KR20080002912A - Ruthenium-based materials and ruthenium alloys - Google Patents

Abstract

An alloy for use in vapor deposition or atomic layer deposition is described herein that includes ruthenium and at least one element from group IV, V or VI of the Periodic Chart of the Elements or a combination thereof. In addition, a layered material is described herein that comprises at least one layer that includes a ruthenium-based material or ruthenium-based alloy and at least one layer that includes at least one element from group IV, V or VI of the Periodic Chart of the Elements or a combination thereof.

Description

Ruthenium-based materials and ruthenium alloys {RUTHENIUM-BASED MATERIALS AND RUTHENIUM ALLOYS}

FIELD OF THE INVENTION The present invention relates to ruthenium-based materials and / or ruthenium alloys, and is a film and layered material used and / or formed from vapor deposition and atomic layer deposition.

Electronic and semiconductor components are used in ever-increasing consumer and commercial electronics, telecommunications and data exchange products. Examples of these consumer and commercial products are televisions, computers, cell phones, pagers, palm-type or portable organizers, portable radios, car stereos, or remote controls. As the demand for these consumer goods and commercial electronics increases, there is a need for the same smaller and more portable products for consumers and businesses.

As a result of the reduced size of these products, the components that make up the product must also be smaller and / or thinner. Examples of these components that need to be reduced or reduced in size include microchip interconnections, semiconductor chip components, resistors, capacitors, printed circuits or wiring boards, wiring, keyboards, touch pads, and chip packaging. to be.

As the size of electronic and semiconductor parts is reduced or reduced, some of the defects present in the larger parts will be larger than in the reduced parts. Therefore, defects that may or may be present in larger parts should be identified and corrected as much as possible before the parts are reduced for smaller electronics.

In order to identify and correct defects in electronic components, semiconductor components, and communication components, the components, materials used, and the manufacturing process for manufacturing these components must be disassembled and analyzed. Electronic components, semiconductor components and communication / data exchange components are in some cases composed of layers of materials such as metals, metal alloys, ceramics, inorganic materials, polymers, or organometallic materials. Most material layers are thin (thickness less than tens of angstroms). In order to improve the quality of the material layer, layer formation processes such as, for example, physical vapor deposition of metals or other compounds, should be evaluated, if possible, corrected and improved.

The increasing demand for microprocessor speeds facilitates the transition from aluminum to copper-based interconnects, ie, reduces the electrical resistance of the circuit. One obstacle in copper (Cu) interconnects is copper diffusion to the substrate. Typically, TaN / Ta or TaN / Ta or TiN / Ti bilayer barrier films are used for copper diffusion barriers in microelectronic circuit fabrication. One of the drawbacks of this barrier design is the inability to direct-electroplate copper over Ta or Ti. Thus, a copper-seed film is placed on the barrier film by physical vapor deposition (PVD) to facilitate copper electro-chemical plating (ECP). However, as the feature size in the interconnects becomes smaller, the composite thickness of the barrier / copper-seed layer becomes significantly thicker than the via / trench size. Recently, ruthenium has proven to be a potential barrier material because copper can be plated on Ru without a PVD copper seed layer.

Although Ru has a very good barrier strength, it can be seen that the adhesion in the substrate layers Si and SiO2 is unacceptably poor. For example, ruthenium has a Ru—O bond strength of 43 Kcal / mol relative to 152 Kcal / mol; TiO has 168 Kcal / mol or TaO has 198 Kcal / mol. Adhesion is one of the most important factors in microelectronic interconnects, and incompletely bonded interfaces often increase the likelihood of device defects, especially these defects are the result of stress and electron transfer. In the past, Ru [1-3], Ru-RuO ₂ [4], and RuTiN-RuTiO [5] have been proposed as diffusion barriers. However, this approach was not attempted by rigorous adhesion tests.

Therefore, it would be ideal to develop ruthenium-based materials and ruthenium-based alloy materials that can be used in vapor deposition and atomic layer deposition (ALD) techniques, given exceptional barrier strength. In addition, these ruthenium-based materials and ruthenium-based alloy materials provide better adhesion than previously described, which will have lower electrical resistance, which provides better chemical mechanical polishing (CMP) compatibility with copper. This will provide for lower particle generation and less disturbing chamber maintenance. It would also be advantageous to produce layered materials and films from ruthenium-based materials and / or ruthenium-based alloy materials.

1 is a selective micrograph of (a) Ta and (b) Ti-5at.% Zr alloys hot rolled and annealed,

2 is a TaN deposited in an ion metal plasma (IMP) chamber using a coarse particle Ta (50 μm) target and deposited in a conventional widebody using a fine particle Ti-5 at% Zr (10 μm) target. SEM image of via step coverage geography of TiZrN,

FIG. 3 shows a square dot of data points for which (a) Cu on Si ₃ N ₄ and (b) Stress changes as a function of film thickness for Ru on SiO ₂ failed the tape-pull test. Is a graph

4 is a graph of stress variation with substrate temperature function for (a) Ta and (b) TiZr films of 20 nm thickness,

FIG. 5 shows stress variation with substrate temperature function for 20 nm-Ta / 10 nm-Ru / 1 μm-Cu and 20 nm-TiZr / 10 nm-Ru / 1 μm-Cu film stacks, with square dots in a tape pull test Represents a failed data point, the second graph is a graph with no failed data points,

6 is a view showing the effect of temperature on the stress of the ruthenium film,

FIG. 7 is an SEM cross-sectional micrograph for 20 nm-TaN / Cu and 20 nm-TiZrN / Cu stacks annealed at 750 ° C. for 1 hour.

