Anti-Static Liquid Puddling for Substrate Processing
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Solution Overview
Problem
Existing substrate processing technologies face challenges in preventing damage due to electric charge movement and adverse effects from the mixture of processing liquids, particularly with sulfuric acid/hydrogen peroxide mixtures, which can cause heat generation and ununiform processing.
Innovation Solution
A substrate processing apparatus that includes a substrate holding part, a processing liquid supply part, an anti-static liquid supply part with higher electrical resistivity, and a control part to puddle the substrate with an anti-static liquid before applying the processing liquid, maintaining target electrical resistivity to prevent charge damage and mixture adverse effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water is supplied onto the substrate before the process using processing liquid, then static electricity on the substrate is removed, but heat of reaction between sulfuric acid in the processing liquid and water causes damage to the substrate
Solution Approach 1:
The patent introduces an intermediary liquid (alcohol or organic solvent) between the water and the processing liquid. This intermediary liquid serves as a mediator that removes static electricity from the substrate without causing harmful heat of reaction when the processing liquid is subsequently supplied, thus resolving the contradiction between removing static electricity and preventing heat damage.
Solution Approach 2:
The patent extracts the harmful component (water) from the anti-static liquid and replaces it with an organic solvent or alcohol that does not cause heat of reaction with sulfuric acid. This extraction of the problematic substance while retaining the desired function (static electricity removal) resolves the contradiction.
2Reliability
If water-diluted processing liquid is used to remove static electricity, then static electricity is removed, but the concentration uniformity of the processing liquid deteriorates
Solution Approach 1:
The patent extracts water from the processing liquid formulation used for anti-static purposes and replaces it with organic solvents or alcohols. This ensures that the processing liquid maintains its intended concentration and composition for etching or cleaning, while still achieving static electricity removal through the alternative liquid medium.
Solution Approach 2:
The patent applies different liquid compositions for different purposes: an organic solvent or alcohol specifically for anti-static treatment, and the original concentrated processing liquid for the actual processing. This local differentiation of liquid properties ensures both static electricity removal and processing uniformity without compromise.
3Reliability
If processing liquid with low electrical resistivity is supplied onto the substrate, then electric charges are rapidly discharged, but heat generation due to charge movement causes damage in the device
Solution Approach 1:
The patent uses an intermediary liquid (organic solvent or alcohol) as a mediator between the charged substrate and the low-resistivity processing liquid. This intermediary provides a controlled path for charge discharge that reduces rapid heat generation, allowing safe static electricity removal without direct contact between the processing liquid and the substrate surface.
Solution Approach 2:
The patent applies a cushioning layer of organic solvent or alcohol on the substrate before supplying the processing liquid. This beforehand cushioning prevents direct interaction between the processing liquid and substrate charges, cushioning the charge discharge process to prevent thermal damage while still achieving electrostatic removal.
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 effectively prevents substrate damage from electric charge movement and ensures uniform processing by gently removing static electricity and controlling the ion concentration of the anti-static liquid, thereby maintaining the substrate's integrity and processing quality.
Implementation Method 1
the electric charges in the device rapidly move from the device to the processing liquid (in other words, the electric charges are discharged into the processing liquid)
Implementation Method 2
controlling the ion concentration of the anti-static liquid to maintain the electrical resistivity of the anti-static liquid at the target electrical resistivity
Implementation Method 3
damage may be caused in the device by heat generation due to the movement of the electric charges
Data Source
AI summary
In a substrate processing apparatus, an anti-static liquid supply part supplies the anti-static liquid having electrical resistivity higher than that of an SPM liquid onto a substrate to puddle an entire upper surface of the substrate with the anti-static liquid, to thereby gradually remove static electricity from the substrate. Then, the processing liquid supply part supplies the SPM liquid onto the substrate to thereby perform an SPM process. In the SPM process, it is thereby possible to prevent a large amount of electric charges from rapidly moving from the substrate to the SPM liquid and prevent any damage to the substrate. Further, by maintaining the electrical resistivity of the anti-static liquid at the target electrical resistivity, it is possible to increase the static elimination efficiency of the substrate and shorten the time required for the static elimination process within the limits of causing no damage to the substrate.