Multilayer PCB is made of two or more electrically conductive layer (copper layer) composed of the superposition of each PCB. The copper layer is a resin layer (prepreg) are bonded together. Multi-substrate is a printed PCB is the most complex type. As the complexity of the manufacturing process, lower production volume and redo difficulties, making them relatively high prices. As integrated circuit package density increases, leading to a high concentration of interconnecting lines, which makes use of a multi-substrate necessary. Layout of the printed PCB, the emergence of unforeseen design issues such as noise, stray capacitance, crosstalk. Therefore, the printed PCB design must work towards making the minimum length of the signal line and to avoid parallel routes, etc.. Obviously, in a single panel, or is a double panel, since it is possible to achieve a limited number of cross, these requirements can not be satisfied with the answer. A large number of interconnections and cross demand, the PCB to achieve a satisfactory performance, it must be extended to two or more plate layers, resulting in a multilayer PCB. Therefore, the original intention of manufacturing a multilayer PCB is complex and / or noise-sensitive electronic circuits select the appropriate routing paths to provide more freedom. The multilayer PCB has at least three conductive layers, wherein the outer surface layers, while the remaining layer of the insulating plate is synthesized. The electrical connection between the PCB is usually done by the plated through holes on the cross section achieved. Unless otherwise stated, the multi-layer printed PCBs and double sided, as is generally plated through orifice. Two or more substrates is more circuits each made of stacked between them a reliable preset to each other. Since all the layers are laminated together before the drilling has been completed and electroplating, this technique violation from the beginning of the traditional production process. Innermost layers from the traditional two-panel composition, while the outer layer is different, they are made of separate single-panel composition. Before the RCC, the inner substrate will be drilled through-hole plating, pattern transfer, developing and etching. The signal to be drilled outer layer, which is the inside edge of the through hole is formed balanced copper plated ring in such a manner capable of. Each layer is then laminated together to form a multi-substrate, the substrate can be used more for wave soldering (components inter) connected to each other. Rolling may be in the hydraulic pressure chamber or in the ultra (autoclave) of completion. In the hydraulic machine, the prepared materials (for pressure stack) is placed in the cold or preheated under pressure (high glass transition temperature of the material was placed in a temperature of 170-180 ℃). The glass transition temperature of an amorphous polymer (resin) or parts of crystalline amorphous region of the polymer from a hard, very brittle state change into a viscous, rubbery state temperature. The substrate is put into use more specialized electronic equipment (computers, military equipment), in particular in terms of weight and volume overload case. However, this can only increase the cost of the substrate using multiple exchange space .Increases and the weight reduction. In the high-speed circuits, the substrate is more useful, they can be PCB designer to provide more than two wires of the board to the layout and provide a large area of ground and power layer.
Posted on: Fri, 26 Sep 2014 12:22:19 +0000
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