Metal-Containing Resist Composition for EUV Lithography
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Solution Overview
Problem
Current chemically amplified (CA) photoresists face challenges in achieving high resolution and low line edge roughness (LER) for next-generation semiconductor devices, particularly under EUV exposure, due to intrinsic image blurring and reduced sensitivity.
Innovation Solution
A method of forming patterns using a metal-containing resist composition, which involves coating, heat treatment, exposure to extreme ultraviolet light, and development, resulting in a resist pattern with improved surface roughness and resolution. The metal compound in the resist composition includes organooxy or organocarbonyloxy group-containing tin compounds, optimizing the resist layer's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If chemically amplified (CA) photoresists are used to achieve high sensitivity, then photospeed is improved, but line edge roughness (LER) increases and resolution deteriorates
Solution Approach 1:
The patent changes the fundamental chemical composition parameters of the photoresist by replacing traditional CA photoresist chemistry with organometallic-based chemistry. Specifically, it uses organotin compounds (Sn) with peroxo complexes as photoactive species, which fundamentally alters the photosensitivity mechanism and eliminates the acid-catalyzed amplification process that causes LER, while maintaining high photospeed through direct photochemical reactions.
Solution Approach 2:
The patent employs composite material design by combining organometallic compounds (organotin with peroxo groups) with specific resin matrices and additives. This composite approach integrates the high EUV absorption of metal compounds with the processability and film-forming properties of organic resins, achieving both high sensitivity and low LER characteristics.
2Use of energy by moving object
If chemically amplified (CA) photoresists are used for pattern formation, then sensitivity is improved, but intrinsic image blurring occurs and resolution decreases
Solution Approach 1:
The patent extracts and removes the problematic acid-catalyzed amplification mechanism from the photoresist system. By eliminating the chemical amplification step that causes intrinsic image blurring, the system directly converts absorbed EUV energy into photochemical changes, preserving the spatial fidelity of the exposure pattern and achieving high resolution while maintaining sensitivity.
Solution Approach 2:
The patent substitutes the chemical amplification mechanism (mechanism-based on acid diffusion and catalysis) with a direct photochemical mechanism. The organometallic compounds undergo direct photoinduced decomposition or isomerization upon EUV absorption, replacing the multi-step chemical amplification process with a more direct energy-to-change conversion that minimizes image blurring.
3Manufacturing precision
If inorganic photosensitive compositions are used to achieve low line edge roughness, then LER is reduced, but chemical modification through nonchemical amplification mechanism limits versatility
Solution Approach 1:
The patent changes the chemical nature of the photoresist from purely inorganic or simple organic systems to sophisticated organometallic compositions. The organotin compounds with peroxo groups provide a unique chemical system that combines the low LER benefits of inorganic-based materials with the tunability and processability of organic compounds, enabling versatile patterning applications.
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 method achieves excellent resolution and reduced line edge roughness, enhancing the performance of the photoresist in EUV lithography and addressing the limitations of traditional CA photoresists.
Implementation Method 1
exposing a metal-containing resist layer using extreme ultraviolet light, light having a wavelength of about 5 nm to about 50 nm
Data Source
AI summary
Disclosed is a method of forming patterns including coating a metal-containing resist composition on a substrate; a heat treatment including drying and heating to form a metal-containing resist layer on the substrate; exposing a metal-containing resist layer using a patterned mask; and developing including coating a developer composition to remove unexposed regions to form a resist pattern, wherein the coating the metal-containing resist composition is performed by coating the metal-containing resist composition with a spin coater at a speed of about 100 to about 1,500 rpm for about 60 to about 120 seconds, the heating is performed at a temperature of about 90 to about 200° C. for about 30 to about 120 seconds, the exposing the metal-containing resist layer is performed by irradiating extreme ultraviolet light, light having a wavelength of about 5 nm to about 50 nm, or a combination thereof.