A U.S. appeals court will likely be asked to revisit recent patent rulings involving Rambus, an attorney for the chip maker said at a court hearing on Friday.

Much of Rambus' income has come from patent litigation against companies it accuses of not paying for its technology. Winning its legal battles would make it easier to negotiate additional licensing arrangements with other companies.

Last month, the U.S. Court of Appeals for the Federal Circuit found Rambus was wrong to shred hundreds of boxes of documents relevant in two patent infringement lawsuits it filed, sending its shares down 18 percent in one day.

In one of two parallel rulings, the U.S. appeals court found Rambus destroyed documents related to a patent suit in which it had won a judgment of $350 million plus interest against South Korea's Hynix Semiconductor. The appeals court asked U.S. District Judge Ronald Whyte in San Jose, Calif. to review his ruling in view of the document destruction.

But on Friday Whyte said the companies could still ask the Federal Circuit to revisit its recent decisions, and he held off on setting a schedule for the Hynix case, and another action against Micron.

How long that process is going to take is anybody's guess, Whyte said.

Rambus attorney Greg Stone told Whyte that it was likely requests for rehearing would be filed with the Federal Circuit.

The hearing came days before jury selection is scheduled to begin in a separate antitrust trial, in which Rambus is seeking over $4.3 billion in damages from Micron and Hynix.

Rambus settled antitrust claims with Samsung in January 2010 in a deal that could bring in $900 million.

In the other Federal Circuit ruling, the appeals court said it was clear Rambus had destroyed documents but it was not clear the action was so serious that a Delaware court should have tossed out its suit brought against Micron.

It sent that dismissal back to the U.S. District Court in Delaware, adding that the lower court might still decide the shredding was serious enough for Rambus to lose the case against Micron, the top U.S. maker of memory chips for computers.

The case in U.S. District Court, Northern District of California is Hynix Semiconductor et al. v. Rambus, 00-20905.

(Reporting by Dan Levine; Editing by Phil Berlowitz)

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