Copper, electroplating

Roughness has important implications in wetting applications. While the eutectic solder, SnPb, normally forms a contact angle of 15-20° with copper, it completely wets the surface of rough electroplated copper and forms a fractal spreading front [69]. 

Borgford, and Julie B. Ealy, "Electroplating Copper," Chemical... 

FIGURE 10.2 Surface topography of an electroplated copper film. 

Conventional CMP typically requires an overburden of copper of at least 4000 A due to low planarization efficiency. An overburden of 1000 A is sufficient for ECMP to achieve planarization without compromising performance in terms of dishing, erosion, and defectivity. A stress migration test was carried out at 250 °C for 333 h on a structure with metal level 1 and level 2 lines with thickness in the range of 0.14-0.16 pm. An increase in resistance by more than 10% is considered a fail. The reduction in electroplated copper thickness can reduce the number of fails in stress migration test as shown in Table 11.1. 

TABLE 11.1 Stress Migration Fails as a Function of Electroplated Copper Thickness. 

FIGURE 15.12 Schematic representation of common feature-scale nonplanarities arising from damascene patterning electroplated copper into silicon dioxide trenches (from Ref 98). 

K. K. Chakravorty, C. P. Chien, J. M. Cech, M. H. Thnielian, and P. L. Young, High-Density Interconnection Using Photosensitive Polyimide and Electroplated Copper Conductor Lines, IEEE Comp., Hybrids., Manuf. Technol., 13, No. 1, pp. 200-206 (1990). 

J. J. Barrett, High Definition Electroplated Copper Conductors on Silicon and Ceramic, Proceedings of the 5th International Microelectronics Conference, International Society of Hybrid Microelectronics, Tokyo, Japan (May 25-27, 1988), pp. 461-467. 

IMPACT OF LOW-TEMPERATURE ANNEALS OF ELECTROPLATED COPPER FILMS ON COPPER CMP REMOVAL RATES... 

Unpattemed electroplated copper wafers were polished using an IPEC 472 polisher equipped with an IR temperature sensor which measures pad surface temperature. The copper rate was determined from copper thickness measurements from a Tencor RS55 resistance monitor, calibrated to cross-sectional SEM micrographs. The SEM tools are regularly calibrated to national standards. 

Use Nickel brightener in electroplating, copper pickling inhibitor, corrosion inhibitor in aerosol cans. 

Use Electroplating copper on iron, intermediate (introduction of the cyanide group in place of the amino radical in aromatic organic compounds). 

The thin layer of tin on tin-plated steel cans is less easily oxidized than iron, and it protects the steel underneath from corrosion. It is deposited either by dipping the can into molten tin or by electroplating. Copper is also less active than iron (see Table 21-2). It is sometimes deposited by electroplating to protect metals when food is not involved. Whenever the layer of tin or copper is breached, the iron beneath it corrodes even more rapidly than it would without the coating, because of the adverse electrochemical cell that is set up. 

Stampfl, J. Leitgeb, R. Cheng, Y.-L. Prinz, F.B. Electro-discharge machining of mesoscopic parts with electroplated copper and hot-pressed silver tungsten electrodes. J. Micromech. Microeng. 2000, 10, 1-6. 

C. Cabral, P. C. Andricacos, L. Gignas, I. C. Noyan, K. P. Rodbell, T. M. Shaw, R. Rosenburg and J. M. E. Harper, Room Temperature Evolution of Microstructure and Resistivity in Electroplated Copper Films , Advanced Metallization and Interconnect Systems for ULSI Applications in 1998, Colorado Springs, CO, 1998. 

Dopant incorporation and resistance transients in unpatterned films of electroplated copper were studied as a function of bath age and other plating parameters such as current density, agitation, temperature, additive concentration and chloride concentration. Dopant content exhibits a strong dependence on agitation and additive concentration it also depends on current density but to a lesser extent. Chlorine content of the film is independent of chloride content in the bath. Dopant incorporation is independent of bath age. Resistance transients are slower the higher the dopant content of the film. 

Measurements of Rs transients were conducted in order to assess the effect of dopants / plating parameters on the kinetics of the transformation of electroplated copper [8]. Results are shown in Figure 6. For a constant bath temperature, the parameters that affect dopant incorporation the most are current density, rotation speed, and additive concentration. It is seen that an increase in additive concentration and rotation speed leads to a delay in the resistance transformation and to an increase in dopant content. Similarly, an increase in plating current density causes an acceleration of the resistance transformation and a decrease in dopant incorporation. It is thus concluded that dopant content increase causes delays in the resistance transformation of plated copper in accordance with the observations of Harper et al [8]. Results shown in Figs. 7 and 8 corresponding to different bath temperatures as well as plating from three different commercial chemistries are consistent with this correlation. 

Copper(l) potassium cyanide Cuprate(l-), dicyano-, potassium Cuprous potassium cyanide EINECS 237-192-2 Potassium copper(i) cyanide Potassium cuprocyanide Potassium dicyanocuprate Potassium dicyanocuprate(l-) UN1679. A double cyanide of potassium and copper used in electroplating copper and brass. Prisms d = 2.38 insoluble In H2O, soluble In DMSO. 

Because flux is such a concern, one contractor is exploring ultrasonic bonding (10) using prepunched aluminum interconnects that are attached to electroplated copper cell metallization with a seam welder. Others are examining fluxless bonding concepts, such as vapor-phase solder reflow. 

Chemically deposited and electroplated copper with a radial, coating thickness of 0.003 to 0.001 in. has no effect upon the transition current for the wire at a given field. The enhanced stability of a copper-coated wire after a transition has occurred has been demonstrated by producing a condition in which the tip of a hairpin of wire has undergone a transition and the normal region has not propagated from the tip along the sides of the specimen. 

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