Mask Pattern Shifting for Lithography Line Waviness
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Solution Overview
Problem
Conventional digital lithography systems suffer from line waviness in mask patterns, leading to lower quality display devices, particularly in the manufacturing of semiconductor and LCD components.
Innovation Solution
A method is introduced where mask pattern data is shifted between a minimum and maximum shift at a specific frequency during the digital lithography process, using a processing unit with multiple image projection systems to project exposure polygons onto a substrate, ensuring each shot is within the exposure polygon and aligning subsequent shots vertically to reduce line waviness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional digital lithography systems project mask patterns directly onto substrates, then the lithography process is simple and fast, but line waviness occurs in the mask patterns reducing pattern precision
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple shifted versions of mask pattern data (first shifted mask pattern data, second shifted mask pattern data, etc.) before the actual lithography process. During exposure, the system selectively applies these pre-prepared shifted patterns based on real-time substrate position feedback, avoiding the need for complex real-time calculations while achieving reduced line waviness.
Solution Approach 2:
The patent implements dynamics by making the mask pattern shifting amount variable and adaptive. Instead of using a fixed shift amount, the system dynamically adjusts the shifting based on the actual substrate position relative to the ideal position, allowing the lithography system to compensate for position variations and reduce line waviness while maintaining pattern accuracy.
2Manufacturing precision
If mask pattern data is shifted at high frequency to reduce line waviness, then pattern precision improves, but processing time increases
Solution Approach 1:
The patent resolves this contradiction by pre-calculating multiple shifted mask pattern versions (first shifted, second shifted, etc.) before the lithography process begins. This preliminary preparation allows the system to quickly select and apply the appropriate shifted pattern during exposure without performing complex real-time calculations, thus reducing processing time while maintaining line waviness reduction effectiveness.
Solution Approach 2:
The patent applies periodic action by using a predetermined shifting frequency that corresponds to the substrate scanning speed and pattern requirements. The mask pattern data is shifted at this optimized periodic rate, which is sufficient to reduce line waviness but not so high as to unnecessarily increase processing time, achieving an optimal balance between precision and efficiency.
3Area of stationary object
If multiple image projection systems are used to cover large substrate areas, then substrate coverage increases, but line waviness becomes more pronounced
Solution Approach 1:
The patent applies segmentation by dividing the large substrate area into multiple exposure polygons, each handled by a separate image projection system. The mask pattern data is differentially shifted for each exposure polygon based on its specific position and orientation, allowing each segment to be optimized independently. This segmented approach maintains pattern straightness across the entire large substrate while utilizing multiple projection systems for full coverage.
Solution Approach 2:
The patent implements local quality by applying different shifting amounts and directions to different exposure polygons based on their local characteristics. Each exposure polygon receives a customized shifted mask pattern tailored to its specific position and orientation on the substrate, ensuring optimal pattern straightness for each local region while maintaining overall substrate coverage.
Data Source
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AI summary
Embodiments described herein provide a method shifting mask pattern data during a digital lithography process to reduce line waviness of an exposed pattern. The method includes providing a mask pattern data having a plurality of exposure polygons to a processing unit of a digital lithography system. The processing unit has a plurality of image projection systems that receive the mask pattern data. Each image projection system corresponds to a portion of a plurality of portions of a substrate and receives an exposure polygon corresponding to the portion. The substrate is scanned under the plurality of image projection systems and pluralities of shots are projected to the plurality of portions while shifting the mask pattern data. Each shot of the pluralities of shots is inside the exposure polygon corresponding to the portion.