The so-called trailing hole is a kind of hole defined by the author. It refers to the misalignment between the layers of the HDI plate, so that there is no copper at the bottom of the micro-blind hole, and the laser hole drills the hole of the tail. During welding, the organic matter contained in the pores vaporizes, forming a large-sized tailed hole in the weld.
When the Pcb is manufactured, the orifice plate is misaligned, and a deep HDI hole is formed during laser drilling, since the hole is relatively small. Deep and irregular, it is easy to leave electroplating and cleaning fluid. When the board is welded, it will form high-pressure gas when it encounters high temperature, which will form a large cavity in the BGA solder joint.
What is the treatment method for the BGA trailing hole?
1. On-site: 105°.5 hours drying
2. PCB manufacturing: enhanced process control
The standard for allowing the bottom temperature to be 901° collapse should be removed from the standard.