Anti-Static Liquid Substrate Processing Prevents Electrostatic Damage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate processing technologies face challenges in preventing damage due to the movement of electric charges during processes using processing liquids, particularly with substrates that are electrically charged after drying processes like dry etching or plasma CVD, which can lead to heat generation and damage when low-resistivity liquids like SPM are applied.
Innovation Solution
A substrate processing apparatus that includes a substrate holding part, a processing liquid supply part, and an anti-static liquid contacting part to bring both main surfaces of the substrate into contact with an anti-static liquid of higher electrical resistivity than the processing liquid, maintaining a wetted state to gently move static electricity and prevent damage during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ionizer is used to remove static electricity from the substrate before supplying processing liquid, then static electricity removal efficiency is improved, but when the amount of electrostatic charges is too large, it becomes hard to efficiently remove static electricity
Solution Approach 1:
The patent introduces an intermediary liquid (first liquid) with intermediate electrical resistivity between the high-resistivity substrate and the low-resistivity processing liquid. This intermediary acts as a mediator to gradually discharge static electricity, preventing direct rapid discharge that causes heat generation and damage.
Solution Approach 2:
The patent changes the electrical resistivity parameter by introducing a liquid with intermediate resistivity values. This gradual transition in resistivity allows controlled discharge of large electrostatic charges without causing harmful heat generation, solving the limitation of ionizers with large charge amounts.
2Productivity
If a processing liquid with low electrical resistivity (such as SPM liquid) is supplied onto the substrate, then processing effectiveness is improved, but electric charges rapidly move from the device to the processing liquid causing heat generation and damage
Solution Approach 1:
The patent performs preliminary action by supplying a first liquid with intermediate electrical resistivity before supplying the processing liquid. This preliminary step gradually discharges static electricity and maintains a wetted state, preventing rapid charge movement and heat generation when the low-resistivity processing liquid is subsequently applied.
Solution Approach 2:
The first liquid with intermediate resistivity serves as a cushioning layer that absorbs and gradually dissipates electrostatic charges before the processing liquid contact. This beforehand cushioning prevents the harmful rapid discharge that would occur with direct processing liquid application.
3Reliability
If only one main surface of the substrate is brought into contact with anti-static liquid, then static electricity removal is partially achieved, but the other main surface remains charged and vulnerable to damage
Solution Approach 1:
The patent merges the treatment of both main surfaces by supplying the first liquid to contact both surfaces simultaneously or sequentially. This combined approach ensures comprehensive static electricity removal from all vulnerable surfaces before processing liquid application.
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 reduces the surface potential of the substrate, preventing damage from electric charge movement and ensuring efficient static elimination without heat generation, thereby protecting the substrate during processing with low-resistivity liquids like SPM.
Implementation Method 1
an anti-static liquid having electrical resistivity higher than that of the processing liquid
Implementation Method 2
the processing liquid which is electrically charged by the frictional electrification phenomenon between the processing liquid and a processing liquid nozzle
Implementation Method 3
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) and damage may be caused in the device by heat generation due to the movement of the electric charges
Data Source
AI summary
A substrate processing apparatus comprises a single-substrate processing apparatus for processing substrates one by one, and an anti-static liquid storage part for storing an anti-static liquid having electrical resistivity maintained at target electrical resistivity higher than the electrical resistivity of an SPM liquid. A plurality of substrates held in a cartridge are immersed in the anti-static liquid inside the anti-static liquid storage part and both main surfaces of the substrate entirely come into contact with the anti-static liquid. From the substrates, static electricity is relatively gently removed. Then, after the static elimination process are finished, a processing liquid supply part supplies the SPM liquid onto an upper surface of the substrate and an SPM process is thereby performed. It is thereby possible to prevent a large amount of electric charges from rapidly moving from the substrate to the SPM liquid and also possible to prevent any damage to the substrate.