Tillman, a second-round draft choice in 2003, could be with the Bears through the 2013 season. He has started 49 games in four seasons.
"They compromised. We compromised," Tillman said. "They were willing to listen. We were willing to listen. That's how it got done."
"I'm glad for Nate, proud of Nate for getting his deal done and glad mine has gotten done," Tillman said. "I think Nate and myself work well together."
The two have combined for 21 interceptions during the last two seasons, most by any cornerback tandem in the NFC.
"I'm sure Lance had a lot to do with us being a top defense," Tillman said, adding he didn't talk football specifics with Briggs, who isn't expected to be with the team when training camp opens this week.
"We'll miss him. I really will," Tillman said.