Direct Self-Assembly DSA

On the other hand, annealing in THF-DPM (diphenylmethane) (1 1 v/v) mixed solvent causes a well-ordered array of dots occurring over large areas of the sample compared to the deposited film. Introducing a small amount of DPM solvent vapor can help us to avoid preferential wetting of the PTFEMA cylinders to the polymer-solvent vapor interface. This shows that the choice of solvent used for annealing allows for control of a self-assembled morphology. 

PS-fc-PMMA (diblock polystyrene polymethylmethacrylate) is one of title typical diblock polymers. Nanostructure fabrication of direct self-assembly 

Cross-finked PS PMMA degraded in exposed areas. 

Topton, V. Marriott, and G. Fuller, Solid State Technol, 30 (1987) 53. 

Moreau, Semiconductor Lithography Principles, Practices, and Materials, Plenum Press, New York (1988), p. 365. 

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Direct self-assembly (DSA) pays attention to pattern formation in materials smaller than 20 nm in size. DSA does not require special equipment for patterning, which is different from immersion lithography and nanoimprint. Pattern formation is performed by microphase separation in the DSA process. DSA patterning is quite different from conventional patterning. Diblock polymers composed of hydrophilic and hydrophobic polymer units are applied for DSA materials. Diblock polymers of the A-B type, where the A block is reciprocal to the B-block, accelerate to concentrate in the same block. A diblock polymer produces self-assembly and microphase separation by formation of a sphere, cylinder, and lamellar, which are controlled by product P of the % parameter (Flory interaction parameter) and degree of polymerization N siP = Z ab)- Classical structures of phases are shown in Figure 3.20. 

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