Tony, There are several consideration that have to be taken into account with this type of process. First, because you are applying the dry film to a sever topography, you should be using a vacuum laminator to apply the dry film. Some companies apply the dry film with a HRL or CSL, but inevitably they have seepage of the solutions under the resist along the trace (soda straw effect). Second, the gold plating should be as efficient as possible to help with the success. Third, the thickness of the dry film should be greater than the plated circuit height. Most companies are using a 3 mil dry film for best success. We normally recommend our Laminar GA30 for this type of application. If you would like to have more information please give me a call. Ken Bridges - Dynachem >>> Tony King <[log in to unmask]> 02/19/97 01:49am >>> There are a variety of methods for application of electrolytic nickel/gold to printed circuit boards, most use a buss connection to the features which is removed at the routing or secondary drill operations. The buss can be internal or external however serves the same function. Some designs do not allow a buss type connection, it becomes necessary to use the base foil as the buss after pattern plate prior to etch. A selective gold application requires an additional coating of dry film photo resist to cover all but the features to be nickel/gold plated. The nickel/gold process is very aggressive on photo resist, causing film lifting and under plate of nickel/gold under the film. Does anyone in the manufacturing industry know of a photo resist capable to survive this process without lifting ? (double coat,image and develop) How are other manufacturers coping with nickel/gold application when buss connections are not an option ? Electroless nickel/gold is an even more aggressive process than the electrolytic process, is there a process to apply hard gold selectively to boards with the electroless process? What is used to mask the other portions of the board ? Tony King Elexsys International Inc. Nashua N.H. [log in to unmask] 603-886-0066 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************