Directed Self-Assembly Pattern Formation for Sub-90nm Lithography
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Solution Overview
Problem
Current pattern-forming methods for electronic devices, such as semiconductor and liquid crystal devices, face challenges in achieving finer patterns due to limitations in the miniaturization of structures, particularly in forming patterns with line widths smaller than 90 nm, and require improved methods for directed self-assembly to enhance microfabrication.
Innovation Solution
A pattern-forming method involving the formation of a silicon-containing film, a prepattern with a first polymer, an underlayer film with a second polymer having specific molecular structures, and a block copolymer for directed self-assembled film formation, followed by phase separation and etching to create a patterned substrate with improved orientationality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography methods are used for pattern formation, then current manufacturing capabilities are maintained, but further miniaturization of patterns below 90 nm line width cannot be achieved
Solution Approach 1:
The block copolymer system performs self-assembly to form ordered micellar structures with precise spacing and orientation without requiring external guidance. The polymer chains spontaneously organize into domains with characteristic dimensions determined by their molecular architecture, enabling sub-90nm pattern formation through intrinsic self-organization rather than external lithographic control
Solution Approach 2:
The patent controls the domain size and pattern dimensions by adjusting polymer composition ratios, molecular weights, and annealing temperature parameters. By varying the block copolymer composition (e.g., PS-PB-PS triblock ratios) and processing conditions (annealing temperature, solvent composition), the characteristic pattern dimensions can be tuned to achieve desired sub-90nm line widths
2Manufacturing precision
If directed self-assembly of block copolymers is used, then finer patterns can be formed, but control over phase separation orientation and uniformity becomes challenging
Solution Approach 1:
A prepattern layer is formed on the substrate before applying the block copolymer composition. This prepattern provides predetermined guidance structures (such as trenches or pillars) that direct the orientation and positioning of the subsequent block copolymer self-assembly, ensuring uniform domain alignment and preventing random orientation that would compromise pattern reliability
Solution Approach 2:
The patent introduces an intermediary layer or surface treatment between the substrate and block copolymer that mediates the interaction. This intermediary layer (such as a thin film of specific material or surface-modified prepattern) provides controlled adhesion and directional cues that guide the phase separation process, ensuring uniform orientation without requiring direct contact between the block copolymer and substrate
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 method enables the formation of substrates with superior phase separation structures, enhancing the orientationality and suitability for advanced lithography processes in microfabrication, particularly for semiconductor and liquid crystal devices requiring further miniaturization.
Implementation Method 1
Phase separation of the coating film is allowed to form a directed self-assembled film having phases
Data Source
AI summary
A pattern-forming method includes forming a prepattern and including a first polymer is formed on a silicon-containing film on a substrate. An underlayer film including a second polymer is formed in recessed portions of the prepattern. A composition for directed self-assembled film formation including a third polymer is applied on the underlayer film and the prepattern. The first polymer includes a first structural unit. The second polymer includes: a molecular chain including the first structural unit and a second structural unit that differs from the first structural unit; and an end structure that bonds to one end of the molecular chain and includes at least one selected from the group consisting of an amino group, a hydroxy group and a carboxy group. The third polymer is a block copolymer including a block of the first structural unit and a block of the second structural unit.