DOE Lens Array Beam Splitter for Lithography Alignment
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Solution Overview
Problem
Existing beam splitting apparatuses for lithography operations face challenges in alignment and complexity due to the use of multiple optical elements, leading to increased mirror counts as the number of beams increases, making it difficult to efficiently modify a single beam into a bundle of beams.
Innovation Solution
An optical device comprising a first lens array with diffractive optical element (DOE) lenses and a second lens array with corresponding DOE lenses, where the lenses are arranged in a two-dimensional matrix on parallel planes with a controlled interval between them, allowing for the splitting and modification of a single beam into multiple parallel beams, and a piezoelectric device adjusts the divergent angle of these beams by controlling the interval between the lens arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a beam splitting apparatus uses a plurality of optical elements to modify a single beam into multiple beams, then the beam splitting function is achieved, but the alignment difficulty and structural complexity increase
Solution Approach 1:
The patent divides the optical system into two separate lens arrays, each containing multiple DOE lenses arranged in a matrix. The first lens array splits the incident beam into multiple intermediate beams, and the second lens array further processes these into the final multi-beam output. This segmentation allows each array to be optimized independently while achieving the overall beam splitting function with reduced complexity compared to traditional multi-element optical systems.
Solution Approach 2:
The patent transitions from conventional one-dimensional or sequential beam splitting to a two-dimensional matrix arrangement of DOE lenses. Both lens arrays are configured with multiple lenses arranged in rows and columns, enabling simultaneous beam splitting in multiple directions and producing a two-dimensional array of output beams. This dimensional approach efficiently generates multiple beams from a single incident beam with fewer optical elements.
2Adaptability or versatility
If the number of beams is increased in a beam splitting apparatus, then the beam splitting capability is improved, but the number of mirrors and alignment difficulty increase
Solution Approach 1:
The patent segments the beam splitting function across two lens arrays with multiple DOE lenses each. When more output beams are needed, additional DOE lenses can be added to the matrix arrangement in either or both arrays. Each DOE lens independently processes a portion of the incident beam, allowing the system to scale to high beam counts without requiring proportionally more complex alignment of individual optical elements.
Solution Approach 2:
The patent replaces traditional mechanical mirror-based beam splitting with diffractive optical element (DOE) lenses that use optical diffraction and phase modulation. Instead of physically positioning and aligning multiple mirrors to redirect beams, the DOE lenses use micro-structured surface patterns to diffract and focus light into multiple beams. This substitution eliminates the need for precise mechanical alignment of mirrors while maintaining the ability to generate multiple beams.
3Ease of operation
If the interval between lens arrays is adjusted to control beam divergence, then beam angle control is improved, but the device complexity increases
Solution Approach 1:
The patent introduces a piezoelectric device between the first and second lens arrays that can dynamically adjust the interval (distance) between the two arrays. By applying voltage to the piezoelectric actuator, the spacing between lens arrays is precisely controlled, which in turn adjusts the divergence angle of the output beams. This dynamic adjustment mechanism allows real-time control of beam characteristics without mechanical reconfiguration of the entire optical system.
Solution Approach 2:
The patent controls beam divergence by changing the physical parameter of the interval distance between the two lens arrays. The piezoelectric device enables precise modification of this spacing parameter, which directly affects the optical path and the resulting beam divergence angle. By varying this single geometric parameter through electrical actuation, the system achieves beam angle control without adding complex mechanical adjustment mechanisms.
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 simplifies the beam splitting process, reduces the complexity of the apparatus, and allows for precise control over the angle and intensity of the output beams, achieving efficient beam modification with fewer optical elements while maintaining high beam intensity and low spread.
Implementation Method 1
a first lens array including a plurality of first diffractive optical element (DOE) lenses that are two-dimensionally arranged on a first plane, and that split a first parallel beam into a plurality of second beams by condensing the first parallel beam
Implementation Method 2
a piezoelectric device that is disposed between the first lens array and the second lens array. A divergent angle of the third beams may be adjusted by controlling a voltage applied to the piezoelectric device to control an interval between the first lens array and the second lens array
Data Source
AI summary
An optical device for splitting a single beam to a plurality of beams and an exposure apparatus including the optical device are disclosed. The optical device includes a first DOE lens array including a plurality of first diffractive optical element (DOE) lenses that are two-dimensionally arranged on a first plane and a second lens array including a plurality of second DOE lenses arranged on a second plane parallel to the first plane so as to respectively correspond to the plurality of first DOE lenses. The first DOE lens array splits a first parallel beam into a plurality of second beams by condensing the first parallel beam and the second DOE lens array modifies the plurality of second beams into a plurality of third beams.