Electrodeposition of copper

Adhesion of copper films to PMDA/ODA polyimide was determined by peel tests conducted on samples that were prepared by vapor-depositing a thin layer of copper onto the polyimide and then building the thickness of the metal layer to about 18 p,m by electrodeposition of copper. Results of the adhesion measurements correlated well with substrate pretreatment. When the substrate... 

Electrodeposition of copper indium disulfide (CulnS2) has been reported [180-182], In a typical instance, single-phase polycrystalline CuInS2 thin films composed of 1-3 fim sized crystallites were grown on Ti by sulfurization of Cu-ln precursors prepared by sequentially electrodeposited Cu and In layers [183]. In this work, solar cells were fabricated by electrodepositing ZnSe on CuInS2. Cyclic... 

Despite the fact that the electrodeposition of copper and silver at the water-DCE and the water-dichloromethane interfaces has been generally regarded as the first experimental evidence for heterogeneous ET at externally biased ITIES [171], a very limited amount of work has dealt with this type of process. This reaction has also theoretical interest because the molecular liquid-liquid interface can be seen as an ideal substrate for electrochemical nucleation studies due to the weak interactions between the interface and the newly formed phase and the lack of preferential nucleation sites always present at metallic electrodes. 

Growth formation in epitaxial electrodeposition. Recently, Sheshadri113 observed that at small overpotentials caused by faradaic rectification, growth formation occurs in the epitaxial electrodeposition of copper on various copper single-crystal planes. 

Chiba [43] has found that the electrodeposition of copper from a cupric-EDTA bath, in the presence of ultrasound, gave increased limiting current densities and increased cathodic efficiences while at the same time reducing the grain size. Walker [44,45] has shown that deposits obtained from sulphate baths in the presence of ultrasound show increased hardness. 

Drake [35] has measured the thickness of the diffusion layer during the electrodeposition of copper from an acidic-sulphate system. He obtained a value of approximately 200 pm for the silent system and values of 34 pm and 3.4 pm for ultrasonic frequencies of 1.2 MHz and 20 kHz respectively. The corresponding values of the limiting-current density were from 8 Am (silent) to 50 A m (1.2 MHz) to 500 A m (20 kHz), indicating a significant increase in the rate of deposition. 

Figure 6.20. Current-potential relationship for electrodeposition of copper from acid CUSO4 solution. (From Ref. 53, with permission from the Electrochemical Society.)...

For example, if Qi = 50 tF/cm and R = 2 fi, t = 4.6 X 10 " s (0.46 ms). Thus, in the galvanostatic transient technique, the duration of the input current density pulse is on the order of milliseconds. From a series of measurements of for a set of i values, one can construct the current-potential relationship for an electrochemical process. For example. Figure 6.20 shows the current-potential relationship for the electrodeposition of copper from acid CUSO4 solution. 

Three-dimensional epitaxial crystallites (TECs) were observed in the first stages of electrodeposition of copper (51) and nickel (58) on copper substrates. TECs of nickel formed on copper-film substrate from nickel sulfate solutions in low concentration are shaped rectangularly with edges averaging 1300 A in length. The coherent... 

A production process has recently been implemented by IBM. The aim was to reduce the electrical resistance of the interconnects in their chip to about one-third of the values attainable using aluminum and at the same time increasing the resistance against electromigration. This was made possible by employing electrodeposition of copper in a Damascene method. The manufacturing sequence is presented in Figure 17.11. 

SUPERCONFORMAL ELECTRODEPOSITION OF COPPER INTO NANOMETER VIAS AND TRENCHES... 

The inhibition-acceleration mechanism. Moffat et al. (37) proposed the inhibition-acceleration mechanism to explain the experimentally observed comer rounding (inversion of curvature. Fig. 19 in Ref. 37) and general shape evolution in superconformal electrodeposition of copper in vias and trenches of nanometer dimensions (37,38). These authors also smdied a three-additive system composed of two inhibitors and one accelerator. They concluded that superconformal deposition and comer rounding may be attributed to competitive adsorption of inhibitor and accelerator. This model is based on the assumption of curvature (in vias and trenches) -enhanced accelerator coverage. 

Modeling. Two types of modeling were used to interpret and optimize superconformal electrodeposition of copper ... 

The identification of intermetallic compounds in electrodeposition of copper-cadmium alloys by electrochemical techniques was described [214]. 

Fig. 7.166. Macrospiral growth observed during electrodeposition of copper in the system Cu (100)/...

Crystal Growth Morphology for the Electrodeposition of Copper in the Presence and Absence of Kf mol liter-1 n-Decylamlne... 

Nanocrystalline copper with an average crystallite size of about 50nm can be obtained without additives in the ionic liquid 1-butyl-l-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP]Tf2N) [92], Because of the limited solubility of the tested copper compounds in this ionic liquid, copper cations were introduced into the ionic liquid by anodic dissolution of a sacrificial copper electrode. The electrodeposition of copper was also investigated in the ionic liquid... 

An important extension of these techniques is when the substrate is made into an electrode in a small electrochemical cell, so that the change in surface morphology of the substrate can be monitored with time. In this way, for example, direct visualisation of electrodeposition at the sub-microscopic level can be seen in real time, both nucleation and growth phases, e.g., the electrodeposition of copper in media with and without organic additives [42]. 

The electrodeposition of copper, Cu, has been studied in MPCl- [49], BPCl-... 

V, respectively [50]. The electrodeposition of copper is also possible in a basic EMICI-AICI ionic liquid [53]. 

The electrodeposition of copper, Cu, has been reported in a TMHAN(CF3S02)2 ionic liquid [104]. A divalent copper species, Cu(ll), is introduced by dissolving Cu[N(CF3S02)2l2> which is prepared by the reaction of CuO with HN(CF3S02)2-The reduction of Cu(II) to a monovalent copper species, Cu(l), occurs at around 0.6 V vs. The formation of Cu(I) is also observed by the proportionation... 

Dini JW. Electrodeposition of Copper in Modern Electroplating. 4th ed. New York John Wiley Sons, Inc. 2000. 

EVD-copper or silver was deposited at a pressure of 2.1 x 10 Pa as a preplate for electroplating. A commercial unit utilizing a tungsten basket to contain and heat the metal was used. A 150-nm-thick copper or silver layer was obtained and followed by electrodeposition of copper. 

By the process described above, a plasma film could be obtained that had high enough electrical conductivity to allow direct electrodeposition of copper. The bulk resistivity of film measured by a four-point probe was 2.6 x 10 " ohm-cm for the copper-containing polymer film when deposition was stopped after 18 min at HOW. This value is critical if a uniform electrolytic deposit is to be obtained. For safety, deposition was carried out until a total film thickness of 150nm was obtained, giving a nearly pure metallic layer thick enough to allow subsequent electroplating. 

Another aspect of the growth morphology in electrodeposition of metals is the formation of macrospirals characterized by spiral steps with a height of more than 10 nm and a step separation of more than 1 pm. Such macrospirals have been observed in various studies [5.15, 5.73). Fig. 5.37 shows an example of macrospiral growth observed during electrodeposition of copper [5.73]. 

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