Proper BGA Repair Processes
Bake Printed Circuit Board – Ball Grid Arrays to be removed and reballed must be “dry” prior to removing them from a Printed Circuit Board. The chip can be “dried” by baking the entire printed circuit board per JEDEC standards (usually 125 Degrees Centigrade for 24 hours)( or lower and longer if the Printed Circuit Board is also to be salvaged and other components on the PCB will not tolerate 125 Degrees C). This removes moisture from the chip (and printed circuit board) and eliminates the risk of “Popcorning” the internal dye of the Ball Grid Array. If baking is not performed and chip does “Popcorn”, the chip to be salvaged may be damaged. If “Popcorn” damage does occur, the Ball Grid Array is not repairable. “Popcorning” is often not visible to the naked eye and may only become apparent once the chip is placed back in service.
Remove Ball Grid Array – XModdz uses the most advanced BGA rework equipment for Ball Grid Array removal. The BGA removal process is performed using custom thermal profiles for each Printed Circuit Board and BGA Location. Manufacturers guide lines are observed and our operators are trained to spot potential problems during the Ball Grid Array removal process.
Bake Ball Grid Array – Ball Grid Arrays must be “dry” before our BGA reballing service can be attempted. BGAs that were removed from “just baked” boards do not need to be re-baked if the BGAs have not been subjected to moisture or humidity that exceeds their moisture rating after being removed from the printed circuit board. Ball Grid Arrays that have been exposed to moisture in excess of their manufacturers’ moisture rating are baked 24 hours at 125 Degrees Centigrade to “dry” the BGA.
Site Dress Ball Grid Array – XModdz site dresses BGAs manually and under a microscope. Our operators remove the existing solder and clean the surface. Great care is taken to prepare the chip to condition that is similar to the BGAs original condition prior being originally balled.
BGA Inspection – XModdz carefully inspects each BGA to be reballed under a microscope. We look for anything that might interfere with XModdz “superior” BGA reballing results.
Paste High Temperature Ball Grid Array – Pasting is generally only required on High Temp Ball Grid Arrays to create a fillet around the High Temperature Solder Spheres (Usually Pb90/SN10) that do not themselves reach reflow temperature during the BGA reballing process.
Place BGA Solder Spheres – XModdz internally aquires custom tooling for the application of solder spheres on Ball Grid Arrays. This gives XModdz unique flexibility within the industry to accommodate customer BGA reballing requirements down to .4mm pitch arrays, interstitial, mixed pitched arrays, non-standard arrays, and to provide quick turn BGA reballing of small quantities as well as expeditiously and cost effectively reball production quantities of greater than 10,000 pcs. We use top quality, high tolerance solder spheres in our BGA reballing process. We stock both standard and metric size solder spheres in Lead and Lead Free. We routinely have more than 5 million spheres in stock to quickly meet our customers BGA reballing needs.
Reflow Ball Grid Array – At XModdz, we use a full BGA equipment to reflow ball grid arrays during the reflow process. Temperature profiles are created with Ball Grid Array manufacturing guidelines in mind. In fact, BGA reballing reflow process temperatures generally are cooler than temperatures used for the same chip to be reflowed back on a printed circuit board. The lower temperatures result from the fact BGAs being reballed are exposed on both side of the chip rather than one side down on a printed circuit board as during a PCB build. Also the fact that only the mass of the reballed Ball Grid Array need be brought to reflow temperature helps lower necessary reflow temperatures.
BGA Reball Inspection Process – each individual reballed BGA is inspected after leaving the reflow process under magnification for adequate reflow, co-planarity, bridged spheres or anything that might interfere with XModdz’s “superior” BGA reballing results.
Clean/Wash Reballed BGA – a combination of manual applied pressure, Isopropyl Alcohol and water are used to clean the reballed BGA to a like new cleanliness and appearance. Ultrasonic Cleaners are used for heavily soiled BGA chips. Acetone in some cases is also used.
BGA Reball Inspection Process – each individual reballed BGA is again inspected after leaving the cleaning and washing process. XModdzs operators inspect under microscopes for cleanliness as well anything that might interfere with XModdzs “superior” BGA reballing results.
Bake and mark Reballed BGA – Depending on the process and chemistry used, reballed BGA’s are re-baked at 125 Degrees Centigrade to ensure that the Ball Grid Arrays are “dry” and ready to encounter reflow temperatures during a Printed Circuit Board manufacturing process. When time is of the essence, XModdz is also able to quickly reball ball grid arrays with same day service on small quantities of reballed ball grid arrays using no-clean chemistry and in house cleaning methods.