Sometimes there may be issues with poor BGA soldering during PCBA processing. If there is a problem with the soldering of a certain BGA, the entire board will have problems, and BGA repair must be carried out at this moment. Below, the editor will share with you how to do BGA repair well in PCBA processing.

Four ways to do BGA maintenance well in PCBA processing:

1、 Formal attire method (using ball placement work clothes)

1. Place the cleaned and flat BGA solder layer onto the BGA support platform at the bottom of the ball placement fixture.

2. Prepare a small template in advance that matches the BGA solder layer. The opening size of the template should be 0.05-0.1mm larger than the diameter of the solder ball. Install the small template on the structure of the clamping template on the top of the ball placement fixture, and point and fix it to the solder layer of the BGA device below.

3. Place the BGA printed with paste like flux or solder paste on the BGA support platform at the bottom of the ball placement fixture, with the printing facing upwards.

4. Move the template to the top of the BGA (the position pointed to in front), evenly toss the solder balls onto the template, shake the ball placement fixture to ensure that the surface of the template contains exactly one solder ball per standard hole plate, and use tweezers to remove unwanted solder balls from the template.

5. Remove the template

6. Check whether there is a lack of solder balls on each solder layer of BGA devices, and if effective tweezers are used, make up for the solder balls.

2、 Manually attaching solder balls

1. Place the BGA device printed with paste like solder flux or paste on the workbench, with the solder flux or paste facing upwards.

2. Like SMT patches, use tweezers or a suction pen to place solder balls one by one into the pre printed solder paste or solder joints.

3、 Directly print appropriate solder paste and generate solder balls through reflow soldering

1. When processing SMT templates, increase the thickness of the template and slightly enlarge the opening size of the template.

2. Printing solder paste.

3. Reflow welding. Due to the effect of interfacial tension, solder balls are generated after welding.

4、 Reflow soldering

Follow the instructions in the previous section on BGA rework process for reflow soldering. When soldering BGA devices, the solder balls should face upwards and the amount of warm air should be minimized to prevent the solder balls from being blown and moved. After reflow soldering, the solder balls are fixed on the BGA devices. Reflow soldering can also be performed in a reflow soldering furnace, with a soldering temperature slightly lower than that of reflow soldering on the assembly board by 5-10 ℃. After the reflow soldering process, the BGA devices should be cleaned up and the chips and soldering should be done as soon as possible to prevent solder ball oxidation and device moisture regain.

Among the four ball placement methods mentioned above, the formal method (using ball placement fixtures) has the best effect; Inverted method (using ball placement equipment) is the application of BGA device packaging form, because the size accuracy of solder balls purchased from solder paste manufacturers is weak, resulting in some solder balls with smaller diameters not being able to be activated by mud like flux or solder paste; The effect of manually patching and welding material balls is very low; The method of directly printing star solder paste and producing solder balls through reflow soldering is very simple, but the density of these solder balls is not very good and they are very prone to cracking.