The five-time defending champion United States will play in its 20th gold-medal game on Tuesday against the winner of the other semifinal between Canada and Switzerland.
Carpenter put the U.S. in front early in the second with her third goal of the tournament. Carpenter got a stick on Lee Stecklein’s shot from the point to redirect it past goaltender Anni Keisala.
Murphy scored on a breakaway late in the second. Murphy took advantage of a turnover at the blue line and went backhand to forehand for a shot that trickled by Keisala.
“Megan Keller had a nice blast up the wall, and I was ready for it, I wanted it, so it felt good,” Murphy said after her second goal of the worlds.
Kendall Coyne Schofield added an empty-netter with 2:53 to go to seal the rematch of the 2019 final that the U.S. won 2-1 in a controversial finish.
Finland, which was outshot 33-14, had a good offensive opportunity midway through the first period with a two-man advantage for two minutes, but the United States did not allow a shot.
Finland emptied its net on a power play with 7:22 残り, but U.S. goalie Nicole Hensley kept it scoreless.
The Finns will look to claim their 13th bronze medal on Tuesday. The American will look to tie Canada with 10 gold medals.