Cleaning Substrate for Lithography Contamination Removal
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Solution Overview
Problem
Contamination of substrate support surfaces in lithographic apparatuses, particularly in immersion lithography, leads to defects in pattern projection due to particles or flakes from resist materials, making it difficult to accurately project radiation beams.
Innovation Solution
A cleaning substrate with a material configured to chemically react with contamination, such as silica, is used to dislodge and remove contamination from apparatus parts, either in situ or near in situ, by physical contact and chemical reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If immersion lithography is used to increase numerical aperture, then resolution is improved, but contamination from particles and resist flakes increases
Solution Approach 1:
The patent applies oxygen plasma treatment to convert the harmful organic contamination (resist flakes, particles) into volatile oxidation products that can be removed. The plasma environment transforms the contamination problem into a beneficial cleaning process, where the same immersion lithography environment that causes contamination also enables its removal through controlled plasma exposure
Solution Approach 2:
The patent changes the chemical state of the contamination by exposing it to oxygen plasma, which oxidizes organic materials at controlled temperatures. This parameter change (chemical oxidation) converts adhered contamination into removable oxidized products, allowing cleaning without damaging the substrate or support surface
2Object-affected harmful factors
If substrate support surfaces are cleaned by disassembly, then contamination is removed, but downtime increases and risk of further contamination occurs
Solution Approach 1:
The patent enables the substrate support surface to clean itself by incorporating oxygen plasma treatment directly into the lithography process cycle. The system performs self-cleaning without external intervention or disassembly, using the plasma environment to automatically remove contamination from the support surfaces while they remain in place
Solution Approach 2:
The patent applies oxygen plasma treatment as a preliminary or intermediate cleaning step before contamination can significantly impact pattern projection. By cleaning the surfaces proactively during the lithography process rather than waiting for severe contamination, the system prevents defects before they occur, reducing the need for extensive disassembly cleaning
3Object-affected harmful factors
If oxygen plasma is used to clean substrate support surfaces, then contamination is removed, but process complexity increases
Solution Approach 1:
The patent merges the oxygen plasma cleaning function with the existing lithography process by integrating plasma generation capabilities into the lithography tool. The cleaning process is combined with the pattern projection sequence, allowing both functions to share the same hardware platform and control system, thereby minimizing additional complexity
Solution Approach 2:
The patent makes the lithography apparatus multi-functional by enabling it to perform both pattern projection and substrate support surface cleaning with the same equipment. The oxygen plasma system serves dual purposes: maintaining the immersion environment and cleaning contamination, reducing the need for separate dedicated cleaning equipment
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
The method effectively reduces contamination on apparatus parts, minimizing defects in pattern projection and maintaining the effectiveness of the lithographic process without the need for disassembly, thus reducing downtime and risk of further contamination.
Implementation Method 1
providing a cleaning substrate into contact with the part of the apparatus while the part is attached to the apparatus, the cleaning substrate comprising a material configured to chemically react with the contamination; and dislodging contamination on the part of the apparatus by chemical reaction between the material and the contamination
Data Source
AI summary
A method of dislodging contamination from a part of an apparatus used in a patterning process, the method including: providing a cleaning substrate into contact with the part of the apparatus while the part is attached to the apparatus, the cleaning substrate comprising a material configured to chemically react with the contamination; and dislodging contamination on the part of the apparatus by chemical reaction between the material and the contamination.