FIG. 8 shows RBS done after RBS spectra removes protective Si ₃ N ₄ and Cu layers for (a) 27 nm-TaN / Cu and (b) 20 nm-TiZrN / Cu stacks annealed at 700 ° C. for 1 and 5 hours Is a diagram showing a profile,

9 is a SEM cross-sectional view of (a) a TEM microstructure of a 5nm-TiZrN / Cu stack annealed at 650 ° C. for 1 hour and (b) a 25nm-TiZr / Cu stack annealed at 550 ° C. for 1 hour,

10 is a SEM cross-sectional view of a 5 nm-Ru / Cu stack annealed at (a) 700 ° C. and (b) 750 ° C. for 1 hour,

FIG. 11 is an SEM cross-sectional micrograph of (a, b) TiZr / Ru / Cu and (c, d) TiZrN / R / Cu affected at 550 and 650 ° C. for 1 hour, respectively.

12 is a plot of electrical resistance change as a function of film thickness for Ta, Ti, Ru, and Cu,

FIG. 13 shows resistance change as a function of deposition force for TaN and TiZrN films deposited at 400 ° C. FIG.

Summary of the Invention

Alloys for use in vapor deposition or atomic layer deposition are described herein and the alloy includes one or more elements and ruthenium or combinations thereof from Groups IV, V or VI of the Periodic Table of the Elements.

Layered materials are also described herein and include one or more layers comprising ruthenium-based materials or ruthenium-based alloys and one or more layers comprising one or more elements from groups IV, V or VI of the Periodic Table of Elements.

Ruthenium-based materials and ruthenium-based alloy materials that can be used in vapor deposition or atomic layer deposition techniques are provided and will be described herein. In addition, ruthenium-based materials and ruthenium-based alloy materials provide better adhesion than those already described, which provide lower electrical resistance, which provides better chemical mechanical polishing (CMP) compatibility with copper, This will provide for reduced particle generation and for less disturbing chamber maintenance since this is a non-nitridation process. In addition, layered materials are described herein and include one or more layers comprising one or more elements from Groups IV, V or VI of the Periodic Table of Elements and one or more layers comprising ruthenium-based materials or ruthenium-based alloys.

While developing ruthenium-based materials and ruthenium-based alloys that have previously been found to work in the above-described deposition techniques and meet the above-mentioned objectives, the following atoms and atom-molecules: Ta-SiO ₂ , Ti-SiO ₂ , TiZr- SiO ₂ , Ta-Ru, Ti-Ru, TiZr-Ru, Ta-Cu, Ti-Cu, Zr-Cu, and Ru-Cu bonds were found to be good. Using this information, a new set of materials and alloys can be found in Group IV, V or VI elements and Ti-Ru, Zr-Ru, Hf-Ru, TiZr-Ru, V-Ru, Nb-Ru, Ta-Ru, Mo. Alloys with ruthenium such as -Ru, W-Ru, and the like. Based on this action, alloys for use in vapor deposition or atomic layer deposition are described herein and include one or more elements and ruthenium or combinations thereof from Groups IV, V or VI of the Periodic Table of Elements. In addition, this action results in a layered material comprising one or more elements or combinations thereof from the group IV, V or VI of the periodic table of elements and one or more layers comprising ruthenium-based materials or ruthenium-based alloys. The layered material may comprise one or more additional layers, including copper, copper alloys or combinations thereof.

In an embodiment of the invention, each of the one or more layers comprising a ruthenium-based material or ruthenium-based alloy has a thickness of less than about 300 mm 3. In another embodiment, the one or more layers comprising ruthenium-based material or ruthenium-based alloys have a thickness of less than about 200 mm 3. And in another embodiment, the one or more layers comprising ruthenium-based material or ruthenium-based alloy have a thickness of less than about 150 mm 3. The same for one or more layers comprising one or more elements from the Periodic Table group IV, V or VI, the layer or layers may have a thickness of less than about 300 mm 3, a thickness of about 200 mm 3 and / or less than about 150 mm 3 .

Ruthenium concentration can be adjusted to control adhesion and Cu plating performance. TiZr and TiZrN can be compared to ruthenium to show the superiority of ruthenium and ruthenium based alloys in this type of application. For example, TiZr and TiZrN show good barrier strength for Cu diffusion up to 550 ° C. and 650 ° C., respectively, and Ru shows very good barrier strength up to 700 ° C. Most PVD metal films show compressive stress, but the barrier-Cu composite film is stretched, which weakens adhesion. On the other hand, PVD TiZr has low elongation stress and shows no inversion in stress when Cu is deposited. In particular, TiZr-Ru alloys are very important for barrier applications and exhibit particularly good adhesion and direct current Cu plating performance. Apart from the double layer barrier, the TiZr-Ru alloy allows for the preparation of the film in a single deposition process.

The alloys and materials described herein may be used to form sputtering targets, and such targets of the present invention may include any suitable shape and size that depends on the tools and applications used in the PVD process. The sputtering target of the present invention also includes a surface material and a core material, the surface material being connected to the core material. The surface material is in part a portion of the target that is exposed to the energy source at any measurable point in time, and is also the portion of the total target material intended to produce the desired atoms as the surface coating. As used herein, the term "connection" refers to the physical attachment (intermediate adhesion, adhesion material) of two parts consisting of a material and a component, or covalent bonds, and ionic bonds, and van der Waals, for example. By physical and / or chemical attraction between two parts consisting of a material or part comprising a non-bonding force, such as non-bonding force, electrostatic, coulomb, hydrogen bonding, and / or magnetic attraction. The surface material and core material may generally comprise a composition or chemical composition / component of the same element, or the chemical composition and composition of the surface material may be altered or modified differently from the composition and composition of the elements of the core backing material. May be In most embodiments, the surface material and core material comprise the same elemental and chemical composition. However, in embodiments where it may be important to detect when the useful useful life of the target has ended, or in which it may be important to deposit a mixed layer of material, the surface material and core material include a composition or chemical composition of other elements. Can be tailored to

