Multilayer Depth Analysis Using Multi-Direction Electron Beam Imaging
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Solution Overview
Problem
Current methods for evaluating the depth information of multilayer structures in semiconductor devices, such as those using Focused Ion Beam (FIB), face limitations including a narrow processing area, long evaluation time, and low accuracy, particularly in re-acquiring data and predicting inclination angles.
Innovation Solution
An analysis system that acquires depth information by capturing images of a sample from multiple directions using an electron beam, specifying observation ranges, focusing the electron beam, and generating a Working Distance (WD) profile to determine the number of layers, layer thickness, and starting depth of the multilayer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FIB is used to obtain pattern depth information, then measurement precision is improved, but productivity deteriorates due to long evaluation time and narrow processing area
Solution Approach 1:
The patent replaces the mechanical FIB processing system with an electron beam-based optical measurement system. The electron microscope captures images from multiple directions, and a calculation unit computes depth information through coordinate transformation, eliminating the need for physical material removal while maintaining measurement accuracy and significantly reducing evaluation time
Solution Approach 2:
The patent transitions from single-direction (1D) depth measurement to multi-directional (3D) imaging by capturing images from at least two different directions. This dimensional expansion allows the calculation unit to compute accurate depth information through spatial coordinate transformation, resolving the contradiction between precision and productivity
2Productivity
If mechanical polishing with inclination angle prediction is used, then productivity is improved, but measurement precision deteriorates due to prediction-based calculation
Solution Approach 1:
The patent implements a feedback mechanism where the calculation unit uses actual imaging data from multiple directions to compute and refine depth information. Instead of relying on predicted inclination angles, the system continuously adjusts depth calculations based on real image coordinates and focus positions, improving measurement precision while maintaining rapid evaluation capability
Solution Approach 2:
The patent replaces the prediction-based mechanical polishing method with an electron beam-based optical measurement system that directly captures and calculates actual depth information from multi-directional images, eliminating prediction errors while maintaining high evaluation speed
3Measurement precision
If FIB is used for data re-acquisition, then measurement precision is improved, but ease of operation deteriorates due to difficulty in re-acquiring data
Solution Approach 1:
The patent creates digital copies of the sample from multiple directions using electron beam imaging. These digital image copies can be stored and re-analyzed without physical sample manipulation, allowing easy re-acquisition of depth information by simply re-processing the stored image data through the calculation unit, thereby improving ease of operation while maintaining measurement precision
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 rapid and accurate acquisition of depth information for multilayer structures, overcoming the limitations of existing methods by allowing wider area operation, shorter evaluation times, and improved data re-acquisition ease while providing higher accuracy compared to prediction-based methods.
Implementation Method 1
acquiring a first captured image of a sample viewed from a first direction by irradiating the sample including a multilayer structure with an electron beam from the first direction
Implementation Method 2
performing focusing of the electron beam in the first direction using an objective lens on a plurality of portions of the sample within the specified observation range
Data Source
AI summary
Depth information of a multilayer structure is acquired quickly and with high accuracy. An analysis system includes (a) acquiring a first captured image of a sample SAM viewed from a first direction by irradiating the sample SAM including a multilayer structure with an electron beam EB1 from the first direction, (b) acquiring a second captured image of the sample SAM viewed from a second direction by irradiating the sample SAM with the electron beam EB1 from the second direction, in which the second direction intersects the first direction, (c) acquiring depth information of the multilayer structure using information of the sample SAM including the first captured image, the second captured image, a number of layers of the multilayer structure, a thickness of one layer or a thickness of each layer of the multilayer structure, and a depth at which a first layer of the multilayer structure starts.