Copper, structure

In the DBD region, two peaks appear, one below the (3(3-Ov Q value and one above. They are due respectively to the 60Co sum line (2505.5 keV) and the 208T1 line (2615 keV). The first is ascribed to a 60Co contamination of the copper structures due to cosmogenic... 

The Burgers vector of unit dislocations in copper is equal to the line joining the closest atoms, written a/2[110]. (a) What is the length of this vector in nanometers This dislocation is often replaced by partial dislocations [211], (b) What is the length of this vector in nanometers (The copper structure is given in Supplementary Material SI and drawn in Fig. 3.10. a = 0.3610 nm.)... 

Abstract in late 2008, soil and stream sediment orientation surveys were carried out to provide optimized field and analytical procedures for use in property and regional-scale exploration programs on MinCore s Tameapa property in Sinaloa Mexico. The property is host to two advanced mineral prospects named Pico Prieto (copper-molybdenum porphyry) and Venado (molybdenum-copper structurally controlled porphyry) that were first explored in detail by Las Cuevas during the 1970s and early 1980s. 

To date, only limited work has been reported on models for dishing and erosion in copper structures most work has been experimental in nature and report underlying pattern dependencies [13,33,51]. For example. Pan et al. [32] show experimental data based on electrical and profilometry measurements across a variety of test structures with different density, line width, and line spacing an example plot is shown in Fig. 31 where both dishing and erosion is clearly present. 

E. -i. Nakamura, S. Mori, Wherefore Art Thou Copper Structures and Reaction Mechanisms of Organocuprate Clusters in Organic Chemistry, Angew. Chem. Int. Ed. Engl. 2000, 39, 3750-3771. 

The discrepancy in the proposed reduced copper structures, along with the observation that under certain conditions both coppers of PHM are able to bind the O2 analog carbon monoxide (Cua/h only in the presence of substrate),... 

Galvanic corrosion tends to occur when two metals with different electrochemical potentials are electrically connected and exposed in an electrolyte. As a result, the less noble metal will suffer from accelerated corrosion [58]. When excess copper is polished away by copper CMP, copper and barrier metal are exposed to the CMP slurry simultaneously. Copper and barrier metal have different electrochemical potentials and thus trigger galvanic corrosion at the interface between copper and barrier metal at a certain kind of slurry composition. In this galvanic corrosion, electrons are transferred from titanium anode to copper cathode. During overpolishing of the patterned wafer, titanium near the copper structure is recessed owing to dissolution (Ti Ti -I- 2e ) and Cu " ions are preferentially deposited onto... 

Massive electrochemical attack known as galvanic corrosion [58,59] is the most severe form of copper corrosion. It can completely remove the copper from the structures (Figs. 17.25 and 17.26). It can occur when the wafers are exposed to a corrosive electrolyte for an extended period. It can also occur if the slurry does not contain enough or effective corrosion inhibitor. The source of such a galvanic potential on the patterned copper surface may be due to the fact that some copper structures connected to transistors have a different electrical potential than the rest of the wafer surface. Another possible cause of this type of galvanic potential is related to the barrier material induced metal metal battery effect. Most copper CMP slurries have been developed for Cu structures with Ta or TaN as a barrier material. In some cases, other metals may also be used in addition to the barrier metal. For example, a metal hard mask could contribute to the galvanic corrosion effects. It is also possible that some types of copper are more susceptible to corrosion that others. The grain... 

FIGURE 17.27 Copper pitting on the copper structure after Ta CMP. 

FIGURE 17.37 Very high dishing on a 100 pm square pad structure (left image). The copper in the middle of the copper structure is completely removed this copper CMP process has a very poor topography performance. On the contrary, the picture on the right shows a 200-mm wafer with SEMATECH mask 862. Only the largest 25-mm copper pad is dished down to the bottom. This copper CMP process exhibits excellent planarization performance. 

FIGURE 17.38 Ta erosion after copper CMP. The Ta in the field area at the edge of high metal density copper structures is completely removed. There is no color variation in the array of copper lines because the Ta is completely removed. This is called Ta pullback. 

FIGURE 17.49 The left image shows a 300-mm blanket wafer with massive delamination of the porous low-k film during CMP when using only 1 psi and 40 rpm. The same CMP process condition has been used on the patterned wafer in the right picture. As the picture shows, the same film behaves much better when patterned with copper structures. Only small areas of the patterned wafer present signs of delamination. 

FIGURE 17.51 The delamination occurs at the early stage of copper CMP, only after a few seconds of CMP. In the present integration scheme, the delamination occurs at the low-k interface and the low-1 capping material. The copper structure stops the cap material delamination until the end of the CMP as shown in the right image. 

In order for the copper ion to deposit onto the copper metal, an electron current must flow from the site of the titanium oxidation to the site of copper reduction. This electron transfer process is shown in Figure 4.50. The titanium metal acts as a local anode, while the copper metal acts as a local cathode. We observe this interaction to occur within a distance of approximately 20-40 pm of a copper structure and believe that this distance is limited by the conductivity of the slurry solution. The conductivity of a 1 vol% NH4OH solution is approximately 800 Q cm. 

The latter hexanuclear structural type [Fig. 20(b)] is different from the copper arenethiolate hexamers (Section II.C.5), since in these copper structures only n2-S bonded arenethiolate ligands are present, that is, the hexanuclear... 

First, it is necessary to note that the decrease of the number of holes per square millimeter surface area of the copper electrode with intensification of hydrogen evolution was very surprising. It is opposed to the already observed phenomena10,17,18 when it was shown that intensification of hydrogen evolution reaction leads to an increase of the number of holes. Thus, the unexpected development of the copper structures with intensification of the hydrogen... 

Hence, increase the temperature led to a redistribution of evolved hydrogen from those creating a honeycomb-like structure (holes formed due to the attachment of hydrogen bubbles with cauliflower-like agglomerates of copper grains between them) to those making a copper structure with the dominant presence of cauliflower-like forms and irregular channels between them. 

---