We x-ray each unit to ensure there is no voiding under the bga’s (ball grid array) At times, when processing such a high technology unit, the balls and the pad on the raw printed circuit board, a small amount of moisture or air can become encapsulates within the solder paste. We use a specific “low void” solder paste formulation, and measure the solder paste height prior to population of the units. These quality control measures make sure there will be no latent defects in the final product. As folks can attest, the units they have been using for years are still going strong. After x-ray we use an ERSA scope to check for cleanliness and complete ball collapse as well.
