Charged Particle Beam Dose Correction for Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current charged particle beam lithography techniques face challenges in achieving high accuracy for pattern size correction due to proximity effects, fogging, and loading effects, leading to significant size variations in resist patterns, especially during the miniaturization of semiconductor devices.
Innovation Solution
A method and apparatus that calculate and apply a corrected dose for the charged particle beam, incorporating proximity effect, residual difference, fog, and loading effect corrections, using multiple calculator units to combine doses and ensure precise exposure, thereby reducing size variations and enhancing pattern uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional charged particle beam lithography is used, then the basic pattern writing function is achieved, but significant size variations occur due to proximity effects, fogging, and loading effects
Solution Approach 1:
The patent applies preliminary action by calculating and applying correction doses before the actual pattern writing process. Multiple correction calculations are performed in advance: proximity effect correction based on pattern density, fogging correction based on total irradiation dose, and loading effect correction based on etch rate variations. These corrections are predetermined and applied to the exposure dose before beam irradiation, thereby compensating for the harmful effects that would otherwise occur during the writing process.
Solution Approach 2:
The patent implements feedback mechanisms by using measured data from test patterns to refine correction calculations. The system measures actual pattern sizes and etch rates, compares them with target values, and uses this feedback information to adjust the correction dose calculations. This closed-loop approach allows the system to adapt to variations in process conditions and continuously improve pattern size accuracy.
2Manufacturing precision
If multiple correction calculations are performed to improve pattern accuracy, then manufacturing precision is enhanced, but the calculation complexity and processing time increase
Solution Approach 1:
The patent segments the correction process into distinct, independent calculation stages: proximity effect correction, fogging correction, and loading effect correction. Each correction type is calculated separately using its own specific algorithm and parameters. This segmentation allows each correction calculation to be optimized independently and makes the overall complex system more manageable and computationally efficient by avoiding the need for a single monolithic correction algorithm.
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
The solution enables higher accuracy in pattern size correction, reducing residual differences and achieving uniformity in pattern sizes, thereby improving the precision of semiconductor device manufacturing.
Implementation Method 1
The proximity effect is a phenomenon that electrons irradiated are reflected at the mask and again radiate the resist, an influence range of which is approximately ten-odd μm.
Implementation Method 2
the fogging is a multiple scattering-induced resist irradiation phenomenon that back-scatter electrons due to the proximity effect behave to jump out of the resist and scatter again at the lower plane of an electron lens barrel and then reradiate the mask
Data Source
AI summary
A method for writing a pattern on a workpiece by use of a charged particle beam, the method includes calculating a corrected dose including at least a proximity effect correction dose for correction of proximity effect, calculating a corrected residual difference-corrected dose for correcting a correction residual difference of the corrected dose, calculating a exposure dose of the charged particle beam to be corrected by the corrected dose as corrected by the correction residual difference-corrected dose, and irradiating the charged particle beam onto the workpiece in such a way as to become the exposure dose.