Copper slurries

Metal-mediated category llae cyclizations comprise the next group of selenophene syntheses to be discussed. Dibenzoselenophenes (and dibenzotellurophenes) have been prepared from 2,2 -diiodobiphenyl derivatives <1995JOC5274>. Treatment of the biphenyl 108 with selenium-copper slurry, generated from disodium diselenide and copper(l) iodide, produced 3,7-dinitrodibenzoselenophene 109 (Equation 17). 

Another example of slurry prescreening is presented here. Three batches, lot 1 (in spec) and lots 2 and 3 (under suspicion), from a commercial copper slurry were inspected by replicating the conditions of an 8-in. Mirra polisher on a bench-top tester. The bench-top results could differentiate between the good lot 1, the faulty lot 2, and the faulty lot 3 (refer to Table 4.1 for numerical data). Verification of these results on the production polisher fully confirmed the screening data, with excellent process correlation between the production and bench-top machines. Thus, tribometrology collected on bench-top testers can be useful not only in slurry characterization but also in quality control. 

Li Y. Copper slurry developments. CMP for ULSI Multilevel Interconnection-Short Course. Marina Del Rey, CA 2003. 

Patri UB, Aksu S, Babu SV. Role of functional groups of complexing agents in copper slurries. J Electrochem Soc 2006 153(7) G650-G659. 

FIGURE 17.42 Super-shallow scratches. Some of these scratches can be below the defect detection limit. The left picture shows multiple shallow scratches using experimental slurry. It is believed that a solid form of by-product generated during the CMP process is responsible for this very high density of very shallow scratches. The right picture shows an example of an isolated scratch observed on a patterned wafer using commercial copper slurry. 

In the copper slurry formulations described below, we have attempted to maximize the solubility and dissolution rate of the copper in the slurry, and therefore dissolution of the abraded material is expected to be the dominant removal mechanism. However, the removal of the abraded material may occur as a combination of several of the above mechanisms. For example, the abraded material may initially fall into the pad undissolved, where it then dissolves. Such a scenario was described in Section 4.6.2 where it was observed that when the concentration of polish by products in the pad is high, the slurry initially turns black, indicating incomplete dissolution and the formation of copper oxide precipitates. With time, however, the slurry turns blue, indicating dissolution and the formation of the Cu(NH3)2 complex. Thus, the optimum polishing conditions may provide for a combination of removal mechanisms. 

Profilometry was performed on a wafer which was polished in 40 second time increments under baseline conditions using an experimental grade copper slurry at 4 psi on a perforated IClOOO/Suba rv pad on an IPEC 372MU. Figure 3 displays the extracted step-height-reduction as a function of trench width. Several important conclusions are immediately evident. 

A highly reactive copper slurry, prepared by the reduction of CuI PEts with 1 equiv. of lithium naph-thalide, undergoes rapid oxidative addition to alkynyl halides under mild conditions, and induces their homocoupling when oxygen is bubbled through the mixture. 

Dinitrotelluranthrene 140 has been prepared by treatment of 1,2-diiodo-4-nitrobenzene with a tellurium-copper slurry obtained in situ from disodium telluride and copper(l) iodide in A -methylpyrrolidine (NMP) (Equation 35)... 

Questions remain about how to extend the number of slurries for which flow reduction is feasible. This includes some types of copper slurries. To do this requires basic understanding of the particular properties of each slurry or class of slurries and how they affect the removal rate. For example, some copper slurries are very temperature sensitive. The SIS designs described here inject fresh slurry at room temperature and remove warm slurry that has passed under the carrier. This lowers the polishing temperature and can lower the removal rate. However, an injector bottom that retains the used slurry can (and has been) designed that can make up for the temperature deflcit and produce a favorable rate. Thus, progress in slurry reduction may be possible for one category of slurry at a time. 

In addition, there does seem to be a hazard from foliar contamination of herbage with copper-rich slurries. Price and Suttle [368] have presented evidence that copper in pig slurry is almost as available to sheep [369] as copper present as copper sulfate, and state that the main risk in applying high-copper slurry to pastures lies in the ingestion of copper as a foliar contaminant by grazing sheep. This risk can be minimised by treating cut... 

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