Regarding the circuit board manufacturing industry, there has always been a hustle and bustle. In order to grab the attractive cake of PCB multilayer circuit boards, people have been rushing in and funds have been rushing in. Is it true that the company will accept all orders? The answer is of course no. Each Beijing circuit board factory needs to choose cakes according to its own situation. The cakes are too big, greasy and wasteful, so it is necessary to choose the right cake size. Especially Shenzhen PCB circuit board proofing manufacturers, it is necessary to set the cake size to avoid waste.

　　Now we introduce the Beijing Circuit Board Factory. Before introducing the multilayer printed circuit, we will mention a process that can increase the density: jumper or crossover. Perhaps people who have just entered the circuit board proofing industry don't know much about it. Jumper or jumper means that a certain conductor on the wiring layer of the circuit board can "jump" over one or more conductors without short-circuiting the skipped wire. A variety of methods have been developed for jumper or crossover, and all have been successful to varying degrees.

　　Beijing Circuit Board Factory tells you that a simple process but may have reliability problems is to print jumpers. The specific method is: first coat a layer of dielectric on the existing conductors to be skipped, and then apply conductive paste to Connect the conductors that need to be connected at both ends, and no electrical contact occurs with the skipped conductor. This method usually utilizes screen printing and needle coating techniques. If the coated dielectric layer has defects, problems will arise. These defects may be caused by voids in the screen printing process, or may be caused by solvent evaporation during the curing of the dielectric layer (if the dielectric material contains a large amount of solvent).

　　PCB multilayer circuit board production

　　PCB multilayer circuit board production

　　The second reliability problem may occur at the interface between the jumper and the connected conductor. Unless there is a layer of non-oxidizable material (such as gold) on the surface of the metal conductor, the surface of the metal conductor will be oxidized and the printed conductive paste The electrical conductivity between them decreases with time. Jumper technology can be applied to various Shenzhen circuit board factory circuit boards, but it is more suitable for flexible circuit boards, especially polymer thick film (PTF) circuit boards, as detailed later.

　　The last category is multi-layer circuit boards. Although some Beijing circuit board factories have already known it, you have to know that this structure includes at least three separate conductor layers or planes. Of course, since these layers are made in pairs, the number of wiring layers in a multilayer circuit board is usually an even number. The initial production process includes: stacking multiple double-sided circuit boards together, drilling the holes as a whole, and then realizing the interconnection in the vertical direction. The connection in the vertical direction used pins, rivets and screws in the early days, and the plated through-hole technology has achieved a breakthrough because all connections in the vertical direction can be completed at one time. After so many years, a variety of new vertical connection technologies have been developed, with success to varying degrees. Some technologies use a layered strategy, where only one layer of circuit is made at a time. There are other methods, such as coating a conductive adhesive film on the two sides of the pair as an interpo-ser.

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