The core material is designed to provide support for the surface material and, if possible, to provide information about when the useful life of additional atoms or targets in the sputtering process is reached. For example, if the core material comprises a material different from the original target surface material and the quality control detects the presence of core material atoms in the space between the target and the wafer, the target may be removed and remounted or discarded. There is a need, because undesired material deposits on current surface / wafer layers may compromise the elemental purity and chemical integrity of the metal coating. The core material is co-owned by Honeywell International, Inc. and as described in PCT Application No. PCT / US02 / 06146 and US Patent Application No. 10/672690, which are incorporated herein by reference in their entirety. It is also part of a sputtering carget that does not contain scale variations or microdimples. In other words, the core material is generally uniform in structure and form.

In general, the sputtering target can be reliably formed as a) a sputtering target; b) sputtered from the target when bombarded by an energy source; And c) any material suitable for forming a final layer or precursor layer on a wafer or surface. Probable materials from which suitable sputtering targets can be made are metals, metal alloys, conductive polymers, conductive composites, conductive units, dielectric materials, hard mask materials and other suitable sputtering materials. As used herein, the term "metal" refers to the d-block and f-block of the periodic table of the elements, along with elements that have properties such as metal, such as silicon and germanium. Means an element in. As used herein, the term "d-block" refers to elements with electrons filling the 3d, 4d, 5d, and 6d orbitals surrounding the nucleus of the element. As used herein, the term "f-block" refers to an element having electrons filling the 4f and 5f orbitals surrounding the nucleus of the element and includes lanthanides and actinides. Possible metals include titanium, silicon, cobalt, copper, nickel, iron, zinc, vanadium, zirconium, aluminum and aluminum based materials, tantalum, niobium, tin, chromium, platinum, palladium, gold, silver, tungsten, molybdenum, cerium, Promethium, thorium or combinations thereof. The term “combination thereof” is used to mean that there may be metal impurities in some sputtering targets, such as copper sputtering targets with chromium and aluminum impurities, or alloys, borides, carbides, fluorides, nitrides, silicides, oxides, etc. It should be understood that it may be used to mean that there may be a planned combination of metals and other materials that make up the sputtering target, such as a target comprising.

A thin film or film made by sputtering of atoms from a target described herein can be any number of or including other metal layers, substrate layers, dielectric layers, hardmask or etch stop layers, photolithography layers, antireflective layers, or the like. It can be formed on a layer of any density. In some preferred embodiments, the dielectric layer may include a dielectric material that has been considered, manufactured, or described by Honeywell International, Inc. Examples of such dielectric materials include: a) FLARE (poly (arylene ether)), for example US Pat. Nos. 5,959,157, 5,986,045, 6,124,421, 6,156,812, 6,172,128, 6,171,687 , 6,214,746, and pending applications 09 / 197,478, 09 / 538,276, 09 / 544,504, 09 / 741,634, 09 / 651,396, 09 / 545,508, 09 / 587,851, 09 / 618,945, 09 / 619,237, 09 / 792,606 Compounds described b) pending application 09 / 545,058; PCT / US01 / 22204, filed October 17, 2001; PCT / US01 / 50182, filed December 31, 2001; 60 / 345,374, filed December 31, 2001; 60 / 347,195, filed January 8, 2002; And adamantane based materials described in 60 / 350,187, filed Jan. 15, 2002 c) US Patent No. 5,115,082 assigned to the applicant; 5,986,045; And 6,143,855; And International Patent Application WO 01/29052, published April 26, 2001, assigned to Applicant; And WO 01/29141, published April 26, 2001; And d) US Pat. Nos. 6,022,812, 6,037,275, 6,042,994, 6,048,804, 6,090,448, 6,126,733, 6,140,254, 6,204,202, 6,208,014, and pending applications 09/06. 046,474, 09 / 046,473, 09 / 111,084, 09 / 360,131, 09 / 378,705, 09 / 234,609, 09 / 379,866, 09 / 141,287, 09 / 379,484, 09 / 392,413, 09 / 549,659, 09 / 488,075, 09 / 566,287, And silica based compounds and nanoporous silica materials, such as the compounds described in 09 / 214,219, and e) Honeywell HOSP® organosiloxanes.

The wafer or substrate may comprise any desired generally solid material. Particularly preferred substrates will include films, glass, ceramics, plastics, metals or coated metals, or composite materials. In some embodiments, the substrate is: a packaging surface, circuit board or package, such as that found on silicon or germanium arsenic die or wafer surfaces, copper, silver, nickel, or gold plated leadframes. Copper surfaces, via-walls or stiffener interfaces ("copper" includes pure copper, copper alloys and oxides), such as those found in interconnect traces, found in polyimide-based flex packages Board interface or polymer based packaging, lead or other metal alloy solder ball surfaces such as those that may be present; Polymers such as glass and polyimide. In a more preferred embodiment, the substrate comprises materials common in the packaging and circuit board industry, such as silicon, copper, glass or polymers. One material layer comprising the substrate layer may comprise the substrate material described above. Another material layer comprising a substrate layer may comprise polymers, units, organic compounds, inorganic compounds, layers of organometallic compounds, continuous layers and nanoporous layers.

