Screening Printed Wiring Boards Using Electric Field Dielectric Life Curves

Solution Overview

Problem

Printed wiring boards (PWBs) fail due to electric fields caused by electrical signals passing through laminated copper traces, and conventional burn-in techniques are inadequate in detecting premature failures effectively.

Innovation Solution

A method and system that characterize the effects of electric fields on PWBs by generating test data to determine a dielectric life curve, defining a screening time and voltage to identify and prevent premature failures in subsequent PWBs, using a test development unit to generate electric fields, detect failures, and develop screening parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional burn-in techniques are used to stress circuit components, then components that would fail prematurely can be detected, but the techniques are inadequate for detecting premature failures in PWBs caused by electric fields

Engineering Contradiction:

Improvedetection effectivenessVSAvoidapplicability to PWB electric field failures

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the test parameters from conventional thermal and voltage stress to electric field stress parameters. By applying high voltage AC signals at specific frequencies (e.g., 60 Hz, 400 Hz, or operating frequencies) to the PWB traces, the method creates electric field conditions that simulate real-world operational stress on the dielectric material between copper traces, enabling detection of premature failures specific to PWBs

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary characterization tests on a first set of PWBs to generate dielectric life curve data before production screening. By conducting these tests upfront to establish the relationship between electric field stress, time, and failure rates, the method enables optimized screening parameters to be determined in advance for efficient production testing of subsequent PWBs

Inventive Principle:

Principle #10Preliminary action

2Reliability

If high stress levels are applied during burn-in testing, then premature failures can be detected, but the screening process becomes time-consuming and inefficient

Engineering Contradiction:

Improvefailure detection capabilityVSAvoidscreening efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent performs preliminary characterization tests on a first set of PWBs to generate dielectric life curve data before production screening. By conducting these tests upfront to establish the relationship between electric field stress, time, and failure rates, the method enables optimized screening parameters to be determined in advance for efficient production testing of subsequent PWBs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback from dielectric life curve characterization data to optimize screening parameters. By analyzing failure data from initial tests and adjusting screening voltage and time parameters based on the established life curves, the method achieves efficient screening that detects premature failures without requiring excessive test duration on all units

Inventive Principle:

Principle #23Feedback

3Measurement precision

If dielectric life curve characterization is performed on a first set of PWBs, then optimal screening parameters can be determined, but additional testing time and resources are required

Engineering Contradiction:

Improvescreening parameter accuracyVSAvoidcharacterization testing time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary characterization tests on a first set of PWBs to generate dielectric life curve data before production screening. By conducting these tests upfront to establish the relationship between electric field stress, time, and failure rates, the method enables optimized screening parameters to be determined in advance for efficient production testing of subsequent PWBs

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses a small sample set of PWBs for characterization testing to create dielectric life curves that represent the broader population. By deriving screening parameters from this representative sample, the method avoids the need to perform exhaustive testing on every individual PWB while still achieving accurate and reliable screening parameters for production use

Inventive Principle:

Principle #26Copying

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables the prediction of life expectancy and effective screening of PWBs to prevent premature failures by defining optimal screening times and voltages based on dielectric life curves, thereby improving the reliability of PWBs.

Implementation Method 1

characterizing the effects of an electric field on a first set of printed wiring boards (PWBs) by testing the first set of PWBs

Methodology Applied

Scientific EffectElectric field: Electric Field

Data Source

PatentUS9551744B2Detecting early failures in printed wiring boards

Publication Date: 2017.01.24 HAMILTON SUNDSTRAND CORP

AI summary

A method includes characterizing the effects of an electric field on a first set of printed wiring boards (PWBs) by testing the first set of PWBs to generate test data, using the test data to determine a dielectric life curve of the first set of PWBs, and based on the dielectric life curve, defining a screening time and a screening voltage to screen for premature failures in a second set of PWBs due to electric fields.