Resist Composition Ionic Compound Back Scattering Suppression
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Solution Overview
Problem
Current resist compositions fail to form ultrafine patterns with high resolution and low line width roughness while maintaining high vacuum stability and rectangularity of pattern profiles, especially when using electron beam exposure, due to issues like back scattering and insufficient suppression of acid-unstable group decomposition in unexposed areas.
Innovation Solution
An actinic ray-sensitive or radiation-sensitive resin composition containing a specific resin with a repeating unit and an ionic compound having a particular structure, which enhances diffusibility and low volatility, improving resolution, rectangularity, and reducing pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the accelerating voltage of electron beam is increased to reduce forward scattering influence, then the resolution is improved, but the back scattering influence increases causing resolution reduction
Solution Approach 1:
The patent introduces a basic compound as an intermediary substance that mediates between the electron beam and the resist film. This basic compound suppresses the harmful back scattering effects by neutralizing the influence of scattered electrons, thereby allowing high accelerating voltage to be used without suffering from increased back scattering resolution degradation
Solution Approach 2:
The patent changes the chemical parameters of the resist film by incorporating specific basic compounds with particular pKa values and molecular structures. This chemical parameter modification enables the film to withstand high electron beam energies while suppressing back scattering effects, thus achieving high resolution at high accelerating voltages
2Reliability
If amine is used as basic compound to suppress acid-unstable group decomposition, then the decomposition is suppressed, but the amine evaporates from the film causing insufficient suppression in unexposed area
Solution Approach 1:
The patent changes the physical and chemical parameters of the basic compound by selecting compounds with specific boiling points and pKa values. The chosen basic compounds have sufficiently high boiling points to prevent evaporation during resist film formation, exposure, and heating steps, while maintaining effective suppression of acid-unstable group decomposition in the unexposed area
Solution Approach 2:
The patent replaces the volatile amine basic compound with non-volatile basic compounds that remain in the film throughout the process. This substitution eliminates the evaporation problem while maintaining the essential function of suppressing decomposition reactions, effectively replacing a temporary/basic component with a persistent one
3Adaptability or versatility
If heavy atom containing light-shielding film is present as underlayer to enable photomask blank patterning, then the photomask function is achieved, but the back scattering influence from underlayer reflection increases
Solution Approach 1:
The patent introduces a basic compound as an intermediary layer between the heavy atom light-shielding film and the resist film. This basic compound acts as a mediator that suppresses the back scattering effects generated by the heavy atom underlayer, enabling successful patterning of photomask blanks despite the presence of the light-shielding film
Solution Approach 2:
The patent converts the harmful back scattering effect generated by the heavy atom underlayer into a beneficial process by using the basic compound to neutralize the scattered electrons. The previously harmful back scattering is transformed into a controlled chemical reaction that suppresses unwanted decomposition, allowing the heavy atom underlayer to serve its photomask function without causing resolution degradation
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 composition achieves high vacuum PED stability, high resolution, and low line width roughness, along with reduced occurrence of bridges and pattern collapse, enabling the formation of ultrafine patterns with improved rectangularity.
Implementation Method 1
which enhances diffusibility and low volatility, improving resolution, rectangularity, and reducing pattern collapse
Implementation Method 2
suppression of the decomposition reaction of the acid-unstable group in the unexposed area
Data Source
AI summary
There is provided an actinic ray-sensitive or radiation-sensitive resin composition containing: a resin (A) containing a repeating unit represented by a specific formula (1), and an ionic compound (B) represented by a specific formula (2), a resist film formed by using the actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method including: (a) a step of forming the resist film, (b) a step of exposing the film, and (c) a step of developing the exposed film using a developer to form a pattern.