There may be several reasons for bubbles in BGA welding:
1. There is residual grease or dirt on the surface of the component or PCB. During the welding process, oil or dirt will evaporate at high temperatures to produce bubbles.
2. There is moisture on the surface of the component or PCB. During the welding process, water is heated to evaporate and create bubbles.
3. The welding temperature is too high or the welding time is too long. If the welding temperature is too high or the welding time is too long, the volatile substances in the solder may create bubbles during the welding process.
4. Composition or quality of solder. If the composition of the solder used does not meet the requirements or the quality of the solder is problematic, it may also lead to the production of bubbles.
To avoid bubbles in BGA welding, you can take the following measures:
1. Clean components and PCB surfaces before welding to ensure there is no residual grease or dirt.
2. Control the humidity of the welding environment to prevent moisture from entering the welding area.
3. Strictly control the welding temperature and welding time to ensure that the welding is carried out within the appropriate range. 4. Use the solder that meets the requirements and ensure the quality of the solder is reliable.
In short, by controlling the conditions of the welding process and selecting the appropriate materials, the bubbles in BGA welding can be effectively prevented.