When designing the complex boards that many electronic devices require to operate, designers should consider manufacturability at every step. This is my last article focused on designing for the always-evolving manufacturing reality.

The previous installment focused on the solder mask and legend process. The last phase of production involves applying surface finish to protect copper from oxidation and facilitate soldering components onto the board. Choosing the right surface finish has always been important. If you are creating intricate designs with a wide variety of components, like for an ultra-high density interconnect (UHDI) board, surface finish is a critical last step.

Surface finish for UHDI boards requires extreme flatness and high solderability for fine-pitch components. Applying surface finish to the solder pads can affect solderability during assembly to a limited extent, but today’s surface finishes are designed with solderability in mind and are necessary to sustain the productive life of the board.