Polyelectrolyte Surface Tuning for Immersion Lithography Defects
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Solution Overview
Problem
Hydrophobic photosensitive and topcoat films in immersion lithography systems repel water, leading to bubble formation and contamination, which distorts images and causes defects during exposure.
Innovation Solution
Treating the surfaces of photoresist and topcoat films with a polyelectrolyte solution to tune their surface energy, making them more hydrophilic and compatible with immersion lithography, thereby improving wettability and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrophobic photoresist and topcoat films are used in immersion lithography, then the films maintain their original properties and are easy to manufacture, but water is repelled leading to bubble formation and image distortion
Solution Approach 1:
The patent applies parameter changes by modifying the surface energy of photoresist and topcoat films through chemical treatment with polyelectrolyte solutions. This treatment changes the surface energy parameter from hydrophobic to hydrophilic, enabling water to wet the film surfaces properly during immersion lithography, thereby eliminating bubble formation and image distortion while maintaining film functionality
Solution Approach 2:
The patent introduces polyelectrolyte solutions as an intermediary substance that mediates between the hydrophobic film surfaces and the aqueous immersion lithography medium. The polyelectrolyte treatment creates a surface layer that is compatible with water, allowing proper wetting and eliminating the harmful interaction between hydrophobic films and water-based immersion media
2Ease of manufacture
If hydrophobic photoresist and topcoat films are used, then manufacturing processes remain simple, but water repulsion causes components to leach into the immersion medium causing defects
Solution Approach 1:
The patent modifies the surface energy parameter of the films through polyelectrolyte treatment, transforming hydrophobic surfaces into hydrophilic surfaces. This parameter change prevents component leaching into the immersion medium by ensuring proper wetting, thereby eliminating contamination and image defects while maintaining manufacturing simplicity
Solution Approach 2:
The patent applies preliminary anti-action by treating the film surfaces with polyelectrolyte solutions before immersion lithography exposure. This pre-treatment creates a protective hydrophilic surface layer that prevents the leaching of film components into the aqueous immersion medium, thereby preventing contamination and image defects before they can occur
3Reliability
If polyelectrolyte solution treatment is applied to photoresist and topcoat films, then surface energy is tuned for better hydrophilicity and immersion lithography compatibility, but an additional processing step is required
Solution Approach 1:
The patent applies universality by developing a polyelectrolyte treatment solution that can be used across multiple film types (photoresist and topcoat films) and is compatible with existing immersion lithography processes. The treatment serves multiple functions: improving wetting, preventing bubble formation, and preventing component leaching, thereby justifying the additional processing step through its broad applicability and multiple benefits
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 solution enhances the compatibility of films with immersion lithography, reduces bubble formation, and increases manufacturing yield by improving developer coverage and etch resistance, while being cost-efficient and applicable to various materials.
Implementation Method 1
forming a layer of photoresist on the substrate; treating the photoresist layer with a polyelectrolyte solution
Implementation Method 2
photosensitive films, such as photoresist, are hydrophobic... it would be advantageous to have a method and solution for tuning surface energies of materials
Implementation Method 3
At least one portion of the photoresist layer treated with the polyelectrolyte solution is exposed to radiation via immersion lithography
Data Source
AI summary
A polyelectrolyte solution for tuning a surface energy and a method for using the polyelectrolyte solution to manufacture an integrated circuit. A substrate is provided and a photosensitive material having a surface energy is formed over the substrate. The substrate may be polysilicon, silicon dioxide, silicon nitride, metal, and the like. The photosensitive material is treated with a polyelectrolyte solution to change the surface energy of the photosensitive material. Treatment techniques for applying the polyelectrolyte solution may include spraying, bathing, rinsing, soaking, or washing. The polyelectrolyte adsorbs to the photosensitive material forming a polyelectrolyte polymer layer on the photosensitive material. The photosensitive material may be a photoresist or a photoresist having a topcoat formed thereon. The photosensitive material is exposed using lithography techniques and processed to form a patterned layer of photosensitive material for use in manufacturing the integrated circuit.