Patent ID: 6483597
Filing Date: 2002-11-19
Classification: B82Y,C23C,G21K

Abstract:
A method for the production of multi-layer systems with N layers having predetermined thickness, especially for the production of multi-layer systems for wavelength ranges in the extreme ultraviolet and soft X-ray wavelength range, in which N layers are deposited and if need be one or more layers are partially removed after deposition and in which at the same time as deposition and/or removal of layer, their reflectivity dependent on layer thickness is measured, with the following steps:calculation of a reflectivity-time curve of the multi-layer system to be produced considering the deposition rate and/or the removal rate, the layer materials, the predetermined layer thicknesses and the wavelength and angle of incidence of the beam used to measure the reflectivity; determination of points in time ti (i=1, 2, . . . , N), at which the deposition of the i-th layer is to be stopped; and if need be determination of points in time tiâ€² (i=1,2 . . . , N), at which the partial removal of the i-th layer is to be stopped, and at which the reflectivity at ti or tiâ€² is in the range of a turning point of the reflectivity-time curve; calculation of parameters ki (i=1,2, . . . , N) for deposition and if need be kiâ€² (i=1, 2, . . . , N) for partial removal, at which ki and kiâ€² are defined as ratios of intensity values at predetermined values of the reflectivity curve; deposition of the first layer with simultaneous reflectivity measurement; and calculation of the current parameter kc/i based on intensities of the reflectivity measurement; stopping of the deposition as soon as kc/i=ki; and if need be partial removal of the first layer with simultaneous reflectivity measurement and calculation of the current parameter Kcâ€²/i based on intensities of the reflectivity measurement; stopping of the partial removal as soon as kcâ€²i=kiâ€²; repetition of the previous steps for all subsequent layers up to and including layer N.