The production method of multilayer boards is generally done by the inner layer graphics first, then by printing and etching method to make a single-sided or double-sided substrate, and into the designated layer between, and then by heating, pressing and bonding, as for the subsequent drilling is the same as the double-sided plating through-hole method.
1. First of all, the FR4 circuit board must be manufactured first. After plating the perforated copper in the substrate, the holes are filled with resin and the surface lines are formed by subtractive etching. This step is the same as the general FR4 board except for the filling of the perforations with resin.
2. The photopolymer epoxy resin is applied as the first layer of insulation FV1, and after drying, the photomask is used for the exposure step, and after exposure, solvent is used to develop the lower hole of the peg hole. Hardening of the resin is carried out after the opening of the hole.
3. The epoxy resin surface is roughened by permanganic acid etching, and after etching, a layer of copper is formed on the surface by electroless copper plating for the subsequent copper plating step. After plating, the copper conductor layer is formed and the base layer is formed by subtractive etching.
4. Coated with a second layer of insulation, using the same exposure development steps to form a bolt hole under the hole.
5. If the need for perforation, you can use the drilling of holes to form perforations after the formation of copper electroplating etching to form the wire.
in the outermost layer of the circuit board coated with anti-tin paint, and the use of exposure development method to reveal the contact part.
6. If the number of layers increases, basically just repeat the above steps. If there are additional layers on both sides, the insulation layer must be coated on both sides of the base layer, but the plating process can be carried out on both sides at the same time.
Post time: Nov-09-2022