Willman made all eight of his free throw attempts as the Bison went 19 of 19 from the line on the way to their seventh straight win over Lafayette.
Top-seeded Bucknell (24-8) will host Lehigh on Wednesday at 7:30 p.m. in the Patriot League championship game. It will be the Bison's ninth title game appearance in the Patriot League's 22-year history.
Bucknell broke the game open with a 25-7 run over the final 10 minutes of the first half on its way to a 40-20 lead at the break. The Bison coasted in the second half and led by as many as 32 points.
Cameron Ayers added 12 points for the Bison.
Ryan Willen scored 11 points and Rob Delaney added 10 for the Leopards (13-18).