Abstract:
Compositions of matter, compounds, articles of manufacture and processes to reduce or substantially eliminate EM and/or stress migration, and/or TDDB in copper interconnects in microelectronic devices and circuits, especially a metal liner around copper interconnects comprise an ultra thin layer or layers of Mn alloys containing at least one of W and/or Co on the metal liner. This novel alloy provides EM and/or stress migration resistance, and/or TDDB resistance in these copper interconnects, comparable to thicker layers of other alloys found in substantially larger circuits and allows the miniaturization of the circuit without having to use thicker EM and/or TDDB resistant alloys previously used thereby enhancing the miniaturization, i.e., these novel alloy layers can be miniaturized along with the circuit and provide substantially the same EM and/or TDDB resistance as thicker layers of different alloy materials previously used that lose some of their EM and/or TDDB resistance when used as thinner layers.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of the invention in one aspect comprises interconnection structures (interconnects) in microelectronic circuits including high speed microprocessors, application specific integrated circuits, memory storage devices, and related electronic structures. More particularly this invention relates to ultra thin liner layers for protecting interconnect-metallization in nano Back End Of Line (BEOL) Cu interconnect structures in such microelectronic circuits as well as processes, compositions, and tools for forming such interconnects. The present invention also relates to semiconductor interconnect compositions having enhanced electromigration (EM), stress migration, and time-dependent-dielectric-breakdown (TDDB) reliability, as well as processes and tools for applying these compositions to such interconnects as ultra thin layers 
       BACKGROUND OF THE INVENTION 
       [0002]    The so-called “silicon revolution” brought about the development of faster and larger computers beginning in the early 1960s with predictions of rapid growth because of the increasing numbers of transistors packed into integrated circuits with estimates they would double every two years. Since 1975, however, they doubled about every 18 months. 
         [0003]    An active period of innovation in the 1970s followed in the areas of circuit design, chip architecture, design aids, processes, tools, testing, manufacturing architecture, and manufacturing discipline. The combination of these disciplines brought about the VLSI era and the ability to mass-produce chips with 100,000 transistors per chip at the end of the 1980s, succeeding the large scale Integration (“LSI”) era of the 1970s with only 1,000 transistors per chip. (Carre, H. et al. “Semiconductor Manufacturing Technology at IBM”,  IBM J. RES. DEVELOP.,  VOL. 26, no. 5, September 1982). Mescia et al. also describe the industrial scale manufacture of these VLSI devices. (Mescia, N. C. et al. “Plant Automation in a Structured Distributed System Environment,”  IBM J. RES. DEVELOP.,  VOL. 26, no. 4, July 1982). These VLSI devices have now been advanced to the next level of miniaturization referred to as Ultra-Large Scale Integrated (ULSI) microelectronic circuits. 
         [0004]    The release of IBM&#39;s Power6™ chip in 2007, noted this ULSI “miniaturization has allowed chipmakers to make chips faster by cramming more transistors on a single slice of silicon, to the point where high-end processors have hundreds of millions of transistors. “(http://www.nytimes.com/reuters/technology/tech-ibm-ower.html?pagewanted=print (Feb. 7, 2006)). 
         [0005]    Technology scaling of semiconductor devices to 90 nm and below has provided many benefits in the field of microelectronics, but has introduced new considerations as well. While smaller chip geometries result in higher levels of on-chip integration and performance interconnect structures the nano structures employed introduce new considerations that the industry has to address such as protecting nano structure interconnects in BEOL structures such as ULSI microelectronic circuits. 
         [0006]    Traditional semiconductor devices, consisting of aluminum and aluminum alloys have been used as interconnect metallurgies for providing electrical connections to and from devices in BEOL layers. While aluminum-based metallurgies have been the material of choice for use as metal interconnects in the past, aluminum no longer satisfies the requirements for increased circuit density and speed in semiconductor devices as the scale of devices decreases. More advanced manufacturing therefor employs copper as a replacement for aluminum, because of its lower susceptibility to electromigration (EM) failure and its lower resistivity as compared to aluminum. 
         [0007]    Since the 1960&#39;s electromigration (EM) has been identified as significant metal failure mechanisms in semiconductor interconnect structures, especially for very large scale integrated (VLSI) circuits and manufacturing as well as ultra large scale integrated (ULSI) circuits and manufacturing. The problem not only needs to be overcome during the process development period in order to qualify the process, but it also persists through the lifetime of the chip, which the industry refers to as time-dependent-dielectric-breakdowns (TDDB&#39;s). EM, results from voids created inside the metal conductors of an interconnect structure due to metal ion movement caused by the high density of current flow. 
         [0008]    Although the fast diffusion path in metal interconnects varies depending on the overall integration scheme and materials used for chip fabrication, it has been observed that metal atoms, such as Cu atoms, transported along the metal/post planarized dielectric cap interface play an important role on the EM lifetime projection. The EM initial voids first nucleate at the metal/dielectric cap interface and then grow in the direction to the bottom of the metal interconnect, which eventually results in a circuit dead opening. 
         [0009]    Circuit interconnects comprising vias known in the art contain a copper core surrounded by a liner to protect against EM, stress migration and TBBD breakdown caused by minimization of circuits and concomitant decreases in wire dimension that brings about increases in current density. 
         [0010]    Liner layers and capping layers are also used in copper interconnect technology to prevent corrosion of the copper wires by sealing the top surfaces of the wires between wiring levels. Again, as wire dimensions decrease, current density increases and the “weakest” sites for resisting EM failure are the liner layer and the capping layer copper interface. Metal liner layers and capping layers improve EM performance but at the cost of increased copper corrosion. 