The substrate layer may also include multiple voids where nanoporous material is desired instead of continuous material. The voids are typically spherical but may instead or in addition have any suitable shape including tubular, layered, discoid or other shapes. The voids can also have any suitable diameter. At least some of the pores may be connected with adjacent pores to create a structure having significant sizes of interconnected or “opened” cavities. The voids preferably have an average diameter of less than 1 μm, more preferably an average diameter of less than 100 nm, even more preferably an average diameter of less than 10 nm. The voids may be uniformly or irregularly dispersed in the substrate layer. In a preferred embodiment, the voids are uniformly dispersed in the substrate layer.

The provided surface is expected to be any suitable surface, including a wafer, substrate, dielectric material, hardmask layer, other metal, metal alloy or metal composite layer, antireflective layer, or any other suitable layered material, as described herein. do. The coating, layer or film produced on the surface may have any suitable or desired thickness having a range of millimeter thicknesses from one atomic or molecular thickness (less than 1 nanometer).

The ruthenium-based alloys and materials and associated sputtering targets and deposition sources described herein may be incorporated into any process or manufacturing design that alters manufacturing, forming, or vice versa electronic, semiconductor, and communication / data transfer components. Electronic, semiconductor and communication components as expected herein are generally considered to include any layered component that can be used as an electronic, semiconductor or communication based product. Expected components include microchips, circuit boards, chip packaging, separator sheets, circuit boards, printed wiring boards, touch pads, waveguides, dielectric components for optical fibers and optical transmission, and acoustic-wave transmission components. transport), any material that utilizes or introduces a dual damascene process and other components of the circuit board such as capacitors, inductors, and resistors.

Electronic, semiconductor and communication / data delivery products may be "finished" in the sense that they are ready for use by other consumers or in industry. Examples of completed consumer goods are televisions, computers, cell phones, pagers, palm organizers, portable radios, car stereos, or remote controls. Also anticipated embodiments of the present invention are "intermediate" products such as circuit boards, chip packages, and keyboards.

Electronic, semiconductor, and communication / data delivery products may include circular components at any stage of deployment of the final scale-up for life-size in a conceptual model. The prototype may or may not include all of the actual components planned in the finished product, and the prototype may have some components composed of composite materials to negate the initial effects on other components while initially tested.

Target materials used in this study are Honeywell 3N grade Ti-5at.% Zr alloy (hereafter designed as TiZr) (US Patent Publication 2003/0132123), 3N5 grade Ta, and 3N5 grade Ru. TiZr and Ta targets are formed from a metal sheet that is hot rolled. Ti addition of 5 atomic% Zr produces microstructures with an average particle size of less than 10 μm. The particle size of the hot rolled Ta is in the range of 30-50 μm. 1 shows an optical micrograph of Ta and TiZr alloys. Ti and Zr are in the same group in the periodic table and produce solid solutions with full miscibility in the entire composition range. Ru targets are manufactured through powder metallurgy, which is accompanied by a final vacuum high temperature treatment. The average particle size of the finished target is 85 μm or less.

Nitride films are made by reactive physical vapor deposition (PVD) in an Applied Materials P5500 Endura® system that allows for in-line deposition of metals, nitrides, and copper. The film is made on a 200 nm wafer. Specific deposition conditions are solved using data. Some Ru films are electrochemically plated using Cu to demonstrate the galvanizing performance and to evaluate the complete bond strength. In specimens used for Cu diffusion studies, the final capping was applied using PVD TaN or chemical vapor deposition (CVD) Si ₃ N ₄ to protect the copper film from oxidation during heat treatment. .

Rutherford backscattering spectroscopy (RBS) and scanning electron microscopy (SEM) are used to determine the extent of Cu diffusion. Transmission electron microscopy (TEM) is performed to examine the film microstructure. Flexus strength gauge is used to measure film stress. Bond strength is evaluated by the following ASTM Standard Tape Test Method [8] and evaluated by SEM cross-sectional examination. The SEM cross-sectional investigation method was found to be the most rigorous and accurate method for evaluating bond strength and determining the extent of Cu diffusion. If the wafer is cracked in SEM irradiation, de-bonding occurs and the interface is weak. This is evident in the SEM even if the tape test fails to identify weakly bound interfaces. Film sheet resistance (R _S ) is measured using a CDE ResMap 4-point electron-probe. The volumetric electrical resistance ρ is given by detection in the formula ρ = R _S t, where “t” is the film thickness. Film thickness is achieved from film weight and specific gravity, and deposition rates well detected by SEM cross-sectional methods.

Results and review

Sputtering target

The Vickers hardness value of the hot rolled Ti-5at% Zr alloy is about 210 ksi (1.45 GPa), which is almost three times the value of Ta (Hv = 85 ksi or 0.59 GPa). For both metals there is no significant hardness change after thermal anneal at 200 ° C. for 24 hours. The 0.2% yield strength ranges from 68 and 33 ksi for TiZr and Ta, respectively. The improved strength of the TiZr alloy is due to the solution hardening achieved by the relevant refinement of the particle size and the addition of large Zr atoms.

The thermal stability and mechanical strength of the targets are particularly important for applications requiring high power operation, as long as the self-ionization-plasma (SIP) system [13] is in long throw. In addition, the excellent mechanical strength, TiZr is low in cost, light in weight, easy to handle, easy to manufacture uniform structures, is available in high purity, and low in the supply chain. Hexagonal close packed (h.c.p) TiZr produces a uniform crystal structure and therefore no change in deposition rate associated with non-uniform crystal structure is observed. Forged Ta, on the other hand, is often known to produce highly textured or banded targets and unacceptable film uniformity [14]. This is mainly done by b.c.c. This is because it is a slip system. Ta tends to leave a persistent remnant of as-cast crystals that cause banded or tissue microstructures after annealing.

