Lithography Apparatus Alignment Mark Formation via Wavelength Separation
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Solution Overview
Problem
Existing photolithography processes face challenges in ensuring accurate alignment of exposure regions on a substrate due to the risk of resist scattering and becoming foreign substances during the formation of alignment marks, which can lead to failures in circuit patterns.
Innovation Solution
A lithography apparatus that forms alignment marks on a substrate using irradiation light of a different wavelength than the exposure light, allowing for precise alignment and pattern transfer without removing the resist, thereby minimizing the occurrence of foreign substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resist is removed to form the alignment mark, then the alignment mark can be formed on the substrate, but the removed resist scatters and becomes a foreign substance that may cause circuit pattern failures
Solution Approach 1:
The patent changes the wavelength parameter of the irradiation light to form alignment marks on the substrate material itself rather than removing resist. By using light with a wavelength that the substrate material absorbs but the resist does not, the substrate is processed to create alignment marks without removing the resist, thus avoiding foreign substance contamination while maintaining alignment precision
Solution Approach 2:
The patent introduces the substrate material as an intermediary medium to form alignment marks. Instead of directly removing resist to create marks, the substrate material is processed to serve as the alignment mark carrier, mediating between the alignment requirement and the resist preservation needs
2Device complexity
If the same wavelength light is used for both alignment mark formation and exposure, then the process is simplified, but the resist cannot be processed to form alignment marks without removal
Solution Approach 1:
The patent changes the wavelength parameter of the irradiation light used for alignment mark formation, making it different from the exposure light wavelength. This parameter change enables the light to be absorbed by the substrate material for processing while allowing the resist to remain intact, achieving both alignment mark formation and resist preservation without excessive process complexity
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 ensures accurate alignment and reduces the risk of pattern failures by forming alignment marks on the substrate's material rather than the resist, maintaining the resist's integrity and enhancing the reliability of the lithography process.
Implementation Method 1
The formation unit irradiates the first material with irradiation light at a wavelength that differs from that of the exposure light and forms the alignment mark on the first material by processing the first material with energy of the irradiation light
Implementation Method 2
the substrate is aligned with respect to an original on the basis of the position of the formed alignment mark, and the first region and a second region of the substrate are exposed to the light
Data Source
AI summary
A lithography apparatus includes a formation unit that forms an alignment mark on a substrate by irradiating the substrate that includes a photosensitizer with light, and a transfer unit that aligns the substrate on the basis of the position of the alignment mark and that transfers a pattern to the substrate by illuminating the photosensitizer with exposure light. The formation unit irradiates a material of a grounding of the photosensitizer with irradiation light at a wavelength that differs from that of the exposure light and forms the alignment mark on the material by processing the material with energy of the irradiation light.