Segmented Test Line Structure for Semiconductor Defect Detection
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Solution Overview
Problem
The yield in integrated circuit manufacturing is affected by various failures in semiconductor wafers, making it challenging to identify and prioritize the root cause of defects during physical failure analysis.
Innovation Solution
The implementation of test line structures with diagnosis units and micro pad units, which form a test chain to evaluate the interconnect structures using multiple metal layers and via layers, allowing for the detection of defects and optimization of processing parameters through wafer acceptance tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional test methods are used without structured test line structures, then the manufacturing process is simpler, but the ability to identify and analyze defect root causes is insufficient
Solution Approach 1:
The test line structure is segmented into multiple diagnosis units, each containing specific interconnect structures with different routing patterns. This segmentation allows defects to be localized to specific units and routing patterns, improving measurement precision while maintaining manageable complexity through modular design.
Solution Approach 2:
Different diagnosis units are designed with different routing patterns (e.g., meander patterns, straight patterns, different via counts) to test specific interconnect characteristics locally. This local quality approach enables targeted defect detection for different interconnect structures without requiring a completely complex test structure.
2Loss of information
If multiple diagnosis units with different routing patterns are implemented, then the root cause analysis capability is improved, but the test line structure becomes more complex
Solution Approach 1:
The test line structure serves multiple functions: it tests interconnect resistance, via connectivity, routing pattern integrity, and provides failure location information. By combining these functions into a single integrated test structure with multiple diagnosis units, the system reduces information loss about failure causes while managing complexity through multi-functionality.
Solution Approach 2:
The test line structure extends into the scribe line area, utilizing the peripheral dimension of the wafer that is not occupied by active device areas. This dimensional approach allows complex test structures to be added without interfering with the main device layout, thereby reducing the perceived complexity in the device area.
3Area of stationary object
If test line structures are formed in the scribe line area, then the device area is preserved, but the scribe line space utilization becomes critical
Solution Approach 1:
The test line structures are extracted from the active device area and placed in the scribe line area. This extraction preserves the device area for productive use while dedicating the scribe line space to testing functions. The scribe line, which would otherwise be non-productive space, is now efficiently utilized for multiple test purposes.
Data Source
AI summary
Test line structures are provided. A test line structure includes a semiconductor substrate, a plurality of diagnosis units and a plurality of first micro pad units. The diagnosis units are formed over the semiconductor substrate. Each of the diagnosis units includes a first interconnect structure having a first routing pattern. The first interconnect structures of the diagnosis units are connected in series to form a first test chain through the first micro pad units, and each of the first micro pad units is configured to connect the first interconnect structures of two adjacent diagnosis units in the first test chain. The first routing patterns of the first interconnect structures in the diagnosis units are different.