Deposition performance

Refinement of the crystal size is particularly important because the target crystal size affects mechanical strength, deposition yield and step coverage. 2 compares the TaN step coverage for a 0.4 μm bias with 4.3 aspect ratio (AR) and the TiZrN step coverage for a 0.16 μm bias with an AR of 5. FIG. TaN is relatively deposited with nitrogen in the ion metal plasma (IMP) using 4 kW power (25 sccm Ar, 28 sccm N ₂ ) at 14 mT. TiZrN films are relatively deposited in conventional widebody chambers using 6.5 kW power (55 sccm Ar, 75 sccm N ₂ ) at 4.3 mT. It is evident that TiZr targets of smaller crystal size deliver even more pronounced better step coverage compared to sidewall coverage with respect to the total thickness of the deposited film, even with conventional deposition methods and smaller via structures. Finer crystal targets show longer target life due to improved collimation for the sputtered atomic beam [15, 16]. The physical principle is based on the fact that atoms sputtered from grooved crystal boundaries are more focused than atoms sputtered from flat crystal surfaces, and some of the aimed beams increase by subdividing the crystal size or introducing more crystal boundary grooves. Since the focused atomic beam has less off-normal beam, deposition yield and step coverage are improved. At the same time, the reduced sidewall deposition rate extends shield life and makes chamber maintenance less frequent.

Attach

Although both Ta and TaN show very good barrier strength to Cu diffusion, the TaN / Ta double layer approach is adopted for barrier applications because Ta adhesion to dielectrics (ie Si, SiO ₂ ) is not good. . This is mostly due to the high compressive stress of the Ta film as described in the next paragraph. In the double layer manner, the metal Ta can be added as an adhesive layer because Cu does not adhere well to the nitride.

Extensive features of adhesion strength are implemented in various film stacks to understand the nature of the adhesion. Only significant results are summarized in Table 1. The main reason for this action is to identify a barrier system that exhibits good adhesion strength, good barrier strength, ie, direct current Cu electrochemical plating performance using Ru. These results indicate that only Ru does not provide adequate adhesion strength to the dielectric, Cu does not adhere well to nitrides such as TaN and TiZrN, and that adhesion to Ta to the dielectric is not very good. . Both Ta and TiZr do not allow direct current Cu electrochemical plating. Thus, a PVD Cu-seed layer is deposited before Cu electroplating. For Ru specimens, PVD and ECP methods are used for Cu deposition. Substantially identical effects on stress and adhesion are formed in both methods. Of all the matrices tested, only TiZr / Ru, TiZrN / Ru, and TaN / Ru bilayers meet the adhesion and plating requirements and are identified as acceptable candidates.

Accurate analysis shows that the adhesion strength is almost determined by the film stress. This analysis is reviewed in the next paragraph.

The> <sign indicates a failed interface.

Stress

Stress analysis is carried out using the well-known Stoney's equation for biaxial films. Where σ is the average film stress [Pa] in the SI unit, E is the modulus of elasticity of the substrate [Pa], v is the Poisson's ratio, t is the film thickness [m], and h is the substrate thickness [m] And R ₁ and R ₂ are the radius of curvature [m] before and after film deposition, respectively. In the stress calculation, E / (1- v ) = 1.8 × 10 ¹¹ Pa is used for (100) Si.

3 compares stress trends for Cu and Ru as a function of film thickness. A Cu film is deposited on a Si ₃ N ₄ coated Si-wafer at 2 kW power state ambient temperature because Cu diffuses through SiO ₂ and Si. Although copper films exhibit tensile stress for compressive Ru films, the stress tendency changes from compression to tensile direction for both Cu and Ru and increases film thickness. Careful examination of the curve indicates that a tape-pull test attachment failure occurs when the stress- tendency changes from compressive to tensile direction (buckling). The combination between 'buckling' and 'adhesion failure' is consistently observed in many experiments [10]. The reversal in stress tendency is not evident in Cu, and although Cu is initially deposited as a compressive film, it is apparent that it is pulled out due to rapid dynamic annealing during deposition. Copper is known to anneal even at room temperature [17]. These points are described in more detail below.

In general, PVD films are substantially compressed due to shot-peening, which compresses the film by hammering with particles. Typical process Ar + ion energy is 400 eV, for example. When half of the Ar + ion energy is transferred to the sputtered atoms, the atoms fly out at speeds faster than 10 km / s. When these high speed atoms impact the substrate, serious damage to the film in the form of dislocations is introduced, causing compression. PVD films thus maintain a high density of dislocations. This is confirmed by TEM. The stored energy of the potential becomes the driving force for recovery and recrystallization. This effect is more pronounced for metals with low melting points such as pure Al and Cu. In alloyed Al, this recovery is substantially delayed due to solute pinning. Although not shown due to space constraints, careful examination of the stress data indicates that Al and Cu deposit as compressed films but are tensioned due to power recovery during deposition. This can be confirmed by depositing the film at very low temperatures. The degree of thermally driven recovery occurs in Cu, which depends on the deposition state, especially when the substrate is subjected to a high temperature plasma atmosphere.

4 compares the stress variation with substrate temperature function for Ta and TiZr films deposited at 4 kW power. All films are 20 nm thick. Ta films exhibit extremely high compressive stresses over 2000 MPa over most temperature ranges. Even at high stresses, there is no failure to attach, because the stress does not change gradually (no buckling effect). However, adhesion stability is not maintained for very high compressive Ta films when tensile Cu films are deposited as described below. TiZr films exhibit somewhat neutral stresses between -150 and +400 MPa at all temperatures, and no deposition failure is expected after Cu deposition.