       Related Art 
       [0011]    Ishizaka et al U.S. Pat. No. 8,242,019, Iwasaki U.S. Pat. No. 7,977,239, Abe U.S. Pat. No. 7,211,505, Yakobson et al. U.S. Pat. No. 7,393,781, Bao et al. U.S. Pat. No. 8,129,269, Bonilla et al. U.S. Pat. No. 7,749,892, Dubin et al. U.S. Pat. No. 7,008,872, Goodner et al., U.S. Pat. No. 7,344,972, Lin et al. U.S. Pat. No. 8,202,783, Yang et al., U.S. patent application Ser. No. 2011/0049716 all show various state of the art liner structures. 
       SUMMARY OF THE INVENTION 
       [0012]    The present invention comprises structures, articles of manufacture and processes that address these needs not only to provide advantages over the related art, but also to obviate substantially one or more of the foregoing and other limitations and disadvantages of the related art. The present invention provides compositions of matter, compounds, articles of manufacture and processes to reduce or substantially eliminate EM and/or stress migration, and/or TDDB in copper interconnects in microelectronic devices and circuits, especially the metal liners described above, by means of an ultra thin layer or layers of Mn alloys containing W and/or Co. This novel alloy composition provides EM and/or stress migration, and/or TDDB resistance in copper interconnects in microcircuits comparable to thicker layers of other alloys found in substantially larger circuits and allows the miniaturization of the circuit without having to use thicker EM and/or TDDB resistant alloys previously used thereby enhancing the degree of miniaturization. Stated otherwise, these novel alloy layers can be miniaturized along with the circuit and provide substantially the same EM and/or TDDB resistance as thicker layers of different alloy materials previously used. In prior art, CoWP metal alloy Cap, the stress migration/EM performance are strongly dependent on the CoWP thickness (J. Gambino et al. , IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY, VOL. 6, NO. 2, JUNE 2006, and Interconnect Technology Conference, 2005. Proceedings of the IEEE 2005 International, pp. 111-113_) 
         [0013]    Not only do the written description, drawings (Figures) claims, and abstract of the disclosure set forth various features, objectives, and advantages of the invention and how they may be realized and obtained, but these features, objectives, and advantages will also become apparent by practicing the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The accompanying drawings are not necessarily drawn to scale but nonetheless set out the invention, and are included to illustrate various embodiments of the invention, and together with this specification also serve to explain the principles of the invention. These drawings comprise various Figures that illustrate, inter alia, structures and processes for practicing the invention. 
           [0015]      FIGS. 1A through 1E  are side elevations in cross-section illustrating fabrication of damascene and dual-damascene interconnect wires according to embodiments of the present invention. 
           [0016]      FIGS. 2A through 2C  comprise side elevations in cross-section illustrating fabrication of in-situ of metal alloy liners and in-situ formation of metal cap/dielectric cap on the wires of  FIG. 1  according to a first embodiment of the invention. 
           [0017]      FIGS. 3A through 3D  comprise side elevations in cross-section illustrating fabrication of in-situ of metal alloy liners and in-situ formation of metal cap/dielectric cap on the wires of  FIG. 1  according to a second embodiment of the invention. 
           [0018]      FIGS. 4A through 4D  comprise side elevations in cross-section illustrating variations to the first and second embodiments of the present invention. 
           [0019]      FIGS. 5A through 5D  comprise side elevations in cross-section illustrating fabrication in-situ of metal alloy liners and in-situ formation of metal cap/dielectric cap on the wires of  FIG. 1  according to a third embodiment of the invention. 
           [0020]      FIGS. 5A through 5C  and  5 E- 5 F comprise side elevations in cross-section illustrating fabrication in-situ of metal alloy liners and in-situ formation of metal cap/dielectric cap on the wires of  FIG. 1  according to a fourth embodiment of the invention. 
           [0021]      FIGS. 6A and 6B  comprise side elevations in cross-section illustrating variations to the third and fourth embodiments of the present invention. 
           [0022]      FIGS. 7A through 7D  illustrate a first set of tools for forming in-situ interconnects and the formation of metal alloy liners according to the first and third embodiments of the present invention; and 
           [0023]      FIGS. 8A through 8C  illustrate a second set of tools for forming in-situ interconnects and the formation of metal alloy liners according to the second and fourth embodiments of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    To achieve the foregoing and other advantages, and in accordance with the purpose of this invention as embodied and broadly described herein, the following detailed description comprises disclosed examples of the invention that can be embodied in various forms. 
         [0025]    The specific processes, compounds, compositions, and structural details set out herein not only comprise a basis for the claims and a basis for teaching one skilled in the art how to employ the present invention in any novel and useful way, but also provide a description of how to make and use this invention. This written description, claims, abstract of the disclosure, and drawings set forth various features, objectives, and advantages of the invention and how they may be realized and obtained. These features, objectives, and advantages will also become apparent by practicing the invention. 
