In terms of fields, there are many Shenzhen circuit board factories that only make one or two application fields, while some can make circuit boards in multiple application fields. Circuit board manufacturers (Shenzhen Senyan) can produce high-precision multilayer circuit boards in high-tech applications such as industrial control, communications, medical treatment, military industry, security, and aerospace. From the structure of the circuit board, it can also be made of single-sided and double-sided circuit boards and PCB multi-layer circuit boards. Today, Shenzhen Circuit Board Factory focuses on introducing the application fields and structures of multilayer circuit boards.
1. Cross-sectional geometric structure of multilayer circuit board
According to the number of layers of the circuit, the multilayer printed circuit board will have a structure of single-sided, double-sided, 4-layer, 6-layer, 8-layer, etc. As for the high-density HDI circuit board that is often mentioned recently, because the usual manufacturing method is to build a core hard board in the center, and use this as a basis to make growth layers on the upper and lower sides, so there are two common names, One is to use the number of hard board layers in the center as the first number, and the number of wire layers on both sides as the other number, so there are descriptions of so-called 4+2, 2+2, 6+4 and so on. But another name may be easier for people to understand the actual situation, because most multilayer circuit board designs use symmetrical designs, so the names of 1+4+1, 3+6+3, etc. are used. Some people say that the structure of 2+4 may be an asymmetric structure, which must be confirmed.
2. The way of connection between multi-layer circuit boards
The circuit board builds the metal layer on the independent circuit layer, so the vertical connection between the layers is indispensable. In order to achieve the purpose of interlayer connection, it is necessary to use the drilling method to form a path and form a reliable conductor on the hole wall to complete the connection of power or signal. Since through-hole plating was proposed, almost all multilayer circuit boards have been produced by this method.
The increased-density multilayer circuit board adopts the build-up manufacturing mode. Its method is to form small holes in the dielectric material by means of laser or photosensitive, and then conduct it by electroplating. Some manufacturers also fill the connection holes with conductive glue to achieve conduction. ALIVH and B2it developed in Japan fall into this category.
3. Application fields of multilayer circuit boards
PCB multilayer printed circuit boards generally have plated through holes as the core, and the number of layers, board thickness, and hole configuration vary with the circuit density. Most of the classification of its specifications is based on this. Rigid-flex boards are mostly used in military, aerospace and instrumentation. Under the premise that electronic products tend to be multi-functional and complex, the contact distance of integrated circuit components will be reduced accordingly, and the speed of signal transmission will be relatively increased. Sexuality is shortened, which requires high-density circuit configuration and microvia technology to achieve the goal. Wiring and jumpering are basically difficult for single-sided and double-sided circuit boards, so the circuit board will become multi-layered; and due to the continuous increase of signal lines, more power layers and ground layers will become design constraints. Necessary means, these have made multilayer printed circuit boards more common.
