Introduction to the Processing Technology of Double Layer PCB

Double -layer PCB introduction

Double-sided PCB board is a very important PCB board on the circuit board. On the market, there are double-sided circuit board metal base PCB boards, HI-TG heavy copper foil line boards, flat winding double-sided line boards, high frequency with high frequency PCB, hybrid dielectric base high -frequency double -sided circuit board, etc., it is suitable for extensive high -tech industries such as: telecommunications, power supply, computer, industrial control, digital products, science and education instruments, medical devices, automobiles, aerospace defense, etc.

There is wiring on both sides of the circuit board on the double-layer circuit board, but to use the wires on both sides, there must be an appropriate circuit connection on both sides. The “bridge” between these circuits is called the guide hole. The guide hole is a small hole filled with PCB metal that can be connected to wires on both sides. Because the double panel area is twice that of the single panel, the double panel solves the routing problem in the single panel (can be guided to the other side through the hole), which is more suitable for more complex circuits than a single panel.

2 Layer PCB Manufacturing Process

The overall production process of double-layer board is: opening material – drilling – chemical copper and electroplating copper – graphite transfer – graphite plating and plating protection, tin -etching – intermediate inspection – welding blocking – Indian character – metal surface treatment – finished product molding – electrical test – appearance inspection – packaging shipment.

1. After the original PCB data processing is completed, it is determined that there is no problem and meets the process capacity. Waiting for the production materials. Simply put, it is the material needed for PCB preparation.

2. After drilling on the project data input computer, the calculation machine will automatically locate, in exchange for the drill bit of a different SIZE for drilling. Since the entire PCB has been wrapped, it needs to be scanned with X-Ray. After finding the positioning hole, you need to get a hole.

3. Due to the information of each layer in the PCB, copper plating copper plating on drill holes through drill holes is turned on for layers. Chemical copper reacts with copper plating to achieve PCB function.

4. After the outer compression membrane is placed, the inner and outer layers are connected after passage and the pores are placed, and the inner and outer layers are connected. Next, the outer circuit is made to reach the complete circuit board line. The film is the same as in the previous film. The purpose is to make the outer layer of PCB.

5. The outdoor exposure is the same as before.

6. Outside shows are the same as before.

7. Card etching outer lines in this process formed this process

8. Remove the diaphragm and dry the membrane. This step is to be washed with potions and attached to the dry film that has hardened on the surface of the copper plate. The entire PCB wiring layer has been substantially formed.

9. Spray the appropriate concentration of green paint evenly on the PCB board, or apply the ink to the PCB boardwith a scraper and net version.

10.S/M The part of the green paint must be reserved for light.

11. Washing with water with water is removed without exposure, leaving hardening parts that cannot be washed away. Baking the good green paint and drying, and determining the PCB firmly.

12. Print characters Print on the correct text according to the customer’s requirements, such as the correct text, date of manufacture, part, part, manufacturer, and customer name.

13. In order to prevent PCB exposed copper surfaces from oxidizing and keep it well sold, PCB plants need to be treated with PCBs, such as HASL, OSP, Chemical Silver, Nickel, and Gold.

14. For moulding, the panel panel is cut to the size required by the guest households.

15. Test a 100 % circuit test for the PCB board for the performance required by the customer to ensure that its functionality meets the specifications.

16. The final inspection is based on the test of qualified tests, and the appearance of 100 % inspection according to the customer appearance inspection model.

17. Packaging shipment

Introduction to Ponetic Pole and PM in PCB Double Layer

There are three types of pads, one is a pad pad, and the other is called through the hole, and the other is called buried holes, but buried holes are only used in multi-layer COPY boards. The double panel only requires the first two. These three types of pads can be selected through Layer Selection and Net Selection. Hong Kong chose Multi-Layer. There will be pads on both sides. Connect with copper, so it is connected together. Of course, it is not possible to do the corrosion board yourself, unless you can connect the pores manually yourself. Too many holes are holes. For convenience only, the software separates them.

Minimum holes in PCB double-layer board

The relationship between plate thickness and minimum pores:

Thick board: 3.0mm 2.5mm 2.0mm 1.6mm 1.0mm Minimum pore diameter: 24mil 20mil 16mil 12mil 8mil

The basic deviation of the holes does not directly calculate the formula, but is converted from the basic deviation of the shaft of the same name. Concerning the following two principles during concerts: GM Rules (Relationships): The cooperation nature of the coordination of the same name is the same. That is, when the coordination of the base hole (such as φ30H8/F8) becomes the cooperation of the base shaft system of the same name (φ30F8/H8), its cooperation is unchanged.

How big the needle design needs to be determined according to the pins, and the general capacitor and exclusive plug-in holes are about 1.0mm.

The hole difference between the circuit boards can generally be 0.1mm, and the pin size is also tolerant, so the hole designs are extreme. The size of the hole is the size of the pins+ the normal tolerance+0.1mm, so as to ensure the matching of the pinhole and the pin.

How is PCB double-layer board corrosion?

The etching process of printed circuit boards is usually completed in the corrosion tank. The etching raw material is used for iron chloride. Its solution (FECL3 concentration 30%-40%) is low in price, slow corrosion response speed, easy to control processes, suitable for single and double-sided corrosion of copper plates.

The corrosive solution is usually configured with iron chloride and water. Iron chloride is a yellow solid, and it is also easy to absorb water in the air. Therefore, it should be sealed and stored. When configured with iron chloride solution, it usually uses 40% iron chloride and 60% water. Of course, more iron chloride, or warm water (not hot water to prevent paint from falling off) can make the reaction speed faster. Note that iron chloride has a certain corrosiveness. Try not to touch the skin or clothes. The container that reacts to the container with cheap plastic basins can be placed on the bottom line board.

Starting from the edge to corrode the PCB line board. When the non-painted copper foil is corroded, the line board should be taken out in time to prevent the paint from falling behind and corrosion. At this time, rinse with water, and scrape the paint with bamboo slices and other objects (at this time the paint came out of the liquid, it is easier to remove). If it is not easy to scrape, just flush it with hot water. Then dry it, polish it with sandpaper, and expose the shiny copper foil, and a printing line board is ready.

2 Layer PCB COST

The price of double-layer PCB boards mainly depends on the order volume (number of square meters) and process requirements.

Conventional 4 processes: lead spraying tin, lead-free tin, gold smelting, OSP antioxidant.

Conventional double-layer PCB samples are generally between 200-300. Special craftsmanship, such as gold plated fingers or special materials, will be relatively expensive.

If it is relatively cheap in small quantities, you can talk about it in large quantities.

Batch gold technology is higher than tin spray, and OSP’s antioxidant price is higher. The price of the remaining three processes is almost the same.

If you want to know more about double-layer PCB, you can leave a message. Leadsintec is a professional 2 -layer PCB processing manufacturer. If you have this need, please email us.