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58 SMT007 MAGAZINE I JULY 2026 B all grid array (BGA) devices are ubiquitous in electronic products primarily due to their advantages, including compact packag- ing, greater durability than leaded devices, and improved performance from shorter signal paths. BGAs improve electrical performance by reducing inductance and capacitance between the internal silicon die and the PCB, resulting in superior signal integrity and faster operation speeds. BGAs also offer superior thermal performance by dissipating heat more effectively, reducing the risk of overheating. BGAs provide high density interconnection because, unlike perimeter-only packages such as quad flat pack (QFP) devices, BGAs utilize the entire bottom surface of the device, allowing for a much higher number of I/O connections in a smaller foot- print. However, since the solder interconnections of a BGA are hidden beneath the device, inspecting solder joints is challenging. Solder Joint Inspection Methods A major advantage of BGAs in the PCB assembly process is their ability to self-align during reflow soldering, as the surface tension of molten solder balls helps position the component on the PCB pads. Several methods can be used to inspect BGAs after solder reflow on a PCB, including visual, endoscope, and X-ray inspections. • Visual inspection: Used with an optical mi- croscope to view the outer rows of a BGA for wetting and ball-to-pad alignment BY N AS H B E L L , B EST, I N C. X-RAY INSPECTION of Ball Grid Array Solder Joints K N O C K I N G D OW N T H E B O N E P I L E