Since the final performance must be demonstrated for the film stack expected in the actual device, the triple film stack is coated with SiO ₂ as 20 nm-Ta / 10 nm-Ru / 1 μm-Cu and 20 nm-TiZr / 10 nm-Ru / 1 μm-Cu. Is prepared on a Si wafer. This will produce several nm thick films and is typically a bias / trench liner thickness that depends on the PVD method and feature size used. Barrier metal films (Ta, TiZr, Ru) are deposited at 100 ° C. in a 2 kW power state and copper films are deposited at ambient temperature in a 2 kW power state. FIG. 5 shows stress variation with substrate temperature function for Ta / Ru / Cu and TiZr / Ru / Cu film stacks. The final stress values represent a range of 500 MPa for all types of film stacks, suggesting the thickest Cu films whose final stresses have been determined as can be seen by comparison with FIGS. 3 and 5. As expected, the Ta-based barrier film fails the tape pull test as a result of conduction of the stressed state from high compressive forces to tension after Cu deposition. In contrast, the neutral TiZr based barrier stack maintains very good adhesion even after Cu deposition. It is clear that the stress is one of the factors that govern the attachment.

As expected, the high melting point nitride film exhibits a compressive stress much higher than 3000 MPa compressive force for both TaN and TiZrN films deposited below 100 ° C. In fact neutral film stress is achieved for TiZrN films deposited between 200 ° C. and 300 ° C., but TaN film stresses retain compressive forces even at elevated deposition temperatures. Even with high compressive stress, the nitride film shows good adhesion only after Cu deposition. In general, non-metal to non-metal bonds are found to be good, for example, in SiO ₂ -TaN and SiO ₂ -TiZrN. The final composite film stress has a tensile force of about 450 MPa at 20 nm-TaN / 10 nm-Ru / 1 μm-Cu, and a tensile force of 300 MPa or less at 20 nm-TiZrN / 10 nm-Ru / 1 μm-Cu. For Cu electroplating and diffusion barrier strength evaluation, nitrides and Ru films are deposited at 200 ° C. 6 shows the effect of temperature on stress for ruthenium films on SiO ₂ . Ruthenium film stress changes from compressive to tensile as the deposition temperature increases.

Cu plating

Cu can be directly electroplated even on 5 nm thin Ru films without any difficulty. The adhesion test shows no delamination problems in either TiZr / Ru / ECP-Cu or TiZrN / Ru / ECP-Cu, and the TiZr / Ru and TiZrN / Ru barriers are PVD and ECP Cu as long as they are stress related. It is compatible in all.

In general, metal to nonmetal bonds (ie, Ta—SiO ₂ ) are weaker than metal to metal bonds (ie, Ta—Cu). Cu plating inability to Ta or Ti is associated with the oxide layer and prevents non-high electrical resistance adhesion. Cu may be plated on Ta and Ti but does not adhere well. Cu and Ru form oxides, but as compared to Table 2, they become less stable due to their relatively low oxygen affinity compared to Ta and Ti. Ruthenium has a low binding energy for oxygen, has a high standard Gibbs energy for oxide formation, and has a similar negative charge. Thin copper oxides are known to readily dissolve in contact with sulfuric acid. It is believed that Ru is a more precious metal than copper and a less stable ruthenium oxide readily oxidizes and dissolves the Cu plating.

Barrier  burglar

In evaluating barrier strength against Cu diffusion, TaN and TiZrN films were deposited at 400 ° C./6.5 kW / 5 mT at 35 sccm Ar and 75 sccm N ₂ gas flow rates. RBS analysis shows that the metal-to-stoichiometric Ta ₀ N _{0 .6-0.4 .4-0.6} and (TiZr) _0.47-0.60 N _{0 .53-0.40} range of nitrogen. The Ti / Zr ratio in the film is almost the same as that of the target, so sputtering does not appear to change the target or film composition. Ta and TiZr metals are deposited at 400 ° C./2 kW / 2.3 mT Ar pressure. Si ₃ N ₄ capping is applied before the film is annealed to protect the film from oxidation. A Ru film stack is prepared by depositing 5 nm Ru accompanied by Cu below 200 nm using final TaN capping. Ruthenium is deposited at 100 ° C. and Cu is deposited at ambient temperature.

The barrier strength of the metal is lower than that of counterpart nitride. TaN and TiZrN show very good barrier strengths up to 700 ° C., while Ta and TiZr of metals show stability up to 550 ° C. As a metal, Ru exhibits exceptional barrier strengths up to 700 ° C. Specific examples are described below.

The SEM cross section shows substantial Cu diffusion through TaN and TiZrN after annealing at 750 ° C. for 1 hour, as shown in FIG. 7. However, at 700 ° C., there are no signs of Cu diffusion even after 5 hours of annealing. FIG. 8 compares RBS profiles for samples annealed for 1 to 5 hours for both TaN and TiZrN. In this case, the Cu layer is removed before the RBS analysis so that the Cu surface is not affected by the analysis. The Si ₃ N ₄ and Cu layers are removed by chemical polishing with condensed HF and diluted HNO ₃ acid respectively. There is no discernible difference in the RBS spectra between the 1 and 5 hour annealed samples and no Cu traces in the RBS spectra. FIG. 9 shows a cross-sectional view of a TEM microstructure of TiZrN annealed at 650 ° C. for 1 hour and an SEM microstructure of TiZr annealed at 550 ° C. for 1 hour. In both cases, the substrate is cleaned and there is no indication of any copper diffusion.

