Resist Composition Suppressing Acid Diffusion for High Resolution
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Solution Overview
Problem
Current resist compositions face challenges in achieving high sensitivity, resolution, and minimal edge roughness for fine pattern formation in microelectronic devices, particularly as feature sizes reduce, due to issues with acid diffusion and sensitivity loss at higher accelerating voltages in electron beam exposure systems.
Innovation Solution
A chemically amplified resist composition is developed using a polymer with recurring units having oxazolidinedione, thioxooxazolidinone, thiazolidinedione, or thioxothiazolidinone structures, combined with carboxyl or phenolic hydroxyl groups substituted with acid labile groups, which effectively suppresses acid diffusion and enhances dissolution contrast, leading to high sensitivity and resolution with reduced edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemically amplified resist compositions are used to enhance sensitivity and contrast, then sensitivity is improved, but acid diffusion causes image blur and resolution degradation
Solution Approach 1:
The patent introduces a basic compound as an intermediary substance that interacts with the acid generated during exposure. This basic compound suppresses acid diffusion by neutralizing or binding the acid, thereby preventing image blur while allowing the chemically amplified resist to maintain its high sensitivity and contrast properties
Solution Approach 2:
The patent changes the chemical parameters of the resist composition by adding specific basic compounds with controlled concentrations and properties. This parameter change allows the system to achieve both high sensitivity (through chemical amplification) and high resolution (through suppressed acid diffusion) simultaneously
2Manufacturing precision
If post-exposure bake temperature and time are reduced to minimize acid diffusion, then resolution is improved, but sensitivity and contrast are drastically reduced
Solution Approach 1:
The basic compound acts as a mediator that allows the decoupling of resolution improvement from sensitivity loss. By suppressing acid diffusion chemically rather than relying solely on reduced thermal energy, the system can maintain lower bake temperatures without sacrificing sensitivity or contrast
3Manufacturing precision
If accelerating voltage is increased to improve resolution and dimensional control, then edge roughness is reduced, but resist film sensitivity is lowered
Solution Approach 1:
The patent changes the chemical composition parameters of the resist film by incorporating basic compounds, which enables the system to maintain high sensitivity even at higher accelerating voltages. This compositional change allows electrons to pass through while still achieving good dimensional control through suppressed acid diffusion
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 resist composition achieves high sensitivity, full suppression of acid diffusion, and minimal edge roughness, making it suitable for fine pattern formation in VLSIs and photomasks, with improved process adaptability and pattern profile quality.
Implementation Method 1
chemically amplified resist compositions are designed such that sensitivity and contrast are enhanced by acid diffusion
Implementation Method 2
not only an improvement In dissolution contrast is important as previously reported, but control of acid diffusion is also important
Data Source
AI summary
A resist composition is provided comprising a polymer comprising recurring units (a) having an oxazolidinedione, thioxooxazolidinone, thiazolidinedione or thioxothiazolidinone structure and recurring unit (b1) having an acid labile group-substituted carboxyl group and/or recurring units (b2) having an acid labile group-substituted phenolic hydroxyl group. The resist composition suppresses acid diffusion, exhibits a high resolution, and forms a pattern of satisfactory profile with low edge roughness.