Remedy for BGA Pad Peeling Off

1. Flatten the front plug hole: Suitable for single-side exposure or partial exposure of the solder mask at the BGA plug hole. If the diameter of the two plug holes differs by 1.5 mm, this process is used regardless of whether the solder mask is covered on both sides.

2. Solder resistance plug hole: Applied to boards covered by solder mask on both sides of the BGA plug hole.

3. Plug holes before and after leveling: Used for thick copper foil boards or other boards with special requirements.

1. Clean the area to be repaired.

2. Remove the failed pad and a small piece of wire.

3. Use a knife to scrape off residual glue, stains, or burned materials.

4. Scrape off the solder mask or coating on the connection.

5. Clean the area.

6. Apply a small amount of liquid flux to the connection area of the board, tin the area, and clean it. The overlap length of the solder connection should be less than twice the wire width. Then, the connection of the new BGA pad can be inserted into the via hole of the original BGA pad. Remove the solder mask of the via hole and treat it appropriately. The new pad area on the board surface must be smooth. If there are exposed inner board fibers or deep scratches on the surface, they should be repaired first. The height of the replaced BGA pad is critical, especially for eutectic solder ball components. Remove the solder mask material between the BGA pad and the board connection or via hole to maintain a low profile. If necessary, lightly grind into the board surface to ensure that the height of the connection does not affect the replaced components.

7. Choose a BGA replacement pad that is closest to the pad to be replaced. A special size or shape can be customized if needed. These new BGA pads are made of copper foil. The top surface of the copper foil is tin-plated and the bottom surface has adhesive bonding pads.

8. Before trimming the new pad, carefully scrape off the adhesive bonding sheet in the solder joint connection area on the back of the new pad. Scrape the resin substrate only from the solder joint connection area. This will allow soldering of exposed areas. When handling replacement pads, avoid fingers or other materials contacting the resin substrate, which may contaminate the surface and reduce the bond strength.

9. Cut and trim the new pad. It can be cut from the tinned side, and the length of the cut should ensure the maximum allowable solder connection overlap.

10. Place a piece of high-temperature tape on the top surface of the new pad, position the new pad on the surface of the PCB, and use the tape to help locate it. The tape remains in place during bonding.

11. Choose a bonding tip suitable for the shape of the new pad. The tip should be as small as possible but should completely cover the surface of the new pad.

12. Position the PCB to make it stable. Gently place the hot soldering tip on the tape covering the new pad. Apply pressure as recommended in the manual of the repair system. Note: Excessive bonding pressure may cause spots on the PCB surface or cause new pads to slip out of position.

13. After the fixed bonding time, lift the soldering iron and remove the tape used for positioning. The replacement pad can then be inspected and cleaned after bonding. Clean the area carefully and check that the new pads are properly positioned.

14. Apply a small amount of liquid flux to the overlap area of the solder connection, and solder the connection of the new pad to the circuit on the PCB surface. Use the least amount of flux and solder to ensure a reliable connection. To prevent excessive solder reflow, tape can be placed on the top surface of the new pad.

15. Apply mixed resin to the overlap joint of the solder connection. To cure the resin, use the maximum recommended heating time to achieve the required resin curing performance. The number of reflow cycles that a repaired BGA pad can withstand depends on the repair materials and process conditions. In addition, resin may be applied around the new pad as an additional bonding aid.

16. Apply surface coating as required.