1D EUV Lithography System for Dense Line Patterning
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Solution Overview
Problem
Current EUV lithographic systems are complex and costly due to their 2D nature, requiring scanning mechanisms, high optical power, and sensitivity to reticle defects, making them inefficient for printing dense line patterns with high resolution and accuracy.
Innovation Solution
A dedicated 1D EUV exposure tool that uses a fixed reticle stage and simplified optical system to image straight lines on a substrate, reducing the number of optical components and eliminating the need for scanning, while enhancing illumination efficiency through faceted fly's eye reflectors and a blind field stop for consistent exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 2D scanning system is used to image arbitrary patterns, then manufacturing versatility is improved, but device complexity increases and productivity decreases
Solution Approach 1:
The patent segments the imaging task by using multiple fixed 1D exposure fields that can be stitched together to form a complete 2D pattern. Each field is imaged separately through a simplified fixed optical system, avoiding the need for complex scanning mechanisms while achieving comprehensive pattern coverage through systematic arrangement of multiple fields.
Solution Approach 2:
The patent transitions from a single 2D imaging problem to multiple 1D imaging problems arranged in a 2D array. By decomposing the 2D pattern into multiple 1D lines imaged in different fields, the system achieves 2D pattern capability through 1D optical sections, reducing the complexity of each individual imaging channel.
2Adaptability or versatility
If a 2D scanning system with multiple moving stages is used, then arbitrary pattern transfer is achieved, but productivity decreases due to limited EUV light transmission
Solution Approach 1:
The patent divides the exposure task into multiple independent 1D fields that can be simultaneously or sequentially exposed without requiring complex synchronized scanning. This segmentation allows the system to achieve complete pattern transfer through simpler, faster 1D imaging operations, improving throughput while maintaining accuracy.
Solution Approach 2:
The fixed optical system enables continuous exposure operation without the interruption and alignment overhead associated with scanning mechanisms. By eliminating moving stages and their associated synchronization requirements, the system maintains continuous useful action during exposure, significantly improving productivity.
3Illumination intensity
If high optical power is used in 2D EUV systems, then illumination intensity is improved, but energy consumption increases
Solution Approach 1:
The patent segments the illumination requirement across multiple 1D fields rather than concentrating high power in a single 2D field. Each field receives sufficient illumination for accurate imaging, but the total power requirement is distributed and reduced compared to illuminating a complete 2D pattern with the same intensity level.
Solution Approach 2:
The system applies illumination selectively to only the active 1D line being exposed in each field, rather than illuminating the entire 2D reticle area. This partial action approach reduces total energy consumption while maintaining sufficient illumination intensity where needed for high-resolution imaging.
4Adaptability or versatility
If a complex 2D optical system with multiple mirrors is used, then arbitrary pattern imaging is achieved, but manufacturing cost increases
Solution Approach 1:
The patent segments the optical system into multiple simple 1D imaging channels rather than one complex 2D imaging system. Each channel requires fewer mirrors and simpler alignment, reducing individual component costs and assembly complexity while achieving comprehensive pattern capability through the array of fields.
Solution Approach 2:
Instead of using a single complex 2D optical system, the patent inverts the approach by using multiple simple 1D systems arranged to cover 2D space. This inversion simplifies each optical channel, making manufacturing and alignment more economical while achieving the same versatile pattern imaging capability.
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
The 1D EUV system achieves cost-effective high-resolution printing of dense line patterns with reduced optical power requirements and improved tolerance to reticle defects, enabling efficient production of advanced semiconductor features with increased throughput.
Implementation Method 1
faceted fly's eye reflectors
Implementation Method 2
projection objective configured to image the reticle pattern onto a substrate
Data Source
AI summary
Extreme ultra-violet (EUV) lithography ruling engine specifically configured to print one-dimensional lines on a target workpiece includes source of EUV radiation; a pattern-source defining 1D pattern; an illumination unit (IU) configured to irradiate the pattern-source; and projection optics (PO) configured to optically image, with a reduction factor N>1, the 1D pattern on image surface that is optically-conjugate to the 1D pattern. Irradiation of the pattern-source can be on-axis or off-axis. While 1D pattern has first spatial frequency, its optical image has second spatial frequency that is at least twice the first spatial frequency. The pattern-source can be flat or curved. The IU may include a relay reflector. A PO's reflector may include multiple spatially-distinct reflecting elements aggregately forming such reflector. The engine is configured to not allow formation of optical image of any 2D pattern that has spatial resolution substantially equal to a pitch of the 1D pattern of the pattern-source.