Interference Lithography Device with Adjustable Beam Path
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Solution Overview
Problem
Conventional laser interference lithography systems face limitations in producing large-area, uniform periodic structures due to non-uniform beam distribution and fixed optical configurations, which restrict their ability to achieve long-period gratings over extended sample areas, requiring laborious reconfiguration and inefficient energy utilization.
Innovation Solution
A compact interference lithography device with adjustable mirror angles and a flexible beam path configuration, allowing for the formation of interference patterns over a large area (over 4 inches) with adjustable grating periods (200-2000 nm) without the need for optical path reconfiguration, using a beam splitter, expanders, and rotatable reflectors to ensure uniform illumination and energy distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If Lloyd's mirror architecture is used to achieve two-beam interference, then the system is simple and easy to set up, but it cannot produce large-area and uniform periodic structure
Solution Approach 1:
The patent divides the single laser beam into two separate beams using a beam splitter, then independently expands each beam using separate beam expanders. This segmentation allows each beam to be optimized for uniform illumination across the sample area, resolving the contradiction between simple setup and large-area uniform exposure capability
Solution Approach 2:
The patent transitions from the traditional Lloyd's mirror two-dimensional arrangement to a three-dimensional optical path configuration where two independently expanded beams intersect at adjustable angles. This dimensional change enables large-area coverage while maintaining uniform intensity distribution across the exposure field
2Ease of operation
If Lloyd's mirror architecture is used, then the system is simple, but the two beams are not evenly distributed resulting in non-uniform irradiation
Solution Approach 1:
By segmenting the optical path into two independent beam channels with separate expanders, each beam can be independently optimized for uniform intensity distribution. The beams are then combined to create a uniformly illuminated interference pattern across the entire sample area
Solution Approach 2:
The patent applies different optical components (separate beam expanders with adjustable lenses) to each beam path to locally optimize the intensity distribution. This allows each beam to be tailored for uniform illumination before interference, ensuring even energy distribution across the exposure area
3Manufacturing precision
If two independent light beams are used with beam splitter to improve uniformity and extend grating period, then the illumination uniformity and grating period are improved, but the optical configuration becomes fixed requiring laborious reconfiguration for varying grating periods
Solution Approach 1:
The patent introduces adjustable parameters including beam expander magnification, beam intersection angle, and sample position that can be dynamically changed to produce different grating periods. This dynamic adjustability eliminates the need for laborious optical path reconfiguration while maintaining uniform grating structure quality
Solution Approach 2:
The patent enables grating period variation through parameter changes in the optical configuration, specifically by adjusting beam expansion ratios, intersection angles, and sample-to-beam-distance. These parameter adjustments allow flexible grating period control without physical reconfiguration of the optical path
4Adaptability or versatility
If large optical table is used to guarantee degrees of freedom for optical path realignment, then the optical path alignment flexibility is improved, but the system size increases
Solution Approach 1:
The patent designs a compact optical configuration where adjustable parameters (beam expansion, angle, position) provide multiple degrees of freedom for alignment and grating period control within a small footprint. This multi-functional approach replaces the need for large optical tables while maintaining alignment flexibility
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 flexible adjustment of grating periods and exposure areas while maintaining system compactness, achieving uniform and high-intensity interference patterns across large areas, suitable for various applications including semiconductor lasers and light-emitting diodes.
Implementation Method 1
a beam splitter disposed on the base and configured to divide the laser beam into a first beam portion and a second beam portion
Implementation Method 2
a beam expander disposed on the base and in front of the beam splitter to respectively expand a diameter of the first beam portion and a diameter of the second beam portion
Implementation Method 3
a first set of reflectors disposed on the base and between the beam splitter and the beam expander, and having a first reflector and a second reflector respectively reflecting the first beam portion and the second beam portion to the beam expander
Implementation Method 4
two coherent lights to overlap in space to produce periodic interference fringes
Implementation Method 5
When a photosensitive material (such as a photoresist) is placed under the interference fringes, the interference fringes can be transferred to the photoresist layer
Data Source
AI summary
An interference lithography device is provided with a laser source for providing a laser beam; a base thereon having a beam splitter for dividing the laser beam into a first beam portion and a second beam portion, a beam expander, a first set of reflectors, and a second set of reflectors; a set of lower reflectors; and a sample carrying stage for holding a substrate. The first beam portion and the second beam portion are respectively reflected from the second set of reflectors and then respectively reflected by the set of lower reflectors to form an interference pattern on the substrate.