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In advanced lithography, controlling the overlay budget is one of the most critical requirements. For device nodes at 10nm and below, there are many process-based sources of surface displacement that contribute to the lithography overlay budget that are independent of the lithography process, i.e. etch, anneal, CMP, etc. By developing an understanding of how process-induced surface displacement impacts overlay, displacement information can be fed-forward to the lithography tool for overlay correction during the lithography process. This paper describes the use of displacement measurement technology, the Coherent Gradient Sensing (CGS) interferometer, to characterize the effects of process-induced overlay error on the overlay budget through several processes in a typical semiconductor process flow. The CGS technique facilitates the generation of high-density displacement maps (>3 million points on 300mm wafer) such that the stresses induced die-by-die and process-by-process can be tracked in detail. Case studies are presented that summarize the use of the CGS data to reveal correlations between displacement variation and overlay variation, and demonstrate how feed forward can be applied for controlling overlay error.

This paper presents a novel systematic methodology to identify yield limiting killer defects by using KLA-Tencor's wafer inspection tools, Klarity Bitmap software and VIVA (Virtual Inspector Virtual Analyzer). This methodology covers two approaches: optimize inspection recipe through short-loop wafers from ADI (After-Develop Inspection) to AEI (After-Etch Inspection); re-optimize inspection recipe by using bitmap failures from Klarity Bitmap as hot spots to VIVA. The results of this study demonstrated that the chipmakers can potentially shorten the learning cycle for identifying killer defects by using this method.

Ozone is a strong oxidant that can selectively oxidize the color generating chromophoric parts of the organic compounds in waste waters. In this paper, the removal of color from waste waters produced in municipality, livestock farm, dye and pigment industries are investigated by mechanical diffuser (MD), dissolved ozone floatation (DOF), pressurized ozone oxidation (PO2) and combination of DOF-P02 processes. It is found that decolorization depends on the ozone dosage applied and the apparent concentration of the color imparting compounds in wastewaters. Result shows that 90% color removal efficiency from pigment wastewater is achieved using ozone dose of 108 mg/lscr, 210 mg/lscr and 60 mg/lscr by PO2, mechanical diffuser and combined DOF-PO2 system respectively. Moreover, 10 mg/lscr ozone can reduce the color of municipal waste water from 32 CU to 3 CU using DOF process alone. The order of efficiency among the applied ozonation techniques is found to be DOF-PO2 > PO2> DOF > MD. The more effective DOF-PO2 system is applied in removing color from dye, pigment and high suspended solid containing livestock wastewater and more than 90% color with suspended solids are removed in each case. Thus, ozonation, more particularly DOF-PO2 system is an efficient technology in removing color from various wastewaters.

Effluent of wastewater treatment plant is to be disinfected to protect drinking water sources. DOF(dissolved ozone flotation) was developed to meet this purpose. A DOF is strengthened system with ozone to a DAF(dissolved air flotation) system. A DAF system has good floating power by numerous micro-bubbles, and ozone has strong oxidation capability. And DOF system has good floating power and strong oxidation capability simultaneously. When DOF was applied to secondary wastewater effluent, color of 11CU in raw water that was secondary effluent was reduced to 1CU by the DOF system. Removal rate of other water quality parameters treated by DOF were also higher than that by DAF, which were proved the strength of oxidation capability of ozone. When ozone concentration of 6.1 mg/l were applied in DOF system, general aerobic bacteria were reduced to 5 CFU/ml from TNTC (too many numbers to count). With the same ozone concentration, total coliform were not detected at all. These figures are under the numbers of drinking water regulation. These microbes were the target major parameters of a DOF. It was proved that a DOF was very effective in disinfection of wastewater treatment plant effluent as well as in removal of color, turbidity, and T-P.

Compressing code is known to be one of the most effective methods of reducing the energy consumed in the interface between memory and processor. In this paper, we address the problem, which has not been tackled in the previous code compression techniques, of determining binary code of the instructions to be compressed. Our observation is that a careful assignment of binary code to the instructions to be compressed can lead to a considerable amount of power saving since the switching activity in instruction accesses varies significantly depending on the ways of assigning binary code to the instructions. To achieve the power saving, we analyze the problem and transform it into a graph optimization problem and solve it effectively by inventing an incremental node covering technique. From experiments using a set of benchmark programs, it is shown that the approach is quite effective, producing code with 17.3%-27.1% less power consumption in instruction accesses over a greedy (Gray-code based) low-power binary code assignment