Alkyltin-Oxo Cage Photoresist for EUV Resolution
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Solution Overview
Problem
Existing resist compositions for EUV lithography face challenges in achieving acceptable resolution, line-edge roughness, and sensitivity, with chemically amplified resists (CARs) having stochastic nature and metal oxide nanoclusters being negative tone materials with moderate sensitivity.
Innovation Solution
The use of alkyltin-oxo cages with large non-nucleophilic counterions such as tetrakis(pentafluorophenyl) borate provides a positive tone resist composition with high sensitivity, utilizing the high EUV absorbance of fluorine atoms and large borate counterions to achieve improved resolution and reduced chemical noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemically amplified resists (CARs) are used for EUV lithography, then the resist can form patterns through photo-acid generator decomposition, but the stochastic nature of the process results in poor resolution and high line-edge roughness
Solution Approach 1:
The patent changes the fundamental mechanism parameter from stochastic photo-acid generator decomposition to deterministic metal oxide nanocluster aggregation. By altering the chemical composition and reaction pathway, the process achieves deterministic pattern formation with reduced stochasticity, improving both resolution and line-edge roughness
Solution Approach 2:
The patent uses composite metal oxide nanoclusters with organic ligands as the resist material. This composite structure combines the high EUV absorption cross-section of metal oxides with the solubility control provided by organic ligands, enabling superior patterning performance compared to conventional polymer-based CARs
2Use of energy by moving object
If metal oxide nanoclusters are used as resist material, then the EUV absorption cross-section is larger requiring less exposure power, but the material acts as negative tone resist with only moderate sensitivity
Solution Approach 1:
The patent modifies the chemical parameters of metal oxide nanoclusters by selecting specific metal oxides (SnO2, TiO2, ZrO2, HfO2) and controlling their size (5-50 nm), to optimize both the EUV absorption cross-section and the sensitivity of the resist response to exposure
Solution Approach 2:
The patent introduces organic ligands as intermediaries that mediate between the metal oxide nanoclusters and the developer solution. These ligands control the solubility behavior and enhance the sensitivity of the resist to exposure while maintaining the high absorption cross-section of the metal oxide core
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 alkyltin-oxo cage resist compositions exhibit high sensitivity and reduced chemical noise, enabling the formation of small features with improved line-edge roughness and throughput in lithographic processes.
Implementation Method 1
The metal oxide nanoparticles have larger EUV absorption cross-sections than carbon atoms in CAR and thus there is a greater likelihood of EUV photons being absorbed
Implementation Method 2
Upon EUV exposure, photons are absorbed by the nanoparticles or nanoclusters and this leads to the generation of secondary electrons
Implementation Method 3
The electrons break the bonds between the ligands and the nanoparticles or nanoclusters. This allows the nanoparticles or nanoclusters to cluster together and hence changes the solubility of the resist
Implementation Method 4
The electrons generated excite photo-acid generators (PAG) which subsequently decompose and can catalyse a deblocking reaction, which leads to a change in the solubility of the CAR
Implementation Method 5
The photo-acid generators (PAG) which subsequently decompose and can catalyse a deblocking reaction
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
A resist composition for use in the fabrication of integrated circuits, the use of a resist composition, and a lithographic method utilising a resist composition, wherein the resist composition comprises an alkyltin-oxo cage having a counterion selected from tetrakis(pentafluorophenyl) borate, tetrakis[3,5-bis(trifluoromethyl)phenyl]borate, tetrakis[3,5-bis(tert-butyl)phenyl]borate, and tetrakis[(3,5-bis(l,l,l,3,3,3-hexafluoro-2-methoxypropan-2-yl)phenyl)phenyl]borate. A lithographic method comprising the steps of: a) providing a resist composition comprising an alkyltin-oxo cage having a counterion selected from the above borate groups; b) exposing the resist composition to a patterned radiation beam or an electron beam to form a pattern in the resist composition; and c) developing the resist to form a circuit pattern.