Photomask Pattern Generator Beam Intensity Correction
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Solution Overview
Problem
Conventional pattern generators for photomasks face defects like mura due to light intensity variations, which can be reduced but at the cost of production speed and increased costs through methods such as multiple passes and beam pitch matching.
Innovation Solution
A method that involves analyzing and correcting the characteristics of exposure beams to ensure that only beams with predetermined values are used to pattern a substrate, generating bit maps to optimize beam placement and intensity, and adjusting pattern data to prioritize beams with preferable characteristics for critical pattern areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple passes and beam pitch matching methods are used to reduce mura defects, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The patent applies preliminary action by measuring and analyzing beam characteristics before the actual pattern exposure process. A bit map is generated in advance that designates specific beams for specific grid positions based on their measured characteristics. This pre-planning allows single-pass exposure without needing multiple corrective passes, thereby maintaining high manufacturing precision while preserving productivity.
Solution Approach 2:
The patent changes parameters by selecting and designating beams based on their characteristic values (such as intensity and position accuracy). The bit map assigns beams to grid positions non-uniformly, matching beams with appropriate characteristics to specific regions. This parameter-based selection eliminates the need for uniform beam pitch and multiple passes, resolving the contradiction between precision and productivity.
2Manufacturing precision
If multiple passes and beam pitch matching methods are used to reduce mura defects, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The bit map generation and beam designation process is performed in advance before exposure. By pre-analyzing beam characteristics and creating the designation map beforehand, the complex decision-making about beam assignment is completed prior to the actual exposure process. This simplifies the exposure process itself to a single pass, reducing device complexity while maintaining precision.
Solution Approach 2:
The patent creates a digital bit map representation that copies and stores the optimal beam-to-grid assignment information. This digital model serves as a guide during exposure, replacing the need for complex real-time control and multiple physical passes. The bit map acts as a simplified intermediary that encodes the complex optimization results in an easy-to-follow format.
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 reduces mura defects without compromising production speed or increasing costs, enabling the creation of high-quality photomasks with optimized beam arrangements.
Implementation Method 1
exposing a photosensitive layer on the substrate with the plurality of beams
Data Source
AI summary
A pattern generating method includes, generating a first bit map from inputted pattern data. Characteristics of a plurality of beams for exposing a pattern on a substrate are analyzed, each of the plurality of beams being designated to correspond to one of a plurality of grids in the first bit map. The pattern data is corrected such that at least one of the plurality of beams is designated to expose at least a portion of the pattern on the substrate. A second bit map is generated from the corrected pattern data. The substrate is patterned using the plurality of beams according to the designation of the second bit map.