Inter-cell bridge defect diagnosis via simulation segmentation
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Solution Overview
Problem
Conventional diagnosis techniques often miss inter-cell bridge defects or generate excessive cell suspects, making it inefficient to identify the root cause of faulty integrated circuit devices.
Innovation Solution
A method involving processor-executed simulations to determine initial and final defect suspects by analyzing test responses, layout information, and electrical data, specifically identifying inter-cell bridge suspects through failing and passing test pattern simulations, and using path-tracing or fault dictionary approaches to pinpoint defect sites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional scan diagnosis techniques are used to identify faulty locations, then diagnosis coverage is improved, but inter-cell bridge defects are missed and excessive cell suspects are generated
Solution Approach 1:
The diagnosis process is segmented into two distinct phases: (1) conventional scan diagnosis to identify cell suspects, and (2) inter-cell bridge defect diagnosis to specifically detect bridge defects between cells. This segmentation allows each phase to focus on its strength without compromising the other, resolving the contradiction between detection accuracy and completeness
Solution Approach 2:
Layout information is introduced as an intermediary element that connects conventional scan diagnosis results with inter-cell bridge defect detection. By incorporating spatial relationships between cells, the system can identify bridge defects that conventional electrical information alone cannot detect, thereby improving defect detection completeness
2Measurement precision
If conventional diagnosis techniques generate cell suspects based on test responses, then diagnosis resolution is improved, but the number of suspects becomes excessive for efficient analysis
Solution Approach 1:
The suspect identification process is segmented into conventional cell suspects and inter-cell bridge suspects, with each category processed through appropriate analysis methods. This segmentation prevents the mixing of different defect types, allowing PFA engineers to focus on fewer, more relevant suspects and improving analysis efficiency
Solution Approach 2:
Different analysis methods are applied to different suspect categories: conventional electrical analysis for cell internal defects and layout-based spatial analysis for inter-cell bridge defects. This localized approach ensures each suspect type is evaluated with the most appropriate method, improving both resolution and efficiency
3Measurement precision
If failing test pattern simulations are performed to identify defect suspects, then defect location accuracy is improved, but analysis time increases
Solution Approach 1:
Conventional scan diagnosis is performed first to identify potential cell suspects before conducting inter-cell bridge defect analysis. This preliminary action narrows down the search space, allowing subsequent bridge defect analysis to focus only on relevant cell pairs, thereby maintaining accuracy while reducing overall analysis time
Data Source
AI summary
Failing test pattern simulations are performed to determine initial defect suspects based on injecting faults to defect candidate sites which are derived based on test responses. Initial inter-cell bridge suspects are then determined from cells in the initial defect suspects based on layout information and electrical information of the circuit. Passing test pattern simulations are performed to determine inter-cell bridge suspects from the initial inter-cell bridge suspects.