Phase-Mask Nano-Patterning With Angle-Resolved 3D Channel Control
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Solution Overview
Problem
Conventional methods for fabricating 3D nano-structures, such as laser interference lithography and proximity-field nano-patterning (PnP), face challenges including low efficiency, high costs, and limited reproducibility and size applicability, and are restricted to forming specific symmetrical structures like body-centered-cubic or hexagonal channel structures.
Innovation Solution
A method involving a PnP process using a phase mask with an uneven lattice structure and adjusting the light-exposure angle to form nano-structures, allowing for the creation of nano-structures with channels arranged in a rectangular shape by optimizing the incidence angle of light on the photoresist film, which is not achievable with conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser interference lithography is used to fabricate 3D nano-structures, then periodic interference patterns can be formed, but the optical system becomes complicated and costs increase
Solution Approach 1:
The patent extracts the essential function of laser interference lithography (forming periodic interference patterns) and separates it from the complicated optical system. By using a phase mask to generate the interference pattern directly, the complex optical components (lenses, mirrors, beam splitters) are removed, retaining only the core functionality.
Solution Approach 2:
The patent uses a phase mask as a physical template that copies the desired periodic pattern directly onto the photoresist film. Instead of using complex optical systems to project patterns, the phase mask serves as a reusable copy mechanism that simplifies the fabrication process while maintaining pattern accuracy.
2Manufacturing precision
If conventional PnP method with vertical light exposure is used, then symmetrical structures (BCC, BCT) can be formed, but the applicable structure types are limited
Solution Approach 1:
The patent introduces asymmetry by tilting the photoresist film at a specific angle (e.g., 54.7°) relative to the vertically incident laser beam. This breaks the symmetry of the conventional vertical exposure method, enabling the formation of non-symmetrical structures such as rectangular channel arrangements while maintaining manufacturing precision through controlled angular positioning.
Solution Approach 2:
The patent makes the exposure geometry dynamic by allowing adjustment of the photoresist film orientation angle. This dynamic positioning capability enables switching between different structure types (symmetrical and non-symmetrical) by simply changing the film angle, thereby increasing versatility without complicating the phase mask design.
3Adaptability or versatility
If LBL deposition method is used to fabricate 3D nano-structures, then various shapes can be formed, but the process efficiency is low and costs are high
Solution Approach 1:
The patent performs preliminary action by pre-forming the 3D nano-structure pattern directly in a single exposure step using the tilted photoresist film method. This eliminates the need for multiple sequential deposition layers, achieving both shape variety and high productivity by establishing the complete structure geometry in one fabrication pass.
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 the fabrication of nano-structures with varied channel arrangements, such as rectangular shapes, improving process suitability and device performance, and allows for the formation of structures not possible with traditional PnP methods, enhancing the versatility and efficiency of nano-device manufacturing.
Implementation Method 1
The laser beam is diffracted and divided into a plurality of laser beams when passing through the lattice structure of the phase mask. The diffraction of the laser beam may be determined or varies depending on a wavelength of the laser beam, a refractivity of the phase mask and the photoresist film, a depth of the lattice structure, a period of the lattice structure, or the like.
Implementation Method 2
The laser beams interfere with one another in the photoresist film to form a 3D periodic interference pattern
Data Source
AI summary
A method for fabricating a nano-structure includes: providing a phase mask having an uneven lattice structure to contact a photoresist film; exposing the photoresist film to a light through the phase mask such that the light is obliquely incident on a surface of the photoresist film; and developing the photoresist film to form a nano-structure.