The U.S. Supreme Court will hear a $290-million US dispute between Microsoft Corp. and Canadian technology company i4i Inc. over complaints that the former's ubiquitous Word program violates one of i4i's patents.

Loudon Owen, left, i4i chair, and founder Michel Vulpe first sued Microsoft for patent infringement in 2007. (Mark Blinch/Reuters)

The high court on Monday agreed to hear an appeal from the Redmond, Wash.-based Microsoft, which wants the multimillion-dollar judgment against it erased.

In its appeal, the world's largest software maker says the lower court that handles patent cases makes it too hard for those accused of infringement to argue that a patent should never have been granted initially. Tech giants Apple Inc. and Google Inc. have taken the unprecedented step of publicly backing their rival Microsoft in the dispute.

In Microsoft's appeal, Apple told the justices that the patent system “is tilting out of balance,” giving disproportionate power to people who secure patents of questionable legitimacy, Bloomberg reported.

Toronto-based i4i first sued Microsoft in 2007, saying it owned the technology behind the XML used in Microsoft Word. The technology in question gave Word 2003 and Word 2007 users an improved way to edit XML, which is computer code that tells the program how to interpret and display a document's contents.

The lower courts say Microsoft wilfully infringed on the patent, and ordered it to pay i4i $290 million US and stop selling versions of Word containing the infringing technology.

"The attack on patent holders and the adverse implications from the standard Microsoft is proposing is unprecedented and would deal a devastating blow to any U.S. patent holder, large or small," i4i chairman Loudon Owen said.

The ruling is the largest ever upheld by an appeals court in a patent case, but Microsoft has yet to pay any of the funds as it appeals the decision.

Microsoft now sells versions of Word that do not contain the technology in question. It's believed that more than 500 million people in the world use some version of the Microsoft Word software.

Microsoft executive David Howard said the company is glad the justices decided to hear their appeal.

The court’s decision to hear the case “is a clear affirmation that the issues raised in this case are critical to the integrity of our patent system,” he said. "We look forward to presenting our case to the Supreme Court."

Chief Justice John Roberts did not take part in the consideration or the decision in this case. He reported owning between as much as $250,000 US worth of Microsoft stock in 2009 on his annual disclosure report.

The court will hear the case in early 2011.