Block Copolymer Directed Self-Assembly for Sub-Resolution Patterning
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Solution Overview
Problem
Current methods for forming fine patterns in semiconductor devices face limitations due to image resolution constraints in photolithography, particularly in creating patterns with different shapes on a substrate using directed self-assembly of polymer molecules.
Innovation Solution
A method involving the formation of pillars and peripheral patterns on an underlying layer, followed by the deposition of a separation wall layer and a block copolymer layer, which undergoes annealing to create domains that are selectively removed to expose the underlying layer, allowing for the formation of nano-scale patterns through a series of etching and patterning steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If photolithography process is used to form patterns, then manufacturing process is simple and fast, but pattern size is limited by image resolution constraints
Solution Approach 1:
The patent introduces block copolymer molecules as an intermediary substance between the photolithography process and the final pattern formation. These molecules self-assemble into micelle structures with specific geometries (spheres, cylinders, lamellae) that define the final pattern shapes, enabling sub-resolution patterning beyond the optical system's diffraction limit
Solution Approach 2:
The patent changes the physical and chemical parameters of the patterning system by using block copolymers with different block ratios, molecular weights, and compositions. By adjusting these parameters, different micelle morphologies are obtained, enabling formation of patterns with different shapes and sizes that overcome the fixed resolution constraint of photolithography
2Manufacturing precision
If directed self-assembly of polymer molecules is used to form fine patterns, then pattern resolution is improved, but ability to form different pattern shapes simultaneously is limited
Solution Approach 1:
The patent applies local quality by creating different pattern regions with distinct characteristics on the same substrate. By controlling the block copolymer composition, molecular weight, and annealing conditions in different areas, various micelle morphologies (spherical, cylindrical, lamellar) are formed locally, enabling simultaneous creation of different pattern shapes across the wafer
Solution Approach 2:
The patent uses composite block copolymer materials consisting of different polymer blocks (e.g., polystyrene-block-poly(methyl methacrylate)) with specific properties. The combination of incompatible polymer blocks creates microphase-separated structures that self-assemble into different geometries, providing versatility in pattern shape formation while maintaining high resolution
3Manufacturing precision
If multiple patterning techniques are developed to overcome resolution limits, then pattern formation capability is improved, but process complexity increases
Solution Approach 1:
The patent employs self-service by utilizing the inherent self-assembling property of block copolymer molecules. The molecules automatically organize into ordered micelle structures through thermodynamic driving forces during annealing, eliminating the need for complex multiple patterning steps, alignment procedures, and repeated lithography cycles required by conventional approaches
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 creation of fine patterns with different shapes and sizes, overcoming the resolution limits of traditional photolithography and enhancing integration density in semiconductor devices.
Implementation Method 1
annealing the block copolymer layer to form first domains and a second domain surrounding the first domains from the block copolymer layer, the second domain isolating the first domains from each other
Implementation Method 2
forming a separation wall layer on the underlying layer to cover sidewalls of the pillars and sidewalls of the first peripheral patterns
Data Source
AI summary
A method of forming patterns includes forming pillars and first peripheral patterns on an underlying layer, forming a separation wall layer covering sidewalls of the pillars and the first peripheral patterns, forming blocking portions on the separation wall layer to fill first openings between the first peripheral patterns, forming a block copolymer layer filling gap regions between the pillars, annealing the block copolymer layer to form first domains and a second domain surrounding the first domains, removing the first domains and removing portions of the separation wall layer to form second openings, removing the second domain and the blocking portions, removing the pillars and the first peripheral patterns to form third openings and fourth openings, and patterning the underlying layer to form fifth openings that extend from the second and third openings and sixth openings that extend from the fourth openings.