BGA Reballing: Remove, Re-ball and Reflow Safely
BGA components hide their solder contacts under the package, so they can only be worked with hot air and a clean temperature profile. This guide explains removal, reballing with a stencil and solder balls, and controlled re-seating at the rework station.
View rework equipmentHow do you remove a BGA cleanly?
Removal starts by preheating the board from below so the PCB does not warp and neighbouring parts survive. Above a preheat zone of roughly 150‑180 °C the hot-air nozzle runs the actual profile until every ball under the BGA reflows at the same time. Only then is the device lifted straight up with a vacuum pick.
A bottom heater (IR or convection) is mandatory. Without it the top heat would have to rise so high that delamination and popcorning become likely. A type-K thermocouple at the solder joint delivers the real temperature and makes the profile repeatable.
- Preheat from below to keep warpage and delta-T across the board small.
- Place the thermocouple at the ball field and record the actual profile.
- Lift the part vertically only after full reflow, never pry it off.
- A removed BGA is single-use unless it is reballed.
What exactly happens during reballing?
Reballing removes the old solder from the pad field and applies a fresh, uniform ball array. First the residual solder is wicked away with desoldering braid and flux until the pads are flat and clean. Then a reballing stencil positions the new solder balls precisely into every cell of the grid.
- Match the alloy: SAC305 (lead-free) or Sn63Pb37, never mix them.
- Apply flux thin and even so the balls grip the pads.
- Clean residues after reflow and inspect the balls visually.
- Correct missing or merged balls before placing the device.
How do you achieve a controlled re-seat?
Re-seating is done at the rework station with optics or a split-prism that show device and landing area at once. The ball field is aligned exactly over the pads before the reflow profile starts. Self-centring of the melting balls corrects small offsets but does not replace a clean coarse alignment.
The solder profile follows four phases: preheat, soak (flux activation), reflow above liquidus and controlled cooling. For lead-free SAC solder the peak is typically 235‑245 °C and the time above liquidus (TAL) sits at 45‑90 seconds.
Frequently asked questions
Why can a removed BGA not simply be re-fitted?
After removal the balls are uneven or partly left on the board. Without a fresh, uniform ball array the contacts stand at different heights and some joints stay open. That is why reballing is required.
Which solder alloy do I use for reballing?
Follow the original design: lead-free SAC305 melts around 217‑220 °C, leaded Sn63Pb37 at 183 °C. Never mix alloys, or the melting point and joint strength suffer.
Do I really need a bottom heater?
For reliable BGA rework, yes. The bottom heater brings the assembly evenly to preheat, lowers delta-T and prevents board warpage and thermal shock to neighbouring parts.
How do I inspect the joints under the BGA?
Only the outer balls are visible with an endoscope. Inner joints, voids and shorts are shown reliably only by X-ray inspection per IPC-7095 and IPC-A-610.
Looking for a rework station and reballing supplies?
We supply hot-air rework systems, bottom heaters, reballing stencils and solder balls in lead-free and leaded alloys - matched to your assemblies.
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Repeatable solder profiles with thermocouple and bottom heater.
Standards-based
Processes per IPC-7095 and J-STD-033.
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Stencils and solder balls in matching pitch and alloy.
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