Substrate Purge Gas Control to Prevent Drying Mist Contamination
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Solution Overview
Problem
During the drying process in substrate processing, the introduction of cleaning liquid into the gas injection port results in mist formation, which contaminates the substrate, and existing solutions fail to effectively prevent this without compromising gas flow rates or temperature uniformity.
Innovation Solution
A substrate processing apparatus with a purge gas nozzle and flow rate controller that discharges purge gas into the substrate lower space at a controlled flow rate to cancel negative pressure, preventing mist reattachment and maintaining temperature uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas is blown out from the gas injection port at a high flow rate to promote drying, then drying efficiency is improved, but cleaning liquid is blown out like mist and contaminates the substrate
Solution Approach 1:
The system performs preliminary action by detecting the presence of cleaning liquid in the gas injection port before gas discharge begins, and preemptively stops the cleaning liquid supply or activates a purge mechanism to prevent mist formation and substrate contamination
Solution Approach 2:
The system uses sensors to detect cleaning liquid presence in the gas injection port and provides feedback to the control system, which adjusts gas flow rate or cleaning liquid supply accordingly to prevent contamination while maintaining drying efficiency
2Object-affected harmful factors
If gas flow rate is reduced during cleaning process to prevent mist formation, then substrate contamination is prevented, but drying efficiency is compromised
Solution Approach 1:
The system dynamically adjusts gas flow rate based on process stage and cleaning liquid presence detection, using high flow rate for drying when port is clear, and low flow rate when cleaning liquid is detected, optimizing both contamination prevention and drying efficiency
Solution Approach 2:
The system implements periodic action by alternating between cleaning process with low gas flow and drying process with high gas flow, using detection signals to determine when to switch between these periodic states to achieve both contamination prevention and efficient 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
Effectively reduces particle contamination on the substrate's lower surface by maintaining optimal gas flow and pressure conditions, ensuring efficient drying and cleanliness without impairing temperature uniformity.
Implementation Method 1
a cup exhaust passage configured to suction an atmosphere in the liquid receiving cup
Implementation Method 2
a purge gas flow rate controller configured to control a first flow rate of the purge gas discharged from the purge gas nozzle
Implementation Method 3
a rotary driver configured to rotationally drive the substrate holder about a vertical axis
Implementation Method 4
a processing liquid nozzle configured to supply a processing liquid to the substrate held by the substrate holder
Implementation Method 5
a liquid receiving cup provided around the substrate holder and configured to receive the processing liquid scattered from the substrate held and rotated by the substrate holder
Data Source
AI summary
An apparatus includes: a substrate holder including a base member and configured to hold a substrate so as to be spaced apart upward from the base member; a rotary driver configured to rotationally drive the substrate holder; a processing liquid nozzle configured to supply a processing liquid to the substrate; a liquid receiving cup configured to receive the processing liquid scattered from the substrate; a cup exhaust passage configured to suction an atmosphere in the liquid receiving cup; a purge gas nozzle configured to discharge a purge gas into a space formed between the substrate and the base member; a purge gas flow rate controller configured to control a flow rate of the purge gas discharged from the purge gas nozzle; and a controller configured to control at least an operation of the purge gas flow rate controller.