What is PCB plug hole? Why plug holes?How to achieve it

The connection of the line -to -hole line connecting the line, the development of the electronics industry, also promotes the development of PCB, and also puts forward higher requirements for the production process and surface paste of the printing board. VIA Hole plunged holes came into being, and the following requirements should be met at the same time:

(1) There are copper in the pores, and the welding can be stuffed or plug;

(2) There must be tin lead in the pores, and there must be a certain thickness requirements (4 microns). There must be no welding ink ink into the hole, causing tin beads in the hole;

(3) The pitch must have a welding ink plug hole, which is opaque, and there must be no requirements for tin ring, tin beads, and flat.

With the development of electronic products in the direction of "light, thin, short, small", PCB also develops towards high density and difficulty. Therefore Five functions:

(1) To prevent PCB from welding, tin tin can be short -circuited from the tin through the tin through the tin; especially when we put the perforated on the BGA pad, we must first do the holes and then gold plated to facilitate the welding of BGA.

(2) Avoid the residual welding in the pores;

(3) The surface installation of the electronics plant and the component assembly are completed after the PCB must be absorbed on the test machine to form negative pressure before completing:

(4) To prevent the inflow of the surface of the surface of the surface into the hole and cause the virtual welding, affect the paste;

(5) Prevent tin beads popping up when welding over the peak, causing short circuit.

The plug holes are divided into resin plug holes and plating plug holes.

Resin plug hole: The use of solid -free ink plug holes with a solvent is not easy to fill the problem in the general ink, which can reduce the heating of the ink and produce "cracks". Generally, it is used when the aperture with a large vertical and horizontal.

The benefits of resin plug:

1. Pole plug holes on the multi -layer board BGA, using resin plug holes can reduce the pores and pores to solve the problem of wires and wiring;

2. The buried holes of the inner HDI can balance the contradiction between the thickness control of the medium layer and the inner HDI buried hole filler design;

3. Pass with a large thickness of the board can improve the reliability of the product;

4. PCB uses resin plug holes. This process is often because of BGA parts, because traditional BGA may do VIA on the back between PAD and PAD, but if the BGA is too dense, it can be directly from the PAD. Drilling the VIA to other layers to go, and then fill the copper plating with resin to PAD, which is commonly known as VIP process (VIA in Pad). It is easy to cause tin leakage and air welding on the back and front.

The process of PCB resin plug holes includes drilling, plating, plug holes, baking, grinding, and coating on the hole after drilling, and then baked the resin. Finally, the ground is smoothed. Copper contains, so you need to put a layer of copper to turn it into PAD. These processes are done before the original PCB drilling process, that is, the holes of the fortress holes are processed, and then drill other holes for other holes. Originally normal process.

If there is no stuffy hole in the holes, when there is bubbles in the hole, because the bubbles are easy to absorb moisture, the board may explode when the board passes through the tin furnace. Squeezing out, causing a prominent situation on one side. At this time, the bad products can be detected, and the board with bubbles may not be burst, because the main reason for the explosive board is moisture, so if the board or board of the factory just leaves the factory is on the factory, the board is on the factory on the factory, the board is on the factory on the factory. When the upper part is baked, it will not cause explosive boards.

Electroplating hole: It is currently using the characteristics of additives to control the growth rate of copper in each part to perform perforation. It is mainly used for continuous multi -layer flip production (blind hole process) or high -current design.

Advantages of electroplating hole filling:

(1) It is conducive to designing stacked holes and plate holes;

(2) Improve electrical performance and help high -frequency design;

(3) Help heat dissipation;

(4) One step is to complete the connection of plug holes and electrical connections;

(5) Fill in copper plating in the blind hole, more reliability, and conductive performance better than conductive glue.

So, how is the PCB line board drive the holes of the holes?

1. After the hot air is flat, the plug hole process

This process process is: plate surface welding → hal → plug holes → curing. The non -plug -in -hole process is used for production. After the hot air is flattened, the aluminum sheet version or the ink net is used to complete the pores of all fortress. Pluged ink can be used for photosensitive ink or thermos ink. This process can ensure that the heat wind does not drop the oil after the thermal wind is flat, but it is easy to cause the plug in ink pollution plate surface and unevenness, and it is easy to cause virtual welding during installation.

Second, the hot air before the flat plugged hole process

(1) Use aluminum plug holes, solidification, and grinding board for graph transfer

This process uses a digital drilling machine to drill out the aluminum sheets of the Putca holes to make the network version and perform the holes. The plug -in ink can also be used with armal solid ink. The process process is: front treatment → plug hole → grinding board → graphic transfer → etching → plate surface welding

This method can ensure that the pores are flat, the hot air is flat, and there will be no quality problems such as explosive oil and oil loss of oil.

(2) After using aluminum pieces plug holes, directly welded welding

This process uses a digital drilling machine, drilled out the aluminum sheets of the Plug holes, made into a network version, installed on the wire printer for plug holes, and the parking holes were parked at no more than 30 minutes. The process is: Prelimal treatment -plug hole -silk print -pre -baking -exposure -showing -curing.

This process can ensure that the puppet holes are well covered, the plug holes are flat, and the hot air can ensure that the puppet hole is not on tin, and the tin beads are not hidden in the hole, but it is easy to cause the ink pad in the ink in the hole in the hole, resulting in welding can be welded. Poor sex.

(3) Aluminum plug holes, showing, pre -curing, and plate surface welding block after grinding

Use CNC drilling machine to drill aluminum sheets that require plugs, make the network version, and install the plug holes on the shift wire printer; the plug holes must be full, the both sides are prominent, and then solidified, and the grinding plate is treated with plate surface treatment. Its process process is: Preliminary treatment -plug -hole -pre -baking -showing -pre -curing -pre -firing and welding.

This process is solidified by plug holes, which can ensure that the holes will not be dropped and oil -explosive after the HAL; but after HAL, it is difficult to completely solve the holes and tin beads and the tin on the pilot.

(4) Plate surface welding and plug holes are completed at the same time

This method uses a 36T (43T) silk mesh, which is installed on the wire printer, using a pad or a nail bed. While completing the surface of the board, all the pores are stuffed; the process process is: front processing-silk print- -Pre-baking-Exposure-Selection-CIT.

This process has a short process and the use of equipment is high. It can ensure that the heat wind can not drop the oil after the heat is flattened, and the puppet hole cannot be on the tin. , The air expansion, breaking through the welding film, causing empty holes and unevenness.