Commissariat a L'energie Atomique Et Aux Energies Alternatives

Etienne Rognin

Stefan Landis

Vincent Reboud

A method for determining at least one reflow parameter for obtaining a structure approximating a sought structure by reflowing an initial structure different to the sought structure, the initial structure including at least one pattern formed in a thermo-deformable layer arranged on a substrate. The thermo-deformable layer forms a residual layer surrounding each pattern and from which each pattern extends such that each pattern has an interface only with the surrounding medium. The method includes: predicting progression over time of geometry of the initial structure subject to reflow, to obtain a plurality of predicted structures each associated with reflow parameters including at least a reflow time and a reflow temperature; computing correlation values of the geometry of each predicted structure with respect to the sought structure; identifying reflow parameters for obtaining the predicted structure offering a highest correlation value.

Method for obtaining at least one structure approximating a sought structure by reflow

A method is provided for determining the viscosity of thin films which exhibit a viscous behavior at a measurement temperature, notably for polymer resins above their glass transition temperature. A thin layer of material is formed on a substrate, a known geometrical pattern is impressed in the thin layer by molding or etching, the thin layer being in the solid state at the end of the impression step. The initial topography of the impressed pattern is measured over the entire length of the pattern along a determined direction, the film is baked at the measurement temperature Tm for a determined creep time t, and the resulting topography of the crept pattern is measured. Mathematical processing of the topography measurements is carried out in order to deduce a value of viscosity at the measurement temperature therefrom. The impressed pattern at the start is aperiodic.

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Le Havre, France

Etienne Rognin