Crack Stop Pillars With Overlapping Vias
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Solution Overview
Problem
Integrated circuits (ICs) face delamination issues during processing and wear, where cracks propagate through conventional crack stop structures due to uniform via depths, potentially reaching active devices and causing failures.
Innovation Solution
The introduction of crack stop pillars with vias of different depths in each via layer, including overlapping and flush vias, to impede or prevent delamination crack propagation by creating non-planar interfaces that disrupt crack progression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional crack stop structures with uniform via depths are used, then the structure is simple to manufacture, but cracks can propagate through the uniform interfaces and reach active devices
Solution Approach 1:
The patent applies local quality by varying the via depths within the crack stop structure. Different via layers have different via depths, creating non-uniform interfaces that locally disrupt crack propagation paths. This is achieved by selectively forming vias to different depths in different regions of the crack stop structure, making each local interface unique and resistant to crack propagation.
Solution Approach 2:
The patent introduces depth variation as an additional dimension to the crack stop structure. Instead of uniform via depths, the structure incorporates multiple depth levels (first depth, second depth, third depth) across different via layers. This dimensional variation creates a three-dimensional non-planar interface that effectively blocks crack propagation while maintaining manufacturing feasibility.
2Reliability
If crack stop pillars with varying via depths are implemented, then crack propagation is disrupted, but the manufacturing process becomes more complex
Solution Approach 1:
The patent segments the crack stop structure into multiple via layers, each with distinct via depth characteristics. The crack stop structure is divided into first, second, and third via layers, where each layer contains vias with specific depth variations. This segmentation allows for controlled complexity in each layer while maintaining overall manufacturability through systematic fabrication processes.
Solution Approach 2:
The patent changes the depth parameter of vias across different layers to achieve crack propagation resistance. By systematically varying via depths (first depth, second depth, third depth) in different via layers, the structure creates non-uniform interfaces that disrupt cracks. This parameter variation is implemented through controlled fabrication processes that can handle multiple depth levels.
Data Source
AI summary
A crack stop structure for an integrated circuit (IC) structure is disclosed. The structure can include: a first crack stop pillar laterally separated from a second crack stop pillar within an insulator region of the IC structure. The first crack stop pillar can include an overlapping via in contact with a top surface and at least one side surface of a first conductive element therebelow. The overlapping via of the first crack stop pillar may be in a given layer of the IC structure, and the second crack stop pillar may include a via in the given layer, the via extending to a different depth than the overlapping via. The via of the second crack stop pillar may be an overlapping via in contact with a top surface and at least one side surface of a second conductive element therebelow.