Photoresist Developer Composition for Residue Reduction
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing feature size due to tight process windows in photolithographic processing, leading to increased line width roughness and defects caused by resist scum and residue in photoresist patterns.
Innovation Solution
A novel photoresist composition and developer system that includes a cross-linking agent and specific solvents with Hansen solubility parameters, along with an acid or base, to enhance chemical differences between exposed and unexposed regions, reducing residue and scum, and improving pattern definition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional photolithographic processing is used to reduce feature size, then device density increases, but line width roughness and defects increase due to resist scum and residue
Solution Approach 1:
The patent changes the chemical parameters of the developer solution by incorporating specific additives (chelating agents, surfactants, and complexing agents) that modify the developer's interaction with the photoresist material. This enables effective removal of resist residue and scum while maintaining smooth line widths, thus resolving the contradiction between increasing device density and maintaining manufacturing precision
Solution Approach 2:
The developer composition uses a composite formulation combining multiple functional components: organic solvents, bases, chelating agents, surfactants, and complexing agents. This composite material approach allows the developer to simultaneously achieve multiple functions: removing exposed resist, preventing residue formation, and maintaining pattern definition, thereby enabling higher device density without increasing line width roughness
2Productivity
If conventional photolithographic processing is used to reduce feature size, then device density increases, but defects increase due to resist scum and residue
Solution Approach 1:
The patent modifies the chemical parameters of the developer by adding chelating agents and complexing agents that specifically target and bind to metal ions and organic residues. This parameter change enables the developer to effectively remove resist scum and prevent defect formation, allowing increased device density while maintaining or improving process reliability
Solution Approach 2:
The chelating agents and surfactants in the developer act as intermediary substances that facilitate the removal of resist residue and scum from the patterned features. These intermediaries bind to contaminants and enable their dissolution and removal, thereby reducing defects and improving reliability as device density increases
3Productivity
If process windows are tightened to enable smaller features, then device density increases, but pattern definition deteriorates due to resist scum and residue
Solution Approach 1:
The patent changes the chemical parameters of the developer solution by incorporating surfactants and complexing agents that improve wetting and dissolution characteristics. This enables the developer to effectively remove resist material even with tighter process windows, maintaining sharp pattern definition while enabling smaller feature sizes and higher device density
Solution Approach 2:
The composite developer formulation combines multiple agents that work synergistically: surfactants improve wetting and penetration, chelating agents bind contaminants, and complexing agents stabilize removed material. This composite approach maintains excellent pattern definition even when process windows are tightened for smaller features, enabling increased device density without sacrificing manufacturing precision
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 effectively reduces resist scum and residue, leading to improved semiconductor device yield and feature density with reduced defects, enabling more efficient photolithography processes.
Implementation Method 1
The photoresist layer is patternwise crosslinked to form a latent pattern in the photoresist layer
Implementation Method 2
The latent pattern is developed by applying a developer composition to remove the uncrosslinked portion of the photoresist layer
Data Source
AI summary
A method of forming a pattern in a photoresist includes forming a photoresist layer over a substrate, and selectively exposing the photoresist layer to actinic radiation to form a latent pattern. The latent pattern is developed by applying a developer composition to the selectively exposed photoresist layer to form a pattern. The developer composition includes a first solvent having Hansen solubility parameters of 15<δd<25, 10<δp<25, and 6<δh<30; an acid having an acid dissociation constant, pKa, of −15<pKa<5, or a base having a pKa of 40>pKa>9.5; and a second solvent having a dielectric constant greater than 18. The first solvent and the second solvent are different solvents.