Negative Resist Composition for Sub-50 nm Lithography
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Solution Overview
Problem
Current negative resist compositions for semiconductor manufacturing, particularly in EB lithography, face challenges in achieving high resolution and low defect formation, especially for sub-50 nm patterns, with existing compositions exhibiting pattern density dependence and radial defects during development.
Innovation Solution
A negative tone resist composition incorporating a polymer with recurring units having at least two acid-eliminatable hydroxyl or alkoxy groups, which minimizes defect formation by ensuring high resolution and low line edge roughness, achieved through specific partial structures and acid-catalyzed crosslinking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional negative resist compositions are used for sub-50 nm patterning, then high resolution is achieved, but radial defects and pattern density dependence occur during development
Solution Approach 1:
The patent modifies the chemical composition parameters of the resist system by introducing a specific base polymer with hydroxyl groups and combining it with a polybasic acid crosslinker. This parameter change in the chemical formulation enables simultaneous achievement of high resolution and reduced radial defects by optimizing the crosslinking density and distribution in the resist film.
Solution Approach 2:
The invention creates a composite resist system combining a base polymer containing hydroxyl groups with a polybasic acid crosslinker. This composite material approach allows the synergistic effect of the base polymer providing solubility and the crosslinker providing structural integrity, thereby achieving high resolution patterns with minimal radial defects during development.
2Manufacturing precision
If crosslinking is enhanced to improve pattern density dependence, then manufacturing precision improves, but defect formation increases
Solution Approach 1:
The patent optimizes the crosslinking parameters by selecting a polybasic acid crosslinker with specific basicity and functionality. This parameter optimization ensures sufficient crosslinking to improve pattern density dependence while controlling the crosslinking kinetics to prevent excessive crosslinking that would cause radial defects.
Solution Approach 2:
The invention employs a self-regulating crosslinking mechanism where the polybasic acid crosslinker reacts selectively with hydroxyl groups in the base polymer. The feedback control is achieved through the inherent selectivity and stoichiometry of the crosslinking reaction, which automatically adjusts crosslinking density to improve pattern density dependence without causing harmful radial defects.
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 proposed resist composition effectively forms resist patterns with high resolution corresponding to sub-50 nm sizes and minimal defects, enhancing the yield of semiconductor devices by reducing radial defects and pattern density dependence.
Implementation Method 1
an acid generator which is decomposed to generate an acid upon exposure to radiation
Implementation Method 2
a crosslinker which forms crosslinks between polymer molecules under the catalysis of the acid
Implementation Method 3
a basic compound for controlling diffusion of the acid generated upon exposure
Data Source
AI summary
A negative resist composition comprising a polymer comprising recurring units having at least two acid-eliminatable hydroxyl or alkoxy groups in the molecule is effective for forming a resist pattern having a high resolution and minimal LER while minimizing defects.