Electron-Beam Lithography Corner Rounding Correction
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Solution Overview
Problem
Current electronic lithography methods face challenges in achieving precise pattern etching below 22 nm due to corner rounding and increased exposure times, which affect the critical dimensions and production yields of integrated circuits.
Innovation Solution
The method involves generating correction patterns using an automatic design model that determines the dimensions and locations of contiguous patterns and correction patterns, with a negative rescaling function and eRIF function, to optimize energy latitude and reduce proximity effects without significant dose increases, thereby correcting corner rounding and maintaining linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron beam lithography is used to achieve precise pattern etching below 22 nm, then manufacturing precision is improved, but production time increases significantly due to step-by-step exposure
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-defining correction patterns for corner rounding compensation before the actual lithography process. The system determines optimal correction parameters and generates correction patterns in advance, so that during exposure, the corrected patterns can be directly applied without real-time calculation, thus maintaining high precision while reducing production time overhead
2Manufacturing precision
If radiation dose is increased at the edge of the pattern to correct proximity effects, then manufacturing precision is improved, but exposure time increases significantly
Solution Approach 1:
The patent applies local quality by implementing spatially varying radiation doses tailored to specific regions of the pattern. Instead of uniformly increasing dose everywhere, the system calculates and applies localized dose modifications only where corner rounding occurs, with precise control over dose distribution. This allows correction of proximity effects at corners while maintaining efficient exposure times for the rest of the pattern
3Manufacturing precision
If complex optical distortion correction methods are integrated into photolithography processes, then manufacturing precision is improved, but equipment cost and development cost increase in very high proportions
Solution Approach 1:
The patent applies copying by creating a digital model or map of the optical distortions and storing correction patterns in memory. Instead of requiring complex physical hardware modifications or real-time computational resources, the system uses pre-generated correction pattern data that can be quickly retrieved and applied during lithography. This digital copying approach maintains high correction accuracy while significantly reducing equipment complexity and development costs compared to hardware-based solutions
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 effectively corrects corner rounding, maintains linearity, and reduces exposure time, enabling precise etching of patterns with critical dimensions around 35 nm, while limiting increases in IDB, LES, and EL, and allowing for cost-effective conversion of standard component libraries.
Implementation Method 1
The electron beam(s) used to perform the etching of a pattern diffuse in particular over a short distance (forward scattering or blur) in the resin and the substrate on the edges of the center of the beam
Implementation Method 2
Moreover, the electrons are completely backscattered over a long distance (backward scattering)
Data Source
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AI summary
The invention relates to a method of electron-beam lithography, especially direct-write electron-beam lithography, solving the problem of the reliability of the design of components etched with the effect of corner roundings of the adjacent patterns, especially for patterns to be etched, that have a critical dimension of 35 nm. The invention involves determining the critical patterns, determining correction patterns by removal of correction patterns having dimensions and sites selected according to the effects of outside or inside corner roundings, and etching the corrected design. Advantageously, the corrections can be made by calculating a correction model taking into account parameters of critical patterns. Advantageously, a correction of the proximity effects of said methods is carried out, by resizing the edges of the blocks to be etched in a combination optimised by the energy latitude with a modulation of the radiated doses. Advantageously, rescaling and negation functions and eRIF functions can be used to optimise the parameters and the implementation of the extrusion.