Lithography Dose Modulation for Proximity Effect Correction
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Solution Overview
Problem
Current photolithography methods face challenges in correcting optical distortions for critical dimensions less than 50 nm, leading to increased costs and exposure times, while electronic lithography struggles with proximity effects and long production times due to high radiation doses required for pattern fidelity.
Innovation Solution
A method optimizing the energy and area of electronic radiation applied, involving dose modulation and pattern adjustments based on process energy latitude, using convolution and sensitivity threshold calculations to reduce radiation doses and exposure times, and incorporating automation in design tools for efficient correction of proximity effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If radiation dose is increased to correct proximity effects and maintain pattern fidelity, then manufacturing precision is improved, but exposure time increases significantly
Solution Approach 1:
The patent applies local quality by differentiating the radiation dose based on spatial location within the pattern. Areas experiencing proximity effects receive increased dose while other areas receive standard or reduced dose, optimizing both pattern fidelity and exposure time through location-specific dose modulation.
Solution Approach 2:
The patent changes the radiation dose parameter dynamically based on the calculated proximity effect magnitude at each location. By modulating the dose parameter in response to measured or calculated proximity effects, the system maintains pattern fidelity while minimizing unnecessary exposure time increases.
2Manufacturing precision
If complex optical distortion corrections are incorporated in photolithography, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex optical correction mechanisms with a computational approach. Instead of using complex optical elements or multiple exposure steps, the system uses software-based proximity effect calculation and dose modulation algorithms to achieve the same correction goal, thereby reducing equipment complexity and cost.
3Manufacturing precision
If radiation dose is increased to ensure pattern fidelity in electronic lithography, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent applies local quality by differentiating the radiation dose based on spatial location within the pattern. Areas experiencing proximity effects receive increased dose while other areas receive standard or reduced dose, optimizing both pattern fidelity and exposure time through location-specific dose modulation.
Solution Approach 2:
The patent applies partial action by increasing radiation dose only in specific areas where proximity effects occur, rather than uniformly increasing the dose across the entire pattern. This selective approach maintains pattern fidelity in critical areas while minimizing the overall exposure time and preserving productivity.
Data Source
AI summary
A lithography method for a pattern to be etched on a support, notably to a method using electron radiation with direct writing on the support. Hitherto, the methods for correcting the proximity effects for dense network geometries (line spacings of 10 to 30 nm) have been reflected in a significant increase in the radiated doses and therefore in the exposure time. According to the invention, the patterns to be etched are modified as a function of the energy latitude of the process, which allows a reduction of the radiated doses.