| 摘要 |
A ball grid array device includes a substrate and a die attached to the substrate. The substrate further includes a first major surface and a second major surface. A first ball, having an attached end and a distal tip end, is attached to a major surface of the substrate. The first ball has a first height. A second ball, having an attached end and a distal tip end, is also attached to the major surface. The second ball has a second height different from the first height. The first height and the second height are selected to produce a substantially co-planar surface at the distal tip ends of the first ball and the second ball. The major surface is not substantially co-planar. A method for forming the balls of a ball grid array device on a major surface of a substrate includes determining height differences across the major surface of the substrate, placing lands on the substrate, and forming a plurality of balls on the lands. Each of the balls has an attached portion and a tip portion. The balls are formed with varying heights so the tip portions of each of the plurality of balls define a substantially planar surface.
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