Movable Membrane Optics for High-Throughput 3D Lithography
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Solution Overview
Problem
Existing 3D direct-writing laser lithography methods face challenges with contamination transfer, lens damage, limited working distance, force-induced misalignment, and inefficient photoresist consumption due to the direct contact between the immersion medium and objective lens, especially in high-throughput industrial applications.
Innovation Solution
A device with a movable membrane between the objective lens and the specimen slide, using a thin, flexible film as the immersion medium, allowing for adjustable axial positioning and separation from the lens, minimizing contamination and force transfer while maintaining optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin cover glass is used to separate the objective lens from the photoresist, then the working distance is reduced and manufacturing precision is improved, but the maximum height of structures that can be written is limited
Solution Approach 1:
The patent introduces an axially movable membrane instead of a fixed cover glass. The membrane can be positioned at different distances from the objective lens, allowing the system to adapt between high-precision mode (membrane close to lens) and high-structure-height mode (membrane moved away from lens), thus resolving the contradiction between precision and structure height capability
Solution Approach 2:
The system separates the membrane function from the objective lens assembly. The membrane is independently movable relative to the lens, allowing the optical interface function to be decoupled from the positioning function. This enables the membrane to be optimally positioned for each specific writing task, whether prioritizing precision or structure height
2Stability of the object's composition
If the cover glass is attached directly to the objective lens, then the optical interface is stabilized, but forces in the photoresist cause misalignment and potential damage to existing structures
Solution Approach 1:
The membrane acts as an intermediary element between the objective lens and the photoresist. It provides a stable optical interface for the lens while being in contact with the photoresist, thus mediating the interaction and preventing direct force transmission between the lens and photoresist that would cause misalignment
Solution Approach 2:
The patent extracts the force-transmitting function from the optical interface. By using a membrane holder that attaches to the lens mount rather than attaching the membrane directly to the lens, the system separates the optical stabilization function from the mechanical support function, preventing force-induced misalignment
3Illumination intensity
If the objective lens is in direct contact with the immersion medium, then optical coupling is maximized, but contamination transfer and lens damage occur
Solution Approach 1:
The membrane serves as an intermediary layer between the objective lens and the immersion medium (photoresist). It maintains optical coupling by being transparent to the lithography wavelength while preventing direct contact between the lens and photoresist, thus blocking contamination transfer and chemical damage
Solution Approach 2:
The patent uses a thin, flexible membrane that is optically transparent at the lithography wavelength. This thin film provides sufficient optical transparency to maintain high coupling efficiency while being thin enough to minimize optical path differences and thick enough to provide effective mechanical separation and contamination barrier
4Manufacturing precision
If a fixed distance between the object and cover glass is maintained, then optical quality is preserved, but geometric aberrations occur when writing at different depths
Solution Approach 1:
The membrane is made axially movable rather than fixed, allowing its distance from the objective lens to be dynamically adjusted. This enables the system to maintain optimal optical conditions at different writing depths by repositioning the membrane, thus preserving optical quality across varying writing conditions
Solution Approach 2:
The system changes the positional parameter of the membrane axially to adapt to different writing depths. By adjusting the membrane's axial position, the optical path is optimized for each specific writing depth, maintaining geometric accuracy and minimizing aberrations across the full writing volume
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 high-throughput lithography with reduced photoresist consumption, minimized lens misalignment, and controlled aberrations, facilitating the creation of structures with varying heights and surface topographies without lens contamination or damage.
Implementation Method 1
the membrane has a partial area designed for the penetration of light
Implementation Method 2
an immersion medium, which is inserted at least between the membrane and the specimen slide
Data Source
Figure 1
Figure 2a~2d
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AI summary
The invention relates to an apparatus (10) and a method for optically characterizing or processing an object (60), and an object transport unit (55). The apparatus (10) comprises: - an object carrier (50) for receiving an object (60); - an optical characterization or processing unit (15) comprising at least one device for generating or receiving light (140) and an objective lens (40) for exposing the object (60) by means of the light (140) or for capturing the light (140) from the object (60), wherein the objective lens (40) has an end face (46) facing the object carrier (50), wherein the end face (46) has an edge (47) and wherein the objective lens (40) further sets an optical axis (502); - at least one membrane (100) introduced between the objective lens (40) and the object carrier (50), wherein the membrane (100) has a portion (120) configured for the passage of the light (140), wherein at least the portion (120) of the membrane (100) is movable in the axial direction with respect to the optical axis (502), - at least one membrane holder (80) for holding the at least one membrane (100), and - at least one immersion medium (160) which is at least introduced between the membrane (100) and the object carrier (50), wherein the membrane (100) and the membrane holder (80) are fastened to a point outside of the objective lens, and wherein the membrane (100) is disposed at the membrane holder (80) in such a way that first contact points (81) between the membrane (100) and the membrane holder (80) are on, or outside of, a lateral face (510), which is formed by a geometric extrusion of the edge (47) of the objective lens (40) parallel to the optical axis (502). The apparatus (10), the method and the object transport unit (55) facilitate the optical characterization or processing of an object (60) in a way that meets the particular demands of industrial applications with a high throughput.