Line Narrowing Module Prism Rotation Mechanism
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Solution Overview
Problem
Current semiconductor exposure apparatuses face challenges in maintaining resolution due to chromatic aberrations caused by wide spectral linewidths of KrF and ArF excimer laser apparatuses, leading to decreased performance in liquid-immersion exposure processes.
Innovation Solution
A line narrowing module is introduced, comprising a prism and a grating that refract and disperse laser light, along with a rotation mechanism and elastic elements to adjust the prism's attitude, effectively narrowing the spectral width of the laser light and reducing chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a gas laser apparatus (KrF or ArF excimer laser) is used as the light source for exposure, then the wavelength can be reduced to improve resolution, but the spectral linewidth becomes wide causing chromatic aberrations that decrease resolution
Solution Approach 1:
A line narrowing module is introduced as an intermediary component between the gas laser apparatus and the projection lens. This module includes a grating and etalon that selectively transmit a narrow spectral bandwidth, thereby reducing chromatic aberrations while maintaining the beneficial short wavelength of the excimer laser light
Solution Approach 2:
The spectral linewidth parameter of the laser light is changed from wide (350-400 pm) to narrow by using the line narrowing module. This parameter change eliminates chromatic aberrations while preserving the short wavelength (248 nm for KrF, 193 nm for ArF) that enables high-resolution exposure
2Manufacturing precision
If the spectral linewidth is narrowed using a line narrowing module, then chromatic aberrations are reduced, but the device complexity increases
Solution Approach 1:
The line narrowing module is designed to perform multiple functions within a single integrated structure: the grating provides wavelength selection while the etalon provides additional spectral filtering, and the entire assembly can be rotated to adjust the linewidth. This multi-functionality reduces the need for separate components and simplifies the overall system
3Manufacturing precision
If the prism attitude is adjusted using a rotation mechanism with elastic elements, then the spectral width can be controlled, but the mechanical complexity increases
Solution Approach 1:
The elastic elements (springs) in the rotation mechanism provide automatic positioning and damping of the prism. The springs allow the prism to rotate to the desired attitude while automatically returning it to a neutral position and dampening vibrations, eliminating the need for complex active control systems or additional damping components
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 line narrowing module enhances the resolution of semiconductor exposure apparatuses by minimizing chromatic aberrations, thereby improving the precision and stability of the exposure process.
Implementation Method 1
a prism configured to refract laser light in a first plane
Implementation Method 2
a grating configured to disperse the laser light in the first plane and narrows a linewidth of the laser light
Data Source
AI summary
A line narrowing module includes a prism that refracts laser light in a first plane, a grating that disperses the laser light in the first plane, first to fourth elements, and a rotation mechanism and narrows the linewidth of the laser light. The second element is supported between the first and fourth elements by the first element. The rotation mechanism rotates the second element relative to the first element around an axis intersecting the first plane. The prism is located between the second and fourth elements and so supported by the second element that the rotation mechanism rotates the prism and the second element. The third element has elasticity and is compressed and located between the prism and the fourth element. The fourth element receives reaction force from the compressed third element. The second element is mechanically independent of the fourth element in the rotational direction of the rotation mechanism.