Rambus's quest to recover royalties from other chip manufacturers has been dealt a blow by the dismissal of its patent case against Infineon Technologies on allegations of legal misconduct.

Judge Robert Payne of the US District Court for the Eastern District of Virginia has granted Infineon's request for dismissal of the case. This is the second time Judge Payne has dismissed Rambus' claims that Infineon is infringing upon Rambus patents with its SDRAM (synchronous dynamic RAM) chips. The first time was in 2001, but that decision was later overturned by an appeals court.

Rambus believes that Infineon and other DRAM companies are using its patented technology in their SDRAM chips, which can be found in almost all of the world's PCs and servers. The DRAM companies contend that Rambus improperly influenced a standards-setting organisation to adopt technology for which Rambus held patents, but Rambus argues that the disclosure policies of that organisation did not require notification of current patents or patent applications.

In 2001, Infineon convinced Judge Payne to dismiss Rambus' patent infringement claims, and a jury found Rambus guilty of fraud for deceiving the DRAM industry. However, those rulings were overturned by a split decision of the US Court of Appeals for the Federal Circuit in 2002, which agreed with Rambus' version of events and sent the case back to Judge Payne for retrial on the patent infringement claims.

Judge Payne has now granted an Infineon motion for dismissal that was filed in December citing "litigation misconduct".

"Infineon is pleased that the court has found that Rambus' egregious conduct, including shredding key documents, failing to produce evidence, and testifying falsely under oath, constituted unclean hands and spoliation and was so improper as to warrant the dismissal of all of Rambus' remaining patent claims in this case. We are gratified that the court determined that Rambus' litigation misconduct should not be rewarded," Infineon said in a statement.

The judge's position was presented orally. A copy of the decision is not yet available, according to an Infineon spokesman.

"We look forward to eventually presenting our patent claims on the merits so our contributions to the industry and the value of our inventions are clear. In the meantime, we feel we have a strong case on appeal," said John Danforth, senior vice president and general counsel at Rambus.

Rambus is involved in other lawsuits against companies such as Hynix Semiconductor. In January, a judge in Northern California ruled that Hynix's chips infringed upon some of Rambus' patents. A trial was scheduled to begin later this month to decide the validity of other patent claims brought by Rambus in that case.

Rambus has also sued several DRAM companies alleging they conspired to hold down production of RDRAM (Rambus DRAM) in the late 1990s in order to inflate the prices of RDRAM chips. That case has gained steam as executives at Infineon and Micron Technology have pleaded guilty to charges of price-fixing brought by the US Department of Justice.