Double-Sided PCB Board Manufacturing Process

In recent years, the typical processes for manufacturing double-sided metalized PCB are the SMOBC method and the pattern plating method. In some specific occasions, the process wire method is also used.

1. Graphic Electroplating Process

Foil-clad board → blanking → punching benchmark holes → CNC drilling → inspection → deburring → electroless thin copper plating → thin copper electroplating → inspection → brushing → filming (or screen printing) → exposure and development (or curing) → inspection board repairment→graphic plating (Cu＋Sn/Pb)→film removal→etching→inspection and board repairment→plug nickel plating and gold plating→hot melt cleaning→electrical continuity inspection–>cleaning treatment→screen printing solder mask pattern→curing→screen printing mark symbol → curing → shape processing → cleaning and drying → inspection → packaging → finished product.

In the process, the two processes of “electroless thin copper plating → thin copper electroplating” can be replaced by a single process of “electroless thick copper plating”, and both have their advantages and disadvantages. Pattern electroplating-etching method to make double-layer metalized plates is a typical process in the 1960s and 1970s. In the mid-1980s, the bare copper-clad solder mask process (SMOBC) gradually developed, and has become the mainstream process, especially in precision double-sided panel manufacturing.

2. SMOBC Process

The main advantage of SMOBC board is that it solves the short-circuit phenomenon of solder bridging between thin lines. At the same time, due to the constant ratio of lead to tin, it has better solderability and storage properties than hot melt board. There are many methods for manufacturing SMOBC boards, including the SMOBC process of standard pattern electroplating subtraction and lead-tin stripping; the subtractive pattern electroplating SMOBC process of using tin plating or immersion tin instead of electroplating of lead-tin; the plugging or masking hole SMOBC process; additive method SMOBC technology and so on.