Wafer Scribe-Line TEG Layout for Narrow Probe Pad Testing
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Solution Overview
Problem
The challenge of integrating test element groups (TEGs) in reduced scribe lines of semiconductor wafers is exacerbated by the inability to shrink the size of probe pads, which often overlap with chip areas as scribe lines narrow, impacting the efficiency of wafer production.
Innovation Solution
A test element group design with a first and third probe pad arrangement, featuring upper and lower row contacting regions, allowing for reduced scribe line width by maintaining the original metal routing while enabling electrical connections through vias to either the upper or lower row contacting regions, thereby reducing the overall width to 50-60 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the scribe line width is reduced to increase chip density, then the number of chips per wafer increases, but the test element group cannot be properly accommodated
Solution Approach 1:
The test element group is segmented into multiple probe pads (first probe pad, second probe pad, third probe pad) arranged in sequence, with contacting regions positioned between them. This segmentation allows the TEG to be distributed across the scribe line rather than requiring a single large continuous structure, enabling accommodation within reduced scribe line width while maintaining all necessary testing functions.
Solution Approach 2:
The patent utilizes the width dimension of the scribe line by positioning contacting regions at different locations (upper row and lower row) relative to the probe pads. This dimensional arrangement allows the TEG to utilize vertical spacing within the scribe line area, effectively reducing the horizontal width requirement and enabling proper accommodation in narrowed scribe lines.
2Reliability
If the probe pad size is maintained to ensure proper electrical connection, then the testing function is preserved, but the scribe line width cannot be reduced
Solution Approach 1:
The patent applies local quality by positioning contacting regions at specific locations between probe pads where electrical connections are most effectively established. The contacting regions are strategically placed to optimize electrical connectivity to the probe pads while minimizing the overall scribe line width, allowing reduced width without compromising connection reliability.
Solution Approach 2:
The contacting regions serve as intermediary structures between the probe pads and the test equipment. These intermediate contacting regions enable electrical connections to be established more efficiently, allowing the probe pads to be positioned closer together and reducing the overall scribe line width while maintaining reliable electrical connectivity.
3Adaptability or versatility
If additional photomasks are used to test both upper and lower chips, then testing flexibility is improved, but the manufacturing complexity increases
Solution Approach 1:
The test element group is designed with multi-functionality, where the same probe pad structure and contacting regions can serve both upper and lower chips through selective electrical connection. The contacting regions can be electrically connected to different probe pads depending on the testing requirement, allowing a single TEG design to perform multiple testing functions without requiring separate dedicated structures for each chip, thereby reducing photomask complexity.
Data Source
AI summary
Provided is a test element group located at a scribe line of a wafer, including a first probe pad, at least one second probe pad, at least one third probe pad, at least one upper row contacting region, and at least one lower row contacting region. When the at least one upper row contacting region is electrically connected to the first probe pad, the at least one second probe pad, and the at least one third probe pad, the at least one lower row contacting region is insulated from the first probe pad, the at least one second probe pad, and the at least one third probe pad, vice versa. Thus, the original metal routing of double row TEGs are kept, but the contact is landed to one row of TEG's probe pad.