Block Copolymer Structure for Microfabrication Pattern Orientation
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Solution Overview
Problem
Existing block copolymers face challenges in forming perpendicularly oriented patterns suitable for microfabrication due to high surface free energy differences between blocks, leading to roughness issues after etching, particularly when the interaction parameter is high, causing difficulties in achieving smooth phase-separated structures.
Innovation Solution
A block copolymer comprising a first block without silicon atoms and a second block with silicon atoms, where the silicon-containing block is positioned between the first and another silicon-containing block, is developed. This structure is formed through specific addition polymerization steps to control the interface thickness and surface energy, enabling improved pattern orientation and reduced roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a block copolymer with high interaction parameter χ is used to reduce interface thickness, then roughness after etching is reduced, but the difference in surface free energy between blocks becomes large, making it difficult to form perpendicularly oriented patterns
Solution Approach 1:
The second block is segmented into two sub-blocks: a silicon-containing block (b21) and an organometallic atom-containing block (b22). This segmentation allows the silicon-containing block to provide sharp interfaces for low roughness, while the organometallic block moderates surface free energy differences to enable perpendicular orientation, thus resolving the contradiction between roughness reduction and pattern orientation.
2Manufacturing precision
If the interface thickness between blocks is reduced by increasing interaction parameter, then edge definition improves, but surface free energy difference increases, causing segregation at surface during heat annealing
Solution Approach 1:
Different portions of the second block are assigned different functions: the silicon-containing block (b21) provides sharp phase separation and low interface thickness for good edge definition, while the organometallic atom-containing block (b22) provides balanced surface free energy to prevent segregation during heat annealing. This local differentiation resolves the contradiction between interface sharpness and surface stability.
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
The proposed block copolymer structure allows for the formation of smooth, perpendicularly oriented patterns with reduced roughness after etching, enhancing the precision and quality of microfabrication processes.
Implementation Method 1
it is necessary to form a self-organized nano structure by a microphase separation only in specific regions
Implementation Method 2
a technology in which a fine pattern is formed using a phase-separated structure formed by self-assembly of a block copolymer
Implementation Method 3
specific addition polymerization steps to control the interface thickness and surface energy
Data Source
AI summary
A block copolymer including a first block consisting of a polymer having a repeating structure of a structural unit (u1) containing no silicon atom, and a second block consisting of a polymer having a repeating structure of a structural unit (u2) containing a silicon atom, the second block containing a block (b21) consisting of a polymer having a repeating structure represented by general formula (u2-1), and a block (b22) consisting of a polymer having a repeating structure of a structural unit (u22) containing a silicon atom, and the block (b22) is positioned between the first block and the block (b21) (wherein RP211 represents an alkyl group, a halogenated alkyl group, a hydrogen atom, or an organic group having a polar group; and RP212 represents an organic group having a polar group).