Substrate Treating Apparatus Gas Flow Control
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Solution Overview
Problem
Conventional substrate treating apparatuses face challenges in quickly switching gas flow rates during drying, leading to extended drying times and reduced cleanliness due to particle contamination, as the mass flow controller responds slowly and spinning creates negative pressure, drawing ambient particles towards the substrate center.
Innovation Solution
A substrate treating apparatus with a turntable and control valves that allow for rapid switching between two gas flow rates, increasing the flow rate during drying after completing upper surface treatment, while maintaining the first flow rate during cleaning to prevent contamination and ensure uniform gas distribution radially across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mass flow controller is used to switch the flow rate of drying gas, then the flow rate can be increased for shorter drying time, but the response speed is slow causing a delay of several seconds in switching
Solution Approach 1:
The gas supply system is segmented into multiple independent gas supply mechanisms (first gas supply mechanism with first mass flow controller and second gas supply mechanism with second mass flow controller), each capable of independently controlling gas flow rates. This segmentation allows parallel operation and faster switching by selecting between pre-configured gas supply paths rather than adjusting a single controller.
Solution Approach 2:
The system pre-configures multiple gas supply mechanisms with different flow rate capabilities before the drying process begins. During operation, the appropriate gas supply mechanism is selected and activated in advance, eliminating the delay associated with real-time adjustment of a single mass flow controller.
2Productivity
If the flow rate of drying gas is increased to high flow rate during cleaning treatment, then drying time is shortened, but the treating liquid covering the lower surface is disturbed and protection is insufficient
Solution Approach 1:
The gas supply is segmented into cleaning gas supply and drying gas supply with independent control. During cleaning treatment, only the cleaning gas supply operates at low flow rate to maintain liquid coverage, while during drying treatment, the drying gas supply operates at high flow rate for rapid evaporation without disturbing the protective liquid layer.
Solution Approach 2:
Different gas supply characteristics are applied to different operational phases: low flow rate gas supply is used during cleaning to maintain gentle protection, while high flow rate gas supply is used during drying to achieve rapid drying. Each gas supply mechanism is optimized for its specific function and activated locally in time.
3Productivity
If the flow rate of drying gas is increased to high flow rate, then drying time is reduced, but ambient particles are drawn toward the center of substrate due to negative pressure from spinning
Solution Approach 1:
The gas supply is activated in advance before the substrate spinning reaches high speed, establishing a positive pressure field that counteracts the negative pressure generated by centrifugal force. This preliminary gas supply prevents particle ingress before the harmful effect occurs.
Solution Approach 2:
The gas supply mechanism operates continuously throughout the drying process, maintaining a steady flow that continuously counteracts the negative pressure effect. This continuous gas flow creates a stable pressure field that prevents particle contamination while enabling rapid drying.
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 significantly shortens drying time and enhances the cleanliness of the substrate's lower surface by improving gas flow rate response and preventing particle contamination, ensuring efficient and clean treatment.
Implementation Method 1
a gas supply device for supply the gas; first branch piping with one end thereof connected to the gas supply device, and the other end connected to the other end of the gas supply pipe; second branch piping with one end thereof connected to the gas supply device, and the other end connected to the other end of the gas supply pipe; a first control valve for controlling circulation of the gas through the first branch piping to a first flow rate; a second control valve for controlling circulation of the gas through the second branch piping to a second flow rate higher than the first flow rate
Implementation Method 2
a rotary drive device for spinning the turntable; at a time of upper surface treatment for treating the upper surface of the substrate with the treating device, to supply the treating liquid from the treating liquid supply device and operate the first control valve to supply the gas at the first flow rate from the gas nozzle, while operating the rotary drive device to spin the substrate at a first rotational frequency
Data Source
AI summary
A control device is provided which, at a time of upper surface treatment for treating an upper surface of a substrate with a treating device, supplies a treating liquid from a treating liquid supply source and operates a first control valve to supply a gas at a first flow rate from a gas nozzle, while operating a rotary drive device to spin the substrate at a first rotational frequency, and at a time of drying treatment, after completion of the upper surface treatment, for drying the substrate by increasing the rotational frequency of the rotary drive device to spin the substrate at a second rotational frequency, operates the first control valve and second control valve to supply the gas at a higher flow rate than the first flow rate from the gas nozzle.