2019年5月22日星期三

Copper foil layer is bonded together

Copper foil layer is bonded together by PP(prepreg), Multilayer board is one of the most complex types in printed circuit board.
Multilayer PCB is made up of three or more conductive layers(copper foil layer), these layers are pressed together and form multilayer circuit board. In the early stage, copper substrate mainly used paper phenolic aldehyde, but because paper phenolic aldehyde with the factors of low electric insulation, bad solder thermal stability, twist issue etc, paper epoxide resin and glass fiber epoxy resin was developed soon after. Currently, paper epoxide resin is widely used in consuming electronic.
With the appearance of electronic transistor, single sided board was developed in the early of 1950, which is mainly manufactured in USA. The main focus for circuit board manufacturer is how to control production cost and save more cost for customers. In the layout of printed circuit boards, sometimes it will have some unforeseen design problems, such as noise, stray capacitance, crosstalk and so on, therefore, when design printed circuit board, it must be committed to make the length of signal wire as short as possible and avoid parallel circuits, etc. In the demand of mass interconnection and interdigitation, if printed circuit board wants to achieve a satisfactory performance, it must be extend to more than two layers, thus the multilayer PCB appeared.
For Single sided PCB, the components are on one side, conducting wires are on the other side, single sided PCB is the most simple and basic circuit board. During 1953 to 1955, Japan use imported copper make out paper phenolic aldehyde copper substrate, and apply mainly on radio products.
Due to the packaging Stainless steel ground rod density increase in integrated circuit, which bring about interconnect highly concentrated, thus using multilayer circuit board become necessary. The electrical connection between each layer is usually realized by plated through hole. In 1956, single sided circuit board technology was made big progress with the appearance of professional PCB manufacturers from Japan.
Basically, there is no challenge for printed circuit board manufacturer to produce single sided PCB and the technology is quite mature nowadays. Single sided circuit board was manufactured by copper etching directly at that time.
PCB prototype manufacturer in China with more than 10 years PCB manufacturing experience, offers Single sided PCB, Double sided PCB and Multilayer PCB. Unless special instructions, both multilayer PCB and double sided PCB are plated through hole printed circuit boards. Because of the complexity in PCB manufacturing process, low yield rate and difficulty of rework, making the price is relatively high.

Multilayer PCB at least has three conductive layers, two layers on surface side, and the rest of the layers are synthesized inside the insulation part. Obviously, it is hard to get satisfied solution from single sided PCB or even double sided PCB, due to the cross circuit number is limited

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