Chemical Vapor Deposition Of Copper Research Articles

A review on copper chemical vapour deposition

Copper and aluminized aluminium are two of the most often utilised metals that are also in great demand owing to the diverse possibilities of each of these metals. In spite of the fact that earlier investigations have shown achievement with many different deposition processes for copper on aluminium, the method of chemical vapour deposition will serve as the primary focus of this inquiry. Copper vapour deposition using chemical vapour deposition (CVD) on aluminium may have applications in a variety of areas, including aerospace and transportation, among others. Aluminum is an excellent material for use as a substrate because, after being deposited, it can be chemically etched; this enables its removal from complicated surfaces to be accomplished with relative ease. Because of its qualities, aluminium is in a class all by itself when it comes to serving as a substrate. This article presents a review of various methods for copper chemical vapour deposition.

Engineering Copper Adhesion on Poly-Epoxy Surfaces Allows One-Pot Metallization of Polymer Composite Telecommunication Waveguides

Mass gain in the aerospace sector is highly demandable for energy savings and operational efficiency. Replacement of metal parts by polymer composites meets this prerequisite, provided the targeted functional properties are recovered. In the present contribution, we propose two innovative and scalable processes for the metallization of the internal faces of carbon fiber reinforced polymer radiofrequency waveguides foreseen for implementation in telecommunications satellites. They involve sequential direct liquid injection metalorganic chemical vapor deposition of copper and cobalt. The use of ozone pretreatment of the polymer surface prior deposition, or of cost effective anhydrous dimethoxyethane as solvent for the injection of the copper precursor, yield strongly adherent, 5 µm Cu films on the polymer composite. Their electrical resistivity is in the 4.1–5.0 μΩ·cm range, and they sustain thermal cycling between −175 °C and +170 °C. Such homogeneous and conformal films can be obtained at temperatures as low as 115 °C. Demonstration is achieved on a polymer composite waveguide, composed of metallized 60-mm long straight sections and of E-plane and H-plane elbows, that paves the way towards the metallization of scale one devices.

Formic acid and formate salts for chemical vapor deposition of copper on glass substrates at atmospheric pressure

Deposition of copper on glass slides is obtained at atmospheric pressure using copper microparticles and formic acid or copper formate.

Decomposition Schemes of Copper(I) <I>N</I>,<I>N</I>′-Diisopropylacetamidinate During Chemical Vapor Deposition of Copper

Copper(I) N,N'-diisopropylacetamidinate [Cu(amd)]2 (amd = CH(CH3)2NC(CH3)NCH(CH3)2), an oxygen and halogen-free compound, was previously tested as precursor for pure copper CVD and ALD films. The present work deals with the investigation of the composition and of the reactivity of the gas phase during the CVD process. The work was performed by mass spectrometry as a function of temperature in two different, though complementary environments: (A) in a miniature, low pressure hot wall CVD reactor, (B) in a cold wall reactor operating at subatmospheric pressure. (A) revealed that the onset of thermal decomposition is 140 degrees C and 130 degrees C in vacuum and in the presence of hydrogen, respectively; maximal decomposition degree is reached at temperature higher than 200 degrees C. The protonated ligand H(amd) is the main gaseous decomposition by-product; propene CH2=CHCH3, acetonitryle CH3C[triple bond]N and iminopropane CH3C(CH3)=NH are also observed in vacuum. Heterogeneous decomposition mechanism both in vacuum and hydrogen presence is discussed.

