pcb production process flow and diagrams

About pcb production process and diagrams are as follows:

For the designers, our main consideration is the minimum line width of the wiring, spacing control and wiring uniformity. Because the pitch is too small will cause clamping film, the film can not fade out causing short circuit. Line width is too small, the film adhesion is not enough, resulting in open circuit. So the circuit design of the safe spacing (including line and line, line and pad, pad and pad, line and copper surface, etc.), must be considered when the production of the safe spacing.

1, pre-treatment: grinding plate. The main role of the grinding plate: the basic pre-treatment is mainly to solve the problem of surface cleanliness and surface roughness. Remove oxidation, increase the roughness of the copper surface, easy to film attached to the copper surface.

2, the film: the treated substrate by hot pressing or coating the way to apply a dry film or wet film, to facilitate the subsequent exposure production.

3, exposure: the negative and pressed dry film substrate alignment, in the exposure machine using ultraviolet light, the negative graphics transferred to the light-sensitive dry film.

4, development: the use of developing solution (sodium carbonate) of the weak alkaline will be unexposed dry film/wet film dissolved rinse off, the exposed part of the retention.

5, etching: unexposed dry film / wet film by the developer to remove the copper surface will be exposed, with acidic copper chloride will be exposed to this part of the copper surface of the dissolution of the corrosion, to get the desired line.

6, the film: will protect the copper limb width and surface of the exposed dry film with sodium hydroxide solution stripped off, revealing the line graphics.

7, brown: purpose: is to make the inner layer of copper surface to form microscopic rough and organic metal layer, enhance the adhesion between the layers.

8, lamination: lamination is with the help of pp sheet adhesive properties of the various layers of the line bonded into a whole process. This bonding is through the interface between the macromolecules of mutual diffusion, penetration, and then produce intertwined and realize the discrete multilayer board and pp sheet together with the press into the required number of layers and thickness of the multilayer board. The actual operation will be copper foil, bonding sheet (semi-cured sheet), the inner layer of the board, stainless steel, isolation board, kraft paper, the outer layer of steel and other materials in accordance with the process requirements of the laminated.

9, drilling: the circuit board layer to produce through-hole, to connect the purpose of the interlayer.

12, the outer layer of graphic plating, SES: the holes and line copper layer plating trick up to a certain thickness (20-25um) to meet the final PCB board finished copper thickness requirements. And the board will not be used to etch off the copper, revealing the useful line graphics.

13, soldermask: soldermask, also known as anti-solder, green oil, is one of the most critical processes in the production of printed circuit boards, mainly through screen printing or coating soldermask ink, coated with a layer of soldermask on the surface of the board, through the exposure of the development, revealing to be welded to the plate and the hole, and elsewhere covered with a layer of soldermask, to prevent the welding of short circuits

14, silkscreen characters: will be the required text, trademarks or parts Symbols, printed on the board by means of stencil printing, and then exposed on the board by means of ultraviolet irradiation.

15, surface treatment: bare copper itself is very good solderability, but long-term exposure to air is susceptible to moisture oxidation, tends to exist in the form of oxides, it is unlikely to remain for a long time for the original copper, so the need for surface treatment of the copper surface. The most basic purpose of surface treatment is to ensure good solderability or electrical properties.

16, molding: PCB to CNC molding machine to cut into the required form factor.

17, electrical test: simulate the state of the board, power on the electrical properties to check whether there is an open or short circuit.

18, final inspection, sampling, packaging: the board's appearance, size, aperture, board thickness, marking and other checks to meet customer requirements. The qualified products will be packaged into bundles for easy storage and transportation.