Double Patterning Resist Process for Sub-32nm Lithography
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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-32nm node resolutions.
Innovation Solution
A pattern forming process involving a first and second positive resist composition, where the first resist pattern is crosslinked and cured using high-energy radiation, allowing for a single dry etching step and improved overlay accuracy by forming a second resist pattern in the spaces of the first, thereby reducing pitch between patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If double dry etching is used to form patterns in double patterning process, then pattern formation is achieved, but throughput is reduced and process complexity increases
Solution Approach 1:
The patent extracts and removes one of the two dry etching steps from the conventional double patterning process. By using a negative tone resist for the first exposure that retains its pattern structure, the process eliminates the need for the first dry etching step, thereby improving throughput while maintaining pattern formation capability through the second exposure and development step
Solution Approach 2:
The patent applies preliminary action by performing the first exposure with negative tone resist that preserves the pattern structure without requiring subsequent etching. This preliminary pattern formation serves as a mask for the second exposure, allowing the second pattern to be formed directly through photoresist modification rather than requiring etching to transfer the first pattern
2Manufacturing precision
If double dry etching is used to form patterns, then pattern formation is achieved, but process complexity and misregistration risk increase
Solution Approach 1:
The patent removes one dry etching step from the process flow, directly reducing process complexity. The extracted etching step is replaced by a simplified two-step exposure process using negative tone resist that maintains pattern structure, thereby reducing both process steps and associated misregistration risks
Solution Approach 2:
The negative tone resist serves multiple functions: it forms the first pattern structure, acts as a mask for the second exposure, and eliminates the need for dry etching. This multi-functionality reduces process complexity by consolidating multiple steps into a single resist-based approach
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 process enhances throughput by eliminating the need for double dry etchings and improves overlay accuracy, enabling the formation of half-pitch fine-feature-size patterns with reduced misregistration, thus facilitating the production of sub-32nm node devices.
Implementation Method 1
irradiation of ultra-short wavelength radiation or electron beam (EB)
Implementation Method 2
irradiation of ultra-short wavelength radiation or electron beam (EB)
Implementation Method 3
irradiation of ultra-short wavelength radiation... for thereby reducing the distance between the patterns
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; causing the first resist pattern to crosslink and cure by irradiation of high-energy radiation of up to 180 nm wavelength or EB; 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.