Negative-Tone Resist Composition for High-Resolution Alkali Development
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Solution Overview
Problem
In the formation of extremely small patterns, such as isolated trench patterns and dense contact holes, the optical strength of resist patterns becomes weak, leading to deteriorated resolution and various defects, and existing methods using organic developing solutions are inferior to alkali developing processes in terms of environment, apparatus, and cost.
Innovation Solution
A method involving a resist composition with a base component that exhibits increased solubility in an alkali developing solution and a photo-base generator component, where the exposed portions are retained and unexposed portions are dissolved using an alkali developing solution, with a specific photo-base generator component to improve sensitivity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If organic developing solution is used to form negative resist patterns, then resolution can be improved, but environment, apparatus, and cost are worsened
Solution Approach 1:
The patent inverts the conventional positive-tone development process by using a base component that exhibits increased solubility in alkali developing solution under the action of acid, combined with a photo-base generator that produces base upon exposure. This causes unexposed portions to be dissolved while exposed portions remain, forming negative-tone patterns with high resolution using environmentally friendly alkali developing solutions instead of organic solvents.
Solution Approach 2:
The patent changes the chemical parameters of the developing process by selecting specific base components with controlled solubility characteristics in alkali solutions and using photo-base generators with appropriate base production efficiency. This parameter optimization enables negative-tone development with alkali solutions to achieve resolution comparable to organic developing solutions while eliminating their environmental and operational drawbacks.
2Ease of manufacture
If alkali developing solution is used for negative resist patterns, then environment and cost are improved, but resolution and pattern shape are worsened
Solution Approach 1:
The patent applies local quality by selecting base components with specific solubility characteristics that respond differently to acid and base environments in different regions of the resist film. The base component exhibits increased solubility in alkali developing solution only under specific conditions (when acid is present from photoacid generator), enabling selective dissolution of unexposed portions while maintaining the integrity of exposed portions, thus achieving high-resolution negative patterns.
Solution Approach 2:
The patent uses a composite resist composition containing multiple functional components: a base component (exhibiting increased solubility in alkali developing solution under acid action), a photo-base generator (producing base upon exposure), and optionally a photoacid generator (producing acid upon exposure). This composite system synergistically combines the advantages of alkali developing solutions with the resolution capabilities needed for negative-tone high-resolution patterning.
3Productivity
If conventional photoacid generator is used in alkali developing process, then sensitivity is insufficient, but using photo-base generator improves sensitivity and resolution
Solution Approach 1:
The patent introduces a photo-base generator as an intermediary substance that converts light energy into chemical base, which then mediates the solubility change of the base component in the alkali developing solution. This intermediary mechanism enables high sensitivity by using the base component's enhanced solubility response to acid, while the photo-base generator provides the necessary base production efficiency to achieve both high sensitivity and high resolution in the same process.
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 method enables the formation of high-resolution negative-tone resist patterns with excellent shape and sensitivity, addressing the limitations of existing methods by optimizing the alkali developing process.
Implementation Method 1
a photo-base generator component that generates a base upon exposure
Implementation Method 2
a base component that exhibits increased solubility in an alkali developing solution by the action of acid
Data Source
AI summary
A resist composition used in a method of forming a resist pattern including applying a resist composition comprising a base component that exhibits increased solubility in an alkali developing solution and a photo-base generator component to a substrate to form a resist film; subjecting the resist film to exposure; baking after subjecting the resist film to exposure, wherein at an exposed portion of the resist film, the base generated from the photo-base generator component upon exposure and an acid provided to the resist film in advance are neutralized, and at an unexposed portion of the resist film, the solubility of the base component in an alkali developing solution is increased by the action of acid provided to the resist film in advance; and subjecting the resist film to alkali development, thereby forming a negative-tone resist pattern.