EUV Lithography Pattern Blind Assembly for Polygonal Exposure Fields
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Solution Overview
Problem
Current extreme ultraviolet lithography systems face challenges in creating densely packed parallel lines on workpieces with uniform exposure doses, as existing technologies struggle to efficiently stitch together adjacent exposure fields due to non-uniform illumination and geometric mismatches.
Innovation Solution
The system employs a pattern blind assembly that shapes the extreme ultraviolet beam to create a polygonal exposure field, allowing for overlapping of adjacent fields to achieve uniform exposure across the workpiece, with the pattern blind assembly capable of forming various polygonal shapes such as trapezoidal, diamond, and star shapes to facilitate effective stitching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional rectangular exposure fields are used in EUV lithography, then the system structure is simple, but adjacent exposure fields cannot be stitched together with uniform exposure dose due to geometric mismatches and non-uniform illumination
Solution Approach 1:
The patent divides the workpiece into multiple overlapping exposure fields arranged in a staggered pattern. Each exposure field is shaped to overlap with adjacent fields, creating a segmented illumination scheme that enables uniform dose distribution across the entire workpiece area through cumulative exposure.
Solution Approach 2:
The patent employs asymmetric polygonal exposure field shapes (such as trapezoidal or diamond-shaped fields) instead of conventional rectangular fields. This asymmetric geometry is specifically designed to create optimal overlap regions with adjacent fields, allowing the illumination intensity distribution to achieve uniform exposure dose when multiple fields are combined.
2Manufacturing precision
If polygonal exposure fields with overlapping design are implemented, then uniform exposure dose and stitching quality improve, but the pattern blind assembly and beam shaping requirements become more complex
Solution Approach 1:
The patent pre-configures the pattern blind assembly with specific polygonal aperture shapes and positioning arrangements before exposure begins. The overlap geometry and illumination intensity distribution are designed in advance to compensate for non-uniformities, allowing adjacent fields to stitch together with uniform exposure dose without requiring real-time adjustments during the exposure process.
3Manufacturing precision
If multiple passes of exposure fields are used to achieve uniform illumination, then exposure dose uniformity improves, but the total exposure time increases
Solution Approach 1:
The patent merges multiple exposure fields into a single coordinated exposure process where adjacent fields overlap and contribute simultaneously to the total exposure dose. By designing the fields to overlap with complementary intensity distributions, the system achieves uniform illumination across the workpiece in one coordinated pass rather than requiring sequential multiple passes.
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 enables the creation of densely packed parallel lines with uniform exposure doses across the workpiece, improving the stitching process and maintaining image quality by ensuring consistent illumination and geometric alignment of exposure fields.
Implementation Method 1
the pattern blind assembly shapes the extreme ultraviolet beam so that an exposure field created by the extreme ultraviolet beam on the workpiece has a substantially polygonal shape
Implementation Method 2
a projection optical assembly that creates an image of the patterning element on the workpiece to create the plurality of densely packed parallel lines on the workpiece
Data Source
AI summary
An extreme ultraviolet lithography system (10) that creates a pattern (230) having a plurality of densely packed parallel lines (232) on a workpiece (22) includes a patterning element (16); an EUV illumination system (12) that directs an extreme ultraviolet beam (13A) at the patterning element (16); a projection optical assembly (18) that directs the extreme ultraviolet beam diffracted off of the patterning element (16) at the workpiece (22); and a pattern blind assembly (26) positioned in a beam path (55) of the extreme ultraviolet beam (13A). The pattern blind assembly (26) shapes the extreme ultraviolet beam (13A) so that an exposure field (28) on the workpiece (22) has a polygonal shape.