Former WorldCom chief Bernard Ebbers (search), convicted last month of orchestrating the $11 billion accounting fraud that sank the company, is asking for a new trial, citing unfair rulings by the judge.

In papers made public Monday, lawyers for Ebbers said the judge should have granted immunity to three former WorldCom Inc. (search) executives who were reluctant to testify — but who the defense claims could have helped prove Ebbers' innocence.

Lawyers for Ebbers also said the trial judge unfairly told jurors they could find him guilty based on "conscious avoidance," which they said allowed jurors to convict Ebbers because he "should have known" about the fraud.

And they claimed Ebbers should have been allowed to present a defense that the way WorldCom counted its revenue complied with generally accepted accounting principles.

"These errors seriously compromised the fairness of the trial," the lawyers said in court papers dated Friday.

Ebbers was convicted in March of conspiracy, securities fraud and filing seven false reports with the Securities and Exchange Commission (search). At 63, he could spend the rest of his life in prison.

Ebbers, who took the witness stand in his own defense, claimed all along that the fraud was the brainchild of chief financial officer Scott Sullivan, and that Sullivan kept him in the dark.

Sullivan, who has pleaded guilty in the case, testified that he warned Ebbers repeatedly that the only way WorldCom could meet Wall Street estimates would be to cook the books. He said Ebbers ordered him to "hit the numbers."

The new-trial request was sent to U.S. District Judge Barbara Jones, who presided over the trial. If the motion fails, Ebbers could still take his case to a federal appeals court.

Sentencing for Ebbers is set for June.