One of the most difficult tasks related to printed circuit board (PCB) assembly or repair is reworking a ball grid array (BGA). The reason for this is due to the peculiar nature of BGAs: They are made to permanently bond the PCB and its accompanying integrated circuit, making it nearly impossible to reach the connecting pins or heat the entire device to the solder’s melting point without potentially damaging it.
The fact that the tin solder balls, the “ball” in the ball grid array, become unstable due to the continual heating and shrinkage of the board or its components as induced by the typical heating cycle of the board is one of the most frequent reasons for BGA repair and rework.
Although the techniques for BGA rework are established, several rework problems and errors can occur during a regular BGA repair or rework, necessitating either a series of expensive repairs or the need to discard the BGA and start over completely. So it is important that you select the top BGA rework services provider to ensure you get your equipment back in the best condition and save from extra costs.
What Are Some Typical Reasons For BGA Rework Errors?
The following summary makes it simple enough to understand how the process should work, yet mistakes still occur. The following are a few of the most typical ways a BGA repair goes wrong:
A Lack Of Operator Training
BGA repair specialists must have a solid education and a well-honed skill set. Understanding the materials they are working with, the way they interact, and how their tool choice may affect this is a necessary component. A significant portion of this is having a thorough understanding of the BGA repair procedure and the ability to assess probable repair situations before work is done.
Even though the repair procedure sounds straightforward, there are a few details to keep in mind when it comes to BGA repair, and a repair specialist must be aware of these details before beginning a BGA repair.
The likelihood of thermal mismatch among the PCB and BGA, the potential for solder heat to liquefy other components, as well as proper thermal and flow management techniques are just a few things technicians need to be aware of.
Improper Planning
The technician’s preparation is the key to a task that lasts long, whether a straightforward rework or a comprehensive BGA repair. As the process explains, a lot of groundwork goes into a proper BGA job, and understanding that your technician is taking those measures can be reassuring.
The technician needs to conduct research and make judgments long before they even attempt to touch the BGA. They must accurately gauge the solder ball size of the BGA in order to ensure that they are utilizing the appropriate size, and they have to verify aspects like the coplanarity of the solder balls with the rest of the device. After conducting this research, the technician can decide on a few things, including whether to utilize solder paste, what they believe to be the best stencil, and selecting the proper alloys and chemistry to guarantee success.
A good technician can perform several things before a repair that can make or break it after they’ve done their research and made their selections, including:
- Evaluating solder mask damage
- Examining the PCB site for contamination or missing pads
- Getting ready procedures, including baking the PCB and BGA’s moisture and removing or otherwise protecting heat-sensitive components to guard against damage or reflow
Choosing The Wrong Equipment Or The Wrong Materials
This ties along with the preceding argument regarding insufficient planning; however, as the saying goes, you need the correct tools for the job. The means a technician employs to resolve BGA rework problems must be adaptable, capable of carrying out particular jobs, and able to withstand repeated use in a controlled procedure.
A technician must select the best equipment for the work as well as the appropriate tools. Purchase machinery that offers you a range of capabilities and choices, such as closed-loop thermal detection and control and the capacity to supply heat as and when the process calls for it. Ensure your tools allow you to manipulate products as required for both the removal of parts and their replacement.
Some of the BGA rework concerns you might see in the future can be minimized by using the highest quality tools available and not by scrimping. Solder junctions voided by too much solder are one of the BGA rework problems that can be avoided with the right material selection and equipment choice. A BGA may need residual solder cleaned, and the process restarted if the solder joint voiding is greater than 25% due to the incorrect type of solder paste for the substances in question. Other options include outright rejecting the problematic BGA or performing more rework, particularly if this threatens the solder attachment sites.
Damage From Collateral Heat
One of the consequences of your chosen materials’ incorrectly profiled thermal qualities is collateral heat harm. Collateral heat damage, as its name suggests, harms neighboring components and, subject to which component was harmed and how, produces a variety of other BGA rework problems.
In addition, problems such as pad and lead damage, solder oxidation, and starved junctions can arise when solder from surrounding components reflows after setting, all of which can expose you to additional issues as time goes on.
Conclusion
Always hire an industry expert when it comes to addressing BGA rework and repair. BGA Repair services that specifically cater to your needs. BGA rework and repair with the right equipment, well qualified and trained technicians that help with troubleshooting and preventative maintenance.