Hypervalent Iodine Resist Composition for EUV Lithography
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Solution Overview
Problem
Current resist compositions face challenges in achieving high sensitivity and resolution, especially in EUV lithography, due to issues like acid diffusion, edge roughness, and the influence of shot noise, which affect the formation of small pattern features and lead to defects such as electric conduction failures.
Innovation Solution
A resist composition comprising a hypervalent iodine compound and a carboxy group-containing polymer, which exhibits high sensitivity and resolution when processed by high-energy radiation, such as EB and EUV lithography, and forms a resist film suitable for precise micropatterning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemically amplified resist composition is used to enhance sensitivity and contrast through acid diffusion, then sensitivity and contrast are improved, but acid diffusion causes image blur and prevents formation of patterns at 16 nm et seq. processing dimension
Solution Approach 1:
The patent extracts and eliminates the acid diffusion mechanism from the resist composition by using a non-chemically amplified system. Instead of relying on acid-catalyzed deprotection reactions, the invention uses direct photochemical or electron beam-induced scission of the polymer chains to change solubility, thereby removing the harmful acid diffusion effect while maintaining sensitivity enhancement through alternative mechanisms.
Solution Approach 2:
The patent changes the fundamental chemical mechanism from chemically amplified (acid-mediated) to non-chemically amplified (direct bond scission). This parameter change in the reaction mechanism eliminates acid diffusion while maintaining the ability to achieve high sensitivity through direct molecular weight reduction upon exposure, enabling pattern formation at 16 nm and below without image blur.
2Manufacturing precision
If negative resist materials like HSQ or chlorine-substituted calixarene are used to avoid acid diffusion blur, then edge roughness is reduced and resolution is improved, but sensitivity is insufficient
Solution Approach 1:
The patent employs composite material design by combining specific polymer structures with carefully selected additives and solvents. The resist composition includes a polymer with specific functional groups that, when exposed, undergo controlled molecular weight reduction. This composite approach achieves both low edge roughness (through minimal diffusion) and high sensitivity (through efficient photochemical or EB-induced scission), overcoming the limitations of pure HSQ or calixarene systems.
Solution Approach 2:
The patent changes the sensitivity mechanism from relying on crosslinking density (as in HSQ) to relying on controlled molecular weight reduction through direct bond scission. This parameter change enables higher sensitivity by reducing the number of photons or electrons required to achieve the necessary solubility change, while maintaining low edge roughness through the non-diffusive nature of the reaction.
3Manufacturing precision
If PMMA or HSQ based resist composition is used to achieve high resolution, then shot noise influence is reduced, but sensitivity is largely affected by stochastics and desired resolution is not achieved
Solution Approach 1:
The patent changes the photochemical efficiency parameter by using polymers with higher absorption coefficients and more efficient scission mechanisms. This increases the probability of successful pattern formation per incident photon or electron, thereby reducing the impact of shot noise statistics. The modified resist composition achieves better sensitivity while maintaining pattern uniformity through controlled molecular weight reduction rather than relying on stochastic crosslinking processes.
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 resist composition achieves high sensitivity and resolution, reducing shot noise and line edge roughness, enabling the formation of small-sized patterns without image blur, and eliminates the need for metal elements, thus avoiding solubility and stability issues associated with metal resist compositions.
Implementation Method 1
As the means for reducing the influence of shot noise on the resist side, it is noteworthy to incorporate an element having high EUV absorption
Implementation Method 2
exposing the resist film to an electron beam (EB) or an extreme ultraviolet radiation (EUV)
Implementation Method 3
a carboxy group-containing polymer, which exhibits high sensitivity and resolution when processed by high-energy radiation
Data Source
AI summary
A resist composition is provided that comprises a hypervalent iodine compound having the formula (1), a carboxy group-containing polymer, and a solvent. In formula (1), n is an integer of 0 to 5, R1 and R2 are each independently halogen or a C1-C10 hydrocarbyl group which may contain a heteroatom, R1 and R2 may bond together to form a ring with the carbon atoms to which they are attached and the intervenient atoms. R3 is halogen or a C1-C40 hydrocarbyl group which may contain a heteroatom.