Via Chain Crack Detection in IC Die Seals
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Solution Overview
Problem
Integrated circuit (IC) devices with die seals are prone to mechanical cracks that can propagate through the seal, leading to device failures, which are difficult to detect.
Innovation Solution
A via chain structure is implemented around the die seal, comprising conductive portions and pads that allow for electrical testing by detecting open or short circuits, indicating crack propagation through the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a die seal is used to protect the IC device from mechanical cracks, then the device reliability is improved, but mechanical cracks may still break through the die seal leading to device failures that are difficult to detect
Solution Approach 1:
A via chain structure is formed around the die seal before final device packaging, creating a detection mechanism in advance. The via chain includes multiple vias connected in series that can detect cracks before they cause device failure, allowing early identification and removal of defective devices from the batch.
Solution Approach 2:
The via chain acts as an intermediary detection layer between the die seal and the external environment. It provides a sensing mechanism that indirectly detects cracks in the die seal by monitoring changes in the via chain's electrical properties, making invisible cracks detectable without directly observing the seal itself.
2Strength
If the die seal is made stronger to prevent crack propagation, then the protective function is improved, but the complexity of detecting cracks through the seal increases
Solution Approach 1:
The detection function is segmented from the die seal structure itself. Instead of trying to detect cracks in the continuous die seal, the via chain divides the detection into discrete segments (individual vias) that can be electrically tested. This segmentation allows the strong die seal to maintain its protective function while the separate via chain provides detection capability.
3Difficulty of detecting and measuring
If electrical testing methods are implemented to detect cracks, then the detection capability is improved, but the device complexity increases
Solution Approach 1:
The via chain serves multiple functions: it provides electrical connectivity for signal routing and simultaneously acts as a crack detection sensor. This multi-functionality reduces overall device complexity by combining detection capabilities with existing structural elements rather than adding separate dedicated detection components.
Solution Approach 2:
The via chain structure tests itself for cracks through its own electrical properties. The via chain's continuity and resistance characteristics serve as the detection mechanism, eliminating the need for external complex detection systems. The structure is self-diagnosing through simple electrical measurements during or after packaging.
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 reliable detection of cracks in IC devices, preventing failures by identifying breakages in the via chain, which signifies crack propagation through the die seal, thereby ensuring the integrity of the integrated circuit region.
Implementation Method 1
A via chain is arranged around an inner circumference of the die seal between the die seal and the integrated circuit region. The via chain may include a plurality of contacts extending through portions of the die.
Data Source
AI summary
Apparatuses and methods can include a die seal between an integrated circuit region of a die and a periphery of the die. A via chain(s) may be arranged around an inner circumference of the die seal between the die seal and the integrated circuit region and/or around an outer circumference of the die seal between the die seal and the periphery of the die. The via chain may include a plurality of contacts comprised of conductive material and extending through portions of the die. Circuitry may be coupled to an end of the via chain to detect an electrical signal. Additional apparatuses and methods are described.