Multi-Beam Lithography Dose Compensation for CD Error
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Solution Overview
Problem
The challenge in patterning workpieces using multiple exposure beams is the increased Critical Dimension (CD)-error and feature roughness, particularly due to deviations in the distance between adjacent exposure beams, which can result in uniformity issues and edge roughness in the pattern.
Innovation Solution
The method involves compensating for deviations in the distance between adjacent exposure beams by adjusting the dose of the exposure beams, specifically during the patterning process, to reduce CD-errors and ensure uniform line widths. This is achieved by determining the actual position of each beam relative to a reference beam and adjusting the exposure dose, particularly when printing edge features, and varying the compensation along strips of exposure beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple exposure beams are used to increase writing speed, then productivity is improved, but manufacturing precision deteriorates due to increased CD-error and feature roughness
Solution Approach 1:
The patent applies local quality by adjusting the exposure dose individually for each exposure beam based on its specific positional deviation from the nominal position. Instead of uniform treatment, each beam receives a customized dose compensation tailored to its local positioning error, thereby maintaining pattern uniformity across all beams while achieving high-speed multi-beam writing.
Solution Approach 2:
The patent changes the exposure dose parameter for each beam based on measured positional deviations. By dynamically adjusting the dose parameter in response to actual beam positions, the system compensates for positioning errors and maintains manufacturing precision while utilizing multiple beams for increased productivity.
2Productivity
If multiple exposure beams are used to increase writing speed, then productivity is improved, but manufacturing precision deteriorates due to increased feature roughness
Solution Approach 1:
The patent addresses feature roughness by applying local quality through individualized dose adjustments for each exposure beam. Each beam's dose is optimized based on its specific positional deviation, ensuring that all beams contribute uniformly to the pattern formation and minimizing edge roughness caused by positional variations.
Solution Approach 2:
The patent reduces feature roughness by changing the exposure dose parameter for each beam according to its measured positional deviation. This dynamic parameter adjustment ensures that beams at different positions all produce features with consistent quality, eliminating the roughness that would otherwise result from uniform dosing of misaligned beams.
3Manufacturing precision
If the exposure dose is adjusted to compensate for beam position deviations, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements feedback by measuring the actual position of each exposure beam and using this information to adjust the exposure dose accordingly. This closed-loop approach automatically compensates for positioning errors, improving pattern uniformity without requiring complex mechanical adjustments or manual intervention.
Solution Approach 2:
The patent replaces potential mechanical adjustment mechanisms with a computational approach. Instead of physically repositioning beams or using complex mechanical dose control, the system uses software-based dose calculation and control, substituting mechanical complexity with computational processing to achieve the same precision goal.
Data Source
AI summary
An aspect of the present invention includes a method for patterning a workpiece covered at least partly with a layer sensitive to electromagnetic radiation by simultaneously using a plurality of exposure beams. In an example embodiment it is determined if any of the beams have an actual position relative to a reference beam which differs from its intended position. An adjustment of the exposure dose for a wrongly positioned beam is performed if said beam is printed at en edge of a feature. Other aspects of the present invention are reflected in the detailed description, figures and claims.