Circuit Technology Center recently introduced a new circuit board modification service to accommodate changes required at BGA component sites to address design errors or updates that mandate changes to the circuit board layout.

This refined and tested procedure provides design engineers with an alternative to costly redesign and remanufacture of the assembly. This time-saving process can be implemented at any point in the assembly process saving valuable time and money.

This method effectively changes circuit paths at a BGA sites to meet new or modified circuit patterns. The steps follow.

1. Step 3. Machine a shallow groove in the board surface from the BGA pad area to the perimeter of the BGA site.

   The BGA component and any other impeding components at the site requiring modification are removed and the area is cleaned and prepared.
   
   
2. The short conductor (dog bone) connecting the effected BGA pad to the connecting via is cut using a precision milling system. The existing BGA pad is then removed.
   
   
3. A precision high-speed milling machine with carbide milling cutters is used to machine a shallow groove in the board surface from the BGA pad area to the perimeter of the BGA site. This often requires using a zigzag pattern to avoid nearby surface conductors and features.
   
   

4. Step 5. After the new BGA pad is bonded in place, a copper conductor is soldered to the extending circuit.

   A replacement BGA pad is thermally bonded in place at the original location.
   
   
5. A specially designed copper conductor is positioned within the machined groove in the circuit board surface and one end is soldered to the replaced BGA pad.
   
   
6. The top and sides of the replaced conductor are coated with epoxy leaving the extending end exposed. The epoxy is then cured and the board is cleaned as necessary.
   
   
7. The end of the new conductor extends beyond the perimeter of the BGA site to allow for the soldering of a jumper wire to complete electrical circuit to the new modified location.

   Step 7. The end of the new conductor extends beyond the perimeter of the BGA site to allow for the soldering of a jumper wire.

For more information on this process and other leading edge circuit board repair and rework services visit http://www.circuitrework.com/guides/6-2-1.shtml.