Resist Composition with Homoadamantane Resin for Micropatterning
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Solution Overview
Problem
Current resist compositions for microelectronic device lithography, particularly those using ArF immersion lithography and EUV, face challenges in achieving further miniaturization due to limitations in resolution and pattern profile stability, with acid diffusion during post-exposure bake leading to changes in critical dimension (CD) and depth of focus (DOF).
Innovation Solution
A resist composition incorporating a base resin with a polycyclic lactone structure containing a homoadamantane skeleton and a specific photoacid generator, which suppresses acid diffusion and maintains CD uniformity, is developed. This composition includes recurring units with acid labile groups and a photoacid generator capable of controlling acid diffusion during the organic solvent development process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional base resins are used in resist compositions, then manufacturing process is simpler, but resolution and pattern profile stability deteriorate
Solution Approach 1:
The base resin is segmented into multiple functional units: polycyclic lactone units (for adhesion and acid diffusion control), sultone units (for dissolution contrast), and aromatic carboxylic acid units (for chemical amplification). This segmentation allows each unit to contribute specifically to resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The invention uses a composite resin system combining polycyclic lactone, sultone, and aromatic carboxylic acid units in specific proportions. This composite approach achieves high resolution and pattern stability without requiring overly complex single-structure resins, thus balancing manufacturing precision with manageable device complexity.
2Manufacturing precision
If acid diffusion is allowed during post-exposure bake, then pattern formation is simplified, but critical dimension uniformity deteriorates
Solution Approach 1:
The polycyclic lactone units specifically control the diffusion parameter of acid during post-exposure bake by creating a glassy matrix that restricts acid mobility. This parameter control maintains critical dimension uniformity while still allowing the pattern formation process to proceed effectively.
Solution Approach 2:
The polycyclic lactone structure acts as an intermediary medium that mediates between the generated acid and the polymer matrix. It controls acid diffusion pathways, preventing excessive acid spread that would compromise critical dimension uniformity while maintaining processability.
3Manufacturing precision
If conventional photoacid generators are used, then cost is reduced, but acid diffusion control and CD uniformity deteriorate
Solution Approach 1:
The photoacid generator is selected to provide localized acid generation with controlled diffusion characteristics. The specific PAG structure ensures acid is generated at the intended location and diffuses only to the extent needed for pattern formation, improving CD uniformity without requiring excessive amounts of expensive materials.
4Area of moving object
If miniaturization is pursued, then integration density increases, but pattern profile stability and DOF margin deteriorate
Solution Approach 1:
The resist composition parameters are optimized for miniaturization: the polycyclic lactone/sultone/aromatic carboxylic acid unit combination provides appropriate glass transition temperature, solubility, and acid diffusion characteristics that maintain pattern profile stability even at reduced feature sizes, thus preserving reliability during miniaturization.
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 improved depth of focus margin, critical dimension uniformity, and minimal CD change during post-exposure bake, enabling precise micropatterning and maintaining pattern profile stability, especially for hole patterns.
Implementation Method 1
a photoacid generator containing at least one compound selected from the formulae (B-1) and (B-2)
Implementation Method 2
recurring units having an acid labile group
Data Source
AI summary
A polymer comprising units having a highly fused homoadamantane skeleton at side chain end bonded to the polymer backbone via a linking group has an appropriate solvent solubility and is capable of suppressing acid diffusion. A resist composition comprising the polymer and a specific photoacid generator exhibits a good DOF margin, CD uniformity, and a minimal CD change during PPD, and is quite effective in precise micropatterning.