Study on radiation transfer, which is the key process in the energy balance system, is required to interpret remote sensing
data and support application. In the radiation transfer process, atmospheric transmittance is the most important physical
parameter in study of remote sensing, especially in the quantitative remote sensing. The paper mainly studies on
atmospheric transmittance based on MODIS and FY. In the paper, it calculates gaseous absorption of seven gases
including water vapor, carbon dioxide, ozone, nitrous oxide, carbon monoxide, methane, and oxygen (H2O, CO2, O3,
N2O, CO, CH4 and O2) by MODTRAN. Then it makes convolution transforms, fit and regress the polynomials to obtain
the corresponding coefficients of each polynomial and different relative spectral response. At last, it calculates
atmospheric transmittance by the fitted polynomials compared with the results of MODTRAN to validate. Based on the
study, it lays a foundation for studying and application on Daily BRDF/Albedo Algorithm for FY-3 next.
Critical dimension (CD) is one the most critical variable in the lithography process with the most direct impact
on the device speed and performance of integrated circuit. The development rate can have an impact on the CD
uniformity from wafer-to-wafer and within-wafer. Conventional approaches to controlling this process include
monitoring the end-point of the develop process and adjusting the development time or concentration from
wafer-to-wafer or run-to-run. This paper presents an innovative approach to control the development rate in
real-time by monitoring the photoresist thickness. Our approach uses an array of spectrometers positioned
above a programmable bakeplate to monitor the resist thickness. The develop process and post-development
bake process is integrated into one equipment. The resist thickness can be extracted from the spectrometers
data using standard optimization algorithms. With these in-situ measurements, the temperature profile of the
bakeplate is controlled in real-time by manipulating the heater power distribution using a control algorithm. We
have experimentally obtained a repeatable improvement in controlling the end-point of the develop process from
wafer-to-wafer and within wafer.
An in-situ method to control the steady-state wafer temperature uniformity during thermal processing in microlithography is presented. Based on first principle thermal modeling of the thermal system, the temperature of the wafer can be estimated and controlled in real-time by monitoring the bake-plate temperature profile. This is useful as production wafers usually do not have temperature sensors embedded on it, these bake-plates are usually calibrated based on test wafers with embedded sensors. However as processes are subjected to process drifts, disturbances and wafer warpages, real-time correction of the bake-plate temperatures to achieve uniform wafer temperature at steady-state is not possible in current baking systems. Any correction is done based on run-to-run control techniques which depends on the sampling frequency of the wafers. Our approach is real-time and can correct for any variations in the desired steady-state wafer temperature. Experimental results demonstrate the feasibility of the approach.
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