PCBA Tech - What are the BGA welding quality and inspection methods

If we compare a fully operational PCBA to a person, then the core command center or brain must be BGA. Then the quality of the BGA soldering directly determines whether the PCBA can operate normally, whether it is paralyzed or has a stroke. It depends entirely on whether the BGA soldering can be accurately controlled during the SMT patch processing. The subsequent inspection can detect the soldering. Issues and properly handle related issues.

What are the methods of BGA welding quality and inspection

First of all, the welding of BGA is not like a resistance-capacitance component. It is only necessary to align the welding to prevent false errors and omissions. The soldering of BGA is that the solder joint is under the chip, and the position of the PCB circuit board is corresponding to the densely distributed solder ball, after the SMT soldering is completed. Ordinary people look like a black square, and it is opaque, so it is very difficult to judge with the naked eye whether the internal welding quality meets the specifications.

What are the methods of BGA welding quality and inspection

It's like people feel sick, but don't know where the problem is? When we go to the hospital, the doctor can't confirm the lesions inside our body. At this time, we need to do X-ray scan or CT/MRI. In the same way, for BGA testing without testing equipment, we can only look at the outer ring of the chip first, just like Chinese medicine first: "look, smell, ask, and cut". Check whether the collapse of each position is the same during solder paste soldering, and then align the chip with the light to check it carefully. Then adding each row and each column can transmit light and display. At this time, we can roughly eliminate the problem of continuous soldering. But if you want to judge the quality of the internal solder joints more clearly, you must use X-ray.

What are the methods of BGA welding quality and inspection

X-ray is the CT scanner we will use when we go to the hospital. Its advantage is that it can be used to directly inspect the inside of the circuit board by X-ray without disassembly. It is a commonly used equipment for PCBA processing plants to check BGA soldering. The principle is to layer the solder balls through the internal line fault of the X-ray scanning surface to produce a tomographic effect, and then layer the BGA solder balls to produce a tomographic effect. The X tomographic photos can be compared according to the original CAD design data and the user setting parameters, so that the conclusion of whether the welding is qualified or not can be drawn in a timely manner.

What are the methods of BGA welding quality and inspection

Its advantage is that it can not only check the BGA option, but also check the solder joints of all packages on the PCB circuit board, which can realize multiple functions in one machine. But its shortcomings are also very obvious, one: high radiation, long-term use is not beneficial to employees. Two: The price is too expensive.