The reballing of BGAs come with some challenges and therefore should not be attempted by inexperienced users unless properly trained-especially in the case of sensitive devices, expensive components or very high ball count components. BEST is knowledgeable in IEC TS 62647-4 standards for the restoration of BGAs, In addition cleanliness standard testing, ball shear testing, co-planarity testing and XRF testing are services BEST can perform post BGA reballing.
Each of these problem areas may be mitigated by either having properly trained personnel or by using a professional contract rework facility such as BEST perform the work.
An ion chromatograph (IC) is the most common tool for precision testing of device cleanliness. This method can quantify and identify specific ionic species that are present on an electronic component or board. The most common test method followed is the IPC TM-650 2.3.28. The device is placed into an ionically-clean bag (e.g. Kapak), and is immersed in an extract solution of 75% isopropyl alcohol (IPA) to 25% de-ionized water. It is important to be sure that the sampling procedures do not introduce any ionic contaminates. The PCB is extracted in the solution for one hour at 80 degrees centigrade, the resulting extract is then injected into the ion chromatograph. The IC then separates and detects each individual ion for which it was calibrated. Click here to see an Ionic Cleanliness testing report (PDF).