PCB complete processing

Most engineers can wait for the board to return after sending the PCB file or gerber file to the manufacturer. But often the hardware research and development job has not had the opportunity to go to the PCB production plant for many years to see the entire production process.

Take you there today. Take a look at the complete process.

First step, cutting

The raw materials of the PCB board factory are generally 1020mm×1020mm and 1020mm×1220mm. If the size of the single board or the jigsaw is not suitable, in the PCB production process, a lot of waste materials will be produced, and the PCB board factory will put it. The price of some waste edges is added to your board, so your PCB board price is more expensive; if the board size is well designed, the size of the board or panel is n equal parts of the raw materials, then the utilization of raw materials The highest, PCB board factory is also good to open, with the same raw material size, make the most board, the price of the board is the cheapest.

Cutting equipment: (cut the big board into small boards)

The earliest copper clad laminate was a dielectric layer with copper on both sides.

The figure above is a cross-sectional view of a copper clad laminate.

Second step, typesetting

The third step: film

Import and modify the graphic files provided by the customer through the software, and finally output the graphics on the film. It is to turn the gerber file you give to the manufacturer into film.

Film is film or silver salt photographic film, also known as film. Made of PC/PP/PET/PVC material. Now generally refers to film, but also refers to the film in the printing plate. The film is black

The fourth step, exposure

A layer of photosensitive liquid is applied to the surface of the copper clad plate. After 80 degrees of temperature test, it is baked and dried on the PCB board, and then exposed to the ultraviolet exposure machine to remove the film.

The picture below shows the exposure machine:

The fifth step, etching

A single etching process can be broken down into the following steps

PCB etching machine

The board flows under the roller

Why is the etching method inside and outside the PCB different?

Inner layer: development → etching → stripping

Outer layer: development → two copper tin plating → stripping → etching → stripping tin

Why do you do this? Is the outer layer etched more than the process?

The inner layer generally has a large line width and a large line spacing, so the Ring ring is sufficient; the outer layer is generally dense and the space is not enough, so at this time, it is necessary to find a way to achieve the purpose of making the line in an insufficient space. The ability to erode can reach 1~2mil ring, but the acid etching needs about 5mil, so it is necessary to use tin to protect the required line first. Try not to do it where you can avoid eclipse, because the cost of erosion is higher than that of acid etching. The etch factor is a factory's ability to be manufactured and cannot be improved through processes. The etching ability of acid etching is different.

Step 6, drilling

The machine drills holes in the PCB according to the size and coordinates of the vias in the file.

If a non-metallic hole is made, the circuit board factory must use a dry film or do two diamonds or a plug rubber. No matter how it is done, it will increase the cost of the board. So if you don't ask for it, the board factory will usually make metal holes for you.

The seventh step, sinking copper

Copper is deposited on a non-conductive substrate (hole wall) and copper surface with a layer of chemical thin copper.

The eighth step of green oil, characters

PCB low temperature UV machine, use: UV (UV) coating coating curing

Brush characters:

Character screen

Final step, comprehensive inspection

When the sample is processed, the factory generally does not do the fixture for testing and manual testing; if the batch is small, the factory needs to make the test fixture to test the impedance and connectivity of all the traces.