TEST REPORTDYE AND PRY EVALUATION

Prepared for:

Prepared by:BEST, Inc.

3603 Edison PlaceRolling Meadows, IL 60008

Best Job NumberDate Testing CompletedSamples Submitted 10 PCBs

Requested ServicesBEST, Inc. was asked to perform “dye and pry” analysis on the BGA devices of ten assemblies. The PWAs were visually and x-ray inspected. There were no abnormalities noted from the visual inspection. The x-ray inspection indicated some voiding of the TI BGA.

Dye and Pry ProcessThe procedure for this analysis includes immersing the subject device in a red dye under a vaccuum. The volitile components of the dye are then driven off by baking. The device is then pryed off the board. If there were any cracks or other types of solder interconnect failures, the areas will exhibit red dye penetration.

ResultsThere was no evidence of any dye penetration at the interconnect between the ball and the pad on all of the BGAs that were processed.

What was seen was a great deal of solder voiding of the TI device at the solder ball to BGA interface. The amount of solder voiding present on the TI BGAs is enough to present a high risk of failure. The failure of the solder interconnect will probably occur after thermal cycling or mechanical stresses. The solder voids are a defect in accordance with IPC-A-610 revision D, class 2 (paragraph 8.2.12.4).

RecommendationThe root cause of the solder voiding has to be identified. This may be caused by the thermal profile needing adjustment, or from the use of different alloys. Further research is necessary.

Illustration 1: Serial #1210, Board, TI BGA, solder voids (light spots in solder balls)

Illustration 2: Serial #1210, Board, TI BGA, solder voids (light spots in solder balls)

Illustration 3: Serial #0216, Board, TI BGA, no dye penetration

Illustration 4: Serial #0362, Board, TI BGA, solder voids (on top of solder ball)

Illustration 5: Serial #0362, BGA, TI BGA, solder voids

Illustration 6: Serial #0362, BGA, TI BGA, solder voids (100X magnification)

Illustration 7: Serial #1262, Board, Samsung BGA, no observed problems

Illustration 8: Serial #1262, Board, Samsung BGA, no observed problems (50X magnification)

Illustration 9: Serial #1262, BGA, Samsung BGA, no observed problems

Illustration 10: Serial #1262, BGA, Samsung BGA, pads ripped from board

Tested by: ____________________________ Date: ______________Hung HoangOperations Supervisor

Approved by: ____________________________ Date: ______________Bob WettermannPresident