Charged Particle Beam Writing Apparatus Proximity Fogging Correction
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Solution Overview
Problem
In charged particle beam writing for semiconductor manufacturing, existing methods face challenges in accurately correcting dimension variations due to proximity, fogging, and loading effects, particularly when trying to input correction values from outside the writing apparatus, which complicates the calculation and data handling for high-precision pattern formation.
Innovation Solution
A charged particle beam writing apparatus and method that includes units for calculating area density, fogging correction dose coefficients, and loading effect correction coefficients, allowing for the calculation and application of precise doses to correct dimension variations caused by proximity, fogging, and loading effects, using a dose modulation value that accounts for pre-calculated corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction calculation is performed for proximity effect inside the writing apparatus, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the proximity effect correction calculation from the writing apparatus and performs it externally using a separate correction tool or method. The corrected dose modulation values are then input into the writing apparatus, simplifying its internal structure while maintaining correction capabilities.
Solution Approach 2:
The proximity effect correction is performed in advance before the writing process. The correction tool calculates the necessary dose modulation values beforehand, and these pre-calculated values are then used by the writing apparatus during actual pattern formation.
2Ease of operation
If dose modulation values including proximity effect correction are input from outside the apparatus, then ease of operation is improved, but manufacturing precision deteriorates due to difficulty in performing additional correction calculations
Solution Approach 1:
The patent segments the correction process into distinct components: proximity effect correction performed externally to generate dose modulation values, and fogging effect correction performed internally by the writing apparatus using the area density calculation unit. This segmentation allows each correction type to be handled appropriately without interfering with the other.
Solution Approach 2:
The area density calculation unit acts as an intermediary within the writing apparatus. It receives the pre-corrected dose modulation values and uses them to calculate area density for fogging effect correction, bridging the external proximity effect correction with internal fogging effect correction.
3Manufacturing precision
If multiple correction calculations (proximity, fogging, loading effects) are performed, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The proximity effect correction is performed in advance using a separate correction tool, separating it from the time-critical writing process. This allows the writing apparatus to focus on fogging effect correction during operation, reducing overall processing time while maintaining multiple correction types.
Solution Approach 2:
The patent applies different correction methods to different aspects of the problem: global proximity effect correction is performed externally on the entire pattern, while local fogging effect correction is performed internally by the writing apparatus based on area density calculations for specific regions.
Data Source
AI summary
A charged particle beam writing apparatus includes an area density calculation unit to calculate a pattern area density weighted using a dose modulation value, which has previously been input from an outside and in which an amount of correction of a dimension variation due to a proximity effect has been included, a fogging correction dose coefficient calculation unit to calculate a fogging correction dose coefficient for correcting a dimension variation due to a fogging effect by using the pattern area density weighted using the dose modulation value having been input from the outside, a dose calculation unit to calculates a dose of a charged particle beam by using the fogging correction dose coefficient and the dose modulation value, and a writing unit to write a pattern on a target object with the charged particle beam of the dose.