Method of locating conductive spheres utilizing screen and hopper of solder balls

A method for placing an array of conductive spheres on prefluxed bond pads of a substrate, said method comprising:

• providing a substrate having a surface with a first pattern of bond pads;
• providing a stencil plate having upper and lower surfaces with a second pattern of through-holes therethrough, said second pattern of through-holes corresponding to said first pattern of bond pads;
• providing a shuttle plate having upper and lower surfaces with a third pattern of through-holes therethrough, said third pattern of through-holes corresponding to said second pattern of through-holes;
• providing a sphere reservoir adjacent the upper surface of said shuttle plate with an open top and configured to receive, hold and dispense conductive spheres into the third pattern of through-holes of said shuttle plate;
• placing said stencil plate over said substrate to align said first and second patterns;
• moving said shuttle plate across the upper surface of said stencil plate between a position aligned with said second pattern of through-holes and a position non-aligned with said second pattern beyond said second pattern of through-holes to drop conductive spheres through said second and third pattern of through-holes onto said bond pads;
• and
• removing said substrate from adjacent said stencil plate.