Multiple Electron Beam Inspection Correction Circuit
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Solution Overview
Problem
Existing multiple electron beam inspection apparatuses face challenges in achieving precise inspections due to shape and size differences between primary electron beams, leading to inaccuracies in comparing inspection images acquired with different beams, which affects the detection of pattern defects in semiconductor wafers and masks.
Innovation Solution
A multiple electron beam inspection apparatus and method that includes a secondary electron image acquisition mechanism and a correction circuit to adjust partial secondary electron images to resemble images acquired with a uniform beam, ensuring consistency across all primary electron beams by equalizing their shapes and sizes, allowing for accurate inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple primary electron beams are used for inspection, then inspection coverage and productivity are improved, but differences in beam shape and size cause measurement precision to deteriorate
Solution Approach 1:
The patent applies parameter changes by adjusting the beam shape and size parameters of each primary electron beam through individual correction functions. The correction circuit modifies beam parameters (shape, size) to make them uniform across all beams, thereby resolving the measurement precision issue while maintaining the productivity benefit of using multiple beams
Solution Approach 2:
The patent creates a reference image using a uniform beam that copies the ideal inspection conditions. Each primary beam's image is then compared against this reference, allowing the system to maintain high measurement precision by using the reference copy as a standard for accurate defect detection
2Device complexity
If beam shape and size differences are not corrected, then device complexity is reduced, but manufacturing precision of inspection results deteriorates
Solution Approach 1:
The patent implements preliminary action by pre-calculating and storing correction functions for each primary beam before actual inspection. The correction functions are determined in advance based on beam characteristics, so during inspection the system can efficiently apply these pre-prepared corrections without adding significant complexity to the inspection process
Solution Approach 2:
The correction circuit acts as an intermediary between the multiple primary beams and the image comparison process. It mediates the beam differences by applying individual correction functions to each beam's image, transforming non-uniform beam images into uniform images that can be accurately compared for defect detection
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
This solution enables precise inspection by aligning inspection images acquired with different beams to a uniform standard, reducing false defects and enhancing the accuracy of pattern defect detection on semiconductor wafers and masks.
Implementation Method 1
a secondary electron image acquisition mechanism that acquires a secondary electron image by applying multiple primary electron beams to a substrate where figure patterns are formed, and detecting multiple secondary electron beams emitted from the substrate by irradiation with the multiple primary electron beams
Data Source
AI summary
A multiple electron beam inspection apparatus includes a correction circuit that corrects a partial secondary electron image of partial secondary electron images configuring a secondary electron image and obtained by irradiation with a corresponding primary electron beam of the multiple primary electron beams such that the partial secondary electron image becomes close to a uniform beam partial image when an irradiation region of a primary electron beam corresponding to the partial secondary electron image is irradiated with a uniform beam obtained by equalizing shapes and sizes of all primary electron beams, by using a function for individual correction of each primary electron beam, for each of the plural partial secondary electron images, and an inspection circuit that performs inspection using plural partial secondary electron images each corrected.