Contact Through-Hole Coordinate Detection in 3D Memory Arrays
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Solution Overview
Problem
Existing methods for determining the coordinates of contact through-holes (CTs) in 3D memory arrays are inefficient and inaccurate, particularly in differentiating between charged and defective CTs, leading to increased inspection time and reduced production yield due to over-etching and shorts between gate layers.
Innovation Solution
A method involving image processing techniques such as dilation, erosion, and binarization of bright voltage contrast (BVC) images to accurately determine CT coordinates, utilizing Otsu's thresholding for grayscale separation and center of gravity calculation to enhance precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual examination methods are used to determine CT coordinates, then inspection accuracy can be maintained, but inspection time increases significantly
Solution Approach 1:
The patent replaces manual mechanical examination with an automated image processing system that uses voltage contrast images and algorithmic coordinate determination, eliminating human labor while maintaining or improving accuracy through consistent automated measurement
Solution Approach 2:
The patent creates a digital copy of the physical CT structure through voltage contrast imaging, allowing coordinate determination to be performed on the image copy rather than direct physical measurement, enabling automated processing without losing measurement fidelity
2Productivity
If existing automated methods are used to determine CT coordinates, then inspection time is reduced, but accuracy deteriorates due to inability to differentiate charged and defective CTs
Solution Approach 1:
The patent applies different analysis criteria to different regions within the CT structure by examining voltage contrast characteristics at specific locations, allowing differentiation between charged and defective CTs based on local electrical properties rather than uniform treatment
Solution Approach 2:
The patent uses voltage contrast imaging where different electrical states (charged vs. defective) produce different brightness or contrast levels in the image, enabling automated differentiation based on optical properties that correlate with electrical state
3Productivity
If etching process is not precisely controlled, then manufacturing speed increases, but manufacturing precision decreases due to over-etching and shorts
Solution Approach 1:
The patent implements a feedback mechanism where voltage contrast images provide information about the actual state of CTs, allowing the etching process to be monitored and adjusted to prevent over-etching and shorts while maintaining efficient manufacturing speeds
Data Source
AI summary
A method of determining coordinates of contact through-holes (CTs) in a memory device includes: obtaining a bright voltage contrast (BVC) image including a plurality of CTs in the memory device; converting color components in the BVC image into grayscale values to obtain a grayscale BVC image; performing a dilation process on the grayscale BVC image to obtain a dilated grayscale BVC image; calculating a first threshold for the dilated grayscale BVC image and determining whether the first threshold is greater than or equal to a pre-determined value; in response to the first threshold being greater than or equal to the pre-determined value, performing a first image process on the dilated grayscale BVC image to obtain coordinates of each CT; and in response to the first threshold being smaller than the pre-determined value, performing a second image process on the dilated grayscale BVC image to obtain the coordinates of each CT.