Surface-Treated Pads

FIGURE 5.27 Hardness as a function of PECVD-TEOS coating time [86]. 

Another type of surface-treated pads is the low-shear surface-engineered pads. When used in copper CMP, the pads exhibited vastly improved tribological performance in comparison to the untreated pads. More specifically, these pads gave a much lower COF over a larger range of Sommerfeld numbers compared to untreated pads. The reduction in shear-induced stress and its accumulation within the copper films can significantly 

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Pad-dry-cure for 3 min at 100 °C. Scheme 10.62 represents the reactive and nucleophilic sites that may exist on the surface of the treated fibre... 

The adhesion force of pad particles on the poly-Si wafer surfaces was measured in the KOH solution (pH 11) as a function of polysilicon wettability, which was varied by treating the surface with different concentrations of the oxidizer. As shown in Fig. 16.14, the adhesion force decreases and then levels... 

For simplicity, consider only one-dimensional undulations. The topography can be approximated as sinusoidal. The oxide surface profile looks like a corrugated metal roof For now consider only the die-scale undulations. The large curvature of the baseline can be treated by superposition. Assume that the mean pressure and the properties of the pad are such that the pad contacts the wafer surface without gaps. Further assume that the contact compliance is low... 

In some crude oils, high amounts of insoluble asphaltenes and inorganic solids with high surface charges (chiefly clays) will combine to form a stable solids interface pad. This interface problem is usually accompanied by poor water quality and excessive consumption of emulsion breakers. This type of interface pad is typically removed from a treating vessel by desand-desludging operations to form uneconomically treatable slop oils. Disposal costs of this slop may be high for either the oil producer or refiner. 

An intraepidermal abrasion is performed with positive keratinocyte touch . Applying an acid solution immediately after abrasion would be very painful, and a surface anesthetic must be applied with gauze pads soaked in 2% lidocaine with adrenaline (epinephrine) (with 10-15 minutes under plastic film to prevent evaporation). The anesthetic can be seen to be working as the adrenaline penetrates and causes vasoconstriction. The ETCA solution is applied carefully, and cloudy-white frosting may appear with the first coat of acid solution. As soon as cloudy-white frosting occurs, 0.5 g of post-peel mask cream should be applied per 10 cm x 10 cm of surface area treated " and the skin massaged. 

The purpose of the conditioning disk is to present the conditioning abrasive to the pad surface in a way that will deliver the necessary pad conditioning effects. Currently, all three of the required effects are treated as a single effect and handled through physical abrasion of the pad surface with a diamond-studded end-effecor (called a disk). The use of diamonds is necessary because of the extreme hardness of the abrasives used in the slurry. The presence of such abrasives on the pad would rapidly wear down materials softer than diamond. Several major suppliers of diamond conditioner disks are available, each one with its own combination of disk properties. A variety of physical disk formats is available, from solid disks to open patterns (such as ribbed or honeycomb shapes). Likewise a variety of ways to bind the diamonds to the disk exist, and they impact disk lifetimes and possibly wafer scratch damage. There is also a choice of diamond types, which affects the shape of the abrasive as it protrudes from the disk surface. 

Phaneuf et al. have developed a novel biomaterial surface that provides both localised infection resistance and haemostatic properties. Functional groups were created with woven Dacron material through exposure to ethylenediamine (C-EDA) and the antibiotic ciprofloxacin was then applied to the C-EDA using the pad/autoclave technique followed by surface immobilisation of the coagulation cascade enzyme thrombin. It was found that the antimicrobial activity of the treated fabric surface persisted for 5 days compared with the untreated fabric. Thrombin surfaces had 2.6-and 105-fold greater surface thrombin activity compared with non-specifically bound thrombin and ciprofloxacin-dyed surfaces, respectively. This study demonstrated that ciprofloxacin and thrombin can be simultaneously incorporated onto a biomaterial surface while maintaining their respective biological activities (Phaneuf et al., 2005). 

After treatment, it is also desirable to have no accumulations at the layer between the oil and the water which forms a middle phase or interface pad. A large middle phase (interface pad) would have to undergo treatment separately as it tends to collect solids, emulsifiers, asphaltenes, and other assorted surface-active impurities. On flic one hand, an interface pad presents no problem as the resolved water is drawn out from the bottom of a setting tank, or the pad may act as a filter for the mass Iransfer of sohds into the oil phase. This interface can be removed and treated separately, after oil dehydration. On flie other hand, a large pad creates slop oil and presents its own separation and disposal problems. For this reason the user is cautioned against overdosing in treatment. The choice of chemicals used is thus crucial to avoid overdosing or incompatibilities. 

Surface modified polyester fabric was padded through a two bowl vertical laboratory padder with two dips and two nips to give a wet pick up of 85 5% on the weight of the fabric with or without cross-liniking agent. After the padding, Neemazal treated PET fabric was dried at 85°C for 5 minutes and also at 130°C for 2 minutes. The fabric treated along with citric acid and BTCA was dried at 85°C for 5 minutes and simultaneously also cured at 1S0°C for 2 minutes. 

Figure 7. Surface pH on pads made mdi urease inhibitor treated cellulose fluff.

The following examples will be treated to highlight the universal applicability of mSREs for investigating CMP of Si02 and other dielectrics. The technical implementation of mSREs in the measuring system and investigafions of the oxide removal by chemical etch and CMP, characterization of slurries and surface modificafions as well as interactions with the pad are presented. 

Treatment of wool with a FWA, followed by post-treatment with thiourea/formaldehyde by a pad/cure method, confers a high level of protection against photoyellowing and also improves the initial fabric whiteness (134). Unfortunately, this process is not commercially viable, partly because of environmental concerns about thiourea and formaldehyde and also because much of the benefit is lost after laundering. An alternative approach is to physically separate the FWA from the wool fiber by incorporating the whitener into a suitable polymer that can be applied as a surface treatment to wool fabrics (135). The photostability of the treated fabrics is somewhat better than for conventional FWA treatments (being similar to bleached wool) but the initial whiteness is significantly lower than that of FWA-treated wool. 

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