Embedded Continuity Test Circuit for Bond Pad Integrity
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Solution Overview
Problem
Integrated circuits used in safety-critical applications require efficient continuity testing, but existing methods often rely on expensive test equipment and lengthy test times, especially for monitoring electrode and lead failures in implantable systems.
Innovation Solution
An embedded continuity test circuit within the integrated circuit generates a test oscillator signal based on capacitance at bond pads, using a dummy bond pad to create a fault reference frequency, allowing for field testing without expensive testers by comparing the test oscillator signal frequency with the fault reference signal frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional factory testing methods are used for continuity testing, then measurement precision can be achieved, but test time is extended and expensive test equipment is required
Solution Approach 1:
The integrated circuit performs continuity testing of its own bond pads using an embedded oscillator circuit and capacitance measurement logic, eliminating the need for external expensive test equipment. The circuit measures capacitance at each bond pad and compares it against threshold values to detect open or short conditions internally, thereby reducing external testing requirements and associated time losses.
2Reliability
If redundant circuitry is implemented for safety critical applications, then reliability is improved, but device complexity increases
Solution Approach 1:
The continuity testing functionality is merged with the normal operational circuitry of the integrated circuit. The oscillator circuit shares capacitive elements with the bond pad structures, and the capacitance measurement logic is integrated within the existing circuit framework. This combination allows the circuit to perform self-diagnosis without adding separate dedicated testing components, thereby maintaining reliability while controlling complexity.
3Manufacturing precision
If rigorous factory testing is performed on all bond pads, then manufacturing precision is ensured, but productivity is reduced due to extended test time
Solution Approach 1:
The capacitance measurement logic compares measured capacitance values against predefined threshold ranges to determine bond pad status. This partial action approach tests only the essential capacitance parameter rather than performing exhaustive electrical characterization, ensuring sufficient manufacturing precision while significantly reducing test time and improving production throughput.
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
This solution enables efficient continuity testing of bond pads, reducing test time and eliminating the need for expensive equipment, while providing a fault indication when the test oscillator signal frequency matches the fault reference signal frequency, thus ensuring the integrity of bond connections.
Implementation Method 1
an oscillator circuit (202) coupled at the first bond pad, the oscillator circuit configured to generate an oscillator signal having a first frequency based on a capacitance coupled at the first bond pad
Data Source
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AI summary
An embedded continuity test circuit is provided. An integrated circuit includes a bond pad and an oscillator circuit. The oscillator circuit is configured to generate an oscillator signal having a first frequency when the bond pad is coupled to a bond region of a package and a second frequency when the bond pad is not coupled to the bond region of the package.