EUV Resist Composition with Nitro-Substituted Linker for LWR Control
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Solution Overview
Problem
Current EUV resist materials face challenges in achieving high sensitivity while maintaining low line width roughness (LWR) and critical dimension uniformity (CDU) due to the tradeoff between sensitivity and acid diffusion, with existing compositions either improving one at the expense of the other.
Innovation Solution
A resist composition featuring a polymer with repeat units derived from sulfonium or iodonium salts containing a polymerizable unsaturated bond and a fluorosulfonic acid site, incorporating a nitro-substituted benzene ring to control acid diffusion and enhance sensitivity through self-sensitization during EUV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the acid diffusion distance is reduced to improve LWR or CDU, then sensitivity becomes lower
Solution Approach 1:
The acid generator is segmented into two functional parts: a sulfonium or iodonium salt moiety that generates acid upon EUV exposure, and a separate fluorosulfonic acid site that acts as a diffusion barrier. This segmentation allows the acid generation function and acid diffusion control function to operate independently, resolving the contradiction between limiting acid diffusion (for low LWR) and maintaining sensitivity.
Solution Approach 2:
The fluorosulfonic acid site serves as an intermediary component between the acid generation site and the polymer backbone. It mediates the acid diffusion process by providing a controlled pathway that limits acid spread while still allowing sufficient acid to reach the necessary regions for pattern formation, thereby maintaining sensitivity without compromising LWR.
2Manufacturing precision
If the PEB temperature is lowered to improve LWR or CDU, then sensitivity becomes lower
Solution Approach 1:
The invention changes the chemical parameters of the acid generator system by incorporating fluorosulfonic acid sites with specific pKa values. This parameter change allows the system to achieve effective acid diffusion control at lower PEB temperatures while maintaining sensitivity, because the fluorosulfonic acid sites provide thermodynamic control over acid diffusion rather than relying solely on kinetic control through temperature.
3Manufacturing precision
If the amount of quencher added is increased to improve LWR or CDU, then sensitivity becomes lower
Solution Approach 1:
The invention extracts the acid diffusion control function from the quencher component and assigns it to the fluorosulfonic acid sites within the polymer structure. This extraction eliminates the need to add separate quenchers in large amounts, as the fluorosulfonic acid sites inherently provide the necessary diffusion control, thereby maintaining sensitivity while achieving low LWR.
4Manufacturing precision
If a polymer-bound acid generator is used to suppress acid diffusion, then LWR is improved but sensitivity control is insufficient
Solution Approach 1:
The invention creates a composite acid generator structure combining a sulfonium or iodonium salt with a fluorosulfonic acid site within the same polymer repeat unit. This composite structure integrates both acid generation capability and acid diffusion control in a single molecular entity, achieving both high sensitivity and low LWR simultaneously.
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 and improved LWR/CDU by controlling acid diffusion and promoting efficient acid generation, maintaining resolution without image blurs, and functioning effectively in both positive and negative tone pattern formation.
Implementation Method 1
an acid generator capable of generating a sulfonic acid bound to a polymer backbone upon light exposure
Implementation Method 2
having a nitro-substituted benzene ring in a linker between the polymerizable unsaturated bond and the fluorosulfonic acid site
Data Source
AI summary
A resist composition comprising a polymer is provided, the polymer comprising repeat units derived from a sulfonium or iodonium salt having a nitro-substituted benzene ring in a linker between a polymerizable unsaturated bond and a fluorosulfonic acid site. The resist composition has a high sensitivity and forms a pattern with improved LWR or CDU, independent of whether it is of positive or negative tone.