         [0026]    The invention comprises, among other things: 
         [0027]    (1) various processes (CVD/ALD selective and non-selective) and Cu nano interconnect structures formation with an ultra thin nano layer liner (from about 0.3 to about 1 nm thick) selective liner layer of alloys of Co/Mn, Co/Mn/W, W/Mn, W/Mn/Co and various alloy combination of Co/Mn/W layers as ultra thin alloy liners to improve nano device&#39;s EM and TDDB. These could be deposited sequentially, or co-deposited by concurrent flow of multiple precursors, so as to produce a nano-layer Mn metal alloy liner film. The amount of each element in the alloy, ranges from about 0.1 to about 20 parts by weight of Mn; about 0 to about 100 parts by weight of W; and about 0 to about 100 parts by weight of Co to form Co/Mn, Co/Mn/W, W/Mn, and W/Mn/Co alloys; 
         [0028]    (2) various processes and Cu nano interconnect structure formation with nano layer liners (about 0.3 to about 1 nm thick) selective Co/Mn, Co/Mn/W, W/Mn, W/Mn/Co and various combinations of Co/Mn/W layers as ultra thin metal alloy liners to improve nano device&#39;s EM resistance and TDDB resistance; 
         [0029]    (3) UV or/and Low rf/down stream plasma or thermal cure treatment in reactive hydrogen or other reducing environments (H2, NH3,CO and art-known equivalents) or inert gas (N, Ar, He, .Ne, Kr, Xe and art-known equivalents) ambient to enhance the reaction/intermixing between each layer and between Cu/Metal alloy interfaces; 
         [0030]    (4) multilayer metal and alloy liners in Cu interconnects; 
         [0031]    (5) the above processes, to form non-corrosive coatings for thick/large Cu wiring levels, such as metal pads used in C4 flip-chip and wire bonds, or high-Q inductors, laser-blown fuses, and the like; (the thickness of the substrate is from about 100 mu to about 10000 mu) 
         [0032]    (6) the above processes for manufacturing Cu-based MEMS elements, such as switches and resonators, where a self-aligned corrosion-resistant coating is required; 
         [0033]    (7) integrated in-situ apparatus configuration/processes as illustrated In  FIGS. 7A-7D  and  8 A- 8 C for manufacturing these structures where the apparatus has 3 chambers with the option of 4/5 chambers for multilayer metals, metal alloys/dielectric deposition with and without a cure treatment in a lower chamber of the apparatus. 
         [0034]    Metal liner layers around and abutting copper via connectors are used in copper interconnect technology to prevent corrosion of the copper wires by sealing the side surfaces of the wires between wiring levels. Metal capping layers are also provided for the same reasons. As wire dimensions decrease however, current density increases and the “weakest” site for resisting electromigration failure is at the metal layer/copper interface. Metal liner layers and capping layers improve electromigration performance but at the cost of increased copper corrosion failures. The inventors have discovered that the increased corrosion failure rates are due to oxygen at the metal cap/copper and metal/alloy liner interface caused by oxygen diffusion through the metal cap or alloy liner. 
         [0035]    The present invention, inter alia, resolves these problems by providing a metal alloy liner on the surface of the copper metal conductor in the via and optionally a metal alloy capping layer on the copper metal conductor for improved electromigration and TDDB performance. A dielectric layer can also be employed as an oxygen barrier on the metal alloy liner capping layers. In the description that follows, the processes relating to the deposition and/or treatment of the caps also applies to the liners of the invention. 
         [0036]    The best results however, are obtained when both the metal and dielectric layers are formed in a non-oxygen atmosphere and between depositing the metal alloy liner layer or capping layer and the copper interconnect structure (with the metal alloy liner or capping layer in place) is not exposed to oxygen (or other copper corroding material). 
         [0037]    A damascene process is one in which wire trenches or via openings are defined by a patterned hardmask layer and etched into an underlying interlevel dielectric (ILD) layer, an electrical conductor of sufficient thickness to fill the trenches is deposited, and a chemical-mechanical-polish (CMP) process is performed to remove excess conductor and the hardmask layer and to make the surface of the conductor co-planar with the surface of the dielectric layer to form damascene wires (or damascene vias). When only a trench and a wire (or a via opening and a via) is formed the process is called single-damascene. The pattern in the hardmask is photolithographically defined. 
         [0038]    A dual dual-damascene process is one in which wire trenches are defined by a patterned hardmask layer and etched partway into an underlying ILD layer followed by formation of vias inside the trenches through the remaining thickness of the ILD layer in cross-sectional view. All via openings are intersected by integral wire trenches above and by a wire trench below, but not all trenches need intersect a via opening. Thereafter the process is the same as for single-damascene wires. 
         [0039]    In  FIG. 1A , an ILD layer  100  is formed on a substrate  105 . In semiconductor processing, substrate  105  is called a wafer and is a flat circular disk having, for example, diameters of 100, 125, 200 or 300 mm and thicknesses of about several hundred to about a thousand microns. Substrate  105  includes a semiconductor (e.g., silicon) layer on/and in which various dielectric and conductive layers have been built up to form devices such as transistors. Substrate  105  may also include other wiring levels having metal contacts, damascene wires and/or dual damascene wires formed in respective ILD layers. A first trench  110  and a second trench  115  are formed in ILD layer  100 . Trench  110  is where a damascene wire will be formed. Trench  115  is where a dual-damascene wire will be formed. Trench  115  includes a wire opening  120  open to a via opening  125 . Substrate  105  is exposed in the bottom of via opening  125 . While first trench  110  is not open to substrate, in some applications, notably first wiring levels that contain only damascene wires, trench  110  will be open to substrate  105  and subsequently fabricated wires physically and electrically contact metal stud contacts and/or portions of devices such as field effect transistors, bipolar transistors, diodes, resistors, capacitors and other semiconductor devices. 
         [0040]    In one example, ILD layer  100  comprises a porous or nonporous silicon dioxide (SiO 2 ), fluorinated SiO 2  (FSG) or a low K (dielectric constant) material, examples of which Include but are not limited to hydrogen silsesquioxane polymer (HSQ), methyl silsesquioxane polymer (MS Q), SiLK.™. (polyphenylene oligomer) manufactured by Dow Chemical, Midland, Tex., Black Diamond.™. (methyl doped silica or SiO x (CH 3 ) y  or SiC x O. y H. y or SiOCH) manufactured by Applied Materials, Santa Clara, Calif., organosilicate glass (SiCOH), and porous SiCOH. A low K dielectric material has a relative permittivity of about 2.4 or less. In one example, ILD layer  100  is from about 50 nm to about 700 nm thick. 
