Transient events in thin films and interfaces have been studied using the technique of time resolved pump-probe nanosecond Brewster angle microscopy. For p-polarized light there is a minimum reflectivity at the Brewster angle. When the interface is viewed with light that is both incident and reflected at the Brewster angle the resulting image is dark. Subsequent small changes is refractive index will then cause an increase in the reflectivity in affected regions providing high contrast images of an altered interface with a dark background level. This is the basis of Brewster angle microscopy. In the present work two synchronized nanosecond pulsed lasers were used in the pump-probe configuration in order to induce changes at an air-liquid interface and to monitor the resulting morphology changes over a range of time delays from nanosecond to milliseconds after laser-excitation. This method can be used to observe morphological changes in phase altering thin-films and molecular monolayers. Further it can be used to obtain information about transient photochemistry even in optically thin materials and nano-films. In the current work the method is used to monitor laser induced processes in phase separating binary liquid mixtures as well as in monolayers of photo-responsive amphiphilic molecules derived from spiropyran on water. The two systems are quite different but provide valuable comparisons.
Line width roughness (LWR) reduction is a critical issue for low k1 ArF immersion lithography. Various approaches such as materials, exposure technology and the track process have been performed for LWR reduction during lithography process. It was reported that the post-development bake process had good performance for LWR reduction (1) . However, the post-development bake process induced large CD change owing to the degradation of large isolated resist pattern (2) . Therefore post-development process with small iso-dense bias is required in low k1 ArF immersion lithography. The resist smoothing process is one of the candidates for LWR reduction with small iso-dense bias. This method whereby the resist pattern surface is partially melted in organic-solvent atmosphere was shown to have a significant LWR reduction effect on resist patterns (3) . This paper reports on the application of the resist smoothing process to the ArF immersion resist pattern after development. It was found that the resist smoothing process was effective to reduce LWR for ArF immersion resist. As a result of LWR trace from after development to after the hard mask etching process, the effect of LWR reduction with the resist smoothing process continued after the hard mask etching process. Furthermore CD change of large isolated patterns with the smoothing process was smaller than in the case of postdevelopment bake process. We confirmed that the resist smoothing process is an effective method for decreasing LWR in ArF immersion lithography.
The lithography process on topographic substrate is one of the most critical issues for device manufacturing. Topographic substrate-induced focus variation occurs between top position and bottom position in a layer. That is, common depth of focus is reduced. This focus variation is sure to ruin the focus budget in low k1 lithography. From the focus budget of CMOS device (1) , substrate topography is required to be less than 30nm for hp 45-nm generation devices and less than 15nm for hp 32-nm generation devices. In this paper, the authors evaluate a novel concept for hp45-nm generation dual damascene layer for global surface planarization. The novel concept is thin planarization layer with bottom anti-reflecting (BAR) function. This planarization layer with optical performance is materialized by UV crosslink materials and process. This concept is expected to lead to a simpler planarization process. Thin planarization layer with BAR function clear BARC layer and simplifies the etching process. Our study showed that the planarization performance of UV crosslink layer with 100nm thickness was 20nm thickness bias between the field area and dense via hole area. This thickness bias achieved the requirement of hp 45nm generation. Furthermore, fine resist pattern was resolved on the planarization layer by the optimization of acid components and additive.
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