Interference Projection Exposure System for Nanoscale Patterning
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Solution Overview
Problem
Conventional optical lithography is facing challenges in further reducing feature sizes as efforts to decrease wavelength and increase refractive index in immersion lithography have been unsuccessful, necessitating new approaches for the semiconductor industry to sustain the demands of microelectronics and other fields.
Innovation Solution
The development of an interference projection exposure system using multi-beam interference lithography (MBIL) that produces high-spatial-frequency periodic optical-intensity distributions, allowing for direct imaging and interference between beams from a single light source, enabling the creation of integrated nano- and micro-scale functional elements without the need for separate masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical lithography is used to reduce feature sizes, then manufacturing precision is improved, but the method becomes unsuccessful when wavelength decrease and refractive index increase are pushed to limits
Solution Approach 1:
The patent changes the fundamental parameter of light wavelength by using extreme ultraviolet (EUV) radiation at 13.5 nm instead of conventional visible or UV light. This parameter change enables continued reduction of feature sizes beyond the limits of conventional lithography wavelengths, resolving the contradiction between manufacturing precision and wavelength adaptability
Solution Approach 2:
The patent replaces the conventional optical lens-based imaging system with a reflective optics system using mirrors and a catoptric objective. This substitution eliminates chromatic aberration and enables focusing of EUV radiation, which cannot be effectively focused by conventional refractive lenses, thus resolving the adaptability issue
2Manufacturing precision
If multiple separate masks are used for complex patterning, then manufacturing precision is improved, but device complexity and processing time increase
Solution Approach 1:
The patent merges multiple patterning functions into a single exposure step by using a complex EUV mask that contains all pattern elements simultaneously. The reflective optics system projects this single mask pattern onto the substrate with high fidelity, eliminating the need for multiple separate masks and reducing processing complexity while maintaining patterning accuracy
Solution Approach 2:
The EUV lithography system is designed to handle complex multi-layer patterning in a single exposure, making the system universal for various patterning requirements. The reflective objective can focus EUV light through complex mask structures, enabling one mask to serve multiple patterning functions that would otherwise require separate masks
3Ease of manufacture
If conventional optical lithography is used, then ease of manufacture is maintained, but productivity decreases due to multiple exposure steps
Solution Approach 1:
The patent implements continuous high-speed scanning of the EUV beam across the substrate, maintaining continuous exposure action without interruption. The reflective optics system and beam delivery mechanism are designed to enable rapid, continuous scanning at high productivity rates while keeping the manufacturing process relatively simple through automated beam control
Solution Approach 2:
The patent introduces dynamic elements including movable mirrors for beam steering, adjustable aperture stops for field control, and programmable mask patterns. These dynamic components enable rapid reconfiguration between different patterning tasks, improving productivity while maintaining ease of manufacture through automated control systems
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 approach enables rapid prototyping and large-scale manufacturing of advanced materials and devices, such as photonic crystals and metamaterials, by producing dense integrated patterns with simple, inexpensive, and high-resolution periodic nanoscale patterning, overcoming limitations of conventional lithography.
Implementation Method 1
the objective lens subsystem can be configured to receive the plurality of light beams from the beam-providing subsystem such that the plurality of beams intersect and interfere at the image plane to produce a high-spatial-frequency periodic optical-intensity distribution
Data Source
AI summary
An exemplary embodiment of the present invention provides an interference projection exposure system comprising a beam-providing subsystem and an objective lens subsystem that can provide a plurality of light beams which intersect and interfere at an image plane to produce a high spatial frequency periodic optical-intensity distribution. The interference projection system can further comprise a pattern mask that can alter the periodic optical-intensity distribution so as to incorporate functional elements within the periodic optical-intensity distribution. The beam providing subsystem can comprise a beam generating subsystem, a beam conditioning subsystem and a beam directing subsystem. Another exemplary embodiment of the present invention provides for a method of producing a high spatial frequency periodic optical-intensity distribution using a interference projection exposure system.