Overlay Target Selection Using Simulated E-Beam Image Quality
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Solution Overview
Problem
Current semiconductor fabrication processes face challenges in achieving high precision and uniformity of submicron features, requiring improved monitoring and selection of optimal overlay targets for accurate overlay measurements.
Innovation Solution
A system and method that utilizes a processor and memory circuitry to simulate image data of potential overlay targets using electron beam examination systems, predicting the probability of meeting measurement quality criteria before actual manufacturing, and selecting the optimal overlay target based on simulated data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple overlay targets are manufactured on semiconductor specimens to ensure measurement quality, then measurement reliability is improved, but manufacturing complexity and time increase
Solution Approach 1:
The system performs preliminary simulation of overlay target images using electron beam examination parameters before actual manufacturing. This allows prediction of measurement quality outcomes in advance, enabling selection of optimal targets without needing to manufacture multiple candidates for testing.
Solution Approach 2:
The system creates simulated copies of electron beam examination images based on design data and system parameters. These simulated images serve as virtual prototypes to evaluate measurement quality, replacing the need for physical manufacturing and actual examination of multiple overlay targets.
2Measurement precision
If simulation and prediction processes are performed for all overlay targets before manufacturing, then selection accuracy is improved, but processing time increases
Solution Approach 1:
The system varies electron beam examination parameters (acceleration voltage, beam current, objective lens aperture) in simulations to evaluate how different conditions affect measurement quality. This allows comprehensive assessment without physical manufacturing by changing simulation parameters rather than physical targets.
Solution Approach 2:
The system replaces physical manufacturing and actual electron beam examination with computational simulation. The simulation model substitutes for the physical examination system, performing predictive analysis using design data and system parameters without requiring actual hardware operation for each target evaluation.
3Measurement precision
If actual electron beam examination is performed on all potential overlay targets, then measurement accuracy is improved, but manufacturing cost and time are increased
Solution Approach 1:
The system performs preliminary simulation and evaluation of all potential overlay targets before any physical manufacturing occurs. This advance assessment identifies the optimal target, allowing production to focus only on the selected target rather than manufacturing multiple candidates for examination.
Solution Approach 2:
The system creates virtual copies of electron beam examination results through simulation. These simulated examination results provide sufficient accuracy for target selection, replacing the need for actual electron beam examination of multiple physical targets and thereby reducing manufacturing costs and time.
Data Source
AI summary
There are provided systems and methods comprising obtaining design data of each of a plurality of given overlay targets comprising a plurality of stacked layers, using at least part of the design data to simulate image data of the given overlay target that would have been acquired by an electron beam examination system, using the image data to predict, before actual manufacturing of each given overlay target, one or more given attributes informative of quality of one or more images of the given overlay target after being manufactured according to the design data, and using the one or more given attributes determined for each given overlay target to select at least one optimal overlay target among the plurality of different overlay targets, wherein the at least one optimal overlay target is usable to be actually manufactured on the semiconductor specimen.