Wisconsin trailed by one goal two different times in the third period. Ty Emberson found the back of the net for a fourth time this year midway through the period to tie the game. The Nittany Lions answered back just two minutes later, retaking the lead when Tim Doherty scored his second goal of the game. But Caufield evened the game up with about five minutes left, beating Penn State goalie Oskar Autio.
Caufield now has an NCAA-leading 27 goals, while Linus Weissbach picked up his 28th assist of the season.
Wisconsin goalie Robbie Beydoun got the win by stopping 43 of the 46 shots he faced.
The Badgers, who won the Big Ten regular season title, will face Michigan or Minnesota in the championship game, as they try to win their second tournament title.