With the changing times, BGAs (Ball Grid Arrays) have become widely used. In this context, it’s essential to understand the various types of reballing processes, such as Koses reballing and IC chip reballing. Regardless of the method used for reballing, a BGA reballing machine is necessary. In the reballing process, a reballing stencil is also required. If you are unfamiliar with the BGA reballing process, you can refer to the following operation steps:
- Use a reballing machine to select a reballing stencil that matches the BGA solder pads. Evenly sprinkle the solder balls on the stencil, shake the reballing machine to roll the excess balls from the stencil into the ball collection groove of the reballing machine, ensuring that each hole on the stencil surface retains one solder ball.
- Using the reballing stencil, place the BGA device with pre-printed flux or solder paste on the workbench, with the flux or solder paste facing upwards. Prepare a stencil matching the BGA solder pads, with the opening size of the stencil slightly larger than the solder ball diameter (0.05~0.1 mm). Place the stencil around the BGA device with spacers to ensure that the distance between the stencil and the BGA is equal to or slightly smaller than the solder ball diameter, and align them under a microscope. Evenly sprinkle the solder balls on the stencil, remove the excess balls with tweezers, ensuring that each hole on the stencil surface retains one solder ball. Remove the stencil, inspect, and complete as necessary.
- Manual placement: place the BGA device with pre-printed flux or solder paste on the workbench, with the flux or solder paste facing upwards. Use tweezers or a vacuum pen to manually place each solder ball as if it were a surface mount component.
- Paste-brush method: during template processing, increase the thickness of the template and slightly enlarge the opening size. Directly print the solder paste on the BGA solder pads. Due to surface tension, solder balls are formed after reflow soldering.
- Reflow soldering: perform reflow soldering treatment, and the solder balls will be fixed on the BGA device.
- After the reballing process, clean the BGA device thoroughly and quickly perform assembly and soldering to prevent solder ball oxidation and device moisture absorption.
In summary, the BGA reballing process and the IC chip reballing method are similar. If you are new to the BGA reballing and rework process, practice repeatedly to become proficient, ensuring the perfect implementation of the BGA reballing method.