Substrate Liquid Supply Using Negative Pressure to Prevent Bubbles
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Solution Overview
Problem
Existing substrate processing methods generate excessive bubbles in liquids due to high gas pressure, leading to inefficiencies and defects in film thickness during applications like photoresist coating.
Innovation Solution
A substrate processing apparatus and method that utilize a negative pressure forming unit to stabilize liquid delivery by maintaining pressure between normal and 5 kPa higher, using inert gas and a controlled flow system to prevent bubble formation and ensure consistent liquid supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high pressure gas is supplied to the bottle to deliver liquid to the trap tank, then the liquid delivery speed is improved, but a large amount of bubbles are generated in the liquid
Solution Approach 1:
Instead of using positive pressure to push liquid from the bottle to the trap tank, the patent applies negative pressure (vacuum) to the trap tank. This inversion of the pressure approach allows liquid to be drawn into the trap tank without the violent pressure changes that cause bubble formation, while still maintaining efficient liquid delivery.
Solution Approach 2:
The patent changes the pressure parameter from high positive pressure (tens of kPa) to controlled negative pressure in the trap tank. This parameter change enables liquid delivery at appropriate speed while preventing the excessive bubble generation caused by high positive pressure.
2Quantity of substance
If high pressure gas is supplied to the bottle, then the liquid can be delivered to the trap tank, but the dissolved gas amount in the liquid increases
Solution Approach 1:
The patent inverts the pressure approach by applying negative pressure to the trap tank instead of positive pressure to the bottle. This prevents excessive gas dissolution in the liquid while maintaining effective liquid delivery to the trap tank.
3Speed
If high pressure gas is used to supply liquid, then the liquid flow rate is improved, but the film thickness uniformity deteriorates
Solution Approach 1:
By applying negative pressure to the trap tank instead of positive pressure to the supply system, the patent achieves smooth liquid flow that maintains both adequate flow rate and uniform film thickness without the turbulence and bubble formation caused by high pressure gas supply.
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
Improves substrate processing efficiency by preventing large bubble generation and ensuring a consistent liquid supply, thereby maintaining film thickness and application accuracy.
Implementation Method 1
a negative pressure forming unit for forming negative pressure in the interior space of the trap tank and delivering the liquid in the storage space of the bottle to the trap tank
Implementation Method 2
a pump installed in the supply pipe downstream of the trap tank and providing flow pressure to the fluid flowing in the supply pipe
Implementation Method 3
a gas supply unit for supplying gas to the storage space... the gas supply unit may supplies the gas so that the pressure in the storage space is maintained between normal pressure and pressure 5 kPa higher than the normal pressure
Data Source
AI summary
The apparatus includes a processing unit for processing a substrate; and a liquid supply unit for supplying a liquid to a substrate disposed in the processing unit, in which the liquid supply unit includes: a bottle in which a storage space for storing a liquid is formed; a supply pipe for providing a path through which the liquid in the bottle flows to the processing unit; a trap tank installed in the supply pipe and having an interior space in which the liquid delivered from the bottle is stored; a pump installed in the supply pipe downstream of the trap tank and providing flow pressure to the fluid flowing in the supply pipe; and a negative pressure forming unit for forming negative pressure in the interior space of the trap tank and delivering the liquid in the storage space of the bottle to the trap tank.