BGA (Ball Grid Array) chips are precision electronic components, and improper ball attach methods can easily lead to rework failure. Employing the right ball attach method is crucial for enhancing the reliability, safety, and stability of BGA chips. Here are several common methods for BGA ball attach:
- Stencil Ball Attach Method:
- Place the BGA device with pre-printed solder paste or flux on the workbench, with the paste or flux facing upwards.
- Prepare a matching stencil with openings slightly larger (0.05-0.1mm) than the solder ball diameter. Position the stencil over the BGA device, ensuring it aligns properly.
- Evenly spread solder balls on the stencil. Remove excess balls with tweezers, leaving one ball per opening in the stencil.
- Remove the stencil, inspect, and fill any missing balls.
- Reballing Tool Method:
- Select a BGA Reballing tool with a mold matching the BGA pads. The mold openings should be slightly larger (0.05-0.1mm) than the solder ball diameter.
- Sprinkle solder balls evenly onto the mold, ensuring each opening contains a ball.
- Attach the BGA device with pre-printed solder paste to a suction nozzle. Use the adhesive properties of the paste to pick up the balls and place them onto the corresponding pads.
- Inspect the placement and fill any gaps with tweezers if necessary.
- Appropriate Flux Paste Brushing Method:
- When processing the template, increase the template thickness and slightly enlarge the template openings.
- Directly print solder paste onto the BGA pads. Surface tension will form solder balls after reflow soldering.
- Ensure that the solder paste is brushed just right during BGA rework to avoid ball attach failures.
- Manual Attachment Method:
- Place the BGA device with pre-printed solder paste or flux on the workbench, with the paste or flux facing upwards.
- Use tweezers or a vacuum pen to manually place solder balls one by one onto the pads, similar to chip placement.
- This method is suitable for individual craftsmen or small companies. However, it requires high skills from rework personnel and is time-consuming, resulting in lower ball attach success rates.
These are the methods for BGA ball attach, detailing specific operational procedures and four different ball attach techniques. Each individual can choose the method that suits them best. However, it’s recommended to use a combination of a BGA rework station and BGA ball attachment machine, as it ensures higher ball attach success rates and faster speeds.