Semiconductor device and method of making the same

A method comprising:

• forming a redistribution structure comprising:
• forming a first conductive via in a first opening of a first masking structure,
• removing the first masking structure,
• forming a first dielectric layer covering the first conductive via,
• planarizing the first dielectric layer to expose an upper surface of the first conductive via, and
• forming a under-bump metallurgy comprising a first seed layer atop the upper surface of the first conductive via, wherein the first seed layer of the under-bump metallurgy completely covers a first interface between the under-bump metallurgy and the first conductive via;
• and
• bonding a module socket to the under-bump metallurgy of the redistribution structure.

A device comprising:

• a redistribution structure comprising:
• a conductive via extending through a dielectric layer to a first conductive line, wherein an upper surface of the conductive via is recessed from an upper surface of the dielectric layer, and wherein a difference in height between the upper surface of the conductive via and the upper surface of the dielectric layer is no greater than 0.15 microns, and
• an under-bump metallurgy comprising a seed layer atop the upper surface of the conductive via and the upper surface of the dielectric layer, wherein the seed layer completely covers an interface between the under-bump metallurgy and upper surface of the conductive via, the interface being free of voids;
• and
• a module socket connected to the under-bump metallurgy.