Optical Mixed Signal Tester for Anomaly Detection
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Solution Overview
Problem
Current methods for testing mixed-signal systems are costly and lack comprehensive, low-cost methodologies, relying on specification-based testing that is inefficient for high-volume production and assumes a predefined list of faults, which is not practical for analog and mixed-signal ICs.
Innovation Solution
An optical mixed signal tester system that scans mixed signal devices with an optical source while monitoring multiple parameters simultaneously, forming images and comparing them to reference images to detect anomalies, allowing for real-time identification of defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specification-based testing is used to ensure circuit parameters meet requirements, then testing thoroughness is improved, but testing cost increases significantly
Solution Approach 1:
The patent replaces traditional electrical specification-based testing with optical field-based imaging techniques. Instead of applying electrical stimuli and measuring electrical responses, the system uses optical fields to image the internal circuit structure and detect anomalies visually, thereby reducing testing cost while maintaining detection capability
Solution Approach 2:
The patent creates optical copies (images) of the circuit's internal structure and operational state. By capturing and analyzing optical images of the circuit under test, the system can detect anomalies without performing expensive electrical specification tests, thus reducing testing cost while maintaining thoroughness
2Device complexity
If fault-based testing with predefined fault lists is used, then test generation is simplified, but adaptability to realistic faults deteriorates
Solution Approach 1:
The patent performs preliminary optical imaging of the circuit to capture its baseline structure and operational characteristics before testing. This preliminary action creates a reference state that enables detection of various fault types without requiring predefined fault lists, thereby simplifying test generation while maintaining high adaptability
Solution Approach 2:
The patent implements a universal optical imaging system that can detect multiple types of faults (open circuits, short circuits, manufacturing defects, operational anomalies) through a single imaging methodology. This multi-functional approach eliminates the need for separate test procedures for different fault types, simplifying test generation while enhancing adaptability
3Reliability
If multiple parameters are monitored simultaneously during optical scanning, then defect detection comprehensiveness is improved, but system complexity increases
Solution Approach 1:
The patent merges multiple parameter monitoring functions into a single integrated optical imaging system. By combining structural imaging, electrical state imaging, and operational parameter monitoring into one unified optical platform, the system achieves comprehensive defect detection while managing complexity through integration rather than separate systems
Solution Approach 2:
The patent introduces an optical field as an intermediary that enables simultaneous observation of multiple circuit parameters without direct electrical interference. The optical field acts as a non-invasive mediator that can capture electrical potentials, current distributions, and structural features simultaneously, improving detection comprehensiveness while keeping system complexity manageable
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces testing costs and enhances defect detection efficiency by enabling simultaneous monitoring and comparison of parameters, facilitating early identification of manufacturing issues and reducing defective device production.
Implementation Method 1
The SOM technique enables the localization of photocurrents to produce an optical beam induced current image that show junction regions and transistor logic states
Implementation Method 2
In the infrared light emission light analysis, an infrared light transmitted through a substrate silicon material is used to observe from the backside of an IC the failure mode of the circuit
Implementation Method 3
The LIVA imaging technique can be used to locate open-circuited and damaged junctions and to image transistor logic states. The LIVA images are produced by monitoring the voltage fluctuation of a constant current power supply when a laser beam is scanned over an IC
Data Source
AI summary
An embodiment relates generally to a method of testing a mixed signal device. The method includes monitoring multiple parameters of the mixed signal device and scanning the mixed signal device with an optical source. The method also includes forming multiple windows, where each window is assigned to a respective parameter. The method further includes comparing an image from a respective image to a reference image to determine an existence of an anomaly.