Memory Device Virtual Quality Control Using Area-Based Test Prediction

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Solution Overview

Problem

The manufacturing of memory devices faces challenges in efficiently and accurately testing for defects and process variations due to the high cost and time-consuming nature of traditional testing methods, which often render samples unusable and limit the number of tests that can be performed.

Innovation Solution

The implementation of machine learning techniques to interpolate virtual test results for devices that have not undergone certain tests, based on correlations with other sets of tests, allowing for more rapid feedback on processing parameters and improving manufacturing efficiency and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional testing methods are performed extensively to obtain accurate quality control data, then measurement precision and reliability improve, but loss of time and productivity deteriorate

Engineering Contradiction:
Improvequality control data accuracyVSAvoidtesting time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing virtual testing and interpolation of quality control data before actual physical testing. The system uses machine learning models to predict test results based on process parameters and previously collected data, allowing manufacturers to pre-determine which samples need physical testing and what thresholds to apply, thereby reducing the time required for extensive physical testing while maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements copying by creating virtual copies of test results through interpolation and machine learning predictions. Instead of physically testing every sample, the system generates virtual quality control data that replicates the information obtained from actual testing. This virtual data copying approach maintains measurement precision while significantly reducing the time and resources required for physical testing.

Inventive Principle:
Principle #26Copying

2Measurement precision

If traditional testing methods are performed extensively to obtain accurate quality control data, then measurement precision and reliability improve, but productivity deteriorates

Engineering Contradiction:
Improvequality control data accuracyVSAvoidmanufacturing throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs preliminary virtual testing and data interpolation before physical testing, allowing manufacturers to quickly assess quality control metrics without waiting for time-consuming physical tests. This preliminary action enables faster decision-making and maintains manufacturing throughput while ensuring measurement precision through subsequent targeted physical testing of only necessary samples.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By creating virtual copies of quality control data through machine learning and interpolation, the system enables rapid quality assessment that does not bottleneck manufacturing productivity. The virtual data copying allows parallel processing and faster feedback loops, maintaining both measurement precision and high manufacturing throughput.

Inventive Principle:
Principle #26Copying

3Quantity of substance

If more physical testing is performed to generate extensive test data, then quantity of data improves, but loss of substance and cost deteriorate

Engineering Contradiction:
Improvetest data volumeVSAvoidsample usability
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent applies copying by generating virtual test data that replicates the information from physical testing without consuming physical samples. The interpolation algorithms create virtual copies of quality control measurements for samples that were not physically tested, thereby increasing the volume of available test data while preserving the usability of physical samples for other purposes or for confirmatory testing.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system replaces the mechanical physical testing process with a computational virtual testing system. Instead of physically testing every sample to generate extensive data, the system uses machine learning models and interpolation algorithms to generate virtual test data, substituting computational processes for physical testing and thereby preserving sample usability while maintaining data volume.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If traditional testing methods are used to obtain quality control data, then reliability of quality control improves, but loss of time and productivity worsen

Engineering Contradiction:
Improvequality control reliabilityVSAvoidtesting cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary virtual quality control assessment using machine learning models trained on historical data and process parameters. This preliminary action provides reliable quality control insights quickly, allowing manufacturers to make rapid decisions about which samples require detailed physical testing, thereby maintaining reliability while reducing overall testing cycle time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By creating virtual copies of quality control data through interpolation, the system enables rapid reliability assessment without time-consuming physical testing of every sample. The virtual data copying maintains reliability by using robust statistical methods and machine learning models that accurately predict quality outcomes, significantly reducing testing cycle time while preserving reliability.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20240387295A1Modelling and prediction of virtual quality control data incorporating area location in the production of memory devices
Publication Date: 2024.11.21 SANDISK TECHNOLOGIES LLC
  • US20240387295A1 patent drawing
  • US20240387295A1 patent drawing
  • US20240387295A1 patent drawing

AI summary

To provide more test data during the manufacture of non-volatile memories and other integrated circuits, machine learning is used to generate virtual test values. Virtual test results are interpolated for one set of tests for devices on which the test is not performed based on correlations with other sets of tests.