Investigation of Thermal and Hot-Wire Chemical Vapor Deposition Copper Thin Films on TiN Substrates Using CupraSelect<SUP>®</SUP> as Precursor

Copper films were deposited on oxidized Si substrates covered with TiN using a novel chemical vapor deposition reactor in which reactions were assisted by a heated tungsten filament (hot-wire CVD, HWCVD). Liquid at room temperature hexafluoroacetylacetonate Cu(I) trimethylvinylsilane (CupraSelect) was directly injected into the reactor with the aid of a direct-liquid injection (DLI) system using N2 as carrier gas. The deposition rates of HWCVD Cu films obtained on TiN covered substrates were found to increase with filament temperature (65 and 170 degrees C were tested). The resistivities of HWCVD Cu films were found to be higher than for thermally grown films due to the possible presence of impurities into the Cu films from the incomplete dissociation of the precursor and W impurities caused by the presence of the filament. For HWCVD films grown at a filament temperature of 170 degrees C, smaller grains are formed than at 65 degrees C as shown from the taken SEM micrographs. XRD diffractograms taken on Cu films deposited on TiN could not reveal the presence of W compounds originating from the filament because the relative peak was masked by the TiN [112] peak.

Filling Narrow Trenches by Iodine-Catalyzed CVD of Copper and Manganese on Manganese Nitride Barrier/Adhesion Layers

We present a process for the void-free filling of sub-100 nm trenches with copper or copper-manganese alloy by chemical vapor deposition (CVD). Conformally deposited manganese nitride serves as an underlayer that initially chemisorbs iodine. CVD of copper or copper-manganese alloy releases the adsorbed iodine atoms from the surface of the manganese nitride, allowing iodine to act as a surfactant catalyst floating on the surface of the growing copper layer. The iodine increases the growth rate of the copper and manganese by an order of magnitude. As the iodine concentrates near the narrowing bottoms of features, void-free, bottom-up filling of CVD of pure copper or copper-manganese alloy is achieved in trenches narrower than 30 nm with aspect ratios up to at least 5:1. The manganese nitride films also show barrier properties against copper diffusion and enhance adhesion between copper and dielectric insulators. During post-deposition annealing, manganese in the alloy diffuses out from copper through the grain boundaries and forms a self-aligned layer that further improves adhesion and barrier properties at the copper/insulator interface. This process provides nanoscale interconnects for microelectronic devices with higher speeds and longer lifetimes.

Evaluation of a novel unfluorinated copper precursor for chemical vapor deposition

A kinetics of the chemical vapor deposition (CVD) of copper using novel unfluorinated precursor, copper(I)(N(1(dimethylvinylsiloxy)-1-methylethano)-2-imino-4-pentanoate), namely Cu-KI5, was studied. Since its great thermal stability, Cu-KI5 allowed high source temperature to provide high vapor pressure, for example Cu-KI5 has a vapor pressure of 0.2–2.2 Torr at the temperature range of 100–140 °C. Furthermore, copper could be deposited by direct reduction from Cu-KI5 instead of disproportionation. By using formic acid (HCOOH) as a reducing agent, copper films were deposited on ruthenium substrate at temperature range of 150–350 °C. The activation energy was 48.9 kJ/mol in surface reaction limited region (<210 °C) and 1.9 kJ/mol in diffusion limited region (>210 °C) at the total pressure of 5 Torr. Secondary ion mass spectroscopy (SIMS) analysis showed that CVD copper film of high purity (>99.99%) was deposited at 250 °C. The as-deposited copper films grown at 150–300 °C exhibited strong 〈111〉 preferred orientation. The minimum resistivity of the copper film was 1.77 μΩ cm obtained at the deposition temperature of 250 °C. In the surface reaction limited region, kinetic data extracted from experiments enabled 2-D computational simulation to predict copper deposition into trench structures. Simulation results showed excellent step coverage, which was larger than 90% for aspect ratio of 10:1. Cu-KI5 is a promising Cu-CVD precursor for the fabrication of ultra large scale integration (ULSI) or through silicon via (TSV) copper interconnects.

