Method and apparatus for positioning a micro- or nano-object under visual observation

#This application is a National Stage of International patent application PCT/EP2017/056982, filed on Mar. 23, 2017, which claims priority to foreign French patent application No. FR 1653247, filed on Apr. 13, 2016, the disclosures of which are incorporated by reference in their entirety.

#The invention relates to the positioning of a micro- or nano-object above a planar support, performed under visual control. It relates to the field of nanotechnologies and applies, in particular, to local probe microscopy (and more particularly to electrochemical microscopy) and to nano-fabrication.

#A “micro-object” should be understood to be any object having at least one dimension less than or equal to 10 μm. A “nano-object” should be understood to be any object having at least one dimension less than or equal to 1 μm or even, according to a more restrictive definition, to 100 nm (in which case, between 100 nm and 1 μm, the object will be called “sub-micrometric”).

#Other features, details and advantages of the invention will emerge on reading the description given with reference to the attached drawings given by way of example, in which:

#FIG. 1 illustrates the principle of the BALM technique, based on the present invention;

#FIGS. 2A and 2B schematically illustrate the application of a method according to an embodiment of the invention to the positioning of a scanning microscopy local probe;

#The figures are not to scale. In particular, the thickness of some layers (and in particular the absorbent antireflection layer) is very greatly enlarged in the interests of clarity.

#Hereinbelow, a material will be considered absorbent to a wavelength λ when the imaginary part of its refractive index at this wavelength is greater than or equal to 0.0001, preferably to 0.001, even more preferably to 0.01. Otherwise, it will be considered transparent.

#FIG. 1 provides a review of the theory of absorbent antireflection layers, already explained in the abovementioned international application WO 2015/055809. It illustrates a parallel light beam FL (that can be likened locally to a planar wave) that is also monochromatic at a wavelength (in vacuum) λ, at normal incidence on a structure consisting of: a semi-infinite medium called incident medium MI, from which the light beam originates, which is transparent and characterized by a real refractive index n0; an absorbent layer CA of thickness e1, characterized by a complex refractive index N1=n1−jk1 (“j” being the imaginary unit); and a semi-infinite medium, called emergent or ambient medium MA, situated on the side of the layer opposite that from which the light originates, which is transparent and characterized by a real refractive index n3<n0. The incident medium can in particular be a substrate, for example of glass, on which the layer CA is deposited.