SEM-CSI Coordinate Mapping for Multilayer Depth Measurement
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Solution Overview
Problem
Current methods for evaluating the depth information of multi-layered semiconductor structures are either slow and inaccurate or require extensive processing time, especially when using focused ion beams, and struggle with high throughput due to the need to identify layers one by one.
Innovation Solution
An analysis system that combines 3-dimensional coordinate information from a top surface shape measurement apparatus with 2-dimensional coordinate information from a charged particle beam apparatus through coordinate conversion, enabling quick and accurate acquisition of depth information without relying on focused ion beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FIB is used to obtain depth information of patterns, then measurement precision is improved, but productivity deteriorates due to narrow processing region and time-consuming evaluation
Solution Approach 1:
The patent combines FIB processing with SEM observation in a dual-beam apparatus, allowing simultaneous or coordinated operation of both systems. The FIB creates cross-sectional surfaces while the SEM observes and measures depth information, merging the advantages of both techniques to achieve high precision without sacrificing productivity
Solution Approach 2:
The patent introduces an optical measurement system as an intermediary to measure depth information optically after FIB processing. This intermediary measurement method avoids the time-consuming nature of FIB-based depth measurement while maintaining accuracy, as the optical system can quickly scan and measure the FIB-prepared surfaces
2Measurement precision
If FIB is used to process multi-layered structures, then measurement precision is improved, but productivity deteriorates due to need to identify layers one by one
Solution Approach 1:
The patent applies preliminary FIB processing to create cross-sectional surfaces that expose multiple layers simultaneously. By pre-processing the sample to create an accessible cross-section, subsequent optical measurement can quickly identify and measure multiple layers in parallel rather than requiring sequential FIB processing for each layer
Solution Approach 2:
The patent replaces the mechanical FIB-based depth measurement with an optical measurement system. The optical system uses light interference or other optical phenomena to measure depth information non-contact and rapidly, substituting the slow mechanical scanning of FIB with fast optical detection that can handle multi-layered structures efficiently
3Productivity
If mechanical polishing is used to obtain depth information, then productivity is improved through rapid evaluation, but measurement precision deteriorates since depth information cannot be calculated except for prediction
Solution Approach 1:
The patent applies preliminary mechanical polishing to create a generally flat surface for rapid optical measurement, then uses targeted FIB processing at specific locations to create precise cross-sectional references. This preliminary polishing enables fast optical scanning while the selective FIB processing provides accurate reference points for calibration
Solution Approach 2:
The patent implements a feedback mechanism where optical measurement results are continuously compared with FIB-created reference structures. The optical system's depth measurements are calibrated and corrected using the known geometries created by FIB, providing real-time feedback that improves measurement precision while maintaining the speed of optical measurement
Data Source
AI summary
A technology capable of acquiring depth information of a sample quickly and accurately is provided. A computer system in an analysis system acquires 3-dimensional coordinate information of a top surface shape of a sample having a stacking structure, the 3-dimensional coordinate information being measured by a top surface shape measurement apparatus (CSI), acquires 2-dimensional coordinate information based on a photographic image of the sample imaged by a charged particle beam apparatus (SEM), performs coordinate conversion for association between the 3-dimensional coordinate information of the CSI and the 2-dimensional coordinate information of the SEM and acquires association data which is a result, and acquires depth information on a coordinate system of the SEM based on the association data.