Additional Information
17 of 20
Revision 6.0
2020-11-12
Recommendations for Board Assembly of Infineon Quad Flat
Packages
Rework
6
Rework
QFP components are in general reworkable. Single solder joint repair of small pitch terminated packages can,
however, be very difficult and is not recommended. The reuse of completely de-soldered components is not
recommended. The de-soldered components should be replaced by new ones.
A rework process is commonly done on special rework equipment. There are various systems available that
meet the requirements for reworking SMD packages. All handling guidelines discussed in this document have to
be respected. Special focus should be on the following items:
Due to the decreased automation level given by the general rework approach, even higher care compared to
standard assembly must be taken. Tools that do not damage the component mechanically have to be
chosen. Mechanical forces that do not necessarily cause visible external damage can still cause internal
damage that reduces the component’s reliability. A proper handling system with vacuum nozzle may be the
gentlest process and is therefore recommended. However, the impact of rework tools has to be assessed
properly. In general, more manual handling increases the effort for documentation, training, and monitoring
of the rework process(es).
During rework, special care must be taken concerning the proper moisture level of the component
according to the J-STD-033. Drying the PCB and the component prior to rework might be necessary.
A proper drying procedure for SMD packages is described in the international J-STD-033 standard [5].
Please also refer to the recommendations of your PCB manufacturer and take all specific needs of
components, PCB, and other materials into account.
Whatever heating system is used (hot air, infrared, hot plate, etc.), the applied temperature profile at the
component must never exceed the maximum temperature according to the J-STD-020 standard. Depending
on the specific heating profile used during rework, components adjacent to the mounting location might
also experience a further “reflow run” in terms of the J-STD-020 standard [4]. Internal investigations have
shown that the temperature profile must be recorded.
If a device is suspected to be defective and a failure analysis is planned, Infineon usually expects customers to
desolder the component prior to return to Infineon. The component shall be returned in a proper condition
according to the original package outlines.
In some special cases such as solder joint inspection Infineon may request that the PCB or part of the PCB with
the component still attached should be sent to Infineon.
Note:
Before returning a device for failure analysis at Infineon, please clarify the return condition of the
suspected component (ie onboard or desoldered) with the Infineon Application Engineer or
Customer Quality Manager who supports your company.
For further information about component rework on PCB, please refer to the
General Recommendations for
Board Assembly of Infineon Packages
document that is available on the Infineon web page [1]. Please also feel
free to contact your local sales, application, or quality engineer.
