Wafer design and characterization

Wafer Design and Characterization for Integrated-Circuit Processes... 

Fig. 11.8 Schematic of the automated primary high-throughput electrochemical workflow employed at Symyx Technologies for the combinatorial development of new fuel cell catalysts. Individual steps of the workflow include choice of catalyst concept, design of appropriate materials library using Library Studio [31], synthesis of electrocatalyst library on electrode array wafer, XRD and EDX characterization of individual electrocatalysts before screening, high-throughput parallel electrochemical screening of library, XRD and EDX characterization of catalysts after screening, data processing and evaluation.

The modeling and characterization of pattern dependent variations in oxide CMP further demonstrate the importance of these effects in the design of a viable CMP process. Given the magnitude of the oxide thickness variation present after planarization in comparison to the variation across the wafer as shown in Fig. 9, it is clear that process optimization should be driven by the die-level variation as much as if not more so than by the wafer-level variation. 

Flego [1] recommends the use of micro devices for automated measurement and microanalysis of high-throughput in situ characterization of catalyst properties. Murphy et al. [5] stress the importance of the development of new reactor designs. Micro reactors at Dow were described for rapid serial screening of polyolefin catalysts. De Bellefon ete al. used a similar approach in combination with a micro mixer [6], Bergh et al. [7] presented a micro fluidic 256-fold flow reactor manufactured from a silicon wafer for the ethane partial oxidation and propane ammoxidation. 

The correlation of spectroscopic data between model and real catalysts has always been a concern in catalyst characterization. Weiher et al. (2005) tried to address this issue with a cell design that was compatible with both model catalysts (e.g., submonolayer amounts of metals deposited on a silicon wafer) and real catalysts such as high-surface-area supported metals. Moreover, they also wished to have a design in which plug-flow conditions existed for the powder catalyst experiments. 

Selbrede238, published a characterization of the SiH2Cl2-WSix process in a batch reactor using an experimental design method. In comparing his results with those of Wu and Price we should keep in mind that the temperature in Selbrede s work are hot plate temperatures and that the actual wafer temperature can easily be 100°C lower in the pressure regime studied (see also chapter VII). The studied process window was ... 

The effects of the pattern density on CMP characteristics using 8-inch SKWl wafers from SKW Associates, which were specially designed for the characterization of pattern dependencies in ILD CMP, were investigated. The removal rates for various pattern densities and uniformities were evaluated and analyzed after CMP. The experimental result shows that the removal rate decreases linearly as the pattern density increases and these different removal rates for pattern densities cause bad WIDNU. It shows that a dummy pattern must be employed to minimize pattern density variation. However, the introduction of a dummy pattern may increase circuit capacitance, thus it is important to minimize the addition of dummy patterns. Therefore, to limit the removal rates across a die within reasonable values, we must determine what range of the pattern density is available in the die at the target residual thickness. Using a simple model that can take pattern density into consideration, the remaining oxide thickness was calculated and compared with the experimental data. 

To characterize the different metals mentioned earlier a test die (Eig. 9) was designed. The substrate of the die is a silicon (Si) wafer. This test die contains nine parallel tracks of the material that is under characterization. These tracks have different widths, the smallest is 1 pm and the largest is 5 pm. The other seven tracks are increments of 0.5 pm on the 1 pm track. They are all 10 mm long and the thickness of the material... 

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