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16 SMT Magazine • May 2014 by alejandro Castellanos, Dr. Zhen (Jane) Feng, David Geiger, and murad Kurwa FlexTroniCS inTernaTional inC. feATuRe abstract Manufacturing technology faces challenges with new packages/processes when confronting the need for high yields. Identifying product defects associated with the manufacturing pro- cess is a critical part of electronics manufactur- ing. In this project, we focus on how to use AXI to identify BGA head-in-pillow (HIP), which is challenging for AXI testing. Our goal is to help us understand the capabilities of current AXI machines. For the study, we used two boards exhibit- ing HIP defects with four types of AXI machines located at four Flextronics sites, or at a vendor laboratory. The AXI machines used have dif- ferent X-ray technologies: laminography and tomosynthesis. We collected three sets of data with AXI 1 machine (laminography), and AXI 4 machines (tomosynthesis); one set of data with AXI2 (tomosynthesis); and four sets data for AXI3 (tomosynthesis). We studied AXI mea- surement data with the different AXI algorithm threshold settings. The data indicated clearly that the Algorithm Threshold settings are very critical for detecting HIP, including open. The defective HIP pins are validated by using 2DX and CT scan. The test data consist of defects escaped %, false call ppm and also gage R&R. The AXI im- ages for HIP pins, false call pins and defects es- caped pins are presented in the paper. The 2DX and CT images are provided for identifying HIP type (shape and size). Introduction More BGA and area array devices are ap- pearing on PCBAs as product and functional complexity increases. Furthermore, to achieve good signal integrity, more I/Os are packed in smaller areas within the available real estate. It is very important to use AXI and other Non-