Fluorinated Sulfonate Esters for EUV Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current EUV lithography resists face challenges with image blur due to gradient-driven acid diffusion, and existing photo-acid generators (PAGs) are unstable and highly diffusing, limiting their thermal and hydrolytic stability.
Innovation Solution
Development of non-ionic PAGs comprising sulfonate esters of fluoroalkyl substituted alpha-hydroxy aryl ketones, which release low-diffusing sulfonic acids and exhibit improved thermal and hydrolytic stability, suitable for use in EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ionic PAGs (triphenylsulfonium or iodonium sulfonates) are used, then photo-acid generation is effective, but acid diffusion is high causing image blur
Solution Approach 1:
The patent changes the chemical structure parameters of PAGs by introducing fluorinated sulfonate esters with specific molecular weight and structure (formula 1), which fundamentally alters the diffusion characteristics of the generated acid while maintaining photo-acid generation efficiency
Solution Approach 2:
The patent uses composite PAG structures combining fluorinated groups with sulfonate esters of alpha-hydroxy aryl ketones, creating a hybrid molecule that achieves both low diffusion and high stability properties
2Reliability
If aryl ketone PAGs with perfluoro alkyl sulfonic acids are used, then photo-acid generation is achieved, but thermal and hydrolytic stability is poor
Solution Approach 1:
The patent modifies the chemical parameters by replacing perfluoro alkyl sulfonic acids with fluorinated sulfonate esters of alpha-hydroxy aryl ketones, which have superior thermal and hydrolytic stability while maintaining photo-acid generation capability
Solution Approach 2:
The patent replaces unstable PAG components with more stable alternatives that have longer functional lifetime in resist formulations, improving overall formulation stability
3Ease of operation
If non-ionic PAGs are used, then solubility in casting solvents and homogeneous distribution are improved, but photo-acid generation efficiency must be maintained
Solution Approach 1:
The patent changes the ionic parameter of PAGs by designing non-ionic fluorinated sulfonate esters that provide both improved solubility/distribution and maintained photo-acid generation efficiency through optimized molecular structure
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 new PAGs provide enhanced stability and reduced diffusion, leading to improved resolution and reduced defects in EUV lithography, enabling the formation of precise patterns with fewer defects associated with out-of-band radiation.
Implementation Method 1
PAGs comprising sulfonate esters of fluoroalkyl substituted alpha-hydroxy aryl ketones
Implementation Method 2
gradient-driven acid diffusion
Data Source
AI summary
Non-ionic photo-acid generating (PAG) compounds were prepared that contain an aryl ketone group having a perfluorinated substituent alpha to the ketone carbonyl. The non-polymeric PAGs release a sulfonic acid when exposed to high energy radiation such as deep UV or extreme UV light. The photo-generated sulfonic acid has a low diffusion rate in an exposed resist layer subjected to a post-exposure bake (PEB) at 100° C. to 150° C., resulting in formation of good line patterns after development. At higher temperatures, the PAGs can also undergo a thermal reaction to form a sulfonic acid. The perfluorinated substituent provides improved thermal stability and hydrolytic/nucleophilic stability.