Block Copolymer Directed Self-Assembly for Sub-22nm Semiconductor Patterning
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Solution Overview
Problem
Current lithography techniques face challenges in forming patterns with dimensions less than 22 nm, and existing double patterning methods are complex and costly, limiting the ability to achieve finer pitch patterns.
Innovation Solution
A method involving the use of block copolymers for directed self-assembly, where a polymer thin film is imprinted with a stamp to form patterns, allowing for the selective removal of domains to create finer pitch patterns without the need for exposure, using techniques like nano-imprinting and dry/wet etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography is used, then existing pattern formation methods are simple, but pattern dimensions cannot achieve less than 22 nm
Solution Approach 1:
The patent applies segmentation by dividing the pattern formation process into two distinct stages: first forming a mandrel pattern through lithography, then using that mandrel as a template for block copolymer self-assembly to create the final fine-pitch pattern. This segmentation allows each stage to operate at optimal resolution levels, achieving sub-22nm patterns without requiring the entire process to operate at that resolution.
Solution Approach 2:
The mandrel structure serves as an intermediary element between the lithography process and the final pattern. The lithographically defined mandrel pattern acts as a template that guides the self-assembly of block copolymers, mediating the transition from lithographic resolution to finer self-assembled features. This intermediary approach allows the system to overcome the resolution limit of conventional lithography.
2Manufacturing precision
If double patterning methods (LELE, LFLE, sidewall spacers) are used, then finer pitch patterns can be achieved, but process complexity and cost increase significantly
Solution Approach 1:
The patent employs self-service through directed self-assembly of block copolymers. The block copolymer system automatically organizes itself into ordered domains guided by the mandrel template, eliminating the need for additional lithography steps, alignment procedures, and complex process control that characterize conventional double patterning methods. The self-assembly process inherently provides the necessary precision without external intervention at each stage.
Solution Approach 2:
The patent utilizes parameter changes by controlling the self-assembly process through temperature, solvent conditions, and annealing parameters. By adjusting these physical and chemical parameters, the block copolymer system transitions from a disordered state to an ordered self-assembled structure, achieving fine pitch patterns through controlled phase separation rather than through multiple lithographic exposures.
3Manufacturing precision
If block copolymer self-assembly is used, then sub-lithographic features can be formed, but additional process steps (exposure, mask construction) are required
Solution Approach 1:
The patent applies preliminary action by pre-forming the mandrel pattern through conventional lithography before initiating block copolymer self-assembly. This preliminary lithographic step creates a template that directs subsequent self-assembly, allowing the system to achieve sub-lithographic features while using the simpler lithographic process for the initial pattern definition. The preliminary mandrel structure remains in place to guide the formation of finer features.
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
Enables the formation of finer pitch patterns with simpler processes, reducing complexity and cost compared to existing methods, while allowing for precise control over pattern formation and semiconductor device manufacturing.
Implementation Method 1
a block copolymer (BCP) or polymer compounds is deposited on a substrate through, generally, spin coating, and is 'directed' to form ordered structures through annealing
Implementation Method 2
blocks of such copolymer phases are separated into micro domains (also called 'domains'), during which nanoscale features are formed for different chemical combinations
Implementation Method 3
forming a first pattern through imprinting the polymer thin film with a stamp
Implementation Method 4
selectively removing a domain composed of a copolymer component to form a second pattern
Data Source
AI summary
A pattern formation method, mask pattern formation method and a method for manufacturing semiconductor devices are provided in this disclosure, which are directed to the field of semiconductor processes. The pattern formation method comprises: providing a substrate; forming a polymer thin film containing a block copolymer on the substrate; forming a first pattern through imprinting the polymer thin film with a stamp; forming domains composed of different copolymer components through directed self assembly of the copolymer in the first pattern; selectively removing the domains composed of copolymer components to form a second pattern. In the embodiments of the present invention, finer pitch patterns can be obtained through combining the imprinting and DSA process without exposure, which as compared to the prior art methods has the advantage of simplicity. Furthermore, stamps used in imprinting may have relative larger pitches, facilitating and simplifying the manufacture and alignment of the stamps.