With decreasing of critical dimension (CD), the availability of depth of focus (DOF) goes down from technology node to technology node. Monitoring and controling of scanner focus on product wafers will be necessary. A technique entitled Iso-Dense Focus Monitor(IDFM) is developed to measure the focus errors of scanner systems. This IDFM method uses double side chrome mask and iso-dense binary overlay mark. The accuracy of this IDFM technique using binary mark may equal to the conventional PGFM method, and the IDFM technique only expose the wafer one time comparing with Z-SPIN which may expose two times. This method was simulated and also implemented on a litho tool of SMEE SSA600/10.
Based on the in-line metrology sampling and modeling, the Advanced Process Control (APC) system has been widely
used to control the combined effects of process errors. With the shrinking of overlay budgets, the automated optimized
overlay management system has already been necessary. To further improve the overlay performance of SMEE
SSA600/10A exposure system, the overlay manager system (OMS) is introduced. The Unilith software package
developed by SMEE included in the OMS is used for the decomposition and analysis of sampled data. Several kinds of
correction methods integrated in the OMS have been designed and have demonstrated effective results in automated
overlay control. To balance the overlay performance and the metrology time, the exponential weighting method for
sampling is also considered.
The structural, morphological and optical properties of zinc oxide (ZnO) thin films were investigated. The ZnO thin
films were deposited on glass substrate at room temperature (RT) through radio frequency magnetron sputtering in
different O<sub>2</sub> flux (fixed Ar flux). The structural properties and morphology were studied by X-ray diffraction and atomic
force microscopy, respectively. The highly crystallized ZnO thin films were obtained. It is found that all the films have
preferential orientation in c-axis direction and the crystallinity of the films is strongly affected by O<sub>2</sub> flux. The
crystallinity is improved greatly when the film is annealed in O<sub>2</sub> ambient. Atomic force microscopy results show that the
films are compact and smooth. Near band edge emission peak in photoluminescence spectrum for the typical sample
appears red-shift phenomena. All the films present a high transmittance of above 90% in the visible region.