John Anthony Thomas Norman

Chemical additives for improved copper chemical vapour deposition processing

Abstract Techniques for improved copper chemical vapour deposition (CVD) processing by the addition of trimethylvinylsilane (tmvs) and hexafluoroacetylacetone (Hhfac) during copper deposition from the volatile liquid precursor Cu(hfac)(tmvs) are described. The tmvs enables stable high vaporization rates of precursor by direct liquid injection and the Hhfac permits higher deposition rates of smoother copper films. The resistivity of the copper films averages approximately 1.8 μΩcm as deposited. Combined together, these results mark an important advance toward a manufacturable copper CVD process.

Enhanced Chemical Vapor Deposition of Copper from ( hfac ) Cu ( TMVS ) Using Liquid Coinjection of TMVS

A direct liquid connection system has been applied to the chemical vapor deposition of copper using the commercially available Cu(I) precursor (hfac)Cu(TMVS), where hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate and TMVS = trimethylvinyl-silane. Precursor delivery was enhanced through the use of a coinjection system wherein additional TMVS was mixed with tire copper precursor before injection into the vaporization chamber. The results reported here demonstrate the capability of depositing blanket cooper for high purity (on the order of 99.99% copper) and low resistivity (1.85 {+-} 0.1 {mu}{Omega}-cm). These copper films have been deposited at rates up to and exceeding 1,500 {angstrom}/min. The effects of temperature and carrier gas on deposition rate and resistivity are examined. The as-deposited films demonstrate and dependence of grain size with thickness and little structural or morphological change with annealing. This study suggests that liquid coinjection is an effective method for enhancing deposition rates and for producing high quality copper films from copper(I) precursors.

New OMCVD precursors for selective copper metallization

A novel OMCVD process for the highly selective deposition of pure, adherent, low resistivity copper films onto conductive substrates is described. Central to this process is a new volatile liquid copper/sup +1/ precursor, Cupra Select, designed to thermally disproportionate at low temperatures to cleanly give copper metal and volatile non-corrosive by-products. Thus, selective depositions onto metallic versus insulating dielectric substrates are achieved between 120 to 420 degrees C with growth rates in excess of 100 nm/min and grain sizes as low as 0.1 microns. In addition, a novel complementary copper etching process is discussed that is chemically compatible with the copper CVD chemistry.<<ETX>>

MOCVD of high-k dielectrics, tantalum nitride and copper from directly injected liquid precursors

Thin films of tantalum oxide and tantalum nitride for microelectronics applications can be deposited by MOCVD using direct injection of same liquid precursors of the type R-N = Ta(NEt2)3. High-k mixed-metal oxides, such as Zr–Sn–Ti–O, metal doped TaOx and zirconium silicate, can also be deposited at relatively low temperatures from liquid mixtures as single-source precursors without solvent. This solventless CVD system is considered a more cost effective and environmentally benign process than conventional liquid injection of metal–organic precursors dissolved in organic solvents. In addition, recent advances in copper CVD precursors are reviewed. Copyright

Characterization of thin copper films grown via chemical vapor deposition using liquid coinjection of trimethylvinylsilane and (hexafluoroacetylacetonate) Cu (trimethylvinylsilane)

We have developed a technique recently for copper chemical vapor deposition utilizing direct liquid coinjection of trimethylvinylsilane (TMVS) and the copper (I) precursor (hexafluoroacetylacetonate) Cu (TMVS). We present here an investigation of the properties of copper films deposited using this technique. The films were grown on Si3N4 substrates at temperatures in the range of 220–250 °C and characterized using several experimental techniques, with an emphasis placed on factors influencing copper film resistivity. The average as‐deposited film resistivity is 1.86 μΩ cm; this value is reduced to 1.82 μΩ cm when the effects of surface scattering are taken into account. The resistivity is essentially independent of film thickness for thicknesses between 0.2 and 3.5 μm, and is reduced by less than 0.05 μΩ cm by annealing at 400–600 °C in vacuum. The total impurity content of the films is approximately 100 parts per million. The film density is 97±2% of the bulk copper value. The average grain size increase...

Reversible Complexes for the Recovery of Dioxygen

Dioxygen 1s produced 1n tonnage quantities by the distillation of air at cryogenic temperatures. In recent years, alternative technologies have emerged that employ O2- or N2-select1ve sorbents or O2-permselectlve polymer membranes. New transition metal complexes that can bind O2 reversibly and with high specificity may provide the basis for even better processes for dioxygen recovery. One of the more promising approaches 1s the use of such complexes as O2 carriers In facilitated transport Immobilized liquid membranes. The performance of the cyclidene lacunar “protected site” dioxygen complexes developed by D. Busch et al. has been evaluated 1n such membranes operating at ca. 0°C. The complexes facilitate the transport of dioxygen and result 1n O2 permeabilities and O2/N2 select1v1t1es that have been related 1n a preliminary manner to the complex concentration, equilibrium O2 binding, reaction kinetics, and carrier and O2 dlffuslvltles. While the cyclidene complexes proved to be useful in these experimental studies, for practical membranes new carriers would have to be devised that are much more stable toward oxidative degradation. The synthesis and structure of a new “protectedsite” M reversible cobalt dioxygen complex are described.

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.

New Volatile Strontium and Barium Imidazolate Complexes for the Deposition of Group 2 Metal Oxides

We report the synthesis, characterization, and experimental density function theory-derived properties of new volatile strontium and barium imidazolate complexes, which under atomic layer deposition conditions using ozone as a reagent can deposit crystalline strontium oxide at 375 °C.

New Precursors for Copper ALD

This presentation outlines the design, synthesis, properties and process capabilities of a new class of non-fluorinated proprietary volatile copper precursors created especially for ALD copper. Being volatile Cu(olefin) compounds, these new precursors are direct descendents of Air Product’s CupraSelect® copper CVD precursor (ie Cu(hfac)(tmvs)), but their chemical and physical properties set them apart from their predecessor.

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.