... the result of a hot drill melting the epoxy resin and spreading it across the hole wall during its up and down motion. The | MULTILAYER BOARDS PROTOTYPING | epoxy smear causes poor and in some cases non electrical continuity to the innerlayers as well as poor adhesion of the plated copper to the | MULTILAYER BOARDS PROTOTYPING | hole wall. In desmear, the chemical attack is designed to remove only the surface smear of resin from the hole wall, without attacking the wall | MULTILAYER BOARDS PROTOTYPING | structure itself. For most needs desmearing is sufficient whilst for some military applications it is necessary to etchback 75mm for what is referred to as | MULTILAYER BOARDS PROTOTYPING | 3 point contact. Etchback is a stronger chemical attack than desmearing. It is designed to remove not only the smeared resin, but also additional resin | MULTILAYER BOARDS PROTOTYPING | from the wall structure and the remaining protruding glass fibres. There are various methods of desmearing and etchback available to multilayer manufacturers. Permanganate works on | MULTILAYER BOARDS PROTOTYPING | the principle of oxidising the epoxy smear. Advantages are its predictability, its wide operating ...
[ Multilayer Boards Prototyping ]


... call for a great deal of analysis and supervision due to the narrow processing slit. The process of solder mask coating as well as | MULTILAYER BOARDS PROTOTYPING | de- oxidation of bare copper surfaces (activation) must perfectly match the gold plating. To prevent the risk of poor metallic deposition on the gold surface, vias | MULTILAYER BOARDS PROTOTYPING | must be completely free of solder mask coating or be completely closed by means of a special filling process. Curing of the solder mask coating | MULTILAYER BOARDS PROTOTYPING | must also concur with that of the chemical gold plating as it is exposed to hydrogen in the 90° C nickel baths. One has the | MULTILAYER BOARDS PROTOTYPING | choice between an expensive coating system or a subsequent infrared solidification which, in turn, also calls for further investment in facilities. THE POTENTIAL For a | MULTILAYER BOARDS PROTOTYPING | lead free altenative provided the PCB manufacturer ensures optimal conditions for immersion nickel gold coating, the results of wave soldering are equally good to solder | MULTILAYER BOARDS PROTOTYPING | levelling. Good storage ability is also achieved by covering the pad and smd sides with ...
[ Multilayer Boards Prototyping ]


... applied after the screen printing and profiling stages of manufacture. Boards to be treated are chemically etched, cleaned and dried before being passed through | MULTILAYER BOARDS PROTOTYPING | a flood rinse module containing the OSP solution. This solution reacts chemically with the clean copper to form a thin layer of an organic complex | MULTILAYER BOARDS PROTOTYPING | some 0.3 microns thick. Results are monitored on a regular basis by coating test panels and assessing the thickness achieved by UV spectrometric means. Following | MULTILAYER BOARDS PROTOTYPING | treatment, the boards are rinsed to remove residues and dried to obtain a uniform film. Further drying completes the curing of the film, which then | MULTILAYER BOARDS PROTOTYPING | protects the underlying copper from environmental influences and subsequent multipass processing by the customer. Immersion Tin Protection (alternativ) A new modern alternative to hot air | MULTILAYER BOARDS PROTOTYPING | solder level and nickel / gold finishes. A thin (0.1µm - 0.1µm) layer of tin is chemically deposited on the copper pads. Tin is normally | MULTILAYER BOARDS PROTOTYPING | applied after the screen printing and profiling ...
[ Multilayer Boards Prototyping ]