Overlay Error Measurement Device Luminance Border Segmentation
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Solution Overview
Problem
Existing overlay error measurement techniques fail to accurately account for variations in pattern overlay conditions, particularly when a pattern has both overlaying and non-overlaying portions, leading to inaccuracies in semiconductor processes due to differences in luminance and depth.
Innovation Solution
An overlay error measurement device and computer program that designate regions demarcated by luminance borders on an image, allowing for accurate recognition and measurement of patterns with multiple luminance regions, using a template-based approach to correct alignment and perform border searches for precise overlay error calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pattern extraction methods are used, then measurement process is simple, but measurement precision deteriorates when patterns have varying overlay conditions
Solution Approach 1:
The patent segments the pattern recognition process into distinct steps: extracting candidate regions based on luminance border information, filtering candidates using overlay condition analysis, and performing precise measurement on validated patterns. This segmentation allows the system to handle complex varying overlay conditions while maintaining measurement precision.
Solution Approach 2:
The patent performs preliminary actions by first extracting luminance border information and identifying candidate pattern regions before conducting the actual overlay error measurement. This preliminary filtering based on luminance borders and overlay conditions ensures that only valid pattern candidates are subjected to precise measurement, improving both accuracy and efficiency.
2Difficulty of detecting and measuring
If high acceleration electron beam is used to reach buried patterns, then pattern detection capability improves, but measurement precision deteriorates due to inability to distinguish overlay variations
Solution Approach 1:
The patent introduces luminance border information as an intermediary element that mediates between the electron beam image data and the final overlay measurement. By using luminance borders to define candidate regions and overlay condition analysis as an intermediate filtering step, the system can accurately distinguish patterns with varying overlay conditions even when using high acceleration electron beams to detect buried patterns.
3Manufacturing precision
If pattern overlay variations are not considered, then measurement process is simple, but manufacturing precision deteriorates
Solution Approach 1:
The patent applies local quality analysis by examining overlay conditions specifically at candidate pattern regions identified through luminance border information. Rather than applying a uniform analysis to the entire image, the system focuses computational resources on localized regions where patterns may have varying overlay conditions, thereby improving manufacturing precision while controlling overall system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-accuracy overlay error measurement even in complex patterns with varying luminance regions, improving semiconductor process precision by accounting for both overlaying and non-overlaying portions.
Implementation Method 1
the electron beam reaches the buried pattern or the like which is not exposed on the sample surface by an increase of an acceleration energy (an energy of the beam reaching the sample) of the electron beam
Implementation Method 2
a method of measuring a pattern located at a plurality of heights by detecting backscattered electrons or the like obtained when a sample is irradiated with a high-acceleration electron beam
Data Source
AI summary
The purpose of the present invention is to provide an overlay error measurement device that is capable of accurately recognizing patterns and executing overlay error measurement, even when one pattern overlaps with another pattern in some areas but not in others. In order to do so, the present invention provides an overlay error measurement device provided with a calculating device for calculating overlay error. The overlay error measurement device is provided with an image designation device for designating a plurality of regions demarcated by luminance borders on an image. The calculating device recognizes, as a first pattern, a region in an image to be measured, corresponding to the plurality of regions demarcated by luminance borders, and uses the recognized first pattern to measure overlay error.