Illumination Optical Module Uniform Numerical Aperture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical systems used in lithography processes face challenges in detecting fine-sized defects due to low resolution, which can lead to performance degradation. Increasing the numerical aperture (NA) to improve resolution results in larger equipment and decreased production efficiency.
Innovation Solution
An illuminating optical module is designed to maintain a consistent numerical aperture (NA) across the entire field of view (FOV) by using an aperture stop positioned at the focal distance of two lenses within the module. This configuration ensures that the beam irradiated to the sample has the same NA in all parts of the FOV, improving resolution and signal sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the numerical aperture (NA) is increased to improve resolution, then the resolution is improved, but the equipment size increases and production efficiency decreases
Solution Approach 1:
The patent applies local quality by positioning the aperture stop at a specific location (focal distance of two lenses) to create a localized control point for NA adjustment. This allows precise control of beam characteristics at the sample plane without requiring the entire optical system to be scaled up, thereby maintaining high resolution while avoiding proportional increases in equipment size that would reduce productivity.
Solution Approach 2:
The patent changes the parameter of numerical aperture (NA) distribution across the field of view by repositioning the aperture stop. Instead of using a uniformly high NA throughout the system (which would require large equipment), the invention adjusts NA locally at the sample plane through precise aperture stop positioning, achieving high resolution without the need to scale up the entire optical system.
2Measurement precision
If the numerical aperture (NA) is increased to improve resolution, then the resolution is improved, but the equipment size increases
Solution Approach 1:
The aperture stop is positioned at a specific focal distance to create a localized control point for NA adjustment. This allows high NA to be achieved only where needed (at the sample plane) rather than requiring the entire optical path to accommodate high NA, thereby preventing proportional increases in equipment size.
Solution Approach 2:
The invention changes the spatial distribution of the NA parameter across the optical system. By repositioning the aperture stop, the system achieves high NA locally at the sample plane while maintaining smaller overall equipment dimensions, as the high NA condition is not propagated throughout the entire optical path.
3Measurement precision
If an extremely short wavelength is used to improve resolution, then the resolution is improved, but it causes limitations in the configuration of the optical system and may cause damage to the inspection region
Solution Approach 1:
Instead of changing the wavelength parameter to achieve high resolution, the invention changes the NA distribution parameter by repositioning the aperture stop. This allows high resolution to be achieved through optical geometry optimization rather than using extremely short wavelengths, thereby avoiding the harmful effects of high-energy radiation on the inspection region.
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 solution enhances the resolution and uniformity of signals acquired from the sample by ensuring that the beam has the same NA across the entire FOV, thereby reducing signal distortion due to surrounding structures without increasing the size of the optical system.
Implementation Method 1
an aperture stop that in a path of the beam and between the second lens and the third lens, the aperture stop configured to adjust a size of a numerical aperture (NA)
Implementation Method 2
a first lens configured to receive a beam from a light source module
Implementation Method 3
a second lens configured to receive the beam from the first lens
Implementation Method 4
a field stop between the first lens and the second lens and configured to adjust the area of the beam transmitted to the second lens
Implementation Method 5
a third lens configured to transmit the beam transmitted from the second lens to a sample
Data Source
AI summary
An illuminating optical module according to an embodiment transmits a beam irradiated from a light source module to a sample, and may include: a first lens that receives a beam from the light source module; a second lens that receives the beam from the first lens; a field stop that is disposed between the first lens and the second lens and adjusts the amount of beam transmitted to the second lens; a third lens that transmits the beam transmitted from the second lens to the sample; and an aperture stop that is disposed on a path of the beam passing between the second lens and the third lens and adjusts a size of numerical aperture (NA), wherein the aperture stop may make the beam transmitted to the sample have the same NA in all parts of a field of view (FOV).