Nano impression lithographic process which involves the use of a die having a region able to generate heat

#This is a National Stage entry of International Application PCT/IB2004/002120, with an international filing date of Jun. 22, 2004, which was published WO2004/114017, and the complete disclosure of which is incorporated into this application by reference.

#The present invention relates to a lithographic process for the production of structures for use in micro-devices and nano-devices, in particular in the fields of micro-electronics, nano-electronics, micro-fluidics, optics, opto-electronics, magnetic memories, micro-mechanics, nano-mechanics and sensors.

#One of the reasons for the rapid and continuous progress which has been possible in the field of micro-electronics during the last three decades is the reduction in the dimensions of devices and their massive integration into single chips. This reduction in scale of the dimension of devices seems also to be influencing other fields such as optics, mechanics and memorisation of data with the same degree of intensity and has given rise to new fields of technology such as micro-fluidics, micro-mechanics and nano-mechanics.

#Further advantages and characteristics of the present invention will be evident from the following detailed description, provided purely by way of non-limitative example with reference to the attached drawings, in which:

#FIGS. 1A to 1D schematically represent successive phases of a first embodiment of the process of the invention;

#FIGS. 2A to 2D schematically represent successive phases of a second embodiment of the process of the invention;

#A nano-impression lithographic process to form a pattern in relief on a mass of polymeric material 10 having any desired three dimensional form (FIG. 1A) to prepare a die 12 having a surface region 14 facing towards the body of polymeric material 10 and which reproduces in negative the pattern in relief to be impressed into the material 10.

#The body of the die 12 is of an electrically conductive material 16 preferably having a resistivity of less than 1 Ω*m and more preferably less than 0.0001 Ω*m. For example it can be a semi-conductor, preferably Si or SiC, or a metal, preferably chosen from the group consisting of Ti, Ni, Cr, Cu, Ag, Au, W, Ir, Ta, Pd, Mo, V and their alloys.

#The polymeric material 10 can be of thermoplastic type and is for example chosen from the group consisting of polycarbonates, polymethylmethacrylates, polyethyl methacrylates, polyethylene terephthalates, polyolefins and their mixtures. The mass of polymeric material 10 is then (FIG. 1B) brought into contact with and pressed against the die 12. The contact under pressure can be obtained in a conventional manner by mechanical action, or by electrostatic, magnetic or electro-magnetic force and/or with acoustic shock waves. Contemporaneously with the contact phase an electric current 16 is caused to pass (FIG. 1C) through the body of the die 12 where, by the Joule effect, it thus generates heat which is transmitted by conduction to the surface region 14. The passage of the current 18 may for example be caused by the application of a potential difference or exposure to a variable electro-magnetic or magnetic field. Preferably, the direction of the main flow of electric current 18 is perpendicular to the direction 19 of movement of the mass of polymeric material 10 with respect to the die 12.