Naphthol Resist Double Patterning via High-Energy Radiation
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Solution Overview
Problem
Current double patterning processes in lithography face challenges such as reduced throughput due to double dry etchings, pattern misregistration, and the need for post-exposure bake and development steps, which complicate the process and reduce overlay accuracy, especially when trying to achieve sub-32 nm feature sizes.
Innovation Solution
A process involving a first positive resist composition with naphthol-based polymers that are crosslinked using high-energy radiation of up to 200 nm wavelength, allowing for a single dry etching step and improved overlay accuracy by forming a first resist pattern that is insoluble in alkaline developers, followed by a second resist pattern formed in the spaces of the first, reducing the pitch between patterns to half.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double dry etching is used in double patterning process, then pattern density is improved, but productivity deteriorates due to reduced throughput
Solution Approach 1:
The patent extracts and removes one of the two dry etching steps from the conventional double patterning process. By making the first resist pattern insoluble through irradiation with extreme ultraviolet light or electron beams, the need for a second dry etching step is eliminated, thereby maintaining pattern density while improving throughput and productivity.
Solution Approach 2:
The patent changes the chemical state of the first resist pattern by irradiating it with extreme ultraviolet light or electron beams, transforming it from a soluble state to an insoluble state in alkaline developers. This parameter change allows the first pattern to serve as a permanent mask, eliminating the need for subsequent removal steps and improving overall process efficiency.
2Manufacturing precision
If post-exposure bake and development steps are added, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent removes the post-exposure bake and development steps from the conventional double patterning process. By using irradiation with extreme ultraviolet light or electron beams to directly render the first resist pattern insoluble, these intermediate steps become unnecessary, simplifying the overall process while maintaining or improving overlay accuracy.
Solution Approach 2:
The patent replaces the thermal and chemical processing steps (post-exposure bake and development) with a radiation-based approach. By using extreme ultraviolet light or electron beams to directly modify the resist properties, the process eliminates the need for thermal treatment and chemical development, thereby reducing process complexity.
3Strength
If first resist pattern is made insoluble by irradiation, then etch resistance is improved, but manufacturing precision may deteriorate due to potential pattern deformation
Solution Approach 1:
The patent carefully controls the irradiation parameters (extreme ultraviolet light or electron beams) to achieve the desired degree of insolubility in the first resist pattern without causing excessive crosslinking or deformation. By optimizing the irradiation dose and conditions, the resist achieves sufficient etch resistance while maintaining pattern fidelity and formation 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
This approach enables a single dry etching process, improves overlay accuracy, and reduces the complexity of the patterning process, effectively addressing the limitations of existing double patterning techniques by enhancing etch resistance and pattern formation precision.
Implementation Method 1
a first positive resist composition with naphthol-based polymers that are crosslinked using high-energy radiation of up to 200 nm wavelength
Data Source
AI summary
A pattern is formed by applying a first positive resist composition onto a substrate, heat treatment, exposure, heat treatment and development to form a first resist pattern, the first positive resist composition comprising a polymer having copolymerized recurring units having naphthol and recurring units with an alkaline solubility that increases under the action of acid; causing the first resist coating to crosslink and cure by irradiation of high-energy radiation of sub-200 nm wavelength; further applying a second positive resist composition onto the substrate, heat treatment, exposure, heat treatment and development to form a second resist pattern. The double patterning process reduces the pitch between patterns to one half.