Bifunctional Brush Layer for Directed Self-Assembly Lithography
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Solution Overview
Problem
Current methods for forming chemical guide patterns for directed self-assembly lithography in integrated circuit fabrication are complex and costly, making them impractical for large-scale manufacturing, limiting the ability to extend optical lithography beyond its pitch and resolution limits.
Innovation Solution
A bifunctional brush layer of polymeric material is formed over a semiconductor substrate, comprising a neutral and a pinning polymeric block portion, where one portion is selectively removed to create a chemical guide pattern, allowing a block copolymer layer to be phase-separated and registered to the guide pattern, thereby simplifying the process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical lithography is used for patterning, then manufacturing process is simple, but pitch and resolution are limited to about 80 nm
Solution Approach 1:
The patterning process is segmented into multiple steps: first forming a guide pattern using conventional lithography, then using directed self-assembly to form the final nanopattern. This segmentation allows each step to be optimized independently, achieving high resolution without requiring the entire process to be complex.
Solution Approach 2:
A guide pattern is formed in advance using conventional lithography before the final nanopattern is created. This preliminary action provides a template that directs the subsequent self-assembly process, enabling high-resolution patterning while keeping the initial lithography step simple.
2Manufacturing precision
If double or multi-patterning processes are used to achieve smaller pitch, then resolution is improved, but manufacturing cost and process complexity increase significantly
Solution Approach 1:
The block copolymer system performs self-assembly to form the final nanopattern without requiring complex external patterning steps. The materials automatically organize themselves into the desired pattern based on the guide pattern, eliminating the need for multiple lithography exposures and reducing process complexity.
Solution Approach 2:
The block copolymers undergo phase separation to form distinct A and B polymer regions with different affinities for the guide pattern. This phase transition enables spontaneous pattern formation at the nanoscale, achieving high resolution without additional lithography steps.
3Manufacturing precision
If current processes for forming chemical guide patterns are used, then directed self-assembly can be achieved, but the processes are complicated and costly
Solution Approach 1:
The guide pattern formation process is merged with the subsequent directed self-assembly steps into a unified workflow. The guide pattern is designed to work seamlessly with the block copolymer self-assembly, eliminating the need for separate, complex processing steps and reducing overall manufacturing complexity.
Solution Approach 2:
The guide pattern acts as an intermediary structure that translates conventional lithography patterns into directed self-assembly templates. This intermediary enables the transition from micrometer-scale lithography to nanometer-scale patterning without requiring direct nanolithography equipment.
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 the formation of nanopatterns with improved resolution beyond conventional optical lithography, facilitating cost-effective and scalable manufacturing of integrated circuits by using a single layer of polymeric material to create a bifunctional brush layer for chemical guide patterns.
Implementation Method 1
by annealing the DSA polymers, the A polymer chains and the B polymer chains undergo phase separation to form an A polymer region and a B polymer region that are registered to the underlying guide pattern
Implementation Method 2
Directed self-assembly (DSA), a technique which aligns self-assembling polymeric materials on a lithographically defined guide pattern
Data Source
AI summary
Methods for creating chemical guide patterns by DSA lithography for fabricating an integrated circuit are provided. In one example, an integrated circuit includes forming a bifunctional brush layer of a polymeric material overlying an anti-reflective coating on a semiconductor substrate. The polymeric material has a neutral polymeric block portion and a pinning polymeric block portion that are coupled together. The bifunctional brush layer includes a neutral layer that is formed of the neutral polymeric block portion and a pinning layer that is formed of the pinning polymeric block portion. A portion of the neutral layer or the pinning layer is selectively removed to define a chemical guide pattern. A block copolymer layer is deposited overlying the chemical guide pattern. The block copolymer layer is phase separated to define a nanopattern that is registered to the chemical guide pattern.