IC Chip Reliability via Process Window Segmentation

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Solution Overview

Problem

Integrated circuit (IC) chip reliability is compromised due to various failure mechanisms such as time-dependent dielectric breakdown, hot carrier injection, and electromigration, which are not uniformly distributed across the manufacturing process distribution, leading to inconsistent performance and potential chip failure.

Innovation Solution

The method involves sorting IC chips into groups based on process windows within a distribution, setting group fail rates for multiple failure mechanisms, and determining overall fail rates to identify specific failure mechanisms for targeted improvements in manufacturing processes, ensuring reliability and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If manufacturing process improvements are implemented with the assumption of uniform impact across the full process distribution, then implementation complexity is reduced, but reliability improvement effectiveness deteriorates because failure mechanisms are not uniformly distributed across process windows

Engineering Contradiction:

Improveprocess improvement implementation complexityVSAvoidreliability improvement effectiveness

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the full process distribution into multiple process windows (e.g., fast, nominal, slow) and analyzes failure mechanisms separately for each window. This allows identification of which failure mechanisms dominate in each segment, enabling targeted process improvements that address the specific reliability needs of each process window rather than applying uniform improvements across all chips.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies local quality by tailoring process improvements to specific process windows based on their unique failure mechanism profiles. For example, if TDDB is the dominant failure mechanism in the fast process window while EM dominates in the slow window, different process parameter adjustments are applied to each window to optimize reliability for that specific segment.

Inventive Principle:

Principle #3Local quality

2Reliability

If all failure mechanisms are addressed uniformly across the full process distribution, then comprehensive reliability coverage is achieved, but resource allocation efficiency deteriorates due to lack of targeted intervention

Engineering Contradiction:

Improvecomprehensive reliability coverageVSAvoidresource allocation efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements partial action by focusing process improvements on the most critical failure mechanisms for each process window rather than attempting to address all failure mechanisms uniformly. By identifying the dominant failure mechanism in each process window (e.g., TDDB in fast window, EM in slow window), resources are concentrated on the most impactful interventions for each segment, achieving comprehensive coverage through targeted rather than exhaustive approaches.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent uses parameter changes to optimize process conditions for each process window based on its specific failure mechanism profile. By adjusting process parameters (such as temperature, time, material composition) differently for each window, the patent achieves effective reliability improvement with optimized resource allocation, addressing only the parameters that significantly impact the dominant failure mechanisms in each segment.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If process parameter variations are not accounted for when determining reliability, then reliability assessment simplicity is improved, but measurement precision deteriorates because reliability cannot be accurately determined across the full process distribution

Engineering Contradiction:

Improvereliability assessment simplicityVSAvoidreliability measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the process distribution into distinct process windows and determines reliability separately for each window based on its specific process parameter characteristics. This segmentation allows the use of simplified assessment methods within each window while maintaining high overall accuracy, as each window's reliability is calculated using parameters appropriate to that specific segment rather than attempting a single complex model for the entire distribution.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9639645B2Integrated circuit chip reliability using reliability-optimized failure mechanism targeting

Publication Date: 2017.05.02 MARVELL ASIA PTE LTD

AI summary

Disclosed are methods for improving integrated circuit (IC) chip reliability. IC chips are manufactured and sorted into groups corresponding to process windows within a process distribution for the design. Group fail rates are set for each group based on failure mechanism fail rates, which are set for multiple failure mechanisms. An overall fail rate is determined for the full process distribution based on the group fail rates. First contribution amounts of the groups to the overall fail rate and second contribution amounts of the failure mechanisms to the group fail rate of each group are determined. Based on an analysis of the contribution amounts, at least one specific failure mechanism is selected and targeted for improvement (i.e., changes directed to the specific failure mechanism(s) are proposed and implemented). Optionally, proposed change(s) are only implemented if they will be sufficient to meet a reliability requirement and/or will not be cost-prohibitive.