Flip Chip Interconnection Structure Having Void-Free Fine Pitch and Method Thereof

摘要

A semiconductor device is made by providing a semiconductor die having a contact pad, forming a circular solder bump on the contact pad, providing a substrate having a trace line, disposing a non-circular solder resist opening over the trace line, placing the solder bump in proximity to the trace line, and reflowing the circular solder bump to metallurgically connect the circular solder bump to the trace line. The circular solder bump contacts less than an entire perimeter of the non-circular solder resist opening which creates one or more vents in areas where the circular solder bump is discontinuous with the non-circular solder resist opening. The non-circular solder resist opening can be a rectangle, triangle, ellipse, oval, star, and tear-drop. An underfill material is deposited under the first substrate. The underfill material penetrates through the vents to fill an area under the solder bump.