How to Reball a BGA Chip: Step-by-Step Guide

Reballing is the process of replacing the tiny solder balls on the underside of a BGA (ball grid array) chip so it can be reattached to a board. It is a core board-level repair skill,used for power ICs, NAND, CPUs and more. This guide walks through the workflow; take your time and practise on scrap boards first.

Tools you will need

• Hot air rework station and a fine soldering iron
• Solder balls in the correct diameter, and a reballing stencil
• Flux, solder wick (braid) and isopropyl alcohol for cleanup
• Tweezers, and a microscope to inspect alignment

You will find the stations and consumables in our soldering & rework category and tools & supplies. New to microscopes? Read our microscope buyer's guide first.

Step by step

1. Remove the chip and clean the pads. Heat the chip with hot air (around 350-380°C on most lead-free boards), lift it with tweezers, then wick away the old solder and clean both the board pads and the chip with flux and braid until flat.
2. Position the reballing stencil. Place the chip in the correct stencil pocket (or align a universal stencil over it) so every pad lines up with a hole. Clamp or hold it flat so solder balls cannot roll under the stencil.
3. Apply solder balls. Brush or sprinkle the correct-diameter solder balls across the stencil so one drops into each hole. Remove the excess. A little tacky flux helps the balls sit.
4. Reflow the balls onto the chip. Gently heat with hot air from above until the balls reflow into shiny, even domes. Keep the nozzle moving to avoid overheating one corner.
5. Clean and reinstall. Let it cool, lift the stencil, clean the flux residue, then flux the board pads and reflow the chip back into place,checking alignment under a microscope.

Tips for clean joints

• Flux is your friend,under-fluxing is the most common cause of failed reflow.
• Keep the hot air moving so you heat the whole chip evenly, not one corner.
• Inspect every reball under the microscope before reinstalling the chip.