Semiconductor Structure Calibration From Milled 3D Image Transformations
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Solution Overview
Problem
The challenge of determining and analyzing semiconductor structures with high precision is exacerbated by increasing complexity and dimensions, particularly in 3D semiconductor structures, where image distortions and sample rotations complicate accurate measurement and calibration.
Innovation Solution
A method involving the determination of a representative ground truth structure through milling or delayering, followed by image transformation to correct for distortions, allowing for precise calibration and inspection of further structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If charged particle beam imaging is used for 3D analysis of semiconductor structures, then measurement capability in three dimensions is improved, but image distortions and sample rotations cause measurement precision to deteriorate
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements on a reference sample with known ground truth structures before analyzing the actual semiconductor structures. This preliminary calibration establishes transformation parameters that correct for image distortions and sample rotations, thereby improving measurement precision while maintaining 3D measurement capability
Solution Approach 2:
The patent implements feedback by comparing the imaged ground truth structures with their known reference structures, calculating transformation parameters based on the deviations observed, and then applying these parameters to correct subsequent measurements. This closed-loop feedback mechanism systematically eliminates measurement errors caused by distortions and rotations
2Manufacturing precision
If milling is performed to obtain cross-section images of structures at different positions, then 3D structure analysis is improved, but device complexity and processing time increase
Solution Approach 1:
The patent uses milling to create cross-section images that serve as copies of the 3D structures at different depth positions. By acquiring multiple 2D cross-sectional copies and combining them with transformation parameters, the system reconstructs the 3D structure with high precision without requiring complex real-time 3D imaging equipment
3Measurement precision
If transformation parameters are determined through calibration with ground truth structures, then calibration accuracy is improved, but loss of time occurs during the calibration process
Solution Approach 1:
The calibration process is performed as a preliminary action using reference samples with known ground truth structures before actual production measurements are taken. This upfront calibration investment establishes accurate transformation parameters that can be reused, thereby improving calibration accuracy while minimizing time loss in subsequent measurements
Data Source
AI summary
A method comprises determining a representative ground truth structure provided in a semiconductor sample having a plurality of structures extending mainly in a thickness direction of the sample in a region of interest containing the plurality of structures. At least one adapted image of a milled sample is determined, wherein the at least one adapted image comprises image representations of the structures in the region of interest at different positions in the thickness direction. A transformation is determined by which the image representations at the different positions in the thickness direction of the structures build the ground truth structure, and the transformation is stored for a future application of the transformation to a further sample having the plurality of structures.