Multilayer PCB Manufacturing
2022-11-10 16:05:55 Multilayer PCB Manufacturing 406 Viewed
Multilayer PCB Manufacturing difficulties?
Multilayer PCB manufacturing products in communications, medical, industrial control, security, automotive, power, aviation, military, computer and other fields occupy an influential position. With the increase of product function, the line is more and more dense, the production is more and more difficult. At present, the domestic multilayer PCB manufacturing, only a few enterprises have the strength of batch. What are the main processing difficulties encountered in the production of multilayer PCB manufacturing?
1. The inner line of multilayer PCB manufacturing is difficult to produce
The circuit in multilayer PCB manufacturing has special requirements of high speed, thick copper, elevated frequency, high Tg value, and more and more requirements for inner wiring and graphic size control.
2. Multilayer PCB manufacturing between the inner difficult alignment
Multilayer PCB manufacturing further and additional layers, the inner layer of the matching requirements are also higher and more elevated. The film produced by multilayer PCB manufacturing will grow and shrink under the influence of ambient temperature and humidity in the workshop, while the core board will grow and shrink in the same way after production, which makes it more difficult to control the alignment accuracy between the inner layers.
3. The pressing process of multilayer PCB manufacturing is difficult
The superposition of multiple core boards and PP is prone to problems such as layering, skateboard and drum residue when pressing. With numerous layers, the control of growth and shrinkage and size coefficient compensation cannot be consistent. multilayer PCB manufacturing has thin insulation between layers, which easily leads to failure of inter-layer reliability test.
4. Drilling production of multilayer PCB manufacturing is difficult
Multilayer PCB adopts steep Tg or other special plates, and the roughness of drilling is different with different materials, which increases the difficulty of removing the glue residue in the hole.
Multilayer PCB Manufacturing advantages
PCB are ubiquitous these days, at the heart of most electronics. As devices become more complex, so do PCB. Advantages of multilayer PCB manufacturing:
Lightweight players: Single-layer and double-layer PCB require a large number of connectors, adding weight and thus limiting mobility. Multilayer PCB manufacturing has strong reliability and superior quality.
Durability: Multilayer PCB manufacturing is considerably durable because they can withstand the heat and pressure applied to them.
Flexibility: For components using flexible construction technology, flexible multilayer PCB manufacturing facilitates applications with a certain degree of bend.
Single connection point: With only one connection point, multilayer PCB manufacturing is beneficial for devices with size and weight limitations.
Multilayer pcb manufacturing process steps
1. Cut Lamination
Cut Lamination is the process of cutting the original copper-covered sheet into a multilayer pcb which can be produced on the production line.
2. Inner dry film
The inner dry film is the process of transferring the inner circuit pattern to the PCB board. In multilayer pcb manufacturing, graphics transfer will be involved, because the production of conductive graphics is the foundation of multilayer pcb manufacturing, so the graphics transfer process for multilayer pcb manufacturing has a considerably crucial significance.
The purpose of brownization of multilayer pcb manufacturing is to make the inner copper surface form a microscopic rough and organic metal layer to enhance the adhesion between layers.
The lamination of multilayer pcb manufacturing is the process of bonding the lines of each layer into a whole by virtue of the adhesivity of pp sheet. This bonding is through the mutual diffusion and penetration of macromolecules on the interface, and then the interwoven multilayer pcb is produced.
The multilayer pcb manufacturing layer through holes, to achieve the purpose of connecting the layers.
6. Sinking copper
Also called chemical copper, the PCB after drilling in heavy copper oxidation reduction reaction occurs in the cylinder, forming the copper layer, and the hole metallization, make originally the insulation on the substrate surface deposition of copper, achieving multilayer PCB manufacturing electrical connected between the layers.
7. Outer dry film
Same process as the inner dry film.
9. Outer graphic plating
It means that the hole and line copper layer are plated to a certain thickness (20-25um) to meet the requirements of the copper thickness of the final PCB board, and the unused copper on the surface of multilayer pcb manufacturing is etched away to expose the useful line graphics.
10. Solder resistance
It is one of the most critical processes in multilayer pcb manufacturing. It is mainly through screen printing or coating with solder resistance ink, coating a layer of solder resistance on the board surface, exposing the plates and holes to be welded through exposure development, and covering additional places with solder resistance layer to prevent short circuit during welding.
11. Silkscreen characters
The required text, trademark or part symbol is printed on the multilayer pcb manufacturing surface by means of screen printing, and then exposed on the board surface by means of ultraviolet irradiation.
12. Surface treatment
The most basic purpose of multilayer pcb manufacturing surface treatment is to ensure acceptable stability or electrical properties.
PCB was cut into the desired shape size by CNC machine.
14. Electrical measurement
Simulate the status of the board, electrify for electrical performance check, whether there is open, short circuit.
15. Final inspection, sampling and packaging
Check the appearance, size, aperture, plate thickness and marking of multilayer pcb manufacturing to meet customer requirements and pack qualified products into bundles for easy storage and delivery.
Multilayer pcb manufacturing surface treatment
The circuit board is mainly composed of welding pad, through hole, mounting hole, wire, components, connectors, filling, electrical boundary and so on. Common structures include Single Layer PCB, Double Layer PCB, and multilayer pcb.
Multilayer pcb manufacturing is the product of electronic information technology to high speed, Multi-function, large capacity, limited volume, thin and lightweight. Surface treatments for multilayer pcb manufacturing are HASL, OSP, ENIG, Ag, Imm Gold Finger, Imm Tin and so on.
Huihe Circuit multilayer pcb manufacturing products are used in mobile phones, tablets, laptops, industrial power supplies, HDTV and other high-tech products, products throughout China, Hong Kong, Japan, the United States, Europe and other parts of the world.