Making Gradient Patterns by Electron‐Beam Chemical Lithography with Monomolecular Resists

Maskless Ultraviolet Projection Lithography with a Biorepelling Monomolecular Resist

“…30 Significantly, the extent of the exchange reaction can be precisely controlled by the irradiation dose, which allows us to vary the content of the substituent, resulting in complex chemical patterns. 8,35 Among different types of SAMs, OEG-substituted ones are of special interest because of their protein-repelling properties. This is of particular importance for protein or single-stranded DNA arrays where, usually, predefined sensing spots are embedded into the OEG matrix, which prevents the nonspecific adsorption of biomolecules.…”

“…In the case of chemical lithography, a chemical pattern can be fabricated after the exchange reaction with a suitable SAM-forming substituent . Significantly, the extent of the exchange reaction can be precisely controlled by the irradiation dose, which allows us to vary the content of the substituent, resulting in complex chemical patterns. , …”

“…Self-assembled monolayers (SAMs), which are densely packed films of rod-like molecules chemically attached to a suitable substrate, are versatile and frequently used as resist or template materials for lithography. The experimental approaches include both SAM-specific methods such as microcontact printing and dip-pen nanolithography as well as standard lithographic tools like electron beam and photolithography (predominately, with ultraviolet light). − The latter techniques have certain advantages since they can rely on quite established fabrication setups and allow both parallel and sequential patterning. A parallel patterning is usually performed in the proximity printing geometry, using a stencil mask. , In contrast, sequential patterning is conducted with a focused beam, as this, e.g., occurs in a secondary electron or transmission electron microscope (SEM and TEM, respectively) equipped with a proper lithographic control unit. ,,, This patterning mode is of course slower than the parallel writing but offers distinctly higher lateral resolution (defined, in the given case, by the diameter of the primary beam) and full flexibility in terms of the pattern shape.…”

Modification of Nitrile-Terminated Biphenylthiol Self-Assembled Monolayers by Electron Irradiation and Related Applications

“…The related applications range from chemical sensors over nanofabrication and molecular electronics to biological and medical issues. 1,3 Some of these applications do not only rely upon the specific design of the SAM-building monomers but on modification of SAMs by ionizing radiations such as electrons, 5,6 X-rays, 7,8 or deep/extreme UV light, 9,10 with the primary role of electrons in the underlying processes. 11,12 Significantly, the character of the modification depends on the identity of the SAM constituents, above all on the molecular chain.…”

“…Self-assembled monolayers (SAMs) represent a useful tool to prepare well-defined and chemically uniform surfaces and interfaces. − In addition, due to a broad variety of SAM-building monomers, they enable tuning the surfaces properties with regard to chemical reactivity, wettability, or biocompatibility. The related applications range from chemical sensors over nanofabrication and molecular electronics to biological and medical issues. , Some of these applications do not only rely upon the specific design of the SAM-building monomers but on modification of SAMs by ionizing radiations such as electrons, , X-rays, , or deep/extreme UV light, , with the primary role of electrons in the underlying processes. , Significantly, the character of the modification depends on the identity of the SAM constituents, above all on the molecular chain. , In particular, monolayers comprising aliphatic moieties are predominately degenerated under electron irradiation . Therefore, aliphatic SAMs are generally considered as a positive resist in electron beam lithography, although it was reported that, under the circumstances, they can also act as a negative resist .…”