At present, the core board is composed of complex circuit design, and the complex circuit design into thin core board can not be separated from multilayer PCB (MLB) manufacturing technology.
Multilayer PCB (MLB) manufacturing technology development speed, especially in the late 80, with high density I/O (input/output) lead number of VLSI, ULSI integrated circuits, SMD devices and the development of SMT, the use of multilayer PCB manufacturing technology to achieve a high level of technology. will also be with the "light, thin, short, small" components are a large number of widely used, SMD high-speed development and SMT popularization, interconnect technology more complicated, Multilayer PCB prompting multi-layer plate manufacturing technology to fine line width and narrow spacing, thin-type high-rise, micro-aperture direction of development. Multilayer PCB Multilayer PCB technology transformation, that is, multilayer PCB manufacturing technology has been widely used in civilian electrical appliances.
The development of MLB is usually divided into two categories according to the range of application: One is the basic components of electronic machine, the other is used to install electronic components and interconnect substrates, and the other is used for all kinds of chips and integrated circuit chip board. The MLB conductive graph used for carrying plate is more fine, the performance of the substrate is stricter, Multilayer PCB and the manufacturing technology is more complicated.
The process characteristics of multilayer PCB are as follows:
2.1 High density of core board
The high density of multilayer board means that the technology of fine wire technology, micro-aperture technology and narrow ring width or ring-free width are used to improve the assembling density of PCB. The basic situation of high density interconnect technology of multilayer Board see the table below (table 2-1):
2.2 High fine 2.2 high fine wire technology
High density interconnected structure of laminated multilayer board, the use of circuit graphics need a high-precision wire width and spacing between 0.05-0.15 mm. Multilayer PCB The corresponding manufacturing process and equipment should have a high precision, high-density fine lines of process technology and processing capacity.
2.3 Micro-aperture technology
With the reduction of the aperture of multilayer plate, higher technical requirements are put forward for drilling process equipment, and all chemical plating and direct electroplating technology should be adopted to solve the problems of adhesion and ductility of small-hole electroplating.
2.4 Core Plate reduction hole width size
The size of the space around the ring is reduced, which can increase the wiring space, Multilayer PCB thus further improving the circuit graphics density of multilayer boards.
2.5 Thin multi-layer technique
Thin-layered technology fully adapts to the components of "light, thin, short, small" and high-density technical requirements. The current development trend of multilayer PCB manufacturing technology is divided into: high-rise thin plate and general thin plate. The thickness of the tall thin Multilayer board will be 0.6-5.0MM, layer from 12-50 layer or higher; thin multilayer plate thickness will be 0.3-1.2MM, layer from 4-10 layers or higher.
2.6 Multi-layer board structure diversification
With the high stability and high reliability of the precision devices, Multilayer PCB the density requirement and the interconnection quantity and complication of multilayer board manufacturing are more and more inevitable.