The Effect of Plasma Treatment on Adsorbed Iodine as a Catalyst in Chemical Vapor Deposition of Copper and Application to Filling of Deep Trenches with High Aspect Ratios

Plasma treatment was introduced in order to control the catalytic properties of iodine in catalyst-enhanced chemical vapor deposition (CECVD) of copper (Cu). The iodine adatoms are deactivated (i.e., lose their catalytic effect) by forming Cu–I bonds through reaction with Cu atoms by the bombardment of ions during the plasma treatment. The surface concentration of effective iodine adatoms that can act as catalysts decreases exponentially with an increasing of ion exposure which is the product of ion flux and plasma treatment time. The deactivated iodine can be reactivated by annealing above 200 °C. The enhancement factor, defined as the ratio of the enhanced deposition rate of Cu film by the adsorbed iodine to the deposition rate without the catalytic effect of iodine, is proportional to the surface concentration of effective iodine adatoms. The distribution of the surface concentration of effective iodine adatoms inside the trench can be controlled by the plasma treatment. CECVD coupled with plasma treatment enables void-free filling of deep trenches with an aspect ratio of 14.

Chemical vapor deposition of copper oxide films and entangled quasi-1D nanoarchitectures as innovative gas sensors

Supported copper oxide nanosystems were synthesized by chemical vapor deposition (CVD) on Al2O3 substrates and characterized by means of glancing incidence X-ray diffraction (GIXRD), secondary ion mass spectrometry (SIMS) and field emission scanning electron microscopy (FESEM). The analyses showed an evolution from polycrystalline Cu2O nanodeposits to CuO samples with an entangled quasi-1D morphology upon increasing the growth temperature from 350 to 550°C. For the first time, the sensing properties of CVD copper oxide nanosystems were probed in the detection of volatile organic compounds (VOCs; e.g. CH3COCH3, CH3CH2OH). The obtained results revealed good responses even at moderate operating temperatures, with characteristics directly dependent on the system composition and nano-organization.

In situ functionalized self-assembled monolayer surfaces for selective chemical vapor deposition of copper

Recent studies show that the self-assembled monolayer (SAM) is well suited to control the selectivity of chemical vapor deposition (CVD). Here, we reported the selective CVD for copper on the functionalized SAM surfaces (with –SH, –SS–, and –SO3H terminal groups). The –SS– and –SO3H terminal group surfaces were obtained through in situ chemical transformation of –SH terminal group surface of a 3-mercaptopropyltrimethoxysilane-SAM (MPTMS-SAM). As a result, the –SS– terminal group surface reduces copper deposition and the –SO3H terminal group surface enhances copper deposition comparing to the –SH terminal group surface. In addition, the MPTMS-SAM was irradiated by UV-light through a photo mask to prepare SH-group and OH-group regions. Then, copper films were deposited only on the SH-group region of the substrate in chemical vapor deposition. Finally, patterns of copper films were formed in the way of UV-light irradiation. These results are expected for use of selective deposition of copper metallization patterns in IC manufacturing processes.

Effects of amino-terminated self-assembled monolayers on nucleation and growth of chemical vapor-deposited copper films

Copper films were grown on clean Si, SiO 2 and 3-amino-propyl-trimethoxy-silane (APTMS) self-assembled monolayers (SAMs)-modified SiO 2 substrates via chemical vapor deposition (CVD) and were examined using scanning electron microscopy, atomic force microscopy, and X-ray diffraction (XRD). Ordered APTMS-SAMs obtained from a 3 mM concentration solution were found to enhance adhesion of the films on the SiO 2 substrate surface. However, in 60 mM solution, APTMS layers tended to be multilayered and formed islands via self-polymerization. Copper nucleation on APTMS-SAMs modified substrate surfaces occurs more easily than on the clean Si and SiO 2 substrate surfaces. Enhanced copper CVD was ascribed to the interaction of Cu atoms with the N-containing terminal groups of APTMS-SAMs. The XRD analysis showed that the copper thin films deposited on the APTMS-modified SiO 2 substrates have a structure with (111) preferred orientation, which is known to have a good electromigration resistance.

