{"id":253,"date":"2012-06-20T13:59:59","date_gmt":"2012-06-20T13:59:59","guid":{"rendered":"http:\/\/Ascenten.net\/tech-notes\/?p=253"},"modified":"2018-10-26T12:50:45","modified_gmt":"2018-10-26T12:50:45","slug":"x-ray-inspection-of-a-bga","status":"publish","type":"post","link":"https:\/\/ascenten.net\/tech-notes\/x-ray-inspection-of-a-bga\/","title":{"rendered":"X-Ray Inspection of a BGA"},"content":{"rendered":"

Ease or Dis-Ease<\/span> of Miniaturization<\/strong><\/h2>\n

In today\u2019s world, miniaturization may be the holy grail of success in designing and building certain portable electronic equipment. A mobile phone is expected to substitute a laptop in functionality without growing a bit in size and weight. Many times design engineers can face an arduous task of increasing product features while reducing form factor and may need to use miniaturized BGA packages when available. For many types of ICs, such as FPGAs and high performance processors, BGA is the only package choice available these days.<\/p>\n

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However, a BGA cannot be hand-soldered and a manual pick and place machine may not be able to handle this chip. In most cases soldering BGAs require use<\/span> of expensive assembly lines. Again with very<\/span> high pin count BGAs, there is always that lingering doubt of<\/span> whether all the pins are in proper contact with the PCB.<\/p>\n

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A bad contact or a missing ball is not easy to detect with laboratory optical equipment. An electrical test of the entire circuit may show good connectivity, but in long run<\/span> a power-intensive system could fail.<\/p>\n

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How do we do a precise inspection of BGA solder quality? The answer is, using X-ray inspection.<\/p>\n

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X-ray Inspection Systems, Procedures and Results<\/strong><\/h2>\n

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\u00a0An X-ray inspection system<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

An X-ray inspection system consists of an X-ray chamber in which an electronic board is placed and an X-ray camera that produces X-ray images of the inspected BGA IC on to an interfaced computer.<\/p>\n

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The X-ray camera moves in a grid pattern across the entire BGA under inspection inside the chamber. Such an inspection system meticulously unearths solder joint shorts, opens and voids of the inspected BGA by shade variance of balls. As observed in the image below of a typical BGA X-ray scan,\u00a0the dark round balls indicate well connected and well soldered balls.\u00a0The balls which looks<\/span> very light indicate imperfectly soldered BGA balls.<\/p>\n

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The image below of an 80-pin BGA shows the outcome of the X-ray scan done on a board manufactured by Ascenten. Here the clean round black patterns indicate proper soldering of the BGA balls.<\/p>\n

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A closer inspection of the above image infers<\/strong>–<\/p>\n

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