Segmented Probe Pad Design for Saw Lane Defect Reduction
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Solution Overview
Problem
During the sawing process of semiconductor wafers containing integrated circuits, metal from metallized structures can cause short circuit defects and cracks in dielectric layers, leading to edge defects in the integrated circuits.
Innovation Solution
The implementation of a semiconductor wafer fabrication method that includes forming segmented probe pad structures in the saw lanes between integrated circuits, with each probe pad structure comprising unsegmented and segmented pads at different interconnect levels, where the pad segments have a maximum lateral dimension up to 75% of the probe pad width, and are electrically connected via vias, to minimize metal interconnect elements and reduce defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If metalized structures such as test components are placed in saw lanes, then electrical testing can be performed on integrated circuits, but metal from these structures causes short circuit defects at edges of the integrated circuits during sawing
Solution Approach 1:
The probe pad is divided into multiple pad segments separated by dielectric material, creating a segmented structure that reduces metal continuity and minimizes short circuit risks during sawing while preserving electrical testing functionality
Solution Approach 2:
Metal interconnect elements are removed or minimized in the saw lane region, extracting the harmful metal component while retaining the essential probe pad functionality through the segmented structure
2Reliability
If probe pads are placed in saw lanes for testing, then electrical connectivity is established, but cracks and chips in dielectric layers occur during sawing process
Solution Approach 1:
The continuous dielectric layer is segmented into multiple dielectric layers separated by metal interconnect elements, creating a stepped configuration that reduces stress concentration and prevents cracks during sawing while maintaining electrical connectivity through vias
3Reliability
If continuous metal interconnect elements are used in probe pads, then electrical connectivity is ensured, but metal causes short circuit defects and increased device complexity
Solution Approach 1:
The metal interconnect is segmented into multiple discrete elements separated by dielectric layers, reducing overall metal content and structural complexity while maintaining electrical connectivity through the segmented path with vias
Solution Approach 2:
Excessive metal interconnect elements are removed from the probe pad structure, extracting only the essential conductive paths needed for connectivity while eliminating redundant metal that would increase complexity and defect risk
Data Source
AI summary
An integrated circuit wafer and fabrication method includes a probe pad structure in saw lanes between integrated circuits. The probe pad structure includes a probe pad with a plurality of pad segments. The pad segments are elements of an interconnect level of the wafer.