Contact Through-Hole Positioning via Bright Voltage Contrast Validation

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Solution Overview

Problem

In the manufacturing of 3D memory arrays, it is challenging to accurately and efficiently locate contact through-hole (CT) positions due to the rapid change in CT distribution, making it difficult to identify defective CTs using existing electronic beam inspection methods, which are time-consuming and lack precision.

Innovation Solution

A method and device that utilize a bright voltage contrast (BVC) image processing technique to determine and validate CT coordinates, including grayscale conversion, dilation, binarization, and contour analysis, to accurately locate CT positions, reducing inspection time and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electronic beam inspection is used to detect leakage on CT positions, then defect detection capability is improved, but inspection time increases significantly (half a day per wafer)

Engineering Contradiction:

Improvedefect detection capabilityVSAvoidinspection time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-establishing the golden CT layout file containing expected CT position information before inspection. This allows the system to quickly match detected BVC positions with pre-known CT locations, eliminating the need for time-consuming real-time analysis of hundreds of thousands of positions and reducing inspection time from half a day to 16 minutes per wafer.

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If CT distribution changes rapidly across multiple positions, then memory capacity increases, but matching accuracy between BVC positions and CT positions decreases

Engineering Contradiction:

Improvememory capacityVSAvoidmatching accuracy

Core Design Contradiction:

Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent implements feedback by comparing the actual BVC-detected CT positions with the expected positions from the golden CT layout file. This validation process identifies and corrects matching errors, ensuring high accuracy even when CT distribution changes rapidly across hundreds of thousands of positions in high-capacity memory devices.

Inventive Principle:

Principle #23Feedback

3Measurement precision

If manual matching of BVC positions with CT positions is performed, then identification accuracy is improved, but processing speed decreases

Engineering Contradiction:

Improveidentification accuracyVSAvoidprocessing speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces the mechanical manual matching process with an automated computer-based system that uses image processing and coordinate validation algorithms. The system automatically matches BVC positions with CT positions using the golden layout file, achieving both high identification accuracy and fast processing speed (16 minutes per wafer), eliminating the trade-off between accuracy and speed.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240177295A1Method and device for locating contact through-hole (CT) positions in memory device

Publication Date: 2024.05.30 YANGTZE MEMORY TECH CO LTD

AI summary

A method of locating contact through-hole (CT) positions in a memory device includes: obtaining a bright voltage contrast (BVC) image including a plurality of CTs in the memory device; determining CT coordinates in the BVC image; validating the CT coordinates in the BVC image based on a golden CT layout to obtain validated CT coordinates in the BVC image; and locating the CT positions in the memory device based on the validated CT coordinates in the BVC image.