10 shows the barrier strength of Ru affected at 700 ° C. for 1 hour. The SEM cross section shows no signs of copper diffusion in the 5 nm thin Ru barrier. For samples annealed at 750 ° C. for 1 hour, sporadic patches of diffused areas are observed. However, significant deterioration of the Ru / Cu interface as seen in the SEM cross section occurs, particularly for samples annealed at 750 ° C. There is no Ru-Cu phase formed at this temperature, but the Ru-Cu interaction at elevated temperatures seems to cause the formation of intermetallic compounds that weaken the Ru-Cu interface bonds.

FIG. 11 shows SEM cross-sectional micrographs for TiZr / Ru / Cu or TiZrN / Ru / Cu annealed at 550 ° C. and 650 ° C. for 1 hour. TiZr / Ru shows very good barrier strength up to 550 ° C. and shows no copper diffusion and no delamination phenomena, but shows obvious barrier degradation at 650 ° C. Since Ru appears to prevent copper diffusion up to 700 ° C, the degradation at 650 ° C appears to be related to the interaction of the self barrier with the substrate, not by copper diffusion. In deterioration, no delaminate appears at the copper / barrier.substrate interface. TiZrN / Ru shows good adhesion and barrier strength at all of the temperatures as expected.

Of all the barriers investigated, especially ruthenium as the metal is known as the best diffusion barrier. However, weakening the adhesion strength to the dielectric weakens the contender. Ta also exhibits weak adhesion strength to the dielectric. In short, the observed barrier strengths were Ta (550 ° C), TiZr (550 ° C), TiZr / Ru (550 ° C), TaN (700 ° C), TiZrN (700 ° C), TaN / Ru (700 ° C), TiZrN / Ru (700 ° C.), and Ru (700 ° C.) in order. In terms of adhesion and electroplating, TiZr / Ru, TiZrN / Ru, and TaN / Ru are identified as three top contenders in barrier applications.

Electrical resistance

12 shows the measured electrical resistance as a function of film thickness for Ta, Ti, Ru, and Cu. The resistance values of the thick films were 15 μm-cm for Ta, 64 (Ti, 100 ° C), 13 (Ru, 100 ° C), 10 (Ru, 400 ° C), and 1.9 (Cu, RT) deposited at 100 ° C. Has a range. This is rather high compared to the bulk resistance values of Table 3, somewhat very well annealed metal. Excessive resistance is typically due to high scattering and enhanced scattering at the fine columnar crystal boundaries in PVD films. The resistance of Ru deposited at 400 ° C. is lower than the resistance of Ru at 100 ° C. as expected.

The electrical resistance ρ substantially increases with decreasing film thickness due to enhanced electron scattering at the surface and interface. The average free path length λ is calculated by λ = τ V _F , where τ is the average free time between collisions and V _F is the Fermi velocity. The film and bulk resistance are ρ _film ∝ ρ _bulk (1+ λ / t ), where t is the film thickness. Detailed calculation methods can be found in references [18, 19] and in other solid state physics books. Overall, the experimentally measured film resistance values are considerably higher than the theoretically predicted values due to the high density bonds in the PVD film.

Among the data shown in FIG. 12, Ta exhibits a rare bimodal resistance tendency, greater than 200 μm-cm for films thinner than 40 nm, and exhibits almost the same resistance value as that of Ti. Thus, Ta does not appear to have any advantage in resistance over Ti for films expected in microelectronic interconnect liner applications. It can be seen that Ta nucleates as bcc α-Ta (low resistance) on TaN and tetragonal β-Ta (high resistance) on SiO ₂ [20]. The findings suggest that Ta initially becomes α-form as the Ta-film thickens to β-form on SiO ₂ . On the other hand, Ru shows a substantially lower resistance of less than 26 μm-cm for 10 nm films. overtly. Low electrical resistance is an additional advantage of TiZr / Ru for barrier applications.

The resistance value of the nitride film is substantially higher than that of the corresponding metal. FIG. 13 shows the resistance value as a function of deposition force for films thicker than 200 nm. TaN generally has a high resistance value of 2280 μm-cm at 2 kW, which quickly decreases to 254 μm-cm as the power increases to 8.6 kW. On the other hand, the resistance of TiZrN film is almost unchanged with respect to power and has a very low value at all power levels, varying from 106 to 69 μm-cm and increasing power from 2 to 8.6 kW, respectively. SEM and TEM irradiation rarely indicates that high TaN resistance is associated with low specific gravity and high amorphous fraction, which resistance increases with decreasing deposition force. The density increases from 3.8 to 13.9 g / cm 3 when the deposition force increases from 2 to 8.6 kW, followed by a decrease in film resistance.

Thus, in certain embodiments and applications of the novel ruthenium materials and alloys, the films made from them and their use in atomic layer deposition or vapor deposition are described. However, it will be apparent to those skilled in the art that many modifications other than those described above are possible without departing from the spirit of the invention. Thus, the content of the invention, including the claims, is not limited by other than the spirit of the specification described herein. In addition, in interpreting the specification and claims, all terms should be interpreted in the broadest possible manner consistent with the possible context. In particular, the term "comprising" and "comprising" should be interpreted to refer to an element, part, or step in a non-exclusive manner, whereby the element, part, or step referred to is another element, part or element not explicitly mentioned. It means that can be combined or used or present with them.

Reference

Note: Some references below are incorporated directly in this application specification. References not directly cited in the present specification are generally considered to contribute to the main purpose of the present application or to provide general knowledge.

Oliver Chyan et al., Abs. 595, 20th Meeting, The Electrochemical Society, Inc., (2003).

Lane, et al., USP 6,787,912 (2004).

