LAKE FOREST, ILL., AUG. 29 -- Mike Ditka will coach the Chicago Bears through 1990, the team announced today.

"He is indispensable to us chasing the Super Bowl," said Michael McCaskey, the team president.

Ditka already had signed for this season. His new contract won't make him the NFL's highest paid coach but "that doesn't matter," he said. "The opportunities in Chicago are second to no opportunity in the United States, in New York or Los Angeles or anywhere," he said.

He had asked for 3 percent of the Bears' stock as part of a new contract, but neither he nor McCaskey would say whether he will get it.

McCaskey and Ditka said they will sign the contract in a week or two. Ditka has argued with McCaskey about various subjects since becoming head coach in 1982 and had been rumored as a possible successor to Tom Landry at Dallas. But Ditka said today: "I intend to finish my coaching career here."

In his five seasons as Bears coach, his team are 54-25, including the three playoff victories in 1985 that led to the Super Bowl title. In the last three seasons, the Bears are 39-9 in the regular season.