         [0041]    In  FIG. 1B , a first metal alloy liner layer  130  is formed on all exposed surfaces of ILD  100  and substrate  105 . A second metal alloy liner layer  135  is formed on first metal alloy liner layer  130 . In one example, a layer of Co and second liner layer  135  comprises MnW In one example, we provide a first liner layer of MnW and a second liner layer  135  that comprises Co and/or In another example, first liner layer  130  comprises a layer of MnCo and second liner layer  135  comprises W. In yet another example, first liner layer  130  comprises a layer of MnCo and second liner layer  135  comprises W. 
         [0042]    The metal alloy liner layers in another aspect of the invention comprise alloys of Mn, with Co and/or W (i.e., a Co/Mn, Co/Mn/W, W/Mn, W/Mn/Co alloy) in the following amounts: 
         [0043]    Mn, about 0.1 to about 20 parts by weight; 
         [0044]    Co, 0 to about 100 parts by weight; 
         [0045]    W, 0 to about 100 parts by weight. 
         [0000]    We form these alloy metal liners by depositing precursors of Mn, with Co and/or W precursors sequentially, or co-depositing the precursors by concurrent flow of multiple precursors, so as to produce a nano-intercalated metal alloy liner film or series of metal films, i.e., a series of metal layers that alloy with one another or a series of metal alloy layers. 
         [0046]    In  FIG. 1C , a copper seed layer  140  is formed on second metal alloy liner layer  135 . In one example, copper seed layer  140  may be formed, for example, by evaporation or sputter deposition. In  FIG. 1D , a copper layer  145  is formed on copper seed layer  140 . In one example, copper layer  145  is formed by electroplating. 
         [0047]    In  FIG. 1E , a CMP has been performed to form a damascene wire  150  in trench  110  (see  FIG. 1D ) and a dual damascene wire  155  in trench  115  (see  FIG. 1D ). Wire  110  includes a first metal alloy liner  155 A (formed from first metal alloy liner layer  130  of  FIG. 1D ), a second metal alloy liner  160 A (formed from second metal alloy liner layer  135  of  FIG. 1D ) and a copper core conductor  165 A formed from copper seed layer  140  and copper layer  145  of  FIG. 1D ). Wire  115  includes a first metal alloy liner  155 B (formed from first metal alloy liner layer  130  of  FIG. 1D ), a second metal alloy liner  160 B (formed from second metal alloy liner layer  135  of  FIG. 1D ) and a copper core conductor  165 B formed from copper seed layer  140  and copper layer  145  of  FIG. 1D ). After CMP, the top surfaces of wires  150  and  155  are substantially coplanar with a top surface of ILD  100 . 
         [0048]      FIGS. 2A through 2C  are side elevations in cross-section illustrating fabrication of in-situ metal/dielectric caps over the wires of  FIG. 1  according to a first embodiment of the present invention.  FIG. 2A  is the same as  FIG. 1F . However, an optional clean (wet or reactive ion etch (RIE) may be performed prior to loading the wafer (substrate  105 ) into the chamber that will form the metal capping layer illustrated in  FIG. 2B . 
         [0049]    In  FIG. 2B , a selective metal cap  170 A is formed on wire  150  and a selective metal cap  170 B is simultaneously formed on the top surface of wire  155 . The entire top surfaces of copper core  165 A or copper core  165 B are covered by respective metal caps  170 A and  170 B. Metal caps  170 A and  170 B have a thickness Tl. In one example Tl is from about 1 nm to about 50 nm. In one example metal caps  170 A and  170 B consist of one or more metals known in the art. In one example, metal caps  170 A and  170 B Ruthenium (Ru), cobalt (Co), Ti, palladium (Pd), nickel (Ni), gold (Au), iridium (Ir), manganese (Mn), W and combinations thereof, with Ru, Mn, Co and combinations thereof preferred and Ru most preferred. 
         [0050]    Metal caps  170 A and  170 B are formed by selective deposition of the metal on Cu. The selective deposition techniques include chemical vapor deposition (CVD) and atomic layer deposition (ALD). It is a feature of the present invention that metal caps  170 A and  170 B be formed in a non-oxygen (i.e., no free O, O 2 , or O 3 ) atmosphere. Selective processes according to embodiments of the present invention involve self-complementary materials and are self-limiting depositions of a metal from a reactive vapor phase compound of the metal exclusively on exposed Cu. The Mn, or W, or Co composition of  170 A and/or  170 B referred to below comprises a Co/Mn, Co/Mn/W, W/Mn, W/Mn/Co alloy: 
         [0051]    Mn, about 0.1 to about 20 parts by weight; 
         [0052]    Co, 0 to about 100 parts by weight; 
         [0053]    W, 0 to about 100 parts by weight. 
         [0000]    In one example, Mn may be selectively deposited on Cu using Manganese hexacacarbonyl (Mn(CO) 6 ) precursor or the Manganese amidinate in a CVD reaction. Cobalt, (Co) may be selectively deposited on Cu using dicarbonyl (h5-2,4-cycopentadien-1-yl)Co precursor in a CVD reaction. Tungsten, (W) may be selectively deposited on Cu using tungsten hexacacarbonyl (W(CO) 6 ) precursor in a CVD reaction. Both Co Amidinate and Tungsten Amidinate can also be used as precursors. We also use the foregoing Mn, Co, and W precursors to form the liners of this invention. 
