Commissariat a L'energie Atomique Et Aux Energies Alternatives

Other

Aselta Nanographics

Serdar Manakli

Luc Martin

Thomas Quaglio

Clyde Browning

Matthieu Millequant

A method for transferring a fractured pattern decomposed into elementary shapes, onto a substrate by direct writing by a particle or photon beam, comprises a step of identifying at least one elementary shape of the fractured pattern, called removable elementary shape, whose removal induces modifications of the transferred pattern within a preset tolerance envelope; a step of removing the removable shape or shapes from the fractured pattern to obtain a modified fractured pattern; and an exposure step, comprising exposing the substrate to a plurality of shots of a shaped particle or photon beam, each shot corresponding to an elementary shape of the modified fractured pattern. A computer program product for carrying out such a method is provided.

Method of reducing shot count in direct writing by a particle or photon beam

A computer implemented method of fracturing free form target design into elementary shots for defined roughness of the contour comprises determining a first set of shots which pave the target design and determining a second set of shots to fill the gaps. The dose levels of overlapping shots in the first or second sets of shots are determined so the compounded dose is adequate to the resist threshold, considering the proximity effect of the actual imprint of shots on the insulated target. A dose geometry modulation is applied and rounded shot prints are produced by shots not circular that may overlap. The degree of overlap is determined as a function of desired optimization of fit criteria between a printed contour and the contour of the desired pattern. Placements and dimensions of the shots are determined by a plurality of fit criteria between printed contour and contour of the desired pattern.

Free form fracturing method for electronic or optical lithography using resist threshold control

A method of electron-beam lithography by direct writing solves the reliability of design of etched components through rounding of the corners of contiguous patterns, notably in patterns to be etched of critical dimension of the order of 35 nm. The method determines critical patterns, and correction patterns by subtracting patterns of corrections of dimensions and of locations as a function of rounding of external or internal corners to be corrected and etching of the corrected design. The corrections may be by a correction model taking account of the parameters of the critical patterns. A correction of the proximity effects specific to these methods is also performed, by resizing of edges of blocks to be etched in combination optimized by the energy latitude with a modulation of the radiated doses. A rescaling and negation functions and eRIF functions may be used to optimize the parameters and the realization of the extrusion.

Method of electron-beam lithography with correction of corner roundings

A lithography method for a pattern to be etched on a support, notably to a method using electron radiation with direct writing on the support. Hitherto, the methods for correcting the proximity effects for dense network geometries (line spacings of 10 to 30 nm) have been reflected in a significant increase in the radiated doses and therefore in the exposure time. According to the invention, the patterns to be etched are modified as a function of the energy latitude of the process, which allows a reduction of the radiated doses.

Lithography method with combined optimization of radiated energy and design geometry

A lithography method based on the projection of cells, notably direct-write electron-beam lithography. One of the main limitations of the methods of this type in the prior art is the writing time. To overcome this limitation, according to the method of the invention, the size of the cells is increased to the maximum aperture of the lithography device. Advantageously, this size increase is obtained by modifying the size of the apertures of the projection stencil level closest to the substrate to be etched. Advantageously, a strip is added to the outside of the block to be etched onto which is radiated a dose calculated to optimize the process energy latitude. Advantageously, this strip is spaced apart from the edge of the block to be etched. Advantageously, the projected cells are not adjoining.

Large-mesh cell-projection electron-beam lithography method

A method of electron-beam lithography is provided, notably for technologies of critical dimension of the order of 22 nm. In such methods applied notably to networks of lines, the methods of the prior art do not offer precise and efficient correction of the shortenings of line ends. The method provided solves this problem by carrying out the insertion of contrast intensification structures of types which are optimized for the structure of the lines to be corrected. The method allows the semi-automatic or automatic calculation of the dimensions and locations of said structures. Advantageously, these calculations may be modeled to produce a target design, derived from libraries of components. They may be supplemented with a joint optimization of the size of the etchings and of the radiated doses, as a function of the process energy latitude.

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Meyrie, France

Serdar Manakli