Microstructure and electrical properties of Cu films obtained by chemical vapor deposition of copper(I) pentafluoropropionate complexes with vinyltrialkylsilanes

Copper thin layers were deposited on Si(111) and glass substrates by chemical vapor deposition method using [Cu(OOCC 2F 5)(L)], L = vinyltrimethylsilane ( 1), vinyltriethylsilane ( 2) as precursors. Application of multistage depositions of Cu films on a glass surfaces resulted in formation of the metallic membranes. Fabricated crystalline copper layers, which contains some carbon (5–9%) and oxygen (1–5%) impurities, have been characterized by grazing incidence X-ray diffraction and X-ray photoelectron methods. The morphology studies exhibited metallic layers composed of copper grains, their size and packed density depends on deposition parameters. Electrical properties of metallic films were studied by four-point probe, as a function of temperature in 103–333 K range.

Modification by UV-light irradiation of the affinity for copper chemical vapour deposition of self-assembled monolayers of organosilanes on SiO 2 substrates

Self-assembled monolayers (SAMs) of (3-mercaptopropyl)trimethoxysilane (MPTMS) [HS-(CH 2) 3-Si-(OCH 3) 3] were deposited by vapour phase silylation onto SiO 2 substrates. After UV-light irradiation in air, the SAMs exhibit enhanced affinity for copper (Cu) chemical vapour deposition (CVD) (performed by using the precursor (MHY)Cu(hfac) where MHY = 2-methyl-1-hexene-3-yne and hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate) as compared to unirradiated ones, due to oxidation of the thiol head group (–SH) and conversion to sulphonate (–SO 3H), thus demonstrating selective Cu CVD. This is confirmed by X-ray Photoelectron Spectroscopy (XPS) measurements performed also on SAMs which were chemically oxidized in hydrogen peroxide (H 2O 2) or nitric acid (HNO 3) solutions. A positive image of the grid mask used for irradiation is formed by the Cu film onto SAMs which were previously irradiated in air. A negative image is formed onto SAMs which were irradiated under controlled atmosphere of nitrogen or argon gas with better selectivity obtained when irradiation was performed through an optical filter which blocks the 184.9 nm line of the light.

Copper metallization based on direct-liquid-injection hot-wire CVD

It is presented for the first time a direct-liquid-injection hot-wire CVD system for copper chemical vapor deposition using hexafluoroacetylacetonate Cu(I) trimethylvinylsilane as precursor. The system enables: (a) the selective chemical vapor deposition (SCVD) and (b) the deposition of hot-wire CVD (HWCVD) copper films. Moreover, it enables the deposition of tungsten oxide films, which adhere well on the oxidized Si substrates, by heating the tungsten filament only in a hydrogen-containing ambient (hwHWO films). Cu films were selectively deposited (SCVD) on patterned hwHWO layers but these deposits were large-grained and had a very high electrical resistance. This effect was attributed to the semi-insulating nature of hwHWO films, which implies the presence of few free electrons on their surface necessary for the easy decomposition of the precursor molecules. Cu was SCVD on patterned hwHWO/HWCVD Cu “sandwiches” giving patterns with fine grains and electrical resistivity near that of the bulk metal.

In Situ Observation of Initial Nucleation and Growth of Chemical Vapor Deposition of Copper by Surface Reflectivity Measurement

Initial nucleation and growth of Cu thin films on a Ta substrate via chemical vapor deposition (Cu-CVD) for ultra large scale integration (ULSI) interconnects is monitored in situ by irradiating the substrate surface with 635-nm-wavelength laser light and then measuring the change in reflected-light intensity. The effect of injection of water vapor during deposition on initial nucleation and growth is investigated by using X-ray photoelectron spectroscopy (XPS) to measure the surface chemical state of the Ta substrate. Results show that water-vapor injection during Cu-CVD enhances both the nucleation and growth of Cu by introducing adsorbed OH groups onto the substrate surface and yields a smooth, continuous surface morphology. The optimal time at which to inject water vapor before and/or during deposition is also determined using our in situ monitoring technique.

