Resist Top Coat for EUV Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the patterning process for semiconductor devices, especially in EUV lithography, there is a need for a resist top coat composition that reduces the effect of contaminants, shields against out-of-band (OOB) light, minimizes film loss, and enhances resist sensitivity while maintaining resolution and edge roughness, which is challenging due to the high sensitivity and low light intensity of EUV exposure.
Innovation Solution
A resist top coat composition is developed using a polymer with a repeating unit of styrene having a 1,1,1,3,3,3-hexafluoro-2-propanol group, which is soluble in organic solvents, allowing for simultaneous development and removal, thereby reducing film loss and bridging between patterns, and effectively absorbing OOB light to protect the resist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sensitivity of the resist is enhanced to acquire throughput with low light intensity in EUV lithography, then the throughput is improved, but the resolution and edge roughness deteriorate
Solution Approach 1:
The patent segments the resist system into two distinct components: a high-sensitivity EUV resist base film and a separate top coat layer. The top coat, made from a polymer with repeating units of formula (1) containing fluorinated groups, is specifically designed to protect the resist while being removable by organic solvent developers. This segmentation allows the base resist to be highly sensitive for throughput while the top coat maintains resolution and edge roughness by providing protective functionality that can be selectively removed.
2Reliability
If a top coat is formed on the resist upper layer to prevent contaminant effects, then environmental resistance is improved, but the process complexity increases
Solution Approach 1:
The patent merges the top coat removal step with the resist development step by using an organic solvent developer that simultaneously removes both the top coat and develops the resist pattern. The polymer with repeating units of formula (1) is specifically designed to be soluble in organic solvents, allowing the top coat to be removed together with the resist in a single development process, thereby reducing process complexity while maintaining environmental resistance.
3Productivity
If the amount of amine quencher is reduced in EUV resist, then the resist sensitivity is improved, but the T-top shape formation increases due to amine contamination
Solution Approach 1:
The patent introduces the top coat layer as an intermediary barrier between the resist base film and the contaminated atmosphere. The top coat, formed from the polymer with repeating units of formula (1), protects the underlying resist from amine contamination in the air, allowing the resist to maintain low amine quencher content for high sensitivity while preventing T-top shape formation through the protective top coat layer.
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 composition enhances resist sensitivity, suppresses outgas emission, and maintains pattern integrity by preventing film loss and bridging, while effectively blocking OOB light, thus improving the overall patterning process efficiency and throughput.
Implementation Method 1
effectively absorbing OOB light to protect the resist
Implementation Method 2
The formation of a top coat on a resist's upperlayer is effective in preventing the effect of contaminants in the surrounding atmosphere
Implementation Method 3
the resist top coat composition used in the patterning process contains a polymer having a repeating unit of styrene having a 1,1,1,3,3,3-hexafluoro-2-propanol group which is soluble in an organic-solvent-based developer
Data Source
AI summary
There is provided a patterning process that forms a negative pattern by developing using an organic solvent, using a resist top coat composition that not only reduces the effect from the environment on a resist film and effectively blocks OOB light, but also reduces the film loss of a resist pattern and the bridging between patterns, enhances the sensitivity of the resist film, and suppresses the emission of an outgas from the resist film. The patterning process includes the steps of forming a resist top coat on a photoresist film formed on a substrate, with the resist top coat using as a top base material a polymer having a repeating unit p of styrene having a 1,1,1,3,3,3-hexafluoro-2-propanol group, in which m is 1 or 2, and p is 0<p≦1.0; performing EUV exposure using an electron beam or having a wavelength of 3 nm to 15 nm; and forming a negative pattern by developing using an organic-solvent-based developer.