Method and apparatus for placing solder balls on a substrate

An apparatus for placing spheres at predetermined positions on a substrate, the apparatus comprising:

• a platform to support the substrate at a first sphere placement position in the apparatus;
• a placement station disposed above the platform that places spheres at locations on the substrate, the placement station including:
• a first container having a chamber to contain spheres;
• a first carrier tray having a substantially horizontal upper surface that forms a lower surface of the chamber and having a bottom surface, the upper surface having a first section and a second section, the second section having a plurality of holes formed therein to receive spheres, the first carrier tray being movable to position the second section between a fill position beneath the first container and a place position disposed over the first sphere placement position;
• wherein the placement station is constructed and arranged to fill the plurality of holes with spheres when the second section is in the fill position;
• to allow the spheres to pass through the holes, entering from the upper surface of the first carrier tray and exiting via the bottom surface of the first carrier tray;
• and to place the spheres at the predetermined positions on the substrate when the second section is in the place position;
• wherein the placement station further includes:
• a second container having a chamber to contain spheres;
• a second carrier tray having a substantially horizontal upper surface that forms a lower surface of the chamber of the second container, the upper surface having a first section and a second section, the second section having a plurality of holes formed therein to receive spheres, the second carrier tray being movable to position the second section between a fill position beneath the second container and the place position;
• wherein the placement station is constructed and arranged to fill the plurality of holes in the second carrier tray with spheres when the second section of the second carrier tray is in the fill position, and place the spheres at the predetermined positions on the substrate when the second section of the second carrier tray is in the place position.