Ball attaching apparatus for correcting warpage of substrate and method of attaching solder balls using the same

A method of attaching solder balls using a ball attaching apparatus comprising:

• an indexer having a material thereon where the material has the ball lands and mold caps positioned at intervals between the ball lands;
• a movable holder located above the indexer;
• an attachment plate installed on a lower surface of the holder, the attachment plate comprising:
• projections formed at the positions corresponding to the placement of the mold caps on the material;
• and
• grooves formed with openings at the lower surface of the attachment placte at positions corresponding to a plurality of ball lands of the material,
• wherein each groove is capable of accommodating all or a part of a solder ball, and
• wherein each groove is formed with one or more holes with openings at the upper surface of the attachment plate;
• and
• eject pins, each of which is arranged through the hole of a groove toward the inside of the groove of the attachment plate for conveying and dropping solder balls on the ball lands, the method comprising the steps of:
• placing the material on the indexer, the material having a plurality of ball lands and the mold caps placed at intervals with respect to the ball lands;
• lowering the holder by which the projections formed on the attachment plate are brought into contact with the mold caps of the material until the warpage of the material is sufficiently corrected by pressing the mold caps;
• and
• attaching the solder balls to the ball lands on the material by removing vacuum in the eject pins.