Korea will play Canada in the bronze medal game in Alberta province.
Swiss skip Mirjam Ott said the win in front of 3,000 fans was "crazy" after reaching her first world final. Both teams led at various points.
"That was a really crazy game - up and down," she said. "We were lucky that we won. We know that errors can happen in that kind of game.
"We just knew we had to believe in our teams and fight and fight. I wasn’t nervous at the beginning, I just didn’t perform, but my team kept fighting and gave me great support.”
Korean skip Ji-Sun Kim accepted the blame for the defeat after a poor ninth end.
"It is very disappointing not to be playing for gold. But it is only my second experience at this level and I’m proud to be at this level," she said. "We played OK, but I made a mistake in the ninth end with my take-out.
“I don’t know yet how we’ll play against Canada - but I will do my best to win bronze.”
Ott, a twice Olympic silver medallist, added that she expects an exciting final on Sunday.
"It will be a good game against Sweden. We’ll have to play good curling, they’re a really strong team," she said.
"We’ve lost twice against them although it was really close, but right now we’re just lucky to be in the final.
"I won’t be thinking too much about gold, I’ll just be thinking about curling. It’s just great to be playing my first final in the worlds in Canada, it’s just awesome.”