Methods and apparatus for bump-on-trace chip packaging

摘要

Methods and apparatuses for a attaching a first substrate to a second substrate are provided. In some embodiments, a first substrate has a protective layer, such as a solder mask, around a die attach area, at which a second substrate is attached. A keep-out region (e.g., an area between the second substrate and the protective layer) is a region around the second substrate in which the protective layer is not formed or removed. The keep-out region is sized such that a sufficient gap exists between the second substrate and the protective layer to place an underfill between the first substrate and the second substrate while reducing or preventing voids and while allowing traces in the keep-out region to be covered by the underfill.

主权项

1. A device comprising:
a first substrate having traces formed thereon, the first substrate having a die attach region, a keep-out region around a periphery of the die attach region, and a periphery region around a periphery of the keep-out region, the first substrate having a protective layer overlying the traces in the periphery region, at least a first trace of the traces extending from the protective layer to the die attach region, at least a first trace of the traces extending from the protective layer to the die attach region; a second substrate electrically coupled to the first substrate in the die attach region; and an underfill interposed between the first substrate and the second substrate, the underfill extending over the traces located in the keep-out region; wherein an area of the keep-out region is between about 5% and about 18% of an area of the second substrate.