Multi-Beam Writing Grid Optimization for Mask CD Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current multi-beam writing technologies face challenges in reducing writing time for non-critical pattern areas while maintaining low Critical Dimension (CD) and Local/Global CD Uniformity (LCDU/GCDU) values, especially in photomask substrates where non-critical patterns require less precise exposure.
Innovation Solution
The method involves differentiating between primary and secondary pattern regions, using coarser exposure grids and adjusted dose levels for non-critical areas, and incorporating indirect exposure effects to reduce writing time without compromising CD uniformity, by employing a 'Single-Centered Grid' and strategic dose distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine exposure grid is used for writing non-critical pattern areas, then CD uniformity is maintained, but writing time increases
Solution Approach 1:
The patent applies different exposure grid configurations to different regions of the pattern area. A fine exposure grid is used for primary pattern areas requiring high precision, while a coarse exposure grid is used for secondary non-critical pattern areas. This local differentiation allows the system to maintain CD uniformity where needed while significantly reducing writing time in non-critical regions, thereby resolving the contradiction between manufacturing precision and productivity.
2Productivity
If a coarse exposure grid is used to reduce writing time, then productivity increases, but CD uniformity deteriorates
Solution Approach 1:
The patent implements region-specific grid configurations where the exposure grid spacing is adapted to the criticality of each pattern area. Secondary non-critical areas use larger grid spacing to accelerate writing, while primary areas maintain fine grid spacing for precision. This localized approach ensures that CD uniformity is preserved in critical regions while achieving productivity gains in non-critical regions.
Solution Approach 2:
The pattern area is segmented into primary and secondary regions with different exposure requirements. By dividing the writing field into distinct zones and applying appropriate grid configurations to each segment, the system optimizes the balance between writing speed and precision for different functional areas, resolving the contradiction between overall productivity and local CD uniformity.
3Productivity
If indirect exposure effects are incorporated for non-critical areas, then writing efficiency improves, but process complexity increases
Solution Approach 1:
The patent incorporates indirect exposure effects by pre-calculating and applying dose compensation factors to secondary pattern areas before the actual writing process. This preliminary action accounts for scattered particle effects that would otherwise require finer grid spacing and longer writing times. By preparing these corrections in advance, the system achieves writing efficiency improvements without significantly increasing real-time process complexity.
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 significantly reduces multi-beam writing time for non-critical patterns while maintaining precise CD and uniformity, allowing for faster processing without sacrificing accuracy, and enhances printing efficiency by optimizing exposure doses and grid layouts.
Implementation Method 1
a method for irradiating a target with a beam of energetic radiation formed by electrically charged particles
Data Source
AI summary
To irradiate a target with a beam of energetic electrically charged particles, the beam is formed and imaged onto a target, where it generates a pattern image composed of pixels. For a pattern which comprises a primary pattern region to be written with a predetermined primary feature size and a secondary pattern region which is composed of structure features capable of being written with a secondary feature size, larger than the primary feature size. The structure features of the primary pattern region are written by exposing a plurality of exposure spots on grid positions of a first exposure grid; the structure features in the secondary pattern region are written by exposing a plurality of exposure spots on grid positions of a second exposure grid according to a second arrangement which is coarser that the regular arrangement of the first exposure grid.