According to the manufacturing process of smt chip factory, all the conductive surfaces in the circuit board are stored on the core surface, and the material of the core surface is generally double-sided clad plate. When the core plane is fully utilized, the number of conductive planes of the printed circuit board is even.
Even-numbered printed circuit boards have cost advantages. Due to the lack of a dielectric layer and a copper-clad layer, the raw material cost of odd-numbered printed circuit boards is slightly lower than that of even-numbered printed circuit boards However, because odd-numbered printed circuit boards need to add non-standard laminated core plane bonding technology on the basis of core plane structure technology, the processing cost of odd-numbered printed circuit boards is obviously higher than that of single-layer printed circuit boards. Even-numbered printed circuit boards. Compared with the common core plane structure, adding copper cladding outside the core layer structure will lead to a decrease in production efficiency and a longer production cycle. The outer core plane needs extra treatment before lamination and bonding, which increases the risk of scratching and mismatch of the outer plane. The increased outer plane treatment will greatly increase the manufacturing cost.
In smt processing, when the inner and outer planes of the printed circuit board are cooled after the multi-layer circuit bonding process, different lamination tension will lead to different degrees of bending of the printed circuit board. And with the increase of circuit board thickness, the risk of bending composite printed circuit boards with two different structures will also increase. Odd circuit boards are easy to bend, and even circuit boards can avoid circuit board bending.
