Atmospheric Plasma Reactive Species Generator for Substrate Cleaning
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Solution Overview
Problem
Current cleaning technologies in the semiconductor and photomask industries are inadequate for removing small particles and residues from substrates, leading to yield loss, cost issues, and substrate damage, particularly in next-generation lithography and EUV mask technologies, where stringent cleanliness specifications are required.
Innovation Solution
A dry cleaning apparatus and method using a reactive species generator that produces monatomic oxygen, monatomic hydrogen, or other reactive species in a plasma, combined with cryogenic CO2 particles, for localized removal of organic and inorganic contaminants without exposing the entire substrate to corrosive etchants, operating at atmospheric pressure to avoid vacuum-related contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional physical cleaning techniques (brush scrubbing, dry argon ice cleaning, CO2 aerosol) are used, then particle removal capability is improved, but substrate damage risk increases and small particles (1 micrometer or smaller) cannot be effectively removed
Solution Approach 1:
The patent replaces mechanical brush scrubbing and physical aerosol impact with a chemical cleaning mechanism using plasma-generated reactive species. The plasma chemically converts organic contaminants into volatile gaseous products that can be removed without mechanical contact, thereby eliminating substrate damage from mechanical forces while achieving effective particle and residue removal including submicron particles
Solution Approach 2:
The patent changes the cleaning mechanism from physical/chemical hybrid (aerosol + mechanical impact) to purely chemical (plasma reactive species). By generating reactive species through plasma at atmospheric pressure, the cleaning action transitions from momentum-transfer-based particle ejection to chemical conversion of contaminants into removable volatile products, enabling effective cleaning of 1 micrometer or smaller particles without substrate damage
2Manufacturing precision
If plasma cleaning is used to remove organic contaminants, then cleaning effectiveness is improved, but vacuum system complexity and contamination risk from pump down/venting increase
Solution Approach 1:
The patent uses atmospheric pressure plasma instead of vacuum plasma, eliminating the need for vacuum systems. The plasma is generated directly in atmospheric air or controlled atmosphere, removing organic contaminants through reactive species without requiring pump down and venting cycles. This eliminates vacuum-related contamination risks and simplifies the system by removing vacuum pumps, chambers, and associated controls
Solution Approach 2:
The patent extracts and removes the vacuum system entirely from the plasma cleaning process. By demonstrating that atmospheric pressure plasma can effectively generate reactive species for contaminant removal, the invention eliminates the vacuum subsystem including pumps, chambers, and control mechanisms, thereby removing the source of vacuum-related contamination and reducing overall system complexity
3Manufacturing precision
If wet chemical cleaning techniques are used, then residue removal capability is improved, but environmental safety issues, cost, and potential substrate damage increase
Solution Approach 1:
The patent replaces wet chemical cleaning with plasma-based chemical cleaning. Instead of using liquid chemicals that require disposal and can damage substrates, the plasma generates reactive species that chemically convert organic residues into volatile gaseous products. This eliminates the need for wet chemicals, removes environmental disposal issues, and prevents substrate damage from chemical etching while maintaining effective residue removal capability
Solution Approach 2:
The patent changes the cleaning medium from liquid wet chemicals to gaseous plasma reactive species. This parameter change eliminates the environmental and safety issues associated with liquid chemical handling, storage, and disposal. The plasma process converts residues into volatile gases that can be vented safely, removing the need for chemical waste management systems and reducing substrate exposure to harmful liquids
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
Enables efficient, cost-effective, and safe removal of contaminants from substrates, including pellicle adhesive residues and carbon contamination, without damaging the substrate, while maintaining high cleanliness standards and reducing operational costs.
Implementation Method 1
Plasma cleaning, on the other hand, is based on generating reactive species to eliminate organic contaminants by chemically converting the organic contaminants into volatile gaseous products. The reactive species used for plasma cleaning may include, for example, radicals or excited atoms created from oxygen, hydrogen, combinations thereof
Implementation Method 2
generating reactive species to eliminate organic contaminants by chemically converting the organic contaminants into volatile gaseous products
Implementation Method 3
When the solid aerosol particle collides with a contaminant, the resulting momentum transfer generates a force on the contaminant that may overcome an adhesion force between the particle and a substrate, and thereby remove the particle or residue from the surface of the substrate
Implementation Method 4
dissociating the at least one reactive precursor into at least one reactive species in response to the electric field
Data Source
AI summary
A substrate dry cleaning apparatus, a substrate dry cleaning system, and a method of cleaning a substrate are disclosed. The substrate dry cleaning system includes a substrate support and a reactive species generator. The reactive species generator includes a first conduit defining a first flow channel that extends to an outlet of the first conduit, the outlet of the first conduit facing the substrate support, a first electrode, a second electrode facing the first electrode, the first flow channel disposed between the first electrode and the second electrode, a first inert wall disposed between the first electrode and the first flow channel, and a second inert wall disposed between the second electrode and the first flow channel.