Crosslinkable EUV Photoresist for Low-Roughness Patterning
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Solution Overview
Problem
As critical dimensions in integrated circuits shrink, the ability of photoresists to perfectly replicate photomask features is challenged by image blur due to photoacid diffusion, leading to reduced resolution and increased line width roughness.
Innovation Solution
Development of crosslinkable photoresist polymers with halogenated functional groups that covalently bond to polymer sidechains, increasing glass transition temperatures to restrict photoacid diffusion and enhance dimensional stability, thereby improving pattern quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist is used for lithography, then pattern transfer is enabled, but photoacid diffusion causes image blur and reduced resolution
Solution Approach 1:
The patent changes the chemical parameters of the photoresist by incorporating polymers with specific glass transition temperatures (Tg > 100°C, preferably Tg > 140°C) and incorporating crosslinking agents. These parameter changes restrict photoacid diffusion and improve pattern resolution without sacrificing other critical properties.
Solution Approach 2:
The patent uses composite photoresist formulations combining polymers with high glass transition temperatures, crosslinking agents, and photoactive compounds. This composite approach creates a material that simultaneously achieves dimensional stability, controlled crosslinking, and effective pattern transfer while minimizing photoacid diffusion.
2Productivity
If critical dimensions are reduced for scaling, then production efficiency increases, but line width roughness increases
Solution Approach 1:
The patent changes the thermal and chemical parameters of the photoresist system by using polymers with elevated glass transition temperatures and incorporating crosslinking mechanisms. These changes reduce line width roughness and improve pattern quality even at reduced critical dimensions, enabling continued scaling while maintaining manufacturing precision.
3Manufacturing precision
If polymer glass transition temperature is increased to restrict photoacid diffusion, then pattern quality improves, but polymer selection and processing become more limited
Solution Approach 1:
The patent applies local quality by incorporating crosslinking agents at specific concentrations (0.1-50 wt%, preferably 1-20 wt%) within the photoresist formulation. This localized approach allows the use of polymers with elevated Tg while maintaining processability and enabling pattern transfer, as the crosslinking occurs specifically in response to photolysis rather than requiring fundamentally different polymer chemistry.
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 solution provides higher resolution and reduced line width roughness, enhancing the yield and reliability of semiconductor devices by improving resist pattern quality.
Implementation Method 1
the polymer reacts with the crosslinker to form a crosslinked polymer
Implementation Method 2
exposing the photoresist layer to an extreme ultraviolet (EUV) radiation, heating the photoresist layer, during which the polymer reacts with the crosslinker to form a crosslinked polymer
Data Source
AI summary
A method for forming a semiconductor device is provided. The method includes forming a photoresist layer over a substrate, exposing the photoresist layer to radiation to form a pattern therein, and selectively removing portions of the photoresist layer that are not exposed to the radiation to form a patterned photoresist layer. The photoresist layer comprises a fluorine-containing polymer, a crosslinker and a photoactive compound.