ALEXANDRIA, Va., April 9 -- United States Patent no. 12,269,106, issued on April 8.
"Two-step solder-mask-defined design" was invented by Koustav Sinha (Boise, Idaho) and Hyunsuk Chun (Boise, Idaho).
According to the abstract* released by the U.S. Patent & Trademark Office: "An apparatus for a BGA package includes a pad mounted on a substrate. The apparatus also includes a solder resist layer disposed over the substrate and a buffer layer disposed over the solder resist layer. The solder resist layer can have a first aperture and the buffer layer can have a second aperture. The first and second apertures are aligned such that at least a portion of the pad is exposed to create a solder-mask-defined mounting pad. A diameter of the second ap...