Block Copolymer Nanostructure Formation via Selective Solution Etching
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Solution Overview
Problem
Existing methods for producing substrates with nanostructures using block copolymer phase separation face challenges in precisely reflecting the nanophase-separated structure, particularly due to issues with pattern collapse during solution etching and the need for costly equipment in dry etching.
Innovation Solution
A method involving phase separation of a block copolymer on a substrate, followed by decomposition and selective removal using a developing solution with specific organic solvents having an SP value of 7.5 to 11.5 (cal/cm3)1/2 and low vapor pressure, or benzene derivatives, to achieve precise nanostructure formation without pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching is used for selective removal, then manufacturing precision is improved, but device complexity and cost increase due to reduced-pressure equipment requirements
Solution Approach 1:
The patent replaces the mechanical dry etching system (requiring vacuum equipment and reactive gas introduction systems) with a chemical solution etching system. The selective removal is achieved through chemical dissolution in aqueous solutions rather than mechanical sputtering, eliminating the need for complex vacuum equipment while maintaining nanopattern precision.
Solution Approach 2:
The patent changes the etching environment from gas phase (dry etching) to liquid phase (solution etching). By using aqueous solutions with specific pH values and compositions, the patent achieves selective removal of polymer phases without requiring reduced-pressure conditions, thus simplifying the equipment while preserving manufacturing precision.
2Device complexity
If aqueous solution is used for selective removal, then device complexity is reduced, but manufacturing precision deteriorates due to pattern collapse
Solution Approach 1:
The patent optimizes the aqueous solution parameters including pH value, ionic strength, and temperature to control the etching rate and surface tension. By carefully adjusting these parameters, the patent achieves selective removal without causing pattern collapse, thus maintaining manufacturing precision while using simple equipment.
Solution Approach 2:
The patent introduces surfactants or specific salts as intermediaries in the aqueous solution to modify surface tension and prevent pattern collapse during etching. These additives act as mediators that allow the aqueous solution to selectively remove polymer phases without causing the structural instability that leads to pattern collapse.
3Productivity
If aqueous solution is used for selective removal, then productivity is improved through continuous processing, but manufacturing precision deteriorates due to pattern collapse
Solution Approach 1:
The patent optimizes aqueous solution parameters (pH, temperature, composition) to enable continuous processing while maintaining nanopattern integrity. The controlled chemical environment allows for extended processing times needed in continuous manufacturing without causing pattern collapse, thus improving productivity while preserving precision.
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 allows for the precise reflection of nanophase-separated structures on substrates, enabling the formation of nanostructures with desired shapes and sizes while avoiding pattern collapse and reducing the need for costly equipment.
Implementation Method 1
a phase separation step of forming, on a substrate, a layer containing a block copolymer having a plurality of blocks bonded together, and subsequently heating the layer to cause phase separation of the layer
Implementation Method 2
a selective removal step of immersing the layer in a developing solution and selectively removing a phase containing the block(s) decomposed in the decomposition step
Data Source
AI summary
A method for producing a substrate having a surface nanostructure, including a forming, on a substrate, a layer containing a block copolymer having a plurality of blocks bonded together, and subsequently heating this layer to cause phase separation of the layer; a decomposing at least a portion of the phase including at least one block of the plurality of blocks that constitute the block copolymer of this layer; and immersing the layer in a developing solution and selectively removing the phase containing the decomposed block(s), the developing solution containing, as the main component, an organic solvent having an SP value of 7.5 to 11.5 (cal/cm3)1/2 and a vapor pressure at 25° C. that is less than 2.1 kPa, or benzene which may be substituted with an alkyl group, an alkoxy group or a halogen atom.