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Hard Gold Plating Entire PCB Surface

From what I understand about hard gold plating, it is more difficult to do "select" plating unless it is an edge connector of a pc board. I have a requirement for hard gold plating of an area (for one component) in the center of my PCB and according to my PCB fabricator, this would be very difficult and expensive for them to do. Can hard gold plating be done easily as a finish for the entire board? Would it have an impact on SMT assembly?

Laurie Fraser
PCB Designer - Tewksbury, Massachusetts
May 8, 2009

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Laurie,
Sorry it took so long to answer this, I've been out of town for a few weeks without my laptop. "Deep well" Au plating has been in effect within the PCB industry for many years. After photo image, developing, touch up, pattern Cu plate, tin plate for etch resist, the original resist is stripped. A very light scotch brite scrub and good rinse will ensure good adhesion of the second "tent coating" of resist. The resist used for Ni-Au plate should be appropriate for that type of plating. The area to be selectively plated in Ni-Au is then imaged and developed. The board is then Ni and hard Au plated only on the secondary image developed. The board is then stripped of the resist and then etched. Like Tin, Gold is also an etch resist, so there is no chance of the copper beneath it being etched off the board. A reputable PCB shop can do this very easily. Whole board gold plating has also been done for years, if requirements call for it. Good Luck to you.

Mark Baker
Fellow Plater - Syracuse, NY, USA
June 25, 2009