AN1902 Freescale Semiconductor / Motorola, AN1902 Datasheet - Page 18

• Manufacturer Part Number: AN1902
• Description: Quad Flat Pack No-Lead (QFN)
• Manufacturer: Freescale Semiconductor / Motorola

AN1902/D
18
5.2.4.2 X-Ray Inspection
X-ray is one way to detect solder shorts underneath the QFN package. X-rays trans-
mitted from the X-ray tube are absorbed by the components in proportion to their den-
sity. In this case, solder joint having a higher density absorbs most of the X-rays and
the resultant X-ray intensity is detected and interpreted in gray scale image as shown
in the photo in
voids in the exposed pad region.
Freescale Semiconductor, Inc.
For More Information On This Product,
Quad Flat Pack No-Lead (QFN)
Figure
Go to: www.freescale.com
Figure 21 Optical Photos of QFN Solder Joints
Figure 22 X-Ray of 9x9 mm QFN Package
22. The X-ray image is also a good instrument to view solder
Punch Singulated Version
MAP QFN “E” Version
MAP QFN “S” Version
MOTOROLA