Semiconductor Wafer Test Key Structure Using Seal Ring Routing
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Solution Overview
Problem
The increasing complexity of semiconductor chips requires broader scribe line regions for more test pads and elements, which reduces the available area on the wafer and complicates the dicing process.
Innovation Solution
The semiconductor wafer design incorporates a seal ring region between the scribe line and chip regions, where test key structures are placed, reducing the scribe line width by forming test pads with openings that mitigate stress and allow for faster dicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If more test pads and test elements are added to the scribe line region to accommodate complicated circuits, then the testing capability is improved, but the scribe line width increases and the available wafer area decreases
Solution Approach 1:
The patent utilizes the seal ring region, which is a spatial dimension between the scribe line and chip region, to route conductive lines. This dimensional utilization allows test signals to reach test elements without requiring wider scribe lines, thereby maintaining wafer area while improving testing capability.
Solution Approach 2:
The patent introduces conductive lines as intermediaries that extend from the scribe line region through the seal ring region to connect with test elements. This intermediary structure enables electrical connection without directly expanding the scribe line width, resolving the contradiction between testing capability and wafer area.
2Adaptability or versatility
If the scribe line width is increased to accommodate more test structures, then the testing functionality is improved, but the dicing process becomes more complex and slower
Solution Approach 1:
The patent segments the test key structure into two parts: test pads and test elements located in the scribe line region, and conductive lines routed through the seal ring region. This segmentation allows the scribe line to remain narrow for fast dicing while still providing complete testing functionality through the distributed structure.
3Reliability
If test pads are made larger to improve electrical connection reliability, then the connection reliability is improved, but the scribe line width increases reducing wafer area
Solution Approach 1:
The patent extends the electrical connection path into the seal ring region using conductive lines, allowing test pads to remain compact in the scribe line region while achieving reliable electrical connection through the extended path in the adjacent seal ring region.
Data Source
AI summary
A semiconductor wafer with a test key structure is provided. The semiconductor wafer includes a semiconductor substrate including a scribe line region, a chip region, and a seal ring region between the scribe line region and the chip region. A test pad structure and a test element are disposed over the semiconductor substrate corresponding to the scribe line region. A conductive line is disposed over the semiconductor substrate corresponding to the seal ring region, and has two ends extending to the scribe line region and electrically connected between the test pad structure and the test element.