Graphoepitaxy DSA Confinement Wells for Integrated Circuit Patterning
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Solution Overview
Problem
Current methods for fabricating integrated circuits using graphoepitaxy directed self-assembly are complex and costly due to the need for multiple photomasks, exposures, and lithography steps, limiting the scalability and efficiency of the process.
Innovation Solution
The method involves forming graphoepitaxy DSA directing confinement wells using the sidewall of an etch layer over a semiconductor substrate, filling them with block copolymers, and phase separating them to create an etch mask with a nanopattern, which reduces the reliance on photomasks and simplifies the lithographical process by utilizing existing topography or etched features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical lithography with multiple photomasks and exposures is used to achieve smaller pitch, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The block copolymer system performs self-assembly to automatically form the desired nanopattern without requiring external guidance or control during the self-assembly process. The BCP spontaneously separates into A and B domains, eliminating the need for complex photomask patterns and multiple lithography exposures to define the pattern geometry.
Solution Approach 2:
A lithographically defined guide pattern is formed beforehand on the substrate to pre-establish the spatial framework and chemical/topographical cues that will direct the subsequent self-assembly of block copolymers. This preliminary guide pattern enables the BCP to self-organize into the desired configuration without requiring complex real-time control during patterning.
2Manufacturing precision
If directed self-assembly with lithographically defined guide patterns is used, then pitch resolution is improved beyond optical limits, but process complexity increases due to additional layers and steps
Solution Approach 1:
The patent extracts and removes the etchable A polymer domains from the block copolymer structure, leaving behind only the etch-resistant B polymer domains as the final pattern. This selective removal simplifies the process by eliminating the need to preserve or process the A domains, reducing the number of subsequent manufacturing steps.
Solution Approach 2:
The patent changes the chemical composition and etchability parameters of the block copolymer components, making one block etchable and the other etch-resistant. This parameter differentiation allows for selective removal of one phase while preserving the other, simplifying the patterning process compared to approaches where both phases require separate handling.
3Ease of manufacture
If block copolymers are used for self-assembly, then patterning cost is reduced by eliminating photomasks, but manufacturing complexity increases due to phase separation control requirements
Solution Approach 1:
The patent applies different local qualities to different regions of the block copolymer system: the guide pattern regions provide chemical and topographical cues that direct self-assembly, while the bulk BCP provides the phase separation mechanism. The lithographically defined guide pattern creates local variations in surface energy and topology that guide the BCP domains to specific locations without requiring complex global control mechanisms.
Solution Approach 2:
The patent replaces complex mechanical or optical control systems (multiple photomasks, alignments, and exposures) with a self-organizing chemical system. The block copolymer phase separation is driven by thermodynamic forces and molecular interactions rather than external mechanical manipulation, simplifying the overall manufacturing system.
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 decreases the complexity and cost of patterning by eliminating or minimizing the need for additional photomasks and lithography steps, enabling more efficient and scalable fabrication of integrated circuits.
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
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 fabricating integrated circuits are provided. In one example, a method for fabricating an integrated circuit includes forming a graphoepitaxy DSA directing confinement well using a sidewall of an etch layer that overlies a semiconductor substrate. The graphoepitaxy DSA directing confinement well is filled with a block copolymer. The block copolymer is phase separated into an etchable phase and an etch resistant phase. The etchable phase is etched while leaving the etch resistant phase substantially in place to define an etch mask with a nanopattern. The nanopattern is transferred to the etch layer.