Ball Grid Array

Ball grid array (BGA) is a surface-mount packaging technology consisting of an array of solder balls on the underside of a chip package. BGA has been developed in response to the trend in the semiconductor industry towards the miniaturisation of ICs, and in pursuit of higher integration, higher density, and improved functionality.
BGA makes high density and efficient use of the printed circuit board (PCB) possible. This is because the entire underside of the chip package can be used for connectivity as opposed to wire bonding or quad flat pack (QFP) where connections are only made around the periphery of the chip. Additionally, solder balls provide shorter connections which reduce signal inductance, resulting in less noise voltage and thus improved performance. For BGA to be properly soldered, a precise amount of heat needs to be applied so that each ball in the grid adequately melts and a good quality connection is made. The aim of BGA inspection is to detect and isolate defects that originated during the manufacturing process such as voids or badly soldered balls and their causes.
  • TESCAN systems offer a wide range of possibilities for inspection and failure analysis of BGA packaging.
  • The TESCAN EBIC detector can be used for electrical tests. More rigorous tests require the analysis of the solder balls themselves.
  • The TESCAN BSE detector provides high contrast which makes intermetallic compounds and under-bump metallurgy layers clearly visible. The inspection and characterisation of solder ball junctions in BGA are crucial tasks to determine the reliability of an integrated circuit attached to a PCB and critical in determining the quality of the soldering process and when identifying the cause of the failure.
  • TESCAN Plasma FIB-SEM systems (FERA3, XEIA3) allow solder balls, which can have diameters of up to hundreds of microns, to be effortlessly cross-sectioned in an unrivalled short time frame.
  • Additionally, 3D microanalysis (3D EDX, 3D EBSD) of whole solder balls, for revealing voids, brittle fractures, die cracking or dendritic structures, is possible with the ultra-high sputtering rates that only the Xe plasma FIB can offer.
Ball Grid Array
Cross-section of a solder ball with a diameter of 400 μm completed in 4 hours using Xe Plasma FIB and Rocking Stage for a curtaining-free surface