         [0054]    In  FIG. 2C , a dielectric cap  175  is formed on metal caps  170 A and  170 B, any exposed regions of wires  150  and  155  (e.g., exposed metal alloy liners) and on ILD  100 . Dielectric cap has a thickness T 3 . In one example, T 3  is from about 5 nm to about 100 nm. It is a feature of the present invention that the formation of dielectric cap  175  is performed in a non-oxygen atmosphere and that the structure of  FIG. 2B  not exposed to oxygen before dielectric cap  175  is formed. Dielectric cap  175  is formed by blanket or non-selective CVD. In one example, dielectric cap  175  is silicon nitride (Si 3 N 4 ) or (SiN), silicon carbide (SIC), Silicon oxynitride (SiNO) or amorphous silicon carbonitride (SiC y N x :H). It is a feature of the present invention that dielectric cap  175  be formed in a non-oxygen (i.e., no free O, O.sub.2, or O.sub.3) atmosphere. The CVD reactants may contain bound oxygen atoms that are released as bound oxygen atoms (e.g., CO, CO 2 ) by the deposition reaction. It is preferred that dielectric cap  175  not be formed from a material containing oxygen. The metal cap  170 A and  170 B to core conductor  165 A and  165 B interfaces do not contain oxygen. 
         [0055]      FIGS. 3A through 3D  are side elevations in cross-section illustrating fabrication of in-situ metal/dielectric caps over the wires of  FIG. 1  according to a second embodiment of the present invention. The second embodiment differs from the first, only in that an additional step is performed between the step illustrated in  FIG. 2B  and the step illustrated in  FIG. 2C .  FIGS. 3A and 3B  therefore are the same as  FIGS. 2A and 2B . An optional clean (wet or reactive ion etch (RIE)) may be performed prior to loading the wafer (substrate  105 ) into the chamber that will form the metal capping layer illustrated in  FIG. 3B . 
         [0056]    In  FIG. 3C , alloy caps  180 A and  180 B are simultaneously formed on respective metal caps  170 A and  170 B. Alloy caps  180 A and  180 B have a thickness T 3 . In one example, T 3  is from about 0.5 nm to about 5 nm. Exemplary materials for alloy caps  180 A and  180 B include, but are not limited to Co, W, and Mn. The Mn, W, Co composition of  180 A and  180 B comprise a Co/Mn, Co/Mn/W, W/Mn, W/Mn/Co alloy: 
         [0057]    Mn, about 0.1 to about 20 parts by weight; 
         [0058]    Co, 0 to about 100 parts by weight; 
         [0059]    W, 0 to about 100 parts by weight. 
         [0060]    Alloy caps  180 A and  180 B are formed by selective deposition on metal caps  170 A and  170 B respectively. The selective deposition technique include chemical vapor CVD and ALD. It is a feature of the present invention that alloy caps  180 A and  180 B be formed in a non-oxygen (i.e., no free O, O 2 , or O 3 ) atmosphere. It is a feature of the present invention that the structure of  FIG. 3B  not be exposed to oxygen before alloy caps  180 A and  180 B are formed. 
         [0061]      FIG. 3D  is similar to  FIG. 2C  except for the presence of alloy caps  180 A and  180 B. It is a feature of the present invention that dielectric cap  175  be formed in a non-oxygen (i.e., no free O, O 2 , or O 3 ) atmosphere. Dielectric cap  175  is formed on alloy caps  180 A and  180 B, any exposed regions of metal caps  170 A and  170 B, any exposed regions of metal alloy liners  155 A,  155 B,  160 A and  160 B and ILD  100 . It is a feature of the present invention that the structure of  FIG. 3C  not be exposed to oxygen before dielectric cap  175  is formed. The metal cap  170 A and  170 B to core conductor  165 A and  165 B interfaces do not contain oxygen. 
         [0062]      FIGS. 4A through 4D  are side elevations in cross-section illustrating variations to the first and second embodiments of the present invention. Returning to  FIG. 2B  or  3 B, the edges of metal caps  170 A and  170 B are aligned to respective metal alloy liner  155 A/ 160 A and metal alloy liner  155 B/ 160 B interfaces. This is a first variation. In  FIG. 4A , a metal cap  170  is aligned to the metal alloy liner  160 /core conductor interface. This is a second variation. In  FIG. 4B , metal cap  170  overlaps metal alloy liner  160 , but not metal alloy liner  155 . This is a third variation. In  FIG. 4C , metal cap  170  overlaps metal alloy liners  160  and  155  but not ILD  100 . This is a fourth variation. In  FIG. 4D , metal cap  170  is aligned to the metal alloy liner  155 /ILD  100  interface. In a fifth variation, metal cap layer  170  overlaps ILD  100  in a region immediately adjacent to metal alloy liner  155 . 
         [0063]      FIGS. 5A through 5D  are side elevations in cross-section illustrating fabrication of in-situ metal/dielectric caps over the wires of  FIG. 1  according to a third embodiment of the present invention.  FIG. 5A  is the same as  FIG. 1E . In  FIG. 5B , a copper recess etch is performed on core conductors  185 A and  185 B of  FIG. 5A  to form recessed core conductors  205 A and  205 B of respective wires  200  and  210 . Respective top surfaces  195 A and  195 B of core conductors  205 A and  205 B are recessed below top surface  190  of ILD  100  a distance Dl. In one example, D 1  is from about 10 to about 50 nm, preferably from about 20 and 35 nm. 
         [0064]    In  FIG. 5C , metals caps  170 A and  170 B are formed on respective core conductors  205 A and  205 B. In the example of  FIG. 5C , respective top surfaces  215 A and  215 B of metal caps  170 A and  170 B extend above top surface  190  of ILD  100 . Processes for forming and materials for metal caps  170 A and  170 B have been discussed supra. No portions of core conductors  205 A or  205 B are exposed. 
