Ball Grid Array (BGA) components have become ubiquitous in present-day hardware due to their high pin count and compact plan. In any case, the underneath grid of solder ball connections too, makes BGA chips exceptionally troublesome to adjust when faults happen. Proper BGA rework procedure is fundamental to securely remove and replace BGAs without harm. In this article, we shall talk about the entire process of BGA rework.
What is BGA rework?
Rework BGA is the method of removing and replacing a BGA component on a printed circuit board (PCB). This can be ordinarily done for two primary reasons:
- When a BGA component breaks down or is damaged, it may have to be replaced to reestablish the usefulness of the PCB.
- In some cases, a BGA component ought to be updated or replaced with a distinctive component due to plan changes or improvements.
Equipment
The important tools for professional rework BGA method are:
- A BGA Rework Station is a machine used for fixing and working on BGA components. A special workstation has precise temperature control and tools to reach underneath BGAs.
- The next step is that you need a soldering station for carrying out the process of improving the solder joints. A special soldering iron is required in this case, having a temperature of about 450 Celcius for fixation.
- The next is simple and is known as rebelling. You need to recall the new solder balls using a lead-free solder paste called sac 305 and make sure it matches the solder alloy to that of the board. Also, make sure that the solder balls are of the right shape and size.
- After the repair, x-ray imaging shows that the solder joint under the BGA is formed correctly.
BGA Rework process
- Make sure to have a safe environment by using a wrist strap that is connected to the workstation. Clean the board very well around the BGA area using isopropyl alcohol. Put liquid flux on the edges of the BGA on the surfaces where the solder will stick. Make sure the board is fastened correctly on the rework station and adjust the optics.
- The BGA can be heated and taken out after the flux is used. Now heat the BGA out. For that, place the heating nozzle right below the center of the board and continue to heat the solder until it reaches a temperature of around 250 Celcius. Now, by keeping the temperature steady, the joint will melt off completely. Now, using the picking tool, pick up the BGA slowly and make sure not to damage the pads.
- Clean the pads completely by using a solder wick braid and flux to remove any leftover solder. Look at the pads under a microscope to make sure they are not damaged or lifting. If necessary, use a soldering iron heated to 350°C to add more solder to any raised pads. Use isopropyl alcohol to remove any remaining flux.
- Then, more solder balls are put back onto the BGA pads. Put a small amount of solder paste in the middle of each pad using a mini stencil or a dispenser. Use tweezers to put a new solder ball on each blob of solder paste. Use the same layout pattern for the BGA balls. Make sure that the balls are placed flat on the paste and not on the nearby pads. Once all the locations are repaired, use a heating nozzle that is hotter than 150°C to carefully attach the small round metal balls in their positions without completely melting them again.
- The new BGA can now be adjusted and connected with solder. Place the BGA above the specified area using the pick tool and make sure to align them. Use a microscope to check if all solder balls touch the paste deposits. Put flux around the edges of the BGA chip on any solder that you can see. Use a heating nozzle to connect the component by heating it and keep the heat on until the solder has spread evenly on the pads and the reflow process is finished. Let the assembly cool down before touching it.
- Make sure the connection between BGA components is good after replacing them. Visually check the edges of the building for the correct forming of joints. Use X-ray pictures to see hidden solder connections underneath a container.
- Check if the board is working properly after the BGA rework. If you have a fixture, do in-circuit testing. Boost and enhance the capabilities of a system through physical activity. If available, you should check if the board has any diagnostics, self-test, or functional test routines and run them.
The Conclusion
To conclude, one can easily succeed in their BGA rework, given they use the right tools and follow the protocols strictly. By keeping track of the above pointers, one can go ahead and carry out the BGA rework in terms of upgradation or replacement.
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