Flexible Transfer Substrate for Secondary Imaging Lithography
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Solution Overview
Problem
Current lithography technologies face challenges such as high costs, resolution limitations, contamination, and pattern defects due to hard contact and dust sensitivity in high-resolution imaging processes, particularly in optical lithography and surface plasmon lithography.
Innovation Solution
A secondary imaging optical lithography method using a flexible transparent transfer substrate with a photosensitive layer for pattern transfer, which avoids hard contact between the mask and substrate, reduces contamination, and minimizes dust effects by employing a two-step imaging process with distinct light sources and a clean environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical lithography uses high numerical aperture projection objectives and shorter wavelengths to achieve high resolution, then imaging resolution is improved, but device cost increases significantly
Solution Approach 1:
The patent segments the lithography process into two distinct imaging steps: first imaging the mask pattern onto a flexible transparent transfer substrate, then transferring that pattern to the photoresist-coated device substrate. This segmentation allows each imaging step to operate at lower complexity while achieving cumulative high resolution through the secondary imaging process
Solution Approach 2:
The flexible transparent transfer substrate serves as an intermediary carrier between the mask and the device substrate. It receives the first imaging pattern and transfers it to the final substrate, enabling resolution enhancement without requiring the primary imaging system to achieve the full resolution in a single step
2Device complexity
If proximity contact lithography uses contact between mask and substrate to achieve pattern transfer, then manufacturing cost is reduced, but pattern contamination and damage increase
Solution Approach 1:
The patent uses a flexible transparent transfer substrate as a thin film intermediary that contacts the mask during first imaging, then transfers the pattern to the device substrate. This flexible film approach reduces direct hard contact between the expensive mask and the device substrate, minimizing contamination and damage while maintaining cost-effectiveness
Solution Approach 2:
The first imaging process creates a copy of the mask pattern on the flexible transparent transfer substrate. This intermediate copy is then transferred to the device substrate in the second imaging step, protecting the original mask from direct contact with the device substrate and reducing contamination risks
3Manufacturing precision
If hard contact between mask and substrate is used in lithography, then pattern transfer is achieved, but mask service life decreases due to friction and damage
Solution Approach 1:
The flexible transparent transfer substrate acts as a mediator between the mask and the device substrate. During first imaging, it contacts the mask to receive the pattern, then during second imaging, it contacts the device substrate to transfer the pattern. This intermediary role protects the mask from direct friction and damage with the device substrate, extending mask service life
Solution Approach 2:
The flexible nature of the transfer substrate allows it to conform to contact surfaces while being replaceable and less valuable than the mask. Its flexibility enables effective pattern transfer through contact without the same durability requirements as the mask, reducing wear on the expensive mask component
4Device complexity
If nano-imprint technology uses physical extrusion for pattern transfer, then manufacturing cost is reduced, but compatibility with conventional masks and photoresist processes is lost
Solution Approach 1:
The patent replaces the mechanical physical extrusion process of nano-imprint technology with optical imaging processes. Two sequential optical imaging steps are used instead of mechanical pressing, maintaining compatibility with conventional photoresist materials and lithography processes while achieving similar cost benefits
Solution Approach 2:
The flexible transparent transfer substrate serves multiple functions: it acts as a photoresist layer for first imaging, as a transparent medium for light transmission, and as a flexible carrier for pattern transfer. This multi-functionality enables compatibility with conventional optical lithography processes while achieving the cost benefits of simplified hardware
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 high-resolution and super-resolution imaging with increased mask lifetime, uniform pattern distribution, and reduced defects by ensuring close and even contact between the flexible substrate and the mask or device substrate, while maintaining a clean environment to prevent dust contamination.
Implementation Method 1
irradiating the photosensitive layer of the flexible transparent transfer substrate through the lithography mask plate with a first light source, so as to transfer a pattern of the lithography mask plate to the photosensitive layer of the flexible transparent transfer substrate
Implementation Method 2
irradiating the device substrate through the flexible transparent transfer substrate with a second light source, so as to transfer a pattern of the photosensitive layer of the flexible transparent transfer substrate to the photoresist of the device substrate by exposing the photoresist
Data Source
AI summary
The present disclosure provides a secondary imaging optical lithography method and apparatus. The method includes: contacting a lithography mask plate with a flexible transparent transfer substrate closely, the flexible transparent transfer substrate comprising a first near-field imaging structure having a photosensitive layer; irradiating the photosensitive layer through the lithography mask plate with a first light source, so as to transfer a pattern of the lithography mask plate to the photosensitive layer; coating a device substrate for fabricating devices with a photoresist; contacting the flexible transparent transfer substrate with the photoresist-coated device substrate closely; irradiating the device substrate through the flexible transparent transfer substrate with a second light source, so as to transfer a pattern of the photosensitive layer to the photoresist of the device substrate; and developing the device substrate comprising an exposed photoresist, so as to obtain a device pattern conforming to the pattern of the lithography mask plate.