         [0065]    In  FIG. 5D , dielectric cap  175  is formed on metal caps  170 A and  170 B, any exposed regions of wires  200  and  210  (e.g., exposed metal alloy liners) and on ILD  100 . It is a feature of the present invention that dielectric cap  175  be formed in a non-oxygen (i.e., no free O, O 2 , or O 3 ) atmosphere. It is a feature of the present invention that the structure of  FIG. 5C  is not exposed to oxygen before dielectric cap  175  is formed. The metal cap  170 A and  170 B to core conductor  165 A and  165 B interfaces do not contain oxygen. It is preferred that dielectric cap  175  not be formed from a material containing oxygen. 
         [0066]      FIGS. 5A through 5C  and  5 E- 5 F are side elevations in cross-section illustrating fabrication of in-situ metal/dielectric caps over the wires of  FIG. 1  according to a fourth embodiment of the present invention.  FIGS. 5A through 5C  have been discussed supra. In  FIG. 5E  alloy caps  180 A and  180 B are formed on respective metal cap  170 A and  170 B. Processes for forming and materials for alloy caps  180 A and  180 B have been discussed supra. It is a feature of the present invention that alloy caps  180 A and  180 B be formed in a non-oxygen (i.e., no free O, O 2 , or O 3 ) atmosphere. It is a feature of the present invention that the structure of  FIG. 5C  not be exposed to oxygen before alloy caps  180 A and  180 B are formed. In  FIG. 5F , dielectric cap  175  is formed on alloy caps  180 A and  180 B, any exposed regions of alloy caps  170 A and  170 B, any exposed regions of wires  150  and  155  (e.g., exposed metal alloy liners) and on ILD  100 . It is a feature of the present invention that dielectric cap  175  be formed in a non-oxygen (i.e., no free O, O 2 , or O 3 ) atmosphere. It is a feature of the present invention that the structure of  FIG. 5E  not be exposed to oxygen before dielectric cap  175  is formed. The metal cap  170 A and  170 B to core conductor  165 A and  165 B interfaces do not contain oxygen. 
         [0067]      FIGS. 6A and 6B  are side elevations in cross-section illustrating variations to the third and fourth embodiments of the present invention. Returning to  FIG. 5C , respective top surfaces  215 A and  215 B of metal caps  170 A and  170 B extend above top surface  190  of ILD  100 . This is a first variation. In  FIG. 6A , a top surface  215  off a metal cap  170  is coplanar with top surface  190  of ILD  100 . This is a second variation. In  FIG. 6B , top surface  215  of metal cap  170  extends above top surface  190  of ILD  100 . This is a third variation. 
         [0068]      FIGS. 7A through 7D  illustrate a first set of tools for forming in-situ interconnects according to the first and third embodiments of the present invention. In  FIGS. 7A through 7D  it should be understood that a CVD chamber performs a CVD deposition process and an ALD chamber performs an ALD deposition process. An ALD/CVD chamber is capable of selectively performing either an ALD deposition process or a CVD deposition process. Further, CVD deposition of dielectric layers (dielectric caps) is a blanket or non-selective deposition. 
         [0069]    In  FIG. 7A , a deposition tool  300  includes a load/unload chamber  305 A, a CVD chamber  310  and a CVD chamber  315 . Load/unload chamber  305 A is capable of being purged with a non-oxygen containing and inert gas, for example nitrogen (N 2 ). Load/unload chamber  305 A includes a mechanism for loading and unloading wafers, for transferring wafers between chambers  305 A,  310  and  315  of tool  300 . Chambers  310  and  315  are connected to load/unload chamber  305 A by ports, which can be closed during deposition. CVD chamber  310  is configured to deposit metal liners and CVD chamber  315  is configured to deposit dielectric liners or caps. In use, the following steps are performed: (1) a wafer(s) is loaded into load/unload chamber  305 A and load/unload chamber  305 A purged with inert gas, (2) the wafer(s) is transferred into CVD chamber  310  where metal liners are formed and then CVD chamber  310  is purged with an inert gas, (3) the wafer(s) is transferred from CVD chamber  310 , through load/unload chamber  305 A (which is essentially free of oxygen) to CVD chamber  315 , without exposure to air or oxygen, where a dielectric liner is deposited and then CVD chamber  315  is purged with inert gas, (4) the wafer(s) is transferred from CVD chamber  315  to load/unload chamber  305 A (which is essentially free of oxygen), and (5) the wafer(s) is unloaded from load/unload chamber  305 A. All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. 
