Standards Development

Scope

This part of IEC 61191 describes occurrence, detection and measurement of voids in surface -mount and through-hole solder joints of circuit board assemblies and establishes voiding requirements for automotive electronics. This document focuses exclusively o n voids in solder joints connecting packaged electronic or electromechanical components with circuit boards (CBs). The scope does not include voids in other solder joints (e.g. in a joint between a silicon die and a substrate within an electronic component, etc.).

Purpose

The necessity for the evaluation of voids in soldered joints increases in the industry because voids can affect the reliability of solder joints as the devices get smaller and power density increases. In parallel an increasing number of interconnections re quires an increase of reliability per solder joint as well.

This subject has been discussed in some countries and industry organizations, and specific proposals have been made for classification or evaluation of voids to develop process guidelines. The same subject is also studied in academia to find correlation be tween voids and reliability of a joint. Appreciable findings are now available from the reliability study including relation between shapes of voids and degradation of life due to voids in a joint in thermal cycle stress. Based on the information available, evaluation criteria of voids in solder joints have been developed and suitable measurement methods evaluated.

This document applies to electronic and electromechanical circuit board assemblies and describes current best-practices for dealing with voiding in solder joints of surface -mount and through-hole components soldered onto circuit boards independent of technical application.