Considerations on SPC56x70xx package and soldering procedures

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Considerations on SPC56x70xx package and

soldering procedures

2.1

Introduction

SPC56x70xx package is composed by Ultra Low Alpha mold compound. Measurements

This value has been used in the SPC56x70xx quantitative safety analyses (see

SPC56x70xx 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

Risk analysis

2.2.1

Risk item

Single Event Upset randomly induced by alpha particle emission from Package material.

2.2.2

Cause

A possible cause of silicon contamination is the presence of potentially alpha-emissive

soldering material, specifically induced by Pb impurities.

2.2.3

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.

2.2.4

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 possibility of package delamination

after device mounting on board, therefore eliminating the possibility of silicon contamination

by soldering material.