The determination method for poor soldering of BGA solder balls

Date：2024-01-18 13:50:43Views：96

BGA solder ball welding is a common connection method in electronic manufacturing, but adverse phenomena may occur during the welding process, which can affect the performance and reliability of electronic products. This article will introduce several common methods for determining the welding defects of BGA solder balls, to help readers better understand and solve related problems.

There are basically three ways to check the solderability of BGA, using X-ray, penetration red test, and slicing. Before analyzing the solderability of BGA, it is recommended that you still use X-Ray to check if any issues can be identified, as this is a non-destructive inspection. Only when X-Ray cannot determine the problem can you continue to use the latter two destructive methods.

1、 Using X-Ray to Check BGA Solderability

A typical X-ray inspection machine can only view two-dimensional (2D) images, but it is difficult to detect problems such as empty solder or cracked solder balls in 2D because images can only see the shape of the entire solder ball. However, if there are too many or too large bubbles inside the solder ball, it is highly likely to cause fracture problems. In addition, if the outer diameter of the solder ball is larger or smaller than other adjacent solder balls, there is also a chance of empty solder joints.

In addition, recently there have been new X-ray examination machines that can produce three-dimensional imaging results similar to hospital computed tomography, presenting three-dimensional images and checking for solder defects. However, due to the high cost of these machines, it is not possible for ordinary factories to purchase such equipment. A more feasible way is to rent such X-ray machines from external laboratories for preliminary examinations. If this kind of inspection can detect the problem of poor BGA, there is no need to use it for subsequent destructive testing.

2、 Red Dye Penetration Test

This is a destructive test, usually used on defective boards that cannot be undone by all non-destructive tests, because if the destructive test continues, the board and BGA will have to be scrapped, and even the original evidence may be destroyed. Generally speaking, the red staining test can show the soldering phenomenon of all the tin balls under the entire BGA.

Its theory is to fill the entire BGA with a more obvious amount of red potion, utilizing the characteristic that red potion can penetrate all small cracks. Then, when the BGA is removed from the circuit board, the distribution of red potion and the results of the solder balls are checked. When making a judgment, it is necessary to simultaneously check how much red potion is left on the solder pads on the circuit board and the solder balls remaining on the BGA. The recording method is usually based on a drawing with a table drawn on it, These tables will correspond to the position of BGA solder balls, and then record the residual phenomenon of red medicine on each solder ball.

3、 Circuit board slicing inspection BGA solderability

This method is also a destructive experiment and is more labor-intensive than the dye red test. It usually requires a more accurate pre job analysis, using electrical testing to check which tin ball may have a problem before slicing. You can temporarily imagine slicing as taking a knife to cut from the area you think is problematic, and then examining the cross-sectional structure of the tin ball in detail, Even the circuits and nodes on the circuit board can be seen, and sometimes the BGA problem does not come from the soldering of BGA solder balls, but from the circuit board's circuit problems. Slicing can also be used to analyze the circuit board's problems together.

However, if the mechanical action of slicing is too large or too fast, it is easy to damage the original BGA and the circuit board's circuit connection structure. Therefore, it is necessary to be very careful, slowly grinding out the desired profile step by step, and removing dust and special development from the ground area. Otherwise, some phenomena are not easily detected by the microscope due to its time-consuming and labor-intensive nature, So it usually needs to be sent to the laboratory outside the factory and sliced by a dedicated person.

In practical applications, we need to choose appropriate methods based on specific situations and combine them with other testing methods to ensure the quality and reliability of the product. With the continuous development of electronic manufacturing technology, BGA solder ball welding technology is also constantly improving and perfecting. We believe that in the near future, we will be able to more accurately determine the quality of BGA solder ball welding, providing more reliable guarantees for the development and application of electronic products.