         [0070]    In  FIG. 7B , a deposition tool  320  includes load/unload chamber  305 A, an ALD chamber  325  and CVD chamber  315 . ALD chamber  325  is configured to deposit metal liners and CVD chamber  315  is configured to deposit dielectric liners or caps. Load/unload chamber  305 A Includes a mechanism for loading and unloading wafers, for transferring wafers between chambers  305 A,  315  and  325  of tool  320 . Chambers  315  and  325  are connected to load/unload chamber  305  A by ports, which can be closed during deposition. In use, the following steps are performed: (1) a wafer(s) is loaded into load/unload chamber  305 A and load/unload chamber  305 A purged with inert gas, (2) the wafer(s) is transferred into ALD chamber  325  where metal liners are formed and then ALD chamber  325  is purged with an inert gas, (3) the wafer(s) is transferred from ALD chamber  325 , through the load/unload chamber  305 A (which is essentially free of oxygen) to CVD chamber  315 , without exposure to air or oxygen, where a dielectric liner is deposited and then CVD chamber  315  is purged with an inert gas, (4) the wafer(s) is transferred from CVD chamber  315  to load/unload chamber  305 A (which is essentially free of oxygen), and (5) the wafer(s) is unloaded from load/unload chamber  305 A. All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. In  FIG. 7C , a deposition tool  330  includes load/unload chamber  305 B, and a CVD chamber  335  configured for CVD deposition of metals and dielectrics. Load/unload chamber  305 B includes a mechanism for loading and unloading wafers and for transferring wafers between chambers  305 B and  335  of tool  330 . Chamber  335  is connected to load/unload chamber  305 B by a port, which can be closed during deposition. In use, the following steps are performed: (1) a wafer(s) is loaded into load/unload chamber  305 B and load/unload chamber  305  purged with inert gas, (2) the wafer(s) is transferred into CVD chamber  335  where metal liners are formed by CVD, then a dielectric liner is formed by CVD, and then CVD chamber  335  is purged with inert gas, (3) the wafer(s) is transferred from CVD chamber  335  to load/unload chamber  305 B (which is essentially free of oxygen), and (4) the wafer(s) is unloaded from load/unload chamber  305 B. All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. 
         [0071]    In  FIG. 7D , a deposition tool  340  includes load/unload chamber  305 , and an ALD/CVD chamber  345  configured for ALD deposition of metals and CVD deposition of dielectrics. Load/unload chamber  305 B includes a mechanism for loading and unloading wafers and for transferring wafers between chambers  305 A and  345  of tool  340 . Chamber  345  is connected to load/unload chamber  305 B by a port, which can be dosed during deposition. In use, the following steps are performed: (1) a wafer(s) is loaded into load/unload chamber  305 B and load/unload chamber  305 B is purged with inert gas, (2) the wafer(s) is transferred into ALD/CVD chamber  345  where metal liners are formed by ADD, then a dielectric liner is formed by CVD and then ALD/CVD chamber  345  is purged with an inert gas, (3) the wafer(s) is transferred from ALD/CVD chamber  345  to load/unload chamber  305 B (which is essentially free of oxygen), and (4) the wafer(s) is unloaded from load/unload chamber  305 B. All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. 
         [0072]      FIGS. 8A through 8C  illustrate a second set of tools for forming in-situ interconnects according to the second and fourth embodiments of the present invention. In  FIGS. 8A through 8C  it should be understood that a CVD chamber performs a CVD deposition process and an ALD chamber performs an ALD deposition process. An ALD/CVD chamber is capable of selectively performing either an ALD deposition process or a CVD deposition process. Further, CVD deposition of dielectric layers (dielectric liners or caps) is a blanket or non-selective deposition. 
         [0073]    In  FIG. 8A , a deposition tool  400  includes a load/unload chamber  405 A, a first chamber  410 , a second chamber  415  and a third chamber  420 . First chamber  410  is configured to either form metal liners by (a) CVD or (b) metal liners by ALD but not both. Second chamber is configured to form alloy liners by (a) CVD or (b) ALD but not both. Third chamber  420  is configured to form a dielectric liner by CVD. Load/unload chamber  405 B includes a mechanism for loading and unloading wafers and for transferring wafers between chambers  405 A,  410 ,  415  and  420  of tool  400 . Chambers  410 ,  415  and  420  are connected to load/unload chamber  405 A by a port, which can be closed during deposition. Load/unload chamber  405 A is capable of being purged with a non-oxygen containing and inert gas, for example N 2 . In use, the following steps are performed: (1) a wafer(s) is loaded into load/unload chamber  405 A and the load/unload chamber purged with the inert gas, (2) the wafer(s) is transferred into first chamber  410  where metal liners are formed by either ALD or CVD and then first chamber  410  is purged with inert gas, (3) the wafer(s) is transferred from first chamber  410 , through the load/unload chamber  405  (which is essentially free of oxygen) to second chamber  415 , without exposure to air or oxygen, where alloy liners are formed by either ALD or CVD and then second chamber  415  is purged with inert gas, (4) the wafer(s) is transferred from second chamber  415 , through load/unload chamber  405 A (which is essentially free of oxygen) to third chamber  420 , without exposure to air or oxygen, where a dielectric liner is formed by CVD and then third chamber  420  is purged with inert gas, (5) the wafer(s) is transferred from third chamber  420  to load/unload chamber  405 A (which is essentially free of oxygen), and (6) the wafer(s) is unloaded from load/unload chamber  405 A. All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. 
         [0074]    In  FIG. 8B , a deposition tool  425  includes load/unload chamber  405 B, a first chamber  430  and second chamber  435 . Load/unload chamber  405 B includes a mechanism for loading and unloading wafers, for transferring wafers between chambers  405 B,  430  and  435  of tool  425 . Chambers  430  and  435  are connected to load/unload chamber  405 B by ports, which can be closed during deposition. First chamber  430  is configured to form (a) metal liners by CVD and alloy liners by CVD, or (b) metal liners by CVD and alloy liners by ALD, or (c) metal liners by ALD and alloy liners by CVD or (d) metal liners by ALD and alloy liners by ALD. Second chamber  435  is configured to form a dielectric liner by CVD. Load/unload chamber  405 B is capable of being purged with a non-oxygen containing and inert gas, for example N 2 . In use, the following steps are performed: (1) a wafer(s) is loaded Into load/unload chamber  405 B and the load/unload chamber purged with the inert gas, (2) the wafer(s) is transferred into first chamber  430  where metal liners are formed by either ALD or CVD and then alloy liners are formed by either ALD or CVD and then first chamber  435  is purged with inert gas, (3) the wafer(s) is transferred from first chamber  430 , through the load/unload chamber  405  (which is essentially free of oxygen) to second chamber  435 , without exposure to air or oxygen, where a dielectric liner is formed by CVD and then second chamber  435  is purged with inert gas, (4) the wafer(s) is transferred from second chamber  435  to load/unload chamber  405 B (which is essentially free of oxygen), and (5) the wafer(s) is unloaded from load/unload chamber  405 B. All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. 
