Design of Conductive Pore Hole for Rigid PCB Design
In order to meet customer requirements, the vias must be plug holes, after a lot of practice, change the traditional aluminum plug hole process, with the white network to complete the board resistance welding and plug hole. Production is stable and reliable.
The opening of the Via hole leads to the development of the electronics industry, but also promotes the development of rigid PCBs, and also puts forward higher requirements for PCB fabrication technology and surface mount technology. The Via hole process is in place and should meet the following requirements:
(A) within the hole can be copper, solder can be plug can not plug;
(B) must have tin lead lead, there is a certain thickness requirements (4 microns), shall not have solder resist ink into the hole, resulting in possession of tin hole in the hole;
(C) vias must have solder mask ink plug hole, not light, no tin ring, tin beads and leveling requirements.
With the electronic products to the "light, thin, short, small" direction, rigid PCB to high density, difficult development, so a large number of SMT, BGA rigid PCB, and customers in the placement of components required plug hole, There are five main roles:
(A) to prevent the rigid PCB over-wave soldering tin from the through-hole through the element surface caused by a short circuit; especially when we put the vias on the BGA pad, you must first do plug hole, and then gold-plated, easy to BGA welding The
(B) to avoid the flux residue in the vias;
(C) the electronics factory surface mount and component assembly is completed after the rigid PCB in the test machine to take the vacuum to form a negative pressure to complete:
(D) to prevent the surface of the solder paste into the hole caused by Weld, affecting the placement;
(5) to prevent the wave soldering tin beads when the pop-up, resulting in short circuit.