Hypervalent Iodine Resist Composition for EUV Resolution
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Solution Overview
Problem
Existing resist compositions face challenges in achieving high contrast, maximum resolution, and satisfactory sensitivity for fine pattern formation in microelectronic devices, particularly at the 3-nm and 2-nm node levels, due to issues with acid diffusion and pattern defects such as bridges and scum formation.
Innovation Solution
A resist composition comprising a base polymer with repeat units having an acid labile group and carboxy group, combined with a hypervalent iodine compound, an organic solvent, and optionally a photoacid generator and quencher, enhances contrast and resolution, particularly under high-energy radiation like electron beam and EUV lithography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid diffusion is controlled by reducing temperature and/or time of post exposure bake (PEB), then resolution for fine patterns is improved, but sensitivity and contrast are drastically reduced
Solution Approach 1:
The invention changes the chemical parameters of the resist system by introducing a polymer-bound acid generator with specific molecular weight and structure, and adjusting the PEB temperature to 80°C or higher, to achieve simultaneous improvement in resolution and maintenance of sensitivity/contrast
Solution Approach 2:
The invention uses a composite resist composition comprising a base polymer, a polymer-bound acid generator with specific properties (number-average molecular weight 10,000-100,000, acid generation units at 0.1-10 mmol/g), and optional additives, creating a synergistic system that resolves the contradiction between resolution and sensitivity
2Manufacturing precision
If an acid generator capable of generating bulky acid is added to control acid diffusion, then resolution is improved, but the resist composition complexity increases
Solution Approach 1:
The invention extracts the acid generator function from separate small-molecule additives and integrates it into the polymer structure itself through polymer-bound acid generators, simplifying the overall composition while maintaining resolution benefits
Solution Approach 2:
The polymer-bound acid generator serves multiple functions simultaneously: it acts as both the polymer matrix component and the acid generation source, reducing the number of separate components needed while achieving effective acid diffusion control
3Reliability
If crosslinking is used to increase molecular weight and improve contrast, then pattern definition is enhanced, but polymer particle agglomeration occurs during storage leading to defects
Solution Approach 1:
The invention performs preliminary crosslinking during the PEB process at controlled temperatures (80°C or higher) before development, achieving the desired contrast enhancement while preventing premature agglomeration that would occur with pre-crosslinked resists during storage
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 contrast, improved maximum resolution, and reduced line width roughness (LWR), enabling precise micropatterning with reduced defects.
Implementation Method 1
a resist composition comprising (A) a base polymer containing a polymer comprising repeat units having an acid labile group and repeat units having a carboxy group, (B) an organic solvent, and (C) a hypervalent iodine compound
Implementation Method 2
a base polymer containing a polymer comprising repeat units having an acid labile group
Data Source
AI summary
The resist composition exhibits a high contrast, improved maximum resolution, and satisfactory sensitivity and line width roughness (LWR) when processed by lithography using high-energy radiation, especially electron beam (EB) and EUV, and a pattern forming process using the resist composition. The resist composition comprising (A) a base polymer containing a polymer comprising repeat units having an acid labile group and repeat units having a carboxy group, (B) an organic solvent, and (C) a hypervalent iodine compound having formula (1):