Solid Immersion Lens Lithography Resolution
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Solution Overview
Problem
Current lithographic processes face limitations in achieving smaller feature sizes and improved image quality due to constraints in reduction lens capabilities and radiation wavelength, particularly in semiconductor wafer patterning.
Innovation Solution
Incorporating one or more solid immersion lenses between the exposure mask and the resist film to focus radiation, enhancing the effective numerical aperture and allowing for more precise patterning of semiconductor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional reduction lenses are used to improve imaging capabilities, then the numerical aperture can be increased to some extent, but the minimum feature size and image quality are ultimately limited by physical constraints of the lenses
Solution Approach 1:
The patent changes the optical parameters of the system by introducing a solid immersion lens with high refractive index material. This changes the wavelength parameter effectively (λ/n) and the numerical aperture parameter, allowing the system to overcome the physical limits of conventional air-based reduction lenses and achieve smaller minimum feature sizes in semiconductor patterning
Solution Approach 2:
The solid immersion lens acts as an intermediary optical element between the conventional reduction lens and the photoresist. This intermediary component with high refractive index material enables the system to achieve higher effective numerical aperture and better resolution without requiring more complex conventional lens designs
2Manufacturing precision
If the wavelength of exposure radiation is reduced to improve resolution, then smaller feature sizes can be achieved, but illumination sources must produce radiation at high intensity over narrow bandwidth which constrains the available wavelengths
Solution Approach 1:
Instead of changing the physical wavelength of the radiation source, the patent changes the effective wavelength parameter by introducing it into the high refractive index medium of the solid immersion lens. This allows using existing DUV radiation sources while achieving the resolution benefits of shorter wavelengths through the effective wavelength reduction (λ/n)
3Manufacturing precision
If solid immersion lenses are positioned between the objective lens and the structure to be imaged, then the effective numerical aperture increases due to lowered effective wavelength, but this approach has been described only in the context of imaging not lithography
Solution Approach 1:
The patent adapts the solid immersion lens technology from its previous imaging-only applications to a multi-functional role in lithography. The solid immersion lens is integrated into the lithographic exposure system to perform both imaging and wavelength-effective reduction functions, enabling the system to achieve higher resolution patterning while maintaining the benefits of existing DUV radiation sources
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 improved resolution and feature size reduction in semiconductor patterning by effectively lowering the wavelength of radiation, overcoming limitations of conventional lenses and enhancing the quality of developed images.
Implementation Method 1
one or more solid immersion lenses positioned between the exposure mask and the resist film to focus radiation transmitted through the exposure mask in the resist film
Implementation Method 2
one or more solid immersion lenses positioned beneath the exposure mask to focus radiation transmitted through the exposure mask
Implementation Method 3
light transmitted from the objective lens is focused in the solid immersion lens instead of air or some other medium. This produces an attendant increase in the effective numerical aperture of the imaging system due to lowered effective wavelength, since the light is focused in the solid immersion lens where the refractive index is relatively high
Data Source
AI summary
Lithography using solid immersion lenses is disclosed. In one aspect, an apparatus is provided that includes a resist film that has a first side and a second and opposite side. One or more solid immersion lenses are positioned over the first side of the resist film. In another aspect, a method of manufacturing is provided that includes forming a resist film and exposing the resist film with radiation transmitted through one or more solid immersion lenses.