Spin Chuck Air Flow Control for Uniform Resist Film
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Solution Overview
Problem
Conventional spin chucks fail to maintain uniform thickness of resist films on polygonal substrates due to uneven solvent evaporation, leading to increased thickness at corner portions and complexity in loading/unloading processes, which affects the throughput and precision of semiconductor and LCD manufacturing.
Innovation Solution
A liquid processing apparatus with a spin chuck and air flow control members positioned along the periphery of the substrate, excluding corner portions, creates a descending clean air flow to suppress solvent evaporation and ensure uniform film thickness, and a cup design with an exhaust unit and supply nozzle facilitates easy substrate loading and unloading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional spin chuck is used for spin coating on a polygonal substrate, then the substrate can be rotated to enable coating, but the solvent evaporation becomes uneven at corner portions causing increased film thickness and poor uniformity
Solution Approach 1:
The invention introduces air flow control members positioned at specific locations (excluding corner portions) to create localized air flow patterns. This local modification of air flow characteristics suppresses solvent evaporation specifically at corner portions where it is excessive, while maintaining appropriate evaporation rates at other areas, thereby achieving uniform film thickness across the entire substrate surface
Solution Approach 2:
The air flow control members act as intermediary elements between the spin chuck and the substrate. These members mediate the air flow environment around the substrate during rotation, creating a controlled atmosphere that prevents harmful localized evaporation at corners while allowing the coating process to proceed normally
2Productivity
If a conventional spin chuck with a recessed loading area is used, then substrate loading can be performed, but the loading/unloading process becomes complicated and throughput is reduced
Solution Approach 1:
The invention removes the complicated recessed loading structure from the spin chuck design. By eliminating this feature, the loading and unloading of substrates becomes simpler and more direct, reducing the number of steps required and improving operational efficiency without compromising the air flow control functionality
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 apparatus achieves high in-surface uniformity of the resist film thickness and simplifies the loading/unloading process, reducing throughput issues and improving the precision of the mask pattern line-width, while maintaining a uniform film profile across the substrate.
Implementation Method 1
the substrate G is rotated so that a helical air flow pattern is generated on a surface of the substrate G, to thereby rapidly remove solvent (thinner) ambient from the surface of the substrate G
Implementation Method 2
an exhaust unit for evacuating an inside of the cup
Implementation Method 3
at least one air flow control member provided on the spin chuck, the air flow control member being disposed adjacent to a periphery of the polygonal substrate supported on the spin chuck
Data Source
AI summary
In a liquid processing apparatus for forming a coating film on a polygonal substrate by spin coating in an ambient with a descending clean air flow, a spin chuck includes a support plate for substantially horizontally supporting the substrate thereon. Air flow control members are provided on the spin chuck such that the air flow control member being disposed adjacent to a periphery of the polygonal substrate supported on the spin chuck, wherein the air flow control member is not provided near corner portions of the substrate supported on the spin chuck. The liquid processing apparatus may includes an air flow regulation ring which is provided with an air inlet having an opening surrounding an outer periphery of the air flow control member, wherein the air inlet communicates with the exhaust unit.