Perimeter Line Crack Detection in IC Inactive Regions
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Solution Overview
Problem
Integrated circuits (ICs) face challenges in detecting and monitoring cracks that form during the dicing process, which can propagate due to environmental fluctuations, potentially leading to failure, as existing crack detection systems only alert after the crack has reached the active region, which is too late for prevention.
Innovation Solution
A system comprising electrically conductive perimeter lines (PLINEs) in the inactive region of the IC, connected to a sensing circuit that monitors changes in electrical characteristics, providing early warnings before cracks propagate into the active region, using straddling or tunneling connections to couple PLINEs to the detection circuit without compromising the guard ring or crackstops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If crack detecting structures are placed in the active region of the IC inside the crackstop, then the presence of a crack can be detected, but the detection occurs after the crack has already reached the active region which is too late for prevention
Solution Approach 1:
The patent places perimeter lines (PLINEs) in the inactive region surrounding the active region, before the crackstop structure. This preliminary positioning allows the detection system to identify cracks early in the inactive region before they can propagate into the active region, enabling preventive action rather than post-detection
2Loss of time
If PLINEs are placed in the inactive region to enable early detection, then early warning can be provided, but additional structures and connections are required which increase device complexity
Solution Approach 1:
The PLINEs serve multiple functions: they act as crack detection sensors, provide electrical connection pathways, and can be integrated with existing IC structures. The same PLINE structure that detects cracks also serves as part of the interconnect architecture, reducing the need for separate dedicated sensor structures
Solution Approach 2:
The patent introduces PLINEs as intermediary structures between the inactive region and the active region. These PLINEs are coupled to the active region through straddling or tunneling connections, serving as mediators that enable early crack detection while maintaining electrical isolation and structural integrity
3Reliability
If straddling or tunneling connections are used to couple PLINEs to the sensing circuit, then electrical coupling is achieved without compromising the guard ring or crackstops, but the connecting structure becomes more complex
Solution Approach 1:
The connection structure is divided into multiple segments: PLINEs in the inactive region, straddling/tunneling connection elements that bridge across the active region boundary, and sensing circuit connections. This segmentation allows each component to be optimized independently while maintaining overall system integrity and avoiding compromise of the guard ring or crackstop structures
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 early detection and monitoring of cracks in the inactive region, providing timely alerts and allowing for proactive replacement of ICs to prevent failure, with the system calibrated to estimate the time to failure based on crack growth rates.
Implementation Method 1
a circuit for sensing a change in an electrical characteristic of the at least one PLINE, the change in the electrical characteristic indicating a presence of a crack in the inactive region of the IC
Data Source
AI summary
Embodiments of the disclosure provide a system for detecting and monitoring a crack in an integrated circuit (IC), including: at least one electrically conductive perimeter line (PLINE) extending about, and electrically isolated from, a protective structure formed in an inactive region of the IC, wherein an active region of the IC is enclosed within the protective structure; a circuit for sensing a change in an electrical characteristic of the at least one PLINE, the change in the electrical characteristic indicating a presence of a crack in the inactive region of the IC; and a connecting structure for electrically coupling each PLINE to the sensing circuit.