         [0075]    In  FIG. 8C , a deposition tool  440  includes load/unload chamber  405 C, and deposition chamber  455  configured to form (a) metal liners or caps, alloy liners and a dielectric liner by CVD, or (b) metal caps by CVD, alloy caps by ALD and a dielectric liner by CVD, or (c) metal alloy liners by ALD and a dielectric liner by CVD, or (d) metal liners and alloy liners by MD and a dielectric liner by CVD. Load/unload chamber  405 C includes a mechanism for loading and unloading wafers and for transferring wafers between chambers  405 C and  445  of tool  440 . Chamber  445  is connected to load/unload chamber  405 C by a port, which can be closed during deposition. In use, the following steps are performed: (1) a wafer(s) is loaded into load/unload chamber  405 C and the load/unload chamber purged with the inert gas, (2) the wafer(s) is transferred into process chamber  440  where metal caps are formed by either ALD or CVD, then alloy caps are formed by either ALD or CVD, then a dielectric liner is formed by CVD and then process chamber  440  is purged with inert gas, (3) the wafer(s) is transferred from process chamber  440  to load/unload chamber  405 C (which is essentially free of oxygen), and (4) the wafer(s) is unloaded from load/unload chamber  405 . All chambers are sealed except when the wafer(s) is being transferred, loaded or unloaded. 
         [0076]    The immediately foregoing aspects of the disclosure therefore comprise a deposition tool that includes: a load/unload chamber; a mechanism for transferring a substrate between the load/unload chamber and a deposition chamber, the deposition chamber connected to the load/unload chamber by a port; and wherein the deposition chamber is (i) configured to selectively form a metal layer or layers on copper by chemical vapor deposition or by atomic layer deposition and (ii) is configured to form a dielectric layer by chemical vapor deposition. 
         [0077]    The deposition tool of this aspect of the disclosure is further configured to selectively deposit a metal alloy layer on the metal layer by chemical vapor deposition or by atomic layer deposition and may include: a load/unload chamber, first and second deposition chambers connected to the load/unload chamber by respective ports; a mechanism for transferring a substrate between the first deposition chamber, the second deposition chamber and the load/unload chamber; wherein the first deposition chamber configured to selectively form a metal layer on copper by chemical vapor deposition or by atomic layer deposition; and wherein the second deposition chamber is configured to form a dielectric layer by chemical vapor deposition; the first and second deposition chambers may be re configured for chemical vapor deposition or (ii) the first deposition chamber is configured for atomic layer deposition and the second deposition chamber is configured for chemical vapor deposition; the first chambers may also be configured to form a metal alloy layer on the metal layer by either selective chemical vapor deposition or selective atomic layer deposition; the deposition tool may include a third deposition chamber configured to selectively form a metal alloy on a metal; and wherein (i) the first, second and third deposition chambers are configured for chemical vapor deposition or (ii) the first and third deposition chamber are configured for chemical vapor deposition and the second chamber is configured for atomic layer deposition, or (iii) the second and third deposition chambers are configured chemical vapor deposition and the first chamber is configured for atomic layer deposition, or (iv) the first and second deposition chambers are configured for atomic layer deposition and the third deposition chamber is configured for chemical vapor deposition. 
         [0078]    Throughout this specification, and abstract of the disclosure, the inventors have set out equivalents, of various materials as well as combinations of elements, materials, compounds, compositions, conditions, processes, structures and the like, and even though set out individually, also include combinations of these equivalents such as the two component, three component, or four component combinations, or more as well as combinations of such equivalent elements, materials, compositions conditions, processes, structures and the like in any ratios or in any manner. 
         [0079]    Additionally, the various numerical ranges describing the invention as set forth throughout the specification also includes any combination of the lower ends of the ranges with the higher ends of the ranges, and any single numerical value, or any single numerical value that will reduce the scope of the lower limits of the range or the scope of the higher limits of the range, and also includes ranges falling within any of these ranges. 
         [0080]    The terms “about,” “substantial,” or “substantially” as applied to any claim or any parameters herein, such as a numerical value, including values used to describe numerical ranges, means slight variations in the parameter or the meaning ordinarily ascribed to these terms by a person with ordinary skill in the art. In another embodiment, the terms “about,” “substantial,” or “substantially,” when employed to define numerical parameter include, e.g., a variation up to five per-cent, ten per-cent, or 15 per-cent, or somewhat higher. Applicants intend that terms used in the as-filed or amended written description and claims of this application that are in the plural or singular shall also be construed to include both the singular and plural respectively when construing the scope of the present invention. 
         [0081]    All scientific journal articles and other articles, including Internet sites, as well as issued and pending patents that this written description or applicants&#39; Invention Disclosure Statements mention, including the references cited in such scientific journal articles and other articles, including Internet sites, and such patents, are incorporated herein by reference in their entirety and for the purpose cited in this written description and for all other disclosures contained in such scientific journal articles and other articles, including internet sites as well as patents and the references cited therein, as all or any one may bear on or apply in whole or in part, not only to the foregoing written description, but also the following claims, and abstract of the disclosure. 
         [0082]    Although we describe the invention by reference to some embodiments, other embodiments defined by the doctrine of equivalents are intended to be included as falling within the broad scope and spirit of the foregoing written description, and the following claims, abstract of the disclosure, and drawings.