Tunable Concave Mirror for Lithography Focus Control
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Solution Overview
Problem
As semiconductor devices continue to shrink in feature size, existing patterning technologies face challenges in achieving precise and defect-free patterning, leading to reduced device performance and increased defects.
Innovation Solution
The implementation of an optical lithography system with a tunable concave mirror, beam-splitter, and on-axis lens configurations that allow for finer adjustments in focus and improved image quality, enabling more accurate patterning and reduced defects through enhanced light projection and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical lithography systems are used for patterning, then the basic patterning function is achieved, but the focus precision and image quality are insufficient leading to defects
Solution Approach 1:
The patent applies dynamics by making the mirror surface tunable and adjustable during operation. The mirror curvature can be dynamically changed to correct spherical aberrations and optimize focus for different patterning conditions, enabling the system to adapt and maintain high precision across varying operational parameters
Solution Approach 2:
The patent changes physical parameters of the optical system by adjusting the mirror curvature radius and surface shape. These parameter changes allow optimization of the optical path to reduce aberrations and improve image quality, directly addressing the precision and reliability contradiction
2Productivity
If feature size is reduced to increase integration density, then more components can be integrated, but patterning accuracy and focus quality deteriorate
Solution Approach 1:
The patent implements feedback by using sensors to detect the actual focus and image quality, then using this information to adjust the mirror surface shape and curvature. This closed-loop control ensures that patterning accuracy is maintained even as feature sizes are reduced to increase integration density
Solution Approach 2:
The dynamically adjustable mirror allows the system to adapt its optical parameters for each specific patterning task, maintaining high precision regardless of the feature size being patterned, thus enabling continued scaling for higher integration density
3Device complexity
If fixed focus optical systems are used, then the system structure is simple, but the focus cannot be optimized for different patterning requirements
Solution Approach 1:
The patent introduces dynamic adjustability to the optical system through the tunable mirror, allowing focus precision to be optimized for different patterning requirements while keeping the overall system architecture relatively compact and manageable
Solution Approach 2:
The tunable mirror serves multiple functions: it acts as both a reflective element and a focus adjustment mechanism, eliminating the need for separate focus adjustment components and maintaining system simplicity while improving precision
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 solution improves the focus and image quality of the optical lithography system, allowing for finer, more accurate patterning and reducing device defects, thereby enhancing semiconductor device performance.
Implementation Method 1
directing the energy along the optical path including reflecting the energy using a tunable concave mirror
Implementation Method 2
The implementation of an optical lithography system with a tunable concave mirror, beam-splitter, and on-axis lens configurations
Data Source
AI summary
An optical lithography system for patterning semiconductor devices and a method of using the same are disclosed. In an embodiment, an apparatus includes an optical path; a prism disposed on the optical path; a lens disposed on the optical path; and a tunable mirror disposed on the optical path, the tunable mirror including a mirror having a concave surface at a front-side thereof; a rear support attached to a backside of the mirror; and a plurality of fine-adjustment screws extending from the rear support to the backside of the mirror.