Substrate Liquid Film Uniformity via Multi-Speed Diffusion
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Solution Overview
Problem
The existing methods for applying photosensitive films onto substrates during semiconductor manufacturing result in non-uniform thickness across the substrate, with the film being thinner towards the periphery compared to the center, leading to inefficiencies in the application process.
Innovation Solution
A method and apparatus that involve a multi-step liquid supplying and diffusing process, including primary and secondary diffusion steps with varying rotational speeds, and a reflow step to ensure uniform thickness of the photosensitive film across the substrate, with the substrate being rotated at different speeds to distribute the treatment liquid effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is rotated at a constant speed to apply photosensitive liquid, then the application process is simple, but the film thickness becomes non-uniform (thinner at periphery)
Solution Approach 1:
The diffusion process is segmented into multiple stages with different rotational speeds. The first diffusion step uses a first rotational speed, followed by a second diffusion step using a second rotational speed that is higher than the first. This segmentation allows different regions of the substrate to receive appropriate amounts of liquid for uniform thickness.
Solution Approach 2:
The rotational speed of the substrate is dynamically adjusted during the diffusion process. The system transitions from a first rotational speed during the first diffusion step to a second rotational speed during the second diffusion step. This dynamic adjustment optimizes liquid distribution to achieve uniform film thickness across the substrate.
2Quantity of substance
If the substrate rotation speed is increased to supply liquid to peripheral areas, then liquid distribution improves, but liquid may be excessively diffused or thickness becomes non-uniform
Solution Approach 1:
The diffusion process employs periodic action with alternating rotational speeds. The substrate rotates at a first rotational speed during the first diffusion step, then at a second rotational speed during the second diffusion step. This periodic variation in rotation speed ensures adequate liquid supply to peripheral areas while maintaining overall thickness uniformity.
3Manufacturing precision
If a single diffusion step is used, then the process is fast, but the liquid does not distribute uniformly across the substrate area
Solution Approach 1:
The system uses dynamic rotational speed adjustment with a first rotational speed for the first diffusion step and a second rotational speed for the second diffusion step. This dynamic approach achieves uniform liquid distribution across the substrate while optimizing the overall process time.
Solution Approach 2:
The rotational speed parameter is changed between diffusion steps. The first rotational speed is used initially, then changed to a second rotational speed that is higher. This parameter change enables effective liquid distribution across different substrate regions, achieving uniformity without excessive process time.
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 ensures a uniform thickness of the photosensitive film across the substrate, improving the application process by adequately supplying the liquid to the peripheral areas and maintaining the film's thickness, thereby enhancing the overall manufacturing efficiency.
Implementation Method 1
The photosensitive liquid supplied to the center of the substrate is diffused to the entire area of the substrate by a centrifugal force
Data Source
AI summary
Disclosed are a method and an apparatus for applying a liquid onto a substrate. The method for treating a substrate, the method includes: a liquid supplying step of supplying a treatment liquid for forming a liquid film on the substrate while rotating the substrate; and a liquid diffusing step of diffusing the treatment liquid discharged to the substrate by rotating the substrate, after the liquid supplying step. The liquid diffusing step includes: a primary diffusion step of rotating the substrate at a first diffusion speed; and a secondary diffusion step of rotating the substrate at a second diffusion speed, after the primary diffusion step. The second diffusion speed is higher than the first diffusion speed. Accordingly, the treatment liquid can be applied to the substrate again by performing the secondary diffusion step, making it possible to adjust the thickness of a photosensitive film.