Sub-Surface Defect Review Using SEM Marking and Automated Cut Angles
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Solution Overview
Problem
Current sub-surface defect review processes in semiconductor manufacturing are inefficient due to difficulties in re-locating defects without visible fiducials, imprecise burn marks, and unknown cutting angles, leading to low success rates in cross-sectioning and high-resolution imaging.
Innovation Solution
A method and system that utilize a scanning electron microscope to re-detect defects, mark their locations with precise markers, and determine cutting angles in a partly-automated manner using design data, enabling precise alignment and cutting within a focused ion beam tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual navigation and cutting methods are used for sub-surface defect review, then flexibility in handling various defect types is maintained, but precision in re-locating defects and determining cut angles deteriorates
Solution Approach 1:
The patent introduces an intermediary coordinate system transformation process that bridges the inspection tool's coordinate system and the review tool's coordinate system. This intermediary mechanism automatically calculates and applies transformation parameters, eliminating manual navigation errors while maintaining process flexibility.
Solution Approach 2:
The patent replaces manual mechanical navigation and visual angle estimation with automated computational methods. The system uses coordinate transformation algorithms and automated angle calculation based on defect geometry, substituting human-operated mechanical processes with precision computational systems.
2Productivity
If automated defect detection is used, then detection speed is improved, but the ability to perform sub-surface review deteriorates due to lack of precise location information
Solution Approach 1:
The patent implements a feedback mechanism where automated detection results are fed into the coordinate transformation system, which then provides precise location information to the review tool. This closed-loop feedback ensures that high-speed automated detection maintains full compatibility with reliable sub-surface review.
Solution Approach 2:
The patent adds a coordinate transformation dimension that maps detection data into the review tool's spatial reference frame. This dimensional transformation enables automated detection outputs to be precisely interpreted in the context of physical sample geometry, maintaining review reliability.
3Manufacturing precision
If manual determination of cut angle is used, then adaptability to different defect geometries is maintained, but manufacturing precision of cross-sections deteriorates
Solution Approach 1:
The patent enables the system to determine optimal cut angles automatically based on defect geometry and orientation. The system self-calculates the required cut parameters using the transformed coordinate information and defect characteristics, eliminating the need for manual expert judgment while achieving higher precision.
Solution Approach 2:
The patent changes the approach from manual parameter estimation to automated parameter calculation. The system computes precise cut angle parameters based on mathematical relationships between defect orientation and optimal viewing geometry, transforming subjective manual determination into objective computational parameter generation.
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
Improves the precision and reliability of sub-surface defect review by allowing accurate re-location and cutting of defects, even in arrays without inherent fiducials, and reduces manual errors in determining cutting angles.
Implementation Method 1
A defect at a location indicated in a first results file is re-detected using a scanning electron microscope apparatus
Data Source
AI summary
One embodiment relates to a method of preparation of a sample of a substrate for sub-surface review using a scanning electron microscope apparatus. A defect at a location indicated in a first results file is re-detected, and the location of the defect is marked with at least one discrete marking point having predetermined positioning relative to the location of the defect. The location of the defect may be determined relative to the design for the device, and a cut location and a cut angle may be determined in at least a partly-automated manner using that information. Another embodiment relates to a system for preparing a sample for sub-surface review. Another embodiment relates to a method for marking a defect for review on a target substrate. Other embodiments, aspects and feature are also disclosed.