Illumination Optical System with Input Lens for Exposure Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current illumination optical systems in exposure apparatuses face challenges in achieving high resolution due to wavelength range limitations and chromatic aberration, particularly with the use of projection lenses, which affect the image quality projected onto substrates.
Innovation Solution
The proposed illumination optical system includes an integrator optical system, an input lens, a bandpass filter, and a condenser lens, where the bandpass filter is strategically positioned between the input lens and the integrator optical system, and the aperture is larger than the irradiation region, effectively minimizing the influence of incident-angle dependence and enhancing filter characteristics to improve exposure resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a bandpass filter is disposed closer to the light source relative to the integrator lens, then the resolution reduction due to chromatic aberration is suppressed, but the incident-angle dependence of the bandpass filter increases, degrading filter characteristics
Solution Approach 1:
An input lens is introduced as an intermediary optical element between the light source and the bandpass filter. This input lens conditions the incident light to reduce the incident angle dependence on the bandpass filter, allowing the filter to maintain its characteristics while still achieving chromatic aberration correction. The input lens acts as a mediator that transforms the light properties before it reaches the filter.
Solution Approach 2:
The patent changes the spatial arrangement by adding the input lens in the optical path, effectively adding another dimensional element to the system configuration. This additional optical element in the light path allows simultaneous achievement of both filter characteristic maintenance and chromatic aberration suppression by controlling light incidence from a different spatial perspective.
2Productivity
If the aperture size is reduced to match the irradiation region size, then the light path efficiency improves, but the incident-angle dependence of the bandpass filter increases
Solution Approach 1:
The input lens serves as an intermediary that decouples the aperture size from the incident angle dependence. By conditioning the light through the input lens before it reaches the bandpass filter, the system can use a larger aperture for better light efficiency while the input lens ensures that the filter still receives light at acceptable angles to maintain its filtering characteristics and exposure resolution.
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 configuration significantly reduces chromatic aberration and improves exposure resolution by ensuring that only the desired wavelength band is used for exposure, resulting in higher image quality and precision.
Implementation Method 1
a bandpass filter, which transmits only light in a specific wavelength range
Implementation Method 2
uniformizes an illuminance distribution of light with which a target object is to be irradiated
Implementation Method 3
an input lens, which is disposed on a light incident side of the integrator optical system
Implementation Method 4
a condenser lens, which irradiates a target object with light emitted from the aperture
Data Source
AI summary
An illumination optical system, which irradiates a target object with light from a light source unit includes: an integrator optical system that is disposed on an optical path of the light emitted from the light source unit and uniformizes an illuminance distribution of the light with which the target object is to be irradiated; an input lens that is disposed on a light incident side of the integrator optical system; a bandpass filter that is disposed between the input lens and the integrator optical system; an aperture that is disposed on a light emission side of the integrator optical system; and a condenser lens that irradiates the target object with light emitted from the aperture, the aperture having a size larger than a size of an irradiation region of the light with which the target object is to be irradiated.