Integrated Circuit Timing-Margin Sensing for Rare Failure Detection
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Solution Overview
Problem
Integrated circuits (ICs) face challenges in predicting and mitigating failures due to aging mechanisms such as hot-carrier injection, bias temperature instability, oxide breakdown, electromigration, stress migration, and random manufacturing defects, which can lead to timing violations and catastrophic failures, making it difficult to ensure reliable operation over their intended lifetime.
Innovation Solution
A sensor system is employed to measure logic circuitry in ICs by splitting signals into two test paths, applying varying delays based on predetermined timing margins, and comparing these paths to determine a fingerprint or signature of delays, enabling prediction of future failures and allowing for proactive measures to extend the IC's operational lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safety factor is used to account for manufacturing differences and aging, then the IC can operate reliably during its intended lifetime, but the timing margin decreases making the circuit more susceptible to timing violations
Solution Approach 1:
The patent applies preliminary action by measuring the timing margin of individual ICs during manufacturing before they are deployed. This allows the system to proactively identify ICs with insufficient timing margins and adjust their operational parameters or replace them before failures occur, rather than waiting for timing violations to happen during operation.
Solution Approach 2:
The patent utilizes parameter changes by adjusting operational parameters such as voltage and frequency based on the measured timing margin of each IC. ICs with smaller timing margins can be operated at lower frequencies or with adjusted voltage levels to ensure reliable operation, while ICs with larger margins can operate at higher performance levels.
2Measurement precision
If traditional aging mechanisms are monitored, then gradual performance degradation can be detected, but rare catastrophic failures from random defects cannot be predicted
Solution Approach 1:
The patent applies partial or excessive action by measuring the timing margin with high precision during manufacturing, which exceeds the normal operational monitoring requirements. This excessive measurement precision during the manufacturing phase allows detection of subtle variations in timing characteristics that may indicate susceptibility to rare catastrophic failures, enabling better reliability prediction than continuous operational monitoring alone.
3Reliability
If individual IC timing margins are measured during manufacturing, then rare defects can be detected, but the measurement and classification process becomes more complex
Solution Approach 1:
The patent uses copying by creating a digital representation or fingerprint of each IC's timing margin characteristics during manufacturing. This digital copy is stored and used for later classification and operational decision-making, avoiding the need for complex physical measurements during operation while maintaining the ability to detect rare defects.
4Productivity
If ICs are operated at higher frequencies to improve performance, then productivity increases, but the risk of timing violations due to aging and manufacturing variations increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the operational frequency and voltage based on each IC's measured timing margin. ICs with larger timing margins can operate at higher frequencies for improved productivity, while ICs with smaller margins are operated at lower frequencies to maintain reliability, optimizing the trade-off between productivity and reliability for each individual device.
Data Source
AI summary
A specific logic circuitry of a semiconductor Integrated Circuit (IC) is measured by a sensor. The sensor includes: a signal splitter that splits a signal from the specific logic circuitry into two test paths; a delay element that receives and applies a delay to a first test path, the delay based on a predetermined timing margin that is selected from a group of discrete timing margin values comprising a shortest timing margin value and at least one longer timing margin value; a comparison circuit that compares the delayed first test path and a second test path and provides a measurement output according to the comparison for an instance of measuring; and a controller that sets the predetermined timing margin such that, over the instances of measuring, a frequency of selection of the shortest timing margin value is higher than a frequency of selection of each longer timing margin value.