摘要 |
A structure and a method of manufacturing a Pb-free Controlled Collapse Chip Connection (C4) with a Ball Limiting Metallurgy (BLM) structure for semiconductor chip packaging that reduce chip-level cracking during the Back End of Line (BEOL) processes of chip-join cool-down. An edge of the BLM structure that is subject to tensile stress during chip-join cool down is protected from undercut of a metal seed layer, caused by wet etch of the chip to remove metal layers from the chip's surface and solder reflow, by an electroplated barrier layer, which covers a corresponding edge of the metal seed layer.
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