon executives and one Micron manager.