Sealing Ring Conductive Wall Layout for IC Crack Detection
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Solution Overview
Problem
Existing methods for detecting structural defects in integrated circuits, such as cracks and delamination, are inadequate in identifying certain configurations and locations, particularly affecting the sealing ring and BEOL part during wafer sawing.
Innovation Solution
An integrated circuit design incorporating an annular wall with alternating conductive stacks having trapezoidal longitudinal sections and staircase portions, connected to semiconductor zones, allows for improved detection of defects by enhancing the detectable locations of cracks and delamination through electrical conductivity analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection structures are used, then the device complexity is low, but the measurement precision is insufficient to detect certain crack configurations and delamination locations
Solution Approach 1:
The annular wall is divided into multiple conductive stacks arranged in alternating patterns, with each stack containing multiple conductive tracks at different levels. This segmentation allows detection of defects at various locations and orientations within the sealing ring structure.
Solution Approach 2:
The conductive stacks extend through multiple vertical levels of the integrated circuit, creating a three-dimensional detection network. This vertical dimension enables detection of delamination and cracks at different depths within the BEOL structure, not just at the surface level.
2Measurement precision
If the annular wall with multiple conductive stacks is implemented, then the detection capability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The alternating conductive stacks serve multiple functions: they form continuous conductive paths for defect detection, provide structural reinforcement to the annular wall, and create redundant detection pathways. This multi-functionality reduces the impact of minor manufacturing variations on overall detection capability.
Solution Approach 2:
The conductive tracks are designed with varying cross-sectional areas and spacing between stacks, creating parameter variations that enhance sensitivity to different types of defects while maintaining manufacturing feasibility through standard fabrication processes.
3Reliability
If existing detection methods are used, then the ease of manufacture is high, but the reliability of defect detection is insufficient
Solution Approach 1:
The defect detection function is merged with the existing sealing ring structure by integrating conductive stacks into the annular wall. This combination eliminates the need for separate detection structures, maintaining manufacturing simplicity while achieving reliable defect detection through the conductive path interruptions caused by cracks or delamination.
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
The proposed structure significantly improves the detection of structural defects by increasing the number of detectable locations, enabling effective identification of cracks and delamination, thereby enhancing the reliability of integrated circuits.
Implementation Method 1
adapted to be mutually electrically connected... All the first and second electrically conductive tracks forming together at least one electrically conductive path... detection circuit adapted to be connected to said semiconductor zones and configured to detect at least one type of structural defect... by detecting at least one electrical interruption of at least one electrically conductive path
Data Source
AI summary
The integrated circuit is equipped with an annular wall including, in a first part, an alternation of conductive stacks containing metal tracks distributed over several metal levels and having an alternately reversed trapezoidal longitudinal section, all these tracks forming together at least one electrically conductive path having at least one staircase portion in a second part of the wall. Defect-detection circuit are located in the integrated circuit and connected to semiconductor zones buried in the substrate under the second part of the wall and connected to the two ends of the at least one electrically conductive path.