TN0973 Datasheet, PDF (4/6 Pages) STMicroelectronics – Safety application guide for SPC56EL54xx/SPC56EL60xx family

Considerations on SPC56EL54xx/SPC56EL60xx package and soldering procedures
TN0973
2
Considerations on SPC56EL54xx/SPC56EL60xx
package and soldering procedures
2.1
Introduction
SPC56EL54xx/SPC56EL60xx package is composed by Ultra Low Alpha mold compound.
Measurements report an alpha particle emissivity of 0.00383 ± 0.00056 cp/h/cm².
This value has been used in the SPC56EL54xx/SPC56EL60xx quantitative safety analyses
(see SPC56EL54xx/SPC56EL60xx FMEDA).
In order to ensure that this value does not increase when soldering the device on a board, a
risk analysis is made in the following chapter. The conclusions of this analysis report that
some caution must take during soldering process in order to avoid package delamination,
hence avoiding any contamination from the soldering material to the silicon contained in the
plastic package.
2.2
2.2.1
2.2.2
2.2.3
2.2.4
Risk analysis
Risk item
Single Event Upset randomly induced by alpha particle emission from Package material
Cause
A possible cause of silicon contamination is the presence of potentially alpha-emissive
soldering material, specifically induced by Pb impurities.
Risk evaluation
Assuming that no delamination is present on the package and given the low migration
capability of Pb particles, the risk of having emissive material on the silicon surface is very
low.
Item Assumption
We recommend our customers to avoid active soldering flux and to verify the integrity of
packages after board mounting in order to eliminate the possibilit y of package delamination
after device mounting on board, therefore eliminating the possibility of silicon contamination
by soldering material.
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Doc ID 024163 Rev 2