Electrical Plus Functional Testing in Designing Electronics for Harsh Conditions

Mike Bixenman, DBA, Bobby Glidwell
Magnalytix, LLC
TN, USA

Terry Munson, Paco Solis, Jim Gryga, & Steve Middleton
Foresite, Inc.
IN, USA

Electronic device reliability is more challenging due to various factors related to increased functionality, component miniaturization and design, materials, assembly process, and the demands of the user environment. Factors such as ambient humidity and temperature conditions, day/night temperature variations, cleanliness of the electronic circuitry, PCBA design, and surface characteristics all influence device reliability.

Advanced technologies across many fields rely on electronic and software functions that perform on demand. Most reported failures arise from process-related contamination reacting with the operational environment, creating latent failures from the remaining trapped residues on the PCBA surface after the soldering operations.

This paper proposes a new test method and test vehicle to characterize soldering materials, assembly process steps, and conformal coating to determine the reliability of a device.

The test assembly and instrumentation are tools designed to understand the material effects under SIR conditions of different component structures, along with the interactive effects of the collective of residues from the multiple soldering/cleaning or soldering and No-Clean operation on the functional circuits and their interactivity in typical operation conditions. The goal is to show the effect of why a short in one area will crash a separate part of the circuit with just a few ohms of leakage or sensitive circuits that may or may not recover. SIR misses the effect of circuit sensitivity on functional performance. The test vehicle design is the first step to creating this understanding.