The corrosion behavior of electrochemically deposited copper thin films in deaerated and non-deaerated commercial cleaning solutions containing HF was investigated. Potentiodynamic polarization experiments were carried out to determine active, activepassive, passive, and transpassive regions. Corrosion rates were calculated from Tafel slopes. The addition of hydrogen peroxide to the solution and its influence on corrosion was also investigated by employing inductively coupled plasma-mass spectroscopy ͑ICP-MS͒ and X-ray photoelectron spectroscopy ͑XPS͒. The ICP-MS and potentiodynamic methods yielded comparable Cu dissolution rates. Surface analysis using atomic force microscopy and scanning electron microscopy, performed before and after the cleaning solution treatment, did not reveal any indication of pitting corrosion. The presence of hydrogen peroxide in the cleaning solution led to more than an order of magnitude suppression of copper dissolution rate. We ascribe this phenomenon to the formation of interfacial CuO detected by XPS on the wafer surface that dissolves at a slower rate in dilute HF.In the advanced interconnect systems of today, copper is the choice of metallization for ultralarge-scale integration ͑ULSI͒. Copper wiring is now employed in all interconnect layers with up to 12 metallization levels in advanced microprocessors. In principle, interconnects are electrical paths or charge carriers made out of metal lines and are separated by insulating interlayer dielectric ͑ILD͒ material. The replacement of aluminum alloys by copper mandated prominent changes in integration, metallization, and patterning process technologies. For instance, the introduction of copper in semiconductor devices has brought attention to the phenomena of thinfilm corrosion that must be circumvented for optimal device performance, reliability, and longevity. This has also mandated the adoption of wet etch clean chemistries that are Cu-compatible for the integration of dual damascene ͑DD͒ patterning of copper interconnects. A simple two-layer DD interconnect system is illustrated in Fig. 1. In such a system, the electrical signal that allows transistors to communicate with one another and with the outside world is transmitted through the metal lines within any given metallization level and through copper-filled vias from one metallization level to another. In DD integration, the via resistance is mainly determined by the via diameter and thickness, the resistivity of the copper diffusion barrier ͑DB͒ being used, and the overall interfacial resistance with the underlying metal layer. Etch residues resulting from plasma etch during patterning process steps may give rise to a high via resistance or even create openings.There have been many approaches explored to remove the plasma etch residues. These include the use of O 2 , NF 3 /Ar, and He/H 2 plasma chemistries to clean polymeric residues, 1-5 as well as the use of wet etch chemistries such as aqueous dilute HF 6 and a variety of aqueous solutions, 7 aqueous solutions containin...

As multistep, multilayer processing in semiconductor industry becomes more complex, the role of cleaning solutions and etching chemistries are becoming important in enhancing yield and in reducing defects. This thesis demonstrates successful formulations that exhibit copper and tungsten compatibility, and are capable of Inter Layer Dielectric (ILD) cleaning and selective Ti etching.

The corrosion behavior of electrochemically deposited copper thin films in deaerated and non-deaerated commercial cleaning solution containing HF has been investigated. Thin-film copper dissolution and reaction kinetics were investigated by monitoring Cu 2+ , employing inductively coupled plasma-mass spectroscopy, and the oxidation states of copper on Si wafer surface, employing X-ray photoelectron spectroscopy. It was determined that the reaction kinetics is first order with respect to both HF and oxygen concentrations. A kinetic scheme involving reduction of oxygen and oxidation of Cu 0 and Cu 1+ is proposed, which is consistent with the experimentally determined reaction kinetic orders and the observed deposition of undesired copper residues on semiconductor wafers during the cleaning process.