scope:

This guideline document establishes an Acoustic Emission (AE) method to enhance evaluation of the performance and reliability of surface mount attachments of electronic assemblies during mechanical loading. Mechanical loading may include stressors such as four-point bend test, spherical bend test, back-end manufacturing and test steps post surface mount attachment and drop/shock test. The current focus for this measurement method is to identify the printed board pad cratering mechanism and printed board material performance. This approach may eventually be extended to examine other failure modes depending on the guideline's evolution and adoption, as this method remains in development.

Purpose

The purpose of this document includes:

• Detection of crack/mechanical damage initiation: initial damage from strain may precede electrical detection of failures such as pad cratering damage during a mechanical stress test.

• Identification of the failure initiation location and propagation through detection of AE signals generated due to stress-induced physical damage.

• Estimation of the strain at which the mechanical failure event is observed acoustically, which can be used as a design guideline.

• Provision of standardized test guidelines and reporting procedures.