Exposure Apparatus Optical Axis Alignment via Integrated Diaphragm
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Solution Overview
Problem
Conventional exposure apparatuses face challenges in maintaining optical axis alignment and telecentricity due to positional and angular shifts caused by changes in light source units, leading to increased bulkiness and complexity with dedicated monitoring systems.
Innovation Solution
An exposure apparatus with a diffraction optical element, a condensing optical system, and a diaphragm mechanism that adjusts the incident angle by using a controller to detect deviations and correct them without the need for a separate monitoring system, thereby maintaining optical axis alignment and suppressing apparatus size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated monitor and monitoring optical system are used to detect optical axis shift, then measurement precision is improved, but device complexity increases and apparatus size increases
Solution Approach 1:
The patent combines the exposure optical system and monitoring functions into a single integrated system. The exposure light itself is used for monitoring by detecting its reflection from the substrate, eliminating the need for separate dedicated monitors and monitoring optical paths. This merging approach maintains measurement precision while reducing device complexity.
Solution Approach 2:
The exposure light serves dual purposes: it performs the primary exposure function and simultaneously provides monitoring information through its reflection. The same optical path is used for both exposure and alignment detection, making the system multi-functional and eliminating redundant components.
2Measurement precision
If a dedicated monitor and monitoring optical system are used to detect optical axis shift, then measurement precision is improved, but apparatus size increases
Solution Approach 1:
The patent merges the monitoring function into the existing exposure optical path by detecting the reflection of exposure light from the substrate. This eliminates the need for separate monitoring optical systems and reduces the overall apparatus volume while maintaining detection precision.
Solution Approach 2:
The exposure light performs dual functions: exposing the substrate and providing alignment monitoring information through reflection. This multi-functionality eliminates redundant optical components and reduces apparatus size.
3Measurement precision
If exposure light is branched to guide it to a monitor optical system, then optical axis detection is enabled, but device complexity increases
Solution Approach 1:
The patent extracts the monitoring function from a separate optical path and integrates it into the main exposure path by detecting the reflection of exposure light from the substrate. This eliminates the need to branch the optical path to a separate monitor system.
Solution Approach 2:
The exposure light is used for both exposure and monitoring purposes. By detecting the reflected light from the substrate, the system achieves optical axis detection without creating separate monitoring optical paths.
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 allows for precise adjustment of the illumination optical system, improving image performance and reducing apparatus size by eliminating the need for bulky monitoring systems, thus enhancing resolution and throughput while maintaining high precision.
Implementation Method 1
a diffraction optical element provided in an optical path between the light source and the original
Implementation Method 2
a condensing optical system configured to condense a light beam that exited from the diffraction optical element
Data Source
AI summary
An exposure apparatus is provided. An illumination optical system in the apparatus includes a diffraction optical element, a condensing optical system a detector that detects a light beam that exited from the condensing optical system, and a first diaphragm that can be inserted/removed in/from a position near a predetermined plane in an optical path where the condensing optical system condenses a light beam. The first diaphragm has an opening diameter such that an output of the detector decreases when an incident angle of light from a light source on the diffraction optical element deviates from a target angle. Based on an output of the detector when the first diaphragm is inserted in the position and an output of the detector when the first diaphragm is retracted from the position, a controller performs a process of adjusting the incident angle.