Stephen Mark Fine

Organometallic Chemical Vapor Deposition of Copper from a New Organometallic Precursor

Thin copper films have been grown on a variety of substrates using Cu(nona-F) 2 , (bis[4-(2,2,2-trifluoroethyl)imino-1,1,1,5,5,5-hexafluoro-2-pentanonato] copper(II)), a new volatile organometallic copper precursor, and the results are compared with those obtained using copper(II) betadiketonates. Copper films were grown in a cold wall reactor at reduced pressure at temperatures between 270°C and 350°C. For Cu(nona-F) 2 , films which are pure as determined by Auger electron spectroscopy and have a resistivity of 2.1 micro-ohm cm were deposited at temperatures above 270°C, 40°C lower than was possible using Cu(hfac) 2 . At low deposition temperatures, Cu(nona-F) 2 shows some selectivity towards silicon oxide surfaces in preference to metals. The effects of CVD process parameters on the deposition rate and microstructure of the films were studied with a designed experiment and were statistically modeled. Deposition rates up to 70 nm/min were measured. The standard enthalpy of vaporization of Cu(nona-F) 2 was found to be 9.6 kcal/mol.

Consecutive Selective Chemical Vapor Deposition of Copper and Aluminum from Organometallic Precursors

For the next generation of integrated microcircuits, there exists a need in the electronics industry for high conductivity, electromigration resistant metallization that can be deposited selectivity by chemical vapor deposition techniques. This paper describes a new process for depositing copper/aluminum metallization selectively onto diffusion barrier surfaces in two consecutive steps. First copper is selectively deposited by OMCVD ontoa patterned diffusion barrier surface using a Cu(I)(hfac)(olefin) precursor. Selective copper deposition onto tungsten or titanium nitride is achieved at 150°C and 100 mtorr. Aluminum is then selectively deposited onto copper using trimethylaminealane as the OMCVDprecursor. Trimethylaminealane gives good selectivity for aluminum deposition onto coppersurfaces over a temperature range of 100–120°C without the use of a surface activating agent. A small amount of copper diffuses into the as deposited aluminum layer atthe low deposition temperature. Complete diffusion of copper into aluminum is achieved by a rapid thermal anneal at a higher temperature. The selectivity of aluminum deposition onto copper surfaces is far superior to that observed for aluminum deposition onto other metal surfaces.

A process for removing moisture from metal surfaces and inhibiting water from readsorbing using organosilanes

Summary form only given. The storage of ultra-high purity (UHP) gases is a critical issue to the electronics industry. To prepare a storage vessel or delivery manifold for ultra-high purity gas service, all the atmospheric contaminants must be thoroughly removed from the system. Of these contaminants, atmospheric moisture is the most difficult to remove. It readily condenses on metal surfaces in multiple layers with a large heat adsorption. Typically, moisture is removed by purging or evacuation for long periods of time. In some cases it takes several weeks to adequately remove moisture from a delivery system. This is an expensive, time consuming process. Sometimes systems are heated to high temperature to reduce the time required to remove moisture. However, heating is not always practical, and it does nothing to prevent re-adsorption of water if the system is again exposed to ambient atmosphere. In many cases, moisture is the critical contaminant in the gas delivery system. This is especially true when the ultra-high purity gas is corrosive. Gases such as hydrogen chloride, hydrogen bromide, fluorine, tungsten hexafluoride and other halogen containing gases will severely corrode many metals if moisture is present. Corrosion of the storage vessel or delivery manifold can result in introduction of particle or gas-phase impurities into the ultra-high purity gas, or in extreme cases, result in failure of the system. Components such as valves, regulators, and mass now controllers are very susceptible to failure due to corrosion and frequently need to be replaced. This paper describes a new method for rapidly removing moisture from metal surfaces used in the packaging and delivery of high purity bulk and corrosive-speciality gases. Furthermore, the process passivates the metal by forming a hydrophobic surface that prevents water from readsorbing. Reagents of the type RsiXYZ where R is an alkyl group and at least one of X, Y, or Z is a hydrolyzable group are shown to enhance the removal of surface adsorbed moisture and gaseous product (HX). The HX by-product and unreacted RsiXYZ are rapidly and completely purged from the system. Since water is removed from the surface by chemical reaction rather than by simple purging, the initial dry down is faster. In addition to removing adsorbed water, the treatment incorporates a stable organosilicon group into the surface which greatly reduces the polar character associated with the OH terminated surface. The treated surface is hydrophobic inhibiting water from re-adsorbing during a subsequent moisture exposure. Stainless steel surfaces passivated in this manner are shown to have improved corrosion resistance compared to unpassivated stainless steel.