Charged Particle Beam Writing Position Shift Correction
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Solution Overview
Problem
Charged particle beam writing methods face challenges in accurately correcting beam irradiation position shifts caused by charging phenomena, particularly in semiconductor manufacturing, where antistatic films are not suitable and dynamic focusing electrodes can lead to contamination and decreased accuracy.
Innovation Solution
A charged particle beam writing method and apparatus that calculates and corrects beam position shifts by dividing the writing region into mesh areas, calculating pattern and dose distributions, and applying a voltage to create an electric field to manage charge distributions, thereby correcting irradiation positions without the need for antistatic films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an antistatic film is formed on the substrate to prevent charging, then beam irradiation position shift is eliminated, but manufacturing cost increases due to new facilities needed and the film is incompatible with chemically amplified resist
Solution Approach 1:
The invention extracts and eliminates the need for antistatic films by implementing charging effect correction through calculation and compensation. The system calculates charge amount distributions from direct charge and fogging charge, determines position shifts, and corrects irradiation positions computationally, thereby removing the requirement for additional antistatic film formation facilities and processes.
Solution Approach 2:
The invention replaces the physical/chemical approach of using antistatic films with a computational/electronic approach. Instead of modifying the substrate surface physically, the system uses calculation units to compute charge distributions and position shifts, then applies electronic correction to the irradiation positions, substituting mechanical/chemical means with computational methods.
2Object-affected harmful factors
If the dynamic focusing electrode is set to positive potential to prevent secondary electrons from returning to the substrate, then fogging charge is reduced, but the number of secondary electrons entering the column increases causing contamination and trajectory deviation
Solution Approach 1:
The invention converts the harmful effect of fogging charge into a useful computational parameter. Instead of trying to physically prevent fogging charge formation, the system calculates the fogging charge amount distribution based on scattered electron trajectories, convolves it with the irradiation amount distribution, and uses this calculated information to determine position shifts and apply corrections, thereby converting a harmful physical phenomenon into a computable correction parameter.
Solution Approach 2:
The invention introduces calculation and compensation as an intermediary between the electron beam irradiation process and the substrate. Rather than directly controlling electron trajectories through potential adjustments that cause side effects, the system uses computational models to predict charge distributions and position shifts, then applies corrections as an intermediary step before actual irradiation, mediating the interaction to avoid direct harmful effects.
3Ease of manufacture
If calculation and compensation methods are used to correct charging effects, then manufacturing cost is reduced by eliminating antistatic films, but beam irradiation position shift correction accuracy must be maintained
Solution Approach 1:
The invention segments the charging effect correction into distinct computational components: calculating charge amount distribution from direct charge, calculating fogging charged particle amount distribution by convolving distribution functions, combining these to determine total charge amount distribution, calculating position shifts from the charge distribution, and applying corrections. This segmentation allows each component to be optimized independently while maintaining overall accuracy.
Solution Approach 2:
The invention implements a feedback mechanism where the calculated position shifts based on charge amount distributions are used to correct irradiation positions in real-time. The system continuously calculates charge distributions from both direct and fogging charge components, determines the resulting position shifts, and applies compensatory corrections to maintain accurate beam placement, creating a closed-loop feedback system that ensures precision.
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 approach allows for high-accuracy correction of beam irradiation position shifts, improving the precision of semiconductor pattern writing and reducing manufacturing costs by eliminating the need for antistatic films.
Implementation Method 1
a charged particle beam is deflected by a deflector
Implementation Method 2
focusing is performed by an objective lens
Implementation Method 3
forming an electric field by applying a predetermined voltage to at least one of the substrate and a potential regulation member
Data Source
AI summary
The purpose of the present invention is to correct a beam irradiation position shift caused by charging phenomena with high accuracy. A charged particle beam writing method includes virtually dividing a writing region of the substrate so as to have a predetermined mesh size and calculating a pattern density distribution representing an arrangement ratio of the pattern for each mesh region, calculating a dose distribution using the pattern density distribution, calculating an irradiation amount distribution using the pattern density distribution and the dose distribution, calculating a fogging charged particle amount distribution, calculating a charge amount distribution due to direct charge and a charge amount distribution due to fogging charge, calculating a position shift of a writing position based on the charge amount distribution due to direct charge and the charge amount distribution due to fogging charge, correcting an irradiation position using the position shift, and irradiating the corrected irradiation position with the charged particle beam with which a potential of a surface of the substrate becomes higher than a potential of a bottom surface of ae potential regulation member.