Flat-Angle Correction Light Irradiation for Microlithography Lens Thermal Inhomogeneity
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Solution Overview
Problem
In optical configurations, such as microlithography lenses, non-rotationally symmetrical illumination can lead to inhomogeneous irradiation and heating of optical elements, causing distortions and imaging errors due to inhomogeneous heating.
Innovation Solution
A device using a multi-mirror array with individually controllable mirror elements for lateral irradiation with correction light, allowing for locally and temporally variable correction of thermal inhomogeneities by adjusting the angle of incidence and power distribution, minimizing beam divergence and shadowing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If correction light is irradiated laterally at a flat angle onto the optical element, then thermal inhomogeneities can be corrected effectively even at short distances from adjacent parts, but the device complexity increases due to the need for precise mirror arrangement and angle control
Solution Approach 1:
The optical element surface is divided into multiple regions, each illuminated by a separate laser beam with independently controllable parameters (angle, power, wavelength). This segmentation allows targeted correction of thermal inhomogeneities in specific regions without affecting other areas, enabling precise local control while maintaining overall system manageability
Solution Approach 2:
The correction device uses multiple laser beams that can be adjusted in angle, power, and wavelength to handle various types of thermal inhomogeneities and optical element geometries. The same system can correct different regions with different characteristics using a unified approach, reducing the need for multiple specialized devices
2Adaptability or versatility
If the correction light device is arranged laterally at a flat angle, then the optical arrangement is not impaired and interchangeability is improved, but the area required for device placement increases
Solution Approach 1:
Instead of placing the correction light device along the optical axis (one dimension), the invention positions it laterally at a flat angle, utilizing a different spatial dimension. This lateral arrangement at angles between 80-90 degrees allows the device to be placed in the peripheral region without interfering with the main optical path, improving interchangeability while requiring minimal additional space
3Adaptability or versatility
If non-rotationally symmetrical illumination is used in microlithography, then imaging flexibility is improved, but inhomogeneous heating of optical elements occurs causing imaging errors
Solution Approach 1:
The correction laser beams are applied in advance to counteract the thermal inhomogeneities caused by non-rotationally symmetrical illumination. By pre-heating or cooling specific regions of the optical element before the main exposure, the system compensates for anticipated thermal distortions, maintaining imaging accuracy while preserving the flexibility of asymmetric illumination patterns
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
Enables effective correction of thermal inhomogeneities at short distances from adjacent parts without impairing the optical arrangement, allowing for easy interchangeability and maintaining high uniformity of illumination, thus reducing imaging errors.
Implementation Method 1
The term correction light in this regard includes any electromagnetic radiation, but especially infrared light with a wavelength greater than or equal to 4 μm
Implementation Method 2
non-rotationally symmetrical illumination or a slit-shaped image field can lead to inhomogeneous irradiation of optical elements, which in turn can lead to inhomogeneous heating of the corresponding optical element
Implementation Method 3
the irradiation of an optical element of an optical arrangement with correction light proceeds via at least one mirror arrangement, which deflects the correction light from a correction light source towards the optical element
Data Source
AI summary
The disclosure relates to a correction light device for the irradiation of optical elements of an optical arrangement, in particular a lens, such a microlithography lens having a correction light, which include at least one correction light source and at least one mirror arrangement that deflects the light from the correction light source in the beam path to the optical element such that at least part of at least one surface of at least one optical element of the optical arrangement are irradiated in a locally and/or temporally variable fashion. The correction light strikes the surface of the optical element at a flat angle such that the obtuse angle between the optical axis of the optical arrangement at the location of the optical element and the correction light beam is less than or equal to 105°.