Asymmetric fluid-structure dynamics in nanoscale imprint lithography

In the imprinting process, it has been shown that defects due to particlecontamination can be removed by first using a sacrificial wafer to perform initialimprinting to remove the particles. Upon repeated imprinting, particles remain onthe sacrificial wafer. However, for the active stage test bed, there is no currentcapability to perform this imprinting. Thus, it is very difficult to obtain particlefreegap between the quartz and substrate.6.5.2 Signal ProcessingIn the process of collecting gap data, noise or distortion is introduced intothe reflectivity intensity data. Consider that the light received by the spectrometerconsists of three components as follows:where⎛ n ⎞ ⎛ n ⎞R⎜⎟ = I⎜⎟ ∗ S⎝ λ ⎠ ⎝ λ ⎠( λ) ∗ K( t)[6.1]⎛ n ⎞I⎜⎟ is the actual reflectance of the film under consideration. It is a⎝ λ ⎠function of the index of refraction n and wavelength λ. S ( λ)is a function, whichcharacterizes the wavelength dependence of the optical components of thesystem. K () t is a function that allows for time-dependent intensity variationssuch as changes in the illumination intensity of the light source (in this case thetungsten-halogen lamp), sample placement, angle of incidence, focus, etc.In the best-case scenario, S ( λ)and K () t do not contain periodic data.Typically, this can be assumed for S ( λ), since spectrometer manufacturersusually design these optical systems taking this into consideration. However, itwas observed that K () t does contain periodic information and generates a signal95