From: [log in to unmask] Return-path: <[log in to unmask]> To: [log in to unmask] Subject: Re: [TN] Copper plating & Copper thickness Date: Wed, 11 Nov 1998 11:11:53 EST Mime-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7bit Les - Thanks for your excellent piece explaining in greater detail the factors affecting surface and hole copper plating. The boundary layer is also referred to in some circles as the diffusion layer. It should also be noted that impingement platers were a great idea but fell far short of expectations. The initial application of that technology was to gain higher current densities. We all know what's happened to hole sizes and board thicknesses over the years. Enter airless acid copper plating. Solution transfer through the holes is significantly enhanced if this kind of agitation is properly set up and employed. Thus, surface to hole plating thickness disparity is minimized. I'm currently working on technology that will go even further to promoting uniform copper distribution over the entire surface of the board, including in the holes. Why settle for getting a 1.0 mil minimum of copper in the hole and 1.5 or even 2.0 mils everywhere else, especially around the perimeter of the board? And at low durrent densities. Why not dispense with the border (and other thieving designs) and still achieve this? If you're interested, we should talk off line about it. Regards, Roger Mouton