A week ago, after eliminating the perennial champion Montreal Canadiens and whipping the Philadelphia Flyers here in the first game of the semifinals, the Minnesota North Stars were dreaming of a bath in champagne overflowing from the Stanley Cup.

The impossible dream, however, proved impossible and it ended tonight, four games later. The Flyers' fourth straight success was a 7-3 rout that earned Philadelphia a rest until at least Tuesday, before the Flyers make their first appearance in the final since 1976.

"You can always dream that you can do it, but you can't be disappointed if you battle and work as long as you can," Minnesota Coach Glen Sonmor said. "We were beaten by a better team that knows how to win, the best team in hockey all year long. I see no reason why they won't go on and prevail in the finals, too."

The Flyers certainly offer no weak spots to either Buffalo or to the New York Islanders. They won tonight with speed and muscle, plus a fair share of the weird bounces.

Bill Barber scored twice, once on a shot that struck a Minnesota defender and changed direction, the second time when Mike Busnik's drive from the point struck his skate and slid in.That gave Barber nine goals for the series, tying teammate Reg Leach's Stanley Cup record of 1976.

Barber's first goal came with Philadelphia shorthanded and that set another mark: three shorthanded scores in a series. It also matched Derek Sanderson's 1969 standard of three in a playoff year.

Leach scored a pair, also, one on a centering pass from behind the Minnesota net that hit defender Craig Hartsburg and caromed back across the line.

"I guess they got the bounces," Somnor said, "but they force you and force you, and when you create so many chances, the puck will bounce for you."

Hartsburg gave the North Stars a 1-0 lead after just 44 seconds but by the close of the first period the Flyers had built a 4-2 lead. Not surprisingly, none of their goals came with both teams at full strength.

Rick McLeish and Leach converted power plays, the Flyers' only extra-man opportunities of the night except for a 14-second advantage late in the second period. But it was Barber's shorthanded goal, only 10 seconds after Philadelphia's first penalty of the game, that sent the Flyers ahead to stay.

The foul, to Norm Barnes for a trip away from the puck, was so ludicrous that it almost seemed the Flyers sought the manpower disadvantage. And who could blame them?

In the last four games, the North Stars managed only two goals in 35 power plays. For the series, the Flyers clicked on eight of 18. During the regular season, the North Stars ranked ninth, the Flyers 21st and last.

"Our specialty teams did a good job for us all year, but they (the Flyers) don't let you play," Sonmor said. "They shut off our power play completely and they scored those shorthanded goals. I was surprised by the efficiency of their power play, because our penalty killers were among the best in the league."

Gary Edwards, the Minnesota goalie, was on his knees trying to regain possession of his lost stick when a Bob Daily blast struck the stick and caromed into the net for a 4-2 Flyer lead.

Gilles Meloche replaced the shaky Edwards in goal at the start of the second period, but the outcome was already determined. Only a score by rookie Rob Flockhart, in his first playoff game, kept Minnesota from a zero over the last 40 minutes.

Flockhart also dared to punch Bob Clarke, which brought Flyer enforcer Paul Holmgren circling the officials to attack him. Holmgren escaped the obvious third-man ejection call, prompting Sonmor to walk out on the ice at periods end to berate referee Wally Harris.

"Clarke, despite the feeling here, is not God," Sonmor said. "He's allowed to be hit like anybody else."

Barber, smiling under a media assault that topped any North Star surveillance, said he was enjoying the playoffs, even more than the championship years of 1974 and 1975.