There are Obvious Differences Between Multilayer and Double-sided PCB Circuit Boards in Terms of Process

First of all, multilayer PCBs are made of alternating layers of conductive map and insulating material bonded together, the number of conductive map layers is more than three, and the electrical connection between the layers is realized through metallized holes. The double-sided board is the use of a double-sided board as the inner layer, two single-panel as the outer layer or two double-sided board to do the inner layer, two single-panel as the outer layer, through the positioning system and insulating bonding materials are stacked together, and the conductive graphic interconnections according to the design requirements.

Second, in the production process, multilayer PCBs add several unique process steps, such as imaging and blackening of the inner layer, lamination, concave etching and de-drilling of dirt. These steps differ in terms of certain process parameters, equipment precision and complexity in mostly identical processes. For example, the metallization connection of the inner layers of a multilayer is a decisive factor for the reliability of the multilayer, and the quality of the hole walls is more stringent than that of a bilayer, which makes the drilling of the holes more demanding. In addition, the number of stacked boards per drilling, the rotational speed of the drill and the feed of the drill when drilling are all different for multilayer boards than for double-sided boards.

Finally, there are also differences in inspection. The inspection of finished and semi-finished products of multilayer boards is much stricter and more complicated than that of double-sided boards. Because of the complex structure of the multilayer board, it is necessary to use the glycerin hot-melt process with uniform temperature, instead of the infrared hot-melt process, which may lead to excessive local temperature rise, etc.

From the emergence of electronic products to the present day, it is through every rigorous process of innovation to have the current electronic products, more and more superior in performance, in the shape of more and more small and lightweight. But with the arrival of these sophisticated electronics, PCB circuit boards in the wiring structure is also more and more complex. The previous double-sided board in the space has great limitations, so the PCB board also follow the requirements of all electronic products to innovate, from the original single-sided to double-sided, and then to the emergence of multi-layer carried out in a technical and spatial evolution. So why PCB to multilayer development?

PCB circuit board in the face of high assembly density, small size, light weight, to meet the demand for lightweight and small electronic equipment requirements, with most of the original double-sided PCB circuit board is not able to meet these requirements, the wiring on the precision can not meet, so the need to use to multilayer PCB circuit board, so that you can increase the number of layers of wiring, thereby increasing the design flexibility. Plus multilayer circuit boards can form a certain impedance circuit, can form a high-speed transmission circuit.

Alternating conductive graphic layers and insulating materials pressed together as a multilayer PCB circuit board, the process is generally the first inner layer of the board graphic etching, after the blackening process, according to the predetermined design to join the semi-cured sheet for the addition of layers, and then add the copper foil in the back and back for the compression of the two sides; and the double-sided is not required to double-sided of these steps, it can be taken directly from the material to open the beginning of the process of production.