Power Spectrum Analysis for IC Defect Screening
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Solution Overview
Problem
Current defect detection techniques for integrated circuit devices are complex, time-consuming, and costly, particularly when identifying latent defects, which can develop into failures over time, necessitating a more efficient screening method.
Innovation Solution
The method involves supplying a time-varying signal to an integrated circuit device and measuring its power spectrum, comparing it with known defect status power spectra to identify defects, using a system that includes a signal generator, spectrum analyzer, and computer system to determine defect presence and type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electrical, optical, and thermal techniques are used for defect identification, then measurement precision can be improved, but device complexity and time consumption increase significantly
Solution Approach 1:
The patent extracts only the necessary electrical characteristics (admittance, impedance, capacitance, resistance) that are directly related to defect detection, eliminating the need for complex optical and thermal testing systems. By focusing on electrical measurements alone, the system achieves sufficient measurement precision while significantly reducing overall device complexity.
Solution Approach 2:
The electrical testing system is designed to perform multiple defect detection functions using a single measurement approach. The same electrical probes and measurement circuitry can detect various types of defects (latent defects, manufacturing defects, reliability issues) through different electrical parameters, eliminating the need for separate optical and thermal testing equipment.
2Reliability
If reliability testing with high voltage and high temperature is applied, then latent defects can be detected, but production time and cost increase significantly
Solution Approach 1:
The patent performs preliminary electrical measurements on devices before they undergo stress conditions. By measuring electrical characteristics (admittance, impedance, capacitance, resistance) in the normal state and comparing them against known good and failed device profiles, the system can identify latent defects early in production without requiring time-consuming high-voltage, high-temperature reliability testing.
Solution Approach 2:
The patent replaces the mechanical/physical stress testing approach (high voltage, high temperature applications) with an electrical measurement-based detection system. Instead of subjecting devices to extreme conditions to reveal defects, the system uses electrical probes to measure intrinsic electrical characteristics that already indicate the presence of latent defects, dramatically reducing testing time while maintaining detection effectiveness.
3Measurement precision
If extensive failure analysis is performed on ICs with millions of transistors, then defect identification accuracy improves, but time consumption and cost increase
Solution Approach 1:
The patent extracts key electrical characteristics (admittance, impedance, capacitance, resistance) that serve as fingerprints for defect identification. Instead of performing extensive analysis on all millions of transistors, the system measures these four critical electrical parameters that collectively provide sufficient information to identify defects with high accuracy, dramatically improving screening efficiency.
Solution Approach 2:
The patent measures electrical characteristics under multiple conditions (different frequencies, voltages, temperatures) to extract comprehensive defect information. By varying measurement parameters and analyzing changes in admittance, impedance, capacitance, and resistance, the system achieves high defect identification accuracy through efficient parameter-based characterization rather than exhaustive transistor-by-transistor analysis.
Data Source
AI summary
A device sample is screened for defects using its power spectrum in response to a dynamic stimulus. The device sample receives a time-varying electrical signal. The power spectrum of the device sample is measured at one of the pins of the device sample. A defect in the device sample can be identified based on results of comparing the power spectrum with one or more power spectra of the device that have a known defect status.