Organic Solvent Developer for Chemically Amplified Resist

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Solution Overview

Problem

Current chemically amplified photoresists face challenges in achieving high resolution and low line edge roughness (LER) while maintaining high photo speed, particularly as semiconductor feature sizes approach 20 nm, and there is a lack of effective organic developers for positive tone chemically amplified resists.

Innovation Solution

The use of a polyhydric alcohol-based organic developer solvent with minimal hydroxide ions, such as ethylene glycol or glycerol, in combination with other solvents like isopropyl alcohol, to develop positive tone images in chemically amplified resists, which allows for polarity-based dissolution rather than ionization, enhancing resolution and LER performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If chemically amplified photoresists are developed in alkaline base solutions, then photo speed is improved, but resolution and line edge roughness deteriorate

Engineering Contradiction:

Improvephoto speedVSAvoidresolution and line edge roughness

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent changes the chemical parameters of the developer solution by using organic solvents (isopropyl alcohol, ethylene glycol, glycerol) instead of traditional aqueous alkaline bases. This parameter change allows the resist to achieve both high photo speed and high resolution simultaneously, as the organic solvent system maintains the chemical amplification mechanism while providing better dissolution control for high-resolution patterning.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite developer system combining multiple organic solvents (isopropyl alcohol as primary solvent, ethylene glycol or glycerol as additives). This composite solvent system provides synergistic effects that optimize both photo speed and resolution, overcoming the limitations of single-component developers.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If high-performance solvent-developed non-chemically amplified resists are used, then resolution and line edge roughness are improved, but photo speed deteriorates

Engineering Contradiction:

Improveresolution and line edge roughnessVSAvoidphoto speed

Core Design Contradiction:

Manufacturing precisionVSSpeed

Solution Approach 1:

The patent merges the advantages of two different resist systems: the high resolution characteristics of solvent-developed non-chemically amplified resists and the high photo speed of chemically amplified resists. By using a chemically amplified resist formulation developed in an organic solvent system, the patent achieves both high resolution and high photo speed, effectively combining the strengths of both approaches.

Inventive Principle:

Principle #5Merging (Combining)

3Speed

If conventional aqueous alkaline developers are used for chemically amplified resists, then photo speed is maintained, but resolution capability deteriorates at feature sizes approaching 20 nm

Engineering Contradiction:

Improvephoto speedVSAvoidresolution capability

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameters of the developer system by transitioning from aqueous alkaline chemistry to organic solvent chemistry. This parameter change enables the system to achieve 20 nm and below resolution while maintaining high photo speed, as the organic solvent system provides better control over dissolution processes at ultra-fine feature sizes.

Inventive Principle:

Principle #35Parameter changes

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

This approach enables the production of high-resolution positive tone images with improved LER and photo speed, overcoming the limitations of alkaline developers and addressing the RLS Tradeoff, suitable for advanced semiconductor lithography and biomolecule patterning.

Implementation Method 1

Methodology Applied

Scientific EffectPolarity-based dissolution: Solvation

Data Source

PatentUS8900802B2Positive tone organic solvent developed chemically amplified resist

Publication Date: 2014.12.02 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Provided is a method for developing positive-tone chemically amplified resists with an organic developer solvent having at least one polyhydric alcohol, such as ethylene glycol and/or glycerol, alone or in combination with an additional organic solvent, such as isopropyl alcohol, and/or water. The organic solvent developed positive tone resists described herein are useful for lithography pattern forming processes; for producing semiconductor devices, such as integrated circuits (IC); and for applications where basic solvents are not suitable, such as the fabrication of chips patterned with arrays of biomolecules or deprotection applications that do not require the presence of acid moieties.