JS@pcbasic.com

Knowledge Base

The PCB Fabrication Process: A Step-by-Step Guide

PCBasic has many years experience of PCB design and PCB fabrication in Shenzhen, China, and has formed a good reputation in the industry. Professional PCB fabrication and strict PCBA production management specifications have created PCBasic's good reputation in the industry. As an experienced PCB fab, PCBasic has a standardized PCB fabrication process. It can meet the various PCB customization needs of different customers. Let's take a look at the process flow of PCB fabrication.

1. Sending materials

After the customer processed the original data, confirmed that there was no problem, and conformed to the PCB fabrication process, the material was issued. According to the work order issued by the engineer, determine the material that meets the size of the PCB fabrication substrate, the PCB fabrication material, and the number of layers. Simply put, it is to prepare the materials needed for PCB fabrication.

2. Press dry film of inner layer board

Dry film: It is a resist for photosensitivity, imaging, electroplating, and etching. The photoresist is attached to the clean board surface by hot pressing. The water-soluble dry film is mainly due to its composition containing organic acid radicals, which will react with strong bases to become organic acid salts. It can be dissolved in water. It forms a water-soluble dry film developed with sodium carbonate and stripped with dilute sodium hydroxide to complete the imaging action. This step is to "stick" the surface of the processed PCB fabrication board with a water-soluble dry film that will undergo a photochemical reaction, which can be exposed to light to present prototypes of all circuits on the PCB fabrication board.

3. Exposure

After laminating the copper plate, make the negative with the PCB fabrication board. After the computer is automatically positioned and exposed, the dry film on the board is hardened due to the photochemical reaction for subsequent copper etching.

4. Development of the inner layer board

The dry film that has not been exposed to light is removed with a developer solution to leave the exposed dry film pattern.

5. Acid etching

We will etche the exposed copper to obtain the circuit of the PCB fabrication board.

6. Remove dry film

In this step, we will wash away the hardened dry film attached to the surface of the copper plate with chemical water, and the entire PCB fabrication circuit layer has been roughly formed by now.

7. AOI

With automatic optical alignment and maintenance machines, alignment detection is performed against the correct PCB fabrication data to detect a short circuit or other conditions. If this is the case, then check and repair the PCB fabrication situation.

8. Blackening

This step is to treat the copper on the PCB fabrication board surface that has been checked and repaired with a chemical solution. Make the copper surface fluffy and increase the surface area to facilitate the adhesion of the two-sided layers during PCB fabrication.

9. Pressing

Use the hot pressing machine to press the steel plate on the PCB fabrication board. After a certain period, after reaching the required thickness and confirming complete bonding, the bonding of the two PCB layers is considered complete.

10. Drilling

After inputting the engineering data into the computer according to the PCB fabrication, the computer will automatically locate it. Exchange for drills of different sizes for drilling. Since the entire PCB has been packaged, we need to scan it with X-RAY. After finding the locating hole, drill the bit holes necessary for the drilling program.

11. PTH

Since there is no conduction between the layers during the PCB fabrication, it is necessary to plate copper on the drilled holes to conduct interlayer conduction. But the Resin between the layers is not conducive to copper plating, and a thin layer of chemical copper must be produced on the surface. Then we will carry out the copper plating reaction to make it meet the functional requirements of PCB fabrication.

12. Outer laminated film

After pretreatment and through-hole plating, we will connect the inner layer and the outer layer. Next is the outer circuit of the PCB fabrication board to make the circuit board complete. The lamination is the same as the previous lamination step. And the purpose is to make the outer layer of the PCB.

13. Outer layer exposure

Same as the previous exposure steps.

14. Outer layer development

Same as the previous development step.

15. Line etching

The outer circuit of the PCB fabrication board is formed in this process.

16. Remove dry film

In this step, we will wash away the attached copper plate and the hardened dry film on the surface with the chemical water, and the circuit layer of the entire PCB fabrication board has been roughly formed.

17. Spraying

Spray the appropriate concentration of green paint evenly on the PCB fabrication board, or evenly coat the ink on the PCB board by means of a scraper and a screen.

18. S/M

Using light will harden the part that needs to be left in the green paint. we will wash away the unexposed parts during the development process.

19. Visualization

Wash off the unexposed hardened part with water, leaving the hardened part that cannot be washed away. Bake and dry the top green paint and firmly adhere to the PCB fabrication board.

20. Printed text

According to the customer's requirements, we will print the correct text on the appropriate screen, such as the part number, manufacturing date, part location, manufacturer and customer name, and other information.

21. Spray tin

In order to prevent oxidation of the bare copper surface of the PCB fabrication board and maintain good solderability, PCB fab needs to perform surface treatment on the fabrication board, such as HASL, OSP, chemical immersion silver, nickel immersion gold...

22. Molding

Use a CNC milling cutter to cut the PCB fabrication board of the large Panel to the size required by the customer.

23. Test

According to the performance required by the customer, we will perform 100% circuit testing on the PCB fabrication board to ensure that its functionality meets the specifications.

24. Final inspection

For PCB fabrication boards that have passed the test, we will do 100% appearance inspection according to the customer's appearance inspection specifications.

25. Packaging

UET Co., Ltd. gives you the best quality SMT chip processing, PCB fabrication, embedded system research and development, electronic processing, embedded motherboard, PCBA packaging materials, PCBA processing services.


Conclusion

The above is the relevant knowledge about the PCB fabrication process. As an established PCB fab in Shenzhen, UET provides customers with high-quality PCB fabrication services. At the same time, we have rich experience in PCBA processing and provide cheap PCB fabrication services. In addition to PCB design and PCB fabrication, UET also undertakes prototype PCB fabrication projects.

1597
Quote
E-mail
X