Substrate Developer Film Uniformity via Dynamic Rotation Speed
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Solution Overview
Problem
Existing substrate processing methods struggle to maintain uniformity of developer film thickness and concentration across the substrate surface, leading to variations in development progress.
Innovation Solution
A method involving a substrate processing apparatus with a nozzle that supplies a developer at varying rotation speeds and distances, forming a liquid film, then adjusting the rotation speed to ensure uniform distribution and freshness of the developer, optimizing the film thickness and concentration by controlling the nozzle's movement and distance from the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the substrate is rotated at a constant high speed during developer supply, then the developer can be supplied efficiently, but the development progress amount varies according to position on the substrate
Solution Approach 1:
The substrate rotation speed is dynamically changed during the developer supply process. The rotation speed is reduced after developer supply is completed in each radial direction, allowing the developer to spread uniformly by centrifugal force before the substrate rotates to the next position. This dynamic speed adjustment resolves the contradiction between supply efficiency and development uniformity.
2Productivity
If the nozzle moves continuously while supplying developer, then the liquid film can be formed efficiently, but the developer concentration becomes non-uniform across the substrate
Solution Approach 1:
The nozzle movement and developer supply are performed in periodic cycles corresponding to substrate rotation segments. The nozzle supplies developer to a specific radial position, then stops moving while the substrate rotates to allow uniform distribution. This periodic action pattern ensures both efficient film formation and uniform developer concentration.
3Manufacturing precision
If the substrate rotation speed is reduced after developer supply, then the developer spreads more uniformly, but the overall processing time increases
Solution Approach 1:
The substrate rotation speed is reduced only partially and temporarily after each developer supply cycle, just enough time for the developer to spread uniformly by centrifugal force. The rotation then resumes at normal speed for the next supply position. This partial reduction minimizes time loss while achieving sufficient uniformity.
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 enhances the uniformity of the development progress speed both during and after film formation, effectively suppressing variations in development across the substrate surface.
Implementation Method 1
rotating the substrate at a second rotation speed which is slower than the first rotation speed after the liquid film is formed on the surface of the substrate... by reducing the rotation speed of the substrate from the first rotation speed to the second rotation speed, the developer approaches the rotation center side of the substrate, and by increasing the rotation speed of the substrate from the second rotation speed to the third rotation speed, the developer spreads on the outer peripheral side of the substrate
Data Source
AI summary
A substrate processing method includes steps of: supplying a developer onto a substrate surface from a discharge port while the substrate is rotated at a first rotation speed and a liquid contact surface faces the surface, and moving the nozzle while the liquid contact surface contacts with the developer so that a liquid film of the developer is formed on the surface; rotating the substrate at a second rotation speed slower than the first rotation speed, after the liquid film is formed, in a state where supply of the developer is stopped; rotating the substrate at a third rotation speed faster than the first rotation speed, after the substrate is rotated at the second rotation speed; and reducing rotation speed of the substrate to the second rotation speed or less, after the substrate is rotated at the third rotation speed, so that the liquid film is held on the surface.