BARC Interface Layer for EUV Photoresist Adhesion
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Solution Overview
Problem
In extreme ultraviolet (EUV) lithography, existing photoresist and bottom anti-reflective coating (BARC) technologies face issues such as photoresist collapsing, peeling, and scum formation due to high aspect ratios and poor adhesion, which degrade imaging resolution and manufacturing efficiency.
Innovation Solution
A lithography method involving a BARC layer with organic polymers bonded to fluoro-containing photoacid generators and chelating ligands or capping monomers, combined with a metal-containing photoresist layer, forms an interface layer to enhance adhesion and reduce scum, using EUV radiation for patterning and developing a patterned photoresist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If photoresist thickness is increased to provide sufficient etch resistance, then etch resistance is improved, but imaging resolution deteriorates due to depth of focus limitations
Solution Approach 1:
The patent divides the photoresist system into multiple layers (first photoresist layer and second photoresist layer) with different functions. The first layer provides etch resistance while the second layer enables high-resolution patterning, resolving the contradiction between thickness requirements and imaging quality.
Solution Approach 2:
The patent uses composite photoresist materials with specific compositions (including metal-containing photoresist and organic polymer photoresist) that provide both sufficient thickness for etch resistance and appropriate optical properties for high-resolution EUV lithography patterning.
2Manufacturing precision
If photoresist thickness is scaled down to match smaller feature sizes, then imaging resolution is improved, but etch resistance becomes insufficient
Solution Approach 1:
The patent segments the photoresist into two layers where the first layer (thicker) provides etch resistance and the second layer (thinner) provides imaging resolution, allowing each layer to be optimized independently for its specific function.
3Ease of manufacture
If traditional i-ArF lithography is used for pitches below 20 nm, then manufacturing cost is reduced, but resolution targets cannot be met
Solution Approach 1:
The patent changes the lithography wavelength parameter from conventional i-ArF (193 nm) to EUV (13.5 nm), enabling resolution of sub-20 nm pitches while maintaining manufacturing feasibility through the developed multi-layer photoresist system and process optimization.
4Manufacturing precision
If EUV lithography is implemented to achieve sub-20 nm resolution, then imaging resolution is improved, but photoresist stability deteriorates due to scum and collapsing
Solution Approach 1:
The patent employs composite photoresist materials containing metal nanoparticles dispersed in organic polymer matrices, which enhance structural stability and prevent scum and collapsing during EUV lithography processing while maintaining high resolution capability.
Solution Approach 2:
The patent applies preliminary treatments including spin coating to form uniform thin films, soft baking to remove solvents, and hard baking to enhance adhesion and structural stability before exposure, preventing defects during the lithography process.
5Strength
If multiple-film photoresist is used to overcome thickness-resolution trade-off, then etch resistance and imaging resolution are both improved, but process complexity increases
Solution Approach 1:
The patent segments the photoresist into two layers with distinct compositions and functions, allowing each layer to be optimized independently while maintaining a relatively simple overall process flow that can be integrated into existing manufacturing.
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 significantly improves adhesion strength, reduces photoresist collapsing and peeling, and enhances lithography performance by forming a stable interface layer between the BARC and photoresist layers, thereby improving pattern fidelity and manufacturing efficiency.
Implementation Method 1
a lithography method involving a BARC layer with organic polymers bonded to fluoro-containing photoacid generators and chelating ligands or capping monomers, combined with a metal-containing photoresist layer, forms an interface layer to enhance adhesion
Implementation Method 2
EUV lithography employs scanners using radiation in the EUV region, having a wavelength of about 1 nm to about 100 nm
Data Source
AI summary
A lithography method includes forming a bottom anti-reflective coating (BARC) layer on a substrate, wherein the BARC layer includes an organic polymer and a reactive chemical group having at least one of chelating ligands and capping monomers, wherein the reactive chemical group is bonded to the organic polymer; coating a metal-containing photoresist (MePR) layer on the BARC layer, wherein the MePR being sensitive to an extreme ultraviolet (EUV) radiation; performing a first baking process to the MePR layer and the BARC layer, thereby reacting a metal chemical structure of the MePR layer and the reactive chemical structure of the BARC layer and forming an interface layer between the MePR layer and the BARC layer; performing an exposure process using the EUV radiation to the MePR layer; and developing the MePR layer to form a patterned photoresist layer.