Patent ID: 7716026
Filing Date: 2010-05-11
Classification: B82Y,G03F

Abstract:
1. A non-destructive method for inverse-calculating a fiber probe aperture size and a prediction method of a fabrication profile of near field photolithography, comprising: a first step of building a theoretical model of near field photolithography, including a theoretical model of a point fabrication of near field photolithography and a theoretical model of a line fabrication of near field photolithography; a second step of setting an error between a simulation result of the theoretical model of the line fabrication of near field photolithography and an experimental result of a line lithography fabrication as an objective function; a third step of searching for a reasonable convergence criteria through Levenberg-Marquardt method and inverse-calculating a fiber probe aperture size that matches with the line lithography experiment and the theoretical model of the line fabrication of near field photolithography; a forth step of comparing a fabrication profile of the line lithography experiment and that of the simulation result of the inverse-calculated probe aperture size, so as to verify that the inverse-calculated fiber probe aperture size is reasonable; and a fifth step of predicting the fabrication profile of near field photolithography by combining with the parameter control of near field photolithography, by means of inverse-calculating the fiber probe aperture size; wherein the step of building the theoretical model of the line fabrication of near field photolithography comprises the following detailed steps (1)-(6): (1) a near-field optical power density of the fiber probe is analyzed by a radiation field theory, and a normalized near-field power density at a near-field observation point of the fiber probe is calculated as follows: wherein I (2) an exposure energy density distribution of the line lithography is analyzed by an exposure energy density integral formula, and the exposure energy density formula is shown as follows: wherein E (3) the interior of the photoresist is divided into limited nodes with coordinates of ((x,y),h) and a concentration change of a photoactive compound (PAC) at each internal limited node after the photoresist is exposed is calculated by combining with the exposure energy density integral formula; (4) the interior of the photoresist is divided into each node with coordinates of ((x wherein: I M t: an exposure time; (5) the interior of the photoresist is divided into each node with coordinates of ((x R R R M n: a selection factor; (6) M the step of setting an error between a simulation result of the theoretical model of the line fabrication of near field photolithography and an experimental result of a line lithography fabrication profile of the section for the line lithography in the numerical operation is obtained through the above derived theoretical model of the line fabrication of near field photolithography; (2) penalty function weights are set, φ (3) J, g, and H are respectively calculated; wherein J represents Jacobian Matrix, g and H contain the first and second derivatives, respectively, of the inverse barrier function with respect to the parameters and the calculation formulas thereof are shown as follows: (4) a parameter increment δ wherein: Λ represents the Marquardt parameter, the residual vector, r, is defined by: fabrication as an objective function comprises the following detailed steps (1)-(2): (1) a striograph of the line fabrication experiment of near field photolithography is appropriately gridded, so as to retrieve point data of the lithography fabrication profile; (2) an error between the simulation result of the theoretical model of the line fabrication of near field photolithography and the experimental result of the line lithography is set as an objective function, and the objective function formula is: wherein, H H m represents the number of points measured on a section of the line lithography, ψ(p) is called an inverse barrier function; the step of searching for a reasonable convergence criteria through Levenberg-Marquardt method and inverse-calculating a fiber probe aperture size that matches with the line lithography experiment and the theoretical model of the line fabrication of near field photolithography comprises the following detailed steps (1)-(8): (1) a set of initial unknown parameters p r is expressed in a matrix as follows: (5) a newly-estimated parameter value is obtained by p (6) the newly-obtained parameter is substituted into the theoretical model of the line fabrication of near field photolithography, to obtain a new point data H (7) a new objective function E* (8) if the convergence criteria {|δ in the step of building the theoretical model of near field photolithography, building the theoretical model of a point fabrication of near field photolithography comprises the following detailed steps (1)-(2): (1) the near-field optical power density of the fiber probe is analyzed by the radiation field theory, and the normalized near field power density at the observation point of the fiber probe is calculated as: wherein, I (2) the exposure energy density distribution of a point lithography fabrication is analyzed by the exposure energy density formula of a static fixed point, and when performing the point fabrication of near field photolithography, the energy density absorbed by the photoresist surface is: wherein E