Fred Fishburn, USP 6,787,833 (2004).

4. Eugene P. Marsh, USP 6,787,449 (2004).

5. Dong-Soo Yoon and Jae Sung Rho, IEEE Electron Device Letters, 23 (4) (2003) p. 176.

6. A. H. Fisher, A. von Glaswo, S. Penka, and F. Unger, Proc. IITC 2003, IEEE Electron Devices Society (2003) 253.

7.D. Edelstein, C. Uzoh, C. Cabral, Jr., P. DeHaven, P. Buchwalter, A. Simon, E. Cooney, S. Malhotra, D. Klaus, H. Rathore, B. Agarwala, and D. Nguyen, Proc. IITC 2001, IEEE Electron Devices Society (2001) 9.

8. Barry L. Chin, Gongda Yao, Peijun, Jianming Fu, and Liang Chen, Semiconductor International, 24 (2001) 107.

9. Ishita Goswami and Ravi Laxmann, Semiconductor International, 27 (5) (2004) p. 49.

10.Eal Lee, Nicole Truong, Nancy lwamoto, Wener Hort, Mike Pinter, and Janine K.ardokiis, submitted to IITC 2005.

Paul Besser, Amit Marathe, Larry Zhao, Matthew Herrick, Cristiano Capasso, Hisao Kawasaki. Technical Digest-International Electron Devices Meeting (2000), pp. 119-122.

12.K. Y. Lim, Y. S. Lee, Y. D. Chung, 1. W. Lyo, C. N. Whang, J. Y. Won, H. J. Kang. Appl. Phys. A 70 (2000) p. 431.

13.Cross-cut tape test by ASTM D3359-95, Annual Book of ASTM Standards, Vol. 06.01.

14. Christopher A. Michaluk, J. Electronic Materials, 31 (1) (2002) 2-9.

15. Eal Lee, Cara Hutchison, Anil Bhanap, Nicole Truong, Robert Prater, Mike Pinter, and Wuweii Yi, Advances Electronics Manufacturing Technology, www.Vertilog.com, V-EMT 1:16 (2004).

16.Eal Lee, Nicole Truong, Bob Prater, Wuwen Yi, and Janine Kardokus, submitted to J. Vac. Sci. Technol. B

17. Qing-Tang Jiang and Michael E. Thomas, J. Vac. Sci. Technol. B 19 (3) (2001) p. 762.

18. Frank J. Blatt. "Physics of Electronic Conduction in Solids." McGraw-Hill. New York 1968

19. S. 0. Kasap, "Principles of Electronic Materials and Devices." McGraw Hill. New York, 2002.

20. Martin Traving, Guenther Schindler, Gernot Steinlesberger, Werer Steinhoegi, and Manfred Engelhardt, Semiconductor International 26 (8) (2003) p. 73.

Claims (26)

As an alloy for use in vapor deposition or atomic layer deposition, Comprising at least one element and ruthenium or combinations thereof from groups IV, V or VI of the periodic table of elements alloy. The method of claim 1, The at least one element comprises Ta, Ti, Zr, Hf, V, Nb, Mo, W or combinations thereof alloy The method of claim 1, Further comprising silicon, oxygen, nitrogen or a combination thereof alloy. A sputtering target comprising said alloy of claim 1. The method of claim 1, The vapor deposition includes physical vapor deposition or chemical vapor deposition alloy. Film prepared using the alloy of claim 1. The method of claim 6, The film is a copper diffusion barrier film film The method of claim 7, wherein The film is used for seedless copper electroplating film. The method of claim 6, The film has improved adhesion compared to films made from non-ruthenium based alloys film. A part formed by the sputtering target of claim 4. A component for introducing the film of claim 6. As a layered material, One or more layers comprising a ruthenium-based material or ruthenium-based alloy; And One or more layers comprising one or more elements or combinations thereof from Groups IV, V or VI of the Periodic Table of Elements Layered materials. The method of claim 12, The at least one element comprises Ta, Ti, Zr, Hf, V, Nb, Mo, W or combinations thereof Layered materials. The method of claim 12, Wherein said at least one layer comprising at least one element or combination thereof from Groups IV, V or VI of the Periodic Table of Elements further comprises silicon, oxygen, nitrogen or a combination thereof Layered materials. The method of claim 12, The material is a copper diffusion barrier film Layered materials. The method of claim 15, The material is used for sidless copper electroplating Layered materials. The method of claim 16, The material has improved adhesion over layered materials made from non-ruthenium based materials Layered materials. The method of claim 12, Each of the one or more layers comprising a ruthenium-based material or ruthenium-based alloy has a thickness of less than about 300 microns Layered materials. The method of claim 18, Each of the one or more layers comprising a ruthenium-based material or ruthenium-based alloy has a thickness of less than about 200 microns Layered materials. The method of claim 19, Each of the one or more layers comprising a ruthenium-based material or ruthenium-based alloy has a thickness of less than about 150 microns Layered materials. The method of claim 12, Each of the one or more layers comprising one or more elements from groups IV, V or VI of the Periodic Table of Elements having a thickness of less than about 300 GPa Layered materials. The method of claim 21, Each of the one or more layers comprising one or more elements from groups IV, V or VI of the Periodic Table of Elements having a thickness of less than about 200 μs Layered materials. The method of claim 22, Each of the one or more layers comprising one or more elements from groups IV, V or VI of the Periodic Table of Elements having a thickness of less than about 150 GPa Layered materials. The method of claim 12, Having one or more additional material layers Layered materials. The method of claim 24, The at least one additional material layer comprises copper, a copper alloy or a combination thereof Layered materials. A component for introducing the layered material of claim 12.

Images