Charged Particle Beam Drawing Method for Resist Film Thickness Correction
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Solution Overview
Problem
The increasing miniaturization of semiconductor devices requires more accurate calculation of resist film thickness after etching and correction of electron beam irradiation dose to maintain pattern dimension accuracy, as existing methods struggle with macroscopic dimensional variations and resist film thickness variations during the lithography process.
Innovation Solution
A charged particle beam drawing method that calculates the resist film reduction amount based on the resist area rate and initial thickness, creates a dimension correction map to estimate the remaining resist film thickness, and synthesizes this with a second dimension correction map to accurately determine the irradiation dose for electron beam application, ensuring precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the electron beam irradiation dose is corrected based on the resist film thickness after etching, then the pattern dimension accuracy is improved, but the calculation complexity of the resist film thickness increases
Solution Approach 1:
The patent performs preliminary measurements of the resist film thickness after etching at multiple positions before the actual electron beam drawing process. Based on these preliminary measurements, a dimension correction map is pre-calculated and stored. During the actual drawing process, this pre-calculated correction map is applied directly, avoiding the need to perform complex thickness calculations in real-time, thus reducing calculation complexity while maintaining high pattern dimension accuracy.
2Manufacturing precision
If the resist film thickness measurement is performed at multiple positions to account for macroscopic dimensional variations, then the drawing accuracy is improved, but the measurement time increases
Solution Approach 1:
The patent performs resist film thickness measurements at multiple positions during a preliminary measurement stage before the actual drawing process. This allows comprehensive data collection for accurate dimension correction maps without impacting the time required for the main drawing operation. The measurement data is processed offline to create correction maps that are then applied during high-speed drawing.
Solution Approach 2:
The patent implements a dynamic correction approach where the dimension correction map is created based on actual measured thickness distribution of the resist film. This dynamic adjustment allows the system to adapt to variations in resist film thickness across the substrate, accounting for macroscopic dimensional variations, thereby improving drawing accuracy without requiring real-time measurements during the drawing process itself.
3Manufacturing precision
If the dimension correction map is created based on the actual resist film thickness distribution, then the pattern dimension accuracy is improved, but the process complexity increases
Solution Approach 1:
The patent performs preliminary measurements of the resist film thickness at multiple positions before the actual electron beam drawing process. Based on these preliminary measurements, a dimension correction map is pre-calculated and stored. During the actual drawing process, this pre-calculated correction map is applied directly, avoiding the need to perform complex thickness calculations in real-time, thus reducing calculation complexity while maintaining high pattern dimension accuracy.
Solution Approach 2:
The patent creates a dimension correction map that represents the actual resist film thickness distribution across the substrate. This correction map serves as a simplified model or copy of the complex physical thickness variations, allowing the system to apply corrections based on pre-analyzed data rather than performing complex real-time calculations during the drawing process.
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 method enhances drawing accuracy by accurately calculating the resist film thickness and correcting the electron beam irradiation dose, effectively addressing macroscopic dimensional variations and maintaining pattern precision across the semiconductor substrate.
Implementation Method 1
irradiating a resist film on a substrate with a charged particle beam, forming a resist pattern
Implementation Method 2
irradiating the resist film with an electronic beam, and by performing a development process
Implementation Method 3
etching a light-shielding film lying under the resist film with the resist pattern used as a mask
Data Source
AI summary
In one embodiment, a charged particle beam drawing method includes calculating a resist film reduction amount caused by etching from data representing a relation between a resist area rate and a resist film reduction amount and from an area rate of a pattern to be drawn, calculating a remaining resist-film thickness distribution by employing both an initial thickness of the resist film and the resist film reduction amount, estimating a dimension distribution of the light-shielding film pattern from the remaining resist-film thickness distribution, creating a first dimension correction map by determining a dimension correction amount from the estimated dimension distribution, creating a third dimension correction map by synthesizing a second dimension correction map to correct a relatively macroscopic dimensional variation and the first dimension correction map, and calculating an irradiation dose of the charged particle beam by employing the third dimension correction map.