IC Package Test Pattern Comparison Circuit
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Solution Overview
Problem
Current automated functional testing of integrated circuits and multi-chip packages faces challenges in efficiently comparing test output patterns with expected patterns, particularly in determining pass or fail results due to the complexity of scan chains and the need for precise mask patterns.
Innovation Solution
An integrated circuit (IC) package with a set of interconnected circuit elements and a comparison circuit that receives test patterns and signature patterns from external test apparatus, generates test output patterns, and compares them to determine test results, with the option to apply mask patterns for specific pass or do-not-care results, facilitating efficient die-level and package-level testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scan-based testing is used to test integrated circuits, then functional testing capability is improved, but test complexity and difficulty of comparing test outputs increases
Solution Approach 1:
The patent introduces an intermediary device (tester or test system) that mediates between the scan chains and the comparison operation. This intermediary captures the scanout data, applies mask patterns, and performs the comparison with expected results, thereby simplifying the overall test complexity while maintaining functional testing capability.
Solution Approach 2:
The patent extracts the comparison function from the complex scan chain testing process by separating it into a distinct operation. The test system extracts only the necessary test results from the scan chains and compares them against expected patterns, avoiding the need to analyze the entire complex scan chain output in detail.
2Measurement precision
If precise mask patterns are applied to determine pass or fail results, then test accuracy is improved, but test processing time increases
Solution Approach 1:
The patent applies mask patterns selectively to only those portions of the test output that are critical for determining pass or fail results. By masking out non-critical portions, the system achieves accurate testing of essential functions while reducing the overall processing time compared to analyzing the complete test output in detail.
Solution Approach 2:
The mask pattern technique applies different quality levels to different portions of the test data. Critical test results are analyzed with high precision while non-critical results are masked or given lower priority, optimizing the balance between test accuracy and processing time through localized quality differentiation.
Data Source
AI summary
Aspects of the disclosure include an integrated circuit (IC) that includes a first input port configured to receive a test pattern, a second input port configured to receive a signature pattern, a set of interconnected circuit elements, and a comparison circuit. The signature pattern is indicative of an expected test output pattern in response to the test pattern. The set of interconnected circuit elements is configured to generate a test output pattern in response to the test pattern being passed through the set of interconnected circuit elements. The comparison circuit is configured to compare the test output pattern to the signature pattern, generate a test result based on a comparison result of the test output pattern to the signature pattern, and output the test result to the test apparatus.