Chemistry of Cu deposition by Cu(hfac)(tmvs) monitored by Li+ ion attachment mass spectrometry

Ion attachment mass spectrometry was used for continuous in situ analysis of coordinated products formed during copper chemical vapor deposition (Cu CVD) by Cu(1,1,1,5,5,5-hexafluoroacetylacetonate)(vinyltrimethylsilane) [Cu(hfac)(tmvs)] in a simple tubular reactor. This study of the thermally labile Cu(hfac)(tmvs) demonstrated the utility of this method for detecting molecular ions of labile compounds. The results demonstrate the feasibility of monitoring the deposition chemistry of Cu(hfac)(tmvs) by generating Li+ adduct molecular ions by means of the Li+ ion attachment technique. The reaction pathways for Cu CVD by Cu(hfac)(tmvs) were studied by analysis of the reaction products. H(hfac) and tmvs were identified as the main products when Cu(hfac)tmvs was heated at temperatures ranging from room temperature to 160°C in the reactor. The rate constant for Cu deposition, k (1∕s), was determined to be 1.6×106exp(−10.2kcal∕molRt).

Detection of Cu(hfac)(tmvs) by Li + ion attachment mass spectrometry

Li + ion attachment mass spectrometry was used to detect Cu(1,1,1,5,5,5-hexafluoroacetylacetonate)(vinyltrimethylsilane) [Cu(hfac)(tmvs)], a thermally labile precursor used in copper chemical vapor deposition (Cu-CVD), with the intent of developing improved methods for mass-spectrometric analysis of the CVD process. A uniquely designed quadrupole mass spectrometry (QMS) system coupled with a Li + ion emitter and a laboratory-built direct introduction system of the sample provided the molecular ion of Cu(hfac)(tmvs) as the Li + ion adduct for the first time. The use of this system demonstrates the feasibility of generating Li + ion adduct for real-time monitoring of products encountered in Cu-CVD process facilities.

Plasma-Enhanced Atomic Layer Deposition of Ru–TiN Thin Films for Copper Diffusion Barrier Metals

Ruthenium-titanium nitride (Ru–TiN) thin films were grown by plasma-enhanced atomic layer deposition (PEALD) at a growth temperature of . For the Ru–TiN PEALD, Ru and TiN were sequentially deposited to intermix TiN with Ru. The composition of Ru–TiN films was controlled by changing the number of deposition cycles allocated to Ru, while the number of deposition cycles for TiN was fixed to one cycle. The microstructures of Ru–TiN films changed from polycrystalline to amorphous, as the intermixing ratio of Ru increased in the deposited Ru–TiN films. The resistivity of the Ru–TiN film was abruptly increased by adding Ru at the first stage, but after showing a peak resistivity, it decreased with the intermixing ratio of Ru in the films. Especially, the film of showed an electrical resistivity of . As a Cu diffusion barrier layer, amorphous Ru–TiN films showed a superior copper diffusion barrier property to TiN or Ru itself, which had a polycrystalline structure. Moreover, Ru–TiN films showed a good adhesion to both chemical vapor deposition copper and an underlayer of .

Kinetics of Copper CVD Using Solution Delivery of Cu ( hfac ) 2 and Isopropanol

We have measured the growth kinetics and film properties for copper chemical vapor deposition (CVD) using dissolved in isopropanol as the precursor delivery method. Growth rates are similar to those reported using reactant evaporation as the delivery method, despite operating with a much lower partial pressure of in the reactor. The reaction kinetics are first-order with respect to precursor partial pressure and zero-order with respect to isopropanol. Film morphology suggests that growth occurs via three-dimensional cluster formation (i.e., a Volmer–Weber process). Resistivity deviates above the bulk value for films thinner than and may be attributed mainly to electron scattering from surface roughness. We propose a minimal parameter series reaction mechanism that can account for the present kinetic behavior, as well as previous results using higher precursor partial pressure.

Mechanism of copper chemical vapor deposition from copper dipivaloylmethanate in hydrogen

Mechanism of copper chemical vapor deposition from copper dipivaloylmethanate in hydrogen