Silicon-Containing Resist Composition for ArF Patterning
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Solution Overview
Problem
In the field of photolithography, particularly in the bilayer resist process, there is a challenge in forming finer patterns without pattern collapse due to swelling and achieving high rectangularity and resistance to etching, while avoiding T-top profiles and standing waves, which affect the resolution and depth of focus.
Innovation Solution
A silicone resin-containing resist composition is developed, incorporating structural units with a carboxylic acid protected by an acid labile group, a hydroxyl group with fluorine substitution, and a lactone structure, along with a specific organic acid generator other than onium salts, to enhance dissolution contrast, prevent swelling, and maintain etching resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the resist coating is made thinner to achieve finer feature size, then the resolution performance is improved, but the etching resistance becomes weaker
Solution Approach 1:
The patent divides the resist system into two separate layers: a silicon-containing resist coating for pattern formation and an aromatic resin intermediate coating for etching protection. This segmentation allows each layer to be optimized independently - the silicon-containing layer can be made thin for high resolution while the aromatic resin layer provides the necessary etching resistance.
Solution Approach 2:
The patent uses composite materials by combining silicon-containing resin and aromatic resin in a bilayer structure. The silicon-containing resin provides good pattern definition and resolution, while the aromatic resin provides high etching resistance to fluorine and chlorine gas plasma, creating a composite system that achieves both fine feature size and strong etching protection.
2Manufacturing precision
If the resist coating is made thinner to achieve finer feature size, then the resolution performance is improved, but the pattern collapse due to swelling occurs
Solution Approach 1:
The patent segments the resist system into two layers where the silicon-containing resist coating (50-200 nm) provides fine pattern definition while the thicker aromatic resin intermediate coating (200-500 nm) provides structural support and prevents pattern collapse during development and etching processes.
Solution Approach 2:
The aromatic resin intermediate coating acts as an intermediary layer between the silicon-containing resist pattern and the substrate. It provides mechanical support to prevent pattern collapse while being selectively removed during oxygen plasma etching to transfer the pattern to the substrate.
3Productivity
If onium salts are used as acid generator to improve sensitivity, then the dissolution contrast is improved, but the T-top profile is generated
Solution Approach 1:
The patent changes the chemical parameters of the acid generator from onium salts to non-onium salt compounds (such as sulfone, sulfonate, or carboxylate esters of diazomethane). This parameter change maintains adequate sensitivity while eliminating the excessive dissolution inhibition that causes T-top profiles, achieving a balance between productivity and pattern quality.
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 enables the formation of patterns with high rectangularity and improved etching resistance, preventing pattern collapse and T-top profiles, thus maintaining high resolution and aspect ratio without generating standing waves, suitable for ArF exposure and oxygen reactive etching.
Implementation Method 1
a carboxyl group-containing structural unit (2) which has a carboxyl group protected with an acid labile group
Implementation Method 2
a hydroxyl group-containing structural unit (1) which has a hydroxyl group and a fluorine atom on a carbon atom adjacent to the carbon atom bearing the hydroxyl group
Implementation Method 3
a lactone structural unit (3) which has a lactone ring
Implementation Method 4
exposed to a pattern of high energy radiation, and heat treating the exposed resist layer
Implementation Method 5
oxygen-reactive ion etching is carried out. Then the silicon-containing resin is converted to silicon oxide having high resistance to oxygen plasma etching
Data Source
AI summary
A resist composition is provided comprising a polysiloxane, a specific acid generator, a nitrogen-containing organic compound, and a solvent. The resist composition exerts high-resolution performance without the problem of a T-top profile and is suited for the bilayer resist process using ArF exposure.