Single Cycle ATPG Patterns for Multicycle Cell-Aware Defect Detection
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Solution Overview
Problem
Current testing methods for integrated circuit (IC) chips are inadequate in detecting multicycle cell-aware defects, as they primarily focus on faults between cell instances or outside cells, neglecting defects within cells, leading to incomplete defect detection.
Innovation Solution
The development of an IC test engine that generates single cycle test patterns capable of detecting static single cycle faults and simulates these patterns to detect multicycle faults, utilizing fault rules files associated with each cell type to enable detection of multicycle defects through sim-shifting, allowing single cycle test patterns to mimic multicycle test patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional testing methods are used that focus on faults between cell instances or outside cells, then the testing process is simpler and faster, but the detection of cell-aware defects is incomplete
Solution Approach 1:
The patent segments the testing approach into two phases: a first phase using traditional boundary model test patterns to detect faults between cells, and a second phase using cell-aware test patterns to detect defects within cells. This segmentation allows the system to maintain simplicity for common faults while adding complexity only where needed for comprehensive cell-aware defect detection.
Solution Approach 2:
The patent performs preliminary fault simulation during the test pattern generation phase to identify which cell-aware defects can be detected by single-cycle patterns and which require multi-cycle patterns. This preliminary analysis allows the system to prepare appropriate test strategies in advance without complicating the actual testing process.
2Measurement precision
If more test patterns are generated to detect all types of faults including multicycle cell-aware defects, then the detection accuracy improves, but the test application time increases
Solution Approach 1:
The patent creates test patterns that serve multiple functions: single-cycle test patterns are designed to detect both boundary model faults and cell-aware defects that can be detected within one cycle. Multi-cycle test patterns are generated only for defects that require multiple cycles, making each test pattern as efficient as possible while maintaining comprehensive coverage.
Solution Approach 2:
The patent changes the test pattern parameters (cycle length, pattern structure) based on the specific defect being detected. By adjusting these parameters dynamically based on fault type and detectability analysis, the system achieves high detection accuracy without uniformly applying complex multi-cycle patterns to all faults, thus reducing overall test time.
3Productivity
If single cycle test patterns are used, then the test application time is reduced, but the ability to detect multicycle defects is limited
Solution Approach 1:
The patent makes the test pattern selection dynamic by analyzing each defect's detectability characteristics. The system determines whether a single-cycle or multi-cycle pattern is needed based on the specific defect type and its propagation requirements, allowing the testing system to adapt its complexity to the actual testing needs rather than using a fixed approach.
Data Source
AI summary
An integrated circuit (IC) test engine can generate a plurality of single cycle test patterns that target a plurality of static single cycle defects of a fabricated IC chip based on an IC design. The IC test engine can also fault simulate the plurality of single cycle test patterns against a plurality of multicycle defects in the IC design, wherein a given single cycle test pattern of the plurality of single cycle test patterns is sim-shifted to enable detection of a given multicycle fault and/or defect of the plurality of multicycle faults and/or defects.