What is the multilayer circuit board
The production of the positive film is in the development and then plating the second copper and tin lead (the region of tin in the subsequent copper step will be retained as a corrosion inhibitor), to the membrane after the alkaline Ammonia, copper chloride mixed solution will be exposed to the corrosion of copper foil removed to form a line. And finally to tin lead stripping liquid will work
In the line image transfer printing as the inner line, but in the circuit etching is divided into positive and negative two production methods. Negative film production methods as the inner line of production, in the development of copper directly after the film to complete the film
The circuit board immersed in the chemical copper solution, the palladium by the catalytic role of the solution in the copper ion reduction deposition attached to the hole wall, the formation of through-hole circuit. And then copper bath plating method will be through the hole in the copper layer thick enough to resist the subsequent processing and the use of environmental impact of the thickness.
In the formation of layers through the hole after the formation of metal copper layer on its need to complete the inter-layer circuit conduction. First with a heavy brush and high pressure flushing the way to clean up the holes on the hole and the hole in the dust, and then to potassium permanganate solution to remove the hole on the copper surface of the glue residue. In the clean hole on the wall soaked with tin palladium paste layer, and then reduced to metal palladium.