Substrate Treating Apparatus Edge Coating Uniformity
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Solution Overview
Problem
High viscosity photoresist used in coating film formation on substrates leads to non-uniform film thickness and defects like tearing and poor coating, especially near the edge regions of the substrate.
Innovation Solution
A substrate treating method and apparatus that involves forming a liquid film by supplying a treatment liquid to a rotating substrate and spraying a wetting medium in the form of fine particles or mist towards the edge region of the substrate to enhance diffusion and prevent evaporation of the solvent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high viscosity photoresist is used to form coating film, then the coating film can be formed on substrate, but the uniformity of film thickness deteriorates and defects like tearing occur
Solution Approach 1:
A wetting medium is introduced as an intermediary substance between the high viscosity photoresist and the substrate. This wetting medium reduces the surface tension of the photoresist, enabling it to spread uniformly across the substrate surface even at high viscosity levels, thereby preventing tearing and poor coating defects while maintaining manufacturing precision
Solution Approach 2:
The patent changes the physical-chemical parameters of the photoresist by adjusting its temperature and adding solvents to modify viscosity and surface tension characteristics. These parameter changes enable the photoresist to achieve uniform spreading on the substrate without causing tearing or coating defects
2Productivity
If photoresist is supplied to central region and spread by centrifugal force, then coating film can be formed, but edge region coating uniformity deteriorates
Solution Approach 1:
The patent applies local quality by supplying photoresist to the central region for efficient coating formation while simultaneously applying wetting medium to the edge region to improve local spreading characteristics. This localized approach maintains productivity while correcting edge region uniformity issues
Solution Approach 2:
The wetting medium acts as an intermediary that is specifically applied to the edge region to facilitate photoresist spreading in areas where centrifugal force alone is insufficient, thereby improving edge region coating uniformity without compromising overall coating efficiency
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
The method improves the uniformity of the liquid film on the substrate, minimizes defects such as tearing and poor coating, and ensures efficient treatment of the substrate.
Implementation Method 1
the photoresist PR supplied to the central region of the substrate W is spread toward an edge region of the substrate W by a centrifugal force generated by the rotation of the substrate W
Implementation Method 2
a wetting medium is sprayed in a form of fine particles to the substrate to help diffusion of the liquid film
Data Source
AI summary
The inventive concept provides a method for treating a substrate. In the substrate treating method, a liquid film is formed by supplying a treatment liquid to the rotating substrate, and a wetting medium is sprayed in a form of fine particles to the substrate to help diffusion of the liquid film.