Critical area based test pattern optimization for high-quality test
Measure pattern value based on the likelihood of the physical defects occurring
DFT engineers face challenges in setting target metrics for ATPG and choosing the best set of patterns for achieving high-quality test. Traditional coverage targets based on the number of faults detected don’t consider the likelihood of one fault occurring compared to another. Tessent developed total critical area ATPG technology to enable the sorting and ordering of patterns based on their likelihood to detect defects. Users can create a pattern set for multiple fault models in one run, reducing the overall pattern size significantly.
Total critical area (TCA) is the area in a design layout that determines the likelihood that a specific physical defect can cause a failure in the design TCA coverage is a significantly better measure for the quality of the applied test patterns than counting just the number of faults or defects. TCA-weighted ATPG represents a major step forward in ATPG for high-quality test for ICs that require very low defectivity, including automotive ICs that need to meet the ISO 26262 functional safety and quality standard.
Key features of TCA-weighted ATPG include:
• Selecting the most effective patterns
• Choosing targets for pattern types and coverage
• Determining the effectiveness of new pattern types
• Grading pattern value by likelihood to detect defects
• Automatically sorting and selecting patterns
• Creating a smaller pattern set by targeting multiple fault models in our ATPG run