O-Arenesulfonyloxime Photoacid Generators for Deep UV Lithography
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Solution Overview
Problem
Current photoacid generators for chemically amplified resist compositions face challenges in achieving high resolution and pattern profile control, especially when the resist film thickness is reduced, leading to issues like poor compatibility with resins, low solubility, and unsatisfactory pattern formation on highly reflective substrates.
Innovation Solution
A chemically amplified resist composition incorporating an O-arenesulfonyloxime compound with specific structural features, such as the general formula (1), which acts as a photoacid generator, enhancing dissolution, storage stability, and pattern profile shape, particularly at reduced film thickness, and is suitable for deep UV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photoacid generators are used in chemically amplified resist compositions, then the resist can be processed, but high resolution and pattern profile control are not achieved, especially when resist film thickness is reduced
Solution Approach 1:
The patent modifies the molecular structure of photoacid generators by introducing specific substituents (fluorine atoms, alkyl groups, alkoxy groups) at defined positions on the aromatic ring. These parameter changes in molecular structure enhance the generator's ability to control pattern profiles while maintaining compatibility with reduced resist film thicknesses, directly resolving the contradiction between manufacturing precision and device complexity.
Solution Approach 2:
The patent creates a composite system by combining the specially structured photoacid generator with specific resin components (phenolic resins, polyhydroxystyrene) and solvents. This composite material approach enables high resolution and pattern profile control in thin film applications, as the synergistic interaction between components addresses both the precision and thickness challenges simultaneously.
2Manufacturing precision
If photoacid generators are used to achieve high resolution, then pattern definition improves, but compatibility with resins and solubility deteriorate
Solution Approach 1:
The patent systematically varies parameters of the photoacid generator structure including the type of substituent (fluorine, alkyl, alkoxy), the number of substituents (r=0 to 4), and the position of substitution (r′=0 to 5). These parameter adjustments optimize both resolution performance and resin compatibility, allowing the generator to function effectively across different resin systems without sacrificing solubility or pattern definition.
3Length of moving object
If resist film thickness is reduced to achieve finer patterns, then pattern rule decreases, but pattern profile shape and line width variation worsen
Solution Approach 1:
The patent introduces fluorine atoms at specific positions (r and r′ values) on the aromatic ring of the photoacid generator. This parameter change in molecular structure enhances the generator's performance in thin film applications, enabling it to maintain consistent line width and profile shape even when resist film thickness is reduced for finer pattern rules, thereby resolving the contradiction between pattern miniaturization and manufacturing precision.
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 achieves high resolution and improved pattern profile shape with minimized line width variation and shape degradation during long-term processing, suitable for microfabrication, especially when processed by deep UV lithography.
Implementation Method 1
a compound capable of generating an acid upon exposure to radiation (referred to as 'photoacid generator')
Implementation Method 2
a resin and/or compound in which an alkali-soluble phenol or carboxylic acid is partially or entirely protected with acid labile protective groups (commonly referred to as 'acid labile groups') is catalytically decomposed with the acid generated upon exposure
Implementation Method 3
a resin and/or compound having an alkali-soluble phenol or carboxylic acid and a compound capable of bonding or crosslinking said resin or compound under the action of an acid (referred to as 'acid crosslinker') are crosslinked with the acid generated upon exposure
Implementation Method 4
applying the resist solution onto a substrate by a variety of methods, and evaporating off the solvent optionally by heating
Data Source
AI summary
A photoacid generator has formula (1) wherein R is H, F, Cl, nitro, alkyl or alkoxy, n is 0 or 1, m is 1 or 2, r is an integer of 0-4, and r′ is an integer of 0-5. A chemically amplified resist composition comprising the photoacid generator has advantages including a high resolution, focus latitude, long-term PED dimensional stability, and a satisfactory pattern profile shape. When the photoacid generator is combined with a resin having acid labile groups other than those of the acetal type, resolution and top loss are improved. The composition is suited for deep UV lithography.