Liquid Deposition Photolithography for Complex 3D Structures
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Solution Overview
Problem
Traditional photolithography techniques are inefficient and costly for creating complex, non-flat patterns due to their requirement for flat substrates and time-consuming processes, especially when fabricating complex geometric patterns.
Innovation Solution
A liquid deposition photolithography system that uses a photo-sensitive liquid with mobile monomers, an optical window for mechanical support, and a material delivery subsystem to create customized structures in a liquid environment, allowing for precise layer control and the use of multiple materials, enabling the formation of complex structures like circuits, lenses, and tissue scaffolds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional photolithography techniques are used to create complex geometric patterns, then manufacturing precision can be achieved, but the process becomes time-consuming and expensive
Solution Approach 1:
The patent replaces traditional mechanical photolithography processes with a digital light processing system. An optical engine projects digital images directly onto the photoresist-coated substrate, eliminating the need for physical photomasks and multiple exposure steps. This substitution of mechanical/optical systems with a digital projection system dramatically reduces process time while maintaining manufacturing precision for complex geometric patterns.
Solution Approach 2:
The patent changes the state of the photoresist material from solid to liquid during processing, then back to solid after development. The liquid photoresist allows for more uniform coating and better flow characteristics during the imaging process. Additionally, the system uses specific wavelength UV light (365nm or 405nm) to trigger polymerization, optimizing the chemical transformation parameters to achieve rapid curing while maintaining pattern fidelity.
2Ease of manufacture
If traditional photolithography requires flat substrates, then process simplicity is maintained, but the ability to create non-flat shapes is limited
Solution Approach 1:
The patent introduces a liquid photoresist layer that can dynamically conform to substrates of any shape or topography. Unlike traditional solid photoresists that require flat surfaces for uniform coating, the liquid formulation flows and adapts to complex three-dimensional substrate geometries. This dynamic behavior allows the same simple projection process to work on both flat and non-flat substrates, simultaneously achieving process simplicity and shape versatility.
Solution Approach 2:
The patent changes the physical state of the photoresist to liquid, which fundamentally alters its interaction with the substrate. The liquid state allows the photoresist to wet and conform to complex substrate surfaces, then undergoes UV-induced polymerization to lock in the desired three-dimensional shape. This parameter change from solid to liquid state enables the system to handle diverse substrate geometries without complicating the manufacturing process.
3Manufacturing precision
If multiple treatments of light-sensitive polymer are used to create complex patterns, then pattern complexity is achieved, but material consumption and cost increase
Solution Approach 1:
The patent replaces multiple sequential photolithography treatments with a single digital light projection exposure. The optical engine can project complex multi-layer patterns in one exposure step, eliminating the need for repeated photoresist coating, exposure, and development cycles. This substitution reduces photoresist material consumption significantly while achieving the same pattern complexity through digital image projection.
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 system enables rapid and efficient creation of complex, multi-layer structures with high resolution and minimal material waste, overcoming the limitations of traditional photolithography by allowing non-contact molding and the use of multiple materials, thus simplifying the fabrication of intricate patterns.
Implementation Method 1
The materials can include a photo-sensitive liquid having mobile monomers that can be locally polymerized when exposed to an optical intensity pattern created by the optical pattern generator
Implementation Method 2
The optical window allows the intensity pattern to enter the exposure chamber thereby modifying the properties of the materials within the exposure chamber
Data Source
AI summary
Systems and methods for liquid deposition photolithography are described. In particular, some embodiments relate to systems and methods for using photolithography to control the 2D structure of a thin layer of material (e.g., photopolymer) using various masks, projection optics and materials. In one or more embodiments, this thin layer can be manipulated by micro-fluidic techniques such that it can be formed, patterned and post-processed in a liquid environment, vastly simplifying the creation of multi-layer structures. Multiple layers are rapidly built up to create thick structures of possibly multiple materials that are currently challenging to fabricate by existing methods.