Microsoft Corp asked the U.S. Supreme Court on Friday to reconsider a lower court's ruling that upheld rival i4i's patent related to text manipulation technology.
Microsoft filed a writ of certiorari with the court, effectively asking it to look for errors in the lower court's ruling and then toss it out.
This issue will not benefit from further percolating in the circuit courts, Microsoft said in its appeal.
The U.S. Patent and Trademark Office upheld the validity of the i4i patent in April, about three years after the legal fight began.
A federal jury awarded i4i $290 million last August after finding that Redmond, Washington-based Microsoft had infringed the i4i patent relating to text manipulation software in the 2003 and 2007 versions of Word, Microsoft's word processing application.
Microsoft has said that i4i's patent is invalid but that it has since removed the contested features from its current software.
Toronto-based i4i said it had been expecting the appeal from Microsoft, and is awaiting word from the Supreme Court.
We continue to be confident that i4i will prevail, i4i Chairman Loudon Owen said in a statement.
(Reporting by Ernest Scheyder; Editing by Richard Chang)