| 摘要 |
A method and apparatus of attaching solder balls for semiconductor packages is disclosed herein. In a first embodiment, a stencil, having a hole array that matches with a solder ball array on a substrate, is fitted into stencil holder which is inserted the housing of the attachment apparatus. A prefluxed molded substrate strip is inserted into the main station directly above the stencil in the holder. A multiplicity of preformed solder balls are rolled from a reservoir across the stencil hole array thereby filling each of the holes. Vacuum may be used with a modified stencil design to assist in drawing the balls in the holes. An operator or pattern recognition camera may be employed to detect any missing solder balls where corrective action can be immediately taken. After the solder balls have been properly positioned relative to the substrate strip, the solder may be reflowed to attach the balls to the substrate. The described apparatus is relative inexpensive and flexible enough to accommodate various substrate sizes and types of packages.
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