By Dan Levine SAN FRANCISCO (Reuters) – Apple Inc has paid its leading outside law firm approximately $60 million to wage patent litigation against Samsung Electronics Co Ltd in a California federal court, according to Apple legal documents filed late on Thursday. Apple and Samsung are engaged in global litigation over each others intellectual property. The two mobile technology rivals have gone to trial twice in the last two years in a San Jose, California federal court, and juries have awarded Apple a total of roughly $930 million. In court filings, Apple asked U.S. District Judge Lucy Koh to order Samsung to pay $15.7 million of the total amount Apple has spent in legal fees.