MTJ Electrical Testing with On-Board Waveform Analysis

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Solution Overview

Problem

Current magnetic electrical test apparatuses for magnetic tunnel junction devices suffer from slow execution times due to communication handshaking between the computer and digitizer, leading to increased processing and memory requirements for handling large numbers of waveforms, which hampers rapid analysis and decision-making during electrical evaluation.

Innovation Solution

A stimulus/response controller is introduced, configured to generate stimulus signals and capture response signals from magnetic tunnel junction devices, featuring a communication interface for receiving instructions, a configurable function circuit for analytical operations, and memory for retaining test commands, which minimizes processing and communication overhead by performing evaluations before transmitting results.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional computer-digitizer communication handshaking is used for electrical testing, then measurement precision can be maintained, but execution time increases and productivity decreases

Engineering Contradiction:
Improveelectrical measurement precisionVSAvoidtesting execution speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system segments the testing function into independent parallel channels, with multiple digitizers operating simultaneously to capture different signal aspects. This segmentation eliminates sequential handshaking delays while maintaining measurement precision through coordinated multi-channel data acquisition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The arbitrary waveform generator pre-generates and buffers stimulus waveforms before they are needed for testing. This preliminary action allows the system to prepare test sequences in advance, eliminating real-time computation delays and enabling faster execution without compromising measurement accuracy.

Inventive Principle:
Principle #10Preliminary action

2Loss of information

If large numbers of waveforms are processed through traditional communication protocols, then complete test data can be captured, but processing overhead increases and memory requirements increase

Engineering Contradiction:
Improvetest data completenessVSAvoidprocessing and memory requirements
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The system extracts only the essential test results and critical waveform parameters from the complete waveform data, transmitting only this extracted information through the communication interface. This eliminates the need to process and transmit large volumes of raw waveform data while preserving all necessary test outcomes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system creates compact digital representations of waveform data that capture the essential test information in a condensed format. These copied representations maintain test data completeness for analysis purposes while occupying minimal memory and requiring minimal processing resources.

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3531147B1Electrical testing apparatus for spintronic devices
Publication Date: 2023.03.22 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD
  • EP3531147B1 patent drawingFigure 1A~1B
  • EP3531147B1 patent drawingFigure 2A~2B
  • EP3531147B1 patent drawingFigure 3

AI summary

A stimulus/response controller within a magnetic electrical test apparatus is configured for generating and transmitting stimulus waveforms to a high-speed DAC for application to a MTJ DUT. The response signal from the MTJ DUT is applied to an ADC that digitizes and transfers the response signal to the stimulus/response controller. The stimulus/response controller has a configurable function circuit that is selectively configured for performing evaluation and analysis of the digitized stimulus and response signals. The configurable functions are structured for performing any evaluation and analysis function for determining the characteristics of the MTJ DUT(s). Examples of the evaluation and analysis operations include averaging the stimulus and/or response signals, determining the differential resistance, the degradation times, failure counts, or the bit error rate of the MTJ DUT(s). The evaluations and analysis of the MTJ DUT are then available for transfer to a tester controller within the magnetic electrical test apparatus.