Technique for verifying the microstructure of lead-free interconnects in semiconductor assemblies

摘要

A method for verifying the internal microstructure of interconnects in flip-chip applications includes providing a microelectronic assembly comprising the following: a substrate hosting an array of flip-chip attach pads and one or more process control pads; a flip chip having an array of solder bumps in contact with the array of flip-chip attach pads; and one or more representative solder bumps contacting the one or more process control pads. The representative solder bumps have a substantially similar or identical chemical composition as the array of solder bumps. A reflow cycle is then applied to the microelectronic assembly to melt and solidify the array of solder bumps on the flip-chip attach pads and melt and solidify the representative solder bumps on the process control pads. The surface texture of the representative solder bumps is then optically inspected to determine an